Bleeding time in uremia: a useful test to assess clinical bleeding

A Critical Reappraisal of the Bleeding Time

Seminars in Thrombosis and Hemostasis (STH) celebrates 50 years of publishing in 2024. To celebrate this landmark event, STH is republishing some archival material. This manuscript represents the second most highly cited paper ever published in STH. The manuscript published without an abstract, and essentially represented a State of the Art Review on the bleeding time, a relatively invasive procedure that required an incision on the skin or earlobe of a patient, and timing how long it took for the incision to stop bleeding. The bleeding time test was first described in 1901 by the French physician Milian, who presented three studies of bleeding from stab wounds made in the fingertips of healthy and diseased subjects. In 1910, Duke observed the duration of bleeding from small incisions of the ear lobe, and pointed out that the duration of bleeding was increased in instances of reduced platelet counts. The test was subsequently repeatedly modified, and numerous variants of the test, including semiautomated methods, were described by several workers. The most frequently utilised test reflected one described by Ivy and coworkers, who shifted the location of the incision to the volar aspect of the forearm and applied a blood pressure cuff to the arm to maintain a standard venous pressure. The bleeding time has been proposed for use as a diagnostic test for platelet-related bleeding disorders, a measure of efficacy in various forms of therapy, and as a prognosticator of abnormal bleeding. The authors to the current review reevaluated the bleeding time literature using methods to assess the performance of the test in 1990, locating 862 printed documents that discussed the bleeding time, the majority in peer-reviewed professional journals. As this is a republication of archival material, transformed into a modern format, we apologise in advance for any errors introduced during this transformation.

Cardiac Surgery Outcomes in Patients Receiving Hemodialysis Versus Peritoneal Dialysis

Rationale & Objective

We sought to compare outcomes of patients receiving dialysis after cardiothoracic surgery on the basis of dialysis modality (intermittent hemodialysis [HD] vs peritoneal dialysis [PD]).

Study Design

This was a retrospective analysis.

Setting & Participants

In total, 590 patients with kidney failure receiving intermittent HD or PD undergoing coronary artery bypass graft and/or valvular cardiac surgery at Cleveland Clinic were included.

Exposure

The patients received PD versus HD (intermittent or continuous).

Outcomes

Our primary outcomes were in-hospital and 30-day mortality. Secondary outcomes were length of stay, days in the intensive care unit, the number of intraoperative blood transfusions, postsurgical pericardial effusion, and sternal wound infection, and a composite of the following 4 in-hospital events: death, cardiac arrest, effusion, and sternal wound infection.

Analytical Approach

We used χ2, Fisher exact, Wilcoxon rank sum, and t tests, Kaplan-Meier survival, and plots for analysis.

Results

Among the 590 patients undergoing cardiac surgery, 62 (11%) were receiving PD, and 528 (89%) were receiving intermittent HD. Notably, 30-day Kaplan-Meier survival was 95.7% (95% CI: 93.9-97.5) for HD and 98.2% (95% CI: 94.7-100) for PD (P = 0.30). In total, 75 patients receiving HD (14.2%) and 1 patient receiving PD (1.6%) had a composite of 4 in-hospital events (death, cardiac arrest, effusion, and sternal wound infection) (P = 0.005). Out of 62 patients receiving PD, 16 (26%) were converted to HD.

Limitations

Retrospective analyses are prone to residual confounding. We lacked details about nutritional data. Intensive care unit length of stay was used as a surrogate for volume status control. Patients have been followed in a single health care system. The HD cohort outnumbered the PD cohort significantly.

Conclusions

When compared with PD, HD does not appear to improve outcomes of patients with kidney failure undergoing cardiothoracic surgery. Patients receiving PD had a lower incidence of a composite outcome of 4 in-hospital events (death, cardiac arrest, pericardial effusion, and sternal wound infections).

Bleeding Complications in Uremic Patients After Ultrasound-Guided Central Venous Catheter Placement

Introduction

Bleeding associated with elevated blood urea nitrogen (BUN) is a known complication. Patients with uremia require a central venous catheter insertion by dialysis. The relation between BUN and bleeding complications during central venous catheter insertion is not yet clear.

Objective

We described the frequency of complications associated with central venous catheter implantation in uremic patients and evaluated the statistical relationship between bleeding complications and catheter type, number of punctures, and catheter insertion site. Also, we determined if any value of BUN is associated with bleeding complications.

Methods

We included patients with a serum value of BUN >70 mg/dl that required insertion of a central venous catheter. The quantitative variables were expressed through the measure of central tendency. A bivariate analysis and a ROC curve were performed.

Results

A total of 273 catheters were included in this study. Bleeding complications were detected in 69 cases (25.3%), and local bleeding was the most frequent complication in 51/69 cases. Statistically significant association was not established. We did not find a specific cut-off value directly related to BUN levels and the rate of complications.

Conclusion

Bleeding complications associated with the insertion of central venous catheter and the suspected disorder of hemostasis given by BUN levels >70 mg/dl are common. It was not possible to determine a BUN cut-off value to predict complications. The association analysis was not conclusive. High BUN levels should not be considered a high-risk condition for central venous cannulation under ultrasound guidance performed by trained personnel.

