Midterm outcomes of patients undergoing aortic valve replacement after previous coronary artery bypass grafting

Abstract

Redo cardiac surgery for aortic valve replacement (AVR) after previous coronary artery bypass grafting (CABG) is technically challenging and carries a high incidence of peri-operative complications. However, experience in the field continues to evolve generating reproducible, and increasingly safer results. We anticipate an increased future role for catheter-based valve procedures and review our operative results to maintain current surgical outcomes for comparison. A retrospective review was conducted from 1996 through 2010 of patients undergoing AVR as a re-operation after previous CABG. Data were obtained through query of the Society of Thoracic Surgeons (STS) database and chart review. Patient outcomes were compared with STS-predicted risk scores. One hundred and thirty-two patients met inclusion criteria (male 83%, female 17%). Average age was 76 (± 7). Thirty-seven patients (28%) required concomitant CABG. Average ejection fraction was 45 (± 14). Comorbid conditions included: diabetes 37% (49/132), hypertension 87% (115/132), NYHA class III/IV 83% (110/132), smoking 51% (67/132), chronic obstructive pulmonary disease 21% (27/132), history of myocardial infarction 61% (80/132), renal failure 16% (21/132) and peripheral arterial disease 38% (50/132).Operative (30-day + hospital) mortality was 6.1% (8/132; 95% CI = 2.9-12.0%), and 30-day mortality was 3.8% (5/132; 95% CI = 1.4-9.1%). One, three and five-year survival rates were 86, 74 and 62%, respectively. Complication rates were as follows: re-operation for bleeding 2.3% (3/132), permanent stroke 0.8% (1/132), prolonged ventilator requirement 18.2% (24/132), deep sternal wound infection 0% (0/132; CI = 0.0-3.5%) and renal failure 9.1% (12/132; none required dialysis). The mean STS-predicted mortality risk score was 7.8% for 111 (applicable) patients for whom actual operative (30-day + hospital) mortality was 3.6%. Low initial operative mortality suggests that surgery is safe and reproducible. However, older age and multiple comorbidities in this patient population may significantly influence late outcomes. The data reported in this study: (i) support open surgical technique as a safe, reliable approach for redo AVR in patients who have undergone previous CABG, and (ii) add to the large body of evidence suggesting that STS scores overestimate risk.