Pulmonary Effects on Exercise Testing in Tetralogy of Fallot Patients Repaired with a Transannular Patch

Background: A transannular patch is often used in the contemporary surgical repair of tetralogy of Fallot. This can lead to significant pulmonary insufficiency and increased right ventricular volumes and ultimately pulmonary valve replacement. Cardiopulmonary exercise testing is used to assess exercise capacity in tetralogy of Fallot patients before pulmonary valve replacement. There is only few published literatures on how lung function affects functional capacity in tetralogy of Fallot patients repaired with a transannular patch.

Methods: A retrospective chart review was done from 2015 to 2017 on patients with tetralogy of Fallot who underwent maximal effort cardiopulmonary exercise testing with cycle ergometry and with concurrent pulmonary function testing. Tetralogy of Fallot patients repaired with a transannular patch without pulmonary valve replacement were compared with age, gender, and size-matched normal controls.

Results: In the tetralogy of Fallot group, 24 out of 57 patients underwent primary repair with a transannular patch. When compared to the normal controls, they demonstrated abnormal predicted forced expiratory volume in one second (79 ± 23.1% versus 90.7 ± 14.1%, p<0.05), predicted maximal voluntary ventilation (74 ± 18% versus 90.5 ± 16.2%, p<0.05) while having low-normal predicted forced vital capacity (80.5 ± 17.2% versus 90.2 ± 12.4%, p<0.05) and normal breathing reserve percentage (50.3 ± 11.3% versus 47.5 ± 17.3%, p = 0.52). Cardiopulmonary exercise testing abnormalities included significantly lower percent predicted oxygen consumption (63.2 ± 12.2% versus 87 ± 12.1%, p<0.05), maximal heart rate (171.8 ± 18.9 versus 184.6 ± 13.6, p<0.05), and percent predicted maximum workload (61.7 ± 15.9% versus 88.3 ± 21.5%, p<0.05).

Conclusions: Tetralogy of Fallot patients repaired with a transannular patch can have abnormal pulmonary function testing with poor exercise capacity in addition to chronotropic incompetence and impaired muscular power.