Key result
Operated TOF patients show ~18% lower VO2max versus healthy controls.
Why the study?
CPET and CMR are used to time pulmonary homograft replacement in operated TOF patients with significant pulmonary regurgitation, prompting an evaluation of the correlation between CPET and CMR parameters.
How do cardiopulmonary exercise testing parameters correlate with cardiac magnetic resonance parameters in adult operated tetralogy of Fallot patients?
Observational (n=66)
No
How do cardiopulmonary exercise testing parameters correlate with cardiac magnetic resonance parameters in adult operated tetralogy of Fallot patients?
Absolute Event Rate: 29% vs 35.2%
p-value: p=0.001
In adult operated tetralogy of Fallot patients, increased right and left ventricular diastolic volumes unexpectedly correlate with higher VO2max, which may represent adaptive ventricular remodeling.
Supports serial CPET in repaired TOF follow-up; leaves open intervention effects on exercise capacity.
Purpose: Cardiopulmonary exercise testing (CPET) and cardiac magnetic resonance (CMR) are used to time pulmonary homograft replacement in operated TOF patients with significant pulmonary regurgitation (PR). We correlated CPET and CMR parameters in these patients. Methods: Single-centre retrospective analysis of 36 operated TOF patients (post-repair 21±7 yr; 30 NYHA I, 6 NYHA II; age 28±11 yr; 29 males) with at least moderate PR on CMR who underwent CPET within 15 (median 5, IQR 1-7) months of CMR. CPET parameters were compared with 30 age- and sex-matched healthy controls (age 30±10 years, male=24). Results: Peak oxygen consumption (VO2max) (29.0±6.5 vs 35.2±7.3 ml/kg/min, p=0.001) and peak oxygen pulse (POP) (11.6±3.8 vs 13.9±2.9 ml/beat, p=0.008) are significantly lower in TOF group vs control. No significant difference in anaerobic threshold (AT) and VE/VCO2 slope seen. Univariate analyses show negative correlation between PR fraction and AT; positive correlation between indexed left (LV) and right (RV) ventricular end-diastolic volumes and VO2max (see table). These remain significant after age and sex adjustments. RV restriction has no correlation with CPET results. CPET* and CMR correlation in TOF (n=36) *For peak oxygen pulse and VE/VCO2 slope, no significant correlation with CMR. EDVi, indexed end-diastolic volume; ESVi, indexed end-systolic volume; LV, left ventricle; RV, right ventricle; EF, ejection fraction. Conclusions: TOF subjects have near normal exercise capacity but significantly lower VO2max and POP vs controls. Increased PR fraction is associated with lower AT; increased RV and LV diastolic volumes, unexpectedly with higher VO2max. The latter may represent adaptive LV and RV remodeling in well-compensated TOF subjects (whose exercise habits were not studied here).
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Yap et al. (2013) conducted an observational in Operated tetralogy of Fallot with pulmonary regurgitation (n=66). Operated tetralogy of Fallot vs. Healthy controls was evaluated on Peak oxygen consumption (VO2max) (p=0.001). Operated TOF patients had significantly lower peak oxygen consumption compared to healthy controls (29.0 vs 35.2 ml/kg/min, p=0.001).
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