Cocaine Linked to Heart Attack, Stroke

Researchers Find Cocaine Increases Blood Clotting Factors

Heart Patient
Heart Problems Common in Cocaine Users. © Getty Images

Using cocaine can be dangerous because the drug can narrow the blood vessels and increase the user's blood pressure and heart rate. Because cocaine has these effects it can increase the risk of sudden heart attack and stroke.

There is some evidence that cocaine use can induce heart attacks and strokes in people who otherwise are not at high risk for these cardiovascular events, which sometimes can be fatal.

On study found that within the first hour after using cocaine, users are 24 times more likely to experience a myocardial infarction (heart attack). That increased risk decreases rapidly after an hour, but the danger is significantly heightened immediately following use.

But, the danger does not complete disappear after the first hour. Other studies have identified changes in blood components that may also play a role in cocaine-related heart attack and stroke hours after initial use.

Risk Factors for Heart Attack

Dr. Arthur Siegel and his colleagues at the Alcohol and Drug Abuse Research Center at McLean Hospital in Belmont, Massachusetts studied the effect of cocaine on blood factors that respond to inflammation by promoting clotting to initiate repair. They found that a component that promotes clotting -- von Willebrand factor (vWF) -- increases and remains elevated for hours after a single exposure to cocaine.

They also found that heavy users of cocaine have elevated levels of vWF, fibrinogen (a clotting factor), and C-reactive protein (CRP), a blood protein that increases in concentration in response to inflammation and is a reliable indicator of risk for heart attack.

Inflammation in the Cardiovascular System

"These findings suggest that cocaine creates a temporary risk for heart attack or stroke by increasing clotting factors," Dr. Siegel explains.

"Elevated CRP levels could indicate that long-term use of the drug is triggering inflammation in the cardiovascular system."

Researchers used 20 subjects (10 women and 10 men, average age 26 years) who used cocaine two to six times per month but were drug-free at the time of the study. They received injections of low (0.2 mg/kg) or moderate (0.4 mg/kg) doses of cocaine or of saline solution. Their clotting-related blood components were recorded every 30 minutes for 4 hours.

For those who received moderate doses of cocaine levels of vWF increased by approximately 40 percent and remained elevated for four hours. The same was not true for those receiving low-dose cocaine or saline,

No Protective Factors With Cocaine

"With healthy subjects, it's not unusual to see a temporary increase in vWF after normal activity such as exercise," Dr. Siegel says. "But the increase is balanced by higher levels of factors that control clotting. The increases that followed cocaine administration were not accompanied by compensatory increases in protective factors."

Following the original experiment, the Massachusetts compared the blood factor levels of the original study participants to those of 10 other individuals (6 women, 4 men, average age 41 years) who used the drug far more heavily - 6 to 20 times per week, on average - when both groups were drug-free. The heavy cocaine users had higher levels of vWF, fibrinogen, and CRP.

Cumulative Risk for Heart Attack and Stroke

"Elevated levels of CRP and clotting factors that we see in the heavy users suggest that repeated use of cocaine poses an exposure-related and cumulative risk for heart attack or stroke," Dr. Siegel said. "The fact that neither group showed any compensatory increase in anticlotting mechanisms suggests that cocaine use upsets the body's ability to maintain a balance between risk and protective factors and tips the scale toward increased risk of heart attack or stroke."

"Other factors certainly play a role in CRP levels, and cocaine alone is probably not responsible for the elevated levels we found," Siegel said. "For example, age is a factor but does not account for all of the difference. Smoking also may be a factor. In our study, cocaine users who smoked had higher CRP levels than those who did not. On the whole, these findings suggest that cocaine compounds the effects of other risk factors."

Sources:

Mittleman, MA, et al. "Triggering of Myocardial Infarction by Cocaine." Circulation Accessed 2015

National Institute on Drug Abuse. "Cocaine's Effect on Blood Components May Be Linked to Heart Attack and Stroke," NIDA Notes March 2003

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