HIV infection, viral load and injecting drug use linked to early signs of cardiovascular disease

HIV-positive patients have signs of damage to the lining of blood vessels, according to a study published in the 1st May edition of Clinical Infectious Diseases. The study found that blood vessel damage was more pronounced in the patients who had higher viral loads, particularly injection drug users. Reduced flexibility of blood vessels in response to blood flow is the earliest detectable sign of the development of cardiovascular disease. This reduced flexibility, called ‘endothelial dysfunction’, is caused by the failure of cells lining blood vessels to stimulate the vessels to widen when blood flow increases.

Several studies have suggested that HIV-positive patients receiving antiretroviral therapy, particularly protease inhibitors, may be at risk of developing heart disease or strokes. To assess the effects of HIV infection and its treatment on endothelial function, investigators used ultrasound scans to measure the responses of a large artery in the arm in 75 HIV-positive patients from the Boston Medical Center Infectious Disease Clinic. After constricting the blood flow through the arm with a blood pressure cuff for five minutes, the investigators measured the dilation of the brachial artery and blood flow after the cuff had been removed. They found that the dilation of the artery in the patients was significantly lower than in a group of 223 control patients from the same clinic (mean 7.3 vs. 11.1%, p < 0.001). The difference between the two groups was similar when they adjusted the measurement for smoking, sex and body mass index (BMI), a measurement of body weight relative to height (p < 0.01). Being a smoker, being male and having a BMI above 30 kg/m2 were also independently linked to impaired endothelial function.

“The present study showed a strong association between HIV-1 infection and endothelial dysfunction,” write the investigators. “This finding is consistent with several studies that have described the association of coronary artery disease with HIV infection.” Using a multivariate analysis, the investigators found that current injection drug use had a significant association with artery dilation in the HIV-positive patients (p = 0.007). Fifteen (20%) of the patients were current intravenous drug users, with seven using heroin, three using cocaine and five using both drugs. The researchers noted that when they did not include injecting drug use in their calculations, HIV viral load emerged as being significantly associated with endothelial dysfunction (p = 0.04). This demonstrates that the effects of intravenous read more