Outcome After Aortic Valve Replacement for Low-flow/low-gradient Aortic Stenosis Without Contractile Reserve on Dobutamine Stress Echocardiography

Objectives: This study investigated whether aortic valve replacement (AVR) is associated with improved survival in patients with severe low-flow/low-gradient aortic stenosis (LF/LGAS) without contractile reserve (CR) on dobutamine stress echocardiography (DSE).

Background: Patients with LF/LGAS without CR have a high mortality rate with conservative therapy. The benefit of AVR in this subset of patients remains controversial.

Methods: Eighty-one consecutive patients with symptomatic calcified LF/LGAS (valve area <or=1 cm(2), left ventricular ejection fraction <or=40%, mean pressure gradient [MPG] <or=40 mm Hg) without CR on DSE were enrolled. Absence of CR was defined as the absence of increase in stroke volume of >or=20% compared with the baseline value. Multivariable analysis and propensity scores were used to compare survival according to whether or not AVR was performed (n = 55).

Results: Five-year survival was higher in AVR patients compared with medically managed patients (54 +/- 7% vs. 13 +/- 7%, p = 0.001) despite a high operative mortality of 22% (n = 12). An AVR was independently associated with lower 5-year mortality (adjusted hazard ratio from 0.16 to 5.21 varying with time [95% confidence interval: 0.12-3.16 to 0.21-8.50], p = 0.00026). In 42 propensity-matched patients, 5-year survival was markedly improved by AVR (65 +/- 11% vs. 11 +/- 7%, p = 0.019). Associated bypass surgery (p = 0.007) and MPG <or=20 mm Hg (p = 0.035) were independently predictive of operative mortality. Late survival after AVR (excluding operative death) was 69 +/- 8% at 5 years.

Conclusions: In patients with LF/LGAS without CR on DSE, AVR is associated with better outcome compared with medical management. Surgery should not be withheld from this subset of patients solely on the basis of lack of CR on DSE.