Cardiovascular Adaptations During the Hormonal Transition of a Male-to-Female Transgender Athlete

Abstract

PURPOSE: Cardiovascular consequences of female sex hormone exposure on human male biology are currently unknown. This level of investigation is critical given potential adverse outcomes reported in rodent models. This case study aimed to comprehensively assess cardiovascular phenotypes before and during estrogen treatment for gender reassignment METHODS:This is the case of a biologically male, distance runner (28 yr) undergoing male-to-female gender reassignment. Two baseline assessments were made prior to initiation of hormone treatment. Testing following initiation of estrogen treatment took place at 4-8 week intervals depending on subject’s availability. Testing included resting echocardiography for assessment of biventricular function, dual energy x-ray absorptiometry (DXA), and central vascular blood pressures and stiffness assessments. Treadmill-based VO2 peak and running economy, as well as non-invasive cardiac output and a-vO2 difference at rest and at peak exercise were quantified at each visit RESULTS: Throughout the first 12 months of treatment, stroke volume decreased (136 to 80 ml/beat) with an initial reduction in peak heart rate (ranged 188-180 bpm). Consequently, peak cardiac output declined (28.4 L/min to 15.5 L/min) while a-vO2 difference increased (11.6 to 19.9 ml O2/100 ml blood). This resulted in only a minor decrease in absolute VO2 peak (3.3 to 3.1 L/min). Ejection fraction (calculated using modified Simpson’s method via echocardiogram) decreased (61% to 57%) along with left ventricular diastology (mitral valve E/e 6.0 to 4.1). Right Ventricular Fractional Area change was unaffected (53% to 53%), while measures of right heart diastology increased (tricuspid valve E/e 3.9 to 4.6). Both right ventricular (RV) and left ventricular (LV) strain initially improved with the addition of estrogen, before worsening over the course of hormone treatment (RV strain ranged from -36 to -31.5%; LV strain ranged from -23.5 to -19%) CONCLUSIONS: Therapeutic estrogen administration and testosterone blockade may adversely affect cardiopulmonary fitness via reduction in myocardial performance at peak exercise. This may be associated with a worsening of LV and RV strain at rest. More research is needed to examine the long-term effects of gender reassignment therapy on cardiovascular function