Angiography, Carotid

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Angiography, Carotid

Synonym/acronym: Carotid angiogram, carotid arteriography.

Common use

To visualize and assess the carotid arteries and surrounding tissues for abscess, tumors, aneurysm, and evaluate for atherosclerotic disease related to stroke risk.

Area of application

Neck/cervical area.

Contrast

Iodine based.

Description

This test evaluates blood vessels in the neck carrying arterial blood to the brain and is accomplished by the injection of contrast material through a catheter that has been inserted into the femoral artery. Fluoroscopy is used to guide catheter placement and angiograms (high-speed x-ray images) provide images of the carotid artery and associated vessels in surrounding tissue which are displayed on a monitor and are recorded for future viewing and evaluation. Digital subtraction angiography (DSA) is a computerized method of removing undesired structures, like bone, from the surrounding area of interest. A digital image is taken prior to injection of the contrast and then again after the contrast has been injected. By subtracting the preinjection image from the postinjection image a higher-quality, unobstructed image can be created. The x-ray equipment is mounted on a C-shaped arm with the x-ray device beneath the table on which the patient lies. Over the patient is an image intensifier that receives the x-rays after they pass through the patient. Patterns of circulation or changes in vessel wall appearance can be viewed to help diagnose the presence of vascular abnormalities, disease, narrowing, enlargement, blockage, trauma, or lesions. This definitive test for arterial disease may be used to evaluate chronic vascular disease, arterial or venous stenosis, and medical therapy or surgery of the vasculature. Catheter angiography still is used in patients who may undergo surgery, angioplasty, or stent placement.

This procedure is contraindicated for

  • high alertPatients who are pregnant or suspected of being pregnant, unless the potential benefits of a procedure using radiation far outweigh the risk of radiation exposure to the fetus and mother.
  • high alertConditions associated with adverse reactions to contrast medium (e.g., asthma, food allergies, or allergy to contrast medium). Although patients are still asked specifically if they have a known allergy to iodine or shellfish (shellfish contain high levels of iodine), it has been well established that the reaction is not to iodine; an actual iodine allergy would be very problematic because iodine is required for the production of thyroid hormones. In the case of shellfish the reaction is to a muscle protein called tropomyosin; in the case of iodinated contrast medium the reaction is to the noniodinated part of the contrast molecule. Patients with a known hypersensitivity to the medium may benefit from premedication with corticosteroids and diphenhydramine; the use of nonionic contrast or an alternative noncontrast imaging study, if available, may be considered for patients who have severe asthma or who have experienced moderate to severe reactions to ionic contrast medium.
  • high alertConditions associated with preexisting renal insufficiency (e.g., renal failure, single kidney transplant, nephrectomy, diabetes, multiple myeloma, treatment with aminoglycocides and NSAIDs) because iodinated contrast is nephrotoxic.
  • high alertElderly and compromised patients who are chronically dehydrated before the test because of their risk of contrast-induced renal failure.
  • high alertPatients with pheochromocytoma because iodinated contrast may cause a hypertensive crisis.
  • high alertPatients with bleeding disorders or receiving anticoagulant therapy because the puncture site may not stop bleeding.

Indications

  • Aid in angioplasty, atherectomy, or stent placement
  • Allow infusion of thrombolytic drugs into an occluded artery
  • Detect arterial occlusion, which may be evidenced by a transection of the artery caused by trauma or penetrating injury
  • Detect artery stenosis, evidenced by vessel dilation, collateral vessels, or increased vascular pressure
  • Detect nonmalignant tumors before surgical resection
  • Detect tumors and arterial supply, extent of venous invasion, and tumor vascularity
  • Detect thrombosis, arteriovenous fistula, aneurysms, or emboli in vessels
  • Evaluate placement of a stent
  • Differentiate between tumors and cysts
  • Evaluate tumor vascularity before surgery or embolization
  • Evaluate the vascular system of prospective organ donors before surgery

Potential diagnosis

Normal findings

  • Normal structure, function, and patency of carotid arteries
  • Contrast medium normally circulates throughout neck symmetrically and without interruption
  • No evidence of obstruction, variations in number and size of vessels, malformations, cysts, or tumors

Abnormal findings related to

  • Abscess or inflammation
  • Arterial stenosis or dysplasia
  • Aneurysms
  • Arteriovenous fistula or other abnormalities
  • Congenital anomalies
  • Cysts or tumors
  • Trauma causing tears or other disruption
  • Vascular blockage or other disruption