Thromboelastography versus bleeding time for risk of bleeding post native kidney biopsy

Introduction

The risk of bleeding has led to screening of the primary hemostasis before renal biopsy. A bleeding time test (BT) is considered standard practice, but reliance on this test is controversial and its benefits remain questionable. A possible alternative is thromboelastography (TEG). However, data regarding TEG in patients with renal dysfunction is limited.

Objectives

To determine TEG abnormalities and their consequences in patients who underwent a native kidney biopsy.

Methods

A retrospective study of 417 consecutive percutaneous native renal biopsies performed in our Center. If serum creatinine >1.5 mg/dL, the patient underwent either a BT test (period A, January 2015–31 December 2016) or TEG (period B, January 2017–August 2018). In patients with prolonged BT, or an abnormal low maximal amplitude (MA) parameter of TEG, or suspected clinical uremic thrombopathy, the use of desmopressin acetate (DDAVP) was considered.

Results

Most biopsies (90.6%) were done by the same dedicated radiologist. Fifty-one patients had a BT test, which was normal in all tested patients. Seventy-one patients underwent TEG, and it was abnormal in 34 of them, most patients had combined abnormalities. The only parameter related to abnormal TEG was older age (Odds Ratio 1.21 [95% CI 1.09–2.38] p = 0.04 for abnormal Kinetics; OR 1.37 (1.05–1.96) p = 0.037 for abnormal MA). Twenty-six patients (6.23%) had bleeding complications. Risk of bleeding was significantly related to age (1.4 [1.11–7.48] p = 0.04), systolic blood pressure (1.85 [1.258–9.65] p = 0.02), and serum creatinine (1.21 [1.06–3.134] p = 0.048).

Conclusions

TEG abnormalities in patients with renal dysfunction are variable and fail to predict bleeding during kidney biopsy. The decision to administer DDAVP as a preventive measure during these procedures should be based on clinical judgment only.

Risk of incident bleeding after acute kidney injury: A retrospective cohort study

PURPOSE

End-stage kidney disease (ESKD) causes bleeding diathesis; however, whether these findings are extrapolable to acute kidney injury (AKI) remains uncertain. We assessed whether AKI is associated with an increased risk of bleeding.

METHODS

Single-center retrospective cohort study, excluding readmissions, admissions <24 h, ESKD or kidney transplants. The primary outcome was the development of incident bleeding analyzed by multivariate time-dependent Cox models.

RESULTS

In 1001 patients, bleeding occurred in 48% of AKI and 57% of non-AKI patients (p = .007). To identify predictors of incident bleeding, we excluded patients who bled before ICU (n = 488). In bleeding-free patients (n = 513), we observed a trend toward higher risks of bleeding in AKI (22% vs. 16%, p = .06), and a higher risk of bleeding in AKI-requiring dialysis (38% vs. 17%, p = .01). Cirrhosis, AKI-requiring dialysis, anticoagulation, and coronary artery disease were associated with bleeding (HR 3.67, 95%CI:1.33-10.25; HR 2.82, 95%CI:1.26-6.32; HR 2.34, 95%CI:1.45-3.80; and HR 1.84, 95%CI:1.06-3.20, respectively), while SOFA score and sepsis had a protective association (HR 0.92 95%CI:0.84-0.99 and HR 0.55, 95%CI:0.34-0.91, respectively). Incident bleeding was not associated with mortality.

CONCLUSIONS

AKI-requiring dialysis was associated with incident bleeding, independent of anticoagulant administration. Studies are needed to better understand how AKI affects coagulation and clinical outcomes.

Periprocedural Concerns in the Patient with Renal Disease

Treating patients with kidney disease can be both a difficult and a complex process. Understanding how to care for patients who have kidney disease is essential for lowering perioperative as well as periprocedural morbidity and mortality. The primary aim in renal evaluation and care is to control and mitigate factors that may result in acute kidney injury (AKI) and/or cause further decline in renal function. It is essential for the foot and ankle specialist to recognize patients who are predisposed to developing or already have impairment of renal function.

The in vitro Bleeding Time While Using a Stable Prostacyclin Analogue during Hemodialysis

A serious disadvantage of preventing clot formation by using prostacyclin (PGI2) to inhibit thrombocyte function during dialysis is that there exists no rapidly measurable monitoring parameter. The “in vitro bleeding time” fin vitro BT) is a new method for measuring primary hemostasis in vitro. Five chronic dialysis patients each underwent two dialyses: 1) with conventional full heparinization, and 2) with the stable PGI2 analogue CG 4203 and additional “low-dose” heparin. The predialytic in vitro BT is longer than normal values and values 1 h after the end of dialysis. While heparin has no significant effect on the in vitro BT, CG 4203 prolongs it concentration-dependently. Infusing CG 4203 at a rate of 25 ng/kg/min, the in vitro BT is extended beyond the measurable range of 800 μl during the first approx. 150 min of dialysis. During the next approx. 90 min it steadily decreases.

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.

Platelet aggregometry cannot identify uremic platelet dysfunction in heart failure patients prior to cardiac surgery

BACKGROUND

Patients with heart failure often have concomitant renal disease which can result in uremic platelet dysfunction. Determining whether uremia has affected platelets by platelet aggregometry can be challenging in these patients since they are often on antiplatelet medications. This study was undertaken to determine if platelet aggregation studies could identify heart failure patients at risk for uremic bleeding prior to cardiac surgery.

