Implicancias de la inteligencia artificial en los métodos de imagen endovascular / Implications of Artificial Intelligence in Intravascular Imaging Methods

RESUMEN La angioplastia transluminal coronaria (ATC) es una de las principales estrategias de revascularización en pacientes con enfermedad coronaria aterosclerótica (ECA). Numerosos estudios respaldan la optimización de la ATC mediante métodos de imagen endovascular; sin embargo, estos métodos son subutilizados en la práctica clínica contemporánea y enfrentan desafíos en la interpretación de los datos obtenidos, por lo que la integración de la inteligencia artificial (IA) se vislumbra como una solución atractiva para promover y simplificar su uso. La IA se define como un programa computarizado que imita la capacidad del cerebro humano para recopilar y procesar datos. El aprendizaje de máquinas es una subdisciplina de la IA que implica la creación de algoritmos capaces de analizar grandes conjuntos de datos sin suposiciones previas, mientras que el aprendizaje profundo se centra en la construcción y entrenamiento de redes neuronales artificiales profundas y complejas. Así, se ha demostrado que la incorporación de sistemas de IA a los métodos de imagen endovascular incrementa la precisión de la ATC, disminuye el tiempo del procedimiento y la variabilidad interobservador en la interpretación de los datos obtenidos, promueve así una mayor adopción y facilita su utilización. El propósito de la presente revisión es destacar cómo los sistemas actuales basados en IA pueden desempeñar un papel fundamental en la interpretación de los datos generados por los métodos de imagen endovascular, lo que conduce a una mejora en la optimización de la ATC en pacientes con ECA.

ABSTRACT Percutaneous coronary intervention (PCI) is one of the primary revascularization strategies in patients with coronary artery disease (CAD). Several studies support the use of intravascular imaging methods to optimize PCI. However, these methods are underutilized in contemporary clinical practice and face challenges in data interpretation. Therefore, the incorporation of artificial intelligence (AI) is seen as an attractive solution to promote and simplify their use. AI can be defined as a computer program that mimics the human brain in its ability to collect and process data. Machine learning is a sub-discipline of AI that involves the creation of algorithms capable of analyzing large datasets without making prior assumptions, while deep learning focuses on the construction and training of deep and complex artificial neural networks. The incorporation of AI systems to intravascular imaging methods improves the accuracy of PCI, reduces procedure duration, and minimizes interobserver variability in data interpretation. This promotes their wider adoption and facilitates their use. The aim of this review is to highlight how current AI-based systems can play a key role in the interpretation of data generated by intravascular imaging methods and optimize PCI in patients with CAD.

Adiponectin in Relation to Coronary Plaque Characteristics on Radiofrequency Intravascular Ultrasound and Cardiovascular Outcome / Relação da Adiponectina com as Características da Placa Aterosclerótica ao Ultrassom Intravascular com Radiofrequência e Desfechos Cardiovasculares

Abstract Background: Prospective data on the associations of adiponectin with in-vivo measurements of degree, phenotype and vulnerability of coronary atherosclerosis are currently lacking. Objective: To investigate the association of plasma adiponectin with virtual histology intravascular ultrasound (VH-IVUS)-derived measures of atherosclerosis and with major adverse cardiac events (MACE) in patients with established coronary artery disease. Methods: In 2008-2011, VH-IVUS of a non-culprit non-stenotic coronary segment was performed in 581 patients undergoing coronary angiography for acute coronary syndrome (ACS, n = 318) or stable angina pectoris (SAP, n = 263) from the atherosclerosis-intravascular ultrasound (ATHEROREMO-IVUS) study. Blood was sampled prior to coronary angiography. Coronary plaque burden, tissue composition, high-risk lesions, including VH-IVUS-derived thin-cap fibroatheroma (TCFA), were assessed. All-cause mortality, ACS, unplanned coronary revascularization were registered during a 1-year-follow-up. All statistical tests were two-tailed and p-values < 0.05 were considered statistically significant. Results: In the full cohort, adiponectin levels were not associated with plaque burden, nor with the various VH-tissue types. In SAP patients, adiponectin levels (median[IQR]: 2.9(1.9-3.9) µg/mL) were positively associated with VH-IVUS derived TCFA lesions, (OR[95%CI]: 1.78[1.06-3.00], p = 0.030), and inversely associated with lesions with minimal luminal area (MLA) ≤ 4.0 mm2 (OR[95%CI]: 0.55[0.32-0.92], p = 0.025). In ACS patients, adiponectin levels (median[IQR]: 2.9 [1.8-4.1] µg/mL)were not associated with plaque burden, nor with tissue components. Positive association of adiponectin with death was present in the full cohort (HR[95%CI]: 2.52[1.02-6.23], p = 0.045) and (borderline) in SAP patients (HR[95%CI]: 8.48[0.92-78.0], p = 0.058). In ACS patients, this association lost statistical significance after multivariable adjustment (HR[95%CI]: 1.87[0.67-5.19], p = 0.23). Conclusion: In the full cohort, adiponectin levels were associated with death but not with VH-IVUS atherosclerosis measures. In SAP patients, adiponectin levels were associated with VH-IVUS-derived TCFA lesions. Altogether, substantial role for adiponectin in plaque vulnerability remains unconfirmed.

