Marijuana Use in Patients With Cardiovascular Disease: JACC Review Topic of the Week

Abstract

Marijuana use is increasing as more states are legalizing cannabis for both medicinal and recreational purposes. National survey data estimate that >2 million Americans with established cardiovascular diseases currently use or have used marijuana in its variety of forms, including inhalation and vaping. Cannabinoid receptors are distributed in multiple tissue beds and cells, including platelets, adipose tissue, and myocytes. Observational data suggest associations between marijuana and a broad range of adverse cardiovascular risks. Marijuana is becoming increasingly potent, and smoking marijuana carries many of the same cardiovascular health hazards as smoking tobacco. Synthetic cannabinoids have been linked to more sustained and deleterious pharmacodynamic effects. Marijuana is classified as a Schedule I substance, thus limiting its rigorous study for cardiovascular health effects. This review summarizes cardiovascular considerations related to marijuana use, pharmacological interactions, and future steps to provide clearer guidance regarding its cardiovascular safety. Screening for marijuana use is encouraged, especially in young patients presenting with cardiovascular disease.

Keywords: arrhythmia; cannabis; coronary artery disease; marijuana; vascular disease.

Figure 1.. Intracellular mechanisms of marijuana effects

Cannabinoid receptor 1 (CB1R) is typically located on the cell surface and generally inhibits cyclic adenosine monophosphate (cAMP) formation that in turn decreases calcium influx. It can be internalized as a ligand-induced receptor mediating signaling pathways via β-arrestin. In contrast, intracellular CB1Rs do not translocate and can increase intracellular calcium through release of internal lysosomal calcium stores via increased membrane permeability. Additionally, CB1Rs located in mitochondria will decrease mitochondrial respiration and cAMP formation, thus regulating cellular energy metabolism.

Figure 2.. Reported use (in thousands) of marijuana in the last year, from 2016-2017 National Survey on Drug Use and Health

Data were extracted from the National Survey on Drug Use and Health, an annual survey of the US civilian, non-institutionalized population, in 2016-2017. Across the US, over 39 million respondents reported use of marijuana in the last year. Mapping software was powered by Bing (GeoNames, HERE, MSFT).

Figure 3.. Estimated 1.7 to 2.7 million adults reporting prior or current marijuana use who have cardiovascular disease, 2005-2016 from National Health and Nutrition Examination Survey (NHANES)

Marijuana use was defined as those responding “yes” to ever using hashish or marijuana. Cardiovascular (CV) disease was defined broadly as those responding “yes” to being ever told by a healthcare provider they had congestive heart failure, coronary heart disease, or a heart attack. Response rates to both questions ranged from 49.3% to 51.5% throughout the study timeframe.

Figure 4.. Potential mechanisms of cardiovascular (CV) risk with exposure to marijuana

The quality of evidence supporting these posited mechanistic relationships is modest.

Central Illustration.. Practical approach to screening for marijuana use among patients with cardiovascular disease

In light of the accumulating data regarding marijuana use and cardiovascular effects, it is increasingly important for clinicians to screen patients for use, educate about its potential effects, and contribute to ongoing research in the field.