METHODS

Platelet aggregation studies from three groups were studied and compared: 17 heart failure patients with mild to moderate renal impairment, 17 heart failure patients without renal abnormalities and 17 healthy volunteers.

RESULTS

Platelet aggregation was severely impaired in both heart failure groups with and without renal abnormalities compared to healthy controls, and there were no significant differences in platelet aggregation in response to any of the agonists. There was a pan-decrease in platelet aggregation to all agonists in all heart failure patients.

CONCLUSION

Platelet aggregometry does not appear to be useful in measuring platelet dysfunction in heart failure patients with mild to moderate renal impairment.

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

INTRODUCTION

In patients with chronic kidney disease (CKD) predisposition to bleeding is frequently seen due to disturbances in platelet adhesion and aggregation. Various tests have been utilized to evaluate the disturbance of hemostasis in end-stage renal disease patients. In this trial; we evaluated skin bleeding time in patients admitted to our hospital with uremic symptoms and having hemodialysis (HD) for the first time. We also examined the effects of HD and uremia on this test and investigated its effectiveness in predicting the hemorrhagic complications before implementation of invasive procedures in uremic patients.

MATERIAL-METHOD

Twenty nine patients (13 men,16 women; mean age 59.7 ± 18.1) with CKD who presented with symptoms of uremia and treated with HD for the first time were enrolled in this trial. The skin bleeding time were measured before initiation of first hemodialysis and after the second hemodialysis session.

RESULTS

The skin bleeding time after the second dialysis was significantly shorter when compared to pre-dialysis values (p < 0.05). Correlation analysis between the skin bleeding time and urea, creatinine, hemoglobin, platelet, and bicarbonate showed no correlation.

CONCLUSIONS

Skin bleeding time could reveal the uremic platelet dysfunction and beneficial effect of dialysis in the patients who presented with uremic symptoms and treated with HD for the first time. We suggest that skin bleeding time may be an appropriate test for the evaluation of hemostasis disturbance in uremic patients and prediction of the bleeding risk before invasive procedures.

Thrombocytopenia in the Intensive Care Unit

Thrombocytopenia is a common laboratory finding in critically ill patients admitted to the intensive care unit. Potential etiologies of thrombocytopenia are myriad, ranging from acute disease processes and concomitant conditions to exposures and drugs. The mechanism of decreased platelet counts can also be varied: laboratory measurement may be spurious, platelet production may be decreased, or platelet destruction or sequestration may be increased. In addition to evaluation for the cause of thrombocytopenia, the clinician must also guard against spontaneous bleeding due to thrombocytopenia, prophylax against bleeding resulting from an invasive procedure performed in the setting of thrombocytopenia, and treat active bleeding related to thrombocytopenia.

Percutaneous renal biopsy of native kidneys: efficiency, safety and risk factors associated with major complications

INTRODUCTION

The use of an automated biopsy device and real-time ultrasound (current technology) for percutaneous renal biopsies (PRBs) has improved the likelihood of obtaining adequate tissue for diagnosis and has reduced the complications associated with renal biopsies. Our objective was to evaluate the efficacy and safety of the current PRB procedure and identify possible risk factors for the development of major complications.

MATERIAL AND METHODS

We collected all native kidney PRBs performed with current technology in our institute from January 1998 to April 2008. Studied variables were collected from the patient's chart at the time of the biopsy.

RESULTS

We analyzed 623 (96.4%) of 646 renal biopsies performed with the current automated procedure guided by real-time ultrasound. Although the effectiveness was 97.6%, there were 110 complications. Fourteen (2.24%) of these complications were major: 9 cases of renal hematoma, 2 cases with macroscopic hematuria (which needed blood transfusion), 1 case of intestinal perforation (which required exploratory laparotomy), 1 nephrectomy and 1 case of a dissecting hematoma. The logistic regression analysis demonstrated the following risk factors for developing major complications: diastolic blood pressure ≥ 90 mmHg, RR 7.6 (95% CI 1.35-43); platelet count ≤ 120×10(3)/µl; RR 7.0 (95% CI 1.9-26.2); and blood urea nitrogen (BUN) ≥ 60 mg/dl, RR 9.27 (95% CI 2.8-30.7).

CONCLUSIONS

The observed efficacy and safety of the current technique in the present study were similar to observations in previous studies. Diastolic blood pressure ≥ 90 mmHg, platelets ≤ 120×10(3)/µl and BUN ≥ 60 mg/dl were independent risk factors for the development of major complications following PRB.

Spontaneous renal hemorrhage in hemodialysis patients

Dialysis patients have a tendency to bleed, and clinicians sometimes encounter cases with a significant amount of spontaneous hemorrhage. We herein report two cases of spontaneous renal hemorrhage in hemodialysis patients.

Safe spinal anesthesia in a woman with chronic renal failure and placenta previa

Background:

Chronic renal failure is strongly associated with poor pregnancy outcome. Women dependent on hemodialysis before conception rarely achieve a successful live birth.

