CHICAGO — In the hands of experts, there was no difference in rates of major adverse cardiac events with endoscopic vs open vein-graft harvesting nearly 3 years after on-pump coronary artery bypass surgery (CABG) in the Randomized Endo-Vein Graft Prospective (REGROUP) trial.
The primary end point of death, myocardial infarction (MI), or revascularization occurred in 13.9% of patients with endoscopic vein harvesting (EVH) and in 15.5% of patients with open vein harvesting (OVH) at a median follow-up of 2.78 years (hazard ratio [HR], 1.12; 95% confidence interval [CI], 0.83 - 1.51; P = .47).
Rates were lower with EVH for the individual components of death (6.4% vs 8%), MI (4.7% vs 5.9%), and revascularization (5.4% vs 6.1%). As expected, patients also experienced fewer harvest site complications.
"Endoscopic harvest performed by an expert may be considered the preferred vein harvesting modality," Marco Zenati, MD, Veterans Affairs Boston Healthcare System and Harvard Medical School, said here at the American Heart Association (AHA) Scientific Sessions 2018.
Although the use of arterial conduits has steadily increased, saphenous vein grafts are used in as many as 90% of CABG in North America. Decreased patency and a higher death rate in the observational PREVENT IV trial, however, raised safety concerns about the EVH technique.
"Is this the last trial? Is the question fully answered? My personal take on this is that I think it is," said Marc Ruel, MD, MPH, University of Ottawa Heart Institute, Ontario, Canada, who was invited to discuss the study, which was published simultaneously in the New England Journal of Medicine.
REGROUP showed that EVH is as good as OVH for the prevention of MACE. Moreover, the study had few sources of bias and a commendably high randomized to screening ratio of more than 1 to 3, he said.
Still, Ruel noted that it is not clear that these were OVH expert centers, given a slightly longer harvest time, and there was no use of pedicled no-touch OVH, a technique in which the saphenous vein is harvested with a layer of fat around it. The technique seems to be associated with better histologic and clinical outcomes.
Moreover, the study lacked histologic and patency data. "Patency is assumed to be good in this trial, but it's not impossible that it could be low across the board," said Ruel, who pointed out similarities between the REGROUP mortality rate and the 4-year mortality rate in the EXCEL trial.
During the discussion, Zenati said they agonized over the issue of graft patency during the planning phase but were swayed by the experience of several trials, including ROOBY, in which fewer than 60% of patients returned for angiography at 1 year.
"The fact that angiography is less than an ideal surrogate for clinical events made us make a decision to just go with hard outcomes," he said. "It is a limitation."
Session comoderator Roxana Mehran, MD, Ichan School of Medicine at Mount Sinai, New York City, remarked, "It would have been great to have patency, given that now we can do CT angiography in a very noninvasive way and figure out patency."
In light of the mortality rate and the fact that only 1100 patients underwent randomization, she added, "How confident are you that you actually have met the noninferiority?"
Zenati replied, "We actually were powered to determine the difference; and I also want to say these patients had a compliance that was approaching 90% at 2 years with triple guideline-directed medical therapy. So we are confident."
This prompted session comoderator Timothy Gardner, University of Pennsylvania, Philadelphia, to comment, "I think this study takes the cloud away from the endoscopic vein harvest that the PREVENT trial had cast."
EVH is known to have a steep learning curve, and one of the criticisms of PREVENT IV is that it allowed less experienced endoscopic vein-graft harvesters to participate. As a result, REGROUP required EVH harvesting expertise, defined as having performed an excess of 100 EVH procedures with less than a 5% rate of conversion to open surgery within an EVH program that had been established for more than 2 years.
A total of 1150 patients at 16 VA cardiac surgery centers were randomly assigned to EVH or OVH. Their mean age was 66 years, the mean Society of Thoracic Surgery PROM score was 0.94%, and the mean SYNTAX score was 28.5.
The cohort received an average of 3.1 grafts, with a bypass time of 108.4 minutes. Urgent CABG was performed in 27% of patients, and EVH was converted to OVH in 5.6%.
Harvest site complications such as leg wound infections, hospital stay exceeding 14 days for wound healing, and the number of patients who required antibiotics at 6 weeks' follow-up were all lower with EVH than OVH. The EVH group was significantly more likely to report no impact of incisional leg pain on function (79.1% vs 62.2%; P < .05).
There was also a trend for fewer recurrent major cardiac events with the endoscopic approach (HR, 1.29; 95% CI, 1.00 - 1.68), Zenati said.
In addition to the lack of graft patency imaging, he said other limitations were the predominantly male population, exclusion of off-pump CABG, and participation of only expert harvesters.
In an AHA media briefing on the study, Zenati said they defined EVH expertise arbitrarily on the basis of literature and common sense but that going forward, it will be important to establish specific expert criteria.
"It will also be important to have a specific CPT code, because now there isn't a specific CPT code for endoscopic harvesting, and that would help," he said. "Also, hospitals set their expertise thresholds for performance."
Commenting for theheart.org | Medscape Cardiology, Jennifer S. Lawton, MD, chief of cardiac surgery at Johns Hopkins Hospital, Baltimore, Maryland, said, "This is a very important and very relevant trial" but that "nothing is definitive yet."
She noted that there are many factors that go into vein graft patency and MACE and that these were VA patients, so the patients in the cohort were mostly male, were relatively healthy, and were at low risk for adverse events.
"We need longer-term follow-up in more patients and in a more diverse population," Lawton said.
Nevertheless, "The patients love the endoscopic harvesting," she said. "It is particularly beneficial in patients that are obese and have large legs, and the risk of infection is lower; we know that from many studies."
Yet when asked what she would prefer if facing CABG, Lawton responded without hesitation, "What I would want personally is all arterial grafting, because I believe the data that arterial grafts prolong survival. Arteries and veins are just so different, and we know that 50% to 60% of vein grafts are patent at 10 years, but for arterial grafts, it's much higher, in the 90s."
Donald Lloyd-Jones, MD, Northwestern University, Chicago, said in an interview that almost all patients are going to require more than one conduit and that unfortunately, in most cases today, the left internal mammary artery is still used.
"So we're still going to be harvesting a lot of vein grafts, and my patients in the past who had the full zipper on their leg had a tough time ambulating, worse outcomes, more infections, and more complications," he said. "So this endoscopic approach for the foreseeable future is very much here to stay and very much better than the full open approach."
The study was supported by the Department of Veterans Affairs. Dr Zenati and Dr Lawton report have disclosed no relevant financial relationships.
N Engl J Med. Published online November 11, 2018. Full text
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Cite this: REGROUP Lifts Cloud Over Endoscopic Vein Harvesting for CABG - Medscape - Nov 12, 2018.