Impact of flow, gradient, and left ventricular function on outcomes after transcatheter aortic valve replacement

Objectives: To assess the impact of low flow with and without preserved left ventricular ejection fraction (LVEF) on outcomes after transcatheter aortic valve replacement (TAVR). Background: Prior studies have shown that patients with low flow, AVG, and LVEF have worse outcomes after TAVR. It is unclear whether low AVG and LVEF remain prognostic after adjusting for flow, and how the outcomes of patients with low flow with and without preserved LVEF compare after TAVR. The goal of this study was to provide insight into these open questions. Methods: Data from 340 TAVR patients at Brigham and Women's Hospital from 2011 through 2015 were analyzed. Low flow was defined as stroke volume index (SVI) ≤35 mL/m ² , low AVG as mean gradient < 40 mmHg, and reduced LVEF as < 50%. Results: Low flow was present in 96 (28.2%) patients, 48 (50.0%) of whom also had reduced LVEF. At 1 year, low flow was associated with increased mortality (21.9 vs 7.4%; P = 0.0002) and heart failure (HF) (20.8 vs 5.3%; P = 0.0113). Among patients with low flow, those with preserved LVEF had increased mortality (HR 5.17, 95% CI 2.73-9.80; P < 0.001) and HF (HR 7.69, 95% CI 3.86-15.31; P < 0.001). After adjusting for clinical factors, patients with low flow had increased mortality (HR 6.51, 95% CI 2.98-14.22; P < 0.001) and HF (HR 5.52, 95% CI 2.34-12.98; P < 0.001), while neither low AVG nor low LVEF were associated with increases in mortality or HF. Conclusions: In patients undergoing TAVR, low flow was an independent predictor of 1-year mortality and HF, and a stronger predictor than either low AVG or LVEF. Patients with low flow and preserved EF had increased mortality and HF at 1-year, while those with low flow and reduced EF had outcomes similar to patients with normal flow.