A comparison of survival between on-pump and off-pump left internal mammary artery bypass graft surgery for isolated left anterior descending coronary artery disease: an analysis of the UK National Adult Cardiac Surgery Audit Registry

OBJECTIVES: To determine if the use of cardiopulmonary bypass is associated with all-cause in-hospital and mid-term survival for patients undergoing left internal mammary artery (LIMA) to left anterior descending (LAD) coronary artery bypass grafting (CABG) for single coronary vessel disease.

METHODS: Data from the National Adult Cardiac Surgery Audit registry for all elective and urgent isolated CABG procedures performed between April 2003 and March 2013 in first-time cardiac surgery patients were extracted. Experienced surgeons (those with ≥300 records) were classified by their technique preference (as 'off-pump preference', 'mixed practice', 'on-pump preference') based on their entire isolated CABG data. In-hospital mortality and time to death were analysed using logistic and Cox proportional hazards regression models, respectively.

RESULTS: From a total of 3402 records, 65.5% were performed off-pump. There were 16 (0.47%) in-hospital deaths: 6 (0.51%) in the on-pump group and 10 (0.45%) in the off-pump group. The risk-adjusted odds ratio of in-hospital mortality in the direction of on-pump was 1.09 [95% confidence interval (CI): 0.39-3.04; P = 0.86]. The overall 5-year survival in the on- and off-pump groups was 93.1 and 93.4%, respectively. The adjusted hazard ratio (HR) for mortality in the direction of on-pump CABG was 1.15 (95% CI: 0.89-1.49; P = 0.28). Comparing off-pump cases performed by experienced CABG surgeons with a preference for the off-pump technique with on-pump cases performed by surgeons with a preference for the on-pump technique indicated a significant difference (HR for on-pump = 1.72; 95% CI: 1.19-2.47; P = 0.004).

CONCLUSIONS: Elective and urgent first-time CABG for isolated LAD disease is associated with excellent mid-term survival in the England and Wales population, conferring a 5-year survival rate of 93.1 and 93.4% in the on-pump and off-pump groups, respectively. There was no difference in risk-adjusted survival between the on-pump and off-pump techniques when analysing all procedures; however, supportive analysis demonstrated that off-pump surgery performed by experienced surgeons with a preference for the off-pump technique in their CABG caseload is associated with improved mid-term survival when compared with on-pump surgery performed by surgeons with a preference for the on-pump technique.