Patients with ischaemic heart disease due to narrowing of coronary arteries can be treated with coronary artery bypass surgery. Coronary artery bypass surgery has traditionally been performed with cardiopulmonary bypass and an arrested heart. Development of cardiac stabilisers have made it possible to conduct the operation on the beating heart and thereby avoid cardiac arrest and cardiopulmonary bypass. By avoiding cardiac arrest and cardiopulmonary bypass, it was hoped that complications seen after coronary artery bypass could be reduced. Systematic review of 86 randomised clinical trials including 10,716 patients and statistical analyses of the data showed that coronary artery bypass surgery performed on the beating heart results in an increased risk of death. No firm evidence for benefit or harm was found regarding the outcome measures myocardial infarction, stroke, atrial fibrillation, renal insufficiency, or coronary reintervention. Our data raises a warning regarding coronary artery bypass surgery on the beating heart and cardiac arrest and cardiopulmonary bypass seem less risky. In patients with contraindications for cannulation of the aorta and cardiopulmonary bypass coronary artery bypass surgery on the beating heart may be a solution but we need randomised clinical trials in these patients to identify the most beneficial approach.
Our systematic review did not demonstrate any significant benefit of off-pump compared with on-pump CABG regarding mortality, stroke, or myocardial infarction. In contrast, we observed better long-term survival in the group of patients undergoing on-pump CABG with the use of cardiopulmonary bypass and cardioplegic arrest. Based on the current evidence, on-pump CABG should continue to be the standard surgical treatment. However, off-pump CABG may be acceptable when there are contraindications for cannulation of the aorta and cardiopulmonary bypass. Further randomised clinical trials should address the optimal treatment in such patients.
Coronary artery bypass grafting (CABG) is performed both without and with cardiopulmonary bypass, referred to as off-pump and on-pump CABG respectively. However, the preferable technique is unclear.
To assess the benefits and harms of off-pump versus on-pump CABG in patients with ischaemic heart disease.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 1, 2011), MEDLINE (OVID, 1950 to February 2011), EMBASE (OVID, 1980 to February 2011), Science Citation Index Expanded on ISI Web of Science (1970 to February 2011) and CINAHL (EBSCOhost, 1981 to February 2011) on 2 February 2011. No language restrictions were applied.
Randomised clinical trials of off-pump versus on-pump CABG irrespective of language, publication status and blinding were selected for inclusion.
For statistical analysis of dichotomous data risk ratio (RR) and for continuous data mean difference (MD) with 95% confidence intervals (CI) were used. Trial sequential analysis (TSA) was used for analysis to assess the risk of random error due to sparse data and to multiple updating of accumulating data.
Eighty-six trials (10,716 participants) were included. Ten trials (4,950 participants) were considered to be low risk of bias. Pooled analysis of all trials showed that off-pump CABG increased all-cause mortality compared with on-pump CABG (189/5,180 (3.7%) versus 160/5144 (3.1%); RR 1.24, 95% CI 1.01 to 1.53; P =.04). In the trials at low risk of bias the effect was corroborated (154/2,485 (6.2%) versus 113/2,465 (4.5%), RR 1.35,95% CI 1.07 to 1.70; P =.01). TSA showed that the risk of random error on the result was unlikely. Off-pump CABG resulted in fewer distal anastomoses (MD -0.28; 95% CI -0.40 to -0.16, P <.00001). No significant differences in myocardial infarction, stroke, renal insufficiency, or coronary re-intervention were observed. Off-pump CABG reduced post-operative atrial fibrillation compared with on-pump CABG, however, in trials at low risk of bias, the estimated effect was not significantly different.