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Case No:98/1008/CMS3
IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM CHANCERY DIVISION
MR JUSTICE PUMFREY
Royal Courts of Justice
Strand, London, WC2A 2LL
Monday 20th March 2000
B e f o r e :
LORD JUSTICE HENRY
and
LORD JUSTICE ALDOUS
(1) Boston Scientific Limited
(2) Boston Scientific International BV
(Respondents)
AND
(1) Julio C. Palmaz
(2) Expandable Grafts Partnership
(Appellants)
- - - - - - - - - - - - - - - - - - - - -
(Transcript of the Handed Down Judgment of
Smith Bernal Reporting Limited, 180 Fleet Street
London EC4A 2HD
Tel No: 0171 421 4040, Fax No: 0171 831 8838
Official Shorthand Writers to the Court)
- - - - - - - - - - - - - - - - - - - - -
Michael Silverleaf QC and Emma Himsworth (instructed by Linklaters for
the Appellants)
David Kitchin QC and Andrew Waugh QC (instructed by Eversheds for the
Respondents)
- - - - - - - - - - - - - - - - - - - - -
Judgment
As Approved by the Court
Crown Copyright ©
LORD JUSTICE ALDOUS:
1. In his judgment of 26th June 1998, Pumfrey J held European patents (UK) Nos.
221 570 (Palmaz 1) and 335 341 (Palmaz 2) invalid and not infringed and ordered
their revocation subject to a stay pending appeal. Against that decision the
patentees Dr Julio Palmaz and Expandable Grafts Partnership appeal.
2. The proceedings started life as actions for declarations of non-infringement
and petitions to revoke the patents brought by Boston Scientific Ltd and Boston
Scientific International BV. There is no need to differentiate between them
and I will refer to them as Boston.
3. Both the patents are for inventions entitled "Expandable Intra-luminal
Graft, and Apparatus for implanting an expandable intra-luminal graft". They
are in the main concerned with coronary stents. A stent is a device for
supporting the walls of a body passageway to keep a lumen or tube open. It can
be regarded in simple terms as scaffolding. Stents have a variety of uses in
the treatment of disease of various ducts and vessels in the human body. One
of the most important is the treatment of coronary artery disease.
4. As the judge explained:
" Coronary heart disease is caused by a narrowing or blockage of the coronary
arteries which supply the heart muscle with blood. Arterial walls have three
layers: a very thin inner layer called the intima, a middle layer called the
media which consists of muscle, both maintaining the structural integrity of
the artery and allowing it to contract and dilate, and an outer layer called
the adventitia, which is a loose layer of connective tissue. The usual cause of
arterial narrowing is atherosclerosis, in which there is a gradual build up of
fatty material in the inner layer of the artery wall, followed by deposition of
fibrous tissue to produce a plaque which protrudes into the channel (lumen) of
the artery. This narrowing is called a stenosis. As the lumen becomes
progressively narrowed, the heart muscle fed by the artery concerned becomes
deprived of blood when demands are made of it, for example during exercise. The
patient may then complain of angina, which is typically a crushing or
constricting sensation in the chest and which may spread elsewhere, for example
in the left arm or neck. If the protective fibrous cap on the surface over the
fat laden core (the so-called atheroma) breaks (there is much ongoing research
into the causes of this break or "fissure") the platelets in the bloodstream
adhere to the roughened exposed surface and a blood clot forms. The patient's
angina may worsen or suddenly appear at this time (unstable angina). If the
lumen of the artery suddenly closes off, blood flow ceases and the heart muscle
dies, resulting in a heart attack (myocardial infarction.).
At the priority date of Palmaz I, there were essentially three methods of
treating coronary heart disease: drugs, coronary bypass surgery and
angioplasty. Drugs may be used to relieve the symptoms of angina by relaxing
the muscle of the artery wall, which improves the supply of blood to the heart
muscle. They may also be used to make the heart beat less forcefully, so
reducing its workload. Clot-dissolving drugs may be used, as may anti-platelet
drugs, which reduce the tendency of the platelets (red blood cells) to adhere
to the plaques.
If drugs alone are insufficient, and there is narrowing and blockage in several
arteries, the patient may undergo coronary artery bypass surgery, in which
vessels from elsewhere in the patient's body are used to bypass the problem by
connecting them to the artery beyond the blockage. I understand that this
surgery can relieve angina, and may be successful for many years if the grafts
remain open. It will be apparent that surgical intervention requires general
anaesthetic, is expensive and time-consuming and involves major trauma for the
patient but the evidence was that mortality is low (2 per cent).
Finally, angioplasty. This technique was initially developed in the early 1960s
but its application to the coronary arteries became possible after the
development of a balloon which, when inflated, was strong enough to dilate an
arterial stenosis in a coronary artery. One Andreas Grüntzig in Zurich
developed a catheter with a relatively non-elastic sausage shaped balloon near
its tip. The catheter had two channels: one for introducing a guide wire along
which the balloon catheter could be passed and the other channel to inflate the
balloon with fluid at a high pressure (between 6 and 12 bar, that is about 6-12
atmospheres. The pressure in a car tyre is about 2-2.5 atmospheres). The
procedure was carried out first in the peripheral arteries, and then extended
to the coronary arteries. The first percutaneous angioplasty was performed in
September 1977. It is referred to as percutaneous because the catheter is
passed through the skin into an artery.
Professor Cumberland describes the angioplasty procedure as follows. An outer
catheter, called a guide catheter, is passed through the skin into the arterial
system, usually into the femoral artery in the groin or into an artery in the
arm. Using x-ray screening for guidance, the operator steers the guide catheter
into a coronary artery. This involves manipulating the catheter into the aorta
and from there into one of the coronary arteries. Radio opaque fluid is
injected via the catheter, mixes with the blood and passes down the artery,
revealing the lumen of the vessels and their branches for a few seconds each
time. For angioplasty, a fine guidewire (0.014"sec; diameter) is passed through
the catheter into the coronary branches. The wire is steered under x-ray
control through the diseased portion of the arteries. The balloon catheter,
with a balloon near its tip is then passed over this wire and the operator
positions the balloon at the site of the narrowing in the artery. The balloon
is then inflated ..... Typical balloon dimensions are 2.5-4mm inflated diameter
and 20mm length.
....
The technique was recognised to have certain disadvantages and problems ...
But balloon angioplasty has become a very successful technique, and Professor
Cumberland estimates that one million such procedures are performed annually
throughout the world. At the priority date of Palmaz I (which is accepted to be
November 7, 1985) balloon angioplasty was a well-known procedure, and was
rapidly developing.
Stents are adjuncts to the balloon angioplasty procedure. Essentially they
consist of devices which are inserted into the diseased artery at the point at
which the balloon has expanded to open the lumen. They act as scaffolding to
hold the artery open and prevent "restenosis". It had been recognised that such
devices would be useful since the early days of angioplasty, and stents in the
form of coiled wires have been proposed as early as 1969 by Dotter who
describes the insertion of tubular coil spring grafts into canine popliteal
arteries. He was not using balloons to expand his stenoses. Later, Dotter made
stents of nitinol, a so-called "memory metal", which had the ability to take up
a new shape on heating."
