The review evaluated the association between paravalvular leaks and mortality, and other clinical outcomes in patients who undergo TAVR as well the assessment and treatment of the condition.
Noting that the association between paravalvular leaks and mortality is the Achilles’ heel of transcatheter aortic valve replacement, the authors cite the PARTNER (Placement of Aortic Transcatheter Valves) trial which showed that 66 percent of patients who underwent TAVR had mild or trace leaks, and 12 percent had moderate or severe leaks.
PARTNER also showed that all-cause mortality resulting from the leaks was similar to that of surgical aortic valve replacement at two years post-procedure (33.9 percent vs. 35.0 percent, respectively), but that paravalvular regurgitation was more frequent after TAVR and was associated with increased late mortality. The authors of this review noted that based on current literature, the direct causal relationship between paravalvular leaks and mortality remains to be determined.
Assessment of paravalvular leaks may be done using aortic root angiography or echocardiography. Angiography is readily available during TAVR procedures and provides essential information to intervene in the case of severe regurgitation, but it relies on subjective interpretation of one-dimensional images.
Three-dimensional echocardiography may be superior to two-dimensional echocardiography and Doppler measurements in quantifying aortic regurgitation, but its utility is limited by low-line density and low volume rates.
Treatments for significant paravalvular leaks that occur around transcatheter procedures include post-implantation balloon dilation of the valve to reduce leaks, repositioning of valves that are too low using a snaring maneuver and valve-in-valve procedures when other interventions do not improve the degree of paravalvular leak after TAVR. If these approaches fail, conversion to surgical valve replacement may be necessary.
The authors conclude that promising new transcatheter heart valve systems are on the horizon to reduce the occurrence of paravalvular leaks through improved annular sealing or controlled repositioning or removal of the valves. Techniques for debulking calcifications before valve implantation to improve valve expansion and sealing of the annulus also are under development.