Case presentation:

A 31-year-old multiparous Turkish woman was scheduled for cesarean section under spinal anesthesia at 37 weeks and five days’ gestation because of hemorrhage due to secondary placenta previa. Spinal anesthesia with 8 mg of hyperbaric bupivacaine was successfully performed. Invasive blood pressure, central venous pressure, and heart rate were stable during the surgery. The mother returned to regular hemodialysis on the first postoperative day.

Conclusion:

Pregnancy is uncommon in women with chronic renal failure requiring chronic dialysis. Rates of maternal hypertension, pre-eclampsia, anemia, and infection in the pregnant chronic dialysis patient are high. However, our findings suggest that with careful, close, and effective monitoring preoperatively and intraoperatively, spinal anesthesia can be safely performed for cesarean section in patients undergoing hemodialysis.

Perioperative management of patients with renal disease

The patient who has renal disease is susceptible to many potential complications during the perioperative period. The prevention of postoperative acute renal failure (ARF), especially in patients who have existing chronic kidney disease, and management of patients who have end-stage renal disease (ESRD) who are undergoing surgery are challenging. Elimination of risk factors for ARF and early diagnosis of ARF should improve patient outcomes. For patients who have ESRD, a thorough and comprehensive evaluation is necessary to decrease morbidity and mortality associated with the end-organ damage. This article reviews the prevention of postoperative ARF and the perioperative management of patients who have ESRD who are undergoing surgery.

Diabetes, vascular complications and antiplatelet therapy: open problems

Diabetes mellitus is commonly associated with both microvascular and macrovascular complications (coronary artery disease, cerebrovascular events, severe peripheral vascular disease, nephropathy and retinopathy). There is wide evidence demonstrating that platelet degranulation and synthesis of TxA2 are increased in diabetic patients. For this reason, many studies on anti-platelet therapy have been made to reduce thrombotic complication of diabetes mellitus. Some diabetic patients, although treated with ASA, have a high prevalence of recurrent thrombotic events, which may presumably be due to an "ASA resistance". Nevertheless, this drug remains the one with the greatest benefit. To optimize its function, we should try to understand the causes of "aspirin resistance", try to find the most suitable dosage, recommending patients to comply constantly with the prescription given and to avoid interactions with other drugs. "Clopidogrel resistance" is a term not clearly defined. The clinical implications of "clopidogrel resistance" are unknown. An important consideration affecting the use of aspirin in diabetic patients is its interaction with ACE-inhibitors. Another question is antiplatelet therapy in nephropathic diabetic patients. Although these patients are at high thrombotic and haemorrhagic risk, they should nevertheless be considered eligible to undergo antithrombotic therapy, taking into account the individual's haemorrhagic risk.

Complications of arteriovenous hemodialysis access: recognition and management

English language citations reporting complications of arteriovenous access for hemodialysis are critically reviewed and discussed. Venous hypertension, arterial steal syndrome, and high-output cardiac failure occur as a result of hemodynamic alterations potentiated by access flow. Uremic and diabetic neuropathies are common but may obfuscate recognition of potentially correctable problems such as compression or ischemic neuropathy. Mechanical complications include pseudoaneurysm, which may develop from a puncture hematoma, degeneration of the wall, or infection. Dysfunctional hemostasis, hemorrhage, noninfectious fluid collections, and access-related infections are, in part, manifestations of the adverse effects of uremia on the function of circulating hematologic elements. Impaired erythropoiesis is successfully managed with hormonal stimulation; perhaps, similar therapies can be devised to reverse platelet and leukocyte dysfunction and reduce bleeding and infectious complications.

Post-sphincterotomy bleeding: who, what, when, and how

Endoscopic biliary sphincterotomy (ES) is the cornerstone of therapeutic endoscopic retrograde cholangiopancreatography (ERCP). Bleeding is one of the most frequent complications following ES. Rates of post-ES bleeding vary widely and its presentation may be immediate (intraprocedural) or several days later. Clinically, bleeding can range from insignificant to life threatening. Most bleeding episodes are managed successfully by conservative measures with or without endoscopic therapy. Endoscopic treatment options include injection, thermal, and mechanical methods-alone or in combination. For refractory cases, angiographic embolization, or surgery, is necessary. Both technical risk factors and patient risk factors contribute to the development of post-ES bleeding. When these risk factors are present, measures can be taken to reduce the risk of bleeding. In this manuscript the literature on post-ES bleeding is reviewed.

Evidence-based treatment recommendations for uremic bleeding

Uremic bleeding syndrome is a recognized consequence of renal failure and can result in clinically significant sequelae. Although the pathophysiology of the condition has yet to be fully elucidated, it is believed to be multifactorial. This article is a review of both the normal hemostatic and homeostatic mechanisms that operate within the body to prevent unnecessary bleeding, as well as an in-depth discussion of the dysfunctional components that contribute to the complications associated with uremic bleeding syndrome. As a result of the multifactorial nature of this syndrome, prevention and treatment options can include one or a combination of the following: dialysis, erythropoietin, cryoprecipitate, desmopressin, and conjugated estrogens. Here, these treatment options are compared with regard to their mechanism of action, and onset and duration of efficacy. An extensive review of the clinical trials that have evaluated each treatment is also presented. Lastly, we have created an evidence-based treatment algorithm to help guide clinicians through most clinical scenarios, and answered common questions related to the management of uremic bleeding.

