Access flow volume (Qa) and survival in a haemodialysis population: an analysis of 5208 Qa measurements over a 9-year period.

BACKGROUND: The aim of this study was to determine associations between characteristics of arteriovenous access (AVA) flow volume (Qa; mL/min) and 4-year freedom from cardiovascular mortality (CVM) in haemodialysis (HD) patients. METHODS: HD patients who received a primary AVA between January 2010 and December 2017 in one centre were analysed. Initial Qa was defined as the first Qa value obtained in a well-functioning AVA by a two-needle dilution technique. Actual Qa was defined as access flow at a random point in time. Changes in actual Qa were expressed per 3-month period. CVM was assessed according to the European Renal Association-European Dialysis and Transplant Association classification. The optimal cut-off point for initial Qa was identified by a receiver operating characteristics curve. A joint modelling statistical technique determined longitudinal associations between Qa characteristics and 4-year CVM. RESULTS: A total of 5208 Qa measurements (165 patients; 103 male, age 70 ± 12 years, autologous AVA n = 146, graft n = 19) were analysed. During follow-up (December 2010-January 2018, median 36 months), 79 patients (48%) died. An initial Qa <900 mL/min was associated with an increased 4-y CVM risk {hazard ratio [HR] 4.05 [95% confidence interval (CI) 1.94-8.43], P < 0.001}. After 4 years, freedom from CVM was 34% lower in patients with a Qa <900 mL/min (53 ± 7%) versus a Qa ≥900 mL/min (87 ± 4%; P < 0.001). An association between increases in actual Qa per 3-month period and mortality was found [HR 4.48/100 mL/min (95% CI 1.44-13.97), P = 0.010], indicating that patients demonstrating increasing Qa were more likely to die. In contrast, actual Qa per se was not related to survival. CONCLUSIONS: Studying novel AVA Qa characteristics may contribute to understanding excess CVM in HD patients.

Systolic finger pressures during an Allen test before hemodialysis access construction predict severe postoperative hand ischemia.

OBJECTIVE: The Allen test is a simple bedside method for determining hand perfusion. Earlier studies in patients on hemodialysis (HD) found that an Allen test before access construction did not predict hand ischemia later on. The study aimed to assess whether an Allen test combined with finger plethysmography before access surgery has a potential to predict the onset of severe HD access induced distal ischemia (HAIDI). METHODS: Before the first access construction in patients with chronic kidney disease, systolic finger pressures (Pdig, in millimeters of mercury) were obtained using plethysmography at rest and after serial compression of the radial and ulnar artery. A decrease in Pdig (∂Pdig) was calculated as the difference between Pdig-rest and Pdig-compression. The severity of postoperative HAIDI was graded as suggested by a 2016 consensus meeting. Patients with a severe type of HAIDI (grade 2b-4, intolerable pain, invasive treatment required) were compared with controls not having HAIDI. RESULTS: A total of 105 patients with chronic kidney disease (mean age 70 ± 13 years; 65% males) receiving their first access between January 2009 and December 2018 in one center fulfilled study criteria. Ten patients (10%) developed severe HAIDI at 14 ± 5 months after access construction. Before access creation, all patients with HAIDI demonstrated a radial or ulnar dominant hand perfusion pattern compared with just 57% in controls (P = .010). Compression resulted in an almost two-fold greater ∂Pdig in patients with severe HAIDI (51 ± 8 mm Hg vs 27 ± 3 mm Hg; P = .005). A 40-mm Hg ∂Pdig cut-off value demonstrated optimal tests characteristics (sensitivity of 80%, specificity of 77%, positive predictive value of 27%, negative predictive value of 97%) indicating a 10 times greater risk of developing severe HAIDI. CONCLUSIONS: Finger plethysmography quantifying ∂Pdig during an Allen test before access creation may identify patients who have a substantially increased risk of developing severe hand ischemia after HD access surgery.

Abnormal preoperative digital brachial index is associated with lower 2-year arteriovenous fistula access patency.

