What is an angiogram procedure?

Angiogram Procedure: A Comprehensive Guide

An angiogram is a diagnostic procedure that uses contrast dye and X-ray imaging to visualize blood vessels, detect abnormalities, and guide therapeutic interventions. It remains the gold standard for detailed vascular imaging despite advances in non-invasive techniques.

Procedure Overview

• Angiography is performed by inserting a catheter into an artery (typically femoral, but sometimes radial or brachial), advancing it to the target vessel, and injecting contrast dye while taking X-ray images 1
• The procedure creates detailed images of blood vessels, allowing visualization of abnormalities such as stenosis, occlusions, aneurysms, and active bleeding 1
• Conventional angiography provides high-resolution, three-dimensional pathoanatomical data about vasculature and allows real-time analysis of blood flow 2

Types of Angiography

• Cerebral angiography: Evaluates brain vessels for aneurysms, arteriovenous malformations, and stenosis; essential in stroke management 1
• Coronary angiography: Assesses coronary arteries for stenosis, occlusions, and anomalies; often performed with ventriculography 1
• Pulmonary angiography: Evaluates pulmonary circulation; used in pulmonary embolism and pulmonary hypertension assessment 1
• Peripheral angiography: Examines vessels in the extremities for peripheral vascular disease 1
• Visceral angiography: Evaluates abdominal vessels for bleeding, aneurysms, or tumor vascularity 1, 3

Clinical Applications

• Diagnostic purposes:

  • Detection of vascular abnormalities (aneurysms, stenosis, occlusions) 1
  • Evaluation of active bleeding sites requiring at least 0.5-1.0 mL/min bleeding rate for detection 1
  • Assessment of vascular anatomy before surgical procedures 1

• Therapeutic interventions:

  • Embolization of bleeding vessels or vascular malformations 1
  • Balloon angioplasty and stent placement for stenotic vessels 1, 4
  • Intra-arterial delivery of medications (vasopressin, thrombolytics) 1, 4
  • Mechanical thrombectomy for acute ischemic stroke 1, 2

Advantages and Limitations

Advantages:

• Highest spatial and temporal resolution for vascular imaging 1, 2
• Ability to perform therapeutic interventions during the same procedure 1
• Real-time visualization of blood flow dynamics 1, 2
• Gold standard for detecting certain vascular abnormalities like angiodysplasia 1

Limitations:

• Invasive procedure with 1-2% risk of complications including stroke and dissection 1
• Exposure to ionizing radiation and iodinated contrast material 2, 5
• Requires specialized equipment and trained personnel 1, 2
• Limited ability to diagnose certain conditions like intramural hematoma 1

Preparation and Procedure Steps

• Patient preparation includes fasting for several hours, assessment of renal function, and discontinuation of certain medications 1
• The procedure is typically performed under local anesthesia with conscious sedation 1, 2
• The target artery is accessed using the Seldinger technique, and a sheath is placed 1
• Catheters are advanced to the target vessels under fluoroscopic guidance 1
• Contrast dye is injected while X-ray images are acquired 1
• For therapeutic interventions, additional devices (balloons, stents, embolization materials) may be deployed 1, 4
• After the procedure, the catheter is removed, and hemostasis is achieved 1

Complications

• Major complications (occur in approximately 1% of cases):

  • Stroke or embolism 1, 2
  • Arterial dissection or perforation 1
  • Severe allergic reaction to contrast 1, 2

• Minor complications:

  • Access site hematoma or bleeding 1, 2
  • Contrast-induced nephropathy 1, 2
  • Vasovagal reactions 1
  • Transient neurological symptoms 1, 2

Alternative Imaging Modalities

• CT Angiography (CTA): Less invasive alternative with good spatial resolution; limitations include radiation exposure and contrast requirements 1, 3
• MR Angiography (MRA): Non-invasive option without radiation; useful for patients with contrast allergies or renal insufficiency; limitations include lower spatial resolution and longer acquisition times 1, 6, 5
• Duplex Ultrasonography: Non-invasive option for peripheral vessels; limited by operator dependence and inability to visualize deep vessels 6

Despite advances in non-invasive imaging techniques, conventional angiography remains the reference standard for vascular imaging due to its superior spatial resolution and the ability to perform therapeutic interventions 1, 2.