[Thrombocytopathy and blood complications in uremia]

Bleeding diathesis and thrombotic tendencies are characteristic findings in patients with end-stage renal disease. The pathogenesis of uremic bleeding tendency is related to multiple dysfunctions of the platelets. The platelet numbers may be reduced slightly, while platelet turnover is increased. The reduced adhesion of platelets to the vascular subendothelial wall is due to reduction of GPIb and altered conformational changes of GPIIb/IIIa receptors. Alterations of platelet adhesion and aggregation are caused by uremic toxins, increased platelet production of NO, PGI(2), calcium and cAMP as well as renal anemia. Correction of uremic bleeding is caused by treatment of renal anemia with recombinant human erythropoietin or darbepoetin alpha, adequate dialysis, desmopressin, cryoprecipitate, tranexamic acid, or conjugated estrogens. Thrombotic complications in uremia are caused by increased platelet aggregation and hypercoagulability. Erythrocyte-platelet-aggregates, leukocyte-platelet-aggregates and platelet microparticles are found in higher percentage in uremic patients as compared to healthy individuals. The increased expression of platelet phosphatidylserine initiates phagocytosis and coagulation. Therapy with antiplatelet drugs does not reduce vascular access thrombosis but increases bleeding complications in endstage renal disease patients. Heparin-induced thrombocytopenia (HIT type II) may develop in 0-12 % of hemodialysis patients. HIT antibody positive uremic patients mostly develop only mild thrombocytopenia and only very few thrombotic complications. Substitution of heparin by hirudin, danaparoid or regional citrate anticoagulation should be decided based on each single case.

The effect of uremia on platelet contractile force, clot elastic modulus and bleeding time in hemodialysis patients

INTRODUCTION

Uremic bleeding frequently occurs in dialysis patients. Although its mechanism is not well characterized, acquired platelet dysfunction has been implicated in its pathogenesis. Skin bleeding time has been used to characterize platelet dysfunction in this population. However, the bleeding time is prone to error. The goal of this study was to compare the bleeding time to the novel platelet function parameters platelet contractile force and clot elastic modulus as well as platelet aggregation studies in controls and patients receiving maintenance hemodialysis.

MATERIALS AND METHODS

Forty-five subjects completed this study (25 controls, 20 dialysis). All subjects had the Ivy skin bleeding time procedure performed, as well as the collection of whole blood samples for the determination of platelet contractile force, clot elastic modulus, % von Willebrand Factor antigen, and platelet aggregation studies. Pearson's correlation determined the relationships between skin bleeding time and platelet function and clot structure parameters and markers of renal dysfunction.

RESULTS

Bleeding time was significantly prolonged in the dialysis group relative to controls. The platelet function parameters were not significantly different between groups. There was a significant relationship between bleeding time and creatinine concentration, however, no relationship existed between bleeding time and platelet function parameters.

CONCLUSIONS

Skin bleeding time poorly correlates with measurements of platelet function. There were no significant differences noted in platelet function between the groups despite the prolongations in bleeding time in the dialysis group. These data may suggest that the bleeding time reflects perturbations in platelet adhesion or secretion, and not aggregation. Further study is needed to characterize platelet function in dialysis patients.

Plasma levels of plasminogen activator inhibitor type 1, factor VIII, prothrombin activation fragment 1+2, anticardiolipin, and antiprothrombin antibodies are risk factors for thrombosis in hemodialysis patients

Patients with end-stage renal disease are prone to hemorrhagic complications and simultaneously are at risk for a variety of thrombotic complications such as thrombosis of dialysis blood access, the subclavian vein, coronary arteries, cerebral vessel, and retinal veins, as well as priapism. The study was devised for the following purposes: (1) to identify the markers of thrombophilia in hemodialyzed patients, (2) to establish a role for antiphospholipid antibodies in thrombosis of the vascular access, (3) to characterize phospholipid antibodies in hemodialysis patients, and (4) to study the effects of dialysis on coagulation cascade. A group of 20 hemodialysis patients with no thrombotic complications (NTC) and 20 hemodialysis patients with thrombotic complications (TC) were studied along with 400 volunteer blood donors. Patients with systemic lupus erythematosus and those with nephrotic syndrome were excluded. All patients underwent a screening prothrombin time, activated partial thromboplastin time, fibrinogen (Fg), coagulation factors of the intrinsic and extrinsic pathways, antithrombin III (AT-III), protein C (PC), protein S (PS), resistance to activated protein C, prothrombin activation fragment 1+2 (F1+2), plasminogen, tissue type plasminogen activator (t-PA), plasminogen tissue activator inhibitor type-1 (PAI-1), anticardiolipin antibodies type M and G (ACA-IgM and ACA-IgG), lupus anticoagulant antibodies, and antiprothrombin antibodies type M and G (aPT-IgM and aPT-IgG). The study showed that PAI-1, F 1+2, factor VIII, ACA-IgM, and aPT-IgM levels were increased significantly over controls both in TC and NTC, however, they could distinguish patients with thrombotic complications from those without, being increased maximally in the former group. The novelty of the study is represented by the significant aPT increase that was observed in non-systemic lupus erythematosus hemodialysis patients, and particularly in those with thrombotic events. In addition, there was a reduction of factor XII during the treatment. It is possible to assume in the TC group and, to a lesser extent, also in the NTC group that endothelial cells liberate PAI-1 in the vascular lumen, which causes hypofibrinolysis. In addition, an excess of factor VIII is activated by endothelial dysfunction with subsequent activation of the coagulation cascade as shown by increased F1+2 and fibrinogen. ACA-IgM, in turn, is capable of interfering with the system of protein C, a potent anticoagulant factor that inactivates cofactors Va and VIIIa. They also induce the expression of procoagulant factors on the surface of the endothelial cells. In conclusion, the hypercoagulable state caused by alterations of coagulation and fibrinolytic factors is a cause of vascular access dysfunction and thrombosis of other vessels.

