CO2 Angiography

What is angiography?

Angiography is a radiological examination that allows doctors to visualise blood vessels and diagnose problems such as narrowings, blockages, or malformations. It is also used for interventional purposes, enabling direct treatment of issues identified during the diagnostic phase. During the procedure, a contrast agent is injected into the bloodstream to make the vessels visible on X-rays. 

Limitations of iodinated contrast media

The contrast agent most commonly used in angiography contains iodine. Although effective, iodinated contrast can cause significant problems in many patients:

  • Kidney damage: iodine-based contrast is one of the leading causes of contrast-induced nephropathy (CIN), especially in patients with pre-existing renal impairment, high creatinine levels and/or low eGFR.
  • Allergic reactions: reactions can range from mild (itching, nausea) to severe (breathing difficulties, anaphylactic shock).
  • Liver concerns: it may be risky for patients with liver diseases.
  • Limited repeatability: due to its cumulative toxicity, the exam cannot be repeated frequently, reducing opportunity to closely monitor one’s clinical conditions.

For these reasons, certain patient groups may face limitations or increased risks when undergoing traditional angiography. 

CO2 angiography: the safe alternative 

Carbon dioxide (CO2) is the safe and effective alternative to iodinated contrast. Since CO2 is a natural gas already present in the human body, it is the only contrast agent that does not cause adverse reactions.

  • No risk to the kidneys: CO2 doesn't pass through the kidneys but is expelled from the body via the lungs, thus eliminating the risk of contrast-induced nephropathy. It's therefore the ideal option for patients with renal impairment or on dialysis, and helps preserve kidney function even in patients with healthy kidneys.
  • No allergic reactions: being 100% biocompatible, CO2 does not trigger allergic responses.
  • No liver complications: it can be safely used in patients with liver diseases.
  • Safe for repeated exams: thanks to its biocompatibility, CO2 allows angiography to be performed with high frequency and without limits on the quantity of gas administered during the same examination.
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Where CO2 can be used

CO2 angiography is suitable for a wide range of vascular areas.

  • In the arterial system, it can be used in all arteries below the diaphragm, such as the abdominal aorta, renal, mesenteric, iliac, and lower-limb arteries.
  • In the venous system, it is safe for all veins below the neck, including abdominal, pelvic, and lower-limb areas.
  • CO2 angiography is also particularly recommended for the creation and maintenance of arteriovenous fistulas for hemodialysis.

Important: CO2 must not be used in arterial vessels above the diaphragm (such as coronary, carotid, or cerebral arteries) due to the risk of gas embolism.

Who CO2 angiography is for

CO2 angiography is the ideal choice if you:

  • Have kidney problems or renal impairment
  • Have high creatinine levels or low eGFR
  • Are allergic to iodinated contrast
  • Have liver diseases
  • Need to undergo angiographic examinations frequently
  • Have experienced adverse reactions to iodinated contrast in the past

Whilst safe for most people, CO₂ use is not advisable if you suffer from severe pulmonary insufficiency or have pulmonary arteriovenous malformations.