It is available, in many locations, but only for a very select patient population meeting a long list of inclusion/exclusion criteria. The short answer is otherwise inoperable (by standard AVR) but it's not nearly that simple. There are Consensus Documents ("industry" approved recommendations for how to integrate into practice) for TAVR now available online that have basically everything you could ever want to know about TAVR, including the selection criteria:
http://content.onlinejacc.org/cgi/reprint/59/13/1200.pdf.
Increasing use of TAVR (expanding the patient group) in the US seems very likely as the technology evolves, as many expert surgeons are saying, but obviously there are no guarantees on timing or degrees of success. Often lost in the hope for the future of TAVR is the fact that standard AVR in low risk patients is already extremely safe, and it may be quite some time before TAVR ever begins to approach that and offer true clinical benefit.
I read an earlier version of the Consensus Documents a few months ago, prior to final publication, that I think had even more information, and for those with interest, it is pretty fascinating to learn more about the technology. One example, some procedures have been done without general anesthesia! :eek2: Potential complications have gotten a lot of attention, particularly stroke, but there are actually pros and cons depending on the complication. For instance, the risk of developing A-Fib has shown to be lower, while on the other hand, the risk of developing heart block requiring pacemaker has shown to be higher (as much as 40% odds with the Medtronic valve - wow!).
Anyway, back to the future of the TAVR, just to save everyone time reading through, here's part of what these guidelines have to say about expanding the patient groups in the future:
"Valve-in-Valve:
Although repeat operation can be considered, an attractive option is to use a TAVR procedure in which the device is deployed within the previously placed bioprosthesis (209,249–254). In multiple small series, transcatheter aortic valve-in-valve implantation appears to be a safe option for the management of bioprosthetic valve failure in patients at high risk for reoperative conventional AVR. In this setting, coronary anatomy should be carefully defined in order to minimize the possibility of coronary obstruction by the transcatheter prosthesis (209,220,250,255). In addition, valve-in-valve procedures require a large enough bioprosthetic valve inserted at the index operation to prevent patient prosthetic mismatch with the TAVR valve.
Bicuspid Valve:
The asymmetric valvular anatomy often seen with a bicuspid aortic valve theoretically predisposes to a noncircular expansion of the TAVR device, thereby creating an increased risk of paravalvular regurgitation (256). Because of this concern, the presence of a bicuspid aortic valve is considered a relative contraindication to TAVR. Since bicuspid aortic valve patients have generally been excluded from major TAVR trials, there is little clinical experience in this area. Several centers, however, have achieved reasonable success in selected bicuspid aortic valve patients with AS.
Lower Risk Populations:
Data from the STS Registry indicate that approximately 10% of patients undergoing AVR have an STS score 8 and therefore would be potential candidates for TAVR using current selection criteria. There has been interest in expanding the potential group of candidates for TAVR to include patients with an STS score 4. This would broaden to 25% the number of patients who might be treated with TAVR rather than AVR. There has been concern about the potential for “selection creep,” with more lower-risk patients treated with TAVR. This should be avoided until more evidence-based data become available on the outcome of TAVR versus AVR in these patients. The planned and ongoing trials evaluating both the Sapien and the CoreValve in lower-risk populations will be of central importance in identifying subsequent utilization of this technology in expanded patient groups."
