Conclusion and Glimpse into the Future
ECS is currently required in approximately 1 % of patients undergoing TAVI and may be more frequent among those undergoing TA TAVI procedures. The Medtronic/CoreValve experience, which already excludes prosthesis embolization and annular rupture, suggests that the risk for ECS can be reduced to 0.1 % of TAVI patients.11 Currently, leading causes for ECS during TAVI are aortic injury, prosthesis embolization, and myocardial perforation, as well as annular rupture. Even in centers with an on-site cardiac surgery department and thus short reaction times in such bail-out situations, postoperative mortality of ECS is high (45–67 %), owing to the comorbid and fragile health status of inoperable or high-risk patient cohort currently selected for TAVI instead of open surgery. Therefore, minimizing ECS risk is the best way to improve outcomes.
It may be anticipated from the historical development of percutaneous coronary intervention that the need for ECS during TAVI may similarly decrease in the near future. Technical improvements in valve design such as the development of retrievable, repositionable TAVI devices may prevent prosthesis embolization and thus the need for ECS. Development of dedicated, pre-shaped stiff TAVI guidewires may reduce the risk for ventricular perforation. Better pre-procedural planning by routine use of contrast-enhanced computed tomography allows for better positioning, thus avoiding coronary obstruction and minimizing the risk for oversizing-induced annular rupture as well as paravalvular regurgitation by better prosthesis size selection. Paravalvular leak is further addressed by technical developments in valve design. The increasing tendency to avoid balloon valvuloplasty before valve implantation may reduce annular rupture. Similarly, miniaturization and improved flexibility of the delivery systems may help to reduce ECS for complications such as aortic perforation or dissection. Increasing operator experience and growing confidence in the procedure will further reduce the risk for ECS.
The 2012 valvular heart disease guidelines of the European Society of Cardiology mandate that TAVI should only be performed in hospitals with both cardiology and cardiac surgery department on-site. The requirement of an on-site cardiac surgery department as a prerequisite for TAVI has been approved with the highest level of recommendation (class 1); however, based on expert consensus only (level of evidence C). Scientific data to support this recommendation do not exist. Since 2012, TAVI has rapidly evolved and has made substantial technical (e.g., 14 F Sapien 3 prosthesis) as well as procedural (i.e., growing operator’s experience and confidence) progress to become a routine procedure, which is highly beneficial for patients at high risk for open surgery. In 2013, >10,000 TAVI procedures were performed in Germany, which was more than the number of isolated AVR. The risk for severe complications necessitating ECS during TAVI is low and will further decrease. If required, outcomes of ECS are bleak, mostly due to the risk profile of the patients currently considered for TAVI. Therefore ECS does thus not really serve as a valid safety net. Avoidance of complications by experienced operators appears to be more appropriate to improve outcomes of TAVI.