YES
I believe on-pump coronary artery bypass graft (CABG) surgery should be our primary operation, with off-pump CABG reserved only for certain situations.
In talking about these two surgical options, there are basically three main issues of interest: procedural outcomes, the quality of revascularization, and long-term effectiveness.
Dr. Joseph F. Sabik
Procedural outcomes: In the 1990s, there was great excitement for the potential for off-pump CABG. We thought survival would be better, stroke less common, neurocognitive outcomes improved, etc., but after several randomized studies and a number of well-controlled observational studies, we found that, in terms of the important procedural outcomes – death, MI, stroke, and acute renal failure – there were actually no differences between off- and on-pump CABG. We saw this in ROOBY, with low-risk patients and less experienced surgeons; in the Canadian CORONARY trial, with experienced off-pump surgeons; and in the European GOPCABE trial, where the surgeons were very experienced and the patients were high risk.
There are some benefits with off-pump CABG in terms of what I call the "reversible" complications of surgery: fewer transfusions, less postoperative atrial fibrillation, fewer respiratory infections; but I believe these things have to be balanced against some of the negative effects of off-pump surgery in terms of its quality of revascularization and long-term effectiveness.
Probably one of the biggest disappointments we’ve had with off-pump CABG is that, in the trials, we didn’t see any major difference in neurocognitive dysfunction. What we learned is that cardiopulmonary bypass really is not that bad in terms of neurocognitive dysfunction after surgery.
One issue that tends to be forgotten is the risk associated with conversion. In a hemodynamically unstable patient, converting from off-pump to on-pump is associated with higher risks of death, bleeding, renal failure, stroke, respiratory failure, and GI complications. In CORONARY, with experienced surgeons, the conversion rate was almost 7.9%, and in GOPCABE, it was 9.7%. Even with experienced surgeons, conversions do occur, and they have negative consequences.
Quality of revascularization: We know that long-term survival is related to completeness of revascularization. The more ischemic myocardium that is left at risk after CABG, the more likely the patients is to have an MI or die, and this has been very clearly demonstrated in the surgical literature as well as the percutaneous coronary intervention literature. It has been shown multiple times that fewer grafts are done in off-pump patients, compared with on-pump patients. Indeed, in a recent Cochrane meta-analysis of more than 7,000 patients in 57 trials, there were significantly more grafts done in on-pump than off-pump cases.
Also in terms of graft patency, again, multiple studies have shown lower graft patency in off-pump patients, either directly or by means of showing a higher reintervention rate after off-pump as compared with on-pump surgery. In both CORONARY and GOPCABE, the repeat revascularization rate at 30 days was higher for off-pump CABG.
Long-term effectiveness: The long-term results from ROOBY are very sobering: significantly higher 1-year cardiac mortality in the off-pump arm and higher 1-year composite adverse events. Again, in the 2012 Cochrane meta-analysis, with more than 10,000 patients in 75 trials, mortality was significantly higher with off-pump patients, compared with on-pump, with a hazard ratio of 1.24 (95% CI, 1.01-1.53). When the authors of the Cochrane meta-analysis removed what they called the "studies with bias," this signal was even stronger. Also in observational studies, such as one published by Racz et al. in 2004 (J. Am. Coll. Cardiol. 2004; 43: 557-64), the best survival was found to be in patients who had on-pump CABG and the worst in those who had undergone off-pump CABG.
In summary, procedural outcomes with off-pump and on-pump CABG are similar, albeit with lower reversible complications in the off-pump patients, but a greater conversion risk, along with its associated complications. The quality of the revascularization is worse in off-pump patients, the completeness of revascularization is less and re-intervention rates are higher, and the bottom line, of course, it that there is higher long-term mortality after off-pump CABG.
"Should off-pump CABG be abandoned?" As our default procedure, yes. The vast majority of our patients are best served with on-pump revascularization.
Dr. Joseph Sabik is the chairman of the department of thoracic and cardiovascular surgery and the Sheik Hamdam Bin Rashid Al Maktoum Distinguished Chair at the Cleveland Clinic. He disclosed that he performs both off-pump and on-pump CABG.
References
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