Skin bleeding time for the evaluation of uremic platelet dysfunction and effect of dialysis

Evaluation of factors associated with bleeding following haemodialysis catheter-related procedures and the risk with anti-platelet agents

BACKGROUND

Bleeding is a potential complication following haemodialysis catheter-related procedures. Besides uraemia, bleeding risk is perceived to be even higher in patients receiving antiplatelets. This study aims to evaluate the risk factors for bleeding following dialysis catheter-related procedures.

METHODS

This is a secondary analysis of a single-centre, prospective cohort study between March 2019 and June 2020. Potential risk factors for bleeding were collected, including use of antiplatelets and anticoagulants, serum urea and haematological results. Patients were observed closely for external bleeding following haemodialysis catheter-related procedures.

RESULTS

From 413 patients screened, 250 were recruited. Of these, 177 underwent dialysis catheter insertion (157 tunnelled and 20 non-tunnelled) while 73 had dialysis catheter removed (35 tunnelled and 38 non-tunnelled). One hundred and four patients (41.6%) were on a single anti-platelet agent, of whom 75 (30.0%) were on aspirin and 29 (11.6%) had clopidogrel alone. Twenty-nine patients (11.6%) were on both aspirin and clopidogrel.There were 36 episodes (14.4%) of bleeding. The risk of bleeding was not significantly higher with the use of aspirin alone (odds ratio = 0.85, 95% CI: 0.36-2.02, p = 0.709), clopidogrel alone (odds ratio = 1.04, 95% CI: 0.31-3.49, p = 0.953) and both aspirin and clopidogrel (odds ratio = 0.95, 95% CI: 0.28-3.25, p = 0.938). In a multivariate analysis, none of the known bleeding risk factors had a statistically significant association with bleeding.

CONCLUSIONS

Overall, the use of antiplatelet agents was not associated with an increased risk of bleeding.

Spontaneous bleeding in chronic kidney disease: global coagulation assays may predict bleeding risk

Background

Chronic kidney disease (CKD) is associated with increased bleeding and thrombotic risks. Standard blood tests do not sufficiently quantify these risks. Global coagulation assays (GCAs) provide a more comprehensive assessment of coagulation.

Objectives

We aimed to evaluate if GCAs are predictive of spontaneous major bleeding (sMB) in CKD.

Methods

Adult patients with CKD (estimated glomerular filtration rate, <30 mL/min/1.73m2) were recruited to this pilot prospective observational study. Testing with GCAs (thromboelastography, overall hemostatic potential, calibrated automated thrombogram, and plasminogen activator inhibitor-1) was performed, and the results were correlated to sMB events.

Results

Eighty-seven CKD patients (median age, 67 years; 67.8% male) were included, with median follow-up of 3.1 years. CKD patients demonstrated elevated fibrinogen, factor VIII, and von Willebrand factor antigen levels, while other conventional coagulation test results were within reference intervals. Ten episodes of sMB (11.5%) were captured (3.0/100 person-years), with no significant association demonstrated between sMB and antiplatelet use (P = .36), platelet count (P = .14), or renal function (urea, P = .27; estimated glomerular filtration rate, P = .09). CKD patients with sMB had more hypocoagulable GCA parameters compared with those without sMB. The lowest quartiles of endogenous thrombin potential (subhazard ratio [sHR], 7.11; 95% CI, 1.84-27.45), overall hemostatic potential (sHR, 6.81; 95% CI, 1.77-26.16), and plasminogen activator inhibitor-1 (sHR, 5.26; 95% CI, 1.55-17.91) were associated with sMB.

Conclusion

This pilot study demonstrates that GCAs such as thrombin and fibrin generation may predict sMB risk in patients with CKD, which has potential to be practice-changing. Larger studies are required to validate these findings.

Thrombelastography Suggests Hypercoagulability in Patients with Renal Dysfunction and Intracerebral Hemorrhage

BACKGROUND

The objective of this study was to quantify coagulopathy using thrombelastography (TEG) in patients with renal dysfunction and intracerebral hemorrhage (ICH).

METHODS

We reviewed patients admitted with spontaneous ICH between November 2009 and May 2015. TEG was performed at the time of admission. Creatinine clearance (CCr) was calculated using the Cockroft-Gault equation. Patients were divided into 2 groups based on normal (CCr ≥ 90) or reduced renal function (CCr < 90). Multivariable regression models were conducted to compare the differences of TEG components.

