P793 Is gender a key determinant of exercise tolerance in moderate-to-severe aortic stenosis?

Abstract

Abstract Background Gender-related differences are known about pathophysiology and clinical outcome of aortic stenosis (AS). Nevertheless, the impact due to gender on effort intolerance as well as its mechanisms has not been defined. We sought to assess functional capacity in AS labelling gender differences. Methods Sixty patients [age 69(63-76)years; female 24(40%)] with at least moderate AS (rest Vmax >3 m/s) underwent to rest and exercise echocardiography with simultaneous cardiopulmonary exercise test (CPET) during maximal symptom-limited exercise. Differences on echocardiographic and CPET variables were assessed according to gender. Results Women showed lower effort tolerance [female vs male: workload 51(46.5-72.5) vs 92.5(74-118.5)watts, p<.0001; peakVO2 13.2(12-15.2) vs 17.7(14.2-22-7)mL/kg/min, p=.002; Predicted peakVO2 63.5(53.5-74) vs 76(61.5-101)%, p=.006; anaerobic threshold 11.4(9.8-13.2) vs 12.8(11.4-15-7)mL/kg/min, p=.01; VE/VCO2 29.5(26.1-30.2) vs 26.2(24.3-28.5), p=.008] characterized by lower chronotropic reserve [age-predicted heart rate (HR) reserve 69.5(58.6-78.9) vs 82.8(74.6-89.7)%, p=.003; HR reserve 40.5(33.6-51) vs 47.5(39-67.5), p=.02; HR recovery at 1 min 9(4-12) vs 14(8.5-20), p=.002)], lower cardiac output (CO) response [exercise CO 7.9(6.4-8.8) vs 8.6(7.9-9.9) L/min, p=.01; CO reserve 2.9(2.1-3.6) vs 4.3(3.2-5.4)L, p=.0008] and lower peripheral extraction [C(A-V)VO2 12(9.7-14.2) vs 15.4(13.8-16.6)mL/100mL, p=.0007]. At 12 months follow up, the incidence for AVR was 0.55(0.31-0.73) in women and 0.29(0.15-0.45) in men, while at 60 months it was respectively 0.69(0.44-0.85) and 0.59(0.11-0.35). Conclusions in women, moderate-to-severe AS generates a higher degree of functional limitation compared to men. A lower CO reserve, mainly determined by an impaired chronotropic response and lower C(A-V)O2, plays a central role. This unfavourable phenotype is associated with a less advanced LV remodelling pattern and an earlier incidence of AVR.