Advanced Coronary Imaging: OCT, IVUS and FFR

Why look beyond the angiogram?

An angiogram is a shadow picture of the artery. It shows how narrow the channel looks, but it cannot always tell how much a narrowing actually reduces blood flow, or what the artery wall looks like. Three tools add that detail. All are used in the cath lab during coronary angiography or angioplasty.

The three tools

• FFR (fractional flow reserve): a very thin pressure wire is passed beyond the narrowing. It compares the pressure before and after it, and shows whether the narrowing actually limits blood flow. This helps decide whether a stent is needed or whether medicines are enough.
• IVUS (intravascular ultrasound): a tiny ultrasound probe on a catheter shows the artery wall from inside, the true size of the vessel and how much plaque is present.
• OCT (optical coherence tomography): uses light instead of sound, giving very detailed pictures of the inner lining and of a stent after it is placed.

What you may notice

Most people notice little difference from a routine angiogram. For FFR, a medicine may be given to widen the small vessels of the heart; it can cause a brief feeling of warmth, breathlessness or chest tightness that settles quickly. OCT needs a short flush of contrast to clear blood from the artery while pictures are taken.

How the results help

• Avoiding a stent in a narrowing that does not limit flow.
• Choosing the right stent size and length.
• Checking that the stent is fully expanded and well placed, which matters especially in complex procedures such as left main stenting.

Preparation and recovery

These are the same as for angiography or angioplasty. Tell the doctor in advance about asthma, kidney disease, diabetes medicines and allergies. If you are being evaluated for angina, bring your stress test and earlier reports.

Whether any of these tests is needed is decided during your procedure, based on the findings and your reports. This page is for understanding, not a substitute for consultation.