While the effect of VEGFR inhibition on the development or progression of PTTM is unknown, there is experimental evidence that exposure to a single dose of a VEGFR inhibitor, semaxanib (SU-5416), followed by chronic hypoxia leads to angioobliterative PAH in rats that mimics the histopathologic findings in patients with PAH, including hyperproliferative plexiform lesions [17]. Here, KDR is linked to pulmonary arterial hypertension.