Stenting before CABG linked to higher mortality for diabetic patients

Key clinical point: Diabetic triple vessel–disease patients with prior percutaneous coronary intervention stenting (PCI-S) have poorer long-term outcomes after coronary artery bypass grafting than do patients who had no prior PCI-S.

Major finding: After adjusting for preoperative clinical characteristics and other factors, prior PCI-S was associated with 39% increased risk of mortality 5 years after surgery. Further adjustment for date of surgery or operative parameters did not alter the association.

Data source: Single-center review of 7,005 CABG cases performed from 1996 to 2007.

Disclosures: The Johns Hopkins Murex Research Award supported the lead author. The authors had no other relevant disclosures.

View on the News

Gray zone of clinical ambiguity

Because diabetes affects vascular physiology and can lead to multivessel disease, surgical revascularization vs. percutaneous coronary intervention has proved more successful in diabetic patients, Dr. Paul Kurlansky said in his invited commentary. However, “the potential impact of newer generation drug-eluting stents on improving these results remains to be seen,” he wrote (J. Thorac. Cardiovasc. Surg. 2015 [doi:10.1016/j.jtcvs.2015.02.007).

Comparing CABG and PCI in diabetic patients has been challenging for a variety of reasons, including the nuances of clinical judgment and different techniques. “It is in this gray zone of clinical ambiguity that many if not most patients actually reside,” he said, giving credit to Dr. Nauffal and colleagues for trying to address this ambiguity.

Dr. Paul Kurlansky

The study data, however, had many limitations, Dr. Kurlansky said. The authors could not specify indications for stent deployment, disease severity at the time of stenting and the choice of procedure among them. “An equally plausible hypothesis might therefore suggest that the appropriate need for prior stenting identified a subset of patients with more aggressive disease who therefore succumbed at an earlier age,” he said.

CABG that utilizes the internal mammary artery has been linked to enhanced physiologic properties that promote vasodilatation, inhibit thrombosis and atherosclerosis, and support the health of the vascular endothelium, he noted. In the diabetic patient, these properties may enhance the ability of CABG to address not only arterial blockages, but also the underlying physiology of atherosclerosis. “With the rising tide of diabetic vasculopathy, it will become increasingly important to consider both clinical utility and underlying physiology in navigating the uncertain path to optimal patient care,” Dr. Kurlansky wrote.

Dr. Kurlansky is with the department of surgery at Columbia University, New York.




Since the debut of drug-eluting stents, more high-risk patient groups, namely diabetic patients, have undergone coronary stenting as opposed to coronary artery bypass grafting (CABG) as an option to open blocked arteries; however, diabetic patients with stents who go on to have CABG have significantly higher 5-year death rates than do unstented diabetics who undergo CABG, according to a study published in the May issue of the Journal of Thoracic and Cardiovascular Surgery.

A review of 7,005 CABG procedures performed from 1996 to 2007 at Mercy St. Vincent Medical Center in Toledo, Ohio, found that diabetic patients with triple-vessel disease and a prior percutaneous coronary intervention with stenting (PCI-S) who underwent CABG had a 39% greater risk of death within 5 years of the operation. The findings are significant, according to Dr. Victor Nauffal and his colleagues at the American University of Beirut, because increasing numbers of patients with coronary stents are referred for CABG (J. Thorac. Cardiovasc. Surg. 2015 [doi:10.1016/j.jtcvs.2015.01.051).

Previous studies have linked prior stenting to an increased risk of bleeding and stent thrombosis during CABG, so having a better understanding of anticoagulation during the operation and the timing of the surgery after stenting could decrease complications. Investigations of the long-term outcomes of patients with stents who have CABG, however, have been lacking. This study investigated the premise that diabetics with triple-vessel disease and a stent had poorer outcomes because of endothelial dysfunction and the increased strain that triple-vessel disease places on the heart.

After exclusions, the final study population comprised 1,583 diabetic patients with concomitant triple-vessel disease, 202 (12.8%) of whom had coronary stents. The study defined triple-vessel disease as blockages of 50% or more in all three native coronary vessels or left main artery plus right coronary artery disease.

Early mortality rates – death within 30 days of the procedure – were similar between the two groups: 3.3% overall, 3% in the prior-PCI group, and 3.3% in the no-PCI group; therefore, prior PCI was not a predictor of early mortality.

Five-year cumulative survival was 78.5% in the no-PCI group, compared with 74.8% in the PCI group. When adjusting for a variety of clinical variables before CABG, stenting was associated with a 39% greater mortality at 5 years. The investigators accounted for the emergence of drug-eluting stents during the 10-year study period but found that they did not contribute significantly to overall outcomes.

The cause of death was known for 81.7% (282 of 345) of the deaths in the overall cohort, with 5-year cardiac deaths higher in the PCI-S group: 8.4% vs. 7.5% for the no-PCI group. “Notably, 100% of PCI-S cardiac mortality was categorized as coronary heart disease related compared to 89.3% (92/103) of cardiac mortality in the no-PCI group,” Dr. Nauffal and his associates said.

Careful patient selection for CABG is in order for diabetics with triple-vessel disease, particularly those with a prior stent, the authors advised. “An early team-based approach including a cardiologist and cardiac surgeon should be implemented for optimal revascularization strategy selection in diabetics with triple-vessel disease and for close medical follow-up of those higher risk CABG patients with history of intracoronary stents,” Dr. Nauffal and his colleagues concluded.

The Johns Hopkins Murex Research Award supported Dr. Nauffal. The authors had no other relevant disclosures.

Next Article:

   Comments ()