ANGIOGENESIS IN BRONCHIAL CIRCULATORY-SYSTEM AFTER UNILATERAL PULMONARY-ARTERY OBSTRUCTION

We studied the effects of left pulmonary artery (LPA) ligation on the bronchial circulatory system (BCS) by using a sheep model. LPA was lig ated in tile newborn lambs soon after birth (n = 8), and when the shee p were similar to 3 yr of age anatomic studies revealed marked angioge nesis in BCS. Bronchial blood flow and cardiac output were studied by placing flow probes around the bronchial and pulmonary arteries in fou r adult sheep. After LPA ligation, bronchial blood flow increased from 35 +/- 6 to 134 +/- 42 ml/min in similar to 3 wk (P < 0.05). We also studied gas-exchange functions of BCS similar to 3 yr after the ligati on of LPA in newborn lambs (n = 4) and used a control group (n = 12) i n which LPA was ligated acutely. In the left lung, O-2 uptake after ac ute ligation was 16 +/- 3 ml/min and was similar to the chronic model, whereas CO2 output in the control group was 27 +/- 3 ml/min compared with 79 +/- 12 ml/min in the chronic preparation (P < 0.05). We conclu de that LPA ligation causes marked angiogenesis in BCS that is capable of performing some gas-exchange functions.