IT'S NOT THE HEART

Abstract

TOPIC: Pulmonary Vascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: HOHF is suspected when patients present with clinical symptoms of CHF but have an elevated CI typically above 4L/min/m2 [1]. These patients can exhibit signs and symptoms of CHF and have PH as a result of elevated blood flows through the pulmonary vasculature. CASE PRESENTATION: A 56 year-old male kidney transplant recipient (KTR) presented with shortness of breath, lower extremity edema 3-months after cadaveric renal transplantation. He had a history of chronic mild systolic cardiac dysfunction (EF 50%), pulmonary hypertension (WSPH group II), and diabetes mellitus type 2 prior to kidney transplantation. Physical exam was significant for +3 pitting edema of bilateral lower extremities, crackles at lung bases and a right brachiocephalic AVF with palpable thrill. Serum creatinine was 3.5mg/dL (baseline 2.0mg/dL) and Chest X ray showed pulmonary edema. Diuresis improved the edema and shortness of breath, but worsened renal function. Renal biopsy was negative for rejection. Echocardiography (TTE) revealed an elevated right ventricular systolic pressure (RVSP) and severely dilated right atrium (RA) and ventricle (RV). Right heart catheterization demonstrated elevated right and left sided filling pressures with moderate pulmonary hypertension (PH) and an elevated cardiac output/index (CO/CI). An AVF occlusion in the cath lab resulted in a significant reduction in CO 7.75 L/min and CI 3.10 L/min/m2 by thermodilution. Findings were consistent with PH secondary to high output heart failure (HOHF), likely related to AV fistula. He underwent an AVF revision with improvement of symptoms and renal function. DISCUSSION: PH is common in patients with ESRD undergoing HD via an AVF [2] and HOHF could be an easily addressable cause of PH in ESRD. HOHF can be difficult to diagnose based on echocardiography alone. RHC typically shows an elevated CO (> 8L/min, CI>4L/min/m2), AVF/G flow > 1.5L/min, and a cardiopulmonary recirculation ratio (CPR) > 0.3 [3]. Furthermore, PH prior to transplantation appears to have an adverse impact on allograft function in kidney transplant recipients (KTR) [4]. In a retrospective analysis of KTRs in a single institution, 29/113 (26%) of patients required closure of their AVF due to symptomatic CHF. The mean AVF flow rate was significantly elevated in patients requiring AVF closure compared to those managed conservatively (2197 ml/min vs. 851 ml/min) [5]. High flow rates due to increased arterial blood shunted from left to right circulation increased the preload and stroke volume and resulted in ventricular hypertrophy leading to subsequent heart failure [6]. CONCLUSIONS: In our patient, HOHF and PH secondary to an aneurysmal AVF resulted in acute cardio-renal syndrome type 1(CRS - 1) in the transplanted kidney. The improvement in both cardiac and renal function following the revision of AVF confirmed the diagnosis of cardiorenal injury due to an aneurysmal AVF. REFERENCE #1: Reddy YN, Obokata M, Dean PG, Melenovsky V, Nath KA, Borlaug BA. Long-term cardiovascular changes following creation of arteriovenous fistula in patients with end stage renal disease. Eur Heart J. 2017 Mar 6. REFERENCE #2: Schoenberg NC, Argula RG, Klings ES, Wilson KC, Farber HW. Prevalence and Mortality of Pulmonary Hypertension in ESRD: A Systematic Review and Meta-analysis. Lung. 2020 Jun;198(3):535-45. REFERENCE #3: Wijnen E, Keuter XH, Planken NR, van der Sande FM, Tordoir JH, Leunissen KM, et al. The relation between vascular access flow and different types of vascular access with systemic hemodynamics in hemodialysis patients. Artif Organs. 2005 Dec;29(12):960-4. DISCLOSURES: Advisory Committee Member relationship with Janssen pharmaceutical Please note: 4/2020 - 4/2021 Added 04/27/2021 by Rahul Argula, source=Web Response, value=Consulting fee Advisory Committee Member relationship with United Therapeutics Please note: 2019-2021 Added 04/27/2021 by Rahul Argula, source=Web Response, value=Consulting fee Advisory Committee Member relationship with Breathe Technologies Please note: 2019 Added 04/27/2021 by Rahul Argula, source=Web Response, value=Consulting feeeducational grant relationship with Reata pharmaceuticals Please note: 2018-2019 Added 04/27/2021 by Rahul Argula, source=Web Response, value=Grant/Research Consultant relationship with Accordant health / CVS Please note: 2020 - 2021 Added 04/27/2021 by Rahul Argula, source=Web Response, value=Consulting fee no disclosure on file for mona haj; No relevant relationships by Elena Vlachos, source=Web Response