Can Arteriovenous Fistula Creation Cause a Dramatic Spontaneous Doubling of Estimated Glomerular Filtration Rate from 11 to 22 mL/min/1.73 m2 Body Surface Area (BSA) in a Span of Five Months? A Case Report

Introduction: Previous studies suggest deceleration of eGFR decline after vascular access creation independent of maturation. Postulated mechanisms remain speculative. Our recent experience with doubling of eGFR 5 months after AVF creation calls for further enquiry. Case Description: A 56-yo male with previously uncontrolled diabetes mellitus, hypertension and sleep apnea experienced accelerated CKD progression in late 2023-2024. He was on Amlodipine 10 mg/d, Losartan-Hydrochlorothiazide 100-25 mg/d, Spironolactone 25 mg/d, insulin and levothyroxine. Work up of acute kidney injury in November 2023 was negative. Losartan was discontinued in March 2024. Renal ultrasound was non-diagnostic in April 2024. Kidney biopsy in May 2024 revealed diabetic nephropathy. In May 2024, transient hypercalcemia one month after starting TUMS for phosphorus binder quickly resolved after TUMS was replaced with Sevelamer. Nevertheless, CKD progression persisted, Echocardiogram was normal in November 2024. A percutaneous left arm perforator vein to radial artery AVF was created in late November 2024 with a Medtronic Ellipsys Device. This was followed by an elective balloon angioplasty and 4 mm coil embolization of a venous side branch of the AVF after 3 weeks. He had an elective left basilic vein ligation in mid-March 2025, after Doppler review of the maturing AVF. As at last Nephrology Clinic visit in mid-April 2025, serum creatinine had decreased to 3.22 mg/dL (eGFR=22) (Figure). Discussion: During the Clinic visit in late April 2025, the patient felt goo - "I was also surprised by the improved kidney function". We describe spontaneous dramatic doubling of eGFR from 11 to 22 ml/min/1.73 sq. m BSA in 5 months after AVF creation. What are the implications of this observation? Our observations call for further enquiry.