Data regarding clinical outcomes after optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) as compared with angiography-guided PCI are limited. In this prospective, randomized, single-blind trial, we randomly assigned patients with medication-treated diabetes or complex coronary-artery lesions to undergo OCT-guided PCI or angiography-guided PCI. A final blinded OCT procedure was performed in patients in the angiography group. The two primary efficacy end points were the minimum stent area after PCI as assessed with OCT and target-vessel failure at 2 years, defined as a composite of death from cardiac causes, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization. Safety was also assessed. The trial was conducted at 80 sites in 18 countries. A total of 2487 patients underwent randomization: 1233 patients were assigned to undergo OCT-guided PCI, and 1254 to undergo angiography-guided PCI. The minimum stent area after PCI was 5.72±2.04 mm² in the OCT group and 5.36±1.87 mm² in the angiography group (mean difference, 0.36 mm²; 95% confidence interval [CI], 0.21 to 0.51; P<0.001). Target-vessel failure within 2 years occurred in 88 patients in the OCT group and in 99 patients in the angiography group (Kaplan-Meier estimates, 7.4% and 8.2%, respectively; hazard ratio, 0.90; 95% CI, 0.67 to 1.19; P = 0.45). OCT-related adverse events occurred in 1 patient in the OCT group and in 2 patients in the angiography group. Stent thrombosis within 2 years occurred in 6 patients (0.5%) in the OCT group and in 17 patients (1.4%) in the angiography group. Among patients undergoing PCI, OCT guidance resulted in a larger minimum stent area than angiography guidance, but there was no apparent between-group difference in the percentage of patients with target-vessel failure at 2 years. (Funded by Abbott; ILUMIEN IV: OPTIMAL PCI ClinicalTrials.gov number, NCT03507777.).

Over the past 2 decades, chronic total occlusion (CTO) percutaneous coronary intervention has developed into its own subspecialty of interventional cardiology. Dedicated terminology, techniques, devices, courses, and training programs have enabled progressive advancements. However, only a few randomized trials have been performed to evaluate the safety and efficacy of CTO percutaneous coronary intervention. Moreover, several published observational studies have shown conflicting data. Part of the paucity of clinical data stems from the fact that prior studies have been suboptimally designed and performed. The absence of standardized end points and the discrepancy in definitions also prevent consistency and uniform interpretability of reported results in CTO intervention. To standardize the field, we therefore assembled a broad consortium comprising academicians, practicing physicians, researchers, medical society representatives, and regulators (US Food and Drug Administration) to develop methods, end points, biomarkers, parameters, data, materials, processes, procedures, evaluations, tools, and techniques for CTO interventions. This article summarizes the effort and is organized into 3 sections: key elements and procedural definitions, end point definitions, and clinical trial design principles. The Chronic Total Occlusion Academic Research Consortium is a first step toward improved comparability and interpretability of study results, supplying an increasingly growing body of CTO percutaneous coronary intervention evidence.

