Abstract 2310: Peak Cardiac Power, Measured Non-Invasively, Is A Powerful Predictor Of Mortality In Chronic Heart Failure
OBJECTIVES: Invasive determination of hemodynamically derived variables (cardiac output response (CO), left ventricular stroke work index (LVSWI), cardiac power) have been described to be better prognostic indicators than peak VO2. Using non-invasive measurements of CO during exercise, we compared the prognostic value of peak CO, LVSWI and cardiac power to peak VO2 in heart failure (HF) patients referred for transplant (tx).
METHOD AND RESULTS: 142 HF patients(109 men;age 53±13 yrs) underwent bicycle exercise with non-invasive estimation of CO using an inert gas rebreathing method (Innocor, Copenhagen, Denmark). Ejection fraction averaged 23±10%. In 120 patients, an accurate measure of peak CO was achieved. Peak cardiac power was derived from the product of the peak mean BP and CO divided by 451. LVSWI was derived using an assumed peak pulmonary wedge of 30 mm Hg. Endpoints included death, urgent tx or LVAD. Follow-up averaged 308±191 days. Peak VO2 was 12.6±4.6 ml/kg/min, peak CO was 1.71±0.89 watts with a median of 1.5 watts. Univariate and multivariate analysis were performed. The variables analyzed included peak VO2, peak CO, % predicted peak CO, LVSWI and peak cardiac power. 1 year event free survival for the entire cohort was 83% with 1 death, 4 LVADs and 14 urgent txs. Peak VO2, peak CO, peak cardiac power and LVSWI were predictive of outcome on univariate analysis. On multivariate analysis, only LVSWI and cardiac power were predictive with cardiac power being the most powerful predictor (P<0.001).
CONCLUSION: Peak cardiac power, measured non-invasively, is an independent predictor of mortality that can enhance the prognostic power of peak VO2 in the evaluation of HF patients.