[Dilatation of the papilla of Vater in the treatment of choledocholithiasis in selected patients]

OBJECTIVE

To prospectively analyze the results obtained with papillary balloon dilatation (PBD) in the treatment of common bile duct stones in patients at risk of complications if endoscopic sphincterotomy (ES) were performed.

PATIENTS AND METHOD

Thirty-three patients were included between January 2001 and June 2003 (mean age 76.2 years). The criteria for PBD were: choledocholithiasis < or =10 mm in patients with peripapillary diverticula, hemostatic alterations, Billroth-II, and preservation of Oddi's sphincter. In 79% of the patients sedation was performed by an anesthetist. PBD was performed with a balloon catheter dilator with a diameter of 8 or 10 mm for 2 minutes. The efficacy and duration of the procedure as well as complications at 30 days and patient satisfaction were evaluated.

RESULTS

Stone extraction was achieved in all patients (100%). The mean duration of the procedure was 26 minutes. Two patients (6%) presented mild pancreatitis. Serum amylase was elevated in 16 patients (48%): > or =3 times (post-PBD hyperamylasemia) in 11 (33%). The procedure caused no discomfort in 25/26 (96%) of the patients sedated by an anesthetist vs 2/5 patients (49%) who underwent endoscopic sedation.

CONCLUSIONS

PBD is an effective and simple therapeutic option in the treatment of small common bile duct stones (< or =10 mm) and in patients at high risk. The duration of endoscopic retrograde cholangiopancreatography is not prolonged. Complications are infrequent (6%) and mild. Post-PBD hyperamylasemia is frequent and generally without clinical importance. Sedation by an anesthetist improves patient satisfaction.

Perioperative management of patients with chronic kidney disease or ESRD

The perioperative management of patients with chronic kidney disease (CKD) or dialysis-dependent end-stage renal disease (ESRD) is complicated by both the underlying renal dysfunction, with associated disturbances of fluid and electrolyte homeostasis and altered drug clearance, and the presence of associated co-morbid conditions, including diabetes mellitus, chronic hypertension and cardiovascular and cerebrovascular disease. The impact of CKD on fluid and electrolyte management, haematological and cardiovascular complications and drug management in the perioperative period are reviewed. Special issues related to the management of haemodialysis and peritoneal dialysis patients in the perioperative period are also reviewed.

Utility of in vitro closure time test for evaluating platelet-related primary hemostasis in dialysis patients

BACKGROUND

The platelet aggregation and skin bleeding time (SBT) tests currently used for assessment of hemostasis impairment in dialysis patients have important disadvantages. The authors explored the utility of a novel in vitro closure time test (PFA-100, platelet function analyzer) in which the process of platelet adhesion and aggregation after vascular injury is simulated in vitro in dialysis patients.

METHODS

Thirty-four long-term dialysis patients were included in the study with 30 healthy volunteers as the control group. In vitro closure time was compared with results from the platelet aggregation and SBT tests.

RESULTS

In vitro closure time identified more patients and fewer controls with hemostasis impairment. In the patient group, 60%, 40%, and 20%, and in the control group, 0%, 10% and 3% of persons were found to have hemostasis impairment as determined by in vitro closure time, platelet aggregation, and SBT, respectively. In addition, values for patients and controls were significantly different for in vitro closure time (P < 0.05) but not for platelet aggregation or SBT. Thus, closure time appears to be more sensitive and specific than the other 2 tests. No correlation was found between the 3 tests, either in patients or in controls. However, a high correlation (r = 0.73; P < 0.0001) was found between the 2 types of in vitro closure time test (collagen/epinephrine [CEPI] and collagen/adenosine diphosphate [CADP]) in patients and controls.

CONCLUSION

These results indicate that in vitro closure time can be a useful test for detecting platelet-related primary hemostasis defects in dialysis patients.

