Abstract
Introduction
The role of cardiopulmonary exercise testing (CPET) is unquestionable to assess prognosis in heart failure. In patients with valvular heart disease (VHD), the functional capacity (FC) is crucial to aid in the right timing of surgery. The aim of this study was to compare the assessment of the FC by CPET and NYHA and the correlation between ventilatory efficiency parameters and resting systolic pulmonary artery pressure (SPAP).
Methods
We studied 100 VHD patients (57% female) who underwent a CPET. We calculated the real METS (RM) as indexed peak VO2/3.5 (1 MET=3.5 ml O2/kg/min) and compared to estimated METS (EM) derived by the time of exercise. An agreement analysis between RM, EM and NYHA was calculated. The correlation among VE/Vslope CO2, EqCO2at anaerobic threshold (AT), PETCO2, partial pressure end-tidal CO2 at AT and SPAP was analyzed.
Results
The results are shown in Table and Figure. The RM and the EM were 4.7±1.7 and 5.5±3, respectively (p<0.01) with a low agreement (ICC=0.6, p<0.01). The agreement between NYHA and the classification obtained from peak % of predicted peak VO2 was very low (weighted kappa =0.06, p=0.28). In patients with severe mitral VHD, the ventilatory efficiency parameters were correlated with SPAP (PETCO2 (AT), r=−0.7, p=0.002; EqCO2 (AT), r=0.5, p=0.04:VE/Vslope CO2, r=0.3, p 0.2), whereas in those with severe aortic VHD, these correlations were much lower (PETCO2 (AT), r=−0.3, p=0.13; EqCO2 (AT), r=0.2, p=0.15; VE/Vslope CO2, r=0.18, p 0.31).
Total (n=100) Mitral regurgitation (n=35) Aortic regurgitation (n=23) Age 65 (29–86) 66 (30–84) 65 (11–87) LVEF (%) 62±6 63±6 61±7 SPAP (mmHg) 40±11 39±11 36±8 NYHA I (60%), II (33%), III (7%) I (63%), II (29%), III (9%) I (63%), II (33%), III (4%) Indexed peak VO2 (ml/min/kg) 16±6 17±6 19±8 Peak % predicted VO2 73±18 74±17 79±18 Predicted VO2 AT (%) 58±19 54±19 61±22 Eq CO2 AT 33±6 32±7 32±5 VE/VSlope CO2 33±6 32±7 33±8 PetCO2 AT 34±4 36±4 36±5
Type and degree of VHD
Conclusions
NYHA scale and estimation of METS derived from the time of exercise clearly overestimated the FC of our population. In our series, the ventilatory inefficiency in patients with mitral VHD could be a surrogate marker of advanced disease and could lead to an earlier intervention.
Cardiopulmonary exercise testing early after stroke using feedback-controlled robotics-assisted treadmill exercise: test-retest reliability and repeatability