Renal Artery Aneurysm Workup

Updated: Oct 23, 2019
  • Author: Lindsay Gates, MD; Chief Editor: Vincent Lopez Rowe, MD  more...
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Workup

Laboratory Studies

The following studies should be performed before any surgical intervention for a renal artery aneurysm (RAA):

  • Complete blood count (CBC)
  • Chemistry panel
  • Coagulation profile
  • Urinalysis 

Special attention should be paid to the blood urea nitrogen (BUN) and creatinine levels because these values are indicative of renal function and can be followed to confirm that no renal damage exists if the decision is made to manage an RAA nonoperatively.

In a patient with hypertension, RAA, and no renal artery stenosis, studies should be ordered to exclude other endocrine sources of hypertension, including the following:

  • Pheochromocytoma - 24-hour urine collection for vanillylmandelic acid, metanephrine, and normetanephrine
  • Primary aldosteronism - Serum potassium
  • Cushing syndrome - Cortisol levels
  • Carcinoid - Urinary 5-hydroxyindoleacetic acid
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Imaging Studies

Because most RAAs are asymptomatic and are found incidentally during a workup for other intra-abdominal pathology, imaging studies are required only for preintervention planning or longitudinal follow-up care.

Ultrasonography

Ultrasonography (US) with duplex examination is the least invasive imaging study. [38] Two-dimensional (2D) US forms an anatomic picture based on the time delay of ultrasonic pulses reflected from structures. Vessel walls reflect ultrasound waves and appear white; blood absorbs and scatters ultrasound waves, appearing black. Normal vessels appear as dark-filled, white-walled structures.

Duplex studies use Doppler-shift measurement to detect the direction and velocity of blood flow. This can be useful in identifying renal artery stenosis. US can also be used in determining the how functional a kidney is by measuring its size. It should be kept in mind that the quality of imaging is highly operator-dependent and may be limited by the patient's body habitus.

Computed tomography

Computed tomography (CT) is the most widely available and reproducible imaging modality. It is the test of choice for diagnosis and follow-up. Its anatomic resolution is superior to that of US (see the image below).

(A) Computed tomography scan and (B) arteriogram o (A) Computed tomography scan and (B) arteriogram of the same patient with a saccular left renal artery aneurysm at a segmental renal artery branch.

The advent of CT angiography (CTA) and three-dimensional (3D) reconstruction has facilitated accurate preinterventional planning. Because intravenous (IV) iodinated dye must be used, the only real limitation of this modality is in patients who have a life-threatening dye allergy or impaired renal function. Non-life-threatening dye allergies can be managed with premedication with diphenhydramine (histamine-1 receptor antagonist), cimetidine (histamine-2 receptor antagonist), and methylprednisolone sodium succinate (glucocorticoid).

Magnetic resonance angiography

Magnetic resonance angiography (MRA) with gadolinium enhancement and 3D reconstruction can produce images similar in quality to those obtained with arteriography (see the image below). However, this technology is not as readily available as US or CT, and it is more expensive. [39]

Magnetic resonance imaging of a patient with 2 lef Magnetic resonance imaging of a patient with 2 left renal artery aneurysms. Both are saccular, one is at a segmental branch (closed arrow) and the other is intrarenal (open arrow). Of note: this patient also has a congenital absence of the right kidney.

Arteriography

Arteriography is the most invasive test but can be useful for helping define unclear anatomy seen on prior examinations (see the images below). For the most part, arteriography as a diagnostic test has been supplanted by CTA and MRA.

(A) Aortogram with calcified left renal artery ane (A) Aortogram with calcified left renal artery aneurysm (RAA). (B-C) Same RAA in magnified view, demonstrating the RAA is saccular, arising from the main renal artery.
(A) Computed tomography scan and (B) arteriogram o (A) Computed tomography scan and (B) arteriogram of the same patient with a saccular left renal artery aneurysm at a segmental renal artery branch.
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