Critical findings

    N/A

Interfering factors

  • Factors that may impair clear imaging

    • Gas or feces in the gastrointestinal tract resulting from inadequate cleansing or failure to restrict food intake before the study.
    • Retained barium from a previous radiological procedure.
    • Metallic objects within the examination field (e.g., jewelry, body rings), which may inhibit organ visualization and can produce unclear images.
    • Inability of the patient to cooperate or remain still during the procedure because of age, significant pain, or mental status.
  • Other considerations

    • Consultation with a health-care provider (HCP) should occur before the procedure for radiation safety concerns regarding younger patients or patients who are lactating. Pediatric & Geriatric Imaging Children and geriatric patients are at risk for receiving a higher radiation dose than necessary if settings are not adjusted for their small size. Pediatric Imaging Information on the Image Gently Campaign can be found at the Alliance for Radiation Safety in Pediatric Imaging (www.pedrad.org/associations/5364/ig/).
    • Risks associated with radiation overexposure can result from frequent x-ray procedures. Personnel in the room with the patient should wear a protective lead apron, stand behind a shield, or leave the area while the examination is being done. Personnel working in the examination area should wear badges to record their level of radiation exposure.
    • Failure to follow dietary restrictions and other pretesting preparations may cause the procedure to be canceled or repeated.

Nursing Implications and Procedure

Pretest

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this procedure can assist with evaluation of the cardiovascular system.
  • Obtain a history of the patient’s complaints or clinical symptoms, including a list of known allergens, especially allergies or sensitivities to latex, anesthetics, contrast medium, or sedatives.
  • Obtain a history of the patient’s cardiovascular system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures. Ensure results of coagulation testing are obtained and recorded prior to the procedure; a creatinine level is also needed before contrast medium is to be used.
  • Note any recent procedures that can interfere with test results, including examinations using iodine-based contrast medium or barium. Ensure that barium studies were performed more than 4 days before angiography.
  • Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
  • Obtain a list of the patient’s current medications, including anticoagulants, aspirin and other salicylates, herbs, nutritional supplements, and nutraceuticals, especially those known to affect coagulation (see Effects of Natural Products on Laboratory Values online at DavisPlus). Such products should be discontinued by medical direction for the appropriate number of days prior to a surgical procedure. Note the last time and dose of medication taken.
  • If iodinated contrast medium is scheduled to be used in patients receiving metformin (Glucophage) for non-insulin-dependent (type 2) diabetes, the drug should be discontinued on the day of the test and continue to be withheld for 48 hr after the test. Iodinated contrast can temporarily impair kidney function, and failure to withhold metformin may indirectly result in drug-induced lactic acidosis, a dangerous and sometimes fatal side effect of metformin (related to renal impairment that does not support sufficient excretion of metformin).
  • Review the procedure with the patient. Address concerns about pain and explain that there may be moments of discomfort and some pain experienced during the test. Inform the patient that the procedure is usually performed in a radiology or vascular suite by an HCP and takes approximately 30 to 60 min.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Explain that an IV line may be inserted to allow infusion of IV fluids such as normal saline, anesthetics, sedatives, or emergency medications. Explain that the contrast medium will be injected, by catheter, at a separate site from the IV line.
  • Inform the patient that a burning and flushing sensation may be felt throughout the body during injection of the contrast medium. After injection of the contrast medium, the patient may experience an urge to cough, flushing, nausea, or a salty or metallic taste.
  • Instruct the patient to remove jewelry and other metallic objects from the area to be examined.
  • Instruct the patient to fast and restrict fluids for 2 to 4 hr prior to the procedure. Protocols may vary among facilities.
  • This procedure may be terminated if chest pain, severe cardiac arrhythmias, or signs of a cerebrovascular accident occur.
  • Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.

Intratest

  • Potential complications:
  • Establishing an IV site and injection of contrast medium by catheter are invasive procedures. Complications are rare but do include risk for: allergic reaction (related to contrast reaction); bleeding from the puncture site (related to a bleeding disorder, or the effects of natural products and medications known to act as blood thinners—postprocedural bleeding from the site is rare because at the conclusion of the procedure a resorbable device, composed of non-latex-containing arterial anchor, collagen plug, and suture, is deployed to seal the puncture site); blood clot formation (related to thrombus formation on the tip of the catheter sheath surface or in the lumen of the catheter—the use of a heparinized saline flush during the procedure decreases the risk of emboli); hematoma (related to blood leakage into the tissue following needle insertion); infection (that might occur if bacteria from the skin surface is introduced at the puncture site); tissue damage (related to extravasation of the contrast during injection); or nerve injury or damage to a nearby organ (which might occur if the catheter strikes a nerve or perforates an organ).

