Indications for Coronary Angiography

The indications for performing coronary angiography as part of a preoperative assessment are essentially identical to those used to justify coronary angiography in the nonoperative setting. Typical indications include the following: 1. Noninvasive test results suggesting a high risk of adverse outcomes, such as the presence of extensive (multivessel distribution) myocardial ischemia. For example, among a subgroup of patients with abnormal dobutamine stress echocardiography results before noncardiac surgery, the rate of perioperative cardiac events was found to be still relatively low (2.8%) in patients with a more limited extent of ischemia (1-4 segments) but much higher (36%) in those with more extensive ischemia (>5 segments), despite the use of P-blocker therapy.10

2. An equivocal noninvasive test result in a patient with multiple clinical risk factors facing high-risk surgery

3. The presence of exertional angina not responsive to appropriate medical therapy, especially if the patient is facing a moderate- or high-risk surgical procedure

4. The presence of unstable angina

It is important to emphasize that, given the current absence of prospective data indicating that surgical risk can be favorably influenced by preoperative coronary revascularization, the concept that PCI or coronary artery bypass grafting (CABG) should be undertaken to "get the patient through" a subsequent noncardiac surgery is not supported by evidence-based standards, and these interventions should be used sparingly for this indication. Consequently, the ACC/AHA consensus guidelines assert that preoperative coronary revascularization is most likely "appropriate for only a small subset of patients at very high risk." Despite the published guidelines, a substantial amount of physician-to-physician variability exists in clinical practice regarding the role of preoperative coronary revascularization. In one study, 31 physicians were presented with the clinical scenarios and angiographic findings of 12 patients scheduled for vascular surgery and asked to make recommendations with respect to the appropriateness of coronary revascularization. The physicians' recommendations deviated from published guidelines in 40% of cases, and the likelihood of discordance between two cardiologists was 54%.11

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