Ankle-Brachial Index: A Simple Way to Predict Mortality among Patients on Hemodialysis - A Prospective Study

Abstract

BackgroundAnkle-brachial index (ABI) can access peripheral artery disease and predict mortality in prevalent patients on hemodialysis. However, ABI has not yet been tested in incident patients, who present significant mortality. Typically, ABI is measured by Doppler, which is not always available, limiting its use in most patients. We therefore hypothesized that ABI, evaluated by a simplified method, can predict mortality in an incident hemodialysis population.Methodology/Principal FindingsWe studied 119 patients with ESRD who had started hemodialysis three times weekly. ABI was calculated by using two oscillometric blood pressure devices simultaneously. Patients were followed until death or the end of the study. ABI was categorized in two groups normal (0.9–1.3) or abnormal (<0.9 and >1.3). There were 33 deaths during a median follow-up of 12 months (from 3 to 24 months). Age (1 year) (hazard of ratio, 1.026; p = 0.014) and ABI abnormal (hazard ratio, 3.664; p = 0.001) were independently related to mortality in a multiple regression analysis.ConclusionsAn easy and inexpensive technique to measure ABI was tested and showed to be significant in predicting mortality. Both low and high ABI were associated to mortality in incident patients on hemodialysis. This technique allows nephrologists to identify high-risk patients and gives the opportunity of early intervention that could alter the natural progression of this population.

Predictive Factors of One-Year Mortality in a Cohort of Patients Undergoing Urgent-Start Hemodialysis

“…Altogether, this clinical scenario reveals a failure in the primary health care system. Nonetheless, the mortality rate was still low compared with other studies [18]. The access to a major complexity hospital and the quality of HD offered during the follow-up, may explain, at least partially, the observed mortality rate.…”

High Dialysate Calcium Concentration May Cause More Sympathetic Stimulus During Hemodialysis

“…ABI is a well-established marker of mortality among HD patients [8,13,22]. Acute changes on ABI from pre to post dialysis are not usually reported.…”

“…The measurements were done using two oscillometric devices (Omron 705 CP; Omron Corp., Tokyo, Japan) simultaneously to measure the blood pressure in the upper and lower extremities, as previously described by our group [8,12]. Cuffs were comfortably set in place, adjusted to the arm above the cubital malleolus with the cuff directed towards the brachial artery trajectory, and directed toward the trajectory of the posterior tibial artery.…”

“…Ankle brachial index (ABI), another marker of mortality in patients on HD [8] is correlated to HRV in both, normal subjects [9,10] and in patients with high cardiovascular risk [11]. The ABI, which is calculated by the division of the higher systolic BP at the ankle by the higher systolic BP at the arm, is usually assessed pre dialysis.…”

“…A lower ABI usually indicates peripheral artery disease, whereas an elevated ABI indicates arterial sclerosis due to a more pronounced calcification of the vessel wall. Both low and high ABI are associated with increased mortality in patients on HD [8,13]. Since there is an interaction between the autonomic nervous system and the vascular response [14], acute changes in ABI during HD may be a result of the sympathetic response to ultrafiltration.…”