Randomized Trial of Benznidazole for Chronic Chagas' Cardiomyopathy.

BACKGROUND: The role of trypanocidal therapy in patients with established Chagas' cardiomyopathy is unproven. METHODS: We conducted a prospective, multicenter, randomized study involving 2854 patients with Chagas' cardiomyopathy who received benznidazole or placebo for up to 80 days and were followed for a mean of 5.4 years. The primary outcome in the time-to-event analysis was the first event of any of the components of the composite outcome of death, resuscitated cardiac arrest, sustained ventricular tachycardia, insertion of a pacemaker or implantable cardioverter-defibrillator, cardiac transplantation, new heart failure, stroke, or other thromboembolic event. RESULTS: The primary outcome occurred in 394 patients (27.5%) in the benznidazole group and in 414 (29.1%) in the placebo group (hazard ratio, 0.93; 95% confidence interval [CI], 0.81 to 1.07; P=0.31). At baseline, a polymerase-chain-reaction (PCR) assay was performed on blood samples obtained from 1896 patients; 60.5% had positive results for Trypanosoma cruzi on PCR. The rates of conversion to negative PCR results (PCR conversion) were 66.2% in the benznidazole group and 33.5% in the placebo group at the end of treatment, 55.4% and 35.3%, respectively, at 2 years, and 46.7% and 33.1%, respectively, at 5 years or more (P<0.001 for all comparisons). The effect of treatment on PCR conversion varied according to geographic region: in Brazil, the odds ratio for PCR conversion was 3.03 (95% CI, 2.12 to 4.34) at 2 years and 1.87 (95% CI, 1.33 to 2.63) at 5 or more years; in Colombia and El Salvador, the odds ratio was 1.33 (95% CI, 0.90 to 1.98) at 2 years and 0.96 (95% CI, 0.63 to 1.45) at 5 or more years; and in Argentina and Bolivia, the odds ratio was 2.63 (95% CI, 1.89 to 3.66) at 2 years and 2.79 (95% CI, 1.99 to 3.92) at 5 or more years (P<0.001 for interaction). However, the rates of PCR conversion did not correspond to effects on clinical outcome (P=0.16 for interaction). CONCLUSIONS: Trypanocidal therapy with benznidazole in patients with established Chagas' cardiomyopathy significantly reduced serum parasite detection but did not significantly reduce cardiac clinical deterioration through 5 years of follow-up. (Funded by the Population Health Research Institute and others; ClinicalTrials.gov number, NCT00123916; Current Controlled Trials number, ISRCTN13967269.).

Effects of Trypanocidal Treatment on Echocardiographic Parameters in Chagas Cardiomyopathy and Prognostic Value of Wall Motion Score Index: A BENEFIT Trial Echocardiographic Substudy.

BACKGROUND: Serial echocardiographic studies in chronic Chagas cardiomyopathy are scarce. The aims of this study were to evaluate whether therapy with benznidazole modifies the progression of cardiac impairment and to identify baseline echocardiographic parameters related to prognosis. METHODS: A prospective substudy was conducted in 1,508 patients with chronic Chagas cardiomyopathy randomized to benznidazole or placebo, who underwent two-dimensional echocardiography at enrollment, 2 years, and final follow-up (5.4 years). Left ventricular (LV) ejection fraction, LV wall motion score index (WMSI), indexed left atrial volume, and chamber dimensions were collected and correlated to all-cause death and a composite hard outcome using univariate and multivariate analyses. RESULTS: At enrollment, most patients had normal chamber dimensions, and 70.5% had preserved LV ejection fractions. During follow-up, all chamber dimensions increased similarly in both treatment arms. LV ejection fraction was comparably reduced (55.7 ± 12.7% to 52.1 ± 14.6% vs 56.3 ± 12.7% to 52.8 ± 14.1%) and LV WMSI similarly increased (1.31 ± 0.41 to 1.49 ± 0.03 and 1.27 ± 0.38 to 1.51 ± 0.03) for the benznidazole and placebo groups, respectively (P > .05). A higher baseline LV WMSI was identified in subjects who died compared with those alive at final echocardiography (1.76 ± 0.517 vs 1.271 ± 0.393, P < .0001). There was a significant (P < .0001) graded increase in the risk for the composite outcome with worsening LV WMSI (hazard ratios, 2.27 [95% CI, 1.69-3.06] and 6.42 [95% CI, 4.94-8.33]) and also of death (hazard ratios, 2.45 [95% CI, 1.62-3.71] and 8.99 [95% CI, 6.3-12.82]) for 1 < LV WMSI < 1.5 and LV WMSI > 1.5, respectively. Both LV WMSI and indexed left atrial volume remained independent predictors in multivariate analysis. CONCLUSIONS: Trypanocidal treatment had no effect on echocardiographic progression of chronic Chagas cardiomyopathy over 5.4 years. Despite normal global LV systolic function, regional wall motion abnormalities and indexed left atrial volume identified patients at higher risk for hard adverse clinical outcomes.