Introduction:
Renal biopsies are done all over the world by nephrologists and radiologists for myriads of indications on a daily basis. They are unfortunately associated with several dreaded complications, the worst of which is the post -biopsy bleed. The incidence of bleeding post biopsy has been reported to be between 0-6% in various studies. What is the current rate of bleed with the use of automated guns? Does the technique of pre-marked biopsy vs real time kidney biopsy affect the risk of bleeds? Does the number of samples determine the rate of bleed? These are some of the questions this study aims to address.
Methods:
A prospective cohort study of all patients undergoing biopsy over the period of a 1 year was conducted where all patients who were undergoing a renal biopsy were serially recruited after informed consent. The risk factors for bleed, co-morbidities, BMI, age, techniques used, number of samples, number of attempts, depth, other radiologic and histopathological aspects were noted. The rate of bleed was identified and in patient who bled additional findings such as methods used to stop the bleed, additional incurred cost and duration of hospitalization were noted.
Results:
An Interim analysis was done on 682 patients who underwent renal biopsy at a single center between the time period of June 2023-June 2024. 92% of patients underwent renal biopsy using the pre-marked technique of biopsy. The rate of bleed was 5.1/100 biopsies. Among these only 1.6% were clinically significant requiring any intervention including transfusion. Only 0.7% of patients required embolization. There was no fatality due to the biopsy in this data. The clinical and laboratory risk factors associated with bleeding were creatinine, urea and requirement of dialysis (p value<0.05). Both diabetes and ischemic heart disease were associated with trend to significant bleed. The grade of corticomedullary differentiation was significantly associated with risk of bleed however the depth, lower pole cortical thickness or size of the kidney were not associated significantly with risk of bleed. The number of passes and samples were not significantly associated with bleeding risk. The only histopathological variable associated with risk of bleed was the number of vessels on the renal biopsy. The number of glomeruli, degree of IFTA and the degree of atherosclerosis were not associated with risk of biopsy bleed. The average duration of stay incurred due to the bleed was 2.78 days (2SD: 3.10) and the additional cost incurred was a median of Rs5027 (IQR: 842-20,058). The most common intervention for the bleed was only monitoring.
Conclusions:
The rate of bleed is low and in keeping with data around the world. It is comparable with data from other centers where renal biopsies are performed real time. The cortico-medullary differentiation on the kidney ultrasound was identified as an important radiologic risk factor for bleed. The most clinically significant risk factor was the degree of creatinine elevation rather than the bleeding parameters. Number of vessels on the biopsy rather than degree of atherosclerosis, glomerulosclerosis or interstitial fibrosis and tubular atrophy was significantly correlated with risk of bleed. This article highlights novel risk factors for bleed using the pre-marked technique of doing a kidney biopsy.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.