Epicardial adipose tissue in HIV-infected patients

Abstract

We read with interest the letter that intended to clarify a few important points regarding our recent publication in AIDS. It is true that a number of our patients did not have coronary artery calcium (CAC), although please note the two following points: ours was a population of young patients, and the development of CAC is age dependent (besides being influenced by other cardiovascular risk factors). Additionally, although CAC is a good marker of atherosclerosis, it is usually detected in more advanced stages of disease; the absence of CAC does not exclude that noncalcified and more friable plaque may already be present. In fact, Lo et al.[1] reported a higher than expected prevalence of noncalcified plaque by computed tomography angiography in HIV-infected patients. Hence, we believe that our observation that epicardial adipose tissue (EAT) is associated with a high-risk CAC score remains valid despite the low prevalence of CAC. It is further suggested that EAT may be a better marker of risk for cardiovascular disease in the presence of lipodystrophy. The type of visceral fat found in EAT and visceral adipose tissue (VAT) is considered highly inflammatory and potentially involved in atherosclerosis development, although a recent metanalysis questioned the association of VAT with coronary artery disease [2]. Although there was a correlation between EAT and VAT in our study, the association was weak. This was confirmed in a properly designed study recently presented at the 13th International Workshop on adverse drug reaction and comorbidities in HIV [3]. In fact, it is not rare to find small amounts of EAT in some obese individuals and considerably more EAT in some lean individuals. Of note, EAT was predictive of incident cardiovascular events independent of conventional risk factors and BMI in the Multi Ethnic Study of Atherosclerosis [4] and another observational study [5]. Finally, in a prior publication, we described a close association between hypertrophic and mixed type lipodystrophy and CAC [6]. Therefore, we feel that EAT may be a predictor of risk independent of the presence of highly active antiretroviral therapy-induced lipodystrophy. Acknowledgement Conflicts of interest The authors have no conflict of interest.