Comparison of Long Term Oxygen-Therapy (LTOT) and LTOT Combined with Sildenafil and Simvastatin in the Treatment of Severe Chronic Obstructive Pulmonary (COPD) with Hypoxia at Rest and Severe Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension is frequent in patients with severe chronic obstructive pulmonary disease (COPD). It increases the morbidity and mortality of patients with advanced stage of COPD. The use of long-term oxygen therapy (LTOT) and some other vasodilators seems necessary to prevent pulmonary arterial hypertension (PAH) and right heart failure in these patients. Objective: This study was planned to compare the effect of LTOT alone and LTOT combined with sildenafil (PDE-5 inhibitor) and simvastatin (HMG CoA reductase inhibitor) on pulmonary arterial pressure of patients with severe COPD having hypoxia at rest. Methods: It was a cross-sectional and comparative study. All patients with severe COPD having hypoxia at rest (SpO2<88%) had been classified in three groups: Group 1 (treated with LTOT), Group 2 (treated with LTOT+sildenafil), and Group 3 (treated with LTOT+sildenafil+simvastatin). All study patients had been treated with conventional therapy (long-acting beta2-agonists+inhaled corticosteroids+long-acting muscarinic antagonists) and followed up during 6 months with one visit every three months. The mean systolic pulmonary arterial pressures (PAP) had been measured by transthoracic echocardiography (TTE). Results: Ninety-eight patients with severe COPD and hypoxia at rest were included in this study (Group 1:32 patients, Group 2:35 patients, and Group 3:31 patients). The systolic PAPs and diffusing capacity of the lungs for carbon monoxide (DLCO) were significantly ameliorated after 3 to 6 months. The mean systolic PAP in patients from Group 2 and Group 3 were significantly lower than that in Group 1 at 3 months (41 ± 9 mmHg and 39 ± 7 mmHg vs. 46 ± 10 mmHg; P<0.05 and P<0.05; respectively). After 6 months, oxygen consumption (VO2 max) and 6 minutes walking distances were significantly increased in patients from Group 2 and Group 3 (P<0.05 and P<0.05; respectively). Conclusion: LTOT is an efficacy treatment for severe COPD patients with hypoxia at rest and PAH. Sildenafil and simvastatin have some additional effect on the reduction of PAP and physical exercise capacity.