Lipomatous hypertrophy of the interatrial septum: a distinct adipose tissue type in COPD?

Objective Lipomatous hypertrophy of the interatrial septum (LHIS) is a distinct compartment of epicardial adipose tissue (EAT). However, its association with chronic obstructive pulmonary disease (COPD) is poorly documented.

Methods Patients undergoing coronary CT angiography (CTA) for clinical indications were recruited retrospectively and screened for LHIS and COPD. LHIS density and the coronary artery disease profile were quantified by CTA: Stenosis severity (CADRADS), coronary artery calcium (CAC), and high-risk plaque (HRP). COPD patients with LHIS were matched for age and gender, the major (cardiovascular risk factors) CVRFs, and compared to controls.

Results The prevalence of LHIS in all 5466 patients was 5.9%. 151 (72.6%) of 208 patients with COPD had LHIS. LHIS density in COPD patients was higher (−10.93HU versus −21.1HU;p<0.001), despite BMI (28.8 versus 27.01 kg·m⁻²;p=0.002) was lower. LHIS-density was lower in obese (BMI>30 kg·m⁻²)(20.4 versus 13.6HU;p=0.02). BMI was inversely correlated with LHIS density (BetaR −0.031;95%CI:-0.054 - −0.008;p=0.007). LHIS-density was associated with COPD, but not with BMI on multivariate models. CAC and coronary stenosis severity (CADRADS and >50% stenosis) were not different (p=0.106; p=0.156 and p=0.350). High-risk plaques were observed more frequently in COPD patients with severe GOLD stages>=2 (32.3% versus 20.1%;p=0.044), but not when adding mild GOLD stages.

Conclusions The prevalence of LHIS in COPD patients is high (72.6%), and the adipose tissue density is higher, indicating a higher brown fat component. In obese, LHIS density is lower and declining along with BMI. Coronary stenosis severity and calcium were not different, however HRP were more frequent in severe COPD.

Translational outlook Further research is required to explore LHIS as imaging biomarker of epicardial adipose tissue (EAT) and its association with COPD and other clinical outcomes.