Abnormal coagulation tests before kidney biopsies-what next?

A Rare Cause of Isolated Prolonged Activated Partial Thromboplastin Time: An Overview of Prekallikrein Deficiency and the Contact System

Prekallikrein (PK) deficiency, also known as Fletcher factor deficiency, is a very rare disorder inherited as an autosomal recessive trait. It is usually identified incidentally in asymptomatic patients with a prolonged activated partial thromboplastin time (aPTT). In this article, we present the case of a 52-year-old woman, with no prior personal or family history of thrombotic or hemorrhagic disorders, who was noted to have substantial protracted aPTT through the routine coagulation assessment before a kidney biopsy. The patient had an uneventful biopsy course after receiving fresh frozen plasma (FFP). Laboratory investigations performed before the biopsy indicated normal activity for factors VIII, IX, XI, XII, and von Willebrand factor (vWF) as well as negative lupus anticoagulant (LA) screen. The plasma PK assay revealed low activity at 15% consistent with mild PK deficiency. The deficit of PK is characterized by a severely prolonged aPTT and normal prothrombin time (PT) in the absence of bleeding tendency. PK plays a role in the contact-activated coagulation pathway and the inflammatory response. Thus, other differential diagnoses of isolated prolonged aPTT include intrinsic pathway factor deficiencies and nonspecific inhibitors such as LA. We concluded that the initial evaluation of a prolonged aPTT with normal PT should appraise the measurement of contact activation factors and factor inhibitors. PK deficiency should be considered in asymptomatic patients with isolated aPTT prolongation, which corrects on incubation, with normal levels of the contact activation factors and factor inhibitors.

Desmopressin and bleeding risk after percutaneous kidney biopsy

Background

Desmopressin is used to reduce bleeding after kidney biopsy but evidence supporting its use is weak, especially in patients with elevated creatinine. The present study was undertaken to evaluate efficacy of desmopressin in reducing bleeding after percutaneous kidney biopsy.

Methods

Retrospective cohort study. 269 of 322 patients undergoing percutaneous kidney biopsy between January 1, 2014 and January 31, 2018 were included. Patients had normal bleeding time, platelet count and coagulation profile. Primary outcome was defined as composite of hemoglobin drop ≥1 g/dL, hematoma on post biopsy ultrasound, gross hematuria, erythrocyte transfusion or angiography to stop bleeding. Association of desmopressin with outcomes was assessed using linear (for continuous variables) and logistic (for binary variables) regression models. Propensity score was used to minimize potential confounding.

Results

Desmopressin was administered to 100/269 (37.17%) patients. After propensity score adjustment patients who received desmopressin had increased odds of post biopsy bleeding [OR 3.88 (1.95–7.74), p < 0.001]. Creatinine at time of biopsy influenced bleeding risk; gender, emergent vs elective biopsy, obesity, AKI, diabetes, hypertension or bleeding time did not influence bleeding risk. Administration of desmopressin to patients with serum creatinine ≥1.8 mg/dL decreased bleeding risk [OR 2.11 (95% CI 0.87–5.11), p = 0.09] but increased bleeding risk when serum creatinine was < 1.8 mg/dL (OR 9.72 (95% CI 2.95–31.96), p < 0.001).

Conclusion

Desmopressin should not be used routinely prior to percutaneous kidney biopsy in patients at low risk for bleeding but should be reserved for patients who are at high risk for bleeding.

Comparison of Local Injection of Fresh Frozen Plasma to Traditional Methods of Hemostasis in Minimally Invasive Procedures

RATIONALE AND OBJECTIVES

To evaluate different techniques for reducing hemorrhagic complications in coagulopathic patients with elevated international normalized ratio having an image-guided percutaneous invasive procedure; techniques included systemic transfusion of fresh frozen plasma (FFP), local injection of FFP, percutaneous injection of gelatin sponge, and percutaneous placements of angiographic coils.

MATERIALS AND METHODS

Retrospective review of 232 consecutive patients with known coagulopathy undergoing image-guided minimally invasive procedures were selected. Ninety-one patients had local FFP injected, 40 patients underwent local synthetic gelatin injection, 16 patients had percutaneous coil embolization, and 85 patients received systemic FFP. The number of bleeds, complications related to bleeds, and systemic complications were recorded. A 30 cc threshold was used to delineate significant bleeding.

RESULTS

No patients experienced clinically significant or insignificant bleeding with local FFP injection (P value <.05). Other local hemostatic methods (Gelfoam, systemic FFP, and coil embolization) were associated with higher levels of bleeding (12.5%, 17.1%, 37.5%, respectively) and complications (7.5%, 31.4%, 37.5%, respectively). Systemic FFP infusion was associated with respiratory, infectious, and mortal complications.

CONCLUSIONS

Local injection of blood products provides a safe and efficacious hemostatic agent to reduce the incidence of postprocedural bleeding. The technique is associated with lower rates of bleeding and systemic complications when compared to other local and systemic techniques. Further randomized prospective studies with a larger patient cohort need to be performed to corroborate these initial findings.

Direct Injection of Blood Products Versus Gelatin Sponge as a Technique for Local Hemostasis

PURPOSE

To provide a method of reducing risk of minimally invasive procedures on patients with abnormal hemostasis and evaluate efficacy of direct fresh frozen plasma injection through a procedure needle tract compared to Gelfoam (gelatin sponge) administration.

MATERIALS AND METHODS

Eighty patients with elevated international standardized ratio (INR) undergoing minimally invasive procedures using imaging guidance were selected retrospectively. Forty patients had received Gelfoam as a means of tract embolization during the procedure. The other 40 received local fresh frozen plasma (FFP) through the needle tract. The number of complications and clinically significant bleeding events were recorded. A threshold of 30 cc of blood loss after a procedure was used to identify excess bleeding.

RESULTS

No patients experienced clinically significant bleeding after administration of FFP. Five patients experienced postoperative drops in hemoglobin or hematomas after administration of Gelfoam.

CONCLUSION

Local injection of blood products can reduce postprocedure bleeding in patients undergoing minimally invasive procedures and provides a safe alternative to the use of synthetic fibrin plugs.

Desmopressin use prior to renal transplant biopsy-does it fit?

Desmopressin acetate (DDAVP), a selective agonist of type 2 vasopressin receptors, is sometimes used prior to percutaneous renal biopsy to reduce the risk of bleeding complications. DDAVP increases free water reabsorption in renal collecting ducts, potentially leading to water intoxication or dilutional hyponatraemia. We present two cases, where DDAVP was used prior to percutaneous renal transplant biopsy and was associated with severe hyponatraemia and neurological sequelae. With DDAVP being advocated in many centres prior to percutaneous renal biopsy, these cases highlight the need for increased awareness regarding side effects. In this report, we provide suggestions on strategies to minimize hyponatraemia in this context.