The patent relates to an apparatus for restoring blood flow in occluded blood vessels, particularly occluded cerebral arteries.
The important feature relates to “a connection point (9), at which the tapering portion converges, located at a proximal end (3) of the tapering portion, the tapering portion permanently attached to the push or guide wire (7) at or adjacent to the connection point (9)”;
The flow is restored in that an opening is created next to the thrombus and once the opening is created, the thrombus is pulled away.
Brief outline of the procedure
The OD rejected the opposition and the opponent appealed this decision.
The board held that claim 1 as granted was lacking N over D4=US 2005/0209678 (1st X in ISR/EPO).
The discussion of whether or not D4 was novelty-destroying for the subject-matter of claim 1 focused on the question of whether D4 disclosed a permanent attachment of the tapering portion to the push or guide wire.
It was undisputed that the remaining features of claim 1 were disclosed in D4.
The opponent’s point of view
The present patent did not include a definition of the term “permanent attachment”, which was used only one single time (column 5, lines 17 to 18) without any further explanations.
The device of D4 was suitable for removal of a thrombus in a blood vessel, as acknowledged by the present patent. In order to be used for this purpose, the guide wire had to be permanently attached to the implant such that tractive and shear forces could be transmitted. If this were not the case, it would not be possible to move the device of D4 back into the catheter, as mentioned in paragraphs  and .
The connection between the guide or push wire and the mesh structure according to D4 could be detached by applying electrical energy to an electrolytically corrodible separating element. Releasing this attachment required additional measures and equipment, in particular a power source and an electrode, which was to be placed on the surface of the body.
Hence, the connection between the guide wire and the stent of D4 was permanent for as long as these additional measures were not taken and no electric current was applied to the connection. When using a device as claimed or as described in D4 for removal of a thrombus it was not necessary to connect a power source for electric current to the separating element or to place an electrode on the surface of the body. Hence, during the whole procedure of thrombus removal the connection between the guide wire and the device would be unaffected and would remain intact. Therefore, the connection had to be considered to be permanent.
For the opponent, “permanent” could not be regarded as contrary to “releasable“.
The proprietor’s point of view
D4 disclosed a medical implant that was introduced into the vasculature by a guide wire. Since the implant had to stay inside the body of the patient, it was essential for the connection between the guide wire and the implant to be detachable (paragraphs  and ).
The literal meaning of “permanently attached” was that the parts were attached in a permanent manner, i.e. the attachment was configured to last forever without already including means for ending it. Unlike the releasable attachment of D4, a permanent attachment was not configured – if used for the intended purpose – to be released.
The person skilled in the art was aware of the distinction between permanent and releasable attachments, as – in the technical field of treating blood vessels – releasable devices were known requiring means for disconnecting the treatment device (stent) from the positioning device, i.e. the guide wire and, in contrast, permanently attached devices not comprising such disconnecting means were also known.
The meaning of “attached” and different ways of attaching the treatment device to the positioning device were disclosed in the prior art, distinguishing between permanent and releasable attachments.
Moreover, using “permanently” together with “attached” only made sense if the term “permanently” further specified the properties of the attachment such that certain attachments were thereby excluded.
For the proprietor, the description of the patent defined the terms “permanent” and “releasable” as mutually exclusive. In the patent it was stated that the connection in D4 was releasable, while the connection according to the invention was described as permanent.
Furthermore, the releasable connection shown in Figures 19a and 19b was disclaimed as not in accordance with the invention. On page 7, lines 25 to 26, the application as originally filed distinguished between a permanent attachment and a non-permanent attachment, which included means for releasing the connection. The statement in paragraph  that the drawings “illustrate exemplary embodiments of the invention” did not apply to these figures.
If the connection contained means for releasing the attachment, such as in D4, the connection would last until the user activated the means for releasing the attachment, i.e. not necessarily forever. Therefore, this was not a permanent attachment, but a releasable attachment, which did not fall under claim 1.
Moreover, the term “permanent” was not used in D4 for the connection between the stent and the guide wire.
Request for a referral to the EBA
In view of T 1473/19, taken by the present board in a different composition, the proprietor requested that the following questions concerning claim interpretation be referred to the EBA.
1. When interpreting a claim for assessing its compatibility with Article 54 EPC (Novelty) and the parties have presented (at least) two distinguishing alternatives, could the Board select one of these alternatives without any evidence?
2. In case that the originally filed application contained disclosure for two alternatives, the applicant selected one of the two alternatives to limit the claim and deleted the non-selected alternative to align the description with amended claims, is it a reasonable claim interpretation that the term used for the selected alternative is interpreted to cover also the non-selected alternative?
3. In case that neither the description nor the drawings of the granted patent contain support for one of the alternatives, would a prior art document of an unrelated applicant form evidence for the understanding of the person skilled in the art in the relevant technical field?
The board’s position
It is undisputed that D4 discloses a mesh structure forming a medical implant (stent) 1 with a tapering portion that is connected to a guide wire 21 (Figure 5), and that the mesh structure is suitable to engage at least a portion of the thrombus to form a removable, integrated apparatus-thrombus mass. It is mentioned in paragraphs  and  of the present patent that the apparatus of US 7,300,458, which is the granted patent to published application D4, may be employed for the methods described in the patent.
According to the established case law, patent claims must be interpreted through the eyes of the person skilled in the art, who should try – with synthetical propensity – to arrive at an interpretation of the claim which is technically meaningful and takes into account the whole disclosure of the patent (see Case Law of the Boards of Appeal, 10th edition 2022, II.A.6.1, first paragraph).
