Background: There is limited and conflicting evidence for the use of targeted pulmonary arterial hypertension (PAH) therapy in patients with pulmonary hypertension (PH) associated with respiratory disease. In addition, there is concern that these drugs may have a deleterious effect on gas exchange due to the inhibition of hypoxic vasoconstriction in this population. Accordingly, we conducted a systematic review of the effects of targeted PAH therapy on arterial oxygenation in patients with PH associated with lung disease.

Methods: The search was performed in five databases. Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of the evidence. 

Results: 11 studies were included (n=872, 62% male), reported effects on arterial oxygenation at the end of the trial. 7 studies were conducted in patients with COPD and 4 in patients with ILD. Age varied between 55±9 and 70±7 years. Mean pulmonary artery pressure ranged 27±3 to 39±8 mmHg; cardiac index 2.2±0.5 to 2.9±0.7, and pulmonary vascular resistance 4.6±2.7 to 7.4±4.0 WU. The partial pressure of arterial oxygen (PaO2) at the end of the trial (6 studies) in the intervention group (IG), treated with targeted PAH therapy, was similar to the CG (MD 0.3 mmHg; 95%CI -2.9,3.5 mmHg; p=0.85)(Figure 1). In 4 studies reporting resting peripheral oxygen saturation (SpO2) at the end of the trial, it was similar in the IG and CG (MD ?0.1%; 95%CI -0.9%,0.6%; p=0.70) (Figure 2).

Conclusion: Targeted PAH therapy in patients with PH associated with lung disease does not impair arterial oxygenation in the long term.