James L. Tatum

Value of acute rest sestamibi perfusion imaging for evaluation of patients admitted to the emergency department with chest pain.

OBJECTIVES This study sought to determine the ability of early perfusion imaging using technetium-99m sestamibi to predict adverse cardiac outcomes in patients who present to the emergency department with possible cardiac ischemia and nondiagnostic electrocardiograms (ECGs). BACKGROUND Evaluation of patients presenting to the emergency department with possible acute coronary syndromes and nondiagnostic ECGs is problematic. Accurate risk stratification is necessary to prevent serious adverse outcomes. Initial results suggest that early perfusion imaging using technetium-99m sestamibi enables reliable risk stratification. METHODS Patients presenting to the emergency department with a low to moderate probability of acute coronary syndromes underwent rapid sestamibi injection with gated single-photon emission computed tomographic imaging. Studies showing perfusion defects with associated wall motion abnormalities were considered positive. RESULTS A total of 532 consecutive patients underwent serial myocardial marker analysis and rest perfusion imaging. Of these patients, perfusion imaging was positive in 171 (32%). Positive perfusion imaging was the only multivariate predictor of myocardial infarction (MI) (p < 0.0001, odds ratio [OR] 33, 95% confidence interval [CI] 7.7 to 141) and was the most important independent predictor of MI or revascularization (p < 0.0001, OR 14, 95% CI 7.3 to 25), followed by diabetes (p < 0.01, OR 2.8, 95% CI 1.5 to 5.1), typical angina (p = 0.01, OR 2.1, 95% CI 1.2 to 3.7) and male gender (p = 0.03, OR 1.9, 95% CI 1.1 to 3.5). The sensitivity of positive perfusion imaging for MI was 93% (95% CI 77% to 98%), and for MI or revascularization it was 81% (95% CI 71% to 88%), with negative predictive values of 99% (95% CI 98% to 100%) and 95% (95% CI 92% to 97%), respectively. CONCLUSIONS Positive rest perfusion imaging accurately identified patients at high risk for adverse cardiac outcomes, whereas negative perfusion imaging identified a low risk patient group. Early perfusion imaging allows for rapid and accurate risk stratification of emergency department patients with possible cardiac ischemia and nondiagnostic ECGs.

Impact of the troponin standard on the prevalence of acute myocardial infarction

BACKGROUND Recent recommendations are that troponin should replace creatine kinase (CK)-MB as the diagnostic standard for myocardial infarction (MI). The impact of this change has not been well described. Our objective was to determine the impact of a troponin standard on the prevalence of acute non-ST-elevation MI. METHODS The current study was a retrospective analysis of consecutive patients without ST-segment elevation admitted for exclusion of myocardial ischemia to an inner city urban tertiary care center. All patients underwent serial marker sampling (CK, CK-MB, and cardiac troponin I [cTnI]). Patients with ST elevation consistent with acute MI (n = 130) or who did not have an 8 hour cTnI (n = 124) were excluded. The impact of 3 different cTnI diagnostic values were examined in 2181 patients: the lower limit of detectability (LLD); an optimal diagnostic value (OPT), chosen using receiver operator characteristic curve analysis; and the manufacturers suggested upper reference level (URL), when compared to a gold standard CK-MB MI definition. In addition, MI prevalence was assessed using different CK-MB MI definitions and evaluated in patients with ischemic changes only. RESULTS The prevalence CK-MB MI was 7.8%. Using the various cTnI diagnostic values, the incidence of MI increased the prevalence by 28% to 195%. Using the optimal diagnostic value for cTnI, patients with cTnI elevations not meeting CK-MB MI criteria had an intermediate 30-day mortality (5.4%) compared to those with CK-MB MI (7.1%). Grouping the cTnI positive, CK-MB MI negative patients with the CK-MB MI patients rather than the non-CK-MB MI patients reduced mortality for both the MI (to 5.9%) and non-MI groups (from 1.9% to 1.6%). CONCLUSIONS Changing to a troponin standard will have a substantial impact on the number of patients diagnosed with MI. The revised definition for MI will have important clinical and health care implications.

Ability of troponin I to predict cardiac events in patients admitted from the emergency department

OBJECTIVES We sought to determine the predictive ability of troponin I (TnI) in a heterogeneous group of patients with chest pain admitted from the emergency department (ED) for exclusion of myocardial infarction (MI). BACKGROUND Previous studies in high-risk patients demonstrated that troponin elevations are associated with increased cardiac events. Little information is available on its predictive ability in more heterogeneous, lower risk patients. METHODS Consecutive patients admitted from the ED for possible MI underwent serial myocardial marker sampling of TnI and creatine kinase, CK-MB over an 8-h period. Patients with ST segment elevation were excluded. End points included MI, death, significant complications (e.g., cardiac or respiratory arrest, intra-aortic balloon pump, pulmonary artery catheter or pacemaker placement, revascularization or inotropic infusion) and significant disease. RESULTS Events occurred in 513 (27%) of the 1,929 patients evaluated: MI in 175 (9.1%) and death in 34 (1.8%); an additional 248 patients (13%) without MI had complications, and 323 (17%) without MI had significant disease. Sensitivity of TnI for MI was high (96%). Patients without MI who were TnI-positive were more likely to have complications (43% vs. 12%) or significant disease (41% vs. 17%) as compared with those who were TnI-negative; however, the sensitivity of TnI for these two end points was low (14% and 21%, respectively). Predictive values were unchanged after excluding patients with ischemic electrocardiograms. CONCLUSIONS Troponin I had a high sensitivity for MI when used as part of a rapid rule-in protocol; however, the sensitivity for other end points was low. Use of TnI alone failed to identify the majority of patients who had either significant disease or complications.