In the present case, both parties took the description of the patent into account to arrive at their differing interpretations of the expression “permanently attached“. This is in line with the approach taken by the present board in a different composition in decision T 1473/19, Reasons 3.15, commented in the present blog, according to which the principles of claim interpretation as set out in Art 69 and Art 1 of the Protocol on the Interpretation of this provision are to be applied in proceedings before the EPO.
Claim 1 itself neither defines nor specifies the term “permanently attached” further, either in terms of constructional features or in terms of the conditions under which the attachment is maintained. This matters insofar as the primacy of the claims under Art 69(1), first sentence, limits the extent to which the meaning of a certain claim feature may be affected by the description and the drawings, cf. T 1473/19, Reasons 3.16.1.
In the board’s view, the person skilled in the art understands the term “permanently” in claim 1 as characterising the attachment of the tapering portion of the implant to the push or guide wire with regard to how long this attachment will last. Therefore, this feature is arguably limiting to the extent that it requires the attachment to last a certain amount of time. However, the required duration or durability of the attachment is not specified further anywhere in the patent, either in the claims or in the description.
The board opined that in the physical world, nothing lasts forever in its current form. Furthermore, a physical connection can always be detached if an appropriate external force is applied.
The board construed the term “permanently” in claim 1 to mean that the attachment must last long enough to allow reliable extraction of a thrombus by pulling on the guide wire.
Contrary to the proprietor’s allegation, this meaning does in the board’s view not already follow from the word “attached” itself, since it is possible – if a use according to the patent is not intended – to realise an attachment that does not last long enough to allow reliable extraction of a thrombus by pulling on the guide wire.
However, even if the meaning as described above already followed from the word “attached” itself, it would not change the board’s interpretation of claim 1, as it is – contrary to the proprietor’s assertion – quite possible that a certain word in a claim does not have any limiting effect of its own.
The catchword of the decision reads as follows:
“Under Article 69(1) EPC the description and the drawings can only be used for interpreting features which are already present in the claims, but not for adding further – positive or negative – claim features or for replacing existing claim features by others (Reasons 2.15).
The application as filed usually cannot provide guidance for interpreting the claims of the patent as granted (Reasons 2.16).
A board of appeal is not limited to the claim interpretations advanced by the parties but may also adopt a claim interpretation of its own (Reasons 3.4.2).
Relying on documentary evidence is not a precondition for the adoption of a certain claim interpretation by a board of appeal (Reasons 3.4.3).
Request for a referral to the EBA
The request for a referral was dismissed by the board.
Without going much into details, the board held that the first question suggested by the respondent appeared to be based on several erroneous assumptions. In its reply the board referred to T 1473/19.
For the board, the second question does not concern a “point of law of fundamental importance” within the meaning of Art 112(1), which would be “relevant to a large number of similar cases“. In addition, the assertion that “the applicant selected one of the two alternatives to limit the claim” indicates that the second question starts from the assumption that claim 1 as granted indeed excludes releasable mechanisms.
The third question formulated by the proprietor essentially concerned whether, and if so, under which conditions, a prior-art document can be used as evidence for the understanding of the person skilled in the art in a certain technical field. This question could be answered by the board itself without doubt and thus without needing a referral.
When commenting T 1473/19, I noted that wanting to always interpret the claims in the light of the description is the usual way to deal with claims at the German Federal Court (BGH).
It was therefore debatable whether this approach should be taken over by the EPO, even with the proviso expressed in T 1473/19 that the primacy of the claims limits the extent to which the meaning of a certain claim feature may be affected by the description and the drawings.
The present decision does not bring a change of opinion in this matter, and the situation should actually be clarified by the EBA.
When a claim specifies that two pieces of a device are “permanently attached’’ it clearly and unambiguously means for the reader willing to understand, and not willing to misunderstand the claim, that by essence they are not to be released during a normal use of the device. That in real life a physical connection can always be detached if an appropriate external force is applied is in the present context beside the point.
I would like to draw the attention to the board to T 1431/06 which dealt with tube couplings. In claim 1 it was specified that a specific cap “cannot be unscrewed”.
The description of the patent as granted did not support interpreting the expression “cannot be unscrewed“ in an absolute sense of “cannot ever be unscrewed under any circumstances“.
Such an absolute interpretation was furthermore contrary to the common general knowledge of the person skilled in the art, as it is generally known that any material structure will eventually yield to the targeted application of sufficient force.
In T 1431/06, the board held the skilled person directly and unambiguously derived from the description of the patent as granted that, in claim 1, the term “cannot” is to be understood in the context of the normal use of the tube coupling, in which the cap cannot be unscrewed.
It can be agreed with the present board that patent claims must be interpreted through the eyes of the person skilled in the art. This does indeed includes taking account of the skilled person’s common general knowledge. But common general knowledge cannot be derived from patent documents.
However, taking the description as pretext to give an interpretation in flagrant contradiction to what is directly and unambiguously claimed and originally disclosed, i.e. both alternatives, or in other words, claiming that permanently is only relative is going a trifle too far.
The present decision does thus not appear to be correct.
Questions for a referral
The questions for the referral were much too directed to the actual case and it was easy for the board to dismiss the request for referral.
The fundamental question of law which should be decided by the EBA is whether recourse to the description under Art 69(1) and Art 1 of the Protocol has to be systematic or not, or only when dealing with Art 123(3) or in case of lack of clarity of the claims.
In defending its position against the referral, the board referred to T 1473/19. In this respect it can be said that the board was at the same time judge and party.