Low stroke volume index is an independent predictor of mortality among patients with low gradient severe aortic stenosis and preserved left ventricle function

Background: The aim of the current study was to evaluate whether assessment of stroke volume index (SVI) can be used to improve risk stratification among patients with low-gradient severe aortic stenosis and preserved ejection fraction. Methods: Study population included patients who underwent baseline echocardiography and were followed-up at the Medical Center (years 2004-2011). We identified 430 patients (mean age 77±11 years; 42% males) with aortic valve area ≤1.00 cm2, mean gradient<40 mmHg, a normal ejection fraction (EF≥50%) and no other significant valvular disease. Multivariate Cox proportional hazards regression modeling was used to evaluate the effect of SVI on the risk of death among the study population. Forward Stepwise regression with adjustment for age, gender, ischemic heart disease and time dependent surgical intervention was used to find the echocardiographic predictors of mortatliy in the study population. Results: Mean SVI among study patients was 39±7 mL (range 20-59 mL). Multivariate analysis showed that SVI was the most powerful echocardiographic parameter associated with long-term outcome: each 5 ml/m2 reduction in SVI was associated with a significant 18% (p=0.026) increase in adjusted mortality risk. Lower tertile of SVI (<36ml/m2) was shown to be associated with a significant 62% (p=0.012) increased risk of death during follow-up. Consistently, Kaplan-Meier analysis showed that the cumulative probability of survival during 5 years of follow-up was significantly lower among patients in the lower SVI tertile (Figure). ![Figure][1] Kaplan Meier Survival Curve Conclusion: Our findings suggest that reduced SVI is an independent predictor of long-term mortality among patients with low gradient severe aortic stenosis and preserved ejection fraction. [1]: pending:yes