[Lung function and exercise tolerance in patients with chronic major vessel thromboembolic pulmonary hypertension]

We studied 14 consecutive patients with severe pulmonary hypertension due to chronic major vessel thromboembolic pulmonary hypertension (CPTEH), clinical entity that may be successfully surgically treated by pulmonary thrombendarterectomy. Resting pulmonary mechanics and gas exchange were investigated. Exercise tolerance was studied by 3 different exercise tests. Pulmonary volumes and flows were normal. Some patients presented with decreased lung compliance and reduced diffusion capacity for carbon monoxide. Majority of patients had hypoxaemia and respiratory alkalosis. Exercise tolerance was very limited. In 6 minute walking test patients covered 346 +/- 95 meters. During Bruce test patients completed from 1 to 4 stages. During incremental maximal symptom limited test on cycloergometer patients achieved 56 +/- 18 watts. We concluded that patients with CPTEH present with resting hypoxaemia deteriorating further on exercise and severely limited exercise tolerance.