MO160: Prolonged Closure Times in the Absence of Anti-Platelet Therapy and the Incidence of Haemorrhagic Complications After Native Kidney Biopsy
Authors: Avgustin Rotar Nusa , Rotar Ziga , Ales Rigler Andreja , Podgornik Helena , Lindič Jelka 
Published: May 2022

Abstract

BACKGROUND AND AIMS
The closure times [CTs; i.e. collagen/epinephrine (COL Epi) and collagen/adenosine 5-diphosphate (COL ADP)] are frequently used to evaluate primary haemostasis before kidney biopsy, although their usefulness to predict hemorrhagic events remains elusive [1]. CTs can be prolonged not only by antiplatelet agents but also by e.g. the presence of anaemia, thrombocytopaenia, uremic conditions in patients with advanced stages of chronic kidney disease (CKD) and even the circadian rhythm among others, which limits their dependability/usefulness [2–4]. We aimed to investigate the assumed association between prolonged CTs and the occurrence of hemorrhagic complications after kidney biopsy [5] in patients with CKD and to explore possible factors influencing their values.

METHOD
We retrospectively analysed following data collected during medically indicated ultrasound (US)-guided kidney biopsies in patients without antiplatelet/anticoagulant therapy or after its discontinuation for at least 1 week before the procedure: demographic and clinical data, kidney size and resistance index (RI) measured by ultrasound (US) on the biopsied kidney, serum creatinine (μmol/L), estimated glomerular filtration rate (eGFR; mL/min/1.73 m2; using CKD-EPI equation), basic haemostasis tests [prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT)] and CTs (COL Epi and COL ADP; seconds) to assess platelet function. We also collected data on haemoglobin concentration (g/L) and platelet counts (109/L) before and no longer than 24 h after the biopsy, the development of haematoma (HMT) up to 24 h after the procedure, macrohematuria, need for transfusion, percutaneous or surgical intervention. The analysis was performed with the statistical program R, using Student's t test, Mann–Whitney test and Fisher's exact test for categorical variables. P values &lt; .05 were considered significant.

RESULTS
In 2016, our centre performed 144 biopsies of native kidneys, 141 kidney biopsies were included in the analysis. None of the patients had post-procedural macrohematuria or HMT requiring percutaneous or surgical intervention. None of the patients required a transfusion. Independently of CTs, haemoglobin decreased by ≥10 g/L in 25 (18%) patients. HMT was described in 39 (28%) patients. A total of 27 (20%) patients had to discontinue antiplatelet therapy (APT) prior to biopsy. There was no statistically significant difference in HMT occurrence in comparison to patients without APT (P = .346). Patients with APT had higher renal RI (0.77 versus 0.72, P = .049) and even after discontinuation of APT prolonged COL ADP (115 versus 97, P = .02), compared to patients without APT. Differences in PT/INR and aPTT values between groups were insignificant. Table 1 compares patients with prolonged and normal CTs. COL Epi was above the normal range in 20 (16%), COL ADP in 25 (20%) and either or both in 31 (25%) patients, respectively. Blood haemoglobin before biopsy trends to be slightly lower in patients with prolonged CTs (P = .066).

CONCLUSION
In our cohort of patients without or after timely discontinued APT, there were no serious adverse outcomes of kidney biopsy whether the CTs were prolonged or not. The persistently prolonged CT is nevertheless an important information that should not be omitted, especially in combination with other patient characteristics (e.g. anaemia, depth of the kidneys, blood pressure immediately before the procedure, etc.), that are influencing the individual biopsy provider's choice of needle gauge, the number of punctures that provide the additional safety of invasive procedure and its complications.