Clinical Significance of Recirculation Measured by Two Needle Slow Method

Park, Dong Kyun; Kim, Tae Seog; Oh, Soo Yong; Kim, Duk Jo; Choi, Yun Young; Lee, Jong Ho; Kim, Sang Il

Abstract

OBJECTIVES
Recirculation is one of the factors preventing effective hemodialysis(HD) and one of the methods which can detect vascular access stenosis. We analyzed the possible clinical risk factors and relationship between the recirculation rate(R) and adequacy of hemodialysis. Also, we attempted to find out whether vascular access stenosis actually exist in the high R group.
METHODS
We examined the period of hemodialysis, the presence of diabetes mellitus(DM), use of artificial grafts, the venous pressure(VP) during HD, the difference(deltaKt/V) between prescribed Kt/V(Kt/V') and delivered Kt/V(Kt/V") in 113 patients(22 DM, 39 artifical graft patients) receving maintenence HD. R was obtained by two needle slow flow method. Fistulogram was performed in the high R group(R>10%) and if significant stenosis was found, surgical correction was performed followed by repeated R, VP, Kt/V" measurement.
RESULTS
As a whole R was 5.6%(+/-8.8), VP was 92mmHg(+/-44), the duration of hemodialysis was 36 months(+/-25) and Kt/V" was 1.20 (+/-0.29). The VP of the group with artificial graft was higher than that of the group with native fistula, but there was no relationship between R and duration of HD, Kt/V", deltaKt/V as a whole. The VP and deltaKt/V of group with high R(>10%) were significantly higher than the group with low R(<10%). Positive correlation between R and deltaKt/V was demonstrated in the group with high R. In six patients with high R, fistulograms were taken and significant vascular stenosis were found. After surgical correction, R was significantly decreased from 25.5% to 5.2%. On the other hand, the R as well as the rate of diabetes or prosthetic grafts were higher in the group with high VP(>or=100mmHg) than in the group with low VP(<100mmHg) as well as in patients with diabetes or prosthetic grafts,
CONCLUSION
We believe recirculation should be measured during maintenance HD especially when the patient has diabetes, artificial graft or high venous pressure during HD. When the recirculation rate is high, reconstructive vascular surgery with proprer mediacl management may lead to better dialysis adequacy.