Chronic Pulmonary Thromboembolism :  The operation recommended is pulmonary thrombo endarterectomy.

Indication :  The main indication for surgery is when patients with chronic hromboembolism have ventilatory or haemodynamic impairment at rest or exercise. Patients with obstruction of only one pulmonary artery should also be considered for operation if they are physically very active and they reside at high altitudes. Patients, who are symptomatic but have near normal haemodynarnics at rest but develop severe pulmonary hypertension on exercise, should also have surgery. For successful surgery the clots should be in branch, lobar or proximal segmental arteries. If the blocks are beyond that, it should be considered inoperable.

Severe underlying obstructive or restrictive pullnonary disease, advanced age, severe light ventricular failure and co morbid conditions should be considered as contra indications.