C63-32 A Tale of Two Shunts: High Output Heart Failure in a Patient With Hereditary Hemorrhagic Telangiectasia

Abstract Introduction Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare autosomal dominant genetic disorder that leads to arteriovenous malformations (AVMs) in the skin, mucous membranes, and visceral organs including the lungs, liver, and brain. Case Description A 63-year-old man with HHT, heart failure with preserved ejection fraction, obesity, obstructive sleep apnea, and chronic kidney disease presented with one week of progressive dyspnea, abdominal distension, and bilateral leg swelling. Pertinent history included recurrent small-volume epistaxis, two episodes of gastrointestinal bleeding, and three admissions for acute decompensated heart failure within six months. On admission he was hemodynamically stable on room air. Notable labs included hemoglobin 7.5 g/dL, creatinine 2.62 mg/dL (baseline 1.5), B-type natriuretic peptide 1,037 pg/mL, and normal troponin. Chest computed tomography revealed enlarged pulmonary vasculature consistent with pulmonary AVMs. Transthoracic echocardiography (TTE) showed preserved left ventricular ejection fraction 60-65%, biatrial and right ventricular dilation, moderate tricuspid regurgitation, right ventricular systolic pressure 66 mmHg, and reversed hepatic venous systolic flow. TTE with bubble study revealed microbubbles after five cardiac cycles indicating an intrapulmonary shunt. Cardiac catheterization confirmed a high-output state (cardiac index 5.5-5.9 L/min/m²) with mean pulmonary artery pressure 39 mmHg, pulmonary capillary wedge pressure 19 mmHg, pulmonary vascular resistance (PVR) 2 WU, systemic vascular resistance 345 dynes-sec/cm, and hepatic venous pressure gradient (HVPG) 0 mmHg. Given the patient’s normal PVR and normal saturation on room air, the pulmonary shunt was considered to be small and unlikely to be contributing to his high cardiac output state. Meanwhile, abdominal ultrasound revealed elevated portal vein velocities with arterial waveforms consistent with an arterioportal fistula. Abdominal magnetic resonance imaging showed prominent distal vessels in the upper liver and patent hepatic and portal veins. Given the evidence, the patient’s high output heart failure was ultimately attributed to the hepatic AVMs with a lesser contribution from anemia. The patient’s condition improved with aggressive diuresis, and he was referred to an HHT center of excellence for pre-liver transplantation evaluation. Discussion HHT is a rare autosomal dominant vascular disorder characterized by telangiectasias and AVMs. This case highlights the importance of considering visceral AVMs as a potential cause of high output heart failure in patients with HHT and of performing a comprehensive evaluation in order to identify the causative lesion. This abstract is funded by: None