[Choice and management of anticoagulation during CRRT].

Continuous renal replacement therapies (CRRT) are widely used in the treatment of acute kidney injury. Several causes, related to the treatment itself or to the patient's condition, determine the coagulation of the extracorporeal circuit. These interruptions (or down-time) have a negative impact on the effectiveness of the treatment in terms of solute clearance and fluid balance. Historically, the choice of anticoagulant has fallen on unfractionated heparin because it is cheap and easy to use. Today, the use of citrate is recommended in most instances because of its high efficacy and safety. Several studies demonstrate the superiority of citrate in terms of filter survival. The reduction of down-time results in a reduction of the delta between the prescribed dialysis dose and the dose that is actually administered (ml/Kg/hour of collected effluent). The literature also agrees that there is a reduction in the incidence of major bleeding events when citrate is used instead of heparin, although there is no impact on mortality rates. Some technical and clinical complexities, secondary to citrate action both as anticoagulant and buffer, still exist in the use of regional citrate anticoagulation. However, complications due to citrate use, such as acid-base balance disorders and hypocalcaemia, are rare and easily reversible. There is not much data about the costs and benefits of using citrate instead of heparin; according to the experience within our own Unit, we have observed a reduction in costs when the data is normalized for 35 ml of effluent administered. Appropriate protocols, accurate surveillance and the automated management of regional citrate anticoagulation thanks to dedicated software make this technique safe and effective.

Citrate Anticoagulation during Continuous Renal Replacement Therapy.

During extracorporeal dialysis, some anticoagulation strategy is necessary to prevent the coagulation of blood. Heparin has historically been used as an anticoagulant because of its efficacy combined with low cost. However, a variable incidence of hemorrhagic complications (5-30%) has been documented in patients undergoing continuous renal replacement therapy (CRRT) with heparin as an anticoagulant. Citrate has anticoagulation properties secondary to its ability to chelate calcium, which is necessary for the coagulation cascade. Citrate may thus be used in a regional anticoagulation (RCA), limited to the extracorporeal circuit of CRRT, to avoid systemic anticoagulation. Recent meta-analysis confirmed the advantage of RCA over heparin in terms of incidence of bleeding during CRRT. Moreover, an increase in filter lifespan is documented, with a secondary advantage in reaching the prescribed dialysis dose. In our experience, we could confirm this positive effect. In fact, with a progressive increase in the proportion of CRRT with citrate as RCA, we obtained a reduction in the number of filters used for every 72 h of treatment (from 2.4 in 2011 to 1.3 in 2015), and most importantly, a reduction in the difference between the prescribed and delivered dialysis doses (from 22 to 7%). Citrate has an intense effect on the acid-base balance as well, if fully metabolized through the Krebs cycle, due to the production of bicarbonate. Even more severely ill patients, such as those with liver dysfunction, may be treated with RCA without severe complications, because modern machines for CRRT are equipped with simple systems that are able to manage the citrate infusion and control the calcium levels, with minimal risks of metabolic derangements.

Impact of duplex ultrasound surveillance program on patency of prosthetic arteriovenous graft for hemodialysis: a single-center experience.

