Results from these two separate studies indicate that smoking cannabis may substantially expand the risk of stroke and bleeding following PCI procedures such as angioplasty or stent placement. Comparably, marijuana users who had MI or PCI procedures such as angioplasty or stent placement were more likely to be readmitted to the hospital for a second MI or cardiac procedure than non-users.
In one multicenter study, researchers examined the incidence and effect of marijuana use on hospital admissions in patients with previous heart attacks and revascularization procedures. Researchers analyzed the National Inpatient Sample to assess the rate of hospital admissions in patients with a history of previous MI, PCI, and/or coronary artery bypass grafting (CABG), and self-identified marijuana users and nonusers from 2007 to 2014. The database, which contains information on 8 million hospital stays annually, does not include details about smoking or eating or other forms of marijuana consumption. It is important to note that several states legalized or decriminalized medical and/or recreational marijuana during the study’s time frame.
The researchers found the following: 1) a 250% relative increase in cannabis use among patients who had survived an MI or revascularization; 2) 67% of the MI survivors who utilized cannabis had a subsequent MI versus 41% of noncannabis users; and 3) cannabis users had elevated rates of hospitalizations for recurrent PCI and CABG. They also indicated that marijuana users were more likely to be middle aged (average age 52 years vs. a median age of 72 years for nonusers); African American (34% vs. 10% of nonusers); and male (77% vs. 62% of nonusers).
In addition, cannabis users had a lower incidence of hypertension (71.7% vs. 74.8%), diabetes (23.6% vs. 32.9%) and dyslipidemia (51.3% vs. 57.8%; P < .001). Researchers also found that the increasing trend of cannabis use was accompanied by a greater rate of AMI (7.2% vs 4.5%), PCI (6.2% vs 5.5%) and CABG (1.9% vs 1.5%) compared with nonusers. Moreover, all-cause mortality (0.8% vs 2.5%) and hospital charges ($21,556 vs. $24,872) were low among cannabis users. However, subsequent acute MI was more widespread among cannabis user compared with nonusers (67% vs. 41%).
In a press release, lead author of the study, Rushik Bhuva, M.D., a cardiology fellow with the Wright Center for Community Health in Scranton, Pennsylvania stated, “There was an alarming rise in the trend of cannabis use among patients who have already had a heart attack or coronary revascularization procedure during the study period. Another concerning finding was that the frequency of recurrent heart attacks and cardiac interventions was higher among cannabis users, even though they were younger and had fewer risk factors for heart disease.” Additionally, Dr. Bhuva stated, “Spreading awareness regarding the potential risk of recurrent heart attacks in middle-aged, African American and male cannabis users and screening them at an earlier age for potential risk factors of future heart attacks should be encouraged among clinicians. In addition, the role of medicinal cannabis, its benefits and potential risks with regards to cardiovascular management need to be validated in larger studies.”
In the second presentation, Dr. Sang Gune Yoo, an internal medicine resident physician at the University of Michigan and colleagues evaluated the statewide Blue Cross Blue Shield Michigan Cardiovascular Consortium (N = 113,477; 3.5% self-identified cannabis users) to ascertain the relationship between cannabis use and in-hospital outcomes after PCI.
Cannabis users were matched one-to-one with nonusers and evaluated for the primary outcome, which involved postprocedural stroke, transfusion, bleeding, acute kidney injury, and death. They found that patients who smoked marijuana and underwent angioplasty were an average age of 54 years and 79% were male. The cannabis user group had a high prevalence of cigarette smokers (73% vs. 26.8%) and were more likely to present with ST-elevation MI (27.3% vs. 15.9%).
Dr. Yoo et al revealed that after PCI, cannabis users experienced a higher risk for bleeding (adjusted odds ratio [OR] = 1.54; 95% CI, 1.2-1.97; P < .001) and stroke (aOR = 11.01; 95% CI, 1.32-91.67; P = .026), and a diminished risk for acute kidney injury (aOR = 0.61; 0.42-0.87; P = .007).
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