Gender-affirming hormone therapy and its impact on myocardial mass and cardiac function: a prospective magnetic resonance cohort study on transgender men and women.

Myocardial mass increased significantly in transgender men (AFAB) after 6 months of gender-affirming hormone therapy.

• Myocardial mass increased from mean (±SD) 48 (±8) g/m² at baseline to 54 (±7) g/m² at follow-up (P = .011).
• The study enrolled 20 individuals assigned female at birth (AFAB) undergoing GAHT.
• Measurements were taken before GAHT and at 6-month follow-up using 3-Tesla ECG-gated MRI.
• The study was conducted at the Medical University of Vienna from 2019 to 2022.

Myocardial mass showed a nonsignificant decrease in transgender women (AMAB) after 6 months of gender-affirming hormone therapy.

• Individuals assigned male at birth (AMAB) showed a nonsignificant decrease of 4 (±14) g/m² in myocardial mass.
• The study enrolled 15 individuals assigned male at birth (AMAB) undergoing GAHT.
• The change did not reach statistical significance.

NT-proBNP levels were significantly reduced in AFAB individuals at 6-month follow-up.

• Brain natriuretic peptide levels decreased from median (IQR) 41 (26–57) pg/mL at baseline to 19 (12–34) pg/mL at follow-up in AFAB individuals.
• The reduction was statistically significant.
• NT-proBNP is a marker related to cardiac stress and function.

No significant changes in left ventricular ejection fraction, stroke volume, cardiac output, or peak filling rate were observed in either AFAB or AMAB groups after 6 months of GAHT.

• LVEF, stroke volume, cardiac output, and peak filling rate were measured using 3-Tesla ECG-gated MRI.
• No significant changes were noted in both AFAB and AMAB groups at 6-month follow-up.
• This indicates that overall cardiac function was preserved despite changes in myocardial mass in AFAB.

Neither testosterone levels, estradiol levels, nor body mass index was related to myocardial mass at follow-up in either group.

• Testosterone levels were not correlated with myocardial mass at follow-up in AFAB (r = -0.127, P = .679) or AMAB (r = -0.127, P = .679).
• Estradiol levels were not correlated with myocardial mass at follow-up in AFAB (r = -0.154, P = .616) or AMAB (r = -0.154, P = .616).
• Body mass index was also not related to myocardial mass at follow-up.

The study used 3-Tesla ECG-gated MRI to measure myocardial mass and cardiac function parameters, and magnetic resonance spectroscopy to quantify myocardial lipid content.

• Cardiac parameters measured included myocardial mass, LVEF, stroke volume, cardiac output, and peak filling rate.
• Myocardial lipid content was quantified using magnetic resonance spectroscopy.
• Measurements were performed before GAHT initiation and at 6-month follow-up.
• This is described as a prospective cohort study registered at ClinicalTrials.gov (NCT06245681).