Chronic thrombotic obstruction of major pulmonary arteries. Results of thromboendarterectomy in 15 patients.

Since 1969, 15 patients, ranging in age from 21 to 67 years, with pulmonary hypertension associated with chronic thrombotic obstruction of major pulmonary arteries have had pulmonary thromboendarterectomy. Symptoms compatible with embolism antedated surgery for periods of 8 months to 18 years; several alternative diagnoses were maintained for months to years. Only 2 of 15 were treated for the initial embolic episode. All patients had dyspnea on exertion and were in New York Heart Association class III-IV before surgery. Resting arterial hypoxemia was common. Resting preoperative mean pulmonary artery pressures ranged from 25 to 66 mm Hg; pulmonary vascular resistances, 420 to 1869 dynes/sec X cm-5. Partial or complete thromboendarterectomy was possible in patients using cardiopulmonary bypass with hypothermia and cardioplegia. All patients showed a fall in pulmonary vascular resistance. All developed some degree of "reperfusion" lung edema and arterial hypoxemia that lasted for a few days to several months. Two patients died during hospitalization. The 13 survivors have been followed for 8 to 144 months (mean, 38.3 months). All patients improved after surgery. One patient died of nonembolic causes; none had recurrent embolism.