Heart Bypass Imaging Helps Reduce Graft Defects

The technique for coronary artery bypass graft (CABG) surgery has largely remained the same over the last 35 years, including closing the chest without really knowing whether the bypass grafts are potentially kinked, constricted, or otherwise impaired.

Performing standard angiography after CABG surgery, but before the patient leaves the operating room (OR), can help identify defects and allow surgeons to correct most of them before closing, according to Vanderbilt [University] Heart and Vascular Institute (VHVI; Nashville, TN, USA) researchers.

David Zhao, M.D., and colleagues conducted a study to report their experience with routine completion angiogram after CABG and percutaneous coronary intervention (PCI). Their findings will be published in the January 20, 209, issue of the Journal of the American College of Cardiology (JACC).

The study team collected data on 336 consecutive patients who underwent CABG surgery either by conventional surgical bypass or hybrid CABG and percutaneous intervention. The patients were treated in Vanderbilt's unique hybrid OR, which combines a cardiac catheterization laboratory with an operating room. Technical defects are thought to be largely responsible for graft failure rates ranging from 7-30%. "We believe that imaging our results may improve short-term and long-term graft patency,” said John Byrne, M.D., professor of cardiac surgery and chair of the department.

In the study, an interventional cardiologist or a surgeon under the supervision of a cardiologist, performed coronary graft angiography. If the angiogram identified defects, the physician made revisions either surgically or percutaneously. They repeated the angiography to ensure correction of these defects before closing the chest.

Among the 796 CABG grafts, 97 (12%) angiographic defects were identified. Defects included chest tube obstruction and kinks in vein grafts, among others. "What we have described is a very simple idea: measuring what we do. We have created an environment to give surgeons immediate feedback regarding graft quality. This could have been done many years ago, but the logistical and political barriers must have been too much at that time. Today, in the collaborative culture we have created at VHVI, this is not just possible, but routine,” Dr. Byrne said.

Except for CABG surgery, every major cardiovascular intervention is accompanied by before and after images to confirm procedural success. Vanderbilt's hybrid OR combines the tools of interventional cardiology and cardiac surgery into one procedural suite.

"Completion angiography provides immediate feedback on issues that were difficult to appreciate with the naked eye,” said Marzia Leacche, M.D., a clinical fellow in the department of cardiac surgery. "Doctors became more aware of the significance of apparently minor defects.”

The scientists believe that routine completion graft imaging should become the standard of care in CABG surgery, but it is only possible by combining the tools of surgery with the tools of interventional cardiology. A second focus of the study evaluated whether conventional CABG patients had different outcomes than patients in whom the hybrid approach was used. The mortality rate was no different between the two groups.

"At Vanderbilt, we combined the best of both worlds by doing hybrid revascularization. This study not only provides the compelling evidence that the hybrid approach is feasible and safe, but embodies the collaborative efforts from many disciplines in the Vanderbilt Heart and Vascular Institute,” concluded Dr. Zhao, associate professor of medicine and director of the Cardiac Catheterization Laboratory and Interventional Cardiology.

Related Links:
Vanderbilt Heart and Vascular Institute