BNP and longitudinal strain: early predictors of events and echocardiographic cardiac conversion progression in patients with Chagas disease in a non-endemic area

Abstract Background Chagas disease (CD) prevalence in Europe has risen due to migration. One-third of patients develop Chagas cardiomyopathy (ChCM), while most remain in the indeterminate phase. Some with indeterminate CD or isolated ECG abnormalities show elevated BNP or reduced myocardial strain, but their prognostic significance in non-endemic areas is unclear. Objectives To evaluate the natural course of CD in a non-endemic area and assess whether BNP and myocardial strain are associated with cardiovascular events or progression to the cardiac form. Methods Patients from endemic areas were screened for Trypanosoma cruzi at a tertiary hospital. Clinical history, ECG, BNP quantification, and baseline echocardiography, including speckle-tracking strain analysis, were performed. Clinical, ECG, and echocardiographic follow-up were conducted regularly. Patients were classified into four groups: controls, indeterminate CD, CD with ECG abnormalities but normal echocardiography, and CD with pathological echocardiography. The primary endpoint was a composite of advanced atrioventricular block, sinus dysfunction requiring pacemaker, sustained ventricular tachycardia, heart failure hospitalization, heart transplant, cardiovascular death, new LV dysfunction (LVEF 50%), or new segmental wall motion abnormalities/aneurysms. Secondary endpoints included echocardiographic progression and clinical events. Results A total of 118 patients and 71 controls were included. The mean age was 37±9 years, and 34% were male. Median follow-up was 121 months (IQR: 82.7). Cardiac involvement prevalence was 26% at baseline and 33% at follow-up. The primary endpoint occurred in 17/118 patients (14%): 5.7% (5/87) in the indeterminate group, 31% (5/16) in the ECG abnormalities group, and 46.7% (7/15) in the echocardiographic abnormalities group. No events occurred in controls (p0.01). Nine patients reached the secondary endpoint, with a conversion rate of 0.54% per year. Baseline echocardiography showed no significant differences in LV dimensions or LVEF between CD patients with normal echocardiograms and controls. However, longitudinal, radial, and circumferential strain worsened across severity groups. BNP was slightly elevated in indeterminate CD compared to controls. Excluding patients with abnormal baseline echocardiography, BNP (HR=1.03, p=0.001) and GLS (HR=0.66, p=0.012) predicted the combined event, adjusted for age, sex, and ECG abnormalities. Baseline ECG and BNP combination showed 98% specificity and 98% negative predictive value (NPV) for the primary endpoint. Conclusions In non-endemic patients with indeterminate CD or isolated ECG changes, elevated BNP and impaired GLS identify those at higher risk, aiding surveillance. A normal ECG and BNP had a 98% NPV, with implications for risk stratification and monitoring.