Role of contractile reserve as a predictor of mortality in low-flow, low-gradient severe aortic stenosis following transcatheter aortic valve replacement

Objectives: The aim of this study was to determine the prognostic value of contractile reserve (CR) at baseline in patients with low-flow, low-gradient severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). Background: Patients with severe AS, left ventricular dysfunction, and low transaortic gradient are at high risk for mortality during surgical aortic valve replacement (SAVR). Furthermore, patients without CR have been shown to have perioperative mortality comparable to that of patients treated medically for severe AS. Methods: We retrospectively analyzed patients who underwent TAVR with a diagnosis of low-gradient severe AS (mean transvalvular aortic gradient < 40 mmHg, LVEF < 50%, and AVA ≤ 1.0 cm ² or AVAi ≤ 0.6 cm ² ) and who had a pre-TAVR dobutamine stress echocardiogram (DSE). Patients were stratified by the presence or absence of CR, defined as an increase in stroke volume ≥ 20% during DSE. Results: From 2008 to 2016, 61 patients with low-gradient severe AS underwent TAVR and had pre-TAVR DSE. CR was present in 31 patients (51%) and absent in 30 (49%). There was no significant difference between the two groups in baseline demographics, medical history, access site, or types of valves. All-cause mortality was similar in both groups at 30 days (13% with CR vs 10% without CR, P = 1.00) and 1 year (29% with CR vs 33% without CR, HR 1.20, 95% CI 0.49–2.96, P = 0.69). Conclusion: In patients with low-flow, low-gradient severe AS undergoing TAVR, the presence or absence of CR does not predict all-cause mortality at 30 days or 1 year.