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

Multidirectional Effects of Tormentil Extract on Hemostasis in Experimental Diabetes

In our previous study, we showed that ellagitannin- and procyanidin-rich tormentil extract (TE) decreased experimental arterial thrombosis in normoglycemic rats through platelet inhibition. TE also slightly increased coagulation and attenuated fibrinolysis; however, these effects did not nullify the antithrombotic effect of TE. The present study aimed to assess whether TE exerts antithrombotic activity in streptozotocin (STZ)-induced diabetes, which is characterized by pre-existing increased coagulation and impaired fibrinolysis, in vivo and ex vivo thrombosis assays. TE (100, 200, or 400 mg/kg, p. o.) was administered for 14 days to STZ-induced diabetic rats and mice. TE at 100 mg/kg dose decreased the thrombus area in the mice model of laser-induced thrombosis through its potent antiplatelet effect. However, TE at 200 mg/kg dose increased thrombus weight in electrically induced arterial thrombosis in rats. The prothrombotic effect could be due to increased coagulation and attenuated fibrinolysis. TE at 400 mg/kg dose also improved vascular functions, which was mainly reflected as an increase in the arterial blood flow, bleeding time prolongation, and thickening of the arterial wall. However, TE at 400 mg/kg dose did not exert antithrombotic effect. Summarizing, the present results show that TE may exert multidirectional effects on hemostasis in STZ-induced diabetic rats and mice. TE inhibited platelet activity and improved endothelial functions, but it also showed unfavorable effects by increasing the activity of the coagulation system and by inhibiting fibrinolysis. These contrasting effects could be the reason for model-specific influence of TE on the thrombotic process in STZ-induced diabetes.

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.

Desmopressin (Octostim®) before a native kidney biopsy can reduce the risk for biopsy complications in patients with impaired renal function: A pilot study

AIM

To evaluate whether the administration of desmopressin alters the risk for renal biopsy complications.

METHODS

A multicenter registry containing 576 native kidney biopsies (NKb) with a serum creatinine above 150 μmol/L in 527 patients (372 men and 155 women, median age 61 years) was used. Most of the data were prospective. At one of the hospitals all biopsies with creatinine above 150 μmol/L received desmopressin before biopsies (NKb 204). These were compared to outcome of biopsy complications against other centres where desmopressin was not given (NKb 372). Fisher's exact test, χ² analyses, univariate and multiple binary logistic regression were used. Data were given as odds ratio (OR) and confidence interval (CI). A two sided P-value of <0.05 was considered significant.

RESULTS

In NKb with creatinine >150 μmol/L, those with desmopressin had less overall (3.4% vs 8.4%, OR 0.39, CI 0.17-0.90) whereas major or minor complications were not different. While desmopressin did not exhibit difference in complications in men, women received less major (0% vs 8.6%, P = 0.03) and overall complications (0% vs 12.1%, P = 0.006). A multiple logistic regression revealed that, after adjusting for BMI, age and sex, prophylaxis with desmopressin showed less major (OR 0.38, CI 0.15-0.96) and overall complications (OR 0.36, CI 0.15-0.85).

CONCLUSION

Desmopressin given before a native kidney biopsy in patients with impaired renal function can reduce the risk for complications.

Complications of the percutaneous kidney biopsy

Percutaneous kidney biopsy is an integral part of a nephrologist's practice. It has helped to define nephrology as a subspecialty. When indicated, it is a necessary procedure to help patients, as it allows for diagnostic, prognostic, and therapeutic information. Although very safe, this procedure can give rise to complications, mainly related to bleeding. Since its development in the 1950s, modifications have been made to the approach and the technique, which have improved the diagnostic yield while keeping it a safe procedure. Alterations to the standard approach may be necessary if risk factors for bleeding are present. In addition, obesity, pregnancy, and solitary kidney biopsy are all special circumstances that change the procedure itself or the risk of the procedure. Today, kidney biopsy is a vital procedure for the nephrologist: clinically relevant, safe, and effective.

