Risk of in-hospital death and adverse ischemic events rises when noncardiac surgery is performed less than six weeks after stent implantation, no matter the stent type, according to a study published May 4 in Circulation: Cardiovascular Interventions.
“Noncardiac surgery performed after coronary stent implantation is associated with an increased risk of stent thrombosis, MI and death,” the authors wrote. “The influence of stent type and period of risk still have to be defined.”
Nicholas L.M. Cruden, PhD, of the University of Edinburgh in Edinburgh, U.K., and colleagues evaluated 1,953 patients who received either drug-eluting stents (DES) or bare-metal stents (BMS) and subsequently underwent noncardiac surgery between April 2003 and March 2007.
The researchers used date from the Scottish Coronary Revascularization Register during the study. Of the 1,953 patients who underwent noncardiac surgery, 570 patients (29 percent) received at least one DES while 1,383 patients received a BMS (71 percent).
The mean age of patients who participated in the trial was 64 and patients who received BMS had a greater number of cormorbidites including diabetes mellitus, hypertension and stable angina.
According to the researchers, results showed no significant differences in rates of in-hospital death or ischemic events. These rates for BMS were 13.3 percent compared with 14.6 percent for DES.
However the results showed that 42 percent of patients who underwent noncardiac surgery within six weeks of stent implantation suffered more adverse events compared to 13 percent of patients whose surgery was postponed six weeks after stent procedure.
Additionally the researchers said that patients who underwent noncardiac surgery within one month of stent implantation for acute coronary syndrome had the greatest risk for in-hospital death or adverse cardiac events compared with patients with coronary artery disease, 65 percent versus 32 percent, respectively.
The authors wrote, “On univariate analysis, previous CABG surgery and increasing age, but not stent type, were associated with an increased risk of in-hospital death or ischemic cardiac events.”
Results also showed that between urgent and emergent noncardiac surgery, the rates of in-hospital death and ischemic cardiac events were 12.8 percent versus 16.2 percent, respectively.
"These findings have important implications for a large number of patients," said Cruden. “We believe that our findings support current recommendations that noncardiac surgery should be deferred for at least six weeks after bare-metal stent implantation.”
Additionally the authors said, “Furthermore, our findings would suggest that the increased cardiac risk, although diminishing in magnitude, may extend beyond six weeks, irrespective of the type of stent used.”
The authors concluded that more large scale trials are needed to confirm the results and risks of the relationship between the presence of coronary stents and noncardiac surgery.
The trial was funded by a Health Services research grant from the Chief Scientist Office.