Oh My God! I Can Breathe! Pulmonary Arteriovenous Malformation in Hereditary Hemorrhagic Telangiectasia

Abstract

INTRODUCTION: Pulmonary arteriovenous malformations (PAVMs) are commonly found in patients with Hereditary Hemorrhagic Telangiectasia (HHT). They pose significant risk and complications if they are not treated during pregnancy. CASE PRESENTATION: A 29-year-old, primagravida female, with known history of HHT, presented to her obstetrician for routine follow up. She was found to be hypoxemic by finger pulse oximetry, for which she was admitted. Upon admission, her severe hypoxemia was confirmed by arterial blood gases, which didn't improve despite increasing oxygen to a 100% by a non-rebreather (NRB) mask. She complains of chronic shortness of breath with dyspnea on minimal exertion. She has significant family history of HHT. At the age of 16 she noted acrocyanosis. By the age of 27 she was diagnosed with HHT, after a CT chest with contrast showed a large, right PAVM. She underwent an MRI/MRA of her chest confirming the presence of the PAVM (fig 1). She underwent a right heart catheterization with balloon catheter occlusion of the PAVM resulting in significant improvement in her oxygenation both subjectively & objectively (On NRB, pulseox immediately increased to 100% and PaO2 from 68.9 mmHg to 318 mmHg within a minute). Patient underwent vascular plug occlusion as a definitive treatment (fig 3). Pregnancy reached term without complications. DISCUSSION: HHT is an autosomal dominant genetic disorder that results from a multisystem vascular dysplasia. It is characterized by telangiectasias and arteriovenous malformations affecting skin, mucosa, and viscera. Manifestations of HHT are generally not present at birth, but develop with increasing age. AVMs in HHT are found in many organs, including GI tract, lungs, and CNS. They vary in size from undetectable, small, to large malformations, and various presenting symptoms depending on their location. There are two genes identified for HHT, namely HHT-1 & HHT-2. PAVMs are abnormal communication between pulmonary arterial and venous vessels. They tend to increase in size, and rarely do they regress. Bleeding is common as those vessels are fragile (hemothorax, and hemoptysis). As they bypass the smaller capillaries, they can potentially lead to paradoxical emboli, strokes, & brain abscesses. They also contribute to a right-to-left shunting with resulting hypoxemia that varies depending on the size of the shunt. Blood circulation increases during pregnancy, which put pregnant ladies with PAVMs at a higher risk of developing the above complications, in addition to jeopardizing the fetal life due to hypoxemia. PAVMs can be diagnosed with CT angiography or MR angiography. Embolization, coiling, or applying vascular plugs help in closing those anomalies. Genetic testing for HHT is available. CONCLUSIONS: This case highlights the importance of identifying and treating PAVMs in pregnant females.