Diastolic Dysfunction Is Unmasked on Exercise in Patients With Asymptomatic, Severe Aortic Stenosis: An Invasive Hemodynamic Study

Abstract

Background: Optimal timing of aortic valve replacement remains difficult in patients with asymptomatic, severe aortic stenosis (AS). More accurate diagnostic methods are warranted for the detection of subtle ventricular impairment. We aimed to evaluate diastolic function in asymptomatic patients with severe AS. Methods: In this cross-sectional study, patients with asymptomatic, severe AS were evaluated with right heart catheterization at rest and during moderate exercise. The patients also underwent cardiopulmonary exercise testing to objectify functional capacity and confirm the absence of symptoms. Results: Between February 2019 and May 2021, we included 50 patients aged 70±12 years. The patients had severe AS with peak velocity 4.4±0.4 m/s, mean gradient 46±9 mm Hg, and an indexed valve area of 0.47±0.08 cm 2 at rest. All patients were asymptomatic and had normal left ventricular ejection fraction. Five patients had postcapillary pulmonary hypertension at rest. During exercise, 44 patients (88%) had an increase in the mean pulmonary artery pressure per increase in cardiac output of >3 mm Hg/L per minute, of whom 93% had a concomitant increase in the pulmonary artery wedge pressure per increase in cardiac output >2 mm Hg/L per minute, suggesting exercise-induced pulmonary hypertension due to left heart disease. Female gender and increasing age were associated with a higher increase in the pulmonary artery wedge pressure per increase in cardiac output ratio. The catheterization was well tolerated, and there were no adverse events. Conclusions: A large proportion of asymptomatic patients with severe, degenerative AS have exercise-induced postcapillary pulmonary hypertension.