EFFECT OF HEMODYNAMIC VARIABLES ON SURGICALLY CREATED ARTERIOVENOUS-FISTULA FLOW

Background. The immediate success and flow rate of a newly constructed arteriovenous fistula is dependent on several haemodynamic factors af fecting the inflow and outflow of the fistula. Methods. In this study we evaluated the effect of preoperative arterial blood pressure, arter ial inflow, subclavian venous Bow, and operative venous outflow resist ance on the immediate success, with special reference to the quantity of the fistula Bow in 32 patients undergoing internal arteriovenous fi stula operations. Flow measurements were done by utilizing colour flow duplex imaging and measurement of venous resistance of the fistula ve in was accomplished indirectly by a newly developed simple system. Res ults. A preoperative subclavian venous flow rate of less than 400 ml/m in was associated with higher rate of immediate failures (P < 0.05) wi th a negative predictive value of 100% with 100% sensitivity. Regardin g immediate failures, no other haemodynamic measurement was found to a ffect the success of a newly constructed fistula significantly. A line ar correlation between the measured haemodynamic values and the quanti ty of postoperative fistula flow was not found. However, an arterial i nflow value of greater than or equal to 40 ml/min was associated with higher fistula Bow rates (P<0.05). Conclusions. The immediate success and flow of a newly constructed arteriovenous fistula is mainly depend ent on arterial inflow and subclavian venous flow. An arterial inflow rate of 40 ml/min or more and subclavian venous flow rate of 400 ml,mi n or more measured by colour Bow duplex imaging prior to the operation will be associated with better outcomes, and therefore the use of col our Bow duplex imaging is warranted during the evaluation of patients who are candidates for an arteriovenous fistula operation.