Pulmonary arterial hypertension: a clot in question

Pulmonary arterial hypertension (PAH) is a group of disorders characterized by a progressive increase in pulmonary vascular resistance leading to right heart failure and premature death. We present an unusual case of PAH diagnosed initially as Idiopathic PAH (IPAH) after secondary causes were excluded which was successfully managed for a number of years with vasodilators and anticoagulation. Over the months after stopping anticoagulation (because of recurring small bowel hemorrhaging) patient developed progressive findings of right heart failure, which failed to respond to escalating doses of prostacyclin. The patient died and an autopsy revealed the surprising finding of extensive organized central pulmonary artery thrombi as is seen in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We discuss the question of whether these thrombi are generally embolic or develop in situ and recommend that clinicians have a high index of suspicion for central thrombi in patients with IPAH were anticoagulation is contraindicated.