Does a bidirectional Glenn shunt improve the oxygenation of right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum?

Objective: There is a risk of myocardial ischemia in patients with pulmonary atresia and intact ventricular septum associated with the right ventricle-dependent coronary circulation. In this patient group, the oxygen delivery to the myocardium depends on the oxygen saturation of the right ventricular cavity. We hypothesized that bidirectional Glenn shunt would improve the oxygenation of right ventricle-dependent coronary circulation relative to a systemic-pulmonary artery shunt. The reduction of systemic venous return to the right atrium due to a bidirectional Glenn shunt could increase the oxygen saturation of the right ventricle in the clinical setting, when the mixture of systemic and pulmonary venous blood is unchanged at the atrial level.

Methods: Patients with right ventricle-dependent coronary circulation were defined as those with right ventricle-coronary artery fistulas plus stenoses of the right or left coronary arteries. For 7 patients with right ventricle-dependent coronary circulation before and after bidirectional Glenn shunt, cardiac catheterization was performed and the oxygen saturation of the right ventricular cavity was measured.

Results: For all 7 patients, the bidirectional Glenn shunt was performed at a mean age of 18 months. Ischemic changes in the electrocardiogram before the bidirectional Glenn shunt improved after the procedure in 2 patients. The oxygen saturation of the right ventricular cavity before the bidirectional Glenn shunt was 54.6 +/- 8.8%, and that after the BGS significantly increased to 75.6% +/- 5.8% (P < .01). All 7 patients have subsequently undergone the Fontan procedure with excellent results.

Conclusion: Early bidirectional Glenn shunt could prevent progression of myocardial ischemia in pulmonary atresia with intact ventricular septum with right ventricle-dependent coronary circulation.