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Is Marijuana Good or Bad for Endothelial Function?

J Appl Physiol 2021 Jan 14.
Habitual Cannabis Use is Associated with Altered Cardiac Mechanics and Arterial Stiffness, but not Endothelial Function in Young Healthy Smokers
Affiliations
  • 1 Human Health and Nutritional Sciences, University of Guelph, Canada.
  • 2 University of Guelph, Canada.
  • 3 Department of Human Health and Nutritional Sciences, University of Guelph, Canada.
Corresponding Author; email: ccheun05@uoguelph.ca
Abstract
Cigarette smoking is amongst the most detrimental behaviours to cardiovascular health, resulting in arterial stiffening, endothelial dysfunction, and structural/functional alterations to the myocardium. Similar to cigarettes, cannabis is commonly smoked and next to alcohol, is the most commonly used recreational substance in the world. Despite this, little is known about the long-term cardiovascular effects of smoking cannabis. This study explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants (n=35). Using echocardiography, carotid-femoral pulse wave velocity (cfPWV), and brachial flow-mediated dilation (FMD) we performed a cross-sectional assessment of cardiovascular function in cannabis users (n=18), and controls (n=17). There were no differences in cardiac morphology or traditional resting measures of systolic or diastolic function between cannabis users and controls (all p>0.05); whereas cannabis users demonstrated reduced peak apical rotation compared to controls (cannabis users: 5.5±3.8, controls: 9.6±1.5; p = 0.02). Cannabis users had higher cfPWV compared to controls (cannabis users: 5.8±0.6m/s, controls: 5.3±0.7m/s; p = 0.05), while FMD was similar between cannabis users and controls (cannabis users: 8.3±3.3%, controls: 6.8±3.6%; p= 0.7). Young, healthy, cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness. Further studies should explore causal links between cannabis smoking and altered cardiovascular function.
Keywords: Echocardiography; Flow-Mediated Dilation; Marijuana; Pulse Wave Velocity; Smoking.
One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function [in rats!]
  • 1Cardiovascular Research Institute, University of California, San Francisco.
  • 2 Division of Cardiology, University of California, San Francisco Department of Cardiovascular Surgery & Electro-chemotherapy, China-Japan Friendship Hospital, Beijing, People’s Republic of China.
  • 3 Cardiovascular Research Institute, University of California, San Francisco Division of Cardiology, University of California, San Francisco.
  • 4 Division of Cardiology, University of California, San Francisco.
  • 5 Division of Cardiology, University of California, San Francisco Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco.
  • 6 Division of Occupational and Environmental Medicine, University of California, San Francisco.
  • 7 Cardiovascular Research Institute, University of California, San Francisco Division of Cardiology, University of California, San Francisco Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco matt.springer@ucsf.edu.
Conclusions
One minute of exposure to marijuana SHS substantially impairs endothelial function in rats for at least 90 minutes, considerably longer than comparable impairment by tobacco SHS. Impairment of FMD does not require cannabinoids, nicotine, or rolling paper smoke. Our findings in rats suggest that SHS can exert similar adverse cardiovascular effects regardless of whether it is from tobacco or marijuana.
Keywords: artery, cannabis, endothelium, flow‐mediated dilation, marijuana, nitric oxide synthase, secondhand smoke, smoking, vasodilation
Am J Med Case Rep 2020;8(7):216-220
Marijuana-induced Coronary Vasospasm and Myocardial Infarction: A Case Report and Review of Literature
Affiliation
  • 1Department of Internal Medicine, Division of Cardiovascular Disease, State University of New York, Downstate Health Sciences Center, Brooklyn, N.Y, USA – 11203.
Abstract
The usage of marijuana and its legalization has been growing rapidly, being abused by a wide range of age groups. Its effects on the heart are well known, but coronary artery vasospasm causing ST elevation myocardial infarction (STEMI) from Marijuana alone is rather lesser known. Herein, we report a case of a middle aged African American man with a significant tobacco smoking history who presented with chest pain typical of myocardial infarction (MI) soon after smoking marijuana. ECG showed ST elevation in inferior leads with first degree AV block and a urine drug screen positive only for marijuana. Coronary angiogram showed mid right coronary artery (RCA) obstruction which was relieved upon injection of intracoronary nitroglycerine. This case report reinstates the significance of considering substance abuse as an etiology of STEMI during initial presentation, ruling out with urine drug samples. We also present a literature review of coronary vasospasm with STEMI, induced specifically by Marijuana and its pathophysiologic mechanisms.
Keywords: ST-segment elevation myocardial infarction; cannabinoid receptors; demand ischemia; marijuana; vascular endothelial dysfunction.
Figure 1. ST elevation in leads II, III and aVF and ST segment depression in leads aVL, V4, V5 consistent with inferior infarction with reciprocal changes, premature ventricular complex, and first-degree heart block
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