Angiography-guided PCI has considerable limitations. On the other hand, the superior spatial resolution of OCT can provide meaningful clinical benefits. A recent study determined the effect on long-term survival of using OCT during PCI. The cohort study was based on the pan-London (United kingdom) PCI registry. OCT was used in 1.3% patients, intravascular ultrasound (IVUS) was used in 12.6% patients, and angiography alone in the remaining patients. OCT-guided procedures were associated with greater procedural success rates and reduced in-hospital MACE rates. A significant difference in mortality was observed between patients undergoing OCT-guided PCI (7.7%) compared to patients who underwent either IVUS-guided (12.2%) or angiography-guided (15.7%) PCI, with differences noted for both elective and acute coronary syndrome subgroups. This large observational study suggested that OCT-guided PCI was associated with improved procedure outcomes, in hospital events, and long-term survival in comparison with standard angiography-guided PCI.

The current consensus of on PCI states that the large final stent area offers the best chance of good late clinical outcome. OCT yields more accurate information about the coronary artery and implanted stents. As a result, OCT-guided stent implantation is expected to achieve greater stent expansion than angiography guidance alone.

The COCOA (Comparison between Optical COherence tomography guidance and angiography guidance to percutaneous coronary intervention) study is underway that aims to evaluate whether OCT-guided stent implantation would result in a minimum stent area greater than that achieved with angiography guidance alone. The study, completion, will contribute to define the clinical value of the OCT guidance in PCI.