Renal Allograft Thrombosis
Vinayak S. Rohan
John W. McGillicuddy
Kenneth D. Chavin
DEFINITION
Renal allograft thrombosis occurs in the renal artery and/or the renal vein after renal transplantation. Thrombosis is responsible for 2%1 of graft loss in adult recipients. Salvage efforts are appropriate in most cases, but renal allograft thrombosis is a devastating complication that most often leads to graft loss.
PATIENT HISTORY AND PHYSICAL FINDINGS
The etiology of renal allograft thrombosis is usually multifactorial. Technical errors, blood stasis, endothelial injury, and thrombophilia all cause renal allograft thrombosis. Technical factors include poorly constructed anastomoses, unrecognized intimal flaps, malposition of the graft, graft rotation, and external compression. These most commonly cause early (<14 days) graft thrombosis. Thrombophilia is more likely to cause late (>14 days) thrombosis.2,3 A detailed list of risk factors for renal allograft thrombosis is noted in Table 1.
Arterial thrombosis of the graft must be considered when an absence of graft function is not otherwise explained. Remember that anuria of the graft may be obscured by native renal function. Anuria, whether it develops immediately or in the early postoperative period, should be evaluated promptly. Depending on the circumstances and index of suspicion for a vascular complication, evaluation should include emergent return to the operating room or a duplex ultrasound.
Renal vein thrombosis shortly after renal transplantation is usually associated with a technical problem. The clinical presentation of graft vein thrombosis is oliguria and occasionally hematuria. The patient may complain of pain over the graft site, and on exam, tenderness over the graft is common. Duplex ultrasound is useful in establishing the diagnosis.
DIFFERENTIAL DIAGNOSIS
Because vascular thrombosis needs immediate therapy, it is the diagnosis of exclusion for oliguria and anuria following kidney transplantation. Additional etiologies of oliguria and anuria include delayed graft function, hypovolemia, urinary complications, and graft rejection.
Table 1: Risk Factors for Renal Allograft Thrombosis | ||||||||||||||||||||
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IMAGING AND OTHER DIAGNOSTIC STUDIES
In the event that urgent radiologic investigation is warranted, duplex ultrasonography is the most expeditious choice.
Renal artery thrombosis is diagnosed when duplex and color Doppler fail to demonstrate intrarenal venous and arterial flow.
Renal vein thrombosis is associated with an absence of demonstrable flow in the extrarenal vein and an arterial waveform that demonstrates reversed, plateauing diastolic flow (FIG 1). Although reversal of flow in diastole can be seen in other conditions, when it is associated with an absence of flow in the renal vein, the diagnosis is clear.4Related posts:
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