Blood access in daily hemodialysis

Abstract

Frequent dialyses are sometimes perceived as increasing the risk of blood access malfunction and decreased longevity. This review of the literature, however, indicates that the failure rates and overall fistula survival appear to be better with more frequent dialyses than with routine dialysis frequency, although the reasons for this phenomenon are not clear. One of the possible explanations is that frequent dialyses are associated with fewer intradialytic hypotensive episodes, which are very detrimental to the blood access. Another possible explanation is the generally lower blood flow used with more frequent hemodialyses, particularly long nocturnal hemodialysis. Finally, a decreased clotting tendency and decreased rates of hematoma formation at the puncture sites are additional possible explanations. Complication rates with bridge grafts are not higher with more frequent compared to routine thrice-weekly hemodialysis sessions. No such comparative data are available, however, for central-vein catheters. This lack of comparisons seems to stem from the intuitive assumption by nephrologists that hemodialyses that are more frequent should not adversely impact catheter complication rates and survival. No data at all are available on the use of the Dialock(R) hemodialysis system (Biolink Corp., Norwell, MA, USA) and LifeSite hemodialysis access system (Vasca, Inc., Tewksbury, MA, USA), two newer forms of hybrid access in patients undergoing frequent hemodialyses. Current evidence shows that the perceived risk of blood access malfunction and decreased longevity when patients undergo more frequent hemodialysis is not supported by the current literature.