Transplant Liver Biopsies: Does Biopsy Needle Gauge Matter?

A transplanted liver often require random liver biopsies to evaluate for rejection and other possible etiologies of elevated liver function tests. The choice of biopsy needle size (18G vs. 20G) is operator dependent. In this study, we reviewed transplant liver biopsies over a 4-year period to assess sample adequacy as determined by pathology and complication rate for 18G vs. 20G spring loaded two stage deployment biopsy needles.

Materials and Methods: An IRB-approved retrospective study of 397 random transplant liver biopsies performed between January 2020 and August 2024 utilizing 17G/18G or 19G/20G coaxial and core two stage spring loaded needles was performed.   There were 233 male and 163 female patients with a mean age of 52 years (+/- 15.6). Patient medical records were reviewed for needle size, number of cores/passes performed, tract embolization agent used, complication rate (bleeding/infection), and sample adequacy deemed by pathology. Statistical significance was determined using a combination of t-tests and chi-squared tests with a significance level designated as less than 0.05. 

Results:

There were 257 18G core biopsies and 140 20G biopsies. Sample inadequacy was noted in 3/257 of the 18G biopsies and 19/140 of the 20G biopsies (p < 0.0001). The mean number of cores taken was 3.17 +/- 0.72 and 3.06 +/- 0.81 for 18G and 20G biopsies, respectively (p = 0.14). Additionally, there was no difference between the 18G and 20G groups regarding the number of cores taken in the adequate or inadequate samples. Tract embolization was performed in 352/397 biopsies. Gel foam slurry was used in 329 cases, autologous blood clot was used in 20 cases, gelfoam pledglets were used in two cases, and thrombin was used in one case. Twenty cases had no tract embolization performed. Only one clinically significant bleeding complication was noted in a procedure done with a 20G needle in which two core biopsies were performed. The patient underwent angiography and embolization of the bleeding vessel with gelfoam slurry with stabilization. No other major complications were noted. 

Conclusion:

Random transplant liver biopsies performed with 17G/18G spring loaded two stage deployment coaxial and core biopsy needles with three core samples are more likely to provide adequate samples than three core samples from 19G/20G biopsy needles. The risk of complications in transplant liver biopsies is low. Tract embolization may lower the risk of complications, but further comparison studies with larger sample sizes are needed.