Study Suggests Optimal Wait Times for Surgery After Stenting

By Peggy Peck
ROCHESTER, Minn., 27 sept 2008-- Elective surgery should be delayed for 90 days following placement of a bare-metal coronary stent and for more than a year when a drug-eluting device is used, researchers here reported. Those findings emerged from a pair of studies, published in the October issue of Anesthesiology, that examined cardiac risks associated with noncardiac elective surgery for patients who had undergone percutaneous coronary interventions using stents. The studies confirmed that surgical risks are greatest when patients are receiving dual antiplatelet therapy (aspirin and clopidogrel [Plavix]), said study co-author Charanjit S. Rihal, M.D., of the Mayo Clinic in Rochester, Minn. Current American College of Cardiology/American Heart Association guidelines suggest one month of dual antiplatelet therapy and a six-week wait before noncardiac surgery following bare-metal stent placement and at least 12 months of clopidogrel and aspirin after a drug-eluting stent is used and before noncardiac surgery.
Data from 899 patients were included in the researchers' analysis of bare-metal stent outcomes. The drug-eluting stent study included outcomes data from 520 patients.
The bare-mental stent patients were treated from Jan. 1, 1990 through Jan. 1, 2005, and the drug-eluting stent patients were treated from April 22, 2003 through Dec. 31, 2006.
In each analysis the researchers examined the risk for complications among patients who underwent non-cardiac surgery following stent placement and calculated temporal relationships between adverse cardiac events associated with the surgery and stent placement.
Among the findings:
There was no significant association between the risk of a major acute coronary event following noncardiac surgery and the timing of drug-eluting stent placement, but the lowest event risk occurred for surgeries performed more than 12 months after stenting.
Among patients who received bare-metal stents, the complication rate was 10.5% for surgeries performed less than 30 days after PCI, 3.8% for surgeries between 31 and 90 days, and 2.8% after 90 days.
Among patients with bare-metal stents, multivariate analysis confirmed that time between stenting and surgery was a significant predictor of cardiac complications of surgery (OR 3.2, 95% CI 1.5 to 6.9, P=0.006)
Univariate analysis found that age, shock at time of PCI, use of dual antiplatelet therapy, and prior history of myocardial infarction were the significant predictors of cardiac complications of noncardiac surgery in patients with drug-eluting stents (all P<0.05), but the single greatest predictor was emergent surgery (P=0.006)
In an editorial that accompanied the papers, Charles W. Hogue, Jr., M.D. and Jeffrey J. Rade, M.D., of Johns Hopkins Medical Institutions, said the studies "add to a growing body of literature demonstrating that timing really is everything when considering the risks and management of strategy of noncardiac surgery in patients with coronary stents."
Drs. Hogue and Rade wrote that it was also reassuring that the data confirm "the current guidelines, which recommend delaying elective noncardiac surgery for at least six weeks after BMS implantations and one year after DES implantation, but caution that some risk does extend beyond those time frames."
Dr. Rihal and colleagues noted that their studies, while reassuring, were limited by their retrospective design and by the failure to capture data such as beta-blocker and statin use.
Another limitation noted by the authors and the editorialists was the lack of a control group who underwent coronary angiography, had documented coronary artery disease that was not treated with PCI or CABG, and then went on to have noncardiac surgery.
The studies were institutionally funded.
Dr. Rihal reported no financial disclosures.
Drs. Hogue and Rade reported funding from the National Institutes of Health and the American Heart Association. Dr. Rade also reported funding from BMS/Sanofi.
Primary source: AnesthesiologySource reference:Nuttall GA, et al "Time and Cardiac Risk of Surgery after Bare-metal Stent Percutaneous Coronary Intervention" Anesthesiology 2008; 109: 588-95. Additional source: AnesthesiologySource reference: Rabbitts JA, et al "Cardiac Risk of Noncardiac Surgery after Percutaneous Coronary Intervention with Drug-eluting Stents" Anesthesiology 2008; 109: 596-604. Additional source: AnesthesiologySource reference: Rade JJ, Hogue CW Jr "Noncardiac surgery for patients with coronary artery stents: Timing is everything" Anesthesiology 2008 109: 573-5.