ORLANDO — Performing a coronary artery bypass graft without the aortic clamp appears to minimize the risk of postoperative cerebrovascular accidents independent of the use of cardiopulmonary bypass, said Dr. Michael F. Gibson at the annual meeting of the Southern Thoracic Surgery Association.
Neurologic dysfunction is a common complication after cardiac surgery. Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthesia management, central nervous system complications occur in a large number of patients undergoing surgery requiring CPB, he said.
Many comparisons between traditional arrested-heart coronary artery bypass graft (CABG) and off-pump coronary artery bypass (OPCAB) have therefore concentrated on the contribution of the cardiopulmonary bypass machine to the potential adverse outcomes, said Dr. Gibson, of the University of Oklahoma Health Sciences Center, Oklahoma City.
In contrast, in a recent investigation, Dr. Gibson and his colleagues evaluated the clinical neurologic outcomes in patients undergoing arrested-heart CABG, beating-heart cardiopulmonary bypass CABG (BHCAB), and OPCAB in whom no aortic clamp was used to restrict blood flow to the graft area.
The study included 424 patients who underwent coronary artery bypass surgery at the Health Sciences Center between July 2000 and April 2004. All the procedures were performed without the placement of an aortic clamp, and all were started as OPCAB and converted to BHCAB as required by the clinical situation, he said.
Of the 424 patients, 213 underwent CABG, 134 underwent OPCAB, and 77 underwent BHCAB. During the study period, no BHCAB or OPCAB patients were converted to CABG.
All of the patients were evaluated post operatively for clinical neurologic outcomes. Of the patients, six who underwent CABG and none who underwent BHCAB or OPCAB experienced clinically obvious cerebrovascular accidents (CVAs) in the immediate postoperative period.
“The fact that there were no immediate postoperative CVAs in the off-pump and beating-heart CPB patients implies that the application of the aortic clamp, rather than the use of cardiopulmonary bypass, is the more important culprit for such adverse outcomes in CABG surgery,” said Dr. Gibson. “Routine clampless surgery minimizes the CVA risk and may be the most important improvement that is easily obtainable with the use of off-pump and beating-heart surgery techniques.”