Treatment of bleeding in dialysis patients

Bleeding is a common and potentially serious complication of acute and chronic renal failure. The pathogenesis of bleeding in uremia is multifactorial; however, the major role is played by abnormalities in platelet-platelet and platelet-vessel wall interaction. Platelet dysfunction is partially due to uremic toxins present in circulating blood. Despite decreased platelet function, abnormalities of blood coagulation and fibrinolysis predispose the uremic patients to a hypercoagulable state carrying the risk of cardiovascular and thrombotic complications. Dialysis improves platelet abnormalities and reduces, but does not eliminate, the risk of hemorrhage. Hemodialysis can even contribute to the bleeding through the continuous platelet activation induced by the interaction between blood and artificial surfaces and the use of anticoagulants. Correction of anemia improves hemostasis in uremic patients. Therapeutic management of bleeding in patients with uremia is discussed.

The value of post-biopsy ultrasound in predicting complications after percutaneous renal biopsy of native kidneys

BACKGROUND

Clinically significant bleeding complications occur in >30% of patients undergoing percutaneous renal biopsy (PRB) of native kidneys and can be severe in up to 10% of patients. A noninvasive measure that would reliably predict which patients will do well with an uncomplicated post-biopsy course or which patients may be at risk of developing a clinically significant complication is in great demand.

METHODS

PRB of native kidneys was performed in 162 adult patients from February 2002 through February 2007 using real-time ultrasound and automated needle. Renal ultrasound (US) was performed at 1-h post-PRB to assess biopsy-related bleeding. Patients were observed for 24 h post-PRB to monitor clinically apparent biopsy-related complications. The value of the post-biopsy ultrasound in predicting complications was assessed.

RESULTS

A clinically apparent complication was observed in 26 (16%) patients post-PRB (13 minor not requiring any intervention and 13 major requiring intervention). In patients with complicated courses, a haematoma at 1 h was seen in 77% (69% with minor and 87% with major complications). However, only 27 (20%) of 136 patients without complications (P < 0.0001) had a haematoma at 1 h. The presence of a haematoma 1-h post-PRB had a sensitivity of 77%, specificity of 80%, positive predictive value of 43% but a negative predictive value of 95% for predicting clinical complications.

CONCLUSIONS

We find that with the use of renal ultrasound 1-h post-PRB, the absence of perinephric bleeding is predictive of an uncomplicated course while the presence of a perinephric haematoma is not reliably predictive of a clinically significant complication post-renal biopsy.

Use of the platelet function analyzer to minimize bleeding complications after renal biopsy

BACKGROUND

The bleeding time is frequently used to screen primary haemostasis before surgical procedures, although it poorly predicts the risk of hemorrhage. The platelet function analyzer (PFA), which is also used to screen primary haemostasis, has a higher sensitivity and other advantages, like patient friendliness, higher degree of objectivity and analytical reliability, but needs more extensive clinical validation.

METHODS

We compared the predictive values of the PFA-CTs (closure times) and bleeding time for bleeding events after renal biopsy. We prospectively evaluated the complications in patients that underwent a renal biopsy and were screened with PFA in advance (n=170). For comparison we used a historical cohort of patients screened with the bleeding time (n=132).

RESULTS

When the PFA-CTs were normal, 26.0% of the patients had a mild bleeding event after the biopsy, which did not differ from the event rate with a normal bleeding time (29.4%). When one or both PFA-CTs were prolonged, 51.3% of the patients had post-biopsy bleeding events independently of the measures to correct the closure time(s), significantly more than with either a prolonged bleeding time (26.7%) or normal PFA-CTs (26.0%).

CONCLUSION

For bleeding events, the PFA has a higher positive and similar negative predictive value compared to the bleeding time. Taken into account the additional advantages of the PFA like patient friendliness and better analytical qualities, we prefer the PFA over the bleeding time as a screening tool for primary haemostasis before performing a renal biopsy.

Is it necessary to stop antiplatelet agents before a native renal biopsy?

