Cardiac magnetic resonance versus routine cardiac catheterization before bidirectional Glenn anastomosis: long-term follow-up of a prospective randomized trial.

Objectives: A previously published randomized clinical trial comparing cardiac magnetic resonance (CMR) versus routine catheterization in patients with functional single ventricle before bidirectional Glenn (BDG) operation demonstrated similar short-term post-BDG outcomes. We sought to assess late outcomes in this cohort to ascertain any long-term effects of this evaluation strategy.

Methods: Retrospective review of enrolled patients through most recent follow-up was performed on all 82 patients in the original cohort, at a median age of 8.8 years.

Results: Of these, 76 (93%) underwent Fontan operation; 2 died before Fontan. Baseline demographics, anatomic factors, and age at BDG did not differ between those randomized to CMR versus catheterization. Although pre-BDG CMR patients were younger at Fontan (2.4 vs 2.7 years; P = .02), baseline weight, body surface area, oxygen saturation, ventricular function, and degree of atrioventricular valve regurgitation were similar. Catheterization before Fontan (n = 76) demonstrated similar hemodynamic parameters including pulmonary vascular resistance and mean pulmonary artery, atrial, and ventricular end-diastolic pressures. CMR patients had comparable rates of transcatheter interventions (71% vs 79%; P = .6), including coil occlusion of systemic-pulmonary collaterals (66% vs 61%; P = .29). At Fontan surgery, short-term complications, hospital length of stay, and the percent meeting a 5-part definition of successful Fontan operation were not different (71% vs 55%; P = .23).

Conclusions: Pre-BDG CMR and catheterization groups had equivalent clinical and hemodynamic profiles before Fontan and similar post-Fontan outcomes at a median follow-up of 8 years after BDG. For selected patients, a pre-BDG evaluation with CMR is an acceptable alternative to catheterization.