26 Dec Noncardiac Surgery Carries Increased Risk After Cardiac Stent Placement
MedicalResearch.com Interview with:
Dr. Mary T. Hawn MD, MPH
Center for Surgical, Medical Acute Care Research, and Transitions,
Birmingham Veterans Affairs Medical Center
Section of Gastrointestinal Surgery, Department of Surgery,
University of Alabama at Birmingham, Birmingham, Alabama
Medical Research: What is the background for this study? What are the main findings?
Dr. Hawn: Cardiac risk factors and surgical risk factors contribute to the development of postoperative adverse cardiac events, but the relative contribution of each has not been quantified. In this study, we sought to determine the incremental risk of surgery following coronary stent placement on adverse cardiac events. To answer this question we used a retrospective cohort study of VA patients with coronary stents placed during 2000-2010 undergoing non-cardiac surgery within two years of stent placement matched to patients with coronary stents not undergoing surgery. The patients were matched on stent type (drug-eluting versus bare metal) and cardiac risk factors at the time of stent placement. Our outcome of interest was a composite variable of myocardial infarction and coronary revascularization occurring within 30 days of surgery. We calculated adjusted risk differences over time from stent placement using generalized estimating equations.
When comparing the two cohorts, we found a higher rate of composite cardiac events in the surgical cohort compared to the cohort not undergoing surgery. The main findings in the study were that the incremental risk of surgery was greatest when the surgery occurred in the first 6 weeks following stent placement and decreased to approximately 1% after 6 months, where it remained stable out to 24 months. Surgical characteristics associated with a significant reduction in the incremental risk after 6 months following stent placement included elective, inpatient procedures, and in the setting of a drug eluting stent.
Medical Research: What should clinicians and patients take away from your report?
Dr. Hawn: The incremental risk of noncardiac surgery on adverse cardiac events in patients with coronary stents is related to timing of surgery following stent with the highest risk early post-stent placement and stabilizes at approximately 1%, 6 months after stenting. Elective major inpatient procedures especially in patients with drug-eluting stents were associated with significant reductions in the incremental risk when performed more than 6 months following coronary stent. Accordingly, these surgeries may benefit most from delay beyond 6 months.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Hawn: There is still debate over the optimal time to delay non-cardiac surgery after coronary stent placement to mitigate the associated risk. The American College of Cardiology and the American Heart Association guidelines state that elective surgery should be delayed at least 1 month following a bare metal stent and for 12 months following a drug eluting stent. Our current study and the work of others would suggest that the risk is highest in the first 6 months of stent placement, regardless of stent type, and does not significantly change thereafter. Thus, determining the incremental risk associated with a coronary stent and of other specific cardiac risk factors like ischemic heart disease in those undergoing surgery would provide a more complete picture to further guide clinicians in this important decision-making process.
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Last Updated on December 26, 2014 by Marie Benz MD FAAD