RADIOLOGY / DSA
Digital subtraction angiography (DSA)
Created 03/05/2021, last revision 21/05/2022
Digital subtraction angiography (DSA) is a fluoroscopic technique used for visualizing the vascular system. Structures such as bones are digitally subtracted from the image, which allows a better depiction of the blood vessels.
Indications
IndicationsAcute and elective therapeutic endovascular procedures
- acute stroke endovascular treatment (EVT)
- IA thrombolysis (IAT)
- mechanical thrombectomy (MT) → more
- local intra-sinus thrombolysis in patients with cerebral sinus thrombosis → more
- angioplasty and stenting of extra- or intracranial stenoses → carotid angioplasty with stenting
- endovascular treatment of malformations (AVM, DAVF) and aneurysms
Diagnosis of cerebral vascular diseases
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Functional tests
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Detection of circulatory arrest in brain death diagnosis
→ see here
Contraindications
Most contraindications are relative ⇒ assess risk-benefit
- contrast agent related contraindications
- renal insufficiency (laboratory results need to be obtained prior to the examination)
- eGFR should be > 30 mL/min in patients receiving iodinated contrast
- discretion should be used in patients with eGFR < 45 mL/min
- following injections with extra fluids is highly recommended
- hypersensitivity to iodinated contrast media
- reactions to contrast media are not a true allergy, but rather a pseudoallergy in nature (there is no allergic antibody present)
- contrast media act to directly release histamine and other chemicals from mast cells. The iodine concentration has an effect on the severity of an adverse reaction. The higher the iodine concentration, the greater the risk of an adverse reaction
- severe, life-threatening reactions, including anaphylaxis, occur in approx. 0.1% of people receiving contrast media
- renal insufficiency (laboratory results need to be obtained prior to the examination)
- pregnancy (relative contraindication with acute therapeutic procedures)
- blood clotting disorders and use of anticoagulant drugs
- unstable cardiopulmonary/neurological status
Procedure
Preprocedural evaluation
- check:
- personal medical history (presence of atherosclerotic disease, diabetes, renal dysfunction, etc.)
- allergies and previous exposure to iodinated contrast media
- prior vascular procedures
- review relevant vascular imaging studies (CTA, MRA, neurosonology)
- the patient should be fasting (> 4h, except for acute interventions)
- secure adequate hydration (nephropathy prevention)
- in diabetic patients, do not administer peroral antidiabetics (metformin) in the morning
- insert an intravenous cannula and urinary catheter
- the patient must be fully informed about the procedure and sign an informed consent
Principles of contrast agent administration and allergy premedication
→ see here
Monitoring during examination
- the angio suite should be equipped with monitor and crash cart
- standard monitoring during diagnostic DSA
- heart rate
- blood oxygenation (pulse oximetry)
- blood pressure (intermittently via a self-inflating cuff)
- an anesthesiologist should be available if sedation or general anesthesia (GA) are demanded
Procedural technique
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Postprocedural care
- bed rest for at least 4-6 h in the supine position
- careful compression and monitoring of the puncture site and peripheral blood supply
- blood pressure monitoring
- adequate hydration
Complications
- risk of a permanent neurological deficit following diagnostic DSA is low (0.09-0.14%)
- increased risk is related to endovascular procedures (thrombectomy, coiling, stenting, etc
→ local and systemic complications of endovascular procedures