TNF and pulmonary arterial hypertension: Inflammation is a prominent feature in the development of PAH, and elevated circulating levels of cytokines have been reported in patients with PAH, such as TNF-α, IL-1β, and IL-6.22, 23, 24 However, the authors did not detect increasing levels of TNF-α, IL-1β, and IL-6 in the preoperative PAH—CHD patients.