What is the most likely cause of PAH in a patient with scleroderma and Sjögren syndrome?

In patients with scleroderma and Sjögren syndrome, the most likely cause of pulmonary arterial hypertension (PAH) is connective tissue disease. Both scleroderma and Sjögren syndrome fall under the category of autoimmune connective tissue diseases, which can lead to various complications, including changes in vascular structure and function.

In the context of these diseases, PAH is often a result of vascular remodeling, inflammation, and fibrosis, which can occur in the pulmonary vasculature. The interaction between the immune system and vascular endothelium plays a significant role in the development of PAH in these patients. This reflects a common pathophysiological mechanism associated with connective tissue disorders, leading to elevated pulmonary arterial pressures due to both structural and functional alterations in the pulmonary circulation.

While coronary artery disease, idiopathic factors, and chronic kidney disease can contribute to PAH in other contexts, in the setting of scleroderma and Sjögren syndrome, the underlying connective tissue disease provides a clearer and more direct association with the development of pulmonary arterial hypertension. Thus, this choice accurately identifies the principal etiology in this specific patient population.