Comparison Between Optical Frequency Domain Imaging and Intravascular Ultrasound for Percutaneous Coronary Intervention Guidance in Biolimus A9-Eluting Stent Implantation: A Randomized MISTIC-1 Non-Inferiority Trial.

BACKGROUND: Given the characteristic differences between intravascular ultrasound (IVUS) and optical frequency domain imaging (OFDI), their approach to therapeutic guidance during percutaneous coronary interventions (PCIs) and arterial healing response after stenting may also vary. METHODS: MISTIC-1 (The Multimodality Imaging Study in Cardiology cohort 1) is a multicenter, randomized-controlled, noninferiority trial that compared imaging end points between OFDI- and IVUS-guided PCI. Patients with stable coronary artery disease were randomly assigned to either OFDI- or IVUS-guided PCI using a Biolimus A9-eluting stent according to a prespecified protocol for imaging guidance. Stent sizing was based on external elastic lamina in IVUS-guided PCI while lumen up-size in OFDI-guided PCI. Postprocedural OFDI was investigated regardless of randomization, while operators in IVUS-guided PCI arm were blinded to the images. The primary end point was in-segment minimum lumen area assessed using OFDI at 8 months, while the secondary end point was a composite of cardiovascular mortality, target-vessel myocardial infarction, or target-lesion revascularization (device-oriented composite end point). Patients were followed up to 3 years after the index procedure. RESULTS: A total of 109 patients (mean age 70 years, male 78%) with 126 lesions were enrolled. Postprocedural minimum stent area was 6.31±1.89 and 6.72±2.08 mm2 in OFDI and IVUS group, respectively (P=0.26). At the 8-month follow-up, in-segment minimum lumen area was 4.56±1.94 and 4.13±1.86 mm2 in OFDI and IVUS group, respectively (Pnon-inferiority <0.001). Both groups had comparable neointimal healing score (median 0.16 [interquartile range, 0.00-3.14] versus 0.90 [0.00-3.30], respectively; P=0.43). The incidence rate of device-oriented composite end point at 3 years was 7.4% and 7.3% in OFDI and IVUS group, respectively (hazard ratio, 1.05 [95% CI, 0.26-4.18]; P=0.95). CONCLUSIONS: OFDI-guided PCI was not inferior to IVUS-guided PCI in terms of in-segment minimum lumen area at 8 months. Although a small sample size was acknowledged, OFDI could be an alternative to IVUS when considering intracoronary imaging-guided PCI in selected populations with coronary artery diseases. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03292081.

Associations of coronary plaque characteristics by integrated backscatter intravascular ultrasound with detectability of vessel external elastic lamina using optical frequency domain imaging in human coronary arteries: A sub-analysis of the MISTIC-1 trial.

OBJECTIVES: We sought to examine associations between plaque characteristics by intravascular ultrasound (IVUS) and detectability of external elastic lamina (EEL) by optical frequency domain imaging (OFDI) in human coronary arteries. BACKGROUND: It is often challenging to detect EEL which represents vessel size by light-based imaging modalities due to light intensity attenuation through atherosclerotic plaque. METHODS: IVUS and OFDI prior to stent implantation were sequentially investigated per protocol. We identified corresponding cross-sections by minimum lumen area (MLA) or just distally to side branches as anatomical landmarks. Plaque characterization was determined by integrated backscatter IVUS analysis. We categorized detectable EEL arc by OFDI into four groups: 0≤ and <1 quadrant (group 1), 1≤ and <2 quadrants (group 2), 2≤ and <3 quadrants (group 3), or 3≤ and <4 quadrants (group 4). RESULTS: We prospectively studied 103 vessels in 93 patients with stable coronary artery disease. Corresponding 711 cross-sections were analyzed. Cross-sections with detectable EEL arc <2 quadrants (group 1 or 2) were observed in 86.1% of MLA sites but only in 29.3% of non-MLA sites (p < .05). Percentage plaque area (%PA) appeared to be the strongest predictor to detect EEL arc <2 quadrants with the cut-off of 60.3% (AUC 0.90; sensitivity 79.8%, specificity 85.5%). Lipid pool and calcification remained statistically significant in predicting detectable EEL arc <2 quadrants after adjustment with %PA. CONCLUSIONS: Presence of large plaque burden, lipid pool, and calcification significantly predicts the detectability of EEL by OFDI assessment. Locations with detectable EEL arc <2 quadrants should thus be avoided for optimal stent landing zone.