Anticoagulation during haemodialysis in patients at high-risk of bleeding

Comparison of PPT and APTT in Pre and Post-Hemodialysis Patients as the Heparin-Exposed Effect

Evaluations on Plasma Prothrombin Time (PPT) and Activated Partial Thromboplastin Time (APTT) are required in patients with Chronic Kidney Disease (CKD) stage V to determine the risk of bleeding after hemodialysis (HD) using heparin as the anticoagulant. This study aimed to compare the results of PPT and APTT in pre and post-hemodialysis patients with minimum dose of heparin. This was an observational-analytical study with cross-sectional design. The samples were collected in HD wards of Dr. Soetomo Hospital, Surabaya. There were 50 PPT and APTT samples collected from June to August 2017. The samples were evaluated using the tool CoaDATA 501. The examination of coagulation study was conducted in Clinical Pathology Laboratory of Dr. Soetomo Hospital, Surabaya. Paired t-test and Wilcoxon signed-rank test were performed in this study. In the 50 samples, pre-hemodialysis PPT ranged between 10.2-17.6 with the mean of 12.6±2.03 seconds, while for post-hemodialysis, the range was 10.1-20.9 with the mean of 13.41±2.43 seconds. Pre-hemodialysis APPT ranged between 19.5-75.2 with the mean of 30.32±10.43 seconds, while in post hemodialysis the range was 22.21-175 with the mean of 37.52±26.40 seconds. The results of PTT evaluation in pre and post-HD showed no significant difference (p=0.083), while those of APTT showed a significant difference (p=0.035 or p<0.05). Prolongation of APTT in post-HD is due to the use of heparin as an anticoagulant that increases PPT and APTT by inhibiting antithrombin III. HD procedures cause decreased activity of coagulation factors II, IX, X, XII leading to APTT prolongation in post-HD. A significant APTT prolongation was found in post-HD patients with CKD V.

An evaluation of four modes of low-dose anticoagulation during intermittent haemodialysis

Introduction

Intensive care participants that need dialysis frequently suffer from increased risk of bleeding. Standard intermittent haemodialysis (SHD) includes anticoagulation to avoid clotting of the dialysis system. The aim of this study was to clarify which of four different low-dose anticoagulant modes was preferable in reducing the exposure to i.v. unfractionated heparin (heparin) and maintaining patency of the dialysis circuit.

Methods

Twenty-three patients on SHD were included to perform haemodialysis with four modes of low-dose anticoagulation. For comparative analyses, patients served as their own control. Haemodialysis with a single bolus of tinzaparin at the start was compared to haemodialysis initiated without i.v. heparin but priming with (1) heparin in saline (H), (2) heparin and albumin in saline (HA), (3) heparin and albumin in combination with a citrate-containing dialysate (HAC), (4) saline and usinga heparin-coated filters (Evodial®). The priming fluid was discarded before dialysis started. Blood samples were collected at 0, 30 and 180 min during haemodialysis. Smaller bolus doses of heparin (500 Units/dose) were allowed during the modes to avoid interruption by clotting.

Findings

The mean activated partial thromboplastin (APTT) time as well as the doses of anticoagulation administered was highest with SHD and least with HAC and Evodial®. Mode H versus SHD had the highest rate of prematurely interrupted dialyses (33%, p = 0.008). The urea reduction rate was less with Evodial® vs. SHD (p < 0.01). One hypersensitivity reaction occurred with Evodial®. Changes in blood cell concentrations and triglycerides differed between the modes.

Discussion

If intermittent haemodialysis is necessary in patients at risk of bleeding, anticoagulation using HAC and Evodial® appeared most preferable with least administration of heparin, lowest APTT increase and lowest risk for prematurely clotted dialyzers in contrast to the least plausible H mode.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2389-x) contains supplementary material, which is available to authorized users.

Comparison of the AN69ST Membrane versus Citrate-Enriched Dialysate on Clotting Events during Hemodialysis without Systemic Anticoagulation

BACKGROUND

The optimal management of anticoagulation in hemodialyzed patients with a high risk of bleeding is controversial.

