AV Fistula-Associated Shunt as a Reversible Cause of Severe PH: A Case Report

Introduction: Pulmonary hypertension (PH) is a rare disease associated with poor outcomes if not promptly treated. For some patients, a reversible etiology can be identified, making timely diagnosis and classification essential. We present a case of recurrent massive hemoptysis in a young man with end-stage renal disease (ESRD), where identification of PH due to shunting through a peripheral arteriovenous fistula (AVF) allowed for definitive management and clinical improvement.


Description: A 29-year-old man with SLE complicated by lupus nephritis and ESRD on hemodialysis via right upper extremity AVF, as well as antiphospholipid syndrome with recurrent pulmonary emboli (PE) on warfarin, was admitted to the MICU for massive hemoptysis requiring intubation. Bronchoscopy revealed no endobronchial lesions or active hemorrhage. CT Pulmonary Angiogram showed chronic PE and evidence of PH, without clear hemorrhage source. Hemoptysis spontaneously resolved, and he was discharged with pulmonary follow up to evaluate for PH. He was readmitted 2 weeks later for recurrent massive hemoptysis. TTE showed severely enlarged RV, moderately reduced systolic function, and estimated RVSP of 115mmHg. Right heart catheterization (RHC) revealed precapillary PH with a high cardiac output (mPAP 51 mmHg, PAWP 10 mmHg, CO 8.5 L/min by thermodilution, PVR 4.8 WU) and left-to-right shunting (Qp/Qs = 1.6). Shunt was localized to the right brachiocephalic vein, the AVF site. Vascular ultrasound showed elevated AVF flow of 3L/min. Having identified high flow through his AVF as the cause of his PH, he underwent fistula revision reducing flow to 1L/min. He had no additional hemoptysis and was discharged with plan for TTE in 1 month.


Discussion: This case highlights a rare but important cause of PH: high-output cardiac physiology from an AVF. AVF-related shunting can exacerbate RV overload, especially when flow exceeds 2 L/min, increasing pulmonary circulation volume and worsening PH. In this patient with multiple PH risk factors, RHC was essential to identify the hemodynamic burden of AVF-related shunting. Surgical correction led to symptom resolution and may ultimately reduce PH severity. This case underscores the importance of evaluating AVF flow in ESRD patients with unexplained PH as early intervention may be curative.