Palmaz 1
5. Palmaz 1 was applied for in the European Patent Office (EPO) on 7th November
1986 claiming priority from an application made in the USA on 7th November
1985. It was granted on 30th January 1991 and was then opposed by Boston and
another company. By a decision dated 16th June 1993 the Opposition Division of
the EPO held that Palmaz 1, with the claims in the form that they were granted,
was invalid and ordered revocation of the patent. Dr Palmaz appealed against
the order for revocation and put forward amendments to the claims and to the
body of the specification. On 2nd April 1996 the Technical Board of Appeal
ordered the allowance of the patent with the claims amended. However the Board
of Appeal were unhappy with the proposed amendments to the specification and
remitted them to the Opposition Division for further consideration. On 6th May
1998 the Opposition Division allowed the amendments to the specification as
then sought by Dr Palmaz, but that decision was appealed by Boston. Their
appeal was heard by the Technical Board of Appeal and was rejected on 20th
October 1999. The result of the decision of the EPO was to amend the patent.
6. At the time when the judge gave his judgment, the patent had not been
amended. The form of the claims of the patent, as allowed by the Technical
Board of Appeal, was known but the final form of the specification was not.
The judge concluded that the text of Palmaz 1, from which the patentees derived
their rights, was the unamended form including the unamended claims. At that
time he was correct. He went on to consider whether to allow amendment of the
claims and the specification and concluded that he should not. As it was
accepted that the patent was invalid unless the claims were amended, it
followed that Palmaz 1 was invalid and needed to be revoked. However he went
on to consider Palmaz 1 with the amendments to the claims that had been held
allowable in the EPO and concluded that, even with such amendments, the patent
was invalid and not infringed.
7. A European patent takes effect in the United Kingdom, pursuant to section
77(1) of the Patents Act 1977, from the publication of the mention of its grant
in the European Patent Bulletin. Thereafter it is treated for the purposes of
the Patents Act as though it were a patent granted under that Act. There are
two qualifications to the foregoing. Section 77(2) provides that the
provisions of section 77(1) do not affect the operation of any provisions of
the EPC relating to the amendment or revocation of a European Patent (UK) in
proceedings before the EPO and by section 77(4) an amendment made in accordance
with the EPC has effect as if the amendment had been made under the Act. The
effect of those provisions of section 77 is to cause any decision to amend a
European Patent by the EPO under the EPC to have direct effect under UK law.
It follows that amendment of Palmaz 1 by the decision of the EPO in October
1999 resulted in amendment of the UK patent.
8. Boston submitted that the patentees were under a duty to bring before the
court all the issues that needed to be resolved. In the present case they had
chosen to litigate in this country while the opposition was proceeding in the
EPO and had not sought a stay to enable the opposition to be concluded first.
The patentees therefore had to apply to amend in these proceedings and in so
doing had to satisfy the court that the amendments were allowable. The judge
held that they were not and ordered revocation of the patent. It was his
decision which was being reviewed by this Court. It followed that the Court
had to decide amendment, validity and infringement as at the date when the
judge made his order. If the patent was to be revived in the United Kingdom
that could only be done by first reversing the judge's conclusion on amendment.
9. I reject that submission. It is the amended form that has to be considered
in this appeal. The order for revocation was stayed pending appeal. Thus
Palmaz 1 had not been revoked at the time when the EPO decision to allow the
amendments became final. As section 77(4) of the Act makes clear the
amendments allowed by the EPO have to be treated as if made under the 1977 Act.
Such amendments are deemed to always have had effect from the grant of the
patent (see sections 27(3) and 75(3)). Thus the only form that can be
considered is the amended form. The appeal is by way of rehearing and this
Court has power to give any judgment and to make any order which could have
been made or ought to have been made. It follows, taking into account the
retrospective effect of the EPO decision, this Court can only consider the
issues that arise on the appeal in relation to the amended patent which is in
the only form that exists at the date of the hearing before this Court. To do
otherwise would be contrary to common sense.
Palmaz 1 - the specification
10. The specification opens with the consistory clause and then goes on to
acknowledge the prior art. First US patent no. 4553545 which is said to
disclose helically shaped spiral springs used as grafts or stents. Those
grafts, the specification explains, can be generally classified as
self-expanding wires, which, after having been delivered to a stenotic site and
released, are subject to a spring or spring-like force to cause the graft to
enlarge and open outwardly within the body passageways. The specification
points out that such structures that have been used as grafts have included
coiled stainless steel springs, helically wound coil springs manufactured from
an expandable heat-sensitive material and expanding stainless steel stents
formed of stainless steel wire in a zig-zag pattern. The specification then
states:
"In general, the foregoing structures have one major disadvantage in common.
Insofar as these structures must be delivered to the desired location within a
given body passageway in a collapsed state, in order to pass through the body
passageway, there is no effective control over the final, expanded
configuration of each structure. For example, the expansion of a particular
coiled spring-type graft is predetermined by the spring constant and modulus of
elasticity of the particular material utilized to manufacture the coiled spring
structure. These same factors predetermine the amount of expansion of collapsed
stents formed of stainless steel wire in a zig-zag pattern. In the case of
intraluminal grafts, or prostheses, formed of a heat sensitive material which
expands upon heating, the amount of expansion is likewise predetermined by the
heat expansion characteristics of the particular alloy utilized in the
manufacture of the intraluminal graft.
Thus, once the foregoing types of intraluminal grafts are expanded at the
desired location within a body passageway, such as within an artery or vein,
the expanded size of the graft cannot be changed. If the diameter of the
desired body passageway has been miscalculated, an undersized graft might not
expand enough to contact the interior surface of the body passageway, so as to
be secured thereto. It may then migrate away from the desired location within
the body passageway. Likewise, an oversized graft might expand to such an
extent that the spring force, or expansion force, exerted by the graft upon the
body passageway could cause rupturing of the body passageway."
11. The specification then comes to describe the alternative of percutaneous
balloon dilation and to point out the difficulties that had been encountered.
There follows this passage which was introduced by amendment:
"From the article "Expandable Intraluminal Grafts: A Preliminary Study" Palmaz
et al., Radiology, Vol 156 No. 1 July 1985, pp 73-77, a graft comprising all
features of the precharacterising portion of claim 1 is known which is
deliverable mounted on a catheter and is balloon-expandable. It is formed by a
plurarity of intersecting wires which are soldered at each wire intersection.
This graft is schematically shown in Figures 1A and 1B and will be described in
more detail below.
From US-A-3 657 744 another tubular implant structure is known which comprises
the features of the precharacterising portion of claim 1.
....
It is the object of the present invention to provide an expandable graft
having a wide expansion capability, which can be easily inserted and delivered
in a place and, at the same time, which can be expanded to a variable and
controlled size to prevent migration of the graft away from the desired
location."
That object is said to be achieved by features H and I of claim 1, set out
below, which were introduced by amendment.
12. There follows a description of four figures which are attached to this
judgment as Annex I. Figures 1A and B show what, by amendment, is now
acknowledged to be prior art. Figure 1A shows a tubular shaped member 71 which
is said to be made of any suitable material compatible with the human body. It
has elongate members 75 and 76 made of small diameter stainless steel wires
having cylindrical cross-section. Those members are physically secured to one
another where they intersect by, for example, soldering. As illustrated, the
tubular shaped member 71 is made of continuous stainless steel wire woven in a
criss-cross tubular pattern to form what can generally be described as a wire
mesh tube. Figure 1B illustrates the construction of figure 1A after
expansion.
