COMPARISON OF BRONCHOPULMONARY COLLATERALS AND COLLATERAL BLOOD-FLOW IN PATIENTS WITH CHRONIC THROMBOEMBOLIC AND PRIMARY PULMONARY-HYPERTENSION

Objective-To compare the visualisation of bronchopulnonary collaterals and bronchopulmonary collateral blood how in patients with chronic th romboembolic pulmonary hypertension and primary pulmonary hypertension . Setting-Referral centre for cardiology at an academic hospital. Pati ents-Nine patients with chronic thromboembolic pulmonary hypertension and 17 with primary pulmonary hypertension. Interventions-Bronchopulmo nary collaterals were visualised by selective bronchial arteriography or thoracic aortography. Bronchopulmonary collateral blood flow was es timated by injecting indocyanine green into the ascending aorta and sa mpling below the mitral valve from the left ventricle. Results-The deg ree of pulmonary hypertension was comparable in the two groups. Large bronchopulmonary collaterals were visualised in all the patients with thromboembolic pulmonary hypertension who had bronchial arteriography or aortography or both. None of the primary pulmonary hypertension gro up studied by aortography had bronchopulmonary collaterals (P << 0.001 ). All the patients with chronic thromboembolic pulmonary hypertension had significant bronchopulmonary collateral blood flow, which was (me an (SD)) 29.8 (18.6)% of the systemic blood flow. There was no recorda ble collateral blood flow in 11 of 15 patients with primary pulmonary hypertension. In the remaining four patients the mean value was 1.1 (1 .8)% of the systemic blood flow (P << 0.001). Conclusions-Visualisatio n of bronchopulmonary collaterals by thoracic aortography or by bronch ial arteriography, or the demonstration of an increased bronchopulmona ry collateral flow, helps to distinguish patients with chronic thrombo embolic pulmonary hypertension from those with primary pulmonary hyper tension.