Novel OCT-based FFR Technique Saves a Step in PCI

Neil Osterweil

June 06, 2019

PARIS — A novel hybrid coronary artery imaging method employing an optical coherence tomography (OCT)-based fractional flow reserve (FFR) computational approach provides both lesion morphology and physiological assessment in a single OCT image pullback, resulting in potential savings in both time and the use of disposable instruments normally required for separate OCT and FFR measures.

The OCT-based FFR system, abbreviated as OFR, showed good diagnostic accuracy and reproducibility with a short analysis time, and offered "substantially better" diagnostic accuracy than OCT measurement of minimal lumen area (OCT-MLA), reported Shengxian Tu, ND, from Shanghai Jiao Tong University.

"OFR is promising for use in the cath lab for PCI optimization," he said at a briefing prior to his presentation of the data here at the Congress of the European Association of Percutaneous Cardiovascular Interventions 2019.

The study was also published online May 23, to coincide with Tu's presentation, in EuroIntervention .

Tu and colleagues conducted a retrospective, multicenter, observational study to evaluate the diagnostic accuracy of OFR using wire-guided FFR as the reference standard.

They performed a post hoc analysis looking at patients who had least one vessel imaged by both OCT and FFR prior to intervention, using data provided by University Hospitals Cleveland Medical Center, Nanjing First Hospital in China, and Prince Charles Hospital in Queensland, Australia.

The investigators used proprietary software (OctPlus, Pulse Medical Imaging Technology, Shanghai) to analyze OFR and compare it with FFR, both using a cut-off value of 0.80 to define ischemia.

They compared OFR with FFR in 128 vessels with 168 OCT pullbacks, 125 of which had been performed before PCI and 43 after PCI. An additional 51 OCT pullbacks were excluded because of vessel spasm or injury, OCT not covering the entire lesion, substantial thrombosis identified by OCT, or suboptimal OCT image quality.

OFR results correlated positively and strongly with FFR (r = 0.84; < .001), with a mean difference between the two of 0.01.

The accuracy of OFR to identify FFR of 0.80 or less was 90%, with 87% sensitivity, 92% specificity, 92% positive-predictive value, and 88% negative-predictive value.

In contrast, the respective accuracy, sensitivity, specificity, PPV, and NPV with OCT-MLA were 74%, 78%, 71%, 73%, and 76%.

The area under the curve (AUC) of receiver operating characteristics was higher for OFR than with OCT-MLA (0.93 vs 0.80; = .002).

The average OFR analysis time for each pullback was 55 ± 23 seconds.

Combining Techniques

"What this is really doing is combining two separate techniques into one," commented Nicolo Piazza, MD, McGill University, Montreal, who comoderated the briefing in which Tu presented the data.

"What the physicians are trying to do is create one test where you can get not only the structure and anatomic characteristics of the vessel, but also the hemodynamic significance of the vessel and structure. Usually we have to do two separate procedures for this," he said.

"I think the integration of FFR with OCT is very intriguing," commented Stephan Windecker, MD, Bern Univeristy Hospital, Switzerland, who also comoderated the briefing.

"Basically, it saves you one step, so I'm looking forward to more validation and more data related to this," he told | Mescape Cardiology.

The study was supported by Pulse Medical Imaging Technology. Tu disclosed receipt of grants from the company. Piazza and Windecker reported no relevant conflicts of interest.

Congress of the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) 2019. Presented May 23, 2019.

EuroIntervention. Published online May 23, 2019. Abstract


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