May 14, 2020
OCT Imaging Studied to Predict FFR Values in Coronary Lesions
May 14, 2020—The Society for Cardiovascular Angiography and Interventions (SCAI) announced findings from a study that sought to evaluate whether optical coherence tomography (OCT) parameters may predict fractional flow reserve (FFR) values and assess if OCT parameters may predict clinical outcome in patients with negative FFR. The study was presented as late-breaking science at the SCAI 2020 Scientific Sessions Virtual Conference held May 14–16, 2020.
“The idea of predicting hemodynamic relevance of coronary lesions from imaging is extremely appealing,” commented Rocco Vergallo, MD, in the SCAI press release. “In this collaborative study, we sought to investigate if OCT parameters may help predict the presence of hemodynamically significant stenoses among angiographically intermediate coronary lesions. We put together data collected from different studies so that we have been able to analyze individual data of about 500 patients."
Led by Francesco Burzotta, MD, the investigators designed a multicenter international study using individual patient-level data pooled analysis. They enrolled stable or unstable patients who underwent both FFR and OCT of the same coronary lesion.
The primary outcome measures were OCT parameters predicting an FFR < 0.8, including mean lumen area (MLA), percentage area stenosis (%AS), and presence of plaque thrombus/rupture. The secondary outcome was the incidence of major adverse cardiac event (MACE) in patients not undergoing revascularization based on negative FFR (≥ 0.8). MACE was defined as the composite of cardiac death, spontaneous myocardial infarction, and target lesion revascularization.
As summarized in the SCAI announcement, the study included 502 coronary lesions in 489 patients. The investigators found the following:
- A significant correlation was observed between OCT MLA and FFR values (R = 0.525; P < .001) and between OCT %AS and FFR values (R = –0.482; P < .001); plaque thrombus/rupture did not differ significantly.
- At receiver-operator characteristic analysis, an OCT MLA < 2 mm2 showed a good discriminative power to predict an FFR < 0.8 (area under the curve [AUC], 0.8), as well as an OCT %AS > 73% (AUC, 0.73).
- When considering proximal coronary segments only, the best OCT cutoff values predicting an FFR < 0.8 were MLA < 3.1 mm2 (AUC, 0.82) and %AS > 61% (AUC, 0.84).
Additionally, the investigators reported that among 105 patients who had not undergone revascularization based on negative FFR and had completed the clinical follow-up, 11 (10.5%) had MACE. Median follow-up time was 6 years (interquartile range, 2.3-8.3). Patients with MLA < 2 mm2 showed a nonsignificantly higher incidence of MACE than those with MLA ≥ 2 mm2 (16.7% vs 9.2%; P = .139).
Dr. Vergallo concluded, “These findings are important because they may allow interventional cardiologists to gather both data on plaque morphology/lumen dimension and indirect information on the functional significance of a stenosis by using an imaging catheter only, without the need for an additional pressure wire. This would, in turn, reduce both patient risk and health care expenses.”