Coronary artery compression during intervention on dysfunctional right ventricular outflow tracts

Background: Interventions on dysfunctional right ventricular outflow tracts (RVOT) with stent implantation and/or percutaneous pulmonary valve implantation (PPVI) can cause coronary artery compression (CAC). Coronary angiography during simultaneous test balloon dilation of the RVOT is recommended to diagnose CAC prior to stent placement or PPVI. This study aimed to evaluate a single-institution experience with CAC during RVOT interventions. Methods: This was a retrospective review of all patients referred for intervention on a dysfunctional RVOT (obstruction and/or regurgitation), who had simultaneous balloon dilation and coronary angiography between 8/2010 and 6/2015. Coronary anatomy was assessed by angiography and reported as normal or abnormal. Variable means were compared with t-test, and frequencies with odds ratio (OR). Results: A total of 110 patients were referred for RVOT intervention. The most common diagnoses were tetralogy of Fallot/pulmonary atresia (76%), truncus arteriosus (8%), and aortic stenosis with Ross procedure (8%). Seventy-four patients (67%) had PPVI, 7 (6%) had conduit stent implantation alone, and 29% had balloon dilation (27%). Fifteen of the 110 patients (14%) had evidence of CAC during balloon dilation of the conduit. There were no significant differences between those with CAC and those without, other than incidence of abnormal coronary arrangement (Table). Patients with CAC were more likely to have an abnormal coronary arrangement (27% vs. 6%, OR 5.4, CI 1.3-22.1, p = 0.02). Five patients proceeded with PPVI or RVOT stent despite CAC seen on angiography. Of these, 3 had dynamic systolic CAC remote from the conduit due to high right ventricular pressure, which resolved with relief of conduit obstruction in all 3 (Figure 1A). The other 2 had true compression of a small conal branch from right coronary artery by the conduit, which was intentionally sacrificed to achieve improved RVOT function (Figure 1B). Both of these patients are doing well clinically without RV dysfunction or arrhythmias. Ten patients did not have PPVI or stent placement due to CAC (6 right main, 4 left anterior descending, and 1 conal branch, Figure 1C). Ventricular tachycardia occurred in 1 patient with test balloon dilation. No other complications occurred. Conclusions: Patients with compression of a conal branch with negligible myocardial distribution can be considered for intervention. Dynamic systolic compression due to right ventricular hypertension