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 <40mmHg, iAVA ≤0.6 cm2/m2) with preserved LVEF (LGSAS) remains controversial because gradients may be similar after aortic valve replacement (AVR). We compared outcomes of LGSAS with AVR or medical therapy.
Methods and Results—Comprehensive echocardiographic measurements including hemodynamic calculations were completed in 260 prospectively identified patients with symptomatic LGSAS. Patients were followed for mortality over 28±24 months. AVR was performed in 123 patients (47%). In comparison to AVR patients, medical patients had a higher prevalence of diabetes (25% vs 41%, p=0.009), lower stroke volume index (36.4±8.4 vs 34.4±8.7 ml/m2, p=0.02), higher pulmonary artery pressure (38±11 vs 48±21 mmHg, p=0.001), higher creatinine level (1.1±0.4 vs 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 AVR and 73 (70%) in the medical group. AVR (HR=0.54 [95%CI 0.32-0.94], p<0.001) was independently associated with outcome and remained a strong predictor of survival after adjusting 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(SVi>35ml/m2) (p=0.22).
Conclusions—AVR is associated with better survival than medical therapy in patients with symptomatic low gradient severe AS and preserved LVEF.
- Received January 6, 2013.
- Revision received May 5, 2013.
- Accepted May 31, 2013.