13. Figures 2A and 2B show an embodiment of the invention. Figure 2A is said
to differ from figure 1A in that the plurality of elongate members 75 and 76
have a thin rectangular cross-sectional configuration and are formed integral
with one another. As explained, preferably the tubular shaped member 71 is
initially a thin-walled stainless steel tube and the openings between the
intersecting bars are formed by a conventional etching process, such as
electromechanical or laser etching. The resultant structure is a tubular
shaped member having a plurality of intersecting elongate members. Figure 2B
shows the construction of figure 2A after expansion.
14. Claim 1 broken up into features A-I for convenience is in this form:
"An expandable intraluminal vascular graft or prosthesis (70) for a body
passageway, comprising:
A. a tubular shaped member (71) having first (72) and second (73) ends and a
wall surface (74) disposed between the first and second ends,
B. the wall surface (74) being formed by a plurality of first and second
intersecting members (78, 79), at least some of the first elongate members (78)
intersecting with some of the second elongate members (79) intermediate the
first and the second ends of the tubular shaped member (71),
C. the tubular shaped member (71) having a first diameter (d) which permits
intraluminal delivery of the tubular shaped member into a body passageway
having a lumen,
D. and the tubular shaped member (71) having a second expanded diameter
(d1) which is determined by the application from the interior of the
tubular shaped member (71) of a radially, outwardly extending force,
E. which second diameter (d1) is variable and controlled by the
amount of force applied to the tubular shaped member (71),
F. at least some of the elongate members (78, 79) being deformed by the
radially, outwardly extending force, to retain the tubular shaped member (71)
with the second expanded diameter (d1),
G. whereby the tubular shaped member (71) may be expanded to expand the lumen
of the body passageway and remain therein,
H. characterised in that the first and second intersecting elongate members
(78, 79) are a plurality of thin bars, each having a uniform thin rectangular
cross-sectional configuration,
I. wherein each pair of adjacent first bars (78) is interconnected by at least
two of said second bars (79), each second bar (79) being formed integral with
the respective pair of first bars (78) and extending only between said pair of
first bars (78) and each second bar (79) extending on the circumference of a
circle whose plane is perpendicular to the longitudinal axis of said tubular
shaped member (71)."
Palmaz 1 - Infringement
15. The alleged infringement is called the NIR stent. It is shown in Annex II
to this judgment.
16. The acts alleged to infringe are admitted, but Boston contend that the
NIR stent does not fall within the ambit of claim 1 of this patent. It is
manufactured in an unexpanded form (Figure 1A) and may be crimped over the
balloon and then expanded (Figure 2). The judge described it correctly in this
way:
"Essentially, the structure of the stent is uniform, being built up of
identical unit cells. These cells may be viewed as composed of one horizontal,
or C-shaped hoop and one vertical hoop, or U-shaped hoop. On expansion, both
sets of hoops expand. The effect of the expansion of the C-shaped
(longitudinal) hoop is that the radius of the stent increases. The effect of
the expansion of the U-shaped (circumferential) hoops is that the longitudinal
contraction of the stent which would otherwise occur is substantially
decreased."
The judge concluded that the NIR stent did not infringe claim 1. He said:
"Boston argue that this stent lacks features B, H and I of the claim. I agree
that it is not possible sensibly to identify two sets of intersecting elongate
members in the alleged infringement, one of which sets is generally
circumferential. It follows that none of the interconnections specified by
feature I is present, and feature B is not present. There is no scope in this
case for an argument of infringement based upon the suggestion that the NIR
stent embodies some variant of one or more features of the claim, which can be
said to be encompassed by the claim on the approach to construction described
in Catnic v. Hill & Smith [1982] R.P.C. 183 at 242, line 44 et seq.
and explained in Improver v Remington [1990] F.S.R. 181 at 188. The
problem is to identify the variant. This is not just a departure from some
descriptive word or phrase, or a matter of degree: it is the omission of whole
features of the claim. There is no basis for such an approach to construction,
above all where the specification does not describe the reason for the presence
of the features in the claim, which have been added by amendment. The
construction of the claim must give reasonable protection for the patentee and
a reasonable degree of certainty for third parties - see the Protocol on the
Interpretation of Article 69 of the European Patent Convention set out above,
which forms part of our domestic law of construction and infringement by virtue
of section 125 of the Patents Act 1977. No construction of the words of this
claim which managed to cover the NIR stent could be said to satisfy the
requirement of a reasonable degree of certainty for third parties."
17. The judge also held that feature H was lacking because the intersecting
bars, if there were any, were not uniform in cross-sectional configuration.
18. Mr Silverleaf QC who appeared for the patentees submitted that the judge
had failed to give an appropriate meaning to the words "intersecting" and
"interconnected" which appear in claim 1. He submitted that the claim should
be read to cover the NIR. He identified the arms of the C members, marked A in
Fig. 1B of Annex II, as the first elongate bars. The joins between them,
marked B, were the second bars. That being so the requirements of the claim
were satisfied in two ways. First, taking Figure 1B of Annex II as a whole,
the second bars B at the extreme right and left side intersected the arms A of
the right and left C members. Second or alternatively the repeating C-shaped
members on the left or right- hand side of Figure 1B had all the features of
claim 1. He accepted that the first bars A were not interconnected (joined) by
two second bars B, but, he submitted, that was not required by the claim. All
that was needed was two first bars intersected by two second bars.
19. The submission of Mr Silverleaf is based upon hope not the words of the
claim. The wire mesh stents depicted in Figures 1A and B of the patent were
prior art and the invention in claim 1 is solely supported by Figures 2A and B
and their associated description. It is therefore to be expected that claim 1
contains features supported by those figures and designed so as to
differentiate the invention from the prior art. It would therefore be
surprising if the claim covered the NIR which is a completely different design
of stent. It does not.
20. Features B and H of the claim require there to be first and second
intersecting elongate members with at least some of the first bars intersecting
with some of the second bars. Thus some of the second bars must cut into some
of the first bars. No such bars exist in the NIR. The ends B of the C-shaped
members do not intersect the arms A. In any case the ends B are not of uniform
cross-sectional configuration as required by feature I. To cut uniform parts
out of them, as suggested, is artificial. Also the claim requires that each
pair of first bars to be interconnected (joined) by at least two bars. It
follows as the judge held that features B, H and I cannot be identified in the
NIR stent.
21. Mr Silverleaf did not suggest that the ambit of claim 1 should be
interpreted more widely than the meaning of the words so as to encompass the
NIR stent. He was right not to do so. The claim has been amended with the
addition of the characterising features H and I. They contain the details of
the invention and limit it to a construction of the type shown in figures 2A
and 2B. The NIR is not of that type.
Palmaz I - Validity
22. The judge held that Palmaz I was not a patentable invention. It was not
new as it had been disclosed by Dr Palmaz to Shiley Inc in 1983 (the Shiley
disclosure) and at a meeting in November 1984 of the Radiological Society of
North America (the RSNA disclosure). The judge rejected the allegation that
the invention was not new having regard to the disclosure in US Patent No.
3657744 (Ersek), but found that the invention was obvious in the light of the
disclosure in that patent and having regard to the admitted disclosures by Dr
Palmaz. In this Court the parties maintained the same position as they had
advanced before the judge. In addition Boston submitted that the patent was
invalid as matter had been added by amendment contrary to section 72(1)(d) of
the Patents Act 1977.
