ACC 2013: Worse long-term clinical outcomes in patients with extra-cardiac vascular disease following CABG surgery, only partly mediated through increased vein graft failure

March 11, 2013 – Study shows patients with extra-cardiac vascular disease had worse outcomes when undergoing CABG surgery

In a study that examined data from the Project of Ex-vivo Vein Graft ENgineering via Transfection IV (PREVENT IV) trial, researchers found that patients with extra-cardiac vascular disease (ECVD) who underwent coronary artery bypass graft (CABG) surgery had an increased risk of death, myocardial infarction (MI, or heart attack), or revascularization after 5 years. This increased risk was only partly mediated through increased vein graft failure as measured at one year.

The study was conducted by DCRI Fellow Ralf Harskamp, MD, with contributions from John Alexander, MD, MHS; Phillip Schulte, PhD; W. Schuyler Jones, MD; Eric Peterson, MD, MHS; Robert Califf, MD; and Renato Lopes, MD, PhD. An abstract poster summarizing this study’s findings was selected by the ACC.13 and TCT@ACC-i2 Program Committees as the “Best FIT (Fellows in Training) Poster” at this years’ American College of Cardiology Scientific Sessions in San Francisco, CA.

Harskamp explained that PREVENT IV offered an excellent source of data to examine vein graft failure among ECVD patients undergoing CABG, because information was collected per protocol at one year of angiographic follow-up irrespective of symptoms. Typically, vein graft failure data can only be collected from patients that have clinical reasons for coronary angiography (i.e., clinical graft failure), meaning that patients who experience vein graft failure that did not lead to symptoms are not represented. Harskamp points out, however, that because there was no routine angiographic follow-up after one year, it is difficult to determine how late vein graft failure may have affected vein graft failure outcomes.

ECVD, which is found in one-fifth of patients undergoing CABG, generally refers to any vascular disease not related to the coronary circulation and includes peripheral vascular disease and cerebrovascular disease.

“Although our findings suggest that there may be factors other than associated comorbidities that influence long-term outcomes in patients with ECVD after CABG surgery, these results certainly show the need for future studies to see what we can do to enhance outcomes in ECVD patients,” said Harskamp. “Preventing vein graft failure is only one consideration to ensure greater symptom-free survival in these high-risk patients undergoing coronary artery bypass graft surgery that merits closer examination by surgeons and cardiologists.”