Effect of Sildenafil Citrate on Pulmonary Arterial Systolic Pressure and Sub-maximal Exercise Capacity in Chronic Obstructive Pulmonary Disease.

Background Pulmonary hypertension (PH) often complicates Chronic Obstructive Pulmonary Disease (COPD). Sildenafil reduces pulmonary arterial pressure associated with multitude of diseases. Objective To evaluate the use of Sildenafil in Pulmonary Hypertension associated with COPD. Method This randomized control study enrolled 72 patients: 61 completed the study. Thirtypatients with COPD received Sildenafil 25 mg thrice daily and 31 patients with COPD received optimal medical therapy for four weeks. Symptom assessment and dyspnoea grading was done with modified Borg scale and Modified Medical Research Council (MMRC) grade. The functional assessment was done with WHO functional classification. The estimation of pulmonary arterial systolic pressure and six minute walking distance was done before and after four weeks of the administration of therapy in both groups. Adverse reaction profiling was done for Sildenafil. The primary outcomes were the changes in pulmonary arterial systolic pressure and six minute walk test. The secondary outcomes were change in modified Borg scale for dyspnoea, MMRC grading and WHO functional class. Result The mean decrease in pulmonary arterial systolic pressure in Sildenafil group was significant as compared to controls (9.87+7.84 mmHg Vs 5.93+7.44 mmHg, P=0.048). The mean increase in six minute walk distance was significantly more in cases as compared to controls (48.13+25.79 m Vs 32.59+32.96 m,P=0.047). The changes in modified Borg scale was not significant (1.20+1.92 to 1.55+1.23; P=0.401). There was significant changes in MMRC grade (p=0.037). There was no significant change in WHO functional class after four weeks (p=0.071). Conclusion Sildenafil marginally decreased pulmonary arterial systolic pressure and increased six minute walk distance in COPD patients. It improved MMRC grading without affecting modified Borg's Scale and WHO functional class.