BACKGROUND

The practice of advising patients to stop antiplatelet agents before an elective renal biopsy is widespread. The aim of this study was to compare the rate of bleeding complications in two centres that have different policies regarding the ongoing use of antiplatelet agents in patients undergoing an elective renal biopsy. Neither centre routinely checks bleeding time before renal biopsy. A secondary aim, therefore, was to compare complication rates from this cohort with those reported in the literature where screening for prolonged bleeding time is standard practice.

METHODS

A retrospective study of 1120 biopsies performed by nephrologists under direct ultrasound guidance in the two renal units in Glasgow, Scotland (Jan 2000 to May 2007) was undertaken. Antiplatelet agents were stopped 5 days before biopsy in one centre but continued in the other. Bleeding time was not measured before biopsy and pro-coagulants were not routinely administered. Major bleeding was defined as the need for blood transfusion, surgical or radiological intervention. Minor bleeding was defined as an >or=1.0 g/dL fall in haemoglobin following biopsy without the need for transfusion or intervention.

RESULTS

Haemoglobin fell by >or=1.0 g/dL in 221 (19.7%) patients. There were 21 (1.9%) major bleeding complications. No patient died or required nephrectomy. Gender, advancing age or worse renal impairment was not associated with an increased likelihood of bleeding. Bleeding complications in 75 patients continuing antiplatelet agents were compared with those occurring in 60 patients whose antiplatelet agents were discontinued. Minor complications were commoner in the first group (31.0 versus 11.7%; P = 0.008), though there was no difference in the rate of major complications.

CONCLUSIONS

The risk of major bleeding following a native renal biopsy under ultrasound guidance is low. Stopping antiplatelet agents before biopsy was associated with a lower rate of minor complications but there was no difference in the rate of major complications. Complication rates compare favourably with other published series in which bleeding time was checked and corrected.

Risk management of renal biopsy: 1387 cases over 30 years in a single centre

BACKGROUND

Although renal biopsy is largely employed, even in old patients with systemic diseases, few clinical studies have addressed its risk management. We aimed to obtain a comprehensive assessment of safety/utility ratio of percutaneous renal biopsy.

PATIENTS AND METHODS

Retrospective review of all the 1387 patients who consecutively underwent renal biopsy in a single centre over three decades (1973-2002) was made, with calculation of complications, multivariate logistical analyses to evaluate risk factors of complications, and rate of alteration of clinical hypotheses by pathological diagnosis.

RESULTS

There were no deaths and five major complications, (0.36%). One nephrectomy (0.07%), two surgical revisions (0.1%) and two arterial-venous fistulae (0.1%). There were also 337 minor bleeding complications (24.2%) (16.4% gross haematuria and 7.8% clinically relevant haematomas needing at least prolonged bed rest). Multivariate analyses demonstrated that the risk for complications was significantly increased by systemic autoimmune diseases with odds ratio (OR) 2.06, 95% confidence interval (CI)=1.40-3.01, end-stage kidney/acute-tubular necrosis (OR 2.96, 95% CI=1.19-7.30), and prolonged bleeding time test (BTT) (OR 1.87, 95% CI=1.17-2.83). Among the 1288 cases in which a clinical hypothesis before renal biopsy was recorded, renal pathology changed previous diagnoses in 423/1,288 (32.8%) of cases.

CONCLUSIONS

Risk assessment demonstrates that renal biopsy is a useful procedure with a low incidence of serious complications. Platelet function is the only modifiable factor significantly related to bleeding complications, suggesting the need for a more standardized alternative to the BTT. Platelet function should be evaluated to select low-risk patients for renal biopsy as 'a day case procedure', in order to build adequate risk management strategies.

Renal biopsy: update

PURPOSE OF REVIEW

The renal biopsy is an invaluable tool in the diagnosis, prognosis, and management of patients with kidney disease. As the success of the procedure is defined not only by the ability to obtain adequate tissue but also by the safety profile, significant advances which define risk factors and determine the optimal timing of observation after the percutaneous native renal biopsy merit discussion. Alternative methods of obtaining tissue, such as transvenous renal biopsies, have also been described, especially in patients with contraindications to the percutaneous method.