METHODS

We compared premature termination of dialysis caused by clotting events between AN69ST membranes (G1) and 0.8 mmol/L citrate-enriched dialysate (G2). The number of sessions that had increased venous pressure (VP) and variations in urea-reduction ratio (URR) were analyzed.

RESULTS

Six hundred and two sessions were analyzed in 259 patients: 22.4% had sessions that ended prematurely (25% in G1 and 19.1% in G2, p = ns, OR 0.60 [0.34-1.08], p = 0.08). The increase in VP was lower in G2 (23 vs. 70, p < 0.001). URR was higher in G2 (0.56 vs. 0.60, p < 0.001).

CONCLUSION

Clotting events that led to the termination of dialysis were comparable in the 2 groups. However, UUR was better in G2, and the number of patients with increased VP in the sessions was lower in G2.

SHORT SUMMARY

Our study compared the effects of the AN69ST membrane and citrate-enriched dialysate on clotting events during the dialysis of 259 patients with a high risk of bleeding. URR was significantly better and fewer cases of increased VP occurred in the citrate group compared to the AN69 ST group. No significant difference was observed regarding the need to prematurely terminate a dialysis session.

Heparin albumin priming in a clinical setting for hemodialysis patients at risk for bleeding

INTRODUCTION

Intermittent hemodialysis (IHD) is sometimes necessary in patients with a bleeding risk, i.e., before/after surgery or brain hemorrhage. In such case IHD has to be modified to limit the conventional anticoagulation used to avoid clotting of the extracorporeal circuit (ECC). We evaluated if priming using a heparin and albumin (HA) mixture could minimize the exposure to heparin.

METHODS

Retrospective data from 1995 to 2013 were collected from 1408 acute dialysis treatment protocols that included 321 patients. Comparisons were made between IHD patients that had increased risk for bleeding and were treated by standard anticoagulation (Group-S), and patients at increased risk of bleeding (Group-HA). The ECC in Group-HA was primed with a solution of unfractioned heparin (UFH) (5000 Units/L) and albumin (1 g/L) in saline that was discarded after priming. There were 16 different dialyzers in the material.

FINDINGS

Comparing Group-S (n = 883) with Group-HA (n = 221), the mean age was 61.6 vs. 62.2 years (P = 0.8), dialysis time was 197 vs. 190 minutes (P = 0.002), and total dose of intravenous anticoagulant/IHD was at median 5000 Units vs. 1200 Units (P = 0.001). Twenty-four percent of patients were treated without any additional heparin. Clotting resulting in interrupted dialysis was similar in both groups (0.8% for Group-S vs. 1.0% for Group-HA, P = 0.8). No secondary bleeding was reported in either group.

DISCUSSION

HA priming minimized the risk of clotting and enabled acute IHD in vulnerable patients without increased bleeding, thus allowing completion of IHD to the same extent as for standard HD.

Vitamin E-Coated and Heparin-Coated Dialyzer Membranes for Heparin-Free Hemodialysis: A Multicenter, Randomized, Crossover Trial

BACKGROUND

Hemodialysis requires effective anticoagulation to avoid blood circuit clotting. In patients at high risk for bleeding, several alternative methods have been developed.

STUDY DESIGN

Multicenter, prospective, randomized, crossover study evaluating the noninferiority of vitamin E-coated compared with heparin-coated dialyzers in a 4-hour heparin-free hemodialysis strategy.

SETTINGS & PARTICIPANTS

32 adult long-term hemodialysis patients from 2 French hemodialysis units with well-functioning fistulas or double-lumen catheters.

INTERVENTION

Patients were randomly allocated to a first period using either vitamin E- or heparin-coated dialyzers. After a washout period of 2 hemodialysis sessions, each patient was switched to the alternative dialyzer for a second period. Each study period started with 2 hemodialysis sessions with reduced heparin dose (50% and 25% of usual heparin dose, respectively, for sessions 1 and 2) followed by 2 heparin-free sessions.

OUTCOMES

The primary end point was the percentage of successful study periods, defined as no circuit-clotting event leading to premature interruption of any of the 4 dialysis sessions. Secondary end points included total number and cumulative duration of hemodialysis sessions without clotting, number of saline solution flushes, dialysis circuit bubble trap status and dialyzer membrane status by visual inspection, and dialysis adequacy.

