A comprehensive international study revealed that myocardial fibrosis may be a predictor of mortality in patients with severe aortic stenosis undergoing aortic valve replacement.
In the study, published in JAMA Cardiology, investigators involved 822 patients across 13 international sites and found comparable extracellular volume fraction (ECV%) levels between male and female patients; however female patients had significantly lower levels of late gadolinium enhancement (LGE).
The primary outcome of the study was all-cause mortality post–aortic valve replacement (AVR), while cardiovascular mortality served as a secondary endpoint.
The investigators analyzed cardiovascular magnetic resonance (CMR) images using standardized protocols across all centers, employing T1-mapping and LGE to assess fibrosis. The robust methodology linked myocardial fibrosis to post-AVR outcomes, with all-cause mortality recorded at 11.3% among 670 patients without obstructive coronary artery disease (CAD) during a median follow-up of 3.7 years.
Higher ECV% and LGE were significantly associated with increased mortality. Female patients demonstrated an adjusted hazard ratio (HR) of 1.08 per 1% ECV% increase (95% confidence interval [CI] = 1.04–1.12, P < .001), whereas male patients had an HR of 1.01 (95% CI = 0.96–1.06, P = .66). For LGE presence, adjusted HRs were 2.49 (95% CI = 1.07–5.80, P = .03) among female patients and 1.82 (95% CI = 1.00–3.32, P = .04) among male patients.
Notably, female patients had lower LGE prevalence (29.8% vs 50.0%, P < .001) and infarct-related LGE (3.3% vs 7.6%, P = .03) compared with male patients. They also displayed lower left ventricular (LV) wall thickness and mass indices.
"In patients with severe [aortic stenosis] (AS) undergoing AVR, [female patients] have less wall thickening, hypertrophy, and replacement myocardial fibrosis than [male patients], but have similar ECV%. Myocardial fibrosis provides significant prognostic information in both [male] and [female patients] with AS undergoing AVR," said lead study author Soongu Kwak, MD, of the Department of Internal Medicine at the Seoul National University Hospital in South Korea, and colleagues.
The study’s large sample size and balanced sex representation enhance its generalizability. However, the investigators noted the need for further investigation into the mechanisms driving these sex differences. Subgroup analysis revealed consistent prognostic associations regardless of surgical or transcatheter AVR. Additionally, while this study focused on severe AS cases scheduled for AVR, further validation in patients with less severe AS is warranted.
Full disclosures are detailed in the study.