The effect of IM ketorolac tromethamine on bleeding time: a prospective, interventional, controlled study

Opiates, although effective analgesics, have significant adverse side effects. Ketorolac, the only parental nonsteroidal antiinflammatory drug available for use in the United States does not cause significant respiratory depression or hypotension, but it is a reversible inhibitor of platelet aggregation with a theoretical increased bleeding risk, which limits its use. The objective of this study was to determine the effect of a single intramuscular dose of 60 mg ketorolac on 4-hour bleeding times in healthy volunteers. This was a prospective, paired, unblinded, before-and-after interventional study performed in a suburban university-based EM residency training program. Subjects were 20 healthy volunteer EM residents. Standard Ivy bleeding times were measured before and 4 hours after intramuscular administration of 60 mg ketorolac. Before-and-after bleeding times were compared using a paired t-test. The study had 90% power to detect an effect size of 0.5. The subjects' mean age was 31.6 and 7 (35%) were females. Bleeding time was increased from a mean baseline time of 3 minutes 34 seconds (+/- 1 min 20 sec) to a mean 4-hour postinjection time of 5 minutes 20 seconds (+/- 3 min 8 sec). The mean prolongation of bleeding time was 1 minute 46 seconds (50% increase with 95% confidence interval, 25%-75%). There were no adverse events. A standard intramuscular dose of 60 mg ketorolac resulted in prolongation of the bleeding time in healthy volunteers. The clinical significance of this prolongation in patients is unclear.

Review of antithrombotic agents used for acute coronary syndromes in renal patients

Management issues in acute coronary syndromes (ACSs) with regard to patients with renal insufficiency or failure are complex. Renal patients have a greater risk for bleeding compared with those with normal renal function because of prolonged bleeding time and platelet dysfunction. Some of the drugs used have significant renal excretion, such as the glycoprotein IIb/IIIa receptor antagonists. Additionally, thrombolytics are underused, which contributes to the delay in instituting immediate treatment of acute myocardial infarction. Clinical data regarding the optimum management of ACSs in renal patients are still lacking. In this article, we review the available data on the use of antithrombotic agents, particularly in patients with renal impairment.

Pharmacokinetics and antidiuretic effect of high-dose desmopressin in patients with chronic renal failure

High-dose desmopressin shortens the bleeding time in uraemia. The aim of this study was to investigate the pharmacokinetics and the antidiuretic effect of desmopressin when given in a dose normally used for haemostasis to patients with reduced renal function. Ten patients with chronic renal failure of varying aetiology were enrolled in the study. The age was 58 (20-76) years (median and range), serum creatinine 447 (309-691) micromol/l and plasma clearance of iohexol 16 (8-19) ml/min./1.73 m2 body surface. After baseline measurements, desmopressin was infused at a dose of 0.3 microg/kg. The plasma concentration of desmopressin was followed for 26 hr during and after the infusion and the pharmacokinetic parameters were estimated by compartmental analysis. Urine volume and osmolality, as well as body weight, blood pressure, heart rate, haematocrit, serum osmolality, electrolytes and creatinine, were measured repeatedly during the day before and for two days after the infusion. The total clearance of desmopressin was 0.35 (0.21-0.47) ml/min./kg, the volume of distribution at steady state was 0.30 (0.17-0.38) l/kg and the terminal half-life 9.7 (8.4-16) hr. After administration of desmopressin, urine osmolality increased significantly, by approximately 10%, and this increase lasted for 48 hr. Concomitantly, there was a modest but significant decrease in haematocrit. Thus, the clearance of desmopressin was on average decreased to approximately one quarter, and the terminal half-life was prolonged 2-3 times in the patients as compared to previously published values for healthy adults. The single haemostatic dose of desmopressin given to patients with severe renal failure did not cause fluid overload or changes in serum electrolytes.

Should Aspirin Therapy be Withheld before Insertion and/or Removal of a Permanent Peritoneal Dialysis Catheter?

The necessity of withdrawal of aspirin [acetylsalicylic acid (ASA)] for fear of perioperative or postoperative bleeding in patients about to undergo surgery is as yet controversial. In this study we prospectively evaluated the effect of ASA on postoperative bleeding in end-stage renal failure patients who underwent insertion, removal, and/or replacement of a peritoneal dialysis (PD) catheter at our institution from November 1999 to March 2001. During the study period 52 of the above procedures were consecutively performed in 46 patients. Patients whose catheters were removed as a result of refractory peritonitis were excluded from the study. In all cases the PD catheter used was the coiled two-cuff Tenckhoff (NIPRO™, Manchester, GA) catheter and the surgery was performed in the operating room under local anesthesia. No drains were left in the operating wound. Postoperative bleeding (wound hematoma or persistent oozing from the incision or exit site) was classified as either minor (requiring no professional intervention and/or blood replacement) or major [necessitating blood transfusion (≥1 unit red blood cells). Of the 52 procedures 29 (in 24 patients) were performed while the patient was receiving aspirin at the time of operation (aspirin group). The remaining 23 were without aspirin and constituted the control group. ASA dose was 100 mg/day in all but three who were on buffered ASA (325 mg/day). The groups were well matched with regard to age; sex; mean residual renal function; and preoperative international normalized ratio, activated partial thromboplastin time, and platelet count. In no case was there significant intraoperative bleeding. There were five (17.2%) and three (13.0%) minor bleeds in the aspirin group and control group, respectively. One major bleed occurred in the control group ending in an exploratory laparotomy. Of the nine bleeding complications six were observed after catheter removal. From these data we conclude that PD catheter insertion/removal can be safely performed under conventional low-dose aspirin therapy.

Benefits of aspirin and beta-blockade after myocardial infarction in patients with chronic kidney disease

BACKGROUND

There have been no randomized trials of cardioprotective therapy after acute myocardial infarction in patients with chronic kidney disease who should be largely eligible for aspirin (acetylsalicylic acid; ASA) and beta-blockers (BB) as a base of therapy.

