Clinical and Echocardiographic Characteristics of Flow-Based Classification Following Balloon-Expandable Transcatheter Heart Valve in PARTNER Trials

Abstract

BackgroundCurrent expected normal echocardiographic measures of transcatheter heart valve (THV) function were derived from pooled cohorts of the randomized trials; however, THV function by flow state before or following transcatheter aortic valve replacement (TAVR) has not been previously reported. ObjectivesThis study sought to assess the expected normal echocardiographic hemodynamics for the balloon-expandable THV grouped by stroke volume index (SVI). MethodsPatients with severe aortic stenosis enrolled in PARTNER (Placement of Aortic Transcatheter Valves) 1 (high/extreme surgical risk), PARTNER 2 (intermediate surgical risk), or PARTNER 3 (low surgical risk) trials with complete core laboratory echocardiography were included. Patients were grouped by low-flow (SVILOW <35 mL/m2) and normal-flow (SVINORMAL ≥35 mL/m2). Mean gradient, effective orifice area (EOA), and Doppler velocity index (DVI) were collected at baseline and at 30 days post-TAVR. Prosthesis-patient mismatch (PPM) was both calculated and predicted from normative data, using defined criteria. ResultsIn the entire population (N = 4,991), mean age was 81.8 years, 58% of patients were male, and 42% had low flow. Compared with patients with baseline SVINORMAL, those with SVILOW were more likely to be male; have more comorbidities; and lower left ventricular ejection fraction, mean gradient, and EOA. Post-TAVR, SVILOW increased to SVINORMAL in 17.3% and SVINORMAL decreased to SVILOW in 12.3% of patients. Using baseline SVI, follow-up EOA, mean gradient, and DVI for patients with SVILOW tended to be lower than for patients with SVINORMAL. Using the post-TAVR SVI, follow-up EOA, mean gradient, and DVI were significantly lower for patients with SVILOW than for those with SVINORMAL (P < 0.001 for all). The incidence of calculated, but not predicted, severe PPM was higher in patients with low flow than it was in patients with normal flow, suggesting pseudo-PPM in the presence of low flow. ConclusionsThis study demonstrates that flow affects THV hemodynamics and both baseline and follow-up SVI should be considered when predicting THV hemodynamics prior to TAVR, as well as assessing valve function following valve implantation.