Does off-pump coronary artery bypass surgery reduce mortality in high risk patients?

Background: The aim of this retrospective study was to compare outcome in two groups of patients who were classified according to their risk groups and underwent coronary revascularization with or without cardiopulmonary bypass.

Material And Methods: Between January 1996 and July 2000, 480 cases that underwent coronary artery bypass surgery (CABG) were included in a retrospective nonrandomized manner for study. Group 1 included 210 patients who were revascularized using off-pump techniques. Octopus 2 and 3 (Medtronic, Inc., Minneapolis, MN) were used for tissue stabilization. Group 2 included 270 cases who underwent CABG using CPB. Emergency cases, combined operations, reoperations, and patients in cardiogenic shock were excluded. Demographic variables were comparable between two the groups. Using the Allegheny Clinic Risk Scoring Scale [Magovern 1996], patients in both groups were scored as low, moderate, and high risk. In Group 1, 37 % of patients consisted of high risk patients while Group 2 had 14% (p < 0.05). Student's t-test and chi-square test were used for statistical analysis and alfa < 0.05 was considered significant.

Results: Mortality was 1.4% in Group 1 and 1.5% in Group 2 (p = ns). Mean anastomosis per patient was 2.6 +/- 0.6 in Group 1 and 3.2 +/- 0.5 in Group 2 (p < 0.05). Patients in Group 1 needed less blood transfusions and less inotropic support postoperatively (p < 0.05). There were also fewer minor neurological events (p < 0.05) and pulmonary complications (Type 2) in Group 1. Atrial fibrillation rate, infection, and major neurological deficit (Type 1) were similar in both groups. Mortality was less among Group 1 high risk patients (3.9 %) in comparison to Group 2 high risk patients (7.9 %), but this did not reach statistical significance.

Conclusions: In low or moderate risk patients, CABG can be performed safely with or without CPB. In high risk patients with several comorbidities, off-pump CABG seems to be a safe and efficient method that can improve outcome.