Palmaz I - the Shiley disclosure
23. The Background - Shiley were a Californian company which made heart
valves and other medical devices. In the case of Shiley any obligation of
confidence was excluded by agreement. Thus any disclosure became part of the
state of the art before the priority date of the patent.
24. By 1980 Dr Palmaz had produced a prototype stent made as shown in Figure 1A
of the patent and had expanded it as shown in Figure 1B. He had also written
what was called the 1980 Monograph. It advocated use of a stent as an
alternative to angioplasty. It stated:
"Proposed alternative to balloon dilatation:
The fractured atheromatous material may be contained against the vessel wall
by placing an intraluminal tubular structure which may be expanded at one time
with the stenotic lesion. The tube should be mounted on the balloon and
introduced in the artery with it. Once it is in place the balloon insuflation
would expand the tube and the stenotic lesion together. The tube should have
memory properties so as to oppose the elastic recoil of the wall. The tube
would at the same time, maintain the lumen, avoid dislodgement of atheromatous
material and give structural support to the wall. Theoretical drawbacks
include:
a) Reduction of the longitudinal flexibility of the artery.
b) Thrombogenicity of the prosthetic material.
c) Migration from the point of placement. Limiting the length of the tube to
short segments less than 4 cm may be a solution to the first problem. The make
of the tube has to be related to the modern non-thrombogenic vascular
prosthetic materials. Displacement of the tube from its insertion point may be
prevented by giving the tube either a fenestrated or a corrugated external
surface. The memory of the tube may be obtained by an inner deformable wire
mesh consisting in crisscrossed structure with welded crossing points."
[At this point there appeared the drawings which are appended to this judgment
as Annex III]
"This should be made of silver, tantalum or stainless steel. Several wire
diameters have to be experimented in each wire material so as to establish the
optimum point between resistance to deformity and ability to retain the shape.
The wire mesh is then covered with the vascular prosthetic material which has
to have low thrombogenicity and high radial compliance."
25. Dr Palmaz had had the idea of the slotted tube stent shown in Figures 2A
and 2B of the patent before writing the 1980 monograph. Such as stent was
shown in the right-hand pictures of Annex III but not described in the text.
26. Dr Palmaz approached Shiley and a number of other companies to see if they
would give him a grant and assist him to make prototypes for use in animal
studies. Shiley came to see him at the end of 1982 or the beginning of 1983
and he presented his ideas to them. In February 1983 Shiley said they were not
interested.
27. In April or May 1983 Dr Palmaz telephoned a Mr Bates for help with the
manufacture of the slotted tube stent which is shown in Figures 2A and B of the
patent. He recommended that Dr Palmaz should contact a Mr Schultz who was a
precision engineer. Dr Palmaz went to see him and gave him a copy of the 1980
Monograph. Mr Schultz suggested a number of possible techniques that could be
used including EDM.
28. The Dispute - It was accepted for the purposes of the English
proceedings that the meeting with Shiley was not confidential and that its
purpose was as I have stated. It was also accepted that Dr Palmaz supplied
them with a copy of the 1980 Monograph with the drawings shown in Annex III
depicting the slotted tube construction. It was also accepted that once the
idea of a slotted tube construction was known, the right-hand drawings in Annex
III clearly and unmistakably disclosed all the features of claim 1.
29. The note taken by Shiley does not deal with the form or forms of stent
discussed and the only evidence about the meeting with Shiley was that of Dr
Palmaz. In his witness statement he said that his presentation to Shiley
"concentrated on the wire mesh construction and I do not think that there was
any discussion of the slotted tube". It is clear from his cross-examination
that Dr Palmaz had in March 1998 no clear recollection of what had been said at
the meeting with Shiley about 16 years earlier. Boston submitted that upon the
balance of probabilities the slotted tube had been disclosed to Shiley. That
was disputed by the patentees. Thus the judge had to decide on the balance of
probabilities whether the slotted tube construction was discussed at the
meeting with Shiley.
30. The conclusion - The judge held that Dr Palmaz had disclosed the
slotted-tube embodiment. Having referred to part of the cross-examination of
Dr Palmaz he said:
"The disclosure to Shiley is covered in his cross-examination on pages 175 to
180. At the time of his discussion with Shiley, Dr Palmaz said that the slotted
tube was in his mind as a way of making the product (page 176 line 4). He knew
that a soldered wire construction was difficult to make (page 176 lines 11-12).
He says that he cannot now recall whether he talked about the slotted tube to
Shiley at all (page 176 line 21), and at page 179 he says that he does not now
think that he got to the slotted tube, because he did not know how to make it.
I should at this point say that Dr Palmaz seemed to me to be a very fair
witness. He did his best to deal with what must have been extremely unwelcome
suggestions and I was struck by the fact that he never flatly denied that he
disclosed the idea of the slotted tube to Vascor or to Shiley. His answer at
page 179 line 25 was characteristic. I think that he thought that he might have
disclosed the idea to Shiley, but was not satisfied that he had.
I have to consider the probabilities. These meetings were important in the
pursuit of funds. The silver-soldered wire mesh embodiment was admittedly
difficult to make, and was unattractive because it contained many materials and
was far from uniform, and potentially thrombogenic for this reason. The slotted
tube was uniform. I think that it is much more likely than not that Dr Palmaz
gave these attempts to find funding his best shot. The meetings included a
presentation, and it is normal and natural at such a presentation to explain
everything on the paper or on the slide. I find that Dr Palmaz showed and
described a slotted tube embodiment of his idea to Vascor and to Shiley. Once
the article shown in the picture is described as a slotted tube, it was not
suggested that there was any difficulty in making it (if there were, the
specification, which is silent on the question save to say that the slots are
formed by a conventional etching process, such as electromechanical or laser
etching, would be insufficient) and I find that the slotted tube embodiment of
the 1980 monograph was disclosed as such to Shiley. This disclosure was an
enabling disclosure, and claim 1 as proposed to be amended is anticipated by
this disclosure."
He went on to hold that if the drawings only, without explanation, had been
shown to Shiley, the idea of a slotted tube was not clearly and unambiguously
disclosed.
31. Mr Silverleaf reminded us that the burden of proof was on Boston and that
they had called no evidence. He took us to the totality of Dr Palmaz's
evidence as to what happened at the meeting with Shiley which is contained in
his witness statement and in his cross-examination. He also reminded us that
the 1980 Monograph had not been updated to include a written description of the
slotted-tube embodiment until about 9 months after the meeting with Shiley. He
submitted that the evidence, when read as a whole, contained no basis for the
judge's conclusion that Dr Palmaz had described the slotted-tube embodiment to
Shiley. Although Dr Palmaz was accepted to be a truthful and fair witness the
judge had failed to pay proper regard to the effect of his evidence namely that
he did not think he had disclosed the slotted tube, but he could not be
absolutely certain.
32. Mr Kitchin QC, who appeared for Boston, reminded us of the background to
the meeting. The wire mesh stent was difficult and time consuming to make; Dr
Palmaz had the idea of the slotted tube by 1980; it was shown in the 1980
Monograph; the purpose of the meeting was to obtain money and help with the
manufacture of prototypes. He then drew to our attention that Dr Palmaz had
had discussions with other companies for the same purpose as the discussions
with Shiley, in particular in 1982 with another company called Vascor. During
those discussions he showed Vascor a slide of both the woven and slotted tube
stents. He was asked about what had happened at Evidence I page 162:
"Mr KITCHIN: [Q] What I would like to ask you is, so far as you were
concerned, when you were presenting this to those gentlemen, you considered
that these pictures were perfectly descriptive of your idea.
