No abstract

An OCT-based calcium scoring system can help to identify lesions that would benefit from plaque modification prior to stent implantation. Lesions with calcium deposit with maximum angle >180°, maximum thickness >0.5 mm, and length >5 mm may be at risk of stent underexpansion.

Procedural guidance with intravascular ultrasound (IVUS) imaging improves the clinical outcomes of patients undergoing percutaneous coronary intervention (PCI) by: 1) informing the necessity for lesion preparation; 2) directing appropriate stent sizing to maximize the final stent area and minimize geographic miss; 3) selecting the optimal stent length to cover residual disease adjacent to the lesion, thus minimizing geographic miss; 4) guiding optimal stent expansion; 5) identifying acute complications (edge dissection, stent malapposition, tissue protrusion); and 6) clarifying the mechanism of late stent failure (stent thrombosis, neointimal hyperplasia, stent underexpansion or fracture, or neoatherosclerosis). Optical coherence tomography (OCT) provides similar information to IVUS (with some important differences), also potentially improving acute and long-term patient outcomes compared to angiography-guided PCI. The purpose of this review is to describe the similarities and differences between IVUS and OCT technologies, and to highlight the evidence supporting their utility to improve PCI outcomes.

Background: Myocardial infarction with non-obstructive coronary arteries (MINOCA) occurs in 6-15% of MI and disproportionately affects women. Scientific statements recommend multi-modality imaging in MINOCA to define the underlying cause. We performed coronary optical coherence tomography (OCT) and cardiac magnetic resonance imaging (CMR) to assess mechanisms of MINOCA. Methods: In this prospective, multicenter, international, observational study, we enrolled women with a clinical diagnosis of MI. If invasive coronary angiography revealed <50% stenosis in all major arteries, multi-vessel OCT was performed, followed by CMR (cine imaging, late gadolinium enhancement, and T2-weighted imaging and/or 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 non-ischemic 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, intra-plaque 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% of participants undergoing CMR (62/116). A non-ischemic pattern of CMR abnormalities (myocarditis, takotsubo syndrome or non-ischemic cardiomyopathy) was present in 20.7% (24/116). A cause of MINOCA was identified in 84.5% of the women with multi-modality imaging (98/116), higher than with OCT alone (p<0.001) or CMR alone (p=0.001). An ischemic etiology was identified in 63.8% of women with MINOCA (74/116), a non-ischemic etiology was identified in 20.7% (24/116), and no mechanism was identified in 15.5% (18/116). Conclusions: Multi-modality imaging with coronary OCT and CMR identified potential mechanisms in 84.5% of women with a diagnosis of MINOCA, three-quarters of which were ischemic and one-quarter of which were non-ischemic, alternate diagnoses to MI. Identification of the etiology of MINOCA is feasible and has the potential to guide medical therapy for secondary prevention. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT02905357

High-resolution imaging by OCT delineated calcium modification with fracture as a major mechanism of action of lithoplasty in vivo and demonstrated efficacy in the achievement of significant acute area gain and favorable stent expansion.