Study: Stenting diabetics pre-CABG does not increase risk

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Performing stenting prior to CABG surgery in diabetics does not increase the risk for perioperative risk for mortality or morbidity after CABG, according to a study published in this month's Journal of Thoracic Cardiovascular Surgery.

“A negative relationship between coronary stenting before coronary artery bypass graft (CABG) surgery and the perioperative mortality and morbidity has been shown in diabetic patients,” Andreas Boening, MD, PhD, of the department of cardiovascular surgery at the University of Giessen in Giessen, Germany, and colleagues wrote.

Boening and colleagues used German Health Quality System data and obtained information on 3,311 patients undergoing isolated CABG during 2005 and 2006. Of the 3,311 patients, 1,125 were diagnosed with diabetes mellitus. Patients were classified by the actual treatment strategy they underwent.

Patients within the stent group were younger (ages 68 vs. 70) and had a higher rate of reoperations (13 percent vs. 3.3 percent).

During the study, patients were classified into four groups: no treatment (0 percent of stent group, 0.5 percent of the non-stent group); diet (10.8 percent of the stent group, 13.7 percent of the non-stent group); oral drug therapy (47.6 percent of the stent group, 44.7 percent of the non-stent group); and insulin therapy (41.6 percent of the stent group, 41.1 percent of the non-stent group).

Of the 1,125 patients, 1,092 patients were included in the final analysis; 185 of these patients were stented. The researchers reported that the median time between last stenting procedure and surgery was 82.5 days. Of the stents, 71.5 percent were bare metal stents (BMS) and 16.5 percent were drug-eluting stents (DES). Twelve percent of patients had a combination of both BMS and DES.

Within the stent group, the numbers of interventions with stent implantation were, for one PCI, 72.6 percent; two PCIs, 20.6 percent; three PCIs, 5.5 percent; and more than four PCIs,1.4 percent.

Boening et al reported that indications for CABG surgery were de novo stenoses in 40.9 percent of patients and in-stent restenoses alone or combined with de novo stenoses in 59.1 percent of patients.

Thirty-day mortality rates were 3.86 percent in the non-stent group and 1.62 percent in the stent group. Additionally, postoperative major adverse cardiovascular and cerebrovascular event (MACCE) rates were 12.2 percent in the non-stent group and 5.9 percent in the stent group and occurred more often in diabetic patients without coronary stents.

Patients who did not undergo stenting had a significantly higher cerebrovascular event rate compared with those who underwent stenting, 4.41 percent vs. 1.08 percent, respectively.

“In our dataset, we found no evidence that single or multiple stenting before surgery increases the surgical risk in patients with coronary artery disease who have diabetes,” Boening and colleagues wrote. “The main endpoints of our study, 30-day mortality and MACCE rate, are different between patients having a stent before surgery or not. However, in contrast to the mentioned previous studies, these differences were in favor of stenting before surgery.”

The researchers suggest that one reason stented patients fare better for CABG surgery may be due to the fact that these patients are usually treated with platelet inhibitors and do not stop these types of drug therapy prior to surgery.

“In the light of contradictory results of other studies, the current practice of stenting a coronary artery first and sending the patient to surgery if stenting fails has to be questioned,” the researchers concluded.