Study examines cardiovascular risks detected by cardiac MRI

GLASGOW — Researchers here reported an increased incidence of late gadolinium enhancement detected on cardiac magnetic resonance imaging in asymptomatic HIV patients.

Aisling Loy, of St. James’s Hospital, Dublin, and colleagues conducted a prospective cohort study of 131 asymptomatic HIV-positive men taking ART and compared them with 33 age-matched controls. The researchers recorded baseline demographics, HIV parameters, 12-lead electrocardiogram, routine biochemistry and traditional cardiovascular risk factors. Cardiac images were acquired using a 3T Philips MRI scanner with 5-channel phased array cardiac coil and weight-based IV gadolinium given at 0.15 mmol/kg with post-contrast inversion recovery imaging after 10 minutes, according to an abstract.

“As we know, there is a higher incidence of CVD in HIV-positive people when compared to the general population, despite treatment with ART. Most studies to date have looked at actual cardiac events, hospitalizations or myocardial infarctions; very few studies have looked at very early stage CVD,” Loy said during her presentation at the HIV11 Congress. “The aim of this study was to determine the prevalence of unrecognized cardiac dysfunction and myocardial infarction.”

According to the results, six cases showed late gadolinium enhancement on cardiac MRI vs. 2.9% of the control group. Two distinct pathological processes were identified as causing these changes: MI and myocarditis. Two of the cases were in a pattern consistent with previous MI. Four of six cases had a pattern of myocarditis, according to Loy.

“The prevalence of previously undiagnosed MRI was 1.45% and the prevalence of undiagnosed myocarditis was 3%,” Loy said.

There were no significant differences in mean left ventricular ejection fraction (66.93% vs. 65.18%), left ventricular MI (60.05% g/m2 vs. 55.94 g/m2) or posterolateral wall thickness (8.28 mm vs. 8.16 mm) between HIV-positive men taking ART and controls, respectively.

HIV-positive also had a lower E:A ratio (18% vs. 7%; P=.037), a marker of early cardiac disease and diastolic function.

Anteroseptal wall thickness, another early marker of cardiac disease, was significantly greater in HIV-positive men compared with controls (P=.004).

More than 6% of the patient population was in the range of moderate to severe hypertrophy.

Traditional CV risk factors, such as Framingham risk score, did not predict the early CVD seen in this study. Further, these findings were independent of traditional cardiac risk factors, duration of HIV infection and ART therapy, Loy said.

The only significant risk factor was a slight difference in the smoking pack-year history. She said this may explain the slight difference between the cases and controls, but would not explain the myocarditis.

“The impact of these subtle changes in CV outcome is yet unknown, as this is a cross-sectional study and longitudinal follow-up would be required,” Loy said. - by Katie Kalvaitis

For more information:

Loy A. #P25. Presented at: HIV11 Congress; Nov. 11-15, 2012; Glasgow.

Disclosure: Abbott Virology External Collaborations funded the project.