A. Yes. They were for me. I drew them myself.
Q. And you apprehend that, in showing those slides, you were perfectly
describing both the wire mesh version and the slotted tube version of your
device.
A. Yes, in addition with the text, sure, and my explanations at the time.
This was a meeting.
Q. Do you recall what you said to them at the time?
A. No, I cannot, not specifically."
33. What had happened at the meeting with Vascor was, Mr Kitchin suggested, the
natural and obvious course for such a discussion to take. Dr Palmaz wanted
help to continue his development and to produce prototypes. It was in his
interest to describe all his ideas and, Mr Kitchin submitted, he must have
discussed both of his ideas with Shiley, just as he had done with Vascor. That
was put to Dr Palmaz during his cross-examination.
34. I have re-read the evidence of Dr Palmaz and believe that, taking into
account the background to the meeting with Shiley and its purpose, there was
ample evidence to support the judge's conclusions. Also, I am conscious that
he had the advantage of seeing Dr Palmaz give his evidence. I have therefore
come to the conclusion that the judge's finding that the slotted tube
construction was disclosed to Shiley should be upheld with the result that
Palmaz I lacks novelty and is invalid.
Palmaz I - The RSNA Presentation
35. The Background - In November 1984 Dr Palmaz gave a short
presentation of 5 to 10 minutes, perhaps 8 minutes, to about 40 members of the
Radiological Society of North America. He accepted that it was a public
disclosure and that at the meeting he showed slides, one of which showed the
drawings depicted in Annex III.
36. By November 1984 Dr Palmaz had met Mr Schultz and obtained from him ideas
as to how the slotted tube stent could be manufactured. To reflect that
knowledge, the 1980 Monograph had been altered in 1983 to describe both
configurations. It stated:
"The first configuration could be fabricated out of silver, tantalum or
stainless steel wire. Several wire diameters have to be tried to establish the
optimum point between resistance to deformity and ability to retain shape. The
cross points of the helical and antihelical wire coils should be welded in the
expanded state and then the tube should be coated with teflon and heparin using
the standard methods employed for vascular guide wires manufacturing. The tube
should be compressed, mounted over a modified balloon angioplasty catheter with
guards to protect the graft leading and trailing ends while the assembly is
advanced within the skin.
...
The second configuration is basically similar. The tube could initially be a
thin walled silver, tantalum or stainless steel continuous tube in which
alternating fissures such as shown in Fig. 1 [Annex III] have been done. This
process may require sophisticated techniques such as electronic or laser
etching. After expansion, the unfolded "bars" between fissures will twist and
loss of length will result. Although the expanded tube wall will be thicker
than the wire mesh tube the unexpanded tube will be smoother and thinner
therefore allowing an easier introduction and positioning before inflation.
After testing either or both configurations for mechanical behavior, stability
and biocoapatibility a second phase of development should involve coating of
the tubes with porous polyurethane or other biologically inert plastic."
37. The Dispute - Dr Palmaz in his witness statement stated that at the
presentation it was likely that the Annex III slide was shown and that he had
described the woven wire stent and its use. However he said - "During my
presentation I did not mention the other stent (the one on the right-hand
side). I discussed only the woven wire stent".
38. The judge held:
"Accordingly, by the time of the RSNA presentation, Dr Palmaz had himself
written a description of both embodiments illustrated in the figure. Boston
relies upon a short passage in a deposition of Dr Palmaz taken in proceedings
in the United States, which was put to him in cross-examination at page 196
line 11 to 197 line 26. I think that it is established that Dr Palmaz made a
short presentation at the RSNA meeting in question and made use of the slide
during the presentation. The purpose of the presentation was to show colleagues
what his ideas were and how far they had come. The presentation was one of many
at the meeting in question, and was short (Dr Palmaz said about five minutes,
and the summary, to be found at X1 tab 1, suggests that with questions the
whole presentation took eight minutes). The summary begins as follows:
"In an attempt to overcome the problem of restenosis after vascular balloon
dilatations, we have developed an expandable intraluminal graft that allows
dilatation of the lesion and simultaneous placement of a supportive
endoprosthesis to prevent recoil of the arterial wall. The graft is made of
continuous, woven, stainless steel wire with soldered cross points. The
resulting tubular mesh has a wall thickness of 20-45 microns and a 98% open
surface ... "
Obviously there is no mention of a slotted tube. The question is again whether
Dr Palmaz explained the slide which he certainly presented, and whether that
explanation included a mention of a slotted tube and, if it did not, whether a
slotted tube was either clearly and unambiguously disclosed by the slide itself
or an obvious interpretation of the slide.
In my judgment, it is much more likely than not that Dr Palmaz explained his
slide by explaining what both the embodiments which it depicts were.
Accordingly I find that he again disclosed the slotted tube as such at the RSNA
meeting. If I am wrong about this, I am satisfied, for the reasons which I have
already given, that a slotted tube is an obvious interpretation of the figure."
39. Mr Silverleaf submitted that the judge's conclusion was contrary to the
evidence of Dr Palmaz contained in his witness statement which had not been
disputed in cross-examination. The purpose of the presentation was to explain
to his peers what he had achieved, not his ideas for the future. It followed
that there was no reason why he should tell them about the slotted tube stent
which had not at that time been made.
40. Mr Kitchin submitted that there was ample evidence for the judge's
conclusion. By the time of the presentation the 1980 Monograph had been
updated to include a description of the slotted tube stent and Dr Palmaz knew
how it could be made. He also knew that the woven stent was difficult to make
and complicated in use. On more than one occasion Dr Palmaz had made clear in
his evidence that he could not remember the detail of what had happened about
16 years earlier. That was apparent from his evidence as to whether he showed
the Annex III slide. He said:
"As I said, I showed the stent. .... This is about almost 20 years ago. I
had the impression, it is a possibility that I did show this slide because
there were very few drawings of the stent in general and there is a possibility
that I did show it because it comes straight from the 1980 Monograph."
41. There was, Mr Kitchin submitted, no reason why Dr Palmaz should not
disclose both types of stent. In fact he had every reason to do so. As he
said in cross-examination "It was his intention to explain his invention to the
world."
42. The conclusion - There was no written record of the presentation
which took place in 1984 and it was improbable that Dr Palmaz could have had a
reliable memory as to the detail of what was said. The judge therefore had to
decide whether, upon the balance of probabilities, Dr Palmaz had disclosed the
slotted tube stent taking into account the surrounding circumstances, the
evidence of Dr Palmaz and the impression he gained of him when he gave his
evidence.
43. There was sufficient evidence for the judge to form the view that he did
and in my view this Court should not interfere with the finding of fact by the
trial judge that the slotted tube version was disclosed. It follows that the
patent is invalid as it lacks novelty having regard to the RSNA presentation.
Palmaz I - Obviousness: the Palmaz disclosures
44. It is artificial to go on to consider obviousness in the light of the
conclusion that the invention was disclosed. As the matter was argued at
length I will do so, but must assume that no anticipating disclosure was made.
45. The judge held that the admitted disclosure of the Annex III drawings did
not amount to a clear and unmistakable disclosure of a slotted tube stent.
