Risk of stroke in patients with Chagas cardiomyopathy is associated with depressed LV function but not with LV myocardial fibrosis or apical aneurysm: a study using cardiovascular magnetic resonance

Abstract

Abstract Background Chronic Chagas cardiomyopathy (CCC) is classically related to higher occurrence of thromboembolic events, especially stroke, particularly in patients with atrial fibrillation (AF). However, risk factors for stroke in patients with CCC but no atrial fibrillation have not been well established. Purpose We aimed to assess the relationship between left ventricular (LV) structure and function, as evaluated with cardiac magnetic resonance (CMR), with stroke in individuals with CCC. Methods We prospectively collected data from 141 patients with CCC who underwent CMR from October 2009 to December 2013 and who were thereafter followed for a median period of 6.8 years. The outcome was the occurrence of stroke during the follow-up period. The only exclusion criteria were history of previous stroke, AF or use of oral anticoagulant (OAC) at the time of CMR. CMR-derived LV parameters were: LV ejection fraction (LVEF), extension of LV myocardial fibrosis, assessed by late gadolinium enhancement, and presence of LV apical aneurysm. LVEF was classified as follows: (I) normal ≥55%; (II) mid-range <55% and ≥40%; and (III) reduced <40%. Age and gender were covariates in the adjusted Cox proportional hazard model. Results Of the initial 141 CCC participants, 25 subjects were excluded due to previous stroke (n=2), history of AF (n=11), or use of OAC (n=12). The remaining 116 individuals had a mean age of 56±14 years, 51% women. Normal, mid-range and reduced LVEF were found in 48 (41%), 43 (37%), and 25 (22%) patients, respectively. Myocardial fibrosis was detected in 79 of 111 (71%) subjects in whom the detection method was feasible. The extension of LV fibrosis was evaluated as a median of 4.6% [interquartile range: 0–10]. LV apical aneurysm was identified in 36 (31%) patients. During the follow-up (median 6.8 years), stroke was reported in 9 participants. In the univariate analysis, reduced LVEF was significantly associated with higher risk of stroke compared to normal LVEF (HR: 9.2, 95% CI: 1.8–48.4), while there was no significant difference between mid-range and normal LVEF (HR: 1.2, 95% CI: 0.2–8.2). The association of reduced LVEF and stroke remained significant in the multivariable model, adjusted for age and gender (HR: 12.6, 95% CI: 1.9–83.2). Kaplan-Meier curves are presented in figure 1 (logrank p-value <0.001). Neither the extension of LV myocardial fibrosis (HR: 1.0, 95% CI: 0.9–1.1) nor the presence of LV apical aneurysm (HR: 1.9, 95% CI: 0.5–7.2) was related to higher risk of stroke. Conclusion In patients with CCC, reduced LVEF assessed by CMR, but not LV fibrosis or presence of apical aneurysm, was a significant predictor of stroke. Funding Acknowledgement Type of funding source: None