COCAINE-ASSOCIATED CHEST PAIN: HOW COMMON IS MYOCARDIAL INFARCTION?

Weber JE, et al. Acad Emerg Med 2000 Aug;7(8):873-7

OBJECTIVE: Prior studies addressing the incidence of acute myocardial infarction (AMI) in patients with cocaine-associated chest pain have found divergent results. Previous prospective studies, which found approximately a 6% incidence of AMI, have been criticized for selection bias. This study sought to determine the rate of AMI in patients with cocaine-associated chest pain.

METHODS: All patients seen in an urban university-affiliated hospital between July 1996 and February 1998 were identified by ICD-9 medical records search for cocaine use and chest pain/ acute coronary syndromes. In this system, all faculty admit all patients with cocaine-associated chest pain for at least 23-hour observation periods. Data collected included demographics, medical and cocaine use history, presenting characteristics, hospital course, cardiovascular complications, and diagnostic tests using a 119-item closed-question data instrument with high interrater reliability. The main outcome measure was AMI according to World Health Organization (WHO) criteria.

RESULTS: There were 250 patients identified with a mean age of 33.5 +/- 8.5 years; 77% were male; 84% were African American. Of 196 patients tested, 185 had cocaine or cocaine metabolites in the urine (94%). The incidence of cardiac risk factors were: hypercholesterolemia, 8%; diabetes, 6%; family history, 34%; hypertension, 26%; tobacco use, 77%; prior MI, 6%; and prior chest pain, 40%. Seventy-seven percent admitted to cocaine use in the preceding 24 hours: crack, 85%; IV, 2%; nasal, 6%. Twenty-five patients (10%) had electrocardiographic evidence of ischemia. A total of 15 patients experienced an AMI (6%; 95% CI = 4.1% to 8.9%) using WHO criteria. Complications were infrequent: bradydysrrhythmias, 0.4%; congestive heart failure, 0.4%; supraventricular tachycardia, 1.2%; sustained ventricular tachycardia, 0.8%.

CONCLUSION: The incidence of AMI was 6% in patients with cocaine-associated chest pain. This result is identical to that found in prior prospective studies.

COCAINE-ASSOCIATED CHEST PAIN: ONE-YEAR FOLLOW-UP.

Hollander JE, et al. Acad Emerg Med 1995 Mar;2(3):179-84

OBJECTIVE: To determine the one-year mortality and incidence of myocardial infarction (MI) post-hospital discharge or ED release for patients with cocaine-associated chest pain.

METHODS: A prospective, observational study of an inception cohort of consecutive patients who presented to one of four municipal hospital EDs with cocaine-associated chest pain. Patients were followed for one year from the end of the enrollment period. Main outcome parameters were the one-year actuarial survival and the frequency of nonfatal MI.

RESULTS: Mortality data were available for all 203 patients at a mean of 408 days. Additional clinical information was available for 185 patients (91%). There were six deaths (one-year actuarial survival 98%; 95% CI, 95-100%); none from MI. Nonfatal MI occurred in two patients (1%; 95% CI, 0-2%). Continued cocaine use was common (60%; 95% CI, 52-68%) and was associated with recurrent chest pain (75% vs 31%, p < 0.0001). No MI or death was reported for patients who claimed to have ceased cocaine use.

CONCLUSIONS: Patients who presented with cocaine-associated chest pain commonly continued to use cocaine after discharge. Urgent evaluation of coronary anatomy or cardiac stress tests may not be necessary for patients for whom MI is ruled out and who do not have recurrent potentially ischemic pain. The subsequent risk for MI and death in this group appears to be low. Intervention strategies should emphasize cessation of cocaine use.

PROSPECTIVE MULTICENTER EVALUATION OF COCAINE-ASSOCIATED CHEST PAIN. COCAINE ASSOCIATED CHEST PAIN (COCHPA) STUDY GROUP.

Hollander JE, et al. Acad Emerg Med 1994 Jul-Aug;1(4):330-9

OBJECTIVE: To describe a large cohort of patients who had chest pain following cocaine use, and to determine the incidence of and clinical characteristics predictive for myocardial infarction in this group of patients.

METHODS: A prospective observational cohort study of consecutive patients with cocaine-associated chest pain was conducted in six municipal hospital emergency departments (EDs). Demographic variables, drug abuse patterns, medical histories, chest pain characteristics, ECG results, and laboratory data were recorded. Myocardial infarction was the primary endpoint.

RESULTS: Fourteen of 246 patients (5.7%; 95% confidence interval [CI], 2.7-8.7%) had myocardial infarction, as diagnosed by elevated CK-MB isoenzyme levels. There were two deaths (0.8%). The patients had a median age of 33 years. The majority were male (71.5%), non-white (83.3%), cigarette smokers (83.3%) who used cocaine regularly. Chest pain began a median of 60 minutes after cocaine use and persisted for a median of 120 minutes. Chest pain was most frequently described as substernal (71.3%) and pressure-like (46.7%). Shortness of breath (59.3%) and diaphoresis (38.6%) were common. There was no clinical difference between patients who had myocardial infarctions and those who did not. Twelve patients had arrhythmias and four had congestive heart failure. All cases requiring intervention were evident upon presentation. An ECG revealing ischemia or infarction had a sensitivity of 35.7% for predicting a myocardial infarction. The specificity, positive predictive value, and negative predictive value of the ECGs were 89.9%, 17.9%, and 95.8%, respectively.

CONCLUSIONS: Myocardial infarction in patients who have cocaine-associated chest pain is not uncommon. No clinical parameter available to the physician can adequately identify patients at very low risk for myocardial infarction. Therefore, all patients with cocaine-associated chest pain should be evaluated for myocardial infarction.