An invasive imaging technique called optical coherence tomography (OCT) can visualize the coronary arteries in patients undergoing percutaneous coronary intervention (PCI) and lead to better outcomes compared to standard angiography-guided PCI, according to new findings reported here.
Results of the DOCTORS (Does Optical Coherence Tomography Optimize Results of Stenting) study were presented in a Hot Line session at ESC Congress 2016, with simultaneous publication in Circulation.
In patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS), OCT "provided useful additional information beyond that obtained by angiography alone, and impacted directly on physician decision-making," reported the study's lead investigator Nicolas Meneveau, MD, PhD, from University Hospital Jean Minjoz, in Besançon, France.
OCT, which involves introducing an imaging catheter into the coronary artery to check vessel size, lesion characteristics, and stent positioning and expansion "led to a change in procedural strategy in half of cases," said Prof. Meneveau.
However, "additional prospective randomized studies with clinical endpoints are required before it can be recommended for standard use."
The multi-centre trial included 240 NSTE-ACS patients who were randomised 1:1 to standard fluoroscopy-guided PCI alone (angio group) or with the addition of OCT - performed an average of 3.8 times, before, during and after the procedure.
Overall, OCT was associated with better functional outcome than PCI guided by fluoroscopy alone, said Prof Meneveau.
The primary endpoint of the study, which was fractional flow reserve (FFR) - a measure of blood flow and pressure in the coronary artery before and after the procedure - was significantly better in the OCT group as compared to the angio group (0.94 vs 0.92, p=0.005).
In addition, the number of patients with a post-procedural FFR>0.90 was significantly higher in the OCT group (82.5% vs 64.2%, p=0.0001).
Compared to angiography, OCT allowed clinicians to see significantly more thrombi (69% vs 47%, p=0.0004) and calcifications (45.8% vs 9%, p<0.0001) before stent implantation. This resulted in more frequent antiplatelet use in the OCT group (53.3% vs. 35.8%).
As well, OCT was also significantly more likely to reveal stent underexpansion (42% vs 10.8%), incomplete lesion coverage (20% vs 17%, and edge dissection (37.5% vs 4%), compared to angio.
Stent malapposition, which is not visible under fluoroscopy alone, was observed in 32% of patients undergoing OCT.
These observations led to the more frequent use of post-stent overinflation in the OCT group (43% vs. 12.5%, p<0.0001) and a lower percentage of residual stenosis (7.0% vs 8.7%, p=0.01).
The addition of OCT increased procedure time as well patients' exposure to fluoroscopy and contrast medium, but this did not increase complications such as peri-procedural myocardial infarction or impaired kidney function, added Prof. Meneveau.
"Findings of the DOCTORS study add to the cumulating body of evidence in favor of a potential benefit of OCT to guide angioplasty," he said. "The improvement in functional outcomes could translate into a clinical benefit in the longer term."
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