What are the implications for anesthetic management when coronary revascularization is performed before noncardiac surgery?
The ACC/AHA Guidelines for Perioperative Cardio-vascular Evaluation for Noncardiac Surgery provide a stepwise algorithm for the preoperative assessment of the patient with an increased risk for PCE. According to these recommendations, patients with coronary revasculariza-tion within the last 5 years without significant change in symptoms or a favorable cardiac evaluation within the last 2 years may proceed for surgery without further testing. An increasing number of patients are presenting for non-cardiac surgery with prior percutaneous coronary artery stenting (new drug-eluting stents have recently been intro-duced), and more patients are taking a combination of anticoagulant and antiplatelet medications, all of which may influence anesthetic management.
Recent data on coronary artery interventional therapy shows an increased incidence of PCE in patients with prior percutaneous coronary myocardial revascularization. A retrospective study by Posner et al. (1999) looked for adverse cardiac outcomes after noncardiac surgery among 686 patients with prior percutaneous transluminal coronary angioplasty (PTCA). Patients with prior PTCA had twice the rate of adverse cardiac outcomes compared with normal subjects, 7 times the rate of angina, almost 4 times the rate of MI, and twice the rate of CHF. Patients who underwent PTCA within 90 days of noncardiac surgery had twice the rate of perioperative MI compared with patients with uncorrected CAD. Kaluza et al. (2000) found a high number of MIs, major bleeding episodes, and fatal events in patients who underwent coronary stent placement less than 2 weeks before noncardiac surgery. Wilson et al. (2003) reviewed a larger cohort at the Mayo Clinic and found that the period of increased risk extended to 6 weeks following stent placement. It is unclear at present, but drug-eluting stents may extend the period of risk even longer by virtue of their inhibition of neointimal formation.
Antiplatelet drugs that prevent thrombosis of the newly stented coronary arteries, such as GPIIb/IIIa receptor antagonists and ADP inhibitors, have profound anticoagu-lative properties, and recommendations about when these drugs should be discontinued prior to neuraxial anesthesia have been created and periodically updated by the American Society of Regional Anesthesia and Pain Medicine (http://www.asra.com). In emergency procedures, these patients demonstrate increased risk of perioperative bleeding and platelet transfusions may be necessary to achieve hemo-stasis. When these antiplatelet regimens are discontinued for elective surgery shortly after coronary interventions, the risk of stent thrombosis is probably increased, especially in the setting of the hypercoagulable state that frequently is present in the postoperative period.
In summary, recently published data suggest an increased risk for patients presenting for noncardiac surgery who have undergone percutaneous coronary interventions with stent placement within the 2 months prior to surgery. While the data are preliminary, elective surgery should be undertaken with caution and attention should be paid to the management of anticoagulation in the perioperative period.