The impact of aortic valve replacement on survival in patients with normal flow low gradient severe aortic stenosis: a propensity-matched comparison

AIMS: To assess the survival benefit of aortic valve replacement (AVR) in patients with normal flow low gradient severe aortic stenosis (AS). METHODS AND RESULTS: A retrospective study of prospectively collected data of 276 patients (mean age 75 ± 15 years, 51% male) with normal transaortic flow [flow rate (FR) ≥200 mL/s or stroke volume index (SVi) ≥35 mL/m2] and severe AS (aortic valve area <1.0 cm2). The outcome measure was all-cause mortality. Of the 276 patients, 151 (55%) were medically treated, while 125 (45%) underwent an AVR. Over a mean follow-up of 3.2 ± 1.8 years (range 0-6.9 years), a total of 96 (34.8%) deaths occurred: 17 (13.6%) in AVR group vs. 79 (52.3%) in those medically treated, when transaortic flow was defined by FR (P < 0.001). When transaortic flow was defined by SVi, a total of 79 (31.3%) deaths occurred: 18 (15.1%) in AVR group vs. 61 (45.9%) in medically treated (P < 0.001). In a propensity-matched multivariable Cox regression analysis adjusting for age, gender, body surface area, smoking, hypertension, diabetes mellitus, atrial fibrillation, peripheral vascular disease, chronic kidney disease, left ventricular ejection fraction, left ventricular mass, and mean aortic gradient, not having AVR was associated with a 6.3-fold higher hazard ratio (HR) of all-cause mortality [HR 6.28, 95% confidence interval (CI) 3.34-13.16; P < 0.001] when flow was defined by FR. In the SVi-guided model, it was 3.83-fold (HR 3.83, 95% CI 2.30-6.37; P < 0.001). CONCLUSION: In patients with normal flow low gradient severe AS, AVR was associated with a significantly improved survival compared with those who received standard medical treatment.