Revista argentina de cardiología
versión On-line ISSN 1850-3748
FERNANDEZ, Alberto A. et al. Pronostic Value of Cardiac Power Determination in Patients with Chronic Heart Failure. Rev. argent. cardiol. [online]. 2005, vol.73, n.4, pp. 271-276. ISSN 1850-3748.
Work Objective To evaluate the predictive value of a new variable obtained through the cardiopulmonary exercise test, the maximum cardiac power (CPmx) during peak exercise. Research Design and Methods A group of heart failure patients were prospectively evaluated through the assessment of VO2 mx, CPmx (oxygen pulse × mean arterial tension) and cardiac reserve (CR) (CPmx - CPbasal). The values were compared according to the presence of events (heart failure, hospitalization or death). The incremental value through ROC curves and the association of their cut-points with events (log-rank test and Cox regression) were evaluated. Combined end point: admission for worsening HF and/or death. Results Sample of 157 patients, 83.4% men, aged 59±10 years, functional class III/IV: 22.3%. Severe LV systolic dysfunction 56.7%, events 22.9%, average follow up: 9 months. Patients with events showed lower values of VO2 mx (11.8 vs. 14.9 ml/kg/min, p< 0.001), CPmx (831 vs. 1079 watts, p = 0.003) and CR (465 vs. 676 watts, p = 0.002); ROC areas: (VO2 mx: 0.73; CPmx 0.68; CR 0.68, p = 0.34 between areas). Risk of events: for VO2 mx< 14 ml/kg/min HR 3.93 (95% CI 1.89-8.20) p< 0.001; CPmx< 780 HR 2.78 (CI 1.42-5.43), p = 0.003 and CR< 350 HR 2.75 (95% CI 1.42-5.35) p = 0.003. The incidence of events was of 8.5% in patients with normal VO2 and CP, 30.3% with only one altered index: HR 3.1 (95% CI 1.16-8.25) p = 0.024, and 45.2% with both altered indexes HR 5 (95% CI 1.81-13.75) p = 0.002. Conclusions CPmx is another variable to determine in the cardiopulmonary exercise test which could give incremental predictive value, added to other classical parameters.
Palabras clave : Congestive heart failure; Exercise test; Prognosis; Cardiac reserve.