Aortic regurgitation (AR) after transcatheter aortic valve replacement (TAVR) has been associated with significant adverse outcomes;1–4 therefore, its assessment is clinically important. The most common cause of AR post-TAVR is paravalvular leak (PVL), which occurs if the valve is undersized; annulus geometry is markedly elliptical or the prosthetic valve does not seat properly against the native valve tissue due to excessive calcium or malpositioning. The second Valve Academic Research Consortium-2 (VARC-2) gives recommendations for grading the severity of PVL5 but these are based on expert consensus and not empirically-derived data. Two papers attempt to address the difficult and clinically vexing problem of how to grade the severity of PVL after TAVR.6 ,7 Both studies compare transthoracic echocardiography (TTE) with cardiac MRI (CMR) for grading severity of PVL. Both pertain to balloon-expandable valves (Sapien, Sapien XT, Sapien 3, Edwards Lifesciences, Irvine, California, USA) using both transfemoral and transapical approaches. Both used a similar methodology for CMR quantitation of regurgitant fraction (RF) and regurgitant volume (RV) by phase contrast imaging.

Orwat et al6 compared TTE grading with quantitative flow measurement by CMR with calculation of RF for the assessment of AR. CMR was completed in 59 of 65 consecutive patients a median of 69 days post-TAVR, with both TTE and CMR being done on the same day. TTE grading of PVL as none, mild, moderate or severe was done subjectively by incorporating circumferential extent of the AR jet origin in a short-axis view, jet width in a long-axis …