RECENT FINDINGS

The percutaneous renal biopsy has been established as a safe and effective method of obtaining renal parenchyma. Complications, although rare, may occur and the majority of these are related to bleeding. The optimal timing of observation after the biopsy should be determined by when most complications occur, and, as over 33% of complications occur after 8 h, an observation period of at least 24 h is recommended. In patients with contraindications to the percutaneous approach, such as failure of adequate radiologic visualization or a bleeding diathesis, alternative methods of obtaining tissue have been attempted. These include open, laparascopic, transurethral, or transvenous renal biopsy.

SUMMARY

Without contraindications, the percutaneous renal biopsy remains the standard method of acquiring renal tissue. At least 24 h of observation is recommended after the percutaneous native kidney biopsy for the development of potential complications. When a contraindication to the procedure exists, other methods of renal biopsy by experienced physicians may be attempted.

Predictors of bleeding complications in percutaneous ultrasound-guided renal biopsy

BACKGROUND

The risks associated with performing a percutaneous renal biopsy have substantially decreased in the past two decades because of technical advances in the method. However, bleeding complications still occur, resulting in increased hospital stay and treatment costs.

METHODS

We investigated the predictive value of demographics (age, gender), clinical data (blood pressure), baseline chemistry (hemoglobin/hematocrit, prothrombin time, partial thromboplastin time, bleeding time, serum creatinine, daily proteinuria), and needle size for the risk of major (need for blood transfusion, nephrectomy, or angiography) or minor (no need for any intervention) postrenal biopsy bleeding complications. This was a prospective cohort study of 471 patients who underwent ultrasound-guided biopsy of native kidney by automated needle in a single center; all biopsies were performed by two experienced nephrologists. Patients with transplant kidneys were excluded from the study. Predictors of postbiopsy bleeding were assessed by multiple linear and multivariate logistic regression analysis. Data are presented as unadjusted (OR) and adjusted odds ratios (AOR) with 95% confidence intervals (CI).

RESULTS

The study cohort consisted of 471 (277 males, 194 females) patients. Of these, 161 (34.1%) experienced postbiopsy bleeding [157 (33.3%) hematomas, 2 (0.4%) gross hematuria, 2 (0.4%) arteriovenous fistula]. Major complications were seen in 6 (1.2%) patients (blood transfusion, N= 2; angiography, N= 3; nephrectomy, N= 1), but no deaths occurred. The risk of postbiopsy bleeding was higher in women (39.7% women, 30.3% men, AOR 2.05, 95% CI 1.26 to 3.31, P= 0.004), younger subjects (35.0 +/- 14.5 years vs. 40.3 + 15.4, AOR 0.80, CI 0.68 to 0.94, P= 0.006), and patients with higher baseline partial thromboplastin time (102.7 + 11.8% vs. 100.1 + 10.0%, AOR 1.26, CI 1.02 to 1.54, P= 0.032). These findings were independent of size of hematoma.

CONCLUSION

Although the methods for performing a percutaneous renal biopsy have improved in the past two decades, renal biopsy is still not a risk-free procedure. Of the data routinely collected for potential predictors of postbiopsy bleeding complications, only gender, age, and baseline partial thromboplastin time show a significant predictive value. The other variables investigated do not have any predictive value.

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.

Percutaneous renal biopsy

Percutaneous renal biopsy (PRB) is an integral part of the clinical practice of nephrology. It is essential in the diagnosis of glomerular, vascular, and tubulointerstitial diseases of the kidney, providing information that is invaluable in prognosis and patient management. The use of real-time ultrasound and automated biopsy needles has simplified and improved the success and safety of this procedure. In the recent past, we have seen a shift of the PRB from nephrologists to radiologists and this has raised appropriate concern that loss of this procedure may undermine the nephrologist's status as a subspecialist. We must continue to properly train young nephrologists in the proper technique and value of performing renal biopsy procedures or we stand to lose control of a procedure that was an integral part of the development of our subspecialty.

