Optical Coherence Tomography: Modest Benefit in PCI

ROME, ITALY — The first randomized trial to investigate the use of optical coherence tomography (OCT) in PCI has suggested that the procedure is safe and may be associated with some benefit[1].

The DOCTORS study was presented today at the European Society of Cardiology (ESC) 2016 Congress and simultaneously published online in Circulation.
The OCT technology visualizes the artery and stent placements, allowing the operator to make alterations on stent expansions and positioning. The intravascular procedure allows improved plaque characterization and can lead to improvements in lesion coverage, stent expansion, or apposition, explained lead investigator Dr Nicolas Meneveau (University Hospital Jean Minjoz, Besançon, France). Downsides of its use include prolonged procedural time and higher exposure to contrast media, as well as the cost issue.
The main result of DOCTORS study showed a modest 2-point improvement in fractional flow reserve (FFR) in NSTEMI patients undergoing PCI guided by OCT compared with those undergoing PCI guided by fluoroscopy alone.
Meneveau said: "This is a small absolute benefit in FFR, but it was statistically significant." Asked whether this would be clinically relevant, he said couldn't comment on that, although it is known that an increase in FFR is associated with a reduction in clinical outcomes. "We obviously need a clinical end-point study to look at clinical benefit," he commented
He added: "But we did show that OCT affected physician decision making, leading to a change in procedural strategy in half of cases, most commonly optimization of stent expansion. The benefit was obtained at the cost of a longer procedure with higher fluoroscopy time and more contrast medium, but without an increase in periprocedural MI or kidney dysfunction."
Meneveau said he also could not comment on whether the benefit shown in this study was worth the additional exposure to contrast media.

"Important Milestone "
In an accompanying editorial in Circulation[2], Dr William Wijns (National University of Ireland, Galway) and Dr Stylianos A Pyxaras (Medizinische Klinik, Coburg, Germany) note that invasive imaging such as OCT or intravascular ultrasound (IVUS) is used extensively in Japan and a little in the US and Asia but is almost nonexistent in Europe. They say that the intracoronary images obtained with these approaches give the physician significant information, but their use is restricted by reimbursement issues, as they have not been shown to affect patient outcomes. They therefore describe the DOCTORS study as an "important milestone" to accumulate global evidence to support the role of OCT guidance during complex PCI and to extend the guidelines supporting its use.

"Safety Encouraging" Senior author of the study, Dr François Schiele (University Hospital Jean Minjoz, Besançon, France), told heartwire from Medscape that he was encouraged by the safety results in the study. "When the DOCTORS study was conceived, I was concerned about possibility of side effects, as this is a very invasive intervention and prolongs the PCI procedure. But we didn't show any harm. The safety side actually looks good. This is valuable information, as OCT is widely used in many centers and we need to know that it is safe." On the benefit, Schiele said: "Although the overall benefit was only two units in FFR, which is a modest amount, it could have an impact. We know that an increase in FFR is linked to reduced outcomes. But for some patients the FFR increase was much higher and would be likely linked to a clinical benefit." He explained that at present OCT is often used before PCI if information is missing on angiography, particularly if it is an important artery such as the left main that is being stented. "But actually we found that it gave us much more useful information after stenting to identify incomplete expansion or malapposition . . . so we can fix those problems."

For the study, 240 NSTEMI patients were randomized to OCT-guided PCI (use of OCT pre- and post-PCI) or to standard fluoroscopy-guided PCI.

Results showed that OCT use led to a change in procedural strategy in 50% of patients. Post-PCI OCT revealed stent underexpansion in 42% of patients, stent malapposition in 32%, incomplete lesion coverage in 20%, and edge dissection in 37.5%. This led to the more frequent use of poststent overdilation in the OCT-guided group vs the angiography-guided group (43% vs 12.5%, P

With thanks to heart.org and European Society of Cardiology (ESC) Congress 2016


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