Arteriovenous Fistula, Blood Flow, Cardiac Output, and Left Ventricle Load in Hemodialysis Patients

The aim of this study was to investigate an association between vascular access blood flow (QVA), cardiac output (CO), and load of left ventricle (LLV) using a simple physical model calculation based on real data, specifically in patients with high access blood flow arteriovenous fistula (AVF). Vascular access blood flow, CO, and peripheral vascular resistance (PR) were determined by ultrasound dilution technique (HD01; Transonic Systems, Inc., Ithaca, NY). Load of left ventricle was calculated using simplified formula: LLV = PR X CO(2). This total load was computationally divided into the part spent to run the flow QVA through the AVF (LLV(AVF)) and that part ensuring the flow (CO - QVA) through the vascular system. The model calculation was first performed in a selected group of 15 patients with high access blood flow (QVA > 1,300 ml/min, group 1) and later extended for comparison by another group of 40 unselected patients with access blood flow in lower range (QVA range 200-1,400 ml/min, group 2). Mean LLV in group 1 was 2.10 +/- 0.68 W. LLV(AVF) was 21.8% of total LLV. Mean LLV in group 2 was 1.2 +/- 0.5 W. LLV(AVF) was 11.1% of total LLV. Our computational results suggest that AVF in typical range of QVA shall not increase heart load significantly. ASAIO Journal 2010; 56:200-203.