Abstract
Rationale: Along with reduced gas lung volumes, pulmonary gas exchange in severe obesity could be altered by inflammation and direct effects of perivascular adipose tissue (PVAT) in the pulmonary vasculature. Since both effects could be reflected by elevatedlung tissue volume(Vtiss), we asked whether Vtiss was reduced by bariatric surgery (BS).
Methods: Using densitometry on HRCT scans, we estimated Vtiss in 12 severe obese women before and one year after BS. These findings were compared to those of 8 lean healthy women, age-matched. Vtiss was defined as the total volume of the lung not occupied by air or large bronchi and vessels. For comparisons between subjects, Vtiss was standardized by the subject's body height. Serum inflammatory markers were also measured.
Results: Pre-operatively, as compared with controls, Vtiss, body mass index (BMI) and serum biomarkers (serum C-reactive protein, fibrinogen and leptin) were all increased and were significantly diminished after BS. Vtiss was systematically reduced (by 9%) without affecting other CT lung volumes. No relationship was observed between BS-induced changes in Vtiss and those in pulmonary vessel area.
Conclusions: Vtiss is increased in obese compared to lean individuals and decreased systematically by BS. These effects do not appear to be related to changes in the area of blood vessels. Instead, they could be consistent with a potential elevation of extra-vascular lung water, due to low-grade inflammation and/or hypertrophic PVAT in pulmonary small vessels and/or capillary.
- Copyright ©the authors 2016
