Coronary Angiography and Cocaine-Associated Chest Pain

Abstract & Commentary

Source: Kontos MC, et al. Coronary angiographic findings in patients with cocaine-associated chest pain. J Emerg Med 2003;24:9-13.

Whether coronary angiography is indicated in patients with cocaine-associated myocardial infarction (MI), let alone chest pain, is not clear. This paper from the Medical College of Virginia examined the issue, using primarily prospective observational data on consecutive patients admitted for evaluation of chest pain associated with historical or laboratory evidence of cocaine use. Patients were included if they underwent coronary angiography within five weeks of emergency department (ED) evaluation. The institution employs a tiered structure of triage and disposition for chest pain patients. Based upon risk stratification, the history and physical are supplemented with electrocardiography, serum markers, and nuclear imaging, as well as close follow-up of those discharged from the ED with a negative initial work-up for cardiac ischemia.1

Reasonable criteria were used for biomarker or electrocardiographic evidence of MI. For the purposes of this study, "significant" coronary artery disease (CAD) by angiography was defined as > 50% stenosis of at least one vessel. Of 734 patients who were evaluated for symptoms consistent with myocardial ischemia after cocaine use, 90 underwent coronary angiography within five weeks. Mean patient age was 42, and roughly two-thirds were male. Approximately one-third had evidence of prior coronary artery disease, and MI was evident by either CPK-MB and/or cardiac troponin I (TnI) in 31 patients (34%). Criteria for angiography are listed in the Table.

Significant CAD was found in 45 patients (50%); most of who had single-vessel disease. Of the 31 patients with MI by CPK-MB or TnI, 24 (77%) had significant disease on angiography. Patients without evidence of myonecrosis (the remaining 59 patients)—but with significant CAD on angiography—were more likely (p < 0.01) to have prior MI, prior revascularization, a history of CAD, or an increased cholesterol. The authors conclude that the majority of patients with cocaine-associated MI have significant CAD. Similar patients without myonecrosis have a low incidence of CAD; therefore, coronary angiography is not the best first test for evaluation for ischemia in this group.

Commentary by Richard A. Harrigan, MD, FAAEM

The authors readily acknowledge that this prospective observational study is limited due to its single location, and the likelihood that not all patients with cocaine-associated chest pain were captured. Another point of importance, however, is that only 90 of 734 (13%) underwent coronary angiography within five weeks. Keeping that in mind, the conclusion that "the majority of patients with cocaine-associated MI have significant CAD" is true—for those who end up on the angiography table (i.e., for those in their cohort). As in any observational study, the diagnostic evaluation was left up to the treating (in this case, critical care unit attending) physician. It would be interesting to know how many of the original 734 patients who did not undergo coronary angiography "ruled-in" by cardiac enzymes. The reader must be careful—the temptation to generalize this data to our population (ED patients with evidence of myonecrosis by serum enzymes) from the study population (ED patients with evidence of myonecrosis by serum enzymes—who ultimately underwent coronary angiography within five weeks) is flawed. This study does remind us, however, that cocaine-associated chest pain can be "serious" chest pain—with underlying CAD.

Dr. Harrigan, Associate Professor of Emergency Medicine, Temple University Hospital and School of Medicine, Philadelphia, PA, is Editor of Emergency Medicine Alert.

References

1. Tatum JL, et al. Comprehensive strategy for the evaluation and triage of the chest pain patient. Ann Emerg Med 1997;29:116-123.