Impacts of valve intervention on the Functional REServe of the Heart: The FRESH-valve pilot study

Severe valve lesions require corrective interventions to avoid progression to heart failure (HF) and premature demise. We tested the hypothesis that despite operative risks, corrective valvular interventions will lead to significant improvements in overall cardiac pump function, especially before the onset of cardiac decompensation.

We compared the cardiopulmonary exercise performance and non-invasive haemodynamics of 46 consecutive patients with severe valvular disease before and after valvular intervention with reference to 101 healthy male and 139 female controls without cardiovascular disease. Cardiac and physical functional reserves were measured with standard respiratory gas analyses and CO2 rebreathing to measure cardiac output non-invasively during peak treadmill exercise. Data are given as mean ± SD and statistical significance accepted at P<0.05.

The entire patient cohort showed no significant improvement in peak O2 consumption (V˙O2max, P=0.74) or in peak cardiac power (CPOmax, P=0.34) after valvular intervention, but we found instead a dichotomous outcome depending on preoperative cardiac function: (i) the pre-operative cardiac decompensatory subgroup (LoW, n=26) showed increased CPOmax (2.63 ± 0.67 to 3.42 ± 0.98 W, P<0.0001) and V˙O2max (1.38 ± 0.55 to 1.56 ± 0.59 L·min(-1), P<0.01); and (ii) the pre-operative non-decompensatory subgroup (HiW) showed reduced CPOmax (4.58 ± 0.96 to 3.84 ± 0.92 W, P<0.001) and V˙O2max (2.29 ± 0.72 to 1.97 ± 0.75 L·min(-1), P<0.01). Changes in NYHA class were found to be discrepant with these objective measurements.

This investigation found an unexpected finding that valvular interventions performed in routine clinical practice do not consistently improve cardiac function, especially in those without pre-operative cardiac decompensation. Assessing cardiac functional gains would open up new avenues for future trials of valvular interventions.