Eric A. Osborn

Introduction: Provocative coronary vasospasm testing requires intracoronary acetylcholine (ACh) administration, however an ACh drug formulation approved for intracoronary use is not commercially available. Invasive coronary vasomotor testing programs have thus resorted to reconstituting and diluting ophthalmic ACh solutions for off-label and off-target intracoronary use, despite a lack of comprehensive ACh stability testing data required by pharmacy compounding regulations USP . This study aims to characterize the stability of compounded ACh intraocular solutions according to current pharmacy guidelines for use in provocative intracoronary ACh vasospasm testing. Methods: Potency and stability testing was performed by an FDA and DEAS registered, A2LA ISO 17025:2017 accredited laboratory. Using a simple, 7-step compounding method, a single vial of intraocular ACh solution was reconstituted and diluted with 500 mL of dextrose 5% water (D5W) to a final concentration of 18.2 mcg/mL. Compounded ACh was then stored in 20 mL syringes at ambient room temperature (25 ± 2 °C and 60 ± 5% relative humidity) under normal fluorescent lighting to simulate routine cardiac catheterization laboratory conditions. The compounded ACh solution appearance, pH, particulate matter, concentration and potency were evaluated in triplicate at 0, 4, and 12 h after compounding. Results: The compounded ACh solution was clear and colorless with a pH of 4.2 across all time points. Subvisible particulate matter, assessed by light obscuration techniques, demonstrated that the quantity of >10 μ m and >25 μ m particles present in each syringe remained safely within USP specifications. Finally, using high-performance liquid chromatography – mass spectrometry, the compounded ACh solutions revealed no significant degradation during the studied time frame, with 96.7 ± 0.3% of the initial ACh retained at 12 h, satisfying USP regulations to maintain 90.0% - 110.0% of label claim (18.2 mcg/mL). Conclusion: Utilizing a novel compounding method, intraocular ACh reconstituted and diluted in D5W met all USP pharmacy stability regulatory criteria over 12 h under ambient room temperature storage conditions. This study thus establishes a simplified ACh compounding approach for invasive coronary function testing centers to generate an intracoronary ACh drug formulation for use within 12 h in provocative coronary vasospasm testing procedures.

Background/Aims: Intravascular imaging during percutaneous coronary intervention (PCI) improves clinical outcomes; however, is dependent on accurate and rapid interpretation of the images generated. This study aimed to compare coronary artery calcification assessment using a novel automated artificial intelligence (AI) software algorithm with manual optical coherence tomography (OCT) image analysis. Methods and Results: A deep neural network based on a UNet-like architecture was developed and trained to identify calcified atherosclerotic plaque from an independent dataset of expert-annotated clinical intravascular OCT pullbacks. The AI network was subsequently validated on previously unseen clinical OCT pullbacks that were manually annotated for plaque calcium and used to quantify clinically relevant calcified plaque characteristics. Correlation and agreement between the expert-annotated images and the model predictions were evaluated. In total, 8259 cross-sectional images comprised the training and internal validation dataset. Pixel-based classification by the AI model performed best to identify calcified plaque (AUC = 0.96), with an overall diagnostic accuracy of 73.3%. During independent external validation, the model correctly identified 934 of the 1248 calcified plaques, corresponding to a diagnostic accuracy of 74.8%. The AI model performed well in assessing the calculated OCT-calcium score (ρ = 0.84; 95% confidence interval [CI], 0.81–0.87, p ≤ 0.001). Conclusions: Implementation of an automated AI software algorithm provides a rapid and efficient method to comprehensively map coronary calcium in intravascular OCT images. With further training and refinement, it is anticipated that the AI machine learning software will continue to improve, enabling new robust tools for clinical OCT calcium detection to better guide PCI procedures.

