The unsurpassed value of cardiopulmonary exercise testing in assessing the prognosis of heart failure

Abstract

Abstract Introduction Cardiopulmonary exercise testing (CPET) has become an important clinical tool to predict outcome in patients with chronic heart failure (CHF) and help to select candidates for heart transplantation (HTx) or left ventricular assist devices (LVAD). Purpose To evaluate CPET measurements in advanced CHF patients that are being considered for HTx or LVAD and its association to early mortality regardless of the performed procedure. Methods Maximum intensity CPET was performed on a treadmil and ramp protocol in 65 patients with patients with CHF and reduced ejection fraction, NYHA functional classes III and IV between 2012 and 2018. Measurements derived from CPET were the following: peak V'O2, VO2 at the anaerobic threshold (AT), percentage of the VO2 of the anaerobic threshold in relation to the peak, the VE/VCO2 slope, maximum heart rate (HR), respiratory quotient (R), oxygen kinetics, circulatory power (CP), the recovery HR in the first minute and the oxygen uptake efficiency slope (OUES) and the relation (VE/VCO2 slope)/VO2 peak. Results Seventy-four percent were male. Mean age of 67±12 years. Amost half (47%) had ischemic etiology. There were no complications related to CPET. Ten patients were transplanted, six had an intracorporeal LVAD implanted and the reminder (49 patients) were kept in supervised physical rehabilitation program. There were 11 deaths, 2 in HTx, 2 in LVAD, 7 in the rehabilitation group. Mean follow-up among the survivors was 43 months ± 40.6 and it was 12.1±10.3 months in those who died. CPET derived measurements between survivors and non-survivors were as follows: V'O2 peak (mL kg–1 min–1): 12.6±4.6 and 8.6±2.7 (p=0.002); the VO2 AT (mL kg–1 min–1): 9.9±3.3 and 6.1±3.0 (p=0.002); VE/VCO2 slope: 34.2±12.1 and 68.1±68.7 (p=0.0003); R peak: 1.1±0.2 and 1.0±0.1 (p=0.009); t1/2, in seconds: 135.8±47.9 and 170.1±82.0 (p=0.03); HR at the first minute 16.6±13 and 7±5 (p=0.009); OUES (L min–1): 1.1±0.4 and 0.9±0.3 (p=0.04) and CP [(ml O2 kg–1 min–1) mmHg] 1.516.2±689. 3 and 960.6±363.6 (p=0.005). and the relation (VE/VCO2 slope)/V'O2 peak were 3.2±2.0 and 11.4±19.5 (p=0.001), respectively. Conclusion The predisposition to early death could be stratified by V'O2 peak, VO2 of the ventilatory threshold, VE/VCO2 slope, t1/2, recovery HR, OUES, CP, and by the relation (VE/VCO2 slope)/V'O2 peak. Funding Acknowledgement Type of funding source: Private hospital(s). Main funding source(s): own financing