Clinical Characteristics and Angiographic Findings of Myocardial Infarction among Marijuana Users and Non-Users

Marijuana use has been increasingly legalized in the United States resulting in substantial rise in the number of users especially in the younger populations. While our group and others had described various metabolic effects of this drug, little is known about its association with acute myocardial infarction (AMI).

This follow up study presents contemporaneous cohort of non-THC user patients at a single, urban center hospital diagnosed with ST-elevation AMI; highlighting and comparing demographic, clinical, laboratory and angiographic characteristics based on exposure to THC at time of presentation.

Retrospective chart review of patients with ST-elevation AMI presenting to our inner city hospital Coronary Care Unit over a period of 4 years (December 2013-April 2017).

Of the 10 case subjects studied whom presented with chest pain, EKG evidence of ST-elevation MI (STEMI) with cannabis use, mean age at presentation was 40 years old, which was 10 years younger than our control group with no marijuana use (n = 11, p = 0.107). Of the patients who had marijuana exposure upon admission, 3 (30%) had no known cardiovascular disease (CVD) risk factors (RF) on admission, 1 patient had 3 RF, 4 patients had 2 RF and 2 had 1 CVD risk factor, which included age, diabetes mellitus type 2 (DM2), hypertension, dyslipidemia, smoking status, and family history at time of triage. Patients who were negative for marijuana use had higher number of CVD risk factors present upon admission. ASCVD risk scores were 10% vs. 16% (p = 0.312). In angiographic findings, 100% of the marijuana users had 1 vessel disease compared with 55% in the non-users (p = 0.0351). Severity of stenosis for both groups was averaged at 93% for non-users vs 95% in THC users (p = 0.62414). Collateral vessels were visible during coronary arteriogram in 91% of non-THC users and in only 20% of THC users (p = 0.0019). Furthermore, non-users had 35% higher rate of Rentrop grade 1 collaterals (55% vs. 20%, p = 0.4872). Similar difference was shown in grade 2 collaterals between the two groups with non-users having 36% higher rate (36% vs. 0%, p = 0.0902). Amongst the patients who had collateral circulation present at the time of angiography (Rentrop grade >0), good collaterals (Rentrop grade 2 or 3) were present in 40% of non-THC users, while there was 0% presence of grade 2+ collaterals in THC users (p = 0.5152).

In our study, marijuana use is associated with ST-elevation MI in largely minority population, occurring at a relatively younger age with half of the cases CVD risk free. Additional studies are needed to further characterize this population given the increase in marijuana use.