Despite the submission of Mr Kitchin to the contrary, I agree. The judge went
on to hold that it was obvious that the right-hand drawings in Annex III showed
a slotted tube device and also that it was obvious to move from a woven wire
arrangement to a slotted tube arrangement as claimed in claim 1. That
patentees submitted that he was wrong.
46. Mr Silverleaf reminded us of the need to avoid ex post facto analysis. As
Lord Russell said in Non-Drip Measure Co Ltd v Strangers Ltd [1943] 60
RPC 135 at 142:
"Whether there has or has not been an inventive step in constructing a device
for giving effect to an idea which when given effect to seems a simple idea
which ought to or might have occurred to anyone, is often a matter of dispute.
More especially is this the case when many integers of the new device are
already known. Nothing is easier than to say, after the event, that the thing
was obvious and involved no invention. The words of Moulton LJ in British
Westinghouse v Braulik [27 RPC 209 at p.230] may well be called to mind in
this connection: 'I confess (he said) 'that I view with suspicion arguments to
the effect that a new combination, bringing with it new and important
consequences in the shape of practical machines, is not an invention, because,
when it has once been established, it is easy to show how it might be arrived
at by starting from something known, and taking a series of apparently easy
steps. This ex post facto analysis of invention is unfair to the
inventors, and, in my opinion, it is not countenanced by English patent law
...'".
47. Of course, it was evident that to those who know of the invention that the
right-hand drawings in Annex III showed a slotted tube stent. Once you see it
in that context you cannot think of it as being anything else. But that, Mr
Silverleaf submitted, was not the correct approach. Obviousness had to be
judged as of November 1985 at a time when and on the assumption that the
slotted tube stent had not been disclosed. He submitted that at that time the
natural inclination of the skilled man was to believe that the right-hand
drawings showed another example of a soldered arrangement, but with thicker
wire. He drew to our attention the state of the art in 1985. At that time the
work on stents was in its infancy. There were a number of techniques being
considered to deal with stenosis and restenosis, other than stents, such as
laser therapy, hot tip probes and cutting devices used to remove tissue. He
submitted that the invention was not obvious as the skilled man would not
realise that the device, the stent shown in Annex III, was worth pursuing and
in any case he would not look for a deficiency in the woven wire stent which
needed to be improved. Thus the attack on obviousness failed at the outset
without the need to appreciate what were the differences between the prior art
and the invention and then consider whether the differences were obvious.
48. I reject that approach. There is but one question to be asked. Was the
invention as claimed obvious having regard to matter that formed part of the
state of the art? As Oliver LJ made clear in Windsurfing International Inc
v Tabor Marine (Great Britain) Ltd [1985] RPC 59, it is necessary to assume
that a skilled man considers the pleaded prior art with interest and "is at
least sufficiently interested to address his mind to the subject and to
consider the practical application of the information which he is deemed to
have". He also pointed out that "What has to be determined is whether what is
now claimed as inventive would have been obvious, not whether it would have
appeared commercially worthwhile to exploit it". Also as Laddie J said in
Brugger v Medic-Aid Ltd [1996] RPC 635 at 651 line 6:
"First a route may still be an obvious one to try even if it is not possible to
be sure that taking it will produce success, or sufficient to make it
commercially worthwhile. The latter point is inherent in Johns-Manville
Corporation's Patent [1967] RPC 479, a decision of the Court of Appeal
under the Patents Act, 1949 which is just as relevant to obviousness under the
1977 Act. Secondly, if a particular route is an obvious one to take or try, it
is not rendered any less obvious from a technical point of view merely because
there are a number, and perhaps a large number, of other obvious routes as
well. If a number of obvious routes exist it is more or less inevitable that a
skilled worker will try some before others. The order in which he chooses to
try them may depend on factors such as the ease and speed with which they can
be tried, the availability of testing equipment, the costs involved and the
commercial interests of his employer. There is no rule of law or logic which
says that only the option which is likely to be tried first or second is to be
treated as obvious for the purpose of patent legislation."
49. I remain of the view that the best way to arrive at the right conclusion
was that adopted by the judge, namely the structured approach suggested by
Oliver LJ in Windsurfing at page 73:
"There are, we think, four steps which require to be taken in answering the
jury question. The first is to identify the inventive concept embodied in the
patent in suit. Thereafter, the court has to assume the mantle of the normally
skilled but unimaginative addressee in the art at the priority date and to
impute to him what was, at the date, common general knowledge in the art in
question. The third step is to identify what, if any, differences exist
between the matter cited as being "known or used" and the alleged invention.
Finally, the court has to ask itself whether, viewed without any knowledge of
the alleged invention, those differences constitute steps which would have been
obvious to the skilled man or whether they require any degree of invention."
50. The inventive concept is a stent having features H and I of claim 1. In
essence it is a slotted tube stent.
51. By 1985 the idea of stents was known as was the woven wire stent shown in
Figures 1A and B of the patent. The notional skilled man, a medical parts
manufacturer, would have or have known about machines capable of cutting slots
in tubes to make a slotted tube stent. He would also know about angioplasty
and the drawbacks that had been encountered, in particular restenosis. I have
no doubt he would realise that there was a need to develop procedures and
devices of which stents would be one.
52. The judge considered obviousness upon a number of alternative bases and
upon assumptions that he had been wrong on conclusions he had reached. I do
not believe it necessary to deal with all the arguments and therefore confine
my judgment to the attack based upon the disclosure of Annex III either in the
monograph or in slides upon the assumption that the slotted tube construction
was not clearly disclosed. Upon that assumption the difference between the
prior art and the inventive concept is the realisation or the idea of making a
stent as shown from a tube.
53. The judge held that a slotted tube was an obvious interpretation of the
right-hand drawings of figure 1. In my view he was right. Anybody looking at
Annex III would realise that two configurations were being shown. In expanded
form they had a similar diamond configuration, but when unexpanded they were
very different. As Professor Cumberland pointed out, it looks to be a
different structure, namely a tube. That would in my view be an obvious
interpretation which would be supported by the common general knowledge of the
skilled man as to the way it could have been made. It may be that he would
contemplate that the elongate members could have been soldered, but the slotted
tube idea would have been an obvious interpretation.
54. The judge came to the right conclusion for the right reasons. The patent
was obvious having regard to the disclosure of the drawings in Annex III.
Palmaz I - US Patent No. 3657744 (Ersek)
55. Ersek was published in 1972. The relevant figures are appended to this
judgment marked Annex IV. A tubular sleeve 16 is produced as shown in figures
2 and 3 by making slits in an impervious metal tube. The tube is used as a
fixation prosthesis device in, for example, humans. As shown in Figure 1 it
helps to connect the iliac arteries 13 and 14 to the aorta 11. This is
achieved by inserting the expandable tube 16 into the artery and using the tool
shown to expand it so as to force the fenestrations of the sleeve into the wall
of the aorta. The specification describes the tube in this way:
"The tubular sleeve 16 is made of deformable material such that it retains its
expanded dimensions after expansion [is] in place. It is formed from a
non-toxic material compatible with blood and other bodily fluids, such as
stainless steel. Its walls desirably have a large percentage of open area as
to permit proliferation of the intima of the vessels thorough the openings and
over the intervening strand-like or ribbon-like members. Preferably the
openwork sleeve is formed from so-called "expanded metal" sheeting which is
produced by forming a series of staggered parallel slits in an impervious metal
sheet and then stretching the sheet in a direction perpendicular to the slits
to open the slits into apertures and expand the metal sheet in that direction
while contracting it slightly in the opposite direction. The stretching
operation by which the metal sheet is expanded imparts a twist or bend to the
undulating flat ribbon-like portions 22 of the sheet metal separating the
diamond-shaped apertures 23 which are generally uniformly sized and
distributed. This twisting or bending of the metal members 22 between adjacent
apertures imparts and angle or direction to the apertures themselves and to the
ribbon-like members."
