Introduction

Different parts of the pulmonary vasculature can be affected or involved during the course of a variety of lung diseases, for example, small pulmonary arteries show frequently in situ thrombosis and the capillary endothelium is leaky in the lungs of patients with the adult respiratory distress syndrome (ARDS). The pulmonary vasculature is certainly involved and structurally altered in COPD and emphysema. There is pulmonary vascular involvement in eosinophilic granulomatosis, and it is often overlooked that there is significant vascular involvement in many forms of interstitial fibrosis, as well as in collagen vascular disorders. Table 19.1 gives a list of lung diseases with pulmonary vascular involvement.

Pulmonary vascular remodelling is also a prominent feature of mitral valve stenosis, chronic left ventricular dysfunction, kyphoscoliosis and sleep apnea syndromes.

The recommendation for treatment of the pulmonary vascular disease component in these conditions has been and continues to be to treat the underlying primary lung disease. Unfortunately, some of the disorders that are associated with pulmonary hypertension or pulmonary vascular abnormalities are difficult to treat, for example interstitial lung diseases (ILD) or ARDS. On the other hand, treatment of patients with COPD with supplemental continuous oxygen has been shown to improve pulmonary hypertension (PH) and patient survival yet it is not at all clear whether the patient survival is causally related to a reduced pulmonary arterial pressure.