What are IVUS and OCT?
Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) are advanced imaging techniques used during coronary angiography to provide high-resolution, real-time images of the inside of coronary arteries. These tools allow cardiologists to assess the severity of artery narrowing (stenosis), guide stent placement, and evaluate the success of treatments such as angioplasty and stenting.
While a standard coronary angiogram uses X-ray and contrast dye to outline the arteries, IVUS and OCT provide detailed cross-sectional images, offering a more precise assessment of the artery walls and plaques.
How Do IVUS and OCT Work?
• IVUS uses sound waves (ultrasound) emitted from a tiny probe on a catheter inserted into the artery. It provides deep tissue imaging, showing plaque composition and artery thickness.
• OCT uses near-infrared light, which creates ultra-high-resolution images, allowing cardiologists to see even small details like the thin fibrous caps over plaques.
Both imaging technologies help cardiologists make informed decisions about whether to place a stent, how to position it correctly, and whether further interventions are needed.
Why Might You Need IVUS or OCT?
Dr Amin may recommend IVUS or OCT if:
• Your coronary angiogram shows a moderate narrowing, and more detail is needed to determine if treatment is necessary.
• You have complex coronary artery disease, including heavily calcified or irregular plaques.
• You are undergoing angioplasty and stenting, and the doctor needs to ensure the stent is optimally placed.
• Your previous stent is being evaluated for potential re-narrowing (in-stent restenosis) or improper expansion.
• You have left main artery disease, where treatment decisions require high precision.
These imaging tools help avoid unnecessary procedures while ensuring that necessary interventions are performed accurately.
How to Prepare for the Procedure?
These imaging modalities are performed as part of a coronary angiogram, so the preparation is the same. Before undergoing a coronary angiography, Dr Amin will provide some specific instructions either in clinic consultation or over the phone if you are referred by a colleague. Here are some general guidelines:
• Consenting: Dr Amin will provide you a detailed discussion regarding the procedure steps, benefits and risks of the procedure. This can be done in a face to face consultation or over the phone if you have been referred for the procedure. You will need to sign a formal consent form on the day before attempting the procedure. If you have any questions, Dr Amin would be happy to discuss at any point before the day.
• Fasting: This is not indicated in most of cases unless there would be an indication for deep sedation or anaesthetics requirements. You may need to stop eating and drinking for a few hours before the procedure.
• Medications: Inform Dr Amin about all medications you are taking, especially blood thinners, diabetes medications, or any drugs that affect kidney function. Dr Amin might give you instructions to stop some medications particularly strong blood thinners such as Apixaban, Rivaroxaban or Edoxaban only on the day of the procedures. If you are diabetic, metformin might need to be stopped in certain cases.
• Allergies: Let your doctor know if you have allergies, particularly to iodine, shellfish, or contrast dye.
• Kidney Function: Since the contrast dye is filtered through the kidneys, patients with kidney disease may need additional precautions. Dr Amin or the admin team at the Great Western Hospitals Private Healthcare in Swindon might arrange for kidney function test ahead of the procedure. If the procedure is arranged at a short notice, bloods can be taken on the day.
What Happens During the procedure?
1. Preparation
You will be asked to attend the Cardiac Cath Lab suite at the Great Western Hospital in Swindon early on the day usually 08:00. You will be met by our friendly nursing team who will guide you regarding preparation and will fill in a questionnaire for the procedure including medical history and medications. A cannula will be inserted in one of your veins in case you need medications to be given.
Dr Amin will meet you to discuss if you have any questions and to go briefly through the details of the procedure for recap. You will be asked to sign a consent form if you have not done earlier. There would be an opportunity to discuss any concerns and ask questions regarding the procedure and possible outcomes.
You will be taken to a catheterization lab, where you will lie on a special X-ray table. A nurse will clean and shave the area where the catheter (a thin, flexible tube) will be inserted – usually the wrist (radial artery) or groin (femoral artery). A local anaesthetic is applied to numb the area.
2. Coronary Angiography and Catheter Insertion
• A catheter is inserted through the wrist (radial artery) or groin (femoral artery) and guided into the coronary arteries.
• Contrast dye is injected, and X-ray images are taken to identify blockages.