Calcific aortic valve disease (CAVD) is the most common valve disease, which consists of a chronic interplay of inflammation, fibrosis, and calcification. In this study, sortilin (SORT1) was identified as a novel key player in the pathophysiology of CAVD, and its role in the transformation of valvular interstitial cells (VICs) into pathological phenotypes is explored. An aortic valve (AV) wire injury (AVWI) mouse model with sortilin deficiency was used to determine the effects of sortilin on AV stenosis, fibrosis, and calcification. In vitro experiments employed human primary VICs cultured in osteogenic conditions for 7, 14, and 21 days; and processed for imaging, proteomics, and transcriptomics including single-cell RNA-sequencing (scRNA-seq). The AVWI mouse model showed reduced AV fibrosis, calcification, and stenosis in sortilin-deficient mice vs. littermate controls. Protein studies identified the transition of human VICs into a myofibroblast-like phenotype mediated by sortilin. Sortilin loss-of-function decreased in vitro VIC calcification. ScRNA-seq identified 12 differentially expressed cell clusters in human VIC samples, where a novel combined inflammatory myofibroblastic-osteogenic VIC (IMO-VIC) phenotype was detected with increased expression of SORT1, COL1A1, WNT5A, IL-6, and serum amyloid A1. VICs sequenced with sortilin deficiency showed decreased IMO-VIC phenotype. Sortilin promotes CAVD by mediating valvular fibrosis and calcification, and a newly identified phenotype (IMO-VIC). This is the first study to examine the role of sortilin in valvular calcification and it may render it a therapeutic target to inhibit IMO-VIC emergence by simultaneously reducing inflammation, fibrosis, and calcification, the three key pathological processes underlying CAVD. Multi-omic approach to identify the role of sortilin in mediating fibrosis and calcification in calcific aortic valve disease (CAVD). Aortic valve (AV) wire injury in sortilin wild-type (Sort1^+/+) and deficient mice (Sort1^−/−) showed decreased collagen deposition and calcification in mouse AVs. Valvular interstitial cells (VICs) were collected from human CAVD tissue and cultured in osteogenic conditions. VICs collected at varying time points of culture (Days 7, 14, and 21) were processed for flow cytometry, proteomics, and single-cell RNA-sequencing (scRNA-seq). Multiomics data identified increased sortilin expression following the osteogenic culture of VICs. Protein analysis and scRNA-seq identified increased expression of WNT5a, MAPK, YAP, and IL-6 regulated by the expression of sortilin. ScRNA-seq identified a transitionary VIC subpopulation with an activated myofibroblast phenotype that later transitioned into a combined myofibroblast and osteogenic phenotype. ScRNA-seq data identified an inflammatory myofibroblastic-osteogenic VIC (IMO-VIC) subpopulation that may be a key player in the pathogenesis of CAVD under the regulation of sortilin.

BACKGROUND: New pharmacological approaches are needed to prevent stent restenosis. This study tested the hypothesis that pemafibrate, a novel clinical selective PPARα (peroxisome proliferator‐activated receptor α) agonist, suppresses coronary stent‐induced arterial inflammation and neointimal hyperplasia. METHODS AND RESULTS: Yorkshire pigs randomly received either oral pemafibrate (30 mg/day; n=6) or control vehicle (n=7) for 7 days, followed by coronary arterial implantation of 3.5 × 12 mm bare metal stents (2–4 per animal; 44 stents total). On day 7, intracoronary molecular‐structural near‐infrared fluorescence and optical coherence tomography imaging was performed to assess the arterial inflammatory response, demonstrating that pemafibrate reduced stent‐induced inflammatory protease activity (near‐infrared fluorescence target‐to‐background ratio: pemafibrate, median [25th‐75th percentile]: 2.8 [2.5–3.3] versus control, 4.1 [3.3–4.3], P =0.02). At day 28, animals underwent repeat near‐infrared fluorescence–optical coherence tomography imaging and were euthanized, and coronary stent tissue molecular and histological analyses. Day 28 optical coherence tomography imaging showed that pemafibrate significantly reduced stent neointima volume (pemafibrate, 43.1 [33.7–54.1] mm ³ versus control, 54.2 [41.2–81.1] mm ³ ; P =0.03). In addition, pemafibrate suppressed day 28 stent‐induced cellular inflammation and neointima expression of the inflammatory mediators TNF‐α (tumor necrosis factor‐α) and MMP‐9 (matrix metalloproteinase 9) and enhanced the smooth muscle differentiation markers calponin and smoothelin. In vitro assays indicated that the STAT3 (signal transducer and activator of transcription 3)–myocardin axes mediated the inhibitory effects of pemafibrate on smooth muscle cell proliferation. CONCLUSIONS: Pemafibrate reduces preclinical coronary stent inflammation and neointimal hyperplasia following bare metal stent deployment. These results motivate further trials evaluating pemafibrate as a new strategy to prevent clinical stent restenosis.

Purpose of review Physiological assessment of coronary artery disease (CAD) is an essential component of the interventional cardiology toolbox. However, despite long-term data demonstrating improved outcomes, physiology-guided percutaneous coronary intervention (PCI) remains underutilized in current practice. This review outlines the indications and technical aspects involved in evaluating coronary stenosis physiology, focusing on the latest developments in the field. Recent findings Beyond fractional flow reserve (FFR), non-hyperemic pressure ratios (NHPR) that assess coronary physiology at rest without hyperemia now abound. Additional advances in other alternative FFR approaches, including non-invasive coronary CT (FFR_CT), invasive angiography (FFR_angio), and optical coherence tomography (FFR_OCT), are being realized. Artificial intelligence algorithms and robust tools that enable detailed pre-procedure “virtual” intervention are also emerging. Summary The benefits of coronary physiological assessment to determine lesion functional significance are well established. In addition to stable CAD, coronary physiology can be especially helpful in clinical scenarios such as left main and multivessel CAD, serial lesions, non-infarct-related arteries in acute coronary syndromes, and residual ischemia post-PCI. Today, coronary physiological assessment remains an indispensable tool in the catheterization laboratory, with an exciting technological future that will further refine clinical practice and improve patient care.