A Vascular Puzzle: Identifying High-Output Heart Failure in a Patient with End-Stage Renal Disease and a Fresh Arteriovenous Fistula

Introduction: We present a case highlighting high-output heart failure secondary to an acquired arteriovenous fistula for dialysis. High-output cardiac failure is a less common form of heart failure characterized by the heart pumping an increased volume of blood but failing to meet the body's metabolic demands. Case presentation: A 74-year-old female with a history of hypertension, dyslipidemia, type 2 Diabetes, and end-stage renal disease (ESRD) on hemodialysis via a left arteriovenous fistula. She presented with worsening dyspnea over 2-3 months, initially relieved post-dialysis but progressing to dyspnea at rest, orthopnea, and paroxysmal nocturnal dyspnea despite dialysis compliance. Physical exam revealed hyperdynamic heart sounds, a continuous murmur at the left subclavian area, and a large left proximal forearm arterious-venous Fistula (AVF). Transthoracic echocardiography confirmed mitral regurgitation, hyperdynamic left ventricle, with a ejection fraction (EF) 50-55%, diastolic dysfunction, and cardiomegaly suggestive of CHF (Congestive heart failure). Right heart catheterization demonstrated a cardiac output and index of 8.23/5.37. Following graft occlusion, cardiac output and an index of 4.37/2.85 were noted, suggesting a high output state. Post-procedure, the patient experienced significant symptom improvement. Discussion: Patients with ESRD on HD often require AVF creation, which, despite its benefits, carries a long-term risk of hemodynamic changes leading to HF. Diagnosing this condition involves right heart catheterization and transient AV access occlusion. Treatment challenges include managing symptoms and preventing HF progression while maintaining vascular access, with options like surgical ligation, banding techniques, and inflow reduction procedures. Given the high cardiovascular mortality in dialysis patients, often due to undiagnosed fistula-related high-output heart failure, a multidisciplinary approach is crucial. Conclusion: The diagnosis of a high-output state was confirmed through thermodilution with determination of the cardiac index pre and psot AVF ligation during a right heart catheterization. Subsequent to this, the patient's symptoms improved following a procedural intervention involving the occlusion of the AVF using a blood pressure cuff. This case underscores the importance of recognizing high-output heart failure in patients with arteriovenous fistulas, highlighting the potential benefits of targeted interventions.