Abstract
The hemodynamic assessment of blood access was performed by the estimation of shunt flow with ultrasonic Doppler flowmeter and cardiac output with dye-dilution technique.
(A) Subcutaneous A-V fistulae on the forearm (36 cases). Blood flow velocity of the brachial artery averaged 5 times larger on the fistula-side as compared to another side. Shunt flow was regarded as excellent when the flow velocity of the brachial artery on the fistula-side exceeded 20cm/sec and was at least twice as compared to another side. Blood flow rate of the brachial artery on the flstula-side was estimated as 517±258ml/min (m±SD) for the side-to-end anastomosis and 518±199ml/min for the side-to-side anastomosis, and was considered to be an approximation to the shunt flow. The former mode of anastomosis is preferred, because the anastomosis can be easily performed with less tension on blood vessels, and the venous distension of the hands and fingers (“sore thumb syndrome”) occurs less frequently. Though A-V fistula might increase cardiac output, the ratio of the flow rate of the brachial artery to the cardiac output was as little as 2.9-12.4% (av. 7.3%), suggesting the least possibility of the high output failure.
(B) E-PTFE grafts (9 cases). Grafts were implanted as loop-shaped on thighs or forearms. The flow rate of grafts of ID 8mm exceeded 1l/min in all patients with the occurrence of heart failure in a 77-year-old diabetics. Grafts of ID 5mm was sufficient for hemodialysis, but grafts of ID 6mm may be advised, when the possibility of the gradual occurrence of stenosis after the longterm use was taken into account.
It is concluded that the hemodynamic evaluation of blood access is useful from the clinical standpoint.
