Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Among patients with severe chronic kidney disease requiring an arteriovenous fistula for hemodialysis, abnormal digital-brachial index was found to be predictive of fistula patency.

Evidence Level Rating: 2 (Good)

Some patients with advanced chronic kidney disease (CKD) may require renal replacement therapies like hemodialysis (HD), at which point creation and maintenance of an arteriovenous fistula (AVF) is of great importance. AVF patency is often challenging, and repeated attempts to maintain it are burdensome to both the patient and the health care system. The purpose of this retrospective study was to determine whether the digital-brachial index (DBI) – the systolic pressure of a finger divided by the systolic pressure of the brachial artery – was associated with AVF patency at two years. 163 patients (mean [SD] age = 71 [12] years, 42% female) with CKD stage 4 or 5 were included, with 80 patients receiving a wrist-based AVF and 83 receiving an elbow-based AVF. The mean preoperative DBI was 98±18%; 67 patients had a normal DBI of 80-99%, 22 a low DBI of < 80%, and 74 a high DBI of ≥ 100%. One- and two-year primary patency rates were found to be 43±4% and 35±4%, respectively. Furthermore, the groups with abnormal DBIs were found to have the lowest rate of primary patency (low DBI 25±11%, high DBI 28±6%, normal DBI 49±8%, p = 0.018). After controlling for variables like age, sex, hypertension, diabetes mellitus, and smoking status, abnormal DBI values were the only independent predictors of primary patency (low DBI: HR 2.25, 95% CI 1.13 to 4.48, p = 0.022; high DBI: HR 1.74, 95% CI 1.06 to 2.85, p = 0.029). In all, this study suggests that abnormal DBI is an independent predictor of AVF patency among patients with severe CKD. DBI measurement, therefore, might have a role in pre- and post-procedural counseling and in predicting AVF prognosis among select patients.

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