Flow, Reflected by Stroke Volume Index, Is a Risk Marker in High-Gradient Aortic Stenosis Patients Undergoing Transcatheter Aortic Valve Replacement.

Background: Tools are needed to identify patients at increased risk after transcatheter aortic valve replacement (TAVR). Indexed stroke volume (SVi) is an echocardiographic measurement that is used for low-gradient aortic stenosis. We studied whether low SVi is a high-risk marker in patients with high-gradient aortic stenosis (HG-AS) and assessed the relationship between SVi and left ventricle (LV) systolic function in contributing to this risk.

Methods: A total of 816 consecutive patients who underwent TAVR were screened, and only patients with HG-AS were included. Low flow (LF) was defined as SVi ≤ 35 mL/m. The primary endpoint was defined as a combination of all-cause mortality and readmission with heart failure at 1 year.

Results: Of the 476 patients with HG-AS, 215 (45%) had LF. They had higher N-terminal pro b-type natriuretic peptide (NTproBNP) (2565 [1037-5492] vs 1730 [818-3575], P = 0.006) and smaller indexed valve area (0.30 ± 0.10 vs 0.37 ± 0.10 cm/m, P < 0.001) when compared with normal flow patients. The primary endpoint was higher in LF patients (hazard ratio, 1.49; 95% confidence interval, 1.01-2.21; P = 0.045). There were no statistical differences in the individual components of death (13.0% vs 8.9%, P = 0.16) or heart failure (14.9% vs 10.1%, P = 0.12). When stratified according to LV function, low SVi was associated with future adverse events in patients with reduced function (hazard ratio, 3.37; 95% confidence interval, 1.26-8.98; P = 0.015) with comparable clinical outcomes in those with preserved function. LF was an independent predictor of adverse events in the reduced LV function subgroup.

Conclusions: SVi can further characterize patients with HG-AS and may help to identify those who are at increased risk after TAVR.