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 mm²in 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 mm²in OFDI and IVUS group, respectively (P_{non-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.