Cardiovascular Magnetic Resonance in patients with HIV Infection : assessing the structural and functional abnormalities associated with remodelling of the myocardium

Abstract

Background: The pandemic of human immunodeficiency virus (HIV) infection in sub-Saharan Africa with its attendant dire impact on society and the economy continues. In 2016 it was estimated that the disease affected 36.7 million (30.8–42.9 million) people worldwide, with the majority living in Sub- Saharan Africa (7.1 million in South Africa). South Africa spent over 1 billion US dollars on the disease in 2014. In the pre-antiretroviral therapy (ART) era, once the myocardium was involved, life expectancy seriously declined and was estimated at less than 6 months. The widespread availability of ART profoundly altered the epidemiology, natural history and outcomes of HIV-associated cardiovascular disease (CVD). The functional, structural and tissue characteristics of the cardiovascular manifestations of HIV infection can be assessed with accuracy using cardiovascular magnetic resonance (CMR). This study was designed to ascertain the effects of HIV on the myocardium in untreated asymptomatic young patients, at a time when the national policy in South Africa (SA) was to prescribe ART only to HIVinfected patients with a CD4+ count below 350 cells/mm3. Methods and results: Systolic and diastolic functional parameters as well as structural and tissue characteristics were assessed using a single 1.5 Tesla magnet in 40 asymptomatic untreated young HIVinfected patients from Tshwane district, South Africa (median age 36±10 years, 78% female), who presented for the first time and the findings compared to 37 healthy controls (matched for age and sex with a median age 36±11 years, 70% female). Left ventricular volumes, mass and ejection fraction did not differ significantly between the two groups (59±21% in HIV infected versus 61±29% in controls, p=0.7). However, there was a significant difference in the strain rate assessment (peak systolic circumferential strain rate in the HIV- infected group was -1.2±0.56 s-1 versus -0.1±0.22 s-1 in controls, p=0.044; peak systolic longitudinal strain rate in the HIV-infected group was -1.0±0.23 s-1 versus -0.8±0.43 s-1 in controls, p=0.014 and peak systolic radial strain rate was 2.2±0.67 s-1 in the HIV-infected group versus 1.8±0.55 s-1 in the controls, p=0.004). Native T1 times were significantly higher in the HIV-infected patients (1085 ms versus 1052 ms in controls, p=0.037). There was no difference in the presence of myocardial oedema between the groups (1.95 versus 2.14 in the control group, p=0.082). There was increased late gadolinium enhancement of the myocardium present in the HIV-infected patients (83.8% versus 48.6% in controls, p= 0.002). Conclusions: HIV infection is associated with strain abnormalities, and focal myocardial fibrosis in asymptomatic, untreated, young patients, unlikely to have been affected by other risk factors for cardiovascular disease, early in the course of the disease.