Noninvasive Predictors of Mortality for Patients with Chagas’ Heart Disease: A Multivariate Stepwise Logistic Regression Study

Abstract

This prospective investigation was conducted in an attempt to identify noninvasive predictors of mortality for patients with Chagas’ heart disease through a multivariate stepwise logistic regression study. Fifty-six patients with a positive complement fixation test for Chagas’ disease were followed up at the Cardiomyopathy Clinic of our institution from April 1990 to April 1992. Patient age was 59 ± 17 years; 28 (50%) were male. Upon admission, 19 patients (33%) were in the New York Heart Association (NYHA) class III and 8 (14%) in the NYHA class IV. Systolic blood pressure was 125 ± 23 mm Hg, diastolic blood pressure 76 ± 11 mm Hg and resting heart rate 77 ± 11 beats/min. Forty patients (71%) were given digitalis and 39 (69%) angiotensin-converting enzyme inhibitors. Plasma Na⁺ was 140 ± 4 mEq/1, K⁺ was 4.34 ± 0.73 mEq/1 and creatinine level 1.34 ± 0.31 mg/l00 ml. Cardiomegaly was observed in the chest X-ray of 41 of 51 (79%) available patients. Atrial fibrillation was observed in the resting ECG of 24 of 54 (44%) available patients, premature ventricular contractions in 23 (41%), right bundle branch block in 26 (46%) and left anterior hemiblock in 26 (46%) patients. Echocardiography revealed a left ventricular ejection fraction of 0.45 ± 0.16, left ventricular systolic dimension of 51.23 ± 13.53 mm and left ventricular diastolic dimension of 62.94 ± 19 mm. Sixteen (28%) patients died during the 2-year study, 11 of them suddenly. By univariate analysis, left ventricular ejection fraction (p = 0.03), left ventricular diastolic dimension (p = 0.03), NYHA class IV (p = 0.0004) and digitalis use (p = 0.04) were found to be associated with mortality. In the multivariate model, however, only left ventricular ejection fraction was retained as an independent predictor of mortality. Actuarial survival was 75% for patients with left ventricular ejection fraction > 0.30, and 40% for patients with left ventricular ejection fraction < 0.30 (p = 0.03). We conclude that patients with Chagas’ heart disease having a left ventricular ejection fraction < 0.30 determined echocardio-graphically are at very high risk of dying.