Effect of smoking marihuana and of a high‐nicotine cigarette on angina pectoris

Abstract

The purpose of this study was to determine the effect of smoking marihuana and of high-nicotine cigarettes on exercise-induced angina pectoris. Smoking 1 marihuana cigarette increased the resting product of systolic blood pressure times heart rate 54%, increased the venous carboxyhemoglobin level, and decreased the exercise time until angina 50% in 10 patients with angina pectoris. Smoking 1 high-nicotine cigarette increased the resting product of systolic blood pressure times heart rate 36%, increased the venous carboxyhemoglobin level, and decreased the exercise time until angina 23%. Smoking either marihuana or high-nicotine cigarettes decreases exercise performance until angina by increasing myocardial oxygen demand and by decreasing myocardial oxygen delivery. Smoking 1 marihuana cigarette decreased the exercise time until angina more than smoking 1 high-nicotine cigarette (p less than 0.001).

Cannabinoids and Atherosclerotic Coronary Heart Disease

“…In this study, a single marijuana cigarette decreased the exercise time to angina by an average of 48% as compared to 23% after smoking a tobacco cigarette. 46 The impact of marijuana smoking on mortality in patients with known CAD was investigated in a study by Mukamal et al 47 In this retrospective study, there was a trend toward increased cardiovascular mortality in marijuana users (hazard ratio: 1.9; 95% confidence interval: 0.6-6.3). Interestingly, there was ∼3-fold increased mortality following myocardial infarction in marijuana users as compared to nonmarijuana users.…”

Triggering Myocardial Infarction by Marijuana

“…27,28 In addition to the hemodynamic effects, smoked marijuana is associated with an increase in carboxyhemoglobin, resulting in decreased oxygen-carrying capacity. 3,5,11 Whether marijuana affects the hemostatic balance is unclear. Marijuana may increase factor VII activity; however, there are mixed results in terms of the effects of smoked marijuana on platelet function.…”

“…Aronow and Cassidy 3,11 demonstrated that among patients with chronic stable angina, the anginal threshold is acutely diminished after smoking a single marijuana cigarette. In particular, the exercise time to angina was decreased by an average of 48% after smoking a single marijuana cigarette, compared with an 8.6% decrease after smoking a marijuana placebo (marijuana cigarette with no delta-9-tetrahydrocannabinol) and a 23% decrease after smoking a high nicotine tobacco cigarette.…”

“…In particular, the exercise time to angina was decreased by an average of 48% after smoking a single marijuana cigarette, compared with an 8.6% decrease after smoking a marijuana placebo (marijuana cigarette with no delta-9-tetrahydrocannabinol) and a 23% decrease after smoking a high nicotine tobacco cigarette. 3,11 Thus, some marijuana-associated infarctions may be caused by a myocardial oxygen supply that is inadequate to cope with the increased oxygen demands that occur as result of smoking marijuana. However, the culprit lesion in a majority of myocardial infarctions occurs at the site of a disrupted atherosclerotic plaque.…”

“…Overall, there is a net increase in myocardial oxygen demand with a decrease in oxygen supply, which is due in part to an increase in carboxyhemoglobin 3 ; this results in a lower anginal threshold in patients with chronic stable angina. 3,11 Furthermore, there are several reports of myocardial infarction occurring in close proximity to marijuana use in otherwise low-risk individuals. [12][13][14] An Institute of Medicine report on marijuana and medicine released in 1999 noted that although the cardiovascular effects of marijuana do not seem to pose a health problem for healthy young users, they may present a serious problem for older subjects.…”