This is an open label, randomized, interventional study indented to find the efficacy of different treatment regimens in treatment of pulmonary hypertension secondary to lung disease and/or hypoxia.This is to find out when to start combination therapy (sildenafil plus bosentan) in treatment of pulmonary hypertension secondary to lung disease and/or hypoxia.

This is an open label, randomized, interventional study indented to find the efficacy of different treatment regimens in treatment of pulmonary hypertension secondary to lung disease and/or hypoxia. It involves 3 arms, one getting monotherapy with sildenafil for 6 months, 2nd getting bosentan monotherapy initially for 3 months and then combination of sildenafil and bosentan for 3 months, 3rd getting combination sildenafil and bosentan from the beginning for 6 months. The aim is to decide when is the best time to start combination therapy either from start or at the time of drug failure. Improvement will be assessed by change in functional class, pulmonary pressures measured by ECHO, pulmonary function test, six minute walk test and biochemical markers. Lack of randomized trials and Indian data is there on the subject. Also adverse events and serious adverse events will be closely monitored and reported to the ethics committee and DCGI immediately.

Inclusion Criteria:

1. Pulmonary artery hypertension diagnosed by doppler echocardiography as mean pulmonary artery pressure 25 mmHg (done in department of cardiology, AIIMS)
2. Age more than 18 years
3. Pulmonary artery hypertension due to hypoxia, either chronic obstructive airway disease or diffuse pulmonary lung disease
4. Willing to consent to participate in the trial
5. WHO functional class I,II, III

Exclusion Criteria:

1. WHO functional class IV
2. Patient participating in any other trial
3. Concomitant coronary artery disease
4. Nitrate intake
5. Liver dysfunction
6. Pregnancy and lactation -