Alec Vahanian (Paris) opened the session mentioning that a consensus paper between cardiologists and surgeons in the field of transcatheter aortic valve interventions (TAVI) has been published concomitantly in the European Heart Journal, the European Journal of Cardio-Thoracic Surgery, and Eurointervention, and introduced the lecturers of the session, who all had an important role in the writing of the document.
With two CE marked devices available, aortic valve implantation has become a clinical opportunity for high risk patients with calcified aortic stenosis. After more than 2500 implants worldwide with first generation devices, there is enough evidence at this time demonstrating the feasibility of the procedure, both via transfemoral and transapical approach. A valved stent can be implanted inside a stenotic aortic valve, obtaining a reasonably large effective valve orifice area, without compromising the coronary flow and with minimal aortic regurgitation in most occasions. But there is more to be demonstrated beyond feasibility.
Peter De Jaegere (Rotterdam, NL) reported that, in terms of safety, data available are quite scattered and stem mainly from either company reports or single institution meeting reports. Only few peer review articles are available, and most of them are out-of-date in terms of technology and patient selection. It is also impracticable at this time to analyse these data, due to significant differences in the methodology of data collection and in terms of definition of the adverse events. Moreover, as pointed out by Alec Vahanian (Paris) a head to head comparison between devices at this time should not be undertaken, until data collection is more adequate and consistent, and more data is accumulated on the procedure itself, rather than on the technology. The need for a registry of TAVI is mandatory to obtain reliable and independent data.
Success of implantation procedures
What is known is that valve implantation is successful in the vast majority of patients (above 90%). Stroke rate is between 5 and 10% with the transfemoral approach. The rate is however decreasing due to better patient screening and to technical progress and experience of the operators. Stroke rate seems to be lower in selected centers adopting the transapical approach. In particular, Thomas Walter (Leipzig) reported a 0% stroke risk in his series of 160 patients treated by transapical TAVI. On the other hand, a number of patients in his series required open heart conversion for a variety of reasons, reinforcing the case that TAVI are complex procedures, and operators have to be ready for the worst scenario in order to be prepared to deal with the complications. A high rate of complete AV block has been reported in the past with the Corevalve system.
P De Jaegere reported lower rates in the last patients and suggested the lower placement of the device as a possible cause for this complication. Procedural mortality is around 10 to 15% in most series, and it looks to be similar among devices and different approaches. Although procedural mortality is lower than that predicted by Euroscore, both Walter and Patrick Nataf (Paris) pointed out that Euroscore tends to overestimate the risk and that surgical series have shown similar data.
Mourat Tuzcu (Cleveland) gave a broad overview on imaging for TAVI, demonstrating the key role played by imaging both before and during the procedures. There is a growing role for CT scan, although conventional angiography remains the main imaging modality during the procedure. Echocardiography is very convenient for screening patients, but its role as a guidance tool during the implantation is questionable, while it remains fundamental as a monitoring tool and for decision-making after valve implantation.
The session was brought to a close by Nataf, who reported about patient selection. This topic is probably the most controversial at this time. It is clear that TAVI should be reserved to high risk patients, with predicted high mortality or morbidity after surgical aortic valve replacement. But calculating this risk today is not easy, and it requires a collaborative effort between the surgeon and the cardiologist. Nataf also pointed out that there are some patients who are too sick even for TAVI. Survival curves show that most late deaths occur in the first year after implant, while mortality decreases thereafter probably reflecting the latter issue.
Notes to editor
This congress report accompanies a presentation given at the ESC Congress 2008. Written by the author himself/herself, this report does not necessarily reflect the opinion of the European Society of Cardiology.