Background .– Coronary compression (CC) may occur during percutaneous pulmonary valve implantation (PPVI) and is potentially life threatening when undiagnosed before right ventricular outflow tract (RVOT) stenting. We sought to evaluate its incidence, diagnosis and outcome.

Methods .– All consecutive patients who underwent transcatheter RVOT treatment from May 2008 to December 2011 in two institutions were studied. Baseline demographics, diagnosis and outcomes of CC were reviewed with analysis of risk factors.

Results .– CC occurred in six out of 100 patients (6%) at a median age of 24 (13 to 49) years, with RVOT conduit stenosis as the primary lesion in all cases. The initial congenital heart disease was pulmonary atresia-ventricular septal defect ( n = 3), complex transposition of the great arteries ( n = 2) and critical aortic stenosis status-post Ross operation ( n = 1). The RVOT initial median conduit diameter at surgical implantation was 23 (17 to 24) mm and conduit types were homograft ( n = 3), bioprothesis ( n = 2) and a pericardial patch ( n = 1). CC was diagnosed by coronary angiogram during balloon dilation of the RVOT in all cases whereas it was suspected on pre-procedure computed tomography (CT-scan) in only two cases. Compression occurred on the left anterior descending coronary artery in four cases and on a right coronary artery that arose from the proximal left anterior descending coronary artery in two patients (single coronary artery). No risk factor was found but there was a significantly higher incidence of CC in one of the two institutions ( P = 0.04). CC was well-tolerated and resolved after the balloon was deflated in all the cases. No patients underwent RVOT stenting or PPVI. Surgical conduit replacement was electively performed in three patients. Two patients with moderate residual RVOT stenosis are followed. One patient with encephalopathy and respiratory insufficiency died 9 months after catheterization.

Conclusions .– CC is efficiently diagnosed by coronary angiogram during balloon dilation in patients undergoing transcatheter interventions on RVOT. Diagnosis by pre-procedure CT-scan is not accurate. No specific risk factors exist. Surgical conduit replacement is indicated when balloon dilation fails to improve the RVOT obstruction.