Among 614 low-flow aortic stenosis (LFAS) patients undergoing transcatheter aortic valve replacement (TAVR), mitral regurgitation (MR) trajectories diverged sharply by phenotype. Classical low-flow low-gradient (cLFLG) patients showed the highest rates of MR worsening at 30 days — defined as a ≥1-grade increase on a 6-level ordinal scale — and cLFLG remained independently associated with MR worsening at both 30 days and one year in multivariable logistic models. Paradoxical LFLG (pLFLG, n=306) and low-flow high-gradient (LFHG, n=153) patients fared better. Critically, LFAS phenotype — not MR trajectory itself — emerged as the dominant predictor of adverse outcomes including all-cause death and heart failure hospitalization.
This finding matters because TAVR has rapidly expanded to higher-risk, complex patients where concurrent valve pathologies complicate prognosis. The study reframes post-TAVR MR not as an isolated echocardiographic finding but as a phenotype-dependent signal — cLFLG patients likely carry intrinsic myocardial dysfunction that persists regardless of successful aortic valve relief. Clinically, this supports stratified surveillance protocols rather than uniform post-TAVR echo schedules. However, important limitations temper enthusiasm: this is a retrospective, single-center analysis with incomplete follow-up (only 290 of 614 patients had one-year echo data), limiting power for outcome analyses. As a preprint posted on medRxiv and not yet peer-reviewed, these findings require independent validation before influencing clinical protocols. Nonetheless, the mechanistic framing — phenotype as destiny in LFAS — represents a meaningful conceptual step forward for structural heart disease management.