Right Pulmonary Artery Agenesis With Severe PAH in a Patient With May-Thurner Syndrome

Abstract

INTRODUCTION: We describe a young woman who presnted with progressive dyspnea and limited excercise tolerance secondary to pulmonary atresia. CASE PRESENTATION: A 29 year old woman hospitalized with history of progressive exertional dyspnea for 2 years. Her significant medical conditions included May-Thurner syndrome, pulmonary embolism, and multiple DVT. She was an ex smoker and denied any illicit drug use. Her admission vital signs were stable. CVS exam revealed loud P2. CTA chest revealed chronic occlusive embolus involving the right main pulmonary artery, persistent dilatation of the pulmonary trunk and left pulmonary arterial system. Echocardiogram showed moderate RV dilation, moderate to severe pulmonary hypertension PAP 75, a normal LV size, LVEF >60%, mild. Right and left cardiac catheterization: RA 8 mm Hg. RV 110/8 mm Hg, PCWP 12, PA 110/32/58 with a normal LVEF. VQ scan showed complete absence of perfusion to the entire right lung with normal ventilation. Cardiac MRI/MRA revealed normal LV size and function, severe RV hypertrophy, ostial occlusion of the main PA with severely reduced right lung perfusion. DISCUSSION: The unilateral pulmonary artery agenesis is a rare congenital anomaly that is frequently associated with other cardiovascular abnormalities. Its prevalence is 1 in 200,000 young adults. It is usually diagnosed in childhood. Most patients who have no associated cardiac anomalies have only minor or absent symptoms and survive into adulthood. It can be extremely difficult to diagnose due to the rarity of the condition and non specific symptoms. The bronchial circulation responds with enlargement and hypertrophy to decreased pulmonary flow as in pulmonary artery atresia by developing transpleural systemic collateral vessels. Distal intrapulmonary branches of the affected artery usually remain intact and can be supplied by collateral vessel from bronchial, intercostals, internal mammary, sub diaphragmatic, subclavian or even coronary arteries. We report this case because, the condition could be observed less frequently in the left pulmonary artery, she was diagnosed at a rather late age, and did not have additional cardiac abnormality. She did have severe pulmonary hypertension that was treated with endothelin receptor antagonist. CONCLUSIONS: Pulmonary atresia is an uncommon developmental anomaly suspected on routine chest radiography. The diagnosis is suggested by hypoplasia of hilum and reduced vascularity of hemithorax. Pulmonary artery atresia should be considered in the differential diagnosis of chronic pulmonary hypertension.