NEW YORK (Reuters Health) – Performing coronary artery bypass graft (CABG) surgery in high-risk patients without placing them on cardiopulmonary bypass does not increase their risk of short-term complications, a new article reports.

On the other hand, it doesn’t appear to provide any short-term benefits, either.

Until now, randomized trials comparing CABG with and without cardiopulmonary bypass have been done in low-risk patients, according to a paper by Dr. Christian H. Moller and colleagues from Copenhagen University Hospital in the February 2 issue of Circulation.

The researchers note that off-pump CABG was safe and effective in these earlier studies, although there was no difference in mortality, myocardial infarction or stroke relative to CABG using bypass. Observational studies, however, have suggested that off-pump CABG may have advantages in high-risk patients.

To investigate, the authors randomly assigned 341 patients undergoing CABG for 3-vessel disease, with a EuroSCOREs of 5 or above, to a bypass group or no-bypass group. There was no difference between groups in the number of grafts. Only 5 of the patients were younger than 65 years, and nearly 20% were diabetic.

At 30 days, rates of the composite primary outcome of adverse cardiac and cerebrovascular events (all-cause mortality, acute myocardial infarction, cardiac arrest with successful resuscitation, cardiogenic shock, stroke, and coronary reintervention) were similar in the two groups (15% for off-pump vs. 17% for on-pump), as were rates of individual postoperative outcomes, including renal complications, new-onset atrial fibrillation, time to extubation, and length of ICU and hospital stays.

With regard to intra-operative factors, the only difference was in the mean number of grafts in the lateral area of the left ventricle (0.97 off-pump vs 1.14 on-pump). Anastomosis in this part of the heart is “troublesome” without bypass, Dr. Moller and his colleagues note. “Whether surgeons performing off-pump surgery in general have a tendency to assess a coronary artery unfeasible for grafting due to severe atherosclerosis or desist from grafting for technical reasons is unclear,” they write.

The researchers conclude that “off- and on-pump CABG can be performed in high-risk patients with low short-term complications.”

But, they add, “Off-pump CABG may carry a risk of incomplete revascularization of the lateral territory of the left ventricle, which could affect long-term prognosis.”

Reference:
Circulation 2010;121:498-504.