This document may be broadly used as a standard reference regarding the current state of the IVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVOCT data.

At 6 months, most of the SES were covered with thin neointima, but few showed full coverage.

Objective We evaluated the association between atherosclerotic plaque characteristics (APCs) by coronary CT angiography (CT) and lesion ischemia by fractional flow reserve (FFR). Background FFR is the gold standard for determining lesion ischemia. While APCs by CT—including aggregate plaque volume % (%APV), positive remodeling (PR), low attenuation plaque (LAP) and spotty calcification (SC)—are associated with future coronary syndromes, their relationship to lesion ischemia is unclear. Methods 252 patients (17 centers, 5 countries) [mean age 63 years, 71% males] underwent CT, with FFR performed for 407 coronary lesions. CT was interpreted for < and >50% stenosis, with the latter considered obstructive. APCs by CT were defined as: (1) PR, lesion diameter/reference diameter >1.10; (2) LAP, any voxel <30 HU; and (3) SC, nodular calcified plaque <3 mm. Odds ratios (OR) and net reclassification improvement (NRI) of APCs for lesion ischemia, defined by FFR <0.8, were analyzed. Results By FFR, ischemia was present in 151 lesions (37%). %APV was associated with a 10% increased risk of ischemia per 5% additional APV. PR, LAP and SC were associated with ischemia, with a 3-5 times higher prevalence than in non-ischemic lesions. In multivariable analyses, a stepwise increased risk of ischemia was observed for 1 [OR 4.5, p<0.001)] and ≥2 (OR 13.2, p<0.001) APCs. These findings were APC-dependent, with PR (OR 5.4, p<0.001) and LAP (OR 2.2, p=0.028) associated with ischemia, but not SC. When examined by stenosis severity, PR remained a predictor of ischemia for all lesions, while %APV and LAP were associated with ischemia for only >50% but not for <50% stenosis. Conclusions %APV and APCs by CT improve identification of coronary lesions that cause ischemia. PR is associated with all ischemia-causing lesions, while %APV and LAP are only associated with ischemia-causing lesions >50%.

In 56 patients with angina, 126 plaques identified by IVUS findings were analysed using both VH-IVUS and OCT. IVUS-derived TCFA was defined as an abundant necrotic core (>10% of the cross-sectional area) in contact with the lumen (NCCL) and %plaque-volume >40%. OCT-derived TCFA was defined as a fibrous cap thickness of <65 microm overlying a low-intensity area with an unclear border. Plaque meeting both TCFA criteria was defined as definite-TCFA. Sixty-one plaques were diagnosed as IVUS-derived TCFA and 36 plaques as OCT-derived TCFA. Twenty-eight plaques were diagnosed as definite-TCFA; the remaining 33 IVUS-derived TCFA had a non-thin-cap and eight OCT-derived TCFA had a non-NCCL (in discord with NCCL visualized by VH-IVUS, mainly due to misreading caused by dense calcium). Based on IVUS findings, definite-TCFA showed a larger plaque and vessel volume, %plaque-volume, higher vessel remodelling index, and greater angle occupied by the NCCL in the lumen circumference than non-thin-cap IVUS-derived TCFA. Conclusion Neither modality alone is sufficient for detecting TCFA. The combined use of OCT and VH-IVUS might be a feasible approach for evaluating TCFA.

AimsOptical frequency domain imaging (OFDI) is a recently developed, light-based, high-resolution intravascular imaging technique. Intravascular ultrasound (IVUS) is a widely used, conventional imaging technique for guiding percutaneous coronary intervention (PCI). We aimed to demonstrate the non-inferiority of OFDI-guided PCI compared with IVUS-guided PCI in terms of clinical outcomes.Methods and resultsWe did a prospective, multicentre, randomized (ratio 1:1), active-controlled, non-inferiority study to compare head-to-head OFDI vs. IVUS in patients undergoing PCI with a second generation drug-eluting stent. The primary endpoint was target vessel failure defined as a composite of cardiac death, target-vessel related myocardial infarction, and ischaemia-driven target vessel revascularization until 12 months after the PCI. The major secondary endpoint was angiographic binary restenosis at 8 months. We randomly allocated 829 patients to receive OFDI-guided PCI (n = 414) or IVUS-guided PCI (n = 415). Target vessel failure occurred in 21 (5.2%) of 401 patients undergoing OFDI-guided PCI, and 19 (4.9%) of 390 patients undergoing IVUS-guided PCI, demonstrating non-inferiority of OFDI-guided PCI to IVUS-guided PCI (hazard ratio 1.07, upper limit of one-sided 95% confidence interval 1.80; Pnon-inferiority = 0.042). With 89.8% angiographic follow-up, the rate of binary restenosis was comparable between OFDI-guided PCI and IVUS-guided PCI (in-stent: 1.6% vs. 1.6%, P = 1.00; and in-segment: 6.2% vs. 6.0%, P = 1.00).ConclusionThe 12-month clinical outcome in patients undergoing OFDI-guided PCI was non-inferior to that of patients undergoing IVUS-guided PCI. Both OFDI-guided and IVUS-guided PCI yielded excellent angiographic and clinical results, with very low rates of 8-month angiographic binary restenosis and 12-month target vessel failure.Clinical registrationClinicalTrials.gov, number NCT01873027.