RESULTS

The percentage of success with vitamin E-coated dialyzers (25/32 study periods [78%]) was not inferior to that with heparin-coated dialyzers (26/32 study periods [81%]). Visual inspection showed equal numbers of clean dialysis circuit bubble traps (vitamin E-coated, 34/121; heparin-coated, 32/120), whereas clean fiber bundles were more frequently noted with the vitamin E-coated compared with heparin-coated dialyzers (25/121 vs 2/120; P=0.002).

LIMITATIONS

Results may not extrapolate to critically ill patients. Differences in dialyzer transparency may account for visual inspection scores.

CONCLUSIONS

The success rate of 4-hour heparin-free hemodialysis sessions is lower than that previously claimed in uncontrolled studies. Vitamin E-coated and heparin-coated dialyzers exposed patients to similar and unacceptable high failure rates. Further studies are required to improve heparin-free hemodialysis.

Multiple preoperative and intraoperative factors predict early fistula thrombosis in the Hemodialysis Fistula Maturation Study

OBJECTIVE

Early thrombosis (ET) contributes to autogenous arteriovenous fistula (AVF) failure. We studied patients undergoing AVF placement in the Hemodialysis Fistula Maturation Study, a prospective, observational cohort study, using a nested case-control analysis to identify preoperative and intraoperative predictors of ET.

METHODS

ET cases were compared with controls, who were matched for gender, age, diabetes, dialysis status, and surgeon fistula volume. ET was defined as thrombosis diagnosed by physical examination or ultrasound within 18 days of AVF creation. Conditional logistic regression models were fit to identify risk factors for ET.

RESULTS

Thirty-two ET cases (5.3%) occurred among 602 study participants; 198 controls were matched. ET was associated with female gender (odds ratio [OR], 2.75; 95% confidence interval [CI], 1.19-6.38; P = .018), fistula location (forearm vs upper arm; OR, 2.76; 95% CI, 1.05-7.23; P = .039), feeding artery (radial vs brachial; OR, 2.64; 95% CI, 1.03-6.77; P = .043) and arterial diameter (OR, 1.52; 95% CI, 1.02-2.26; P = .039, per mm smaller). The draining vein diameter was nonlinearly associated with ET, with highest risk in 2- to 3-mm veins. Surprisingly, ET risk was lower in diabetics (OR, 0.19; 95% CI, 0.07-0.47; P = .0004), lower with less nitroglycerin-mediated brachial artery dilation (OR, 0.42; 95% CI, 0.20-1.92; P = .029 for each 10% lower) and higher with lower carotid-femoral pulse wave velocity (OR, 1.49; 95% CI, 1.02-2.20; P = .041, for each m/s lower). Intraoperative protamine use was associated with a higher ET risk (OR, 3.26; 95% CI, 1.28-∞; P = .038). Surgeon's intraoperative perceptions were associated with ET: surgeons' greater concern about maturation success (likely, marginal, unlikely) was associated with higher thrombosis risk (OR, 8.09; 95% CI, 4.03-∞; P < .0001, per category change), as were absence vs presence of intraoperative thrill (OR, 21.0; 95% CI, 5.07-∞; P = .0001) and surgeons' reported frustration during surgery (OR, 6.85; 95% CI, 2.70-∞; P = .0004). Decreased extent of intraoperative thrill (proximal, mid or distal third of the forearm or upper arm, based on AVF placement) was also associated with ET (OR, 2.91; 95% CI, 1.31-∞; P = .007, per diminished level). Oral antithrombotic medication use was not significantly associated with ET.

CONCLUSIONS

ET was found to be associated with female gender, forearm AVF, smaller arterial size, draining vein diameter of 2 to 3 mm, and protamine use. Paradoxically, diabetes and stiff, noncompliant feeding arteries were associated with a lower frequency of ET. Absent or attenuated intraoperative thrill, and both surgeon frustration and concern about successful maturation during surgery, were correlated strongly with ET.

