This study compared the effectiveness and safety of traditional "blind" renal allograft biopsies versus real-time ultrasound guided coaxial biopsies. A retrospective review of over 800 biopsies in over 600 patients found that while both techniques obtained a diagnostic sample in over 99% of cases, the traditional technique resulted in significantly more minor complications such as hematomas and arteriovenous fistulas. However, the rates of major complications requiring intervention were not significantly different between the two groups. In conclusion, real-time ultrasound guided coaxial biopsies may reduce the risk of minor complications without increasing the risk of major complications compared to traditional blind biopsies.

1. Xin Ye MD, Ana Maria Gomez MD, Steven Raman MD, David Lu MD, Justin
McWilliams MD
University of California, Los Angeles
David Geffen School of Medicine
Department of Radiology

2.  Renal transplant survival is threatened by1:
◦ Rejection
◦ Acute tubular necrosis
◦ Infection
◦ Drug toxicity
 Imaging cannot differentiate between medical complications.

3.  The diagnostic gold standard2-3.
 Risk of bleeding causing hematoma and hematuria.
 Goal of biopsy: target avascular renal parenchyma in lower
pole cortex and avoid hilar structures and vessels.
 2 biopsy techniques are used at UCLA.

4.  Position and depth marked beforehand by US.
 18 gauge core biopsy device is then advanced without real-
time guidance.
 On site pathology tech assesses adequacy.
 Re-biopsy requires repeated punctures through the renal
capsule.

5.  Performed under real time US guidance.
 17 gauge coaxial introducer is advanced
through the renal capsule.
 18 gauge core biopsy device is passed
through the introducer.
 No re-puncturing of the renal capsule
with re-sampling.
 Gelfoam embolization for hemostasis.
Coaxial introducer advanced under
US guidance1

6.  Exclusion criteria:
◦ Severe anemia, platelets < 50,000 and prolonged PT with INR greater
than 1.5
 BP < 160/90 mm Hg.
 Diagnostic US
◦ Position, echotexture, renal vasculature, exclude hydronephrosis and
perinephric fluid
 Nephrology typically refers more technically difficult patients
to IR.

7.  We compared the effectiveness and complications of two
institutional renal biopsy techniques: the traditional “blind”
technique versus a real time ultrasound (US) guided coaxial
technique.

8.  Retrospectively analyzed 608 patients who underwent 866 renal
allograft biopsies between 7/28/2008 and 12/06/2010.
 Diagnostic quality of biopsy samples was assessed by review of
pathology reports.
 Complications were determined from post-biopsy US reports and
from review of patient notes for 2 weeks following biopsy.
 Minor complications: asymptomatic hematomas and
arteriovenous fistulas (AVF’s), and minor hematuria.
 Major complications: complications requiring medical or surgical
intervention.

9. Fig 1. Perinephric hematoma. Fig 2. Arteriovenous fistula.

10. Traditional Coaxial
Number of patients 415 193
Number of biopsies 625 241
Mean age 33 +/- 20 53 +/- 13
Male 253 (61%) 119 (62%)
Female 162 (39%) 74 (38%)

11. Traditional Coaxial
Insufficient samples 6 (0.96%) 1 (0.41%) p = 0.68
Minor complications 41 (6%) 5 (2.1%) p = 0.01
Hematoma, asymptomatic 25 2
AVF, asymptomatic 14 2
Hematuria, self limited 2 1
Major complications 3 (0.5%) 2 (0.8%) p = 0.62

12. Traditional AVF leading to gross hematuria, bladder hematoma, and mild hydronephrosis.
Resolved with IVF and bladder irrigation.
Gross hematuria with a drop in Hg and urinary obstruction 2/2 bladder hematoma.
Stabilized after IVF, foley, and pRBC transfusion.
Large extracapsular hematoma after biopsy causing LLQ pain and renal compression
that required surgical decompression.
Coaxial Pt h/o MVR was restarted on heparin 12 hrs post-biopsy, became coagulopathic with
PTT > 140. Developed a large subcapsular hematoma that lead to renal compression
and renal failure. Required surgical decompression, dialysis, and transfusion.
Hematoma, bleed at biopsy site, and drop in Hg after heparin was restarted 24 hr
post op. Stabilized after heparin was held and IVF, pRBC transfusion were given.

13.  No significant difference in rates of acquiring diagnostic
samples.
 Both techniques demonstrate acceptably low risk of major
complications without a significant difference.
 Traditional technique showed significantly higher rate of
minor complications, which may or may not be of clinical
significance.

14. 1. Real Time Ultrasound Guided Coaxial Renal Transplant Biopsy with Gelfoam Injection for Hemostasis:
Single Center Experience. Gomez AM, Raman SS, Anaya CA, Lu DS. Manuscript.
2. Racusen L.C, Solez K, Colvin R.B, Bonsib S.M et al. The Banff 97 working classification of renal allograft
pathology. Kidney International 1999; 55:713-723.
3. JG Letourneau, DL Day, NL Ascher, WR Castaneda-Zuniga. Imaging of renal transplants. Am. J. Roentgenol
1988; 150:833-838.