RESULTS

A total of 120 patients were included in the analysis. The normal CCr group was younger (56.1 versus 62.3 years, P < .01), was more often male (73.6% versus 53.7%, P = .03), and had higher mean admission hemoglobin (14.2 versus 13.2 mEq/L, P < .01) than the reduced renal function group. The 2 groups were similar with respect to antiplatelet or anticoagulant use, coagulation studies, and baseline ICH volume. Following multivariate analysis, the reduced renal function group was found to have shorter K (1.5 versus 2.2 min, P = 004), increased angle (66 versus 62.2 degrees, P = .04), increased MA (67.3 versus 62.3, P = .02), and increased G (11.3 versus 9.9 dynes/cm², P = .04) compared with the normal group. Mortality, poor functional outcome (modified Rankin Scale score 4-6), hematoma enlargement, hospital length of stay, and surgical interventions were not different between the 2 groups.

CONCLUSIONS

Patients with ICH and reduced CCr display faster clotting rate and increased clot strength, suggesting that patients with renal dysfunction present with a relatively hypercoagulable state based on TEG parameters thought to reflect platelet activity.

Routine haemostasis testing before transplanted kidney biopsy: a cohort study

Kidney biopsy can result in bleeding complications. Prebiopsy testing using bleeding time (BT) is controversial. New whole blood haemostasis tests, such as platelet function analyser-100 (PFA-100) and multiple electrode aggregometry (MEA), might perform better. We postulated that PFA-100 would be suitable to replace BT prebiopsy. In 154 patients, transplanted kidney biopsies were performed after measurement of bleeding time, PFA-100, MEA and mean platelet volume (MPV). Bleeding outcome (haemoglobin (Hb) drop, haematuria (±bladder catheterization), ultrasound finding of a bleeding, need for (non)surgical intervention and/or transfusion) after the biopsy was correlated to each test. Male-female ratio was 2:1. 50% had a surveillance biopsy at either three or 12 months. Around 17% (had) used acetylsalicylic acid (ASA) prebiopsy. Of 17 bleeding events, one subject needed a transfusion. Most bleeding events were Hb reductions over 1 mmol/l and all resolved uneventful. BT, PFA-100, MEA and MPV did not predict a bleeding outcome; prior ASA use however could (odds ratio 3.19; 95%-CI 1.06 to 9.61). Diagnostic performance data and Bland-Altman analysis showed that BT could not be substituted by PFA-100. ASA use was the best determinant of bleeding after kidney biopsy. Routine haemostasis testing prebiopsy has no added value.

Hemostatic Abnormalities in Severe Renal Failure: Do They Bark or Bite?

Abnormal primary hemostasis is believed to be the most significant contributor to uremic bleeding. This study aimed to describe the prevalence and profile of primary and secondary hemostatic disorders in patients with chronic kidney disease (CKD) Stages 4 and 5 and to determine their association if any, with degree of uremia. Stages 4 and 5 predialysis CKD patients attending nephrology outpatient clinic were prospectively recruited and the following bleeding parameters were measured in all patients: platelet count, bleeding time (BT), Factor VIII assay, von Willebrand factor antigen (vWF:Ag), vWF:ristocetin cofactor activity (vWF:RCo), ratio of vWF:ristocetin cofactor activity to vWF antigen (vWF:RCo/vWF:Ag), prothrombin time (PT), and activated partial thromboplastin time (aPTT). Forty-five patients (80%, males) with a mean age of 39.4 years, 82% (n = 37) in Stage 5 CKD, were recruited for the study. The prevalence of thrombocytopenia was significantly higher among patients from West Bengal (15/26, 57.7%) compared to other study patients (2/19, 10.5%; P = 0.001); however, all had macrothrombocytes with normal BT, suggestive of the Harris syndrome. Factor VIII, vWF:Ag, vWF:RCo, vWF:RCo/vWF:Ag ratio, BT, PT, and aPTT were abnormal in 0 (0%), 0 (0%), 0 (0%), 4 (8.8%), 1 (2.2%), 7 (15.6%), and 5 (11.1%) patients, respectively. Except for thrombocytopenia, the prevalence of hemostatic abnormalities did not differ between CKD Stages 4 and 5. Hemostatic abnormalities are uncommon in Stages 4–5 CKD and except for thrombocytopenia, are not associated with degree of uremia. Constitutional macrothrombocytopenia is associated with normal BT even in CKD.

