Sex-differences in aortic stenosis: Effect on functional capacity and prognosis

Too Little of a Good Thing: Strong Associations Between Cardiac Size and Fitness Among Women

BACKGROUND

Cardiorespiratory fitness (CRF) is associated with functional impairment and cardiac events, particularly heart failure (HF). However, the factors predisposing women to low CRF and HF remain unclear.

OBJECTIVES

This study sought to evaluate the association between CRF and measures of ventricular size and function and to examine the potential mechanism linking these factors.

METHODS

A total of 185 healthy women aged >30 years (51 ± 9 years) underwent assessment of CRF (peak volume of oxygen uptake [Vo2peak]) and biventricular volumes at rest and during exercise by using cardiac magnetic resonance (CMR). The relationships among Vo2peak, cardiac volumes, and echocardiographic measures of systolic and diastolic function were assessed using linear regression. The effect of cardiac size on cardiac reserve (change in cardiac function during exercise) was assessed by comparing quartiles of resting left ventricular end-diastolic volume (LVEDV).

RESULTS

Vo2peak was strongly associated with resting measures of LVEDV and right ventricular end-diastolic volume (R2 = 0.58-0.63; P < 0.0001), but weakly associated with measures of resting left ventricular (LV) systolic and diastolic function (R2 = 0.01-0.06; P < 0.05). Increasing LVEDV quartiles were positively associated with cardiac reserve, with the smallest quartile showing the smallest reduction in LV end-systolic volume (quartile [Q]1: -4 mL vs Q4: -12 mL), smallest augmentation in LV stroke volume (Q1: +11 mL vs Q4: +20 mL) and cardiac output (Q1: +6.6 L/min vs Q4: +10.3 L/min) during exercise (interaction P < 0.001 for all).

CONCLUSIONS

A small ventricle is strongly associated with low CRF because of the combined effect of a smaller resting stroke volume and an attenuated capacity to increase with exercise. The prognostic implications of low CRF in midlife highlight the need for further longitudinal studies to determine whether women with small ventricles are predisposed to functional impairment, exertional intolerance, and HF later in life.

Clinical significance and prognostic value of ST segment depression on ECG during exercise treadmill test in asymptomatic patients with moderate or severe aortic stenosis

Objectives. In patients with asymptomatic moderate or severe aortic stenosis (AS), exercise testing is used for evaluating the need for aortic valve intervention. Expert opinions about the clinical significance and prognostic value of ST segment depression on electrocardiography (ECG) during exercise testing in AS is conflicting and there are no large studies exploring this issue. We aimed to explore the association of ST segment depression >5 mm during exercise treadmill test (ETT) with all-cause mortality, aortic valve replacement (AVR) or cardiac-related hospitalization. Design. We performed a retrospective analysis of prospectively collected data of a total of 315 patients (mean age 65 ± 12 years, 67% men) with asymptomatic moderate (n = 209; 66%) or severe (n = 106; 34%) AS. All patients underwent clinical evaluation, echocardiography and ETT. Results. During a mean follow-up of 34.9 ± 34.6 months, 29 (9%) patients died and 235 (74%) underwent AVR. The prevalence of ST segment depression (>5 mm) was 13% (n = 41) in the total study population and was comparable in patients with revealed symptoms (17.6%, n = 16) versus without revealed symptoms (11.3%, n = 25; p = .132). ST segment depression on ETT was strongly associated with aortic valve area. In univariate Cox regression analysis, ST segment depression was not associated with cardiac related hospitalizations (HR 1.65; 95% CI 0.89-3.10, p = .113), all-cause mortality (HR 1.37; 95% CI 0.47-3.98, p = .564) or AVR (HR 1.30; 95% CI 0.89-1.91, p = .170). Conclusion. In patients with moderate or severe AS, ST segment depression during ETT is non-specific, carries no prognostic risk and should be used with caution in the clinical interpretation of exercise test.

Sex differences in aortic stenosis: from pathophysiology to treatment

Introduction: In aortic stenosis (AS), there are clear sex differences in clinical presentation, left ventricular (LV) response to pressure overload, and pathophysiology of valvular calcification. These differences may affect outcome following valve intervention.Area covered: This review aims to discuss sex differences in clinical presentation, pathophysiology of aortic valve calcification, LV remodeling in view of historic and recent echocardiographic and cardiac magnetic resonance imaging studies, and outcome after valve intervention. In addition, it will also provide some brief insights on the exercise physiology in women and men with AS.Expert commentary: Women at presentation are often older, have higher prevalence of hypertension and diastolic dysfunction, while men are younger, and more often have a bicuspid aortic valve and higher atherosclerotic disease burden. Men have more valve calcification than women for a given severity of AS and develop different patterns of LV remodeling and myocardial fibrosis. Although women tend to walk shorter on treadmill and achieve lower metabolic equivalents, they achieve similar peak heart rates and blood pressure, and the frequency of revealed symptoms during exercise test is comparable in both sexes. Men are more likely to undergo a surgical AVR with better outcome, while women have generally better outcome after TAVI.