RENAL TRANSPLANT

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RENAL TRANSPLANT
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History

• First successful transplant 1954
• 2 year survival rate is gt90 at present

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Eligible Patients

• Patient must have evidence of endstage renal
  failure, defined as current or impending dialysis
  dependency.
• Indications
• Glomerulonephritis (55)
• Diabetic nephropathy (20-30)
• Chronic pyelonephritis (8)
• Polycystic kidney disease (5)

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Contraindications

• Systemic malignancy
• Active infection
• Seropositivity, i.e., HIV, Hepatitis B
• Noncompliant patient

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Renal Allograft

• Allograft Any tissue transplanted from one
  human to another.
• Renal allograft harvested
• From living, related donor
• From brain dead donor (cadaveric)

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Surgical Technique

• Surgical implantation into right or left iliac
  fossa, most often on the right.
• Generally, donor kidney is flipped
  anteroposteriorly before being placed in the
  iliac fossa to facilitate the vascular
  anastomosis and ensure correct orientation of the
  ureter.

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Vascular Hookup

• Due to its lower incidence of renal artery
  stenosis, an end renal artery to side
  external iliac artery anastomosis is preferred
  over end renal artery to end internal iliac
  artery.
• End to side anastomosis between the renal
  vein and the external iliac vein.

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A end-to-side anastomosis, allograft artery to
external iliac artery B end-to-end
anastomosis, allograft artery to internal iliac
artery C Carrells patch from the donor
aorta. Utilized for multiple renal arteries or
for a small renal artery from a child.
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Technical Considerations

• Superficial
• Anatomic detail is clearer
• Cortex may appear more echogenic
• Enlarges
• Adults, volume typically increases up to 30
• May increase up to 200 with discrepancy of donor
  to recipient size
• Dilatation of collecting system
• Slight hydronephrosis is common

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Rejection

• Sonographic Manifestations
• Increased allograft size
• Increased cortical echogenicity
• Increased prominence of renal pyramids
• Focal cortical hypoechoic regions
• Decreased echogenicity of renal sinus
• Increased flow resistance in parenchymal arteries

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Rejection
Acute
Chronic
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Increased Flow Resistance

• Zwiebel, Pg. 469
• RI 0.7
• Renal Transplant Imaging and Intervention
• RI gt0.9

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Perigraft Fluid Collections

• Seroma Hematoma
• Abscess
• Urinoma
• Lymphocele
• Zwiebel, pg. 471 Table 30-3

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Lymphocele
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Vascular Complications

• Arterial Stenosis
• Most common vascular complication, 10 of
  transplant patients
• Early most often a technical defect
• Later generally due to intimal hyperplasia
• Vascular Occlusion typically immediate, lt1 week
• Renal artery
• lt1 of all renal transplants
• Typically appears acutely
• Technical defect
• Rejection
• Renal vein
• lt1 of transplant patients

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Diagnostic Criteria

• Normal Flow Parameters
• Velocity 80 118 cm/s
• Volume flow 346 422 cc/minute
• Abnormal Flow Parameters stenosis gt5060
• Velocity gt190 cm/s with poststenotic turbulence
• Velocity 250 cm/s
• Systolic velocity ratio gt3

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Renal Artery Stenosis
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Renal Artery Stenosis
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Renal Vein ThrombosisDoppler Flow Characteristic
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Vascular Complications

• Arteriovenous Fistula
• Generally due to trauma from renal biopsy
• Pseudoaneurysm
• Generally due to trauma from renal biopsy
• May be at arterial or venous anastomosis

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A-V Fistula
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Pseudoaneurysm
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Pseudoaneurysm
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Sources

• Introduction to Vascular Ultrasonography, 4th
  Ed., Zwiebel, Chapter 30
• Renal Transplant Imaging and Intervention,
  Zwirewich
• www.radiology.co.uk/srs - x/tutors/renaltx/re
  n1.htm