3. Inserting the IVUS or OCT Catheter
• A special catheter with an imaging probe is inserted through the guidewire and positioned at the narrowed area.
4. Imaging the Artery
• For Intravascular Ultrasound, the catheter emits ultrasound waves, creating detailed cross-sectional images of the artery’s walls and plaque buildup.
• For Optical Coherence Tomography, the artery is flushed with contrast dye to clear blood, and near-infrared light scans the artery, providing ultra-high-resolution images of even the smallest structures.
5. Interpreting the Results
Dr Amin will do the following assessments:
• The thickness and composition of plaques (fatty deposits lining the vessels).
• Whether the artery needs a stent.
• If a stent has been placed, whether it is properly expanded and positioned.
Once imaging is complete, the catheter is removed, and a treatment plan is determined.
IVUS vs. OCT: What’s the Difference?
| Feature | IVUS | OCT |
| Technology | Ultrasound waves | Near-infrared light |
| Image Depth | Deeper tissue imaging, good for thick plaques | High-resolution surface imaging, ideal for stent assessment |
| Best for | Assessing large, complex plaques | Evaluating fine details of stents and thin plaques |
| Contrast Dye Use | Minimal | Requires contrast injection |
IVUS is often preferred for deep plaque analysis, while OCT is ideal for stent optimization
What Happens After the Procedure?
Recovery and Monitoring
• You will be provided with a detailed Coronary Angiogram and PCI report if stents are placed. This includes the details of your coronary anatomy, medications and equipments used as well as the contrast volume and radiation dose. The report will also include the conclusions and recommendations for management plan. Some reports will include captured images for your coronary vessels and stents placed.
• If the catheter was inserted through the wrist, you may be allowed to sit up sooner. If it was inserted through the groin, you may need to lie flat for a few hours.
• Your heart rate, blood pressure, and puncture site will be monitored for any complications.
• You may be advised to drink plenty of fluids to help flush the contrast dye from your kidneys.
Going Home
• Most patients can go home the same day, but someone should accompany you as you may not be able to drive.
• You should avoid heavy lifting or strenuous activities for a few days.
• It is normal to experience some bruising or mild discomfort at the catheter insertion site. If you notice excessive bleeding, swelling, or severe pain at the puncture site, contact Dr Amin immediately via the provided contact number. You may be asked to come back for checking by the Cath Lab team.
Benefits of IVUS and OCT
• More accurate diagnosis of plaque severity and composition.
• Reduces unnecessary stenting, ensuring only significant blockages are treated.
• Improves stent placement, reducing the risk of restenosis (re-narrowing).
• Guides treatment decisions, leading to better long-term outcomes.
What are the risks?
IVUS and OCT are very safe, with risks similar to those of a coronary angiogram, including:
• Bleeding or bruising at the catheter insertion site. The risk is higher if the groin access is used rather than the forearm.
• Allergic reaction to the contrast dye. This is rare complication and previous allergy to contrast should be notified before the procedure. If allergy is known, Dr Amin may still go ahead with the necessary precautions including administration of some medications to mitigate the risk.
• Blood vessel damage during catheter insertion
• Irregular heart rhythms (arrhythmias)
• Re-narrowing of the artery (restenosis), which may require another procedure
• Rare complications such as heart attack, stroke, or kidney problems
Death is a very rare scenario in diagnostic coronary angiography and the quoted risk is almost 1 in 4000 cases.
Dr Amin will discuss these risks with you and take steps to minimize them.
Frequently Asked Questions
1. Is IVUS or OCT painful?
No, the procedure itself is not painful. You may feel mild pressure when the catheter is inserted, but sedation is used to keep you comfortable.
2. How long does IVUS or OCT take?
The imaging process adds only 5-10 minutes to a standard coronary angiogram.
3. What happens if the test shows a significant blockage?
If the imaging confirms a severe blockage, your doctor may recommend angioplasty and stenting or, in some cases, bypass surgery.
4. Do IVUS and OCT replace traditional angiograms?
No, they are used alongside angiograms to provide more detailed information when needed.
Conclusion
IVUS and OCT are cutting-edge technologies that allow cardiologists to see inside your arteries with extreme precision. By using these advanced imaging techniques, doctors can make better treatment decisions, improve stent placement, and avoid unnecessary procedures.
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