Off-pump coronary bypass surgery and all arterial conduits: learning experience at Bangkok Heart Institute

Off-pump coronary artery bypass technique or bypass graft surgery without the use of a heart-lung machine has been introduced in the last six years, and now comprises approximately 25 per cent of all coronary artery bypass surgery being done in the world. One of the goals of beating heart surgery is to eliminate the complications associated with the use of cardiopulmonary bypass. The use of all arterial conduits for coronary artery bypass graft has become more acceptable after experiences gained and reports of better long-term results. From January 2001 to December 21 2002 the authors performed 251 off-pump procedures. One hundred and nine of these cases were done utilizing all arterial conduits. The data was stratified using the US National Society of Thoracic Surgeons Cardiac Surgery Database pre-operative risk module and divided into 3 groups as suggested: Low risk group with a predicted mortality of 0-1 per cent (2 patients); Medium risk group with a predicted mortality of 2-9 per cent (87 patients), and High risk group with a predicted mortality of 10+ per cent (10 patients). The predicted mortality of the entire group was 4.5 per cent. There were 90 males and 19 females with a mean age of 60.2 +/- 10.7 years, with 15.6 per cent of them older than 70 years. Pre-operative co-morbidities included 1/4 of the patients who had ejection fraction (EF) of equal to or less than 0.4, 4.5 per cent had unstable angina, 1.6 per cent had urgent/emergent status, 26.6 per cent underwent re-operative procedure, 1 per cent had pre-operative serum creatinine more than 2 mg per cent, 4.8 per cent had a history of stroke, 20.2 per cent had a history of congestive heart failure, 45.2 per cent had a history of previous myocardial infarction, 10.7 per cent had a history of chronic obstructive pulmonary disease, 46.9 per cent had a history of diabetes, 62 per cent had hypertension, and 20 patients (18.3%) required intra aortic balloon pump. Intra-operative parameters revealed 3.7 +/- 1.3 grafts/patient. The left internal mammary artery (LIMA) was used to the left anterior descending (LAD) in 6.4 per cent, or sequential with the diagonals 93.6 per cent. The 30 days mortality was 3.6 per cent (4 cases). Further analysis revealed that pre-operatively, none of these 4 cases was in the low predicted (predicted mortality of 0-1%) risk group, 2 of them were in the medium (predicted mortality of 2-9%) and the other 2 were in the high predicted risk (predicted mortality of 10+%) group. The skin-to-skin time was 4.1 hours and there were two conversions to on-pump in this group. Post-operatively, the intubation time was 4.7 hours. There was no peri-operative myocardial infarction, one patient required dialysis, and no patient experienced stroke. There was no sternal wound or arm wound infection, 9.5 per cent experienced temporal sensation impairment at the site of the radial artery harvesting at one month. Re-operation for bleeding occurred in 3 cases, and thirteen patients (14.3%) developed new atrial fibrillation. The authors are no longer making a one-foot long incision and spread ten inches wide like in the old days'. With the less invasive approach lessened in the recent past, the authors have found the less invasive the incision the less the pain after surgery. Totally eliminating the leg incision has allowed the patient to get up and mobilize on the same afternoon, if the procedure was done in the morning. All of these approaches combined with the off-pump technique, as far as the authors are concerned, will provide those who need coronary arterial bypass graft the best operative procedure.