OBJECTIVE: The aim of the present study was to assess whether a single measurement of the digital brachial index (DBI; systolic finger pressure/systemic pressure ratio), reflecting the arm's circulation, was associated with access patency in patients with severe chronic kidney disease scheduled for arteriovenous fistula (AVF) creation. METHODS: A bilateral DBI was obtained using digital plethysmography just before construction of the patient's first AVF from January 2009 to December 2017 at one center. A DBI of 80% to 99% was considered normal, and a DBI of <80% (low) or DBI of ≥100% (high) were considered abnormal. DBI values ipsilateral to the AVF were used for analysis. The primary and secondary access patency rates were calculated using reported standards and compared using standard statistical techniques. RESULTS: Data sets of 163 patients were obtained (69 women; age, 71 ± 12 years). The median follow-up was 40 weeks (range, 0-104 weeks; follow-up index, 99% ± 1%). Patients with abnormal preoperative DBI values had lower 2-year primary patency rates (low DBI, 25% ± 11%; high DBI, 28% ± 6%; normal DBI, 49% ± 8%; P = .018). After correction for age, sex, hypertension, diabetes mellitus, cardiovascular disease, smoking status, and a history of ipsilateral central venous catheter use, an adjusted model demonstrated that abnormal DBI values conferred an increased risk of primary patency failure (low DBI [<80%]: hazard ratio [HR], 2.25; 95% confidence interval [CI], 1.13-4.48; high DBI [≥100%]: HR, 1.74; 95% CI, 1.06-2.85; P < .030 for both). Patients with a low preoperative DBI had also had diminished secondary patency (HR, 2.86; 95% CI, 1.08-7.59; P = .035). In contrast, the diameters of the outflow veins did not determine access patency. CONCLUSIONS: Patients with abnormal DBI values before AVF construction for hemodialysis had lower 2-year access patency rates compared with patients with a normal DBI. Plethysmographic finger measurements might have a role in the preoperative counseling of patients with severe chronic kidney disease requiring an AVF.

Severe hemodialysis access-induced distal ischemia may be associated with poor survival.

BACKGROUND: Some hemodialysis patients develop hemodialysis access-induced distal ischemia due to insufficient loco-regional perfusion pressure and consequent poor arterial flow. We hypothesized that patients with severe hemodialysis access-induced distal ischemia had worse survival compared with patients with mild or no hemodialysis access-induced distal ischemia. METHODS: This single-center retrospective observational cohort study included three groups of prevalent hemodialysis patients with an upper extremity vascular access between 2006 and 2018. Symptomatic patients had signs and symptoms of hemodialysis access-induced distal ischemia and low digital brachial indices (<60%) and were divided into a mild (Grade I-IIa) and a severe hemodialysis access-induced distal ischemia (IIb-IV) group. The control group consisted of hemodialysis patients without signs of hemodialysis access-induced distal ischemia with digital brachial indices ≥60%. Factors potentially related to 4-year survival were analyzed. RESULTS: Mild hemodialysis access-induced distal ischemia-patients displayed higher digital brachial indices (n = 23, 41%, ±3) compared with severe hemodialysis access-induced distal ischemia-patients (n = 28, 24%, ±4), whereas controls had the highest values (n = 48, 80%, ±2; p < .001). A total of 44 patients (44%) died during follow-up. Digital brachial index (hazards ratio 0.989 [0.979-1.000] p = .046) was related to overall mortality following correction for presence of arterial occlusive disease (hazards ratio 2.28 [1.22-4.29], diabetes (hazards ratio 2.00 [1.07-3.72], and increasing age (hazards ratio 1.03 [1.01-1.06] as was digital pressure (hazards ratio 0.990 [0.983-0.998], p = .011). Overall survival was similar in mild hemodialysis access-induced distal ischemia and controls (2-year, 79% ±5; 4-year, 57% ±6, p = .818). In contrast, 4-year survival was >20% lower in patients with severe hemodialysis access-induced distal ischemia (2-year 62%± 10; 4-year 34% ± 10; p = .026). CONCLUSION: Presence of severe hemodialysis access-induced distal ischemia may be associated with poorer survival in hemodialysis patients. Lower digital brachial index values are associated with higher overall mortality, even following correction for other known risk factors.

Abnormal digital brachial index prior to hemodialysis access construction and cardiovascular mortality.

