Left Atrial Coupling Indexes as New Mortality Predictors in Chronic Chagas Disease

Abstract

Purpose

This study aimed to evaluate the all-cause mortality predictive value of left atrioventricular coupling indexes in patients with chronic Chagas disease (CD).

Methods

This single-center retrospective longitudinal study included 382 patients with chronic CD. The left atrioventricular coupling index (LACI) was defined as the ratio of left atrial (LA) over left ventricular (LV) end-diastolic volumes. LA volumetric/mechanical coupling index (LAVI/A’) was the ratio of maximum LA volume index over late diastolic mitral annulus velocity. The endpoint was a composite of all-cause mortality or heart transplant. The associations between LACI or LAVI/A’ and the endpoint independent from clinical, electrocardiographic, and 2D echocardiographic parameters (Model I) or from Model I adjusting variables plus LV and LA strain parameters (Model II) were tested by multivariate Cox-proportional-hazards regression.

Results

After a mean follow-up of 6.6 ± 2.7 years, 80 patients died and two underwent a heart transplant. LACI was associated with the endpoint in Models I (HR 1.03, 95% CI 1.01–1.05, p = 0.01) and II (HR 1.03, 95% CI 1.01–1.05, p = 0.0008). LAVI/A’ was also associated with the endpoint in Models I (HR 1.08, 95% CI 1.05–1.12, P < 0.0001) and II (HR 1.09, 95% CI 1.05–1.12, P < 0.0001). The area under the ROC curve was larger for LAVI/A’ than LACI (0.87 vs. 0.65, P < 0.0001). The optimal cutoff value for LAVI/A’ was 3.3 mL × s/cm⁻¹ per m² (sensitivity 81.7%, specificity 83.7%). Patients with LAVI/A’ ≥ 3.3 at baseline had a 19-fold higher risk for all-cause mortality.

Conclusion

New echocardiographic LA coupling indexes are promising predictors of dismal clinical outcomes in CD.