COMPREHENSIVE STRATEGY FOR THE EVALUATION AND TRIAGE OF THE CHEST PAIN PATIENT

Study objective: To evaluate the safety and efficacy of a systematic e valuation and triage strategy including immediate resting myocardial p erfusion imaging in patients presenting to the emergency department wi th chest pain of possible ischemic origin. Methods: We conducted an ob servational study of 1,187 consecutive patients seen in the ED of an u rban tertiary care hospital with the chief complaint of chest pain. Wi thin 60 minutes of presentation, each patient was assigned to one of f ive levels on the basis of his or her risk of myocardial infarction (M I) or unstable angina (UA): level 1,MI; level 2, MI/UA; level 3, proba ble UA; level 4, possible UA; and level 5, noncardiac chest pain. In t he lower risk levels (3 and 4), immediate resting myocardial perfusion imaging was used as a risk-stratification tool alone (level 4) or in combination with serial markers (level 3). Results: Acute MI, early re vascularization indicative of acute coronary syndrome, or both were co nsistent with risk designations: level 1:96% MI, 56% revascularization ; level 2: 13% MI, 29% revascularization; level 3: 3% MI, 17% revascul arization; level 4:7% MI; 2.5% revascularization. Sensitivity of immed iate resting myocardial perfusion imaging for MI was 100% (95% confide nce interval [CI], 64% to 100%) and specificity 78% (74% to 82%). In p atients with abnormal imaging findings, risk for MI (7% versus 0%, P < .001; relative risk [RR], 50; 95% CI, 2.8 to 889) and for MI or revasc ularization (32% vs 2%, P <.001; RR, 15.5; 95% CI, 6.4 to 36) were sig nificantly higher than in patients with normal imaging findings. Durin g 1-year follow-up, patients with normal imaging findings (n=338) had an event rate of 3% (revascularization) with no MI or death (combined events: negative predictive value, 97%; 95% CI, 95% to 98%). Patients with abnormal imaging findings (n=100) had a 42% event rate (combined events: RR, 14.2; 95% CI,6.5 to 30; P <.001), with 11% experiencing MI and 8% cardiac. Conclusion: This strategy is a safe, effective method for rapid triage of chest pain patients. Rapid perfusion imaging play s a key role in the risk stratification of low-risk patients, allowing discrimination of unsuspected high risk patients who require prompt a dmission and possible intervention from those who are truly at low ris k.