CT Angiography Showed Higher Non-Calcified Plaque Burden in People with HIV

Individuals who are living with HIV – but who do not show signs of cardiovascular disease – actually have two-to-three times as much non-calcified coronary plaque as healthy individuals, according to new research.

HIV-positive patients are known to have a 1.5-to-2.1 higher risk of heart attack than the general population that does not carry the virus. But, data and findings about non-calcified coronary plaque have been controversial and unclear to-date.

Now, in a study published April 20 in Radiology, investigators from the Centre hospitalier de l’Université de Montréal have effectively shown that HIV is, in fact, associated with an increase in the prevalence of plaque and plaque burden. This knowledge is critical said the team, led by Carl Chartrand-Lefebvre, M.D., M.Sc., clinical professor, because modern advancements in anti-retroviral medications have changed the life expectancy for people living with the virus.

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“People with HIV infection now live longer and increasingly experience age-related diseases, such as coronary artery disease (CAD),” the team said, noting that the medications used in HIV management could contribute the disease burden.

To determine whether individuals living with HIV had different experiences with CAD and different CT characteristics of coronary plaque, Chartrand-Lefebvre’s teams conducted a prospective study with 265 participants – 181 people living with HIV and 84 healthy volunteers. The average age of patients living with HIV and healthy participants was 56 years and 57 years, respectively.

Non-calcified coronary plaque in an asymptomatic 52-year-old man living with HIV with a 10-year Framingham risk of 5 percent. Images show 256-section contrast-enhanced coronary CT angiography with electrocardiographic gating and curve reformat. A, B, CT scan shows a smooth non-calcified plaque in the right coronary artery (arrows) with 70 percent – 80 percent stenosis. C, D, The right coronary artery plaque volume was 130 mm3 (cyan lines).

More patients with HIV than healthy cohorts were tobacco smokers (30 percent and 11 percent respectively), and more patients with HIV were actively taking statin therapy (31 percent versus 18 percent, respectively). In addition, 92.3 percent of HIV-positive individuals had been receiving anti-retroviral therapy for an average of 13.6 years.

For the study, each participant underwent coronary CT angiography with a 256-section CT scanner and 370 mg/mL iopamidol at a 5 mL/sec rate. The team also performed a non-contrast CT for coronary calcium scoring. For analysis, interpreting radiologists were unaware of which patients were HIV-positive.

While their analysis revealed no difference between the coronary artery calcium score and overall plaque prevalence between both groups, the evaluation did showcase that the non-calcified plaque prevalence and volume visualized on CT angiography were two-to-three times higher in patients living with HIV after adjusting for cardiovascular risk factors.

“Our study shows that non-calcified coronary plaque is increased in people living with HIV,” Lefebvre said. “And, non-calcified plaque has previously been shown to be associated with worse cardiovascular outcome than calcified or mixed plaques.”

In addition, the team discovered that patients with HIV had a 40-percent reduced calcified plaque frequency. While the difference in frequency between groups can likely be attributed to a variety of factors, they highlighted the use of anti-retroviral therapy as a likely significant contributor.

“Multiple studies suggest that there is probably an impact of antiretroviral therapy that could increase the risk of coronary artery disease, although there are far more advantage for people living with HIV to be on anti-retroviral therapy, instead of not taking it,” they said.

According to Shenghan Lai, M.D., MPH, a professor in the epidemiology department and the Institute of Human Virology at the University of Maryland School of Medicine, this study outperforms other existing studies that examined coronary artery disease in patients with HIV. In an accompanying editorial, he explained that the use of volume to quantify plaque burden can provide a more complete representation of the plaque.

“This study for the first time demonstrated that HIV infection is associated with increase in the prevalence of plaque and of plaque volume, and that the latter conclusion is based on a more accurate characterization of plaque burden than some other prior methods,” he said. “Coronary CT angiography should be considered the non-invasive imaging option of choice in further clinical, prognostic, and mechanistic studies of HIV-associated atherosclerosis.”

Chartrand-Lefebvre’s team agreed, adding that their results indicate a healthier lifestyle that can combat atherosclerosis is particularly critical for patients living with HIV. It is imperative, the team stressed, that is patient group be aware of the added risks associated with smoking, diabetes, high blood pressure, obesity, and the lack of exercise.

In addition, they said, the results also inform how radiologists can use these scans.

“For radiologists, these results suggest that coronary CT angiography interpretation in people living with HIV should probably include quantification of coronary plaque by subtypes to allow better cardiovascular risk stratification,” Chartrand-Lefebvre said.

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