Exercise capacity among patients with tetralogy of Fallot who underwent transannular and non-transannular repair.

BACKGROUND

Tetralogy of Fallot (TOF) repair using a transannular patch (TAP) may lead to varying degrees of pulmonary insufficiency (PI) due to loss of pulmonary valve integrity. The subsequent right ventricle (RV) dilatation and dysfunction over time may directly or indirectly affect exercise capacity.

METHODS

Fifty-six patients who had undergone intracardiac repair of TOF between January 2010 and December 2015 were subjected to exercise stress testing. Twenty-six patients underwent TAP placement, and 30 patients did not. The modified BRUCE protocol was used on a standard cycle ergometer for exercise testing. The total duration of exercise, the heart rate achieved at the peak of exercise, the heart rate reserve, and the maximal oxygen consumption (VO2 max) in patients in the TAP repair group were compared to those in the non-TAP group.

RESULTS

Patients with a TAP had significantly lower exercise capacity compared to those without TAP. Both the total duration of exercise, the heart rate achieved at the peak of exercise, the heart rate reserve, and the VO2 max were higher in patients in the TAP repair group compared to the non-TAP group. The VO2 max in the non-TAP group was higher (37.47 ± 5.7 ml/kg/min) than that of the TAP group (30.5 ± 5.0 ml/kg/min) (P = 0.02). Multivariate analysis showed that neither TAP nor PI was predictive of exercise capacity. However, we found that RV function and overall health status were significant predictors of exercise capacity.

CONCLUSIONS

The non-TAP group had a better VO2 max, heart rate recovery time, and heart rate reserve than the TAP group at 5 years of follow-up.