Influence of bronchial blood flow and conductance on pulmonary function in stable systolic heart failure

Background: The aim of this study was to determine the relationship between airway blood flow ((Q) over dot(aw)), airway conductance (G(f-aw)) and pulmonary function in patients with stable HF. Methods: 12 controls (CTRL: age = 63 +/- 9 years, FVC = 98 +/- 15%pred, LVEF = 61 +/- 6%) (all data presented as mean +/- SD), 16 patients with mild HF (HF-A, NYHA I-II: age = 64 +/- 9 years, FVC = 90 +/- 17% pred. LVEF=28 +/- 6%), and 14 patients with moderate/severe HF (HF-B, NYHA age = 65 6 years, FVC = 84 +/- 12%pred, LVEF = 26 +/- 6%) were studied. (Q) over dot(aw) was assessed using soluble gas measurements; perfusion pressure across airway bed (Paw) was estimated from systemic and pulmonary pressure measurements: G(f-aw) was calculated as (Q) over dot(aw)/Delta P-aw; PF was assessed by spirometry. Results: While (Q) over dot(aw), was not significantly different between CTRL (61.3 +/- 17.9 mu L min(-1) mL(-1)), HF-A (70.1 +/- 26.9 mu L min(-1) mL(-1)) and HF-B (56.2 +/- 14.9 mu min(-1) mL-1) groups, G(f-aw) was elevated in HF-A (1.1 +/- 0.4 0 mu Lmin(-1)L min(-1) mmHg(-1). p<0.03) and tended to be elevated in HF-B (1.2 +/- 0.6 mu L min(-1) mL(-1) mmHg(-1) , p = 0.07) when compared to CTRL (0.8 +/- 0.3 mu L min(-1) mL(-1) mmHg(-1)). Significant positive correlations were found between G(f-aw) and RV/TLC for HF-A (r=0.63, p<0.02) and HF-B (r=0.58, p<0.05). Conclusions: These results support the hypothesis that increased bronchial conductance and bronchial congestion may be related to greater small airway obstruction and as such may play a role in the PF abnormalities and symptoms of congestion commonly observed in HF patients. (C) 2011 Elsevier B.V. All rights reserved.