Discontinuation of the Bleeding Time Test without Detectable Adverse Clinical Impact

Background: The bleeding time (BT) test predicts a higher bleeding complication rate in populations at risk for inherited or acquired platelet dysfunction, but it is of limited assistance in evaluating individual patients. There are no reports of clinical outcomes after discontinuation of the BT test.

Methods: Interviews with a subset of the physicians who had ordered the BT test before discontinuation of the test were conducted. The total number of platelet-aggregation tests, the mean number of monthly, unmodified platelet units transfused, the incidence of kidney biopsy complications, and the number of doses of 1-deamino-8-d-arginine vasopressin (DDAVP) administered 5 months before and after discontinuation of the BT test were compared. We recorded the rates of bleeding complications in the Major Surgery Risk Pool during the 12 months before and the 5 months after the discontinuation of the BT test.

Results: Clinicians reported they did not significantly change their preprocedural work-ups, postpone an invasive procedure, experience an increase in bleeding complications, or increase their use of blood products after discontinuation of the BT test. Platelet-aggregation tests (n = 9, before and after), platelet transfusions (P = 0.958), and DDAVP administration (before = 24; after = 10) did not increase after discontinuation of the BT test. The rate of postprocedural bleeding complications did not increase significantly in either Major Surgery Risk Pool cases (&lt;3ς deviation from the mean rate) or in patients undergoing renal biopsies (P = 0.225 for decrease in hematocrit; P = 1.000 for the percentage of patients transfused) after discontinuation of the BT test.

Conclusions: Our study failed to identify a clinically significant, negative impact of discontinuing the BT test.

Platelet count may predict abnormal bleeding time among pregnant women with hypertension and preeclampsia

BACKGROUND

Anesthesiologists often require laboratory data to estimate the bleeding risk among hypertensive pregnant women prior to administering regional anesthesia. Many rely on the bleeding time (BT) in making this determination. We examined whether the platelet count can adequately predict BT among a group of hypertensive parturients.

METHODS

This retrospective subgroup analysis, taken from a cohort of 2,051 hypertensive pregnant women, comprises 87 individuals who underwent both a BT and platelet count prior to delivery. We calculated the correlation between the platelet count and BT at three platelet cut-off points with respect to prolonged BT of eight minutes or more.

RESULTS

There was a significant negative correlation between platelet count at delivery and BT [r= -0.45, 95% confidence interval (CI) -0.26 to -0.60; P <0.0001]. All three platelet cut-off points had a sensitivity of less than 66% with negative predictive values below 75% for an abnormal BT. A platelet count > or =75 x 109/L [corrected] was specific for the presence of an abnormal BT (specificity 97.8%, 95% CI 91.7-100.0), with a positive predictive value of 95.5% (95% CI 83.1-100.0) and a positive likelihood ratio of 24 (95% CI 3.3-168).

CONCLUSIONS

In a group of hypertensive parturients, the platelet count appears to be very specific for predicting a prolonged BT The platelet count may aid the anesthesiologist in determining the risk of bleeding from regional anesthesia. Given the study's potential for bias future research is needed to validate these findings.

Renal biopsy in high-risk patients with medical diseases of the kidney

The number of high-risk patients undergoing renal biopsy is likely to increase in the near future because of the increased use of anticoagulants for such conditions as atrial fibrillation, combined liver and kidney disease caused by hepatitis C, and the aging of the population. Nephrologists need to become increasingly familiar with evaluating such patients through both specialized management of percutaneous kidney biopsy and alternate methods of renal biopsy, which primarily consist of open (surgical) biopsy, transjugular (transvenous) biopsy, and laparoscopic biopsy. The indications, complications, and general approach to such patients are discussed. This is a US government work. There are no restrictions on its use.