Early diagnosis of acute myocardial infarction in patients without ST-segment elevation.

Early identification of acute myocardial infarction (AMI) is necessary to initiate appropriate treatment. In patients presenting without ST-segment elevation, diagnosis is often dependent on the presence of elevated myocardial markers. This study examines the ability of serial MB mass alone and in combination with myoglobin in diagnosing AMI in patients without ST-segment elevation within 3 hours of presentation. In all, 2,093 patients were admitted and underwent serial marker analysis using myoglobin, creatine kinase (CK), and CK-MB at 0, 3, 6, and 8 hours. AMI was diagnosed by a CK-MB > or =8.0 ng/ml and a relative index (RI) (CK-MB x 100/total CK) > or =4.0. A total of 186 patients (9%) were diagnosed with AMI. The optimal diagnostic strategy was an elevated CK-MB + RI on the initial or 3-hour sample or at least a twofold increase in CK-MB without exceeding the upper range of normal over the 3-hour time period (sensitivity 93%, specificity 98%). The combination of an elevated CK-MB + RI or myoglobin on the initial or 3-hour sample had a sensitivity of 94%, although specificity was significantly lower, at 86%. Sensitivities and specificities after exclusion of the 242 patients with ischemic electrocardiographic changes were essentially unchanged. We conclude that most patients with AMI presenting with nondiagnostic electrocardiograms can be diagnosed within 3 hours of presentation.

Myocardial perfusion imaging with technetium-99m sestamibi in patients with cocaine-associated chest Pain

STUDY OBJECTIVE To describe the characteristics and outcome in patients presenting to the emergency department with chest pain associated with cocaine use, the majority of whom underwent early rest perfusion imaging. METHODS From January 1994 to June 1996, 218 patients had 241 ED visits for evaluation of symptoms consistent with myocardial ischemia after cocaine use. High-risk patients (N=25) were admitted directly to the CCU for exclusion of myocardial infarction (MI). Moderate- to low-risk patients (N=216) were promptly injected with technetium-99m sestamibi in the ED and underwent gated myocardial perfusion imaging 60 to 90 minutes later. Moderate-risk patients were observed in the CCU, whereas low-risk patients with negative perfusion imaging results were discharged home directly from the ED. RESULTS A diagnosis of MI was made in 6 patients, 4 of whom had ECG findings consistent with MI. Of the 216 patients who underwent perfusion imaging, 5 had positive study results, including 2 with MI. None of the 38 patients with negative results after perfusion imaging who were admitted to the CCU had a diagnosis of MI. Only 6 of the 67 patients undergoing stress perfusion imaging had reversible perfusion defects. At 30-day follow-up, there were no cardiac events in patients with negative results after rest perfusion imaging. CONCLUSION Acute MI is infrequent in patients presenting with cocaine-associated chest pain. Positive results after rest perfusion imaging are uncommon, suggesting that myocardial ischemia is infrequently the cause of cocaine-associated chest pain. Early perfusion imaging may offer an effective alternative to routine CCU admission of patients with cocaine-related cardiac symptoms.

Coronary angiographic findings in patients with cocaine-associated chest pain ☆

Patients who present to the Emergency Department (ED) with chest pain associated with cocaine use are a common problem. The incidence and predictors of underlying significant coronary disease in patients with and without myocardial infarction (MI) has not been well described. Patients who underwent coronary angiography within 5 weeks of an ED evaluation for cocaine-associated chest pain were studied. Significant disease was defined as > or = 50% stenosis of a coronary artery or major branches or bypass graft. A total of 90 patients underwent coronary angiography. Significant disease was present in 45 (50%), with 1-vessel disease in 32%, 2-vessel disease in 10%, 3-vessel disease in 6%, with significant graft stenosis in 3%. Significant disease was present in 77% of patients with MI or troponin I elevations, compared to only 35% of patients without myonecrosis. Predictors of significant coronary disease included MI or troponin I elevations, prior MI, known coronary disease (prior MI or revascularization), and elevated cholesterol. Only 7 of the 39 patients (18%) without myonecrosis or a history of coronary disease had significant disease on angiography. In conclusion, significant disease is found in the majority of patients with cocaine-associated MI or troponin elevations. In contrast, only a minority of those without myonecrosis have significant coronary disease.

A comprehensive strategy for the evaluation and triage of the chest pain patient: a cost comparison study ☆

BackgroundOur objective was to determine the cost-effectiveness of a comprehensive, risk-based triage system, composed of multiple critical pathways, with the use of early myocardial perfusion imaging (MPI) in low-risk patients. We found previously that a chest pain evaluation system that uses MPI in low-risk patients was safe and effective, but the costeffectiveness of this approach was not studied.Methods and ResultsWe compared two groups. The Acute Cardiac Team (ACT) group (n = 874) was assigned prospectively to 1 of 4 risk levels by emergency department (ED) physicians. Level 1, 2, and 3 patients were admitted; level 4 patients were evaluated in the ED. Level 3 and 4 patients underwent ED MPI. The control group (n = 713) represented consecutive patients evaluated in the prior year according to standard care and assigned retrospectively to an ACT level based on the presenting electrocardiographic and clinical data. Record and hospital administrative data were assessed for clinical variables, outcomes, lengths of stay, and all expenses incurred within 30 days of the index visit. The baseline characteristics of the two groups were similar, including age, sex, myocardial infarction prevalence, and 30-day revascularization rates within each level or between the two groups. Mean costs per encounter were reduced for the ACT patients for each level, which was significant when all patients were compared (

Utility of Troponin I in Patients with Cocaine‐associated Chest Pain

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