Abstract 13539: Functional Evaluation in Aortic Stenosis: Determinant of Exercise Capacity

Abstract

Background: Aortic stenosis (AS) is clinically characterized by dyspnea and intolerance to exercise. Clinical interpretation of such symptoms is often difficult due to the advanced age of AS patients. We aimed at identifying cardiac determinants of exercise intolerance in AS (Aortic Vmax >3 m/s). Methods and results: We performed cardiopulmonary exercise test (CPET) simultaneously combined with exercise echocardiography in 43 patients with AS referred for functional assessment. Severe AS were evaluated because of symptoms not certainly related to valvular disease. Patients underwent a symptoms-limited maximal exercise, considering the 75% of predicted VO2 consumption as a marker of preserved functional capacity. Twenty-three patients had preserved functional capacity (group A), showing higher work, maximal VO2, O2 pulse and better VE/VCO2 and heart rate recovery. No differences were found in terms of rest systolic function and AS severity, while group A had higher peak heart rate (HR), higher peak cardiac power output (cardiac output x systolic pressure) and higher peak-rest transaortic mean gradient difference (ΔMG). At multivariate analysis, only ΔMG resulted independently associated with impaired functional capacity (p =0.048; CI 1.001-1.323). Conclusions: AS patients can present functional impairment which is related to cardiac response to exercise rather than to stenosis severity. These results suggest the role of inotropic and contractile reserve supporting the routinely evaluation of cardiac reserve as a determinant of symptoms development.