Results of the HepZero study comparing heparin-grafted membrane and standard care show that heparin-grafted dialyzer is safe and easy to use for heparin-free dialysis

Heparin is used to prevent clotting during hemodialysis, but heparin-free hemodialysis is sometimes needed to decrease the risk of bleeding. The HepZero study is a randomized, multicenter international controlled open-label trial comparing no-heparin hemodialysis strategies designed to assess non-inferiority of a heparin grafted dialyzer (NCT01318486). A total of 251 maintenance hemodialysis patients at increased risk of hemorrhage were randomly allocated for up to three heparin-free hemodialysis sessions using a heparin-grafted dialyzer or the center standard-of-care consisting of regular saline flushes or pre-dilution. The first heparin-free hemodialysis session was considered successful when there was neither complete occlusion of air traps or dialyzer, nor additional saline flushes, changes of dialyzer or bloodlines, or premature termination. The current standard-of-care resulted in high failure rates (50%). The success rate in the heparin-grafted membrane arm was significantly higher than in the control group (68.5% versus 50.4%), which was consistent for both standard-of-care modalities. The absolute difference between the heparin-grafted membrane and the controls was 18.2%, with a lower bound of the 90% confidence interval equal to plus 7.9%. The hypothesis of the non-inferiority at the minus 15% level was accepted, although superiority at the plus 15% level was not reached. Thus, use of a heparin-grafted membrane is a safe, helpful, and easy-to-use method for heparin-free hemodialysis in patients at increased risk of hemorrhage.

Rationale and design of the HepZero study: a prospective, multicenter, international, open, randomized, controlled clinical study with parallel groups comparing heparin-free dialysis with heparin-coated dialysis membrane (Evodial) versus standard care: study protocol for a randomized controlled trial

Background

Anticoagulation for chronic dialysis patients with contraindications to heparin administration is challenging. Current guidelines state that in patients with increased bleeding risks, strategies that can induce systemic anticoagulation should be avoided. Heparin-free dialysis using intermittent saline flushes is widely adopted as the method of choice for patients at risk of bleeding, although on-line blood predilution may also be used. A new dialyzer, Evodial (Gambro, Lund, Sweden), is grafted with unfractionated heparin during the manufacturing process and may allow safe and efficient heparin-free hemodialysis sessions. In the present trial, Evodial was compared to standard care with either saline flushes or blood predilution.

Methods

The HepZero study is the first international (seven countries), multicenter (10 centers), randomized, controlled, open-label, non-inferiority (and if applicable subsequently, superiority) trial with two parallel groups, comprising 252 end-stage renal disease patients treated by maintenance hemodialysis for at least 3 months and requiring heparin-free dialysis treatments. Patients will be treated during a maximum of three heparin-free dialysis treatments with either saline flushes or blood predilution (control group), or Evodial. The first heparin-free dialysis treatment will be considered successful when there is: no complete occlusion of air traps or dialyzer rendering dialysis impossible; no additional saline flushes to prevent clotting; no change of dialyzer or blood lines because of clotting; and no premature termination (early rinse-back) because of clotting.

The primary objectives of the study are to determine the effectiveness of the Evodial dialyzer, compared with standard care in terms of successful treatments during the first heparin-free dialysis. If the non-inferiority of Evodial is demonstrated then the superiority of Evodial over standard care will be tested. The HepZero study results may have major clinical implications for patient care.

Trial registration

ClinicalTrials.gov NCT01318486

Effects of argatroban as an anticoagulant for intermittent veno-venous hemofiltration (IVVH) in patients at high risk of bleeding

BACKGROUND

The critically ill patients with acute renal failure (ARF) undergoing intermittent veno-venous hemofiltration (IVVH) are often at high risk of bleeding. No conventional anticoagulants can adequately achieve this task. Argatroban, a synthetic direct thrombin inhibitor, has been approved for the treatment of hemodialysis patients with antithrombin III deficiency and particularly for heparin-induced thrombocytopenia II patients. Therefore, the anticoagulating effect of argatroban in patients with a high risk of bleeding was investigated.

METHODS

One hundred and one ARF patients at high risk of bleeding were treated with predilution IVVH, assigned to a nonheparin group (n = 44) and an argatroban group (n = 57). Venous blood was collected to monitor the change of coagulant parameters pre- and post-IVVH in both groups. Activated partial thromboplastin time (APTT) value was monitored in the argatroban group at different sites and time points to adjust the dosage during IVVH.

