Mortality risk score for patients with Chagas cardiomyopathy and pacemaker

by Giselle de Lima Peixoto, Sérgio Freitas de Siqueira, Silvana Angelina D’Orio Nishioka, Anísio Alexandre Andrade Pedrosa, Ricardo Alkmim Teixeira, Roberto Costa, Martino Martinelli Filho

Background

Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker.

Methods

It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation.

Results

We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41–3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16–4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24–3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26–3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25–2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10–3.17; P = 0.020). The score identified patients with: low (0–20 points), intermediate (21–30 points) and high risk (>31points).The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696–0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920–0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692–0.785).

Conclusions

This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.