Percutaneous coronary intervention (PCI) is a non-surgical procedure used to place a stent in the blocked heart artery, due to a factor (blood clot for example) that blocks the blood flow to the cardiac cells.

Angiography-guided PCI

To perform this type of intervention, an imaging technique using X-ray called Angiography is used to help visualizing heart’s blood arteries and guide stent selection and placement. However, it is not a straightforward method all the time.

Sometimes the blood clot location or where the lesion is (ex: coronary artery bifurcation lesions) makes the intervention quite challenging. A blood clot known as thrombus, can be formed in a distant artery branch, making it hard to reach. Moreover, Angiography lacks the ability to give a detailed look at the clot composition and distribution, provides limited information about coronary bifurcation anatomy, and does not inform well about how the stent is working in place, known as stent expansion and strut apposition.

Angiography-guided PCI is largely implemented until this day in many cardiac centers, especially for patients with simple coronary lesions. But this classic PCI method does not always secure good cardiac outcomes for patients with complex lesions. Further cardiovascular intervention may be needed for these patients at follow-up.

Optical coherence tomography-guided PCI

Optical coherence tomography (OCT) is an intravascular imaging technique that uses light waves to see inside blood vessels, providing high resolution images that automatically generate contoured lumen areas across the variable geometry of bifurcation lesions.

OCT outperforms the classic angiography in terms of dealing with the most complex coronary lesions.

- Better plaque location detection.
- Reliable evaluation of coronary anatomy, lumen area and lesion severity.
- Detailed assessment of blood clot composition and distribution.
- Approved planning of appropriate stent placement strategy.
- Accurate detection of stent expansion, stent strut malapposition, stent edge dissection.

Three New England journal of medicine studies, proved the effectiveness of OCT as guiding technique for better cardiovascular outcomes at follow-up.

The ILUMIEN IV study compared OCT-guided PCI to angiography-guided PCI in 2,487 people with diabetes or high-risk coronary lesions at 80 sites in 18 countries. OCT guidance resulted in a larger minimum stent area – the area opened up so blood could flow more freely – and appeared to be safe. Both methods were equally effective at preventing death, heart attacks or the need for further revascularization over two years of follow-up.

The OCTOBER trial compared these two methods for placing stents in 1,201 people in 38 centers in Europe who had complex coronary artery bifurcation lesions – plaque build-up in areas where arteries branch that are difficult to see. Over two years of follow-up, people who had OCT-guided PCI had fewer adverse major cardiac events and deaths than those whose stents were placed using angiography guidance. There was a similar rate of complications for both groups.

The RENOVATE-COMPLEX-PCI study compared intravascular imaging-guided PCI (either ultrasonography or OCT) to angiography-guided PCI for 1,639 patients in South Korea with complex coronary artery lesions. Over two years of follow-up, people treated with either type of intravascular imaging-guided PCI experienced fewer heart-related deaths, heart attacks or need for further revascularization than those whose PCI was guided by angiography. Complication rates were similar for both groups.

The OCTIVUS randomized, clinical trial, published in The American Heart Association (AHA) Circulation, compared the safety and effectiveness of the two types of intravascular image guidance in 2,008 patients with significant coronary artery lesions and found both were equally safe and effective.

OCT-guided PCI stands as an important advancement in cardiology, improving outcomes for heart patients with complex coronary diseases.

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