Late Anatomic Findings after “Rescue CABG” for Peri-Operative Ischemia Following Aortic Root Replacement

Abstract

Background: Acute myocardial ischemia, seen in about 2% of aortic root replacements (ARR), is acutely life-threatening, manifesting as failure to wean from bypass, ventricular fibrillation, or unstable hemodynamics. The exact precipitating anatomic cause is usually not apparent at the time of surgery. In this report, we take advantage of late computed tomographic (CT) angiograms of long-term survivors of peri-operative ischemia after ARR to determine what abnormalities of the coronary button reattachments produced the peri-operative ischemia. Methods: The database of the Aortic Institute at Yale-New Haven was reviewed to identify all patients undergoing ARR over a 15-year period. Operative records, patient charts, and CT angiograms of patients who had peri-operative ischemia were reviewed in detail, including analysis by an imaging specialist. Results: 271 patients underwent ARR, 220 with mechanical and 51 with biological valved conduits. Hospital mortality was 2.95%. Clinical follow-up ranged from 1 to 182 months. Survival in discharged patients was 97.7% at 5 years and 95.2% at 7 years. Peri-operative ischemia was seen in 4 of 271 patients (1.5%). All four affected patients survived-with interventions including supplemental coronary bypass grafts (4 patients), intra-aortic balloon pump placement (2 patients), and left ventricular assist device insertion (1 patient). Late CT angiograms revealed severe but non-obstructive left main calcification serving as a focal point for coronary angulation in 2 patients, angulation without calcification in 1 patient, and totally normal anatomy in 1 patient. Conclusions: Myocardial ischemia after ARR is rare but acutely life-threatening. Prompt recognition and treatment by supplemental coronary artery bypass grafting preserves life and leads to good late survival. Intramural calcification (non-obstructive) of the distal left main coronary artery predisposes to angulation after coronary button creation and should be a "red flag" for this potential problem.