Higher Mortality With Off-Pump CABG in Left Main Disease

Debra L Beck

August 08, 2019

Patients with left main disease who underwent off-pump coronary artery bypass grafting (CABG) had an almost twofold risk for death at 3 years compared with those who had on-pump surgery, a post hoc analysis of the EXCEL trial shows.

At 3 years, and after adjustment for baseline differences, all-cause mortality was seen in 8.8% of those who underwent off-pump CABG, compared with 4.5% for on-pump CABG (hazard ratio, 1.94; P = .02).

Also, those who underwent off-pump surgery were less likely to have complete revascularization, with a lower rate of revascularization of the left circumflex artery (84.1% vs 90.0%; P = .01) and the right coronary artery (31.1% vs 40.6%; P = .007), despite having a similar extent of disease.

"The technical challenges of off-pump surgery may result in incomplete revascularization and suboptimal graft quality, which may have a greater adverse impact on patients with extensive myocardium at risk," Umberto Benedetto, MD, PhD, University of Bristol, United Kingdom, and colleagues report in the August 13 issue of the Journal of the American College of Cardiology.

Of the 923 patients who underwent CABG in EXCEL, 271, or 29.4%, had an off-pump procedure, with the choice made according to the surgeon's discretion. The two groups were comparable for most baseline characteristics and pretreatment variables, including the prevalence of bifurcation lesions, number of diseased arteries, involvement of non-left main vessels, and SYNTAX score.

No significant difference was seen in the occurrence of the composite end point of death, myocardial infarction, and stroke (11.8% for off-pump and 9.2% for on-pump; P = .28).

Off-pump CABG rates are falling. The technique currently accounts for less than 15% of all procedures, down from a high of 23% in 2002.

An "Eye Opener"

Discussing these new findings with theheart.org | Medscape Cardiology, Cleveland Clinic cardiac surgeon Faisal G. Bakaeen, MD, said the dramatic difference in mortality was an "eye opener" and yet another sign that off-pump CABG should likely only be performed by experienced operators and for a small number of indications.

"It's well documented that off-pump CABG is associated with incomplete revascularization and suboptimal graft patency, but what this study may be telling us — and this is novel — is that in patients with left main disease, the consequences of incomplete revascularization and suboptimal grafts are dramatic," he explained.

"So, it may be that in this subgroup of patients — and about 25% to 30% of CABG populations have left main disease — you need to think twice before offering the off-pump procedure because if you mess it up, you're going to see a difference in mortality."

Bakaeen coauthored a linked editorial on this EXCEL analysis with Lars G. Svensson, MD, PhD, also from the Cleveland Clinic.

Bakaeen said he used to do almost 25% of his CABG procedures off-pump, but now employs the strategy in less than 5% of cases, reserving it for patients with comorbidities for whom it seems most prudent to avoid the heart–lung machine.

"One emerging trend for me is to do an off-pump LIMA to LAD bypass and then allow the interventional cardiologists to stent vessels in other territories, in what we call a hybrid procedure."

Although off-pump CABG is quickly becoming a "boutique procedure," said Bakaeen, it should not be abandoned. There are several places where off-pump remains more popular, including India, Japan, and countries with the lowest socioeconomic performance, where off-pump is a more economical choice.

"But in North America, Canada, and the US, it is used infrequently at this point and that is not inappropriate."

EXCEL was a randomized noninferiority comparison of percutaneous coronary intervention (PCI) in which everolimus-eluting stents were compared with CABG in patients with left main disease. Three-year clinical follow-up, presented at TCT 2016, showed similar rates of the composite primary end point of all-cause death, stroke, and myocardial infarction between PCI and bypass surgery.

Quality-of-life outcomes, presented at TCT 2017, showed that, although PCI carried a higher risk for repeat revascularization, patients scored similarly on measures assessing angina, dyspnea, and general health concerns, like pain, mobility, and depression.

Benedetto was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol . Bakaeen reported no relationships relevant to this paper to disclose.

J Am Coll Cardiol. 2019;73:2676-2688. Abstract, Editorial

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