Early and midterm outcome after off-pump and on-pump surgery in Beating Heart Against Cardioplegic Arrest Studies (BHACAS 1 and 2): a pooled analysis of two randomised controlled trials
Cardiac surgery was traditionally performed ’on-pump’, which means that during the operation the heart is stopped and blood is pumped round the body by the heart lung machine (the ‘pump’). At the time of the BHACAS studies, coronary-artery bypass surgery on the beating heart was being used in more and more patients (‘off-pump’). In this operation, the heart continues to beat. However, there were no randomised controlled trial to compare the midterm effects of each type of surgery. We did two randomised trials to compare the short-term morbidity associated with off-pump and on-pump myocardial revascularisation. Our aim was to pool the results to assess midterm outcomes.
From March 1997, to November 1999, we randomly allocated 200 patients to off-pump and 201 to on-pump coronary surgery. In Beating Heart Against Cardioplegic Arrest Study (BHACAS) 1, we excluded patients who had had myocardial infarction in the past month or whose operations were more challenging on the beating heart. In BHACAS 2, we included such patients. Primary outcomes were all-cause mortality and cardiac-related events at midterm follow-up (1-3 years).
Off-pump coronary surgery significantly lowers in-hospital morbidity without compromising outcome in the first 1-3 years after surgery compared with conventional on-pump coronary surgery.
Two to four years after surgery, patients randomised to off- and on-pump had similar symptoms, generic and disease-specific QoL.
Despite this evidence some surgeons were unwilling to adopt off-pump surgery as they were worried about the long-term quality of the bypass grafts performed on the beating heart.
We conducted a follow-up study to BHACAS 1 and 2 to compare long term outcomes in these patients.
Participants were followed up at 6 to 8 years after their operation to assess if the bypass graft had become blocked and if there were any major adverse cardiac-related events, such as heart attack. Their health-related quality of life was also assessed. The bypass grafts were assessed by using multidetector computed tomographic coronary angiographic analysis with a 16-slice scanner (CT scans). Two blinded observers classified proximal, body, and distal segments of each graft as occluded or not. Major adverse cardiac-related events and health-related quality of life were obtained from questionnaires given to participants and family practitioners.
Long-term health outcomes with off-pump coronary artery bypass are similar to those with coronary artery bypass grafting with cardiopulmonary bypass when both operations are performed by experienced surgeons.
A paper for this study is available