TABLE 2: Prognostic value of Maximal Exercise Tests in patients with ChC in the included studies (n=8).
| STUDY | POPULATION | EXERCISE TEST | RESULTS |
|---|---|---|---|
| De Paola et al. (1995) 43 | 69 patients with ChC (dilated and preserved LVEF), 46±12 years; 54% male; NYHA I-III, LVEF 46.6±18.6%. Follow-up period: 24±15 months. Endpoint: sudden death | Maximal Exercise Test (Bruce protocol, treadmill) | The number of patients with ventricular tachycardia at baseline was significantly higher in the sudden cardiac death group when compared to survivors (p<0.05). |
| Silva et al. (2017) 41 | 45 patients with dilated ChC, 50.24±10.79 years; 100% male. Endpoint: death | CPET (cycle ergometer) | The VO2peak AT is an independent predictor of death (AUC=0.706). When both Rassi score and AT were defined as independent variables. VO2peak AT increases the accuracy of the Rassi score for mortality prediction by 5%. |
| Souza et al. (2015) 42 | 21 patients with dilated ChC, 54.5±11.9 years, 38.1% male, NYHA III-IV, LVEF 29.2± 6.0%. Follow-up period: 24 months. Endpoint: cardiac death | CPET (ramp protocol, treadmill) | Differences between non-survivors ChC compared to survivors included lower peak HR (p=0.026), peak SBP (p=0.038), VO2peak (p=0.043), VO2peak AT (p=0.016), circulatory power (p=0.006) and ventilatory power (p=0.008). In the logistic regression, only circulatory power was independently associated with survival (OR 17.3 [95% CI: 1.39 to 217.0]). The circulatory power showed good accuracy in identify mortality (cut-off point ≤ 1280). |
| Ritt et al. (2013) 13 | 55 patients with dilated ChC, 52±9 years, 69% male, NYHA II-IV, LVEF 27.6±6.6%. Follow-up period: 32±19 months. Endpoint: cardiac death | CPET (ramp protocol, treadmill) | The VO2peak (p=0.03) and VE/VCO2 slope (p=0.01) differed significantly between survivors and non-survivors. The VO2peak was correlated with MLwHRQ (r= -0.301; p=0.02) and showed good accuracy in identifying mortality (cut-off ≤18 mL/kg/min). The VE/VCO2 slope showed good accuracy in identifying mortality (cut-off >32.5. After adjusting for age, LVEF, and Chagas score, VE/VCO2 slope remained an independent predictor of mortality (adjusted HR: 2.80, 95% CI: 1.30 to 5.80, and p=0.001 for those with VE/VCO2 slope ≥32.5). |
| Pedrosa et al. (2011) 44 | 130 patients with ChC (dilated and with preserved LVEF), 50.7±10.3 years, 40.8% male. Follow-up period: 9.9 years (range, 132 days to 17 years). Endpoint: cardiovascular death | CPET (Bruce protocol) | The prevalence of EIVA was 43.1%. Sex, age, and cardiothoracic index were not associated with EIVA. LVEF showed a statistically significant association with EIVA (p=0.01). The presence of EIVA alone was not a predictor of mortality but predicted mortality in Cox analysis, only when associated with age and cardiothoracic index >0.5 (hazard ratio=4.3 [95% CI: 1.6 to 11.4]; p=0.004). |
| Costa et al. (2018) 40 | 49 patients with dilated ChC, 50±7 years; 57% male; NYHA I-III, LVEF: 36.0 [31.0-41.0]%. Follow-up period: 39±14 months. Endpoint: cardiac death | Maximal Exercise Testing (Bruce protocol, treadmill) | Survivors had higher VO2peak (p=0.048) than non-survivors. In the final model, VO2peak (hazard ratio 1.2, 95% CI: 1.0 to 1.3; p=0.009) remained an independent predictor of cardiac death in ChC. The optimal cut-off point for VO2peak in predicting death was 25 mL/kg/min. However, the established cutoff point failed to demonstrate a difference between the groups with VO2peak below and above 25 mL/kg/min. |
| Mady et al. (1994) 12 | 104 patients with dilated ChC, 40.3±9.0 years; 100% male; NYHA II-IV, LVEF: 37.4±11.1%. Follow-up period: 41±12 months. Endpoint: cardiac death | CPET (Naughton protocol, treadmill) | The survivor group showed higher LVEF (=0.001), higher VO2peak (p=0.001), and better NYHA functional class (p=0.001) than that of those in the non-survivor group. In the multivariate model, VO2peak (p=0.001) and LVEF (p=0.008) remained independent predictors of cardiac death. Survival was significantly better in patients with VO2peak >20 mL/kg/min. |
| Costa et al. (2019) 39 | 75 patients with ChC (dilated and with preserved LVEF), 48.4±8.0 years; 61% male; NYHA I-III, LVEF: 41.0 [35.0-53.5]%. Follow-up period: 41±12 months. Endpoint: death, heart transplantation, or ischemic event | Maximal Exercise Test (Bruce protocol, treadmill) | Patients with adverse events had lower LVEF (p=0.002), higher LVDD (p=0.019) and worse mental component of HRQoL (p=0.043) compared to those in patients without adverse events. No differences were observed in age, sex, NYHA functional class, VO2peak, %HR achieved during exercise test, and HR recovery after exercise testing between groups. In the univariate analysis, VO2peak, %HR achieved during exercise test, and HR recovery after exercise testing were not associated with adverse events. |
Data presented as mean±standard deviation; mean [95% CI] or percentage. Abbreviations: ChC: Chagas cardiomyopathy; NYHA: New York Heart Association; LVEF: left ventricular ejection fraction; CPET: Cardiopulmonary Exercise Testing; VO2peak: peak oxygen uptake; EIVA: exercise-induced ventricular arrhythmias; AT: anaerobic threshold; AUC: area under the ROC curve; ROC: receiver operating curve; MLwHFQ: Minnesota Living with Heart Failure Questionnaire; HRQoL: health-related quality of life; LVDD: left ventricular end-diastolic diameter; E/e´ ratio: ratio of the early diastolic transmitral flow velocity to early diastolic mitral annular velocity; VE/VCO2 slope: minute ventilation/carbon dioxide production slope; 6MWT: six-minute walk test.