RESULTS

All the patients in the argatroban group completed treatment successfully, whereas in the nonheparin group, clotting of the extracorporeal circuit occurred in 16.9% of patients. Furthermore, D-dimer increased slightly and platelet counts decreased post-hemofiltration in the nonheparin group. No change was found in platelet counts and coagulant parameters in the argatroban group pre- and post-hemofiltration. Argatroban prolonged the APTT by 50% at the venous site after the initial bolus and the maintenance infusion at 2 and 4 h during the treatment with no change at the arterial site. No major bleeding episodes and serious side effects were found.

CONCLUSIONS

In critically ill patients with a high risk of bleeding, argatroban is an effective and safe anticoagulant for IVVH.

An Official ATS/ERS/ESICM/SCCM/SRLF Statement: Prevention and Management of Acute Renal Failure in the ICU Patient: an international consensus conference in intensive care medicine

OBJECTIVES

To address the issues of Prevention and Management of Acute Renal Failure in the ICU Patient, using the format of an International Consensus Conference.

METHODS AND QUESTIONS

Five main questions formulated by scientific advisors were addressed by experts during a 2-day symposium and a Jury summarized the available evidence: (1) Identification and definition of acute kidney insufficiency (AKI), this terminology being selected by the Jury; (2) Prevention of AKI during routine ICU Care; (3) Prevention in specific diseases, including liver failure, lung Injury, cardiac surgery, tumor lysis syndrome, rhabdomyolysis and elevated intraabdominal pressure; (4) Management of AKI, including nutrition, anticoagulation, and dialysate composition; (5) Impact of renal replacement therapy on mortality and recovery.

RESULTS AND CONCLUSIONS

The Jury recommended the use of newly described definitions. AKI significantly contributes to the morbidity and mortality of critically ill patients, and adequate volume repletion is of major importance for its prevention, though correction of fluid deficit will not always prevent renal failure. Fluid resuscitation with crystalloids is effective and safe, and hyperoncotic solutions are not recommended because of their renal risk. Renal replacement therapy is a life-sustaining intervention that can provide a bridge to renal recovery; no method has proven to be superior, but careful management is essential for improving outcome.

Platelet dysfunction and end-stage renal disease

Patients with end-stage renal disease (ESRD) develop hemostatic disorders mainly in the form of bleeding diatheses. Hemorrhage can occur at cutaneous, mucosal, or serosal sites. Retroperitoneal or intracranial hemorrhages also occur. Platelet dysfunction is the main factor responsible for hemorrhagic tendencies in advanced kidney disease. Anemia, dialysis, the accumulation of medications due to poor clearance, and anticoagulation used during dialysis have some role in causing impaired hemostasis in ESRD patients. Platelet dysfunction occurs both as a result of intrinsic platelet abnormalities and impaired platelet-vessel wall interaction. The normal platelet response to vessel wall injury with platelet activation, recruitment, adhesion, and aggregation is defective in advanced renal failure. Dialysis may partially correct these defects, but cannot totally eliminate them. The hemodialysis process itself may in fact contribute to bleeding. Hemodialysis is also associated with thrombosis as a result of chronic platelet activation due to contact with artificial surfaces during dialysis. Desmopressin acetate and conjugated estrogen are treatment modalities that can be used for uremic bleeding. Achieving a hematocrit of 30% improves bleeding time in ESRD patients.

Water-soluble poly(ethylenimine)-based nitric oxide donors: preparation, characterization, and potential application in hemodialysis

A novel approach to potentially resolve serious thrombosis issues associated with kidney dialysis (hemodialysis) therapies is described. New water-soluble polymeric nitric oxide (NO) donors, based on the diazeniumdiolated branched poly(ethylenimine)s and their derivatives, are prepared and characterized. These macromolecular NO donors (with up to 4.15 micromol/mg of total NO release) are utilized as additives to the dialysate solution of model dialysis filters. The presence of these species can create a localized increase in NO levels at the high surface area dialysis fiber/blood interface within the hemodialyzers. Nitric oxide is a naturally occurring and potent anti-platelet agent and is expected to greatly decrease the risk of thrombosis in the dialysis units.