Prognostic influence of paravalvular leak following TAVI: is aortic regurgitation an active incremental risk factor or just a mere indicator?

Transcatheter aortic valve implantation (TAVI) has become the treatment of choice for inoperable patients with severe aortic stenosis and is a valuable therapeutic option for patients at high risk. Recent data suggest that TAVI can also be adopted in intermediate risk patients with competitive results when compared with surgery. For further expansion of indications, TAVI should, however, be demonstrated to be safe and effective in the longer term, and reduce the rate of complications. Paravalvular leak (PVL) after TAVI is a frequent problem and is considered the Achille’s heel of TAVI. A recent meta-analysis including 12 926 TAVI patients reported a pooled estimate incidence of moderate or severe PVL of 11.7%. Residual moderate/severe PVL has a relevant negative prognostic impact and has been associated with an increased risk of all-cause mortality. More recently, it has been suggested that mild PVR may also be a relevant predictor of mortality, but this association remains controversial. This report from Kodali et al. represents the largest published single study to evaluate the impact of PVL following TAVI with the Edwards Sapien valve (and one of the largest overall ever reported) on clinical and echocardiographic outcome. In this analysis, the impact of varying degrees of PVL on mortality as well as changes in ventricular function was evaluated in 2434 patients from the randomized cohorts and continued access registries of the PARTNER Trial. PVL was graded as none/trace in 52.9%, mild in 38.0%, and moderate/severe in 9.1%. Significant differences in baseline clinical and echocardiographic characteristics were observed among the groups, suggesting that patients with moderate/severe PVL were in slightly worse clinical condition. Overall, all patients demonstrated an improvement, with an increase in systolic function and a reduction in left ventricular (LV) mass index. For the first time, it has been reported that the magnitude of mass regression was significantly reduced in patients with residual moderate/severe PVL. The 30-day mortality was not different according to the severity of the PVL, but at 1 year all-cause mortality, cardiac-related mortality, and re-hospitalization rate were significantly increased with worsening PVL. The presence both of moderate/severe PVL [hazard ratio (HR) 2.18] and of mild PVL (HR 1.27) was independently associated with higher late mortality at multivariable analysis. As the authors stated, the main finding of this study is that, although the differences in the baseline clinical and echocardiographic profile ineithermild ormoderate/severePVL independently resulted in impaired clinical outcome and significantly higher 1-year mortality, patients with moderate/severe PVL demonstrated increases in LV end-diameter (LVED) and less reduction in LV mass index when compared with patients with less PVL. The finding that even mild degreesof regurgitation havea prognostic impact in aortic stenosis patients is in contrast to the traditional belief that aortic regurgitation is a well tolerated condition. Turina et al. reported in a cohort of 80 patients with isolated aortic regurgitation undergoing right and left heart catheterization that all patients suffering from moderate aortic regurgitation were still alive after 4 years. In this cohort, 10-year survival was as high as 79%, irrespective of symptom status. In the same line were the results from the extreme risk CoreValve trial, showing only severe but not mild or moderate PVL being associated with increased 1-year mortality. What is behind this dissimilarity? Is it patient characteristics? Measurement bias? Haemodynamics of TAVI? Valve properties? The issue remains open. Figures 1 and 2 show an example of PVL management (CoreValve snaring) and an algorithm of the different PVL treatment option, respectively. Patients’ characteristics may play a role. The French registry has demonstrated that patients with baseline mixed aortic stenosis and