E. Murat Tuzcu

Impact of Aortic Valve Replacement on Outcome of Symptomatic Patients With Severe Aortic Stenosis With Low Gradient and Preserved Left Ventricular Ejection Fraction

Background— The optimal management of low-gradient “severe” aortic stenosis (mean gradient <40 mm Hg, indexed aortic valve area ⩽0.6 cm2/m2) with preserved left ventricular ejection fraction remains controversial because gradients may be similar after aortic valve replacement (AVR). We compared outcomes of low-gradient severe aortic stenosis with AVR or medical therapy. Methods and Results— Comprehensive echocardiographic measurements including hemodynamic calculations were completed in 260 prospectively identified patients with symptomatic low-gradient severe aortic stenosis. Patients were followed up for mortality over 28±24 months. AVR was performed in 123 patients (47%). Compared with AVR patients, medically treated patients had a higher prevalence of diabetes mellitus (25% versus 41%, P=0.009), lower stroke volume index (36.4±8.4 versus 34.4±8.7 mL/m2, P=0.02), higher pulmonary artery pressure (38±11 versus 48±21 mm Hg, P=0.001), and higher creatinine level (1.1±0.4 versus 1.22±0.5 mg/dL, P=0.02). These and other clinically relevant variables were entered into a propensity model that reflected likelihood of referral to AVR. This score and other variables were entered into a Cox model to explore the independent effect of AVR on outcome. During follow-up, 105 patients died (40%): 32 (30%) in the AVR group and 73 (70%) in the medical treatment group. AVR (hazard ratio, 0.54; 95% confidence interval, 0.32–0.94; P<0.001) was independently associated with outcome and remained a strong predictor of survival after adjustment for propensity score. Medical therapy was associated with 2-fold greater all-cause mortality than AVR. The protective effect of AVR was similar in 125 patients with normal flow (stroke volume index >35 mL/m2; P=0.22). Conclusions— AVR is associated with better survival than medical therapy in patients with symptomatic low-gradient severe AS and preserved left ventricular ejection fraction.