Traumatic renal artery dissection

Clinical History

A 42 year old patient was referred to our institute after a major thoracic trauma.

Imaging Findings

A 42 year old patient reported a major thoracic trauma while he was working with a farm tractor. He was immediately referred to our institute to perform an abdominal spiral CT angiography because of a state of shock, and it revealed the presence of liver and pancreas contusions with a peri-hepatic effusion, and a marked and diffused right kidney hypoperfusion (Fig. 1a,b) because of right renal artery focal dissection (Fig. 1c). He immediately underwent abdominal and right kidney aortography which confirmed the acute obstruction of the right renal artery without re-canalization (Fig. 2a).
In attempt to correct the defect with the right renal artery selective catheterism, a micro guide was successfully advanced through the true lumen of the renal artery, distally to the dissection. After systemic heparinisation, a direct stenting was performed in the true lumen, obtaining an endoluminal remodelling (Fig. 2b). Thrombo-embolic material mobilization in renal parenchyma was subsequent to the procedure and urokinase was administered to the patient to solve it. The final angiography showed the reperfusion of 60% of the right kidney parenchyma (Fig. 2c). A spiral CT angiography was performed 7 days later and it showed the stent patency (Fig. 3a) with partial reperfusion of the right kidney and only small infarcted subcortical areas (Fig. 3b,c).

Discussion

Renal vascular injury is reported in 1-4% of blunt abdominal trauma cases.
Included in this category are stretch injuries to the vascular pedicle, which may result in renal artery avulsion or intimal tear with dissection and stenosis. In particular, intimal tears in the renal arteries typically result from traumatic mechanisms that produce rapid deceleration. When the tear leads to dissection with luminal stenosis, early diagnosis and repair will preserve parenchymal function. The latter is typically asymptomatic and only diagnosed after the vessel has thrombosed. These lesions are usually accompanied by surrounding perirenal haematomas and associated visceral trauma that often precludes surgical revascularization.
However, a patent artery with a defined intimal dissection and preserved anterograde flow is the least common finding. Occasionally, this injury causes partial obstruction with eventual thrombus formation, which can partially or completely occlude the main artery and extend into its branches. The lack of reliable criteria for diagnosis of these asymptomatic injuries results in diagnosis only after renal infarction.
Spiral CT angiography is the preferred imaging modality for identifying renal parenchymal injury in a stable trauma patient and it may lead to early diagnosis and should serve as a triage study to identify patients needing further investigation with angiography for diagnosis and possible treatment. Selective renal angiography was essential to evaluate the extent of dissection and suitability for repair. The anticipation of thrombosis and subsequent nephrectomy is the rationale for reconstruction of a patent renal artery with an intimal defect but percutaneous stent implantation provides a minimally invasive option for urgent intervention in a critically patient that represents a high surgical risk.

Differential Diagnosis List

Final Diagnosis

Traumatic renal artery dissection.

URL:	https://www.eurorad.org/case/7162
DOI:	10.1594/EURORAD/CASE.7162
ISSN:	1563-4086