Renal transplant biopsy specimen adequacy in a paediatric population

Abstract

Updated guidelines on the diagnosis of acute allograft rejection including criteria for biopsy specimen adequacy were published in 1999. We sought to determine the adequacy of specimens in paediatric transplant patients and identify factors influencing adequacy. All renal transplant biopsies performed between 1998 and 2003 were classified as adequate (n =25), minimal (n =19) or inadequate (n =27) in accordance with the Banff 97 criteria, and the histological diagnoses were documented. The effect on specimen adequacy of grade of operator, method of sedation, age of child, needle gauge, number of cores and total core length was then investigated. Overall, a minimal or adequate specimen was obtained in 62% of cases. No histological diagnosis could be made in 30% of all specimens, just over half of which were inadequate. Higher rates of rejection were found in adequate (52%) than inadequate (33%) samples. The grade of operator (p =0.498), the age of the child at the time of biopsy (p =0.815) and type of sedation (p =0.188) did not affect adequacy. More than one core was obtained in 38 (54%) cases, and this was significantly associated with specimen adequacy (p <0.0005) as was longer total core length (p =0.002). Clinical features in isolation are not sufficient for the diagnosis of acute allograft rejection. Renal biopsy remains the gold standard and relies on adequate specimen collection. Our data shows that specimen adequacy according to the Banff 97 guidelines is achievable in children and that more than one core at the time of sampling significantly improves this achievement. Adequate sampling reduces the risk of an inconclusive histological diagnosis.

Complications of Ultrasound-Guided Renal Transplant Biopsies

“…This single-center cohort is the largest known to be published (>2500 patients), and we demonstrated a similar rate of major complications compared with prior published reports (0-4%) (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Several very clinically important conclusions were drawn relating to renal transplant biopsy complications.…”

“…Minor complications occur in up to 17%, most commonly hematuria, arteriovenous fistula (AVF) and/or small hematoma (9,10). Major complications are usually described as those that require additional treatment, such as transfusion of blood products, surgical or vascular intervention, or prolonged hospitalization, and that are less frequent (0-4% in various cohorts) but can result in significant morbidity (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Risk factors for major complications are largely unknown because of their infrequent occurrence and the lack of investigational studies.…”

Renal Biopsy in the Pediatric Patient

“…As such, Birk et al (Birk et al, 2007) hypothesized that the slightly higher incidence of post-biopsy gross hematuria (8.4%) in their cohort of 43 renal transplant recipients compared to previously published reports (1.9-3.5%) was their use of a larger 16-G needle compared to an 18-G needle used elsewhere. With regards to other factors, several retrospective analyses have shown no significant difference in complication rates whether the biopsy was performed as an outpatient or inpatient procedure (Hussain et al, 2003(Hussain et al, , 2010Simckes et al, 2000), under general anesthesia or sedation (Durkan et al, 2006;Hussain et al, 2010;Webb et al, 1994), by a supervised trainee or by an attending physician or consultant (Durkan et al, 2006;Simckes et al, 2000), and between an intraperitoneal and extraperitoneal graft in the case of allograft percutaneous biopsies (Vidhun et al, 2003). Interestingly, in native percutaneous biopsies, one author (Hussain et al, 2003) observed a trend for a higher incidence of gross hematuria post biopsy in those patients with a histological diagnosis of IgA Nephropathy/ Henoch-Schonlein Purpura.…”

“…In the case of renal allografts, biopsies for urgent issues were noted to have a higher incidence of post biopsy hematoma compared to protocol biopsies (Vidhun et al, 2003). Increased number of passes was significantly associated with obtaining more adequate tissue for making a histological diagnosis (Durkan et al, 2006), but with a slightly increased but not significant trend towards hematoma formation (Simckes et al, 2000). Through the decades, the safety of percutaneous renal biopsy has been verified in several large pediatric case series.…”

Renal Pathology in the Pediatric Transplant Patient

“…In children, obtaining more than 1 core of the allograft or increasing the total core length to 2 cm improves the likelihood of an adequate specimen. 6 Renal allograft biopsies are generally divided for light (LM), immunofluorescence (IF), and electron microscopy (EM) with most of the sample used for LM. A dissecting microscope at the bedside is very useful for determining, at the time of biopsy, if the specimen has glomeruli and for dividing it for LM, IF, and EM (Fig.…”