BACKGROUND: Arteriovenous prosthetic graft (AVG) is an alternative hemodialysis vascular access choice; however, its performance is limited by a high rate of thrombosis. The aim of the study was to compare the long-term secondary patency of AVG in patients undergoing a surveillance program and the long-term secondary patency of AVG in patients with clinical assessment of AVG malfunction. METHODS: From 2009 to 2012, all patients with AVG entered in a duplex ultrasound (DUS) surveillance program (at 3 months and then every 6 months postoperatively) to assess AVG malfunction and/or stenosis (stenosis >50% and blood flow decrease [<600 mL/min]) and eventually treated by endovascular revascularization. AVG long-term patency in the surveillance group was compared with that obtained in a historical control group in which the malfunction was clinically detected. As secondary end point, the central vein catheter (CVC) placement after AVG thrombosis was compared in the 2 groups. RESULTS: Sixty patients were included in the study, 33 (55%) in the surveillance program and 27 (45%) in the historical group. The 2 groups had similar clinical characteristics and follow-up (59, interquartile range [IQR]: 45 vs. 56 [IQR, 40 months], P = 0.32). Fifteen (45%) AVG malfunctions were detected in the surveillance group and successfully treated (10 [66.6%] angioplasty and 5 [33.4%] angioplasty stenting). No malfunction was detected in the historical control group. By Kaplan-Meier analysis, the 5-year secondary patency was significantly higher in the surveillance group compared with the historical group: 42 ± 13% vs. 9 ± 7%, P = 0.03. By Cox analysis, the DUS surveillance was a significantly protective factor for AVG thrombosis, otherwise the use of CVC before the AVG and diabetes mellitus were AVG thrombosis risk factors. The CVC placement was significantly lower in the surveillance group compared with the historical group (14.0% vs. 42.2%, P = 0.02). CONCLUSIONS: The DUS surveillance allows a greater secondary patency compared with a clinical evaluation and reduces CVC placement rate.

The prevalence of peripheral neuropathy in hemodialysis patients.

BACKGROUND/AIMS: Uremic Neuropathy (UN) highly limits the individual self-sufficiency causing near-continuous pain. An estimation of the actual UN prevalence among hemodialysis patients was the aim of the present work. METHODS: We studied 225 prevalent dialysis patients from two Italian Centers. The Michigan Neuropathy Score Instrument (MNSI), already validated in diabetic neuropathy, was used for the diagnosis of UN. It consisted of a questionnaire (MNSI_Q) and a physical-clinical evaluation (MNSI_P). Patients without any disease possibly inducing secondary neuropathy and with MNSI score ≥ 3 have been diagnosed as affected by UN. Electroneurographic (ENG) lower limbs examination was performed in these patients to compare sensory conduction velocities (SCV) and sensory nerve action potentials (SNAP) with the MNSI results. RESULTS: 37 patients (16.4%) were identified as being affected by UN, while 9 (4%) presented a score < 3 in spite of neuropathic symptoms. In the 37 UN patients a significant correlation was found between MNSI_P and SCV (r2 = 0.1959; p < 0.034) as well as SNAP (r2 = 0.3454; p = 0.027) both measured by ENG. CONCLUSIONS: UN is an underestimated disease among the dialysis population even though it represents a huge problem in terms of pain and quality of life. MNSI could represent a valid and simple clinical-instrumental screening test for the early diagnosis of UN in view of an early therapeutic approach.

Interaction between parathyroid hormone and the Charlson comorbidity index on survival of incident haemodialysis patients.

BACKGROUND: Haemodialysis patients are ageing and have with a high rate of comorbidities. The impact of this novel clinical setting on intact parathyroid hormone (iPTH) is not well established. METHODS: For this observational, prospective multicentre cohort study, incident haemodialysis patients were recruited in 40 Italian centres and followed up for a mean period of 18 +/- 6.7 months. Clinical characteristics and biochemistry were recorded at baseline. Comorbid conditions were scored by the Charlson comorbidity index (CCI). RESULTS: Data of 411 patients (mean age: 66.5 +/- 14.8 years; 17.3% >80 years old) were recorded. The mean CCI was 4.17 +/- 2.8. In patients with CCI >0, an inverse correlation was observed between CCI (excluding age) and iPTH (P = 0.00002). Independently of CCI, patients with iPTH <150 pg/ml had 76% as high as the risk of all-cause mortality. After multivariable adjustment, the combination of the first tertile of iPTH with second and third tertiles of CCI was significantly associated with all-cause mortality (RR = 3.83, P = 0.02; RR = 3.79, P = 0.01, respectively). CONCLUSIONS: Incident haemodialysis patients suffer from a high rate of clinical complications. In these patients, low iPTH and high CCI are often associated and very likely responsible for an adverse outcome.