Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients

Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients.BackgroundCurrent DOQI guidelines encourage placing arteriovenous (AV) fistulas in more hemodialysis patients. However, many new fistulas fail to mature sufficiently to be useable for hemodialysis. Preoperative vascular mapping to identify suitable vessels may improve vascular access outcomes. The present study prospectively evaluated the effect of routine preoperative vascular mapping on the type of vascular accesses placed and their outcomes.MethodsDuring a 17-month period, preoperative sonographic evaluation of the upper extremity arteries and veins was obtained routinely. The surgeons used the information obtained to plan the vascular access procedure. The types of access placed, their initial adequacy for dialysis, and their long-term outcomes were compared to institutional historical controls placed on the basis of physical examination alone.ResultsThe proportion of fistulas placed increased from 34% during the historical control period to 64% with preoperative vascular mapping (P < 0.001). When all fistulas were assessed, the initial adequacy rate for dialysis increased mildly from 46 to 54% (P = 0.34). For the subset of forearm fistulas, the initial adequacy increased substantially from 34 to 54% (P = 0.06); the greatest improvement occurred among women (from 7 to 36%, P = 0.06) and diabetic patients (from 21 to 50%, P = 0.055). In contrast, the initial adequacy rate of upper arm fistulas was not improved by preoperative vascular mapping (59 vs. 56%, P = 0.75). Primary access failure was higher for fistulas than grafts (46.4 vs. 20.6%, P = 0.001), but the subsequent long-term failure rate was higher for grafts than fistulas (P < 0.05). Moreover, grafts required a threefold higher intervention rate (1.67 vs. 0.57 per year, P < 0.001) to maintain their patency. The overall effect of this strategy was to double the proportion of patients dialyzing with a fistula in our population from 16 to 34% (P < 0.001).ConclusionsRoutine preoperative vascular mapping results in a marked increase in placement of AV fistulas, as well as an improvement in the adequacy of forearm fistulas for dialysis. This approach resulted in a substantial increase in the proportion of patients dialyzing with a fistula in our patient population. Fistulas have a higher primary failure rate than grafts, but have a lower subsequent failure rate and require fewer procedures to maintain their long-term patency

King William II of Sicily, Muslim King? Ibn Jubayr and his Conflicted Attitudes toward Christians

I examine the travel account of Spanish Muslim traveler Ibn Jubayr, who from 1183-85 undertook the Hajj, traveling to Mecca and Medina but also traversing much of the Islamic world and returning through Christian-held territories in the Holy Land and Sicily. I examine his reactions to the Christian other , and in particular his mixed response to Sicily, whose king in many ways governed and lived like an ideal Muslim ruler

Utility of xenografts: Lack of correlation between PRA and natural antibodies to swine

Among the patients that might potentially benefit from the availability of xenografts are those in kidney failure who demonstrate high levels of antibody reactivity to panels of typing lymphocytes. Such individuals with high PRA (panel reactive antibody) are unlikely to receive a renal allograft because they are highly sensitized to the vast majority of potential donors. In addition, all humans have demonstrable levels of natural antibodies reactive to distantly related species such as the pig. If there were a correlation between PRA and levels of natural antibodies, then such patients would also be at greater risk for hyperacute rejection of xenografts. We have therefore examined, in a blinded fashion, the porcine lymphocyte reactivity of sera from PRA positive donors. Subsets of the 105 sera tested were grouped by PRA level and analyzed for levels of natural antibodies detectable by a complement-dependent cytotoxicity assay on porcine lymphocytes. There was no significant difference in the range of titers of natural antibodies between subsets. Thus, there was no demonstrable correlation between levels of PRA and levels of natural antibodies to porcine lymphocytes. In addition, we studied the sera of 11 highly sensitized patients who received renal allografts and conventional triple drug immunosuppression in order to determine whether immunosuppression to maintain a vascularized allograft had an effect on PRA and/or xenoreactivity. Mean post-operative PRA was significantly lower than mean pre-operative PRA, while there was no significant difference in xenoreactivity. Thus, pretransplant immunosuppression may permit an increased opportunity to identify compatible human donors for highly sensitized recipients and will not help or hinder the pre-transplant conditioning of a candidate for xenotransplantation