The recent report from the SYNTAX trials should give pause to our interventionalist colleagues embarking on multiple angioplasty and stenting procedures in patients with complex coronary anatomy.
SYNTAX randomized 1,800 patients with left main or triple-vessel coronary artery disease to either percutaneous coronary intervention (PCI) with the TAXUS drug-eluting stent or coronary artery bypass grafting (CABG) after being judged by a heart team as being in equipoise in regard to the appropriateness of either procedure ( Eur Heart J. 2011;32;2125-34 ). The findings of several previous analyses have trended toward benefit for CABG, but none as clearly as SYNTAX. The original study was reported 6 years ago ( Lancet 2013 Feb;381:629-38 ) and indicated that CABG was superior to PCI in patients with complex lesions. The most recent 5-year data of that study ( J Am Coll Cardiol. 2016 Jan:67;42-55 ) indicates that cardiac mortality in the CABG patients is superior to that in the PCI group (5.3% vs. 9.6%, respectively), and the follow-up data provide more in-depth analysis in addition to the mechanism of death. Most importantly, the recent 5-year data clarify the reasons PCI fails to measure up to the results of CABG in patients with complex coronary artery disease.
Although randomized data in regard to the benefit of CABG, compared with medical therapy in this high-risk population, are now available from the STICH 5-year follow-up ( N Engl J Med. 2016 Apr 21;374:1511-20 ), information about the long-term benefit of PCI, compared with medical therapy, does not exist. SYNTAX provides us at least a reference point in regard to the relative benefit of these two interventions. The recent analysis assists the interventional cardiologist and surgeon in making the choice between these two procedures based on anatomy. The joint decision making that has evolved in the last few years in regard to valvular surgery appears to have had an impact on the decision-making process in other cardiosurgical procedures, and particularly coronary artery interventions.
One of the overriding predictors of increased mortality with PCI is the increased complexity of anatomy. The higher SYNTAX score was related to incomplete revascularization using PCI, compared with CABG. The presence of concomitant peripheral and carotid vascular disease, in addition to a left ventricular ejection fraction of less than 30%, favored the CABG group. Multiple stents and stent thrombosis were also issues leading to the increased mortality in the PCI group. The main cause of death was recurrent myocardial infarction, which occurred more frequently in the PCI patients and was associated with incomplete revascularization.
The data in the SYNTAX follow-up is not new, but do reinforce what has been reported in previous meta-analyses. This study does, however, emphasize the importance of recurrent infarction as a cause of death in these patients with complex anatomy. It is possible that new stent technology and coronary flow assessment at the time of intervention could have improved the outcome of this comparison and improved the long-term patency of the stented vessels. PCI is an evolving technology heavily affected by the experience of the operator. CABG surgery has also changed, and its associated mortality and morbidity have also changed and improved. It is clear that this population raises important questions in which the operators need to individualize their decision based on trials like SYNTAX.
Dr. Goldstein, medical editor of Cardiology News, is professor of medicine at Wayne State University and division head emeritus of cardiovascular medicine at Henry Ford Hospital, both in Detroit. He is on data safety monitoring committees for the National Institutes of Health and several pharmaceutical companies.
