Lower Transaortic Flow Rate Is Associated With Increased Mortality in Aortic Valve Stenosis

Abstract

Objectives: The association of transaortic flow rate (FR) with outcomes was tested in 1,661 patients with aortic valve stenosis (AS) in the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study.

Background: Low transaortic flow may complicate grading of AS. However, the association of lower transaortic FR with adverse outcomes has not been reported.

Methods: Transaortic FR was calculated from Doppler-derived stroke volume in milliliters divided by systolic ejection time in seconds and considered low if <200 ml/s. The association of transaortic FR with cardiovascular and all-cause mortality during 4.3-year follow-up was tested in time-varying Cox regression models run with aortic valve replacement as competing risk and reported as hazard ratio (HR) and 95% confidence interval (CI).

Results: Low transaortic FR was found in 21% of patients at baseline. Patients with low transaortic FR were older, had lower systemic arterial compliance and left ventricular mass, and included more women and patients with inconsistently graded severe AS and low stroke volume index (<35 ml/m²) (p < 0.01 for all). Low in-study transaortic FR was associated with higher rates of cardiovascular and all-cause mortality both in unadjusted analyses (HR: 2.56 [95% CI: 1.62 to 4.04]; and HR: 1.93 [95% CI: 1.35 to 2.75], respectively; p < 0.001 for both) and after adjustment for age, sex, randomized study treatment, hypertension, stroke volume index <35 ml/m², LV mass, and mean aortic gradient (HR: 2.79 [95% CI: 1.65 to 4.73]; and HR: 1.90 [95% CI: 1.27 to 2.84], respectively; p < 0.01 for both).

Conclusions: In patients with AS without known cardiovascular disease or diabetes, low transaortic FR was independently associated with higher rates of cardiovascular and all-cause mortality. (An Investigational Drug on Clinical Outcomes in Patients With Aortic Stenosis (Narrowing of the Major Blood Vessel of the Heart) (MK-0653A-043 AM4); NCT00092677).

Keywords: aortic valve stenosis; echocardiography; flow rate; outcomes.