  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
  • Ensure the patient has complied with dietary, fluid, and medication restrictions and pretesting preparations.
  • Ensure the patient has removed all external metallic objects from the area to be examined.
  • Administer ordered prophylactic steroids or antihistamines before the procedure. Use nonionic contrast medium for the procedure if the patient has a history of allergic reactions to any susbstance or drug.
  • Have emergency equipment readily available.
  • Instruct the patient to void prior to the procedure and to change into the gown, robe, and foot coverings provided.
  • Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still throughout the procedure because movement produces unreliable results.
  • Record baseline vital signs, and assess neurological status. Protocols may vary among facilities.
  • Establish an IV fluid line for the injection of saline, sedatives, or emergency medications.
  • Administer an antianxiety agent, as ordered, if the patient has claustrophobia. Administer a sedative to a child or to an uncooperative adult, as ordered.
  • Place electrocardiographic electrodes on the patient for cardiac monitoring. Establish a baseline rhythm; determine if the patient has ventricular arrhythmias.
  • Using a pen, mark the site of the patient’s peripheral pulses before angiography; this allows for quicker and more consistent assessment of the pulses after the procedure.
  • Place the patient in the supine position on an examination table. Cleanse the selected area, and cover with a sterile drape.
  • A local anesthetic is injected at the site, and a small incision is made or a needle is inserted under fluoroscopy.
  • The contrast medium is injected, and a rapid series of images is taken during and after the filling of the vessels to be examined. Delayed images may be taken to examine the vessels after a time and to monitor the venous phase of the procedure.
  • Instruct the patient to inhale deeply and hold his or her breath while the images are taken, and then to exhale after the images are taken.
  • Instruct the patient to take slow, deep breaths if nausea occurs during the procedure.
  • Monitor the patient for complications related to the procedure (e.g., allergic reaction, anaphylaxis, bronchospasm).
  • The needle or catheter is removed, and a pressure dressing is applied over the puncture site.
  • Observe/assess the needle/catheter insertion site for bleeding, inflammation, or hematoma formation.

Post-Test

  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Instruct the patient to resume usual diet, fluids, medications, or activity, as directed by the HCP. Renal function should be assessed before metformin is resumed.
  • Monitor vital signs and neurological status every 15 min for 1 hr, then every 2 hr for 4 hr, and as ordered. Take temperature every 4 hr for 24 hr. Monitor intake and output at least every 8 hr. Compare with baseline values. Protocols may vary from facility to facility.
  • Observe for delayed allergic reactions, such as rash, urticaria, tachycardia, hyperpnea, hypertension, palpitations, nausea, or vomiting.
  • Instruct the patient to immediately report symptoms such as fast heart rate, difficulty breathing, skin rash, itching, chest pain, persistent right shoulder pain, or abdominal pain. Immediately report symptoms to the appropriate HCP.
  • Assess extremities for signs of ischemia or absence of distal pulse caused by a catheter-induced thrombus.
  • Observe/assess the needle/catheter insertion site for bleeding, inflammation, or hematoma formation.
  • Instruct the patient in the care and assessment of the site.
  • Instruct the patient to apply cold compresses to the puncture site as needed, to reduce discomfort or edema.
  • Instruct the patient to maintain bedrest for 4 to 6 hr after the procedure or as ordered.
  • Recognize anxiety related to test results, and be supportive of perceived loss of independent function. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
  • Instruct the patient in the use of any ordered medications. Explain the importance of adhering to the therapy regimen. As appropriate, instruct the patient in significant side effects and systemic reactions associated with the prescribed medication. Encourage him or her to review corresponding literature provided by a pharmacist.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

  • Related tests include angiography abdomen, BUN, CT angiography, CT brain, creatinine, ECG, exercise stress test, MRA, MRI brain, PT/INR, plethysmography, US arterial Doppler lower extremities, and US peripheral Doppler.
  • See the Cardiovascular System table at the end of the book for related tests by body system.
References in periodicals archive ?
TORONTO -- High-resolution magnetic resonance imaging is potentially a better way to assess carotid plaque than is conventional carotid arteriography or ultrasound, Dr.