CABG Grafts: The Debate Beats On

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minimallyInvasiveCABG_1328892700.jpg - CABG Surgery
Postoperative incision after MIDCAB.
Source: J Am Coll Cardiol Intv, 2008; 1:459-468

For surgeons, understanding what approach is best during CABG surgery has created much debate. A large body of research has cropped up regarding vein harvesting, including a five-year study that showed endoscopic vein harvesting during CABG did not decrease survival or increase harm. Additionally, other data have suggested that using radial arteries during CABG could reduce graft occlusions and decrease the risk of vein disease when compared with saphenous vein grafts. Here are varied opinions on which strategies reduce complications.

Endo argument still open

Minimally invasive surgical approaches typically result in better patient satisfaction, cosmetic improvements and faster healing. Currently, using the endoscopic vein harvesting (EVH) approach during CABG has become routine; however, it is unclear whether this approach is optimal.

Despite the fact that saphenous vein harvesting often is used during CABG, data have linked the procedure to more total wound complications and incision pain, a prolonged recovery period and worse cosmetic results. EVH has been introduced as an approach to thwart these types of complications.

But, despite its benefits, utilization rates in the U.S. are sluggish. Some have blamed this on cost considerations, the technical difficulty of the procedure and its possible link to vein damage.

A study by Lopes et al linked EVH to vein graft failure and adverse outcomes post-CABG procedure (N Engl J Med 2009;361:235-244). In the study, 1,754 patients underwent EVH and 1,247 patients underwent open vein harvesting. Lopes et al reported higher rates of vein graft failure at 12 to 18 months in the EVH arm compared with the open vein harvesting arm, 46.7 percent vs. 38 percent, respectively. At the three-year follow-up, the endoscopic approach was linked to higher rates of death, MI or repeat revascularization.

But a recent study conducted by Niv Ad, MD, chief of cardiac surgery and director of cardiac surgery research at the Inova Heart and Vascular Institute in Falls Church, Va., and colleagues challenged these results when they found that open vein harvesting was linked to higher rates of adverse outcomes. Of the 1,988 study enrollees, 1,734 patients underwent CABG with EVH and 254 underwent CABG with open repair (J Cardiovasc Surg 2011;52[5]:739-748).

"We found no clinical complications during the study, including any alarming graft occlusions," Ad says. Major adverse outcomes occurred in 17.8 percent of patients in the EVH group and 25.2 percent of those in the open harvesting group.

"Endoscopic vein harvesting is better for healing and recuperation and also can decrease wound-site infections," Ad says. "We now think this is the approach to take because we have seen improvement at one end and no harm on the other."

Last year, Donald S. Likosky, PhD, associate director of cardiac surgery of the Northern New England Cardiovascular Disease Study Group in Lebanon, N.H., and colleagues from Dartmouth-Hitchcock Medical Center, looked at the trends of EVH across northern New England between 2001 and 2004. Of the 8,542 patients who underwent a CABG procedure, EVH was used 52.5 percent of the time.

"We found that the utilization of the endoscopic approach increased from 2001 to 2004 with about one-third of physicians using the endoscopic approach in 2001 and three quarters of physicians using the approach in 2004," Likosky says. However, registry data linked EVH to an increased risk of bleeding and revascularization (Circulation 2011;123[2]:147-153).

"Despite these concerns, endoscopic vein harvesting is now the preferred approach across medical centers today," Likosky says.

But for some, cost concerns remain a barrier. EVH may reduce infection and length of stay. Yet, Ad says that the cost per case may increase due to higher operating room costs.

Mixed reviews on radial artery grafting

At ACC.11, Fremes et al from Sunnybrook Health Sciences Centre in Toronto, found that radial artery (RA) use during CABG lowered the rates of complete graft occlusions and stenosis when compared with saphenous vein grafts. Five-year data trends showed that fewer RAs became partially occluded when compared with saphenous vein grafts, 12 percent vs. 18.8 percent, respectively. Complete occlusions occurred in 8.9 percent of RAs compared with 17.8 percent of saphenous veins.

However, Goldman and colleagues refuted this evidence, noting that surgeons may need to reconsider using RA grafts. Compared with saphenous