NEJM: Common post-CABG procedure linked to adverse outcomes

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Endoscopic vein-graft harvesting is independently associated with vein-graft failure and adverse clinical outcomes after CABG, according to a study in the July 16 edition of the New England Journal of Medicine.

Vein-graft harvesting with the use of endoscopy (endoscopic harvesting) is a technique that is widely used to reduce postoperative wound complications after CABG, but the long-term effects on the rate of vein-graft failure and on clinical outcomes are unknown, according to lead author Renato D. Lopes, MD, PhD, from the Duke Clinical Research Institute at Duke University Medical Center in Durham, N.C., and colleagues.

Endoscopic harvesting was introduced in 1996 as an alternative open vein-graft harvesting, mainly because the latter is associated with serious complications and discomfort to the patient, the authors wrote. Since that time, endoscopic harvesting has become the predominant mode of graft harvesting at many surgical centers - used in approximately 70 percent of U.S. CABG surgeries, according to the Society of Thoracic Surgery (STS) National Database.

The researchers examined the outcomes in patients who underwent endoscopic harvesting (1,753 patients) as compared with those who underwent graft harvesting under direct vision, termed 'open harvesting' (1,247 patients), in a secondary analysis of 3,000 patients undergoing CABG. They determined a method of graft harvesting by the surgeon; and defined vein-graft failure as stenosis of at least 75 percent of the diameter of the graft on angiography 12 to 18 months after surgery. Data were available in an angiographic subgroup of 1,817 patients and 4,290 grafts.

The investigators defined the clinical outcomes as death, MI and repeat revascularization. They used generalized estimating to adjust for baseline covariates associated with vein-graft failure and to account for the potential correlation between grafts within a patient.

Lopes and colleagues found that the baseline characteristics were similar between patients who underwent endoscopic harvesting and those who underwent open harvesting. Patients who underwent endoscopic harvesting had higher rates of vein-graft failure at 12 to 18 months than patients who underwent open harvesting (46.7 vs. 38 percent).

At three years, the authors reported that endoscopic harvesting was also associated with higher rates of repeat revascularization (20.2 vs. 17.4 percent), death or MI (9.3 vs. 7.6 percent) and death (7.4 vs. 5.8 percent).

The researchers noted that previous studies of endoscopic harvesting had short-term follow-up and were not randomized. Of note, the patients in this trial were not randomized either.

Lopes and colleagues recommended randomized clinical trials to evaluate the safety and effectiveness of this harvesting technique, and suggested the "increased risk of worse outcomes with endoscopic harvesting should be weighed against its known short-term benefits."