INTRODUCTION: An abnormal ankle-brachial index indicating presence of peripheral arterial disease (PAD) is known to predict mortality in end-stage renal disease (ESRD). Hand ischemia, reflected by low finger pressures, is also a factor associated with increased mortality in patients undergoing hemodialysis (HD). The Aim of the present study is to determine whether an abnormal digital brachial index in ESRD patients prior to HD access surgery is related to lower survival rates. METHODS: A digital brachial index (DBI, systolic finger pressure/systolic brachial arterial pressure) was obtained using digital plethysmography in ESRD patients before construction of a primary HD access between January 2009 and December 2018 in a single center. Patients were grouped based on categories of DBI (low <80%, normal 80-99%, high ≥100%). Overall and cardiovascular mortality were assessed with the ERA-EDTA classification system (ERA-EDTA codes 11, 14-16, 18, and 22-26, 29). Factors potentially influencing survival rates were analyzed using standard statistics. FINDINGS: Follow-up was available in 199 patients (female n = 80; age 70 years ±12; follow-up index 99% ±1). Overall, 2 and 4 years survival were similar among DBI groups Moreover, 2 and 4 years freedom from cardiovascular death were also not different (low DBI 80% ±8 and 58% ±11; normal DBI 86% ±4 and 75% ±6; high DBI 74% ±6 and 61% ±7). Following correction for age, diabetes mellitus, cardiovascular disease and smoking, a high DBI conferred a significantly increased risk of cardiovascular mortality (HR 2.09 [1.06-4.13], P = 0.03) and a trend toward higher overall mortality (HR 1.69 [0.98-2.93], P = 0.06). DISCUSSION: ESRD patients with an abnormally elevated DBI before HD access creation have an increased risk of cardiovascular mortality in the first four postoperative years.

Revision using distal inflow for high flow hemodialysis access alters arterial flow characteristics in the dialysis arm.

OBJECTIVE: Revision using distal inflow (RUDI) is currently proposed in patients on hemodialysis having a high flow access (HFA; >2 L/min) or hemodialysis access-induced distal ischemia (HAIDI). However, a recurrence of high flow or hand ischemia is not unusual in the years after RUDI. The aim of the present study was to describe changes in flow characteristics and arterial diameters in the dialysis arm after RUDI for HFA. METHODS: Volume flow, diameter, peak systolic velocity and end diastolic velocity of the brachial artery (BA) were studied 2 and 12 months after RUDI using duplex imaging. In a portion of patients, these characteristics were also assessed at proximal and distal portions of radial and ulnar arteries (proximal forearm radial artery, distal radial artery, ulnar artery, and distal ulnar artery), and in the greater saphenous venous interponate. HFA patients were grouped according to presence of concomitant hand ischemia (HFA-HAIDI) or absence (HFA). RESULTS: Fifteen patients (54 ± 16 year old; 10 males; HFA-HAIDI, n = 6; HFA, n = 9) with a BA HFA (flow volume, 2740 ± 322 mL/min) undergoing RUDI were studied between March 2011 and October 2016 in two Dutch hospitals. After 2 months, flow volume had decreased (1180 ± 189 mL/min), but again increased at 12 months (1520 ± 217 mL/min; P < .001). BA diameters did not change (7.4 ± 0.5 mm), but proximal forearm radial diameters doubled (overall 2.6 ± 0.2 mm to 5.4 ±1.0 mm; P < .001), albeit less prominent in HFA-HAIDI (+80%) than in HFA (+130%; P = .019). During follow-up, the distal ulnar artery peak systolic velocity in HFA-HAIDI (83 ± 10 cm/s) was higher compared with the HFA group (54 ± 5 cm/s; P < .01). Dilatation was not present in the greater saphenous venous interponate. CONCLUSIONS: RUDI for HFA reduction does not reverse BA dilatation, suggesting irreversible structural arterial wall damage possibly contributing to recurrent high flow. Radial artery remodeling is attenuated in HFA patients previously reporting concurrent hand ischemia diminishing the likelihood of high flow recurrence in this subgroup.

Three Year Patency and Recurrence Rates of Revision Using Distal Inflow with a Venous Interposition Graft for High Flow Brachial Artery Based Arteriovenous Fistula.

