Does the bronchial circulation contribute to congestion in heart failure?

Abstract

Summary Pulmonary congestion is a hallmark feature of heart failure and is a major reason for hospital admissions in this patient population. Heart failure patients often demonstrate restrictive and obstructive pulmonary function abnormalities; however, the mechanisms of these functional declines remain controversial. It has been suggested that the bronchial circulation may play an important role in the development of these pulmonary abnormalities and in the symptoms associated with pulmonary congestion. Congestion may occur in the bronchial circulation from either a marked increase in flow or an increase in blood volume but with a reduction in flow due to high cardiac filling pressures and/or high pulmonary vascular pressures (a stasis like condition). Either may lead to thickened bronchial mucosal and submucosal tissues and reduced airway compliance resulting in airway obstruction and restriction and a lack of airway distensibility. These structural changes may contribute to “cardiac asthma” and dyspnea, characteristic features common in HF patients. Thus the bronchial circulation may be a potential target for therapeutic interventions. The aim of this paper is to review factors governing the control of the bronchial circulation, how bronchial vascular conductance may change with HF and to pose arguments, both supporting and in opposition to the bronchial circulation contributing to congestion and altered pulmonary function in HF. We ultimately hypothesize that the engorgement of the bronchial circulatory bed may play a role in pulmonary function abnormalities that occur in HF patients and contribute to symptoms such as orthopnea and exertional dyspnea.

Impact of chronic systolic heart failure on lung structure-function relationships in large airways

“…; Ceridon et al. ). Previous work has suggested a relationship between the airway luminal area of large to medium‐sized bronchioles and FEV 1 in healthy individuals; however, the relationship between structural changes and function in the HF population remains unclear (Coxson et al.…”

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

“…We have previously hypothesized that small changes in the caliber of airway mucosal vasculature could alter the morphometry of compliant distal airways, displacing tissue towards the adjacent lumen airspace and explain in part, the combined obstructive/restrictive and increased airway resistance seen in HF (Ceridon et al 2009). This engorgement of the bronchial mucosal and change in airway caliber may occur because the bronchioles are highly vascularized and the bronchial circulation lies near the airway lumen surface.…”

Influence of lung volume, fluid and capillary recruitment during positional changes and exercise on thoracic impedance in heart failure

“…However, impedance simply measures resistance between two points and whether or not this reflects actual changes in extravascular lung water remains speculative. In fact, pulmonary congestion itself remains poorly defined and can include changes in extravascular lung water, engorgement of the larger pulmonary vessels, the compliant pulmonary capillaries, the bronchial circulation or changes in all of these vascular and fluid beds (Olson et al, 2007; Ceridon et al, 2009). In addition, changes in lung volume can also significantly impact the impedance measure.…”