MO122: Bleeding Complications after Allograft Kidney Biopsy and Role of Antiplatelet Therapy
Authors: Cazzato Silvia , Fontana Francesco , Giaroni Francesco , Bertolini Fabrizio 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Percutaneous biopsy is an important tool for monitoring renal allograft and early diagnosis when dysfunction occurs. Bleeding is the most dangerous adverse event, even if it is rare (risk of 0.5%). Cardiovascular (CV) disease affects 2/3 of elderly with CKD and antiplatelet therapy is taken for primary and secondary prevention of CV events. A systematic review on aspirin discontinuation among 50 279 patients at risk for coronary disease shows a 3-fold risk of adverse CV event. The aim of this study is to compare bleeding complications of antiplatelet administration within 5 days from renal biopsy versus absence of therapy.

METHOD
We conducted a 10-year (2010–2020) single-centre retrospective study on 285 consecutive ultrasound assisted percutaneous allograft kidney biopsy. We collected information about demographic, laboratory (eGFR, platelets, haemoglobin pre/post biopsy, proteinuria) data, biopsy indication (elective/urgent), clinical presentation [acute kidney injury (AKI)/nephrotic syndrome], needle gauge, use of antiplatelet or anticoagulant, diagnosis and complications (categorized as minor and major, according to the need for intervention). We divided patients in two groups: antiplatelet therapy within 5 days versus therapy discontinuation or absence. Bivariate logistic regression was used to analyse possible risk factors associated with complications.

RESULTS
Among the 285 patients: 173 patients received antiplatelet agents (low-dose aspirin in &gt;90% of cases) within 5 days from biopsy and 112 patients were not on antiplatelet therapy. Diastolic hypertension, AKI and proteinuria were statistically greater in the group without antiplatelet therapy. Histologic diagnoses were evenly present in the two groups, and no differences were observed in the rate of complications. Major complications were diagnosed in 0/112 patients without antiplatelet therapy and 1/173 patients with therapy within 5 days. Minor complications were documented in 14/112 and in 15/173 patients, respectively. There were no statistically significant differences in terms of complications between antiplatelet therapy within 5 days and absence of therapy (Table 1). Furthermore, there were no differences between taking antiplatelet within 48 h or stopping it within 48 h of the procedure (Table 2). No deaths were attributed to procedure and all events occurred within 24 h from biopsy, irrespective of their severity. The univariate logistic regression model (dependent variable: major complication) documented a lower BMI as a significant risk factor; indeed, this was not confirmed at multivariate regression. The analysis did not find a significant difference between 16-G and 18-G biopsy needle in terms of major/minor complications; however, the use of the latter was associated with a significant lower number of glomeruli in the sample.

CONCLUSION
Our study suggests that the use of antiplatelet agents within 5 days from procedure does not increase the bleeding risk, so it should be safe to continue the therapy in patients at risk for CV events. However, this is a weak evidence that needs prospective studies to be validated. Our data also suggest that 16-G biopsy needle may be safely used to obtain enough tissue for histologic diagnosis.