OBJECTIVES: Upper arm arteriovenous fistulas (AVF) occasionally develop high flow. Revision using distal inflow (RUDI) effectively reduces flow of high flow accesses (HFA) in the short-term and is also popularised for treatment of haemodialysis access induced distal ischaemia (HAIDI). The long-term efficacy is unknown. The study's aim was to report on 3 year RUDI patency and recurrence rates for HFA with and without HAIDI. MATERIAL AND METHODS: This was a retrospective cohort study of patients with a HFA with or without HAIDI undergoing RUDI using greater saphenous vein (GSV) interposition between March 2011 and October 2017 at three facilities. AVFs were termed HFA if flow volumes exceeded 2 L/min on two consecutive measurements using dilution techniques. HAIDI was diagnosed as recommended. Following RUDI, follow up was not different from standard care in AVF patients. Data on post-operative flows and re-interventions were extracted from electronic patient files. Loss to follow up was avoided. Rates of patency and HFA recurrence were analysed. RESULTS: During the observation period, 21 patients were studied (7 females, 54 years ± 3). Fourteen had uncomplicated HFA whereas seven had additional HAIDI. Immediately post-operatively, flows decreased threefold (3120 mL/min ± 171 vs. 1170 mL/min ± 87, p < .001). Overall 3 year primary patency was 48% ± 12 (HFA, 55% ± 15 vs. HAIDI/HFA, 29% ± 17, p = .042). Secondary patency was identical in both groups (overall, 84% ± 9). Interventions were percutaneous transluminal angioplasty (n = 12, 9 patients), thrombectomy (n = 7, 3 patients), and revision with new interposition grafts (n = 3). After 3 years, 51% ± 12 were free of high flow (HFA, 32% ± 13 vs. HAIDI/HFA, 100%, p = .018). High immediate post-operative access flow predicted recurrence (OR 1.004 [1.000-1.007], p = .044). Patients with recurrence were 12 years younger than those without (p = .055). CONCLUSION: RUDI with GSV interposition for HFA offers acceptable patency rates after 3 years although re-interventions are often required. High immediate post-operative flows and young age are associated with recurrent high flow.

Basilic vein transposition for unsuitable upper arm hemodialysis needle access segment may attenuate concurrent hand ischemia.

INTRODUCTION: Some hemodialysis patients with a brachial arteriovenous fistula (AVF) have an unsuitable upper arm needle access segment (NAS) necessitating basilic vein transposition (BVT). It was frequently observed that a portion of these patients spontaneously experienced a warmer and less painful dialysis hand after BVT. Aim of this study was to determine whether BVT for an inadequate NAS attenuated hemodialysis access-induced distal ischemia in patients with a brachial AVF. METHODS: Patients with a brachial AVF and an unsuitable NAS also reporting hand ischemia and scheduled to undergo BVT between 2005 and 2016 in a single facility were studied. Hand ischemia was graded as proposed in a 2016 consensus meeting. Hand ischemic questionnaire (HIQ-) scores (0 points, no ischemia-500 points, maximal ischemia), digital brachial index (DBI, ischemia <0.6) and access flow (mL/min) before and after BVT were compared. The cephalic vein and all side branches of the basilic vein were ligated during the BVT. FINDINGS: Ten patients were studied (8 males, 61 [54-75] years). BVT was performed 8 [4-10] months following the initial AVF construction. HIQ-scores dropped from 220 [71-285] to 9 [0-78] (P = 0.043) postoperatively, whereas DBI increased from 0.51 [0.39-0.67] to 0.85 [0.68-0.97] (P = 0.012). DBI and HIQ-scores were inversely correlated (R2 =71%, P = 0.001). Access flows dropped significantly (Flowpre 1120 mL/min [1100-2300] vs. Flowpost 700 mL/min [600-1760]; P = 0.018). Surgery-associated complications were absent and dialysis continued uninterruptedly. Eight patients reported total recovery from hand ischemia six weeks postoperatively. DISCUSSION: Basilic vein transposition for an unsuitable upper arm needle access segment may attenuate hand ischemia in patients with a brachial AVF previously reporting hemodialysis access-induced distal ischemia.