Risk of major adverse cardiac events following noncardiac surgery in patients with coronary stents.

Hawn MT, Graham LA, Richman JS et al.
JAMA. 2013 Oct 9;310(14):1462-72. doi: 10.1001/jama.2013.278787

Background

Because noncardiac surgery soon after coronary stent placement is associated with an increased risk of adverse cardiac events, it is desirable to delay elective surgery as long as possible after stent placement.
Guidelines issued by the American Heart Association (AHA)/American College of Cardiology (ACC) in 2007 have been revised after observations of unanticipated late stent thrombosis after cessation of dual antiplatelet therapy (APT) and case reports of stent thrombosis in patients with drug-eluting stents (DES) undergoing noncardiac surgery. The new guidelines recommend continuing dual APT for all patients at least 1 year after DES implantation [1]. If delaying surgery is not possible, it should be performed without cessation of APT.
However, the recommended delays are based on limited and conflicting evidence. Larger, multicenter cohort studies did not confirm the higher rates of major adverse cardiac events (MACE) seen in initial case series after DES implementation, as compared to bare metal stents (BMS) [2-4]. This study aimed to better understand the relationship between stent type, APT, and MACE associated with noncardiac surgery after coronary stent placement. A national cohort of Veterans Affairs (VA) patients who had either coronary DES or BMS placed were evaluated.

Main results

• In a model assessing the relative contribution of factors to MACE, nonelective presentation for the surgical hospitalisation, conditions associated with ischemic cardiac disease and higher revised cardiac risk index (rCRI) score were significantly associated with MACE. Stent type  was not associated with MACE, neither was there an interaction between stent type and time to surgery.
• MACE was correlated to time from stent to surgery, with higher MACE rates seen for surgery closer to stent implantation.  After adjustment, the odds of MACE for surgery between 6 weeks and 6 months after DES placement was lower than after BMS placement (adjusted OR (AOR): 0.75, 95%CI: 0.62-0.91). The odds were not different for surgery less than 6 weeks after stent implantation (AOR: 1.1, 95%CI: 0.8-1.5) or more than 6 months after stent placement (AOR: 0.92, 95%CI: 0.82-1.05).
• No significant difference was observed in the likelihood of receiving dual APT prior to surgery (59.5% cases vs. 55.6% controls, P=0.43) or complete discontinuation of APT for at least 5 days (22.9% cases vs. 25.4% controls, P=0.49).  There was no association between complete APT cessation and MACE (OR: 0.86, 95%CI: 0.57-1.29).

Conclusion

This study shows that the acuteness of clinical presentation for surgery and several markers of advanced cardiac disease is important for the development of MACE after noncardiac surgery in patients who recently had coronary stent implantation. Time from stent placement to surgery was associated with MACE, although only significantly in the first 6 months after the stent procedure. APT cessation was not associated with MACE.
Although future prospective studies should confirm the safety of noncardiac surgery at 6 months after DES implantation, these findings challenge the current focus on stent type and timing of surgery when assessing perioperative risk in patients with coronary stents. Additional cardiac risk factors appear more relevant in risk stratification in patients with stents.
Guidelines that recommend prolonged delay and continued APT for patients with DES need to be reconsidered.

References

1. Grines CL, Bonow RO, Casey DE Jr, et al; American Heart Association; American College of Cardiology; Society for Cardiovascular Angiography and Interventions; American College of Surgeons; American Dental Association; American College of Physicians. Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents. Circulation. 2007;115(6):813-818.
2. Berger PB, Kleiman NS, Pencina MJ, et al; EVENT Investigators. Frequency of major
noncardiac surgery and subsequent adverse events in the year after drug-eluting stent placement results from the EVENT (Evaluation of Drug-Eluting Stents and Ischemic Events) Registry. JACC
Cardiovasc Interv. 2010;3(9):920-927.
3. Wijeysundera DN, Wijeysundera HC, Yun L, et al. Risk of elective major noncardiac surgery after coronary stent insertion: a population-based study. Circulation. 2012;126(11):1355-1362.
4. Rabbitts JA, Nuttall GA, Brown MJ, et al. Cardiac risk of noncardiac surgery after percutaneous coronary intervention with drug-eluting stents. Anesthesiology. 2008;109(4):596-604.

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