Cocaine and vasospasm

Article Abstract:

Over the past ten years research has indicated that the abuse of cocaine may induce myocardial infarction, MI (heart attack). Results of coronary angiography, X-rays of the heart and coronary arteries, performed in 45 reported cases of cocaine related MI, indicate that these events are caused by a spasm in the coronary arteries (which supply oxygen to the heart muscle). The authors describe previous research on the effects of cocaine, particularly on the cardiovascular system. Studies discussed include cocaine experimentation with animal models, and observations of the effects of cocaine used in conjunction with norepinephrine, a hormone which constricts blood vessels. An evaluation of these studies indicates that cocaine alters coronary vessel reactivity; this is consistent with the theory that vasospasm occurs in the coronary arteries. The authors point out that this cocaine-induced effect may be attributed to more than one factor. Reports of episodes of pulmonary hemorrhage, stroke, and rhabdomyolysis (an acute disease of skeletal muscle) suggest a more complex pattern of action. These abnormalities may be caused by a cocaine metabolite or even a contaminant of the drug. Another unexplained question is why there is a relatively low occurrence of cardiac episodes, given the current widespread recreational use of cocaine. Cocaine blood levels in Andean Indians are similar to levels recorded in abusers in this country, but no pattern of cardiac disease has been documented in the South American group. Cardiovascular toxicity represents a relatively small portion of the damage that is caused by the abuse of cocaine. The high purity of recreational cocaine now available will unfortunately provide many additional cases for future medical research.

Abnormalities, Causes of, Complications and side effects, Cardiovascular system, Circulatory system, editorial, Coronary vasospasm

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Relation between activated smooth-muscle cells in coronary-artery lesions and restenosis after atherectomy

Article Abstract:

Detection of the nonmuscle form of the myosin protein in atherosclerotic plaques removed from diseased coronary arteries may predict who will develop restenosis (recurrent disease) after atherectomy. Atherectomy uses a catheter with a hollow tube at the end that has a 'window' that doctors can use to scrape plaque from the inside of the coronary arteries. Plaque removed from the coronary arteries of 20 patients with coronary artery disease was tested for the presence of nonmuscle myosin using RNA hybridization. Samples from 10 patients tested positive, and angiography detected recurrent disease in seven of the patients an average of six months after atherectomy. All seven required further treatment. However, only one of the 10 patients who tested negative for nonmuscle myosin developed recurrent disease. Nonmuscle myosin only occurs in smooth muscle when it is actively proliferating. Smooth muscle proliferation is a contributing factor to the development of atherosclerosis.

Measurement, Coronary heart disease, Myosin, Arterial occlusive diseases

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Reversible cardiomyopathy associated with cocaine intoxication

Article Abstract:

Cocaine can have serious, and sometimes fatal, side effects involving the heart and blood vessels. Dilated cardiomyopathy, in which the chambers of the heart become enlarged and the heart muscle contracts with reduced force, has been an uncommon consequence of cocaine use. An example of dilated cardiomyopathy was observed when a 35-year-old woman was admitted to the emergency room for seizures after a day-long "crack"-smoking binge. Pressure measurement permitted estimation of the fraction of ejected blood to be roughly 10 percent (65 percent is normal), indicating poor heart pumping function. By day eight, the patient's blood pressure returned to normal and she no longer required treatment with pressor agents, which act to raise blood pressure. She was discharged on day 16; a sequence of echocardiographic images showed the return of the enlarged left ventricle to normal proportions during her treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Cardiomyopathy, Myocardial diseases, Heart enlargement, Heart hypertrophy

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