A NOVEL APPROACH TO GRAFT KIDNEY BIOPSY – ANALYSIS FROM A SINGLE CENTRE

Introduction:

Allograft kidney biopsy is cornerstone procedure in renal transplant patients. Biopsies are used to diagnose various pathologies that affect graft function. Historically, graft biopsies performed using perpendicular needle insertion, targeting renal cortex. This approach could result in inadequate sampling of glomeruli and arteries and could lead to higher complication rates due to deeper penetration and inadvertent vascular injury. Traditional biopsy techniques differ in their ability to obtain adequate samples and their associated complication rates. Important complications include bleeding, hematoma and rarely graft loss.

Patel et al. showed that the cortical tangential sampling (CTS) method for graft biopsy achieved a success rate of 95% and a complication rate of 2.1%. This study used the above-mentioned approach combined with gel foam plugging of the intrarenal track. Biopsy adequacy  and complications were analysed.

Methods:

This is a retrospective study which reviewed 100 allograft kidney biopsies performed on 71 patients (61 male and 10 female) at a single tertiary care center from January 2020. Graft biopsy was performed using an 18-gauge, 16 cm biopsy gun. A coaxial needle  was used to penetrate the graft capsule using a cortical tangential approach and biopsy performed by inserting the gun through the guide needle. The intragraft biopsy track was plugged with AbGelTM - a surgical sponge made into slurry with saline.  Adequacy was evaluated based on the Banff  97 criteria. Post-procedural complications were studied and recorded. One core was obtained in 36 samples, and two cores were obtained in 64 samples.

Results:

17.8 ± 8.81 (SD) glomeruli and 1.9 ± 0.4 arteries were obtained per biopsy. Number of glomeruli per pass on average was 11.06 ± 5.9. Number of arteries was not mentioned in 12 reports. Of the 8 cases with inadequate glomeruli, 3 were missing only one glomerulus to reach minimal adequacy. According to the Banff 97 criteria, 92% of samples contained at least minimally adequate glomeruli, and 98% of samples contained adequate arteries. All the inadequate biopsies were in patients in whom a single core was obtained. All the biopsies were performed by one nephrologist in association with three different radiologists. One patient had self-limiting gross haematuria without fall in haemoglobin and one patient had a immediate post procedure perinephric collection which stabilized with local pressure and observation.  The average haemoglobin (Hb) pre-biopsy and post-biopsy were 11.4 ± 2.2 g/dl and 11.3 ± 2.2 g/dl, respectively. No major complications like severe bleeding, requirement of transfusion, embolization of bleeder, graft nephrectomy was noted in the study population. 

Conclusions:

The results of this study showed the combined CTS and gel foam plugging technique offers a highly effective and safe method for allograft kidney biopsies. The high rate of adequate biopsies achieved in this study with 92% for glomeruli and 98% for arteries which is consistent with or superior to the rates reported in previous studies. Patel et al. (2010) demonstrated a 95 % success rate using the CTS method, while Quiroga et al (2001) reported a lower adequacy rate of 85.5% with the traditional methods. This method has demonstrated a high success rate for obtaining adequate tissue samples while maintaining  low complication rates. 

This abstract was also submitted at the AVATAR 2024 Congress. 

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.