Background: Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs in 6% to 15% of myocardial infarctions (MIs) and disproportionately affects women. Scientific statements recommend multimodality imaging in MINOCA to define the underlying cause. We performed coronary optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) imaging to assess mechanisms of MINOCA. Methods: In this prospective, multicenter, international, observational study, we enrolled women with a clinical diagnosis of myocardial infarction. If invasive coronary angiography revealed <50% stenosis in all major arteries, multivessel OCT was performed, followed by CMR (cine imaging, late gadolinium enhancement, and T2-weighted imaging and T1 mapping). Angiography, OCT, and CMR were evaluated at blinded, independent core laboratories. Culprit lesions identified by OCT were classified as definite or possible. The CMR core laboratory identified ischemia-related and nonischemic myocardial injury. Imaging results were combined to determine the mechanism of MINOCA, when possible. Results: Among 301 women enrolled at 16 sites, 170 were diagnosed with MINOCA, of whom 145 had adequate OCT image quality for analysis; 116 of these underwent CMR. A definite or possible culprit lesion was identified by OCT in 46.2% (67/145) of participants, most commonly plaque rupture, intraplaque cavity, or layered plaque. CMR was abnormal in 74.1% (86/116) of participants. An ischemic pattern of CMR abnormalities (infarction or myocardial edema in a coronary territory) was present in 53.4% (62/116) of participants undergoing CMR. A nonischemic pattern of CMR abnormalities (myocarditis, takotsubo syndrome, or nonischemic cardiomyopathy) was present in 20.7% (24/116). A cause of MINOCA was identified in 84.5% (98/116) of the women with multimodality imaging, higher than with OCT alone ( P <0.001) or CMR alone ( P =0.001). An ischemic cause was identified in 63.8% of women with MINOCA (74/116), a nonischemic cause was identified in 20.7% (24/116) of the women, and no mechanism was identified in 15.5% (18/116). Conclusions: Multimodality imaging with coronary OCT and CMR identified potential mechanisms in 84.5% of women with a diagnosis of MINOCA, 75.5% of which were ischemic and 24.5% of which were nonischemic, alternate diagnoses to myocardial infarction. Identification of the cause of MINOCA is feasible and has the potential to guide medical therapy for secondary prevention. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02905357.

Background: Coronary calcification inhibits stent expansion. We sought to establish an intravascular ultrasound–derived calcium score to predict stent underexpansion. Methods: This is a retrospective observational study including de novo lesions that underwent intravascular ultrasound–guided stenting and had maximum superficial calcium angle >270°. Lesions with angiographic calcium not treated with atherectomy or scoring/cutting balloon before stent implantation were randomly divided into derivation and validation cohorts. The end point was stent expansion (minimum stent area/average of reference lumen area) at the maximum calcium site, and stent expansion 270° longer than 5 mm (regression coefficient, −13.0 [95% CI, −18.1 to −7.8], P <0.0001), (2) 360° of superficial calcium (regression coefficient, −14.2 [95% CI, −22.8 to −5.5], P =0.001), (3) calcified nodule (regression coefficient, −8.3 [95% CI, −14.3 to −2.2], P =0.007), and (4) vessel diameter <3.5 mm (regression coefficient, −9.4 [95% CI, −16.0 to −2.7], P =0.006). The calcium score (0-4) was significantly correlated with poor stent expansion (regression coefficient, −8.1 [95% CI, −10.5 to −5.7], P <0.0001) in the validation cohort as well as in the atherectomy cohort (regression coefficient, −4.8 [95% CI, −7.2 to −2.5], P <0.0001) with significant interaction between validation and atherectomy cohorts ( P _interaction =0.02). In lesions without angiographic calcium, all calcium severity parameters were less than in the validation cohort, and stent underexpansion was observed in only 1.5% (1/67) of lesions. Conclusions: This intravascular ultrasound calcium score provides the interventionalists with a reliable tool to identify calcified stenoses at risk for stent underexpansion and requiring adjunctive calcium modification before stent implantation.

The feasibility, safety, and clinical utility of percutaneous coronary intervention (PCI) without radio-contrast medium in patients with advanced chronic kidney disease (CKD) are unknown. In this series, we investigated a specific strategy for ‘zero contrast’ PCI with the aims of preserving renal function and preventing the need for renal replacement therapy (RRT) in patients with advanced CKD. A total of 31 patients with advanced CKD [creatinine = 4.2 mg/dL, inter-quartile range (IQR) 3.1–4.8, estimated glomerular filtration rate = 16 ± 8 mL/min/1.73 m²] who had clinical indication for PCI based on a prior minimal contrast coronary angiogram were included. Zero contrast PCI was performed at least 1 week after diagnostic angiography using real-time intravascular ultrasound (IVUS) guidance, with pre- and post-PCI measurements of fractional flow reserve and coronary flow reserve to confirm physiological improvement. This approach resulted in successful PCI, no major adverse cardiovascular events and preservation of renal function without the need for RRT within a follow-up time of 79 days (IQR 33–207) in all patients. In patients with advanced CKD who require revascularization, PCI may safely be performed without contrast using IVUS and physiological guidance with high procedural success and without complications.