Pulmonary vascular pruning in smokers with bronchiectasis

There are few studies looking at the pulmonary circulation in subjects with bronchiectasis. We aimed to evaluate the intraparenchymal pulmonary vascular structure, using noncontrast chest computed tomography (CT), and its clinical implications in smokers with radiographic bronchiectasis.

Visual bronchiectasis scoring and quantitative assessment of the intraparenchymal pulmonary vasculature were performed on CT scans from 486 smokers. Clinical, lung function and 6-min walk test (6MWT) data were also collected. The ratio of blood vessel volume in vessels <5 mm² in cross-section (BV5) to total blood vessel volume (TBV) was used as measure of vascular pruning, with lower values indicating more pruning. Whole-lung and lobar BV5/TBV values were determined, and regression analyses were used to assess the differences in BV5/TBV between subjects with and without bronchiectasis.

155 (31.9%) smokers had bronchiectasis, which was, on average, mild in severity. Compared to subjects without bronchiectasis, those with lower-lobe bronchiectasis had greater vascular pruning in adjusted models. Among subjects with bronchiectasis, those with vascular pruning had lower forced expiratory volume in 1 s and 6MWT distance compared to those without vascular pruning.

Smokers with mild radiographic bronchiectasis appear to have pruning of the distal pulmonary vasculature and this pruning is associated with measures of disease severity.

Smokers with radiographic bronchiectasis haveintraparenchymal pulmonary vascular pruning, which is associated with both lung function and exercise capacity impairmenthttp://ow.ly/YCYm30mgV7z

Right ventriculo-arterial uncoupling and impaired contractile reserve in obese patients with unexplained exercise intolerance

Background

Right ventricular (RV) dysfunction and heart failure with preserved ejection fraction may contribute to exercise intolerance in obesity. To further define RV exercise responses, we investigated RV–arterial coupling in obesity with and without development of exercise pulmonary venous hypertension (ePVH).

Methods

RV–arterial coupling defined as RV end-systolic elastance/pulmonary artery elastance (Ees/Ea) was calculated from invasive cardiopulmonary exercise test data in 6 controls, 8 obese patients without ePVH (Obese−ePVH) and 8 obese patients with ePVH (Obese+ePVH) within a larger series. ePVH was defined as a resting pulmonary arterial wedge pressure < 15 mmHg but ≥ 20 mmHg on exercise. Exercise haemodynamics were further evaluated in 18 controls, 20 Obese−ePVH and 17 Obese+ePVH patients.

Results

Both Obese−ePVH and Obese+ePVH groups developed exercise RV–arterial uncoupling (peak Ees/Ea = 1.45 ± 0.26 vs 0.67 ± 0.18 vs 0.56 ± 0.11, p < 0.001, controls vs Obese−ePVH vs Obese+ePVH respectively) with higher peak afterload (peak Ea = 0.31 ± 0.07 vs 0.75 ± 0.32 vs 0.88 ± 0.62 mL/mmHg, p = 0.043) and similar peak contractility (peak Ees = 0.50 ± 0.16 vs 0.45 ± 0.22 vs 0.48 ± 0.17 mL/mmHg, p = 0.89). RV contractile reserve was highest in controls (ΔEes = 224 ± 80 vs 154 ± 39 vs 141 ± 34% of baseline respectively, p < 0.001). Peak Ees/Ea correlated with peak pulmonary vascular compliance (PVC, r = 0.53, p = 0.02) but not peak pulmonary vascular resistance (PVR, r = − 0.20, p = 0.46). In the larger cohort, Obese+ePVH patients on exercise demonstrated higher right atrial pressure, lower cardiac output and steeper pressure-flow responses. BMI correlated with peak PVC (r = − 0.35, p = 0.04) but not with peak PVR (r = 0.24, p = 0.25).

Conclusions

Exercise RV–arterial uncoupling and reduced RV contractile reserve further characterise obesity-related exercise intolerance. RV dysfunction in obesity may develop independent of exercise LV filling pressures.