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

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.

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/m². The primary endpoint was defined as a combination of all-cause mortality and readmission with heart failure at 1 year.

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 cm²/m², 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.

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