Exercise capacity is a modifiable factor in patients with CHD that has been related to surgical outcomes in adults. We hypothesised that this was true for children undergoing surgical pulmonary valve replacement; therefore, the relationship of preoperative percent predicted peak oxygen consumption to surgical outcomes as measured by total hospital length of stay was explored.
Methods: Single centre retrospective cohort study of patients aged 8-18 years who underwent surgical pulmonary valve replacement. The primary predictor was preoperative percent predicted peak oxygen consumption, and primary outcome was total hospital length of stay. Clinical, imaging, and cardiopulmonary exercise test data were reviewed and compared to total hospital length of stay. Cox proportional hazards regression was used to examine the association between total hospital length of stay and percent predicted peak oxygen consumption.
Results: Three-hundred and seventy patients undergoing pulmonary valve replacement/conduit change between 2003 and 2017 at Boston Children's Hospital were identified. Ninety had preoperative cardiopulmonary exercise tests within 6 months of surgery. Exclusion for inadequate exercise data (n = 3) and imaging data (n = 1) left 86 patients for review. Patients with percent predicted peak oxygen consumption ≥ 70% (n = 46, 53%) had shorter total hospital length of stay (4.4 days) than the 40 with percent predicted peak oxygen consumption <70% (5.4 days, p = 0.007). Median percent predicted peak oxygen consumption increased over sequential surgical eras (p < 0.001), but total hospital length of stay did not correlate with surgical era, preoperative left ventricular function, or preoperative right ventricular dilation.
Conclusion: Children undergoing surgical pulmonary valve replacement with better preoperative exercise capacity had shorter total hospital length of stay. Exercise capacity is a potentially modifiable factor prior to and after pulmonary valve replacement. Until more patients systematically undergo cardiopulmonary exercise tests, the full impact of optimisation of exercise capacity will not be known.
Keywords: Exercise; congenital heart; outcomes; pulmonary valve replacement; tetralogy of Fallot.