Cocaine use confers epicardial, microvascular disease
Patients with a history of long-term cocaine use have higher rates of coronary endothelial dysfunction, which may increase catecholamine sensitivity resulting in epicardial and microvascular disease, according to a research letter published in the Journal of the American College of Cardiology.
According to the study, among illicit drugs, cocaine is responsible for the highest number of ED visits and hospitalizations and continues to grow in urban settings.
“We work in a safety net hospital which serves low income and not well-educated patients. We see many young patients presenting with chest pain after they [use cocaine],” Varun Kumar, MD, from the department of cardiovascular medicine at Mount Sinai Hospital Medical Center, Chicago, told Cardiology Today. “When we find no significant blockages on angiogram, they have a false sense of well-being that cocaine did not harm them and may continue to abuse the drug. To understand the cause of chest pain and possible reason for positive stress test, we did this study to look beyond epicardial coronary arteries.”
Cocaine users may demonstrate normal epicardial coronaries on angiography, but they may experience continued angina as a result of coronary microvascular dysfunction, the researchers hypothesized.
Because cocaine use is both symptathomimetic and prothrombotic, myocardial oxygen demand is increased and oxygen supply is decreased by the use of the drug, potentially resulting in myocardial ischemia, Kumar and colleagues wrote.
To address the knowledge gap in the effects of chronic cocaine use on microvasculature, Kumar and colleagues conducted a retrospective study of 202 eligible cocaine users who underwent angiography at a single center between 2005 and 2013. Patients were included in the study if they were absent of acute or recent MI and significant CAD.
A second group of patients (n = 210) who were not cocaine users and underwent coronary angiography were also selected for the study.
Corrected TIMI frame count and TIMI perfusion grade for the left anterior descending artery, the left circumflex artery and the right coronary artery were analyzed by two blinded angiographers.
The researchers found that data on corrected TIMI frame count and TIMI perfusion grade suggested that coronary microvascular dysfunction was much greater among cocaine users compared with nonusers.
A TIMI perfusion grade of 0 or 1 was more common in cocaine users vs. nonusers for all three arteries (P < .0001 for all).
Among patients in the cocaine group, corrected TIMI frame count was significantly higher in the left anterior descending (P = .026) and left circumflex artery (P = .0362), suggesting slow flow through normal epicardial coronaries, possibly due to increased microvascular resistance, Kumar and colleagues wrote.
There was a significantly greater number of patients with hyperemic flow (corrected TIMI frame count < 14) in the right coronary artery among cocaine users vs. nonusers (P = .0079).
“This study will throw light on importance of assessing for coronary microvasculature and that normal epicardial coronaries is not the end of it,” Kumar said. “These cocaine patients with microvascular disease may need to be on antiplatelets in addition to stopping cocaine. Medical management with antiplatelets in these patients needs to be studied further.” – by Dave Quaile
Disclosure: The authors report no relevant financial disclosures.