Renal dysfunction is an independent risk factor for bleeding after gastric ESD

BACKGROUND AND STUDY AIMS

The number of patients with chronic kidney disease (CKD) is increasing worldwide and gastric cancer sometimes occurs with CKD. However, the safety and feasibility of endoscopic submucosal dissection (ESD) for patients with CKD are not clear. The aim of this study is to clarify the feasibility and safety of gastric ESD for patients with CKD.

PATIENTS AND METHODS

This was a multicenter retrospective cohort study. In total, 144 patients with CKD who underwent gastric ESD between May 2003 and October 2012 were enrolled. The patients were divided into three groups: stage 3 (estimated glomerular filtration rate [eGFR]: 30 - 59 mL/min), stage 4 (eGFR: 15 - 29 mL/min), and stage 5 (eGFR: < 15 mL/min) according to the Kidney Disease Improving Global Outcomes Guidelines. The en bloc and curative resection rates and complications were assessed as short-term outcomes. Overall survival was analyzed using Kaplan - Meier methods.

RESULTS

In total, 92 patients were in stage 3 CKD; 23 in stage 4; and 29 in stage 5, including 19 patients in hemodialysis. The en bloc resection rate was 95.8 %. Post-ESD bleeding was observed in four patients with stage 5 CKD (13.8 %), three with stage 4 (13.0 %), and one with stage 3 (1.1 %). All bleeding could be controlled by endoscopic hemostasis, but five patients required blood transfusion. Perforation occurred in two patients (6.9 %) with stage 5 CKD, none (0 %) with stage 4, and two (4.3 %) with stage 3. Multivariate Poisson regression analysis revealed CKD stage 4 was a critical factor related to bleeding, whereas diabetes mellitus and CKD stage 5, which largely consist of patients receiving hemodialysis, were not. The median observation period of patients who achieved curative resection was 25.9 months (range 0.8-112.7 months) and the 3-year overall survival rate was 92.5 %.

CONCLUSIONS

Estimated GFR is a significant independent predictive factor of post-ESD bleeding in patients with CKD.

Haemostasis in chronic kidney disease

The coagulation system has gained much interest again as new anticoagulatory substances have been introduced into clinical practice. Especially patients with renal failure are likely candidates for such a therapy as they often experience significant comorbidity including cardiovascular diseases that require anticoagulation. Patients with renal failure on new anticoagulants have experienced excessive bleeding which can be related to a changed pharmacokinetic profile of the compounds. However, the coagulation system itself, even without any interference with coagulation modifying drugs, is already profoundly changed during renal failure. Coagulation disorders with either episodes of severe bleeding or thrombosis represent an important cause for the morbidity and mortality of such patients. The underlying reasons for these coagulation disorders involve the changed interaction of different components of the coagulation system such as the coagulation cascade, the platelets and the vessel wall in the metabolic conditions of renal failure. Recent work provides evidence that new factors such as microparticles (MPs) can influence the coagulation system in patients with renal insufficiency through their potent procoagulatory effects. Interestingly, MPs may also contain microRNAs thus inhibiting the function of platelets, resulting in bleeding episodes. This review comprises the findings on the complex pathophysiology of coagulation disorders including new factors such as MPs and microRNAs in patients with renal insufficiency.

Current practices of bleeding time in a developing country: an alert for noncompliance with the standard procedures

INTRODUCTION

Bleeding time is still widely performed in many developing countries including Thailand. To generate an accurate result, the procedure should be complied with standard recommendations such as those from Clinical and Laboratory Standards Institute (CLSI) and World Federation of Hemophilia (WFH). The authors surveyed the current practices of bleeding time in Thailand in order to verify the practices that did not comply with the accepted standard.

METHODS

The questionnaires were sent to hospitals participating Thailand National External Quality Assessment Scheme (NEQAS) for blood coagulation. Items in the questionnaire comprised information about preanalytical, analytical, and postanalytical issues of bleeding time.

RESULTS

From a dispatch of 201 questionnaires, 155 (77.1%) were returned. The common noncompliance with standards observed in this survey included inappropriateness of indication, e.g. use for preoperative screening (95 of 126, 75.4%), use of devices other than standard template (130 of 132, 98.5%), and inappropriate reference range (125 of 127, 98.4%).

CONCLUSIONS

The noncompliance shown in this survey can affect the accuracy of bleeding time results. The authors would like to address these problems as an alert for other laboratories especially in the developing countries where the standard templates are not widely available.