When it comes to looking inside the arteries supplying the muscles of the heart (coronary arteries), two imaging modalities come into play. They are angiography and OCT (optical coherence tomography).
Angiography
During an angioplasty, a stent is used to open the blocked blood vessel. When doing an angiography (angiogram), a doctor injects a dye into the vessels to make them visible on an X-ray. Despite being the most popular, angiograms have a number of disadvantages. The resolution of their two-dimensional images is low. Angiography cannot provide a glimpse into the vessel. Additionally, there is a chance that the stent won’t be inflated or positioned properly.
OCT
Optical Coherence Tomography (OCT) is a contemporary imaging technique for cardiac problems that produces high-resolution 3D pictures. It enables a precise assessment of the vascular lumen and stent by providing good image quality with swift pull-back speeds, procedural safety, and patient acceptability. OCT offers distinct insights into stenting techniques that could otherwise go unnoticed when compared to IVUS (Intravascular Ultrasound) or traditional angiography. Compared to angiography images, OCT images have a resolution that is more than 20 times higher. Furthermore, compared to ultrasound, the resolution is more than ten times higher1.
There is plenty of clinical evidence in support of OCT. About 90% of treating clinicians’ procedure decisions were altered by OCT-guided angioplasty (PCI). The prevalence of myocardial infarctions was shown to be lower when OCT guidance was used. Additionally, the OCT-guided stent expansion process is superior to the angiographic approach.
The clinical value of OCT
OCT can help a patient in a variety of ways. OCT’s 3D images enable medical professionals to adapt their treatment plans. It helps to lower the hazards that are present. By performing an OCT, the patient avoids needless procedures or operations. Additionally, it gives doctors the ability to enhance clinical processes and outcomes.
Interventional cardiologists employ OCT as a supplemental technique for assessing atherosclerotic plaques (blockages) and coronary angioplasty direction and optimization (stenting). High-resolution imaging of the shape and composition of coronary atherosclerotic plaques enables the identification of vulnerable plaques that are very susceptible to acute alteration, which could result in heart attacks and sudden death.
OCT gives interventional cardiologists comprehensive knowledge of coronary stenosis, enabling careful “tailoring” of the stent to provide the patient with the greatest short- and long-term outcomes. There is plenty of obtainable information during the pre-stenting stage too. By using OCT, cardiologists can optimise the post-stenting result to ensure favourable long-term outcomes by post-stenting evaluating the angioplasty result and potential problems.
In summary,
OCT opens the door to a hitherto uncharted universe by providing in vivo data on atherosclerotic plaque morphology with near-light microscopy resolution. The high resolution of this imaging method allows for a thorough assessment of coronary atherosclerotic plaques as well as the vascular response to coronary interventional devices, such as new generation coronary stents. OCT can also be utilised as more accurate guidance for coronary intervention than traditional angiography or intravascular ultrasonography coronary imaging.
References
- Prati F, Guagliumi G, Mintz GS, et al. Expert review document part 2: Methodology, terminology and clinical applications of optical coherence tomography for the assessment of interventional procedures. Eur Heart J. 2012;33(20). doi:10.1093/EURHEARTJ/EHS095
- Optical coherence tomography for coronary imaging. Accessed September 24, 2022. https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-9/Optical-coherence-tomography-for-coronary-imaging
