Diagnostic Ultrasound - Abdomen and Pelvis

Transplant Renal Vein Thrombosis
TERMINOLOGY
Abbreviations
• Transplant renal vein thrombosis (TRVT)
Definitions
• Occlusion of transplant renal vein due to thrombus
formation
IMAGING
General Features
• Best diagnostic clue
○ Absence of blood flow in renal vein
○ Abnormal renal artery waveform with reversal of
diastolic flow
• Location
○ Entire vessel
○ Segmental thrombus (rarely caught early)
Ultrasonographic Findings
• Grayscale ultrasound
○ Enlarged, edematous, hypoechoic kidney due to outflow
obstruction
○ Renal vein distended by low echogenicity thrombus
○ Renal rupture with hemorrhage if late
• Color Doppler
○ Absence or decreased color flow in renal vein at hilum
– Patent renal artery early, later the renal artery will
thrombose also
– Absent to severely diminished parenchymal color
flow
• Spectral Doppler
○ Absent venous waveforms at renal hilum and in
parenchyma
○ High systolic arterial peaks with flow reversal in diastole
Imaging Recommendations
• Best imaging tool
○ Color, power, spectral Doppler US is first-line imaging
modality for complications of renal transplantation
• Protocol advice
○ Optimize color and spectral Doppler settings for slow
flow
DIFFERENTIAL DIAGNOSIS
Acute, Severe Rejection or Delayed Graft Function
• Vascular resistance in renal parenchyma markedly increased
○ Diminished, absent, or reversed arterial flow in kidney
hilum/intrarenal arteries
○ Renal vein is patent
Iliac Vein Thrombosis or Venous Compression
• Thrombus in ipsilateral iliac or femoral vein
• Extrinsic compression by fluid collection or hematoma
PATHOLOGY
General Features
• Etiology
○ Surgical injury or technical problem
– Kinking, angulation, or trauma to vein
○ Compression by fluid collection (e.g., hematoma,
lymphocele): Less common
– May result in compartment syndrome
○ Hypovolemia, hypercoagulable state
○ Thrombus propagation from common femoral/external
iliac vein
○ Rejection
• Associated abnormalities
○ Marked graft congestion/edema
○ Adjacent fluid collections
Gross Pathologic & Surgical Features
• Large vein thrombus extending into smaller veins
Microscopic Features
• Hemorrhagic necrosis
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Abrupt onset of graft tenderness and swelling,
decreased function
– Hematuria,oliguria, proteinuria
○ Usually within 1st week, most commonly within 48 hours
of transplantation
Demographics
• Epidemiology
○ ≤ 4% of transplants
Natural History & Prognosis
• Poor prognosis even with prompt diagnosis and
thrombectomy/surgical revision
• May progress to rupture with hemorrhage and
hypovolemia
Treatment
• Thrombectomy, surgical revision
DIAGNOSTIC CHECKLIST
Consider
• Renal vein thrombosis when there is a sudden drop in urine
output in early postoperative period
Image Interpretation Pearls
• Reversal of arterial diastolic flow and absence of venous
flow confirms this diagnosis
• Additional imaging causes needless delay
SELECTED REFERENCES
1. Rodgers SK et al: Ultrasonographic evaluation of the renal transplant. Radiol
Clin North Am. 52(6):1307-24, 2014
2. Low G et al: Imaging of vascular complications and their consequences
following transplantation in the abdomen. Radiographics. 33(3):633-52,
2013
3. Eufrásio P et al: Surgical complications in 2000 renal transplants. Transplant
Proc. 43(1):142-4, 2011
4. Kobayashi K et al: Interventional radiologic management of renal transplant
dysfunction: indications, limitations, and technical considerations.
Radiographics. 27(4):1109-30, 2007
Diagnoses: Kidney Transplant
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