METHODS

We analyzed a prospective coronary care unit registry of 1724 patients with ST-segment elevation myocardial infarction.

RESULTS

Usage rates were 52.3%, 19.0%, 15.2%, and 13.5% for ASA and BB (ASA+BB), BB alone, ASA alone, and no ASA or BB therapy. Patients who received ASA+BB were more likely to be male, free of earlier cardiac disease, and recipients of thrombolysis. Conversely, the absence of ASA+BB was observed in patients with heart failure on admission, left bundle branch block, atrial and ventricular arrhythmias, and shock. The combination of ASA+BB was used in 63.9%, 55.8%, 48.2%, and 35.5% of patients with corrected creatinine clearance values of >81.5, 81.5 to 63.1, 63.1 to 46.2, and <46.2 mL/min/72 kg (P <.0001). ASA+BB was used in 40.4% of patients undergoing dialysis. The age-adjusted relative risk reduction for the inhospital mortality rate was similar among all renal groups and ranged from 64.3% to 80.0% (all P <.0001).

CONCLUSION

ASA+BB is an underused therapy in patients with acute myocardial infarction who have underlying kidney disease.

17beta-estradiol corrects hemostasis in uremic rats by limiting vascular expression of nitric oxide synthases

Conjugated estrogens shorten the prolonged bleeding time in uremic patients and are similarly effective in a rat model of uremia. We have previously demonstrated that the shortening effect of a conjugated estrogen mixture or 17beta-estradiol on bleeding time was abolished by the nitric oxide (NO) precursor L-arginine, suggesting that the effect of these drugs on hemostasis in uremia might be mediated by changes in the NO synthetic pathway. The present study investigated the biochemical mechanism(s) by which conjugated estrogens limit the excessive formation of NO. 17beta-estradiol (0.6 mg/kg), given to rats made uremic by reduction of renal mass, significantly reduced bleeding time within 24 h and completely normalized plasma concentrations of the NO metabolites, nitrites and nitrates, and of NO synthase (NOS) catalytic activity, determined by NADPH-diaphorase staining in the thoracic aorta. Endothelial NOS (ecNOS) and inducible NOS (iNOS) immunoperoxidase staining in the endothelium of uremic aortas of untreated rats was significantly more intense than in control rats, while in uremic rats receiving 17beta-estradiol staining was comparable to controls. Thus 17beta-estradiol corrected the prolonged bleeding time of uremic rats and fully normalized the formation of NO by reducing the expression of ecNOS and iNOS in vascular endothelium. These results provide a possible biochemical explanation of the well-known effect of estrogens on primary hemostasis in uremia, in experimental animals and humans.

Is the bleeding time predictive of bleeding prior to a percutaneous renal biopsy?

The bleeding time is used by many nephrologists to predict risk of hemorrhage before percutaneous kidney biopsy. Developed in 1910, the bleeding time is a nonspecific test that may be prolonged in multiple disease states. When accompanied by a platelet count, hematocrit, and a thorough investigation of family or personal history of bleeding, the bleeding time is the best predictor of hemorrhagic risk in patients with kidney disease. Because there is a small but significant risk of bleeding with percutaneous kidney biopsy, a prolonged bleeding time should be treated with 1-deamino-8-D-arginine vasopressin, cryoprecipitate, estrogens, or dialysis as indicated before biopsy. Treating all patients with 1-deamino-8-D-arginine vasopressin without checking bleeding times may be cost-ineffective when compared with treating only those patients with prolonged bleeding times.

Uremic bleeding: pathogenesis and therapy

BACKGROUND

We reviewed current understanding of the pathophysiology of the uremic bleeding diathesis and discuss accepted therapeutic interventions that minimize the risk of bleeding in the uremic patient.

METHODS

Computerized literature searches and references from previous publications, including articles describing original research and reviews pertaining to the pathophysiology of and clinical approach to uremic bleeding.

RESULTS

The most common hemorrhagic manifestations in uremia are prolonged bleeding from puncture sites; nasal, gastrointestinal and genitourinary bleeding; and subdural hematomas. The most useful clinical laboratory test to assess both bleeding risk and response to therapy is bleeding time. It correlates better with clinical bleeding complications than indices of azotemia (eg, blood urea nitrogen [BUN], creatinine) or in vitro platelet aggregation tests. A low hematocrit is also correlated with increased bleeding risk. Anemia plays an important role in the bleeding diathesis of uremia and its correction with red cell transfusions or human recombinant erythropoietin is critical. Anticoagulation during hemodialysis may transiently exacerbate the bleeding diathesis. Hemodialysis and peritoneal dialysis improve the hemostatic defect and renal transplantation totally corrects it. Cryoprecipitate has been largely replaced by desmopressin acetate, which acts promptly (in less than 1 hour) but has a short duration of action (hours) and exhibits tachyphylaxis. Conjugated estrogens are slower in the onset of action (about 6 hours) but their effect lasts for about 2 weeks.

CONCLUSIONS

The pathophysiology of the bleeding diathesis of uremia is complex and incompletely understood but useful clinical tests and therapies have evolved empirically. Broadly available dialysis and the advent of erythropoietin are likely to reduce the magnitude of this problem.