56. The judge rightly held that Ersek did not anticipate claim 1 as there were
no intersecting members. Mr Kitchin did not challenge that conclusion if claim
1 had the meaning that I believe it has. He supported the finding by the judge
of obviousness.
" The only difference of substance between the claimed invention and the
disclosure of Ersek lies in feature I. Thus, if it would be obvious to make the
slots or slits in Ersek's starting material of sufficient width that it would
be possible to identify circumferential members, the claim is bad. As I have
indicated, I find no clear disclosure in Ersek of such members, but it seems to
me that to vary the width of the slots is pre-eminently the making of a mere
workshop variation, and slots of any substantial width will result in the
presence of circumferential members. Claim 1 is obvious in the light of Ersek,
but claim 3 is not. Ersek's delivery and expansion apparatus does not render
balloon expansion obvious."
57. Mr Silverleaf submitted that the judge had failed to notice that the Ersek
members were not the same width in all directions and therefore not of uniform
thin cross-section. I accept that he did not mention the difference in shape,
but his conclusion cannot be faulted on that basis as the members are thin and
uniform in cross-section. The main attack upon the judgment was based upon the
emphasis in Ersek as to the way the elongate members twisted upon expansion to
provide secure fixing. Ersek, it was said, was a paper proposal which was not
suitable for use as a stent as the twists would injure the vessel walls during
insertion. In fact the configuration shown would be undesirable. It would not
be obvious to modify Ersek by changing the slits to slots to produce second
intersecting members as to do so would tend to remove the twist.
58. It is important to realise that claim 1 is not limited to a stent intended
for percutaneous insertion. Further, it encompasses stents which twist on
expansion. The sole difference between the inventive concept of claim 1 and
the disclosure in Ersek is the provision of second bars as required by feature
I. Those would be produced by cutting slots instead of slitting the tube. Was
that an obvious modification in 1985?
59. There is force in the submission that the skilled man would not in the
1980's have believed it obvious to modify the method of making Ersek, which had
been proposed eight years earlier, by using slots. However I am conscious of
the observation of Lord Hoffmann in Biogen Inc v Medeva Plc [1997] RPC 1
at page 45:
"Where the application of a legal standard such as negligence or obviousness
involves no question of principle but is simply a matter of degree, an
appellate court should be very cautious in differing from the judge's
evaluation."
60. In my view, the judge approached the issue correctly and there is a sound
basis for his conclusion which should be upheld.
Palmaz I - Added Matter
61. The judge held that the specification, if amended as requested, would be
invalid because the matter disclosed would extend beyond that disclosed in the
application (see sections 72(1)(d) and 76(2)). The EPO which allowed the
amendments came to the contrary view. As I have concluded that the patent is
invalid on other grounds, there is no need to decide which view on this issue
is correct and I decline to do so.
Palmaz II
62. Palmaz II claims priority from a US application filed on 28th March 1988.
It follows that the application for Palmaz I is part of the state of the art.
The invention in general terms relates to expandable intra-luminal grafts of
the type disclosed in Palmaz I joined together by flexible connecting members.
63. After referring to the prior art the specification comes at column 3 line
17 to the problem which the invention seeks to deal with.
"For repairing blood vessels narrowed or occluded by disease, or repairing any
other body passageways, the length of the body passageway which requires
repair, as by the insertion of a tubular prosthetic graft, may present problems
if the length of the required graft cannot negotiate the curves or bends of the
body passageway through which the graft is passed by the catheter. In other
words, in many instances, it is necessary to support a length of tissue within
a body passageway by a graft, wherein the length of the required graft exceeds
the length of a graft which can be readily delivered via a catheter to the
desired location within the vascular system. Some grafts do not have the
requisite ability to bend so as to negotiate the curves and bends present
within the vascular system, particularly prostheses or grafts which are
relatively rigid and resist bending with respect to their longitudinal axes."
64. There follows the consistory clauses and a description of the figures.
Figures 1A and B are the same as Figures 2A and B of Palmaz I (see Annex I).
The invention is illustrated by Figures 7 to 10 which are Annex V to this
judgment. Figure 7 shows the graft in unexpanded form. It consists of 3
elements of the type shown in Palmaz I joined by connecting members 100.
Figure 9 shows the form the graft will assume when delivered to the desired
location within a curved portion of a body passageway. Figure 10 shows the
graft expanded.
65. Claim 1 broken down and lettered for convenience is as follows:
"A An expandable intraluminal graft, or prosthesis (70) comprising:
B at least one thin-walled tubular member (71) having first and second
ends (72, 73) and a wall surface disposed between the first and second ends,
the wall surface having a substantially uniform thickness
C and a plurality of slots (82) formed therein, the slots (82) being disposed
substantially parallel to the longitudinal axis of said tubular member (71);
D the tubular member (71) having a first diameter which permits
intraluminal delivery of the tubular members into a body passageway (80) having
a lumen (81);
E and the tubular member having a second, expanded and deformed
diameter, upon the application from the interior of the tubular member of a
radially, outwardly extending force, which second diameter is variable and
dependent upon the amount of force applied to the tubular member (71) whereby
the tubular member (71) may be expanded and deformed to expand the lumen of the
body passageway,
F characterised in that the vascular graft or prosthesis (70) comprises a
plurality [of] tubular members (71) and at least one connector member (100)
being disposed between adjacent tubular members to flexibly connect adjacent
tubular members."
Palmaz II - infringement
66. The NIR stent alleged to infringe is illustrated in Annex II. The
patentees identified the U-shaped parts marked C in Figure 1B of Annex II as
connecting members as required by feature F. It followed that the tubular
members referred to in that feature and of course features B, C, D and E were
made up of the components either side marked A and B in Annex II.
67. Boston, rightly in my view, submitted that the NIR was one flexible tubular
member not a plurality joined by a connector as required by feature F. As the
judge said:
" In my view, it is straining language to describe what is essentially a wavy
ring as a tubular member having a wall surface of substantially uniform
thickness, but whether that is right or not, I am firmly of the view that the
ring of C-shaped members is not geometrically an object satisfying feature C of
the claim. What is not present is a member in which the slots are formed and
which is connected to the adjacent tubular member by a connector member."
68. Mr Silverleaf relied upon the evidence of Dr Clyne in paragraph 5 of his
witness statement and of Dr Buller in paragraphs 130 to 132. That evidence is
not persuasive. It amounts to an artificial exercise which splits up the NIR
into tubular members when they do not exist. Professor Cumberland's view
expressed in paragraphs 82 to 85 of his witness statement was correct. The
judge was right.
69. Mr Silverleaf did not suggest in this Court that there could be
infringement if the NIR did not fall within the wording of claim 1.
Palmaz II Validity - Obviousness
70. The primary attack was based upon the disclosure of Palmaz I- type stents.
At the priority date of Palmaz II, angioplasty was a recognised procedure.
However the use of stents was in its infancy and the published work only
described use in animals. The judge held and his conclusion was not
challenged, that Palmaz I stents were not common general knowledge, but some
workers in the field were aware of the work that was being done with them.
71. The inventive concept of Palmaz II is the use of flexible connectors
between Palmaz I-type stents. Were such connectors obvious at the priority
date?
72. Pleaded as prior art was an article by Dr Palmaz published in Radiology
in July 1985. It described his work. At page 75 the article said:
"A unique feature of the expandable mesh tube is its ability to dilate an area
of stenosis while being implanted; therefore, the amount of time required to
implant an expandable graft is similar to that required for regular balloon
angioplasty. After maximal inflation, the balloon can immediately be deflated
because the mesh opposes elastic recoil. Since the extent of endothelial
destruction seems to be a function of balloon inflation time (12), the vessel
endothelium would largely be spared because 80% of the expandable graft is open
surface. The surprisingly rapid covering by endothelium of our wire-mesh graft
is probably due to intact patches of endothelium of our wire-mesh graft is
probably due to intact patches of endothelium left between the wire segments
that proliferate and bridge over the mesh. This finding is in contrast with
covering by endothelium of synthetic grafts in dogs, which takes about 5 months
to be completed (13). The inner surface of healed synthetic grafts in humans
is covered by fibrin and does not become covered by endothelium (14).
Patency of side branches arising at the level of the graft was observed on
angiograms and was confirmed histologically. Considering the large proportion
of open surface in the graft, these findings were not unexpected. However,
this attribute of the wire-mesh graft is a potential advantage over tightly
wound coil-spring or solid grafts.
One disadvantage inherent in this graft configuration is the lack of
longitudinal flexibility, which limits its use to straight arterial segments
or, in the case of curved arteries, requires the use of short graft lengths.
In two of our experiments (grafts 3 and 5), an excessively long graft caused
kinking and immediate thrombosis. This problem was later solved by using
shorter grafts or grafts in tandem. Another potential problem is that
excessive radial compliance mismatch at the point of transition between artery
and graft may cause sheer stress and neointimal proliferation. Nevertheless,
we have not observed this occurrence in our dogs up to 8½ weeks following
the procedure. In fact, electron microscopic studies at the area of transition
showed no endothelial alteration, nor was any prominent myointimal
proliferation present on light microscopy."
73. As Dr Palmaz pointed out, rigidity could require grafts to be used in
tandem. There were two ways that they could be inserted prior to expansion:
either they had to be placed one after the other with the obvious disadvantage
of having two insertions or two stents had to be mounted on one balloon. The
second alternative would require accurate placement of both stents relative to
each other. How could that be done? The most obvious way was to connect them
together by a flexible connection. That was the view of the judge. He
said:
"To implant stents in tandem they are either loaded on a single balloon and
expanded simultaneously, or they are successively introduced, the catheter
being withdrawn and reinserted. The latter alternative is very unattractive if
it can be avoided, since it means passing the balloon twice. There was
considerable evidence that stents can be detached from the balloon in the
course of the procedure. Dr Palmaz accepted it under cross-examination (pages
237-239) and Professor Cumberland in chief at 1068-1070.
I was left with the strong feeling that this issue was made to appear more
complicated than it really was. Such a feeling is a snare when considering
obviousness, and I have gone over the evidence again to satisfy myself that it
was not unjustified. It is desired to introduce two short stents, rather than
one long one, because the long stent is inflexible. Thus, the two short stents
will lie in the artery at an angle to each other, so as more nearly to
accommodate the curve. At the same time, the two stents should not be inserted
sequentially, if that can be avoided, and they should be prevented from
detaching themselves from the balloon. They are difficult to position being
very small (one-half an inch or less long) and difficult to see by X-ray
fluoroscopy, and inserting two one after the other also doubles the difficulty
of positioning them, which is already great. (In this context, I should say how
greatly impressed I was by the recordings of some procedures carried out by Dr
Buller which I was shown.) It seems to me that a single flexible tie of some
description between the two stents, so as to help them to be correctly
relatively positioned, is absolutely obvious.
The patentees' answer to this was a number of ex post facto reasons for not
taking the step. The only one of any substance was that a flexible connector of
any sort would be perceived as objectionable, since it added to the
thrombogenic potential of the stent. I regard this as a surprising contention
given the relative size of the grafts and any potential joint - see Professor
Cumberland in chief at 1071. There was no dispute that one obvious way of
linking the two short grafts would be to use a short strut."
74. Mr Silverleaf contended the conclusion reached by the judge was the result
of hindsight. The inventive idea behind claim 1 was the recognition of the
need for flexibility of the stents during delivery coupled with rigidity after
expansion. There was, he submitted, no recognition in the art of how that
could be done until after the invention of Palmaz II was made. That submission
disregards the obvious step of connecting two stents together where, as
suggested in the prior art, they needed to be used in tandem. Once use in
tandem was found to be necessary, then flexible connection was obvious as the
judge said. That view was supported by the evidence of Professor Cumberland
(Evidence 7 page 1067 to 1071) which was not challenged in cross-examination.
Dr Buller said that he would not connect two stents together as he would not
want to use more metal than was necessary. In theory he may be right, but that
does not make the use of a connector inventive. It was an obvious alternative
which could be used.
75. The judge also concluded that claim 1 was obvious in the light of certain
publications describing the Gianturco stents. They show use of connectors and
support the conclusion that connectors were obvious, but are not as close to
claim 1 as the Palmaz prior art.
Palmaz II - claim 3
76. Claim 3 is apendant to claims 1 or 2. It requires at least one connector
member to be disposed co-planar with each tubular member and non-parallel to
the longitudinal axis of the tubular member. Although Mr Silverleaf maintained
independent validity of claim 3 as apendant to claim 1, he failed to advance
any cogent argument in support. The judge's conclusion on this matter cannot
be faulted.
"Claims 2 and 3 of Palmaz II are said to be independently valid. Claim 2
requires the connecting strut(s) to be out of parallel with respect to the
longitudinal axis, and claim 3 requires the struts to be coplanar (an
inappropriate word) with the tubular member. I believe that this means that
they should lie in the same cylindrical surface of the wall of the tubular
member. Increasing the non-parallelism of the connecting struts increases the
flexibility of the connection over the same number of struts parallel to the
axis. This is obvious. Professor Cumberland gave evidence that he considered
such an expedient to be obvious from first principles: see paragraphs 87-90 of
his report. I do not believe that these passages were challenged directly in
cross-examination. In any event, they seem to me merely to reflect common
sense. I cannot conceive that the connector strut(s) would be positioned out of
the common cylindrical surface. Accordingly I consider that claims 2 and 3 are
invalid for obviousness also."
Conclusion
77. This appeal should fail. The judge was in my view right that the patents
were not infringed and were invalid.
LORD JUSTICE HENRY:
78. I agree.
Order: Appeal Dismissed European patents revoked. Appellants to pay
Respondents 95% of their costs of this appeal and the Respondents appeal and
the respondents notice, such costs to be assessed if not agreed.
(order does not form part of the approved judgment)79. ANNEX I80.
ANNEX II
NIR Stent - unexpanded
Fig. 1A
Fig. 1B
81. ANNEX II (cont.)
NIR Stent - expanded
Fig. 2
82. ANNEX III83. ANNEX IV84. ANNEX V
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