Resumo Fundamento: Faltam dados prospectivos sobre as associações de adiponectina com medidas in-vivo de grau, fenótipo e vulnerabilidade da aterosclerose coronariana. Objetivo: Investigar a associação da adiponectina plasmática com medidas de aterosclerose derivadas de ultrassonografia virtual intravascular (VH-IVUS) e eventos cardíacos adversos importantes (major adverse cardiac events - MACE) em pacientes com doença arterial coronariana estabelecida. Métodos: Em 2008-2011, a VH-IVUS de um segmento coronariano não estenótico não culpado foi realizado em 581 pacientes submetidos à angiografia coronariana para síndrome coronariana aguda (SCA, n = 318) ou angina pectoris estável (APE, n = 263) a partir do estudo de ultrassonografia aterosclerótica-intravascular (ATHEROREMO-IVUS). Sangue foi amostrado antes da angiografia coronária. Foram avaliados a carga de placa coronária, a composição tecidual, as lesões de alto risco, incluindo fibroateroma de capa fina (FCF) derivado de VH-IVUS. Mortalidade por todas as causas, SCA, e revascularização coronária não planejada foram registradas durante um ano de acompanhamento. Todos os testes estatísticos foram bicaudais e os valores de p < 0,05 foram considerados estatisticamente significativos. Resultados: Na coorte completa, os níveis de adiponectina não foram associados à carga de placa, nem a vários tipos de tecido virtual histológico. Entre os pacientes com APE, os níveis de adiponectina (mediana[IIQ]: 2,9(1,9-3,9) µg/mL) foram associados positivamente às lesões FCF derivadas de VH-IVUS, (OR[IC 95%]: 1,78[1,06-3,00], p = 0,030), e inversamente associados a lesões com área luminal mínima (ALM) ≤4,0 mm2 (OR[IC 95%]: 0,55[0,32-0,92], p = 0,025). Em pacientes com SCA, os níveis de adiponectina (mediana[IIQ]: 2,9 [1,8-4,1] µg/mL) não foram associados à carga de placa nem a componentes teciduais. A associação positive de adiponectina ao óbito esteve presente na coorte completa (HR[IC 95%]: 2,52[1,02-6,23], p = 0,045) e (limítrofe) em pacientes com APE (HR[IC 95%]: 8,48[0,92-78,0], p = 0,058). Entre pacientes com SCA, essa associação perdeu significância estatística após ajuste multivariado (HR[IC 95%]: 1,87[0,67-5,19], p = 0,23). Conclusão: Na coorte completa, os níveis de adiponectina foram associados à obito, mas não a medidas de aterosclerose por VH-IVUS. Em pacientes com APE, os níveis de adiponectina foram associados a lesões FCF derivadas de VH-IVUS. Em geral, o papel da adiponectina na vulnerabilidade da placa permanece não confirmado.

Precisión diagnóstica de la angiografía coronaria por tomografía computarizada multislice aplicada al "mundo real" / Diagnostic accuracy of coronary angiography with multislice computed tomography

Objetivo: Evaluar la precisión diagnóstica de la angiografía coronaria por tomografía computarizada multislice (ACTCM) para la detección de estenosis significativas en arterias coronarias. Material y métodos: Se estudiaron pacientes con indicación de cinecoronariografía diagnóstica sin antecedentes de alergia al contraste, insuficiencia renal ni arritmias. Para la adquisición de imágenes se utilizó un tomógrafo multislice (multicorte) (Brilliance 40, Philips, The Netherlands) gatillado electrocardiográficamente. Se administraron 90-125 ml de contraste yodado por vía endovenosa. La obesidad, la diabetes, los segmentos difusamente calcificados, con diámetro < 2,0 mm, y aquellos tratados con stents no constituyeron criterios de exclusión. Las lesiones se definieron significativas cuando presentaron una reducción luminal ≥ 50 por ciento por ACTCM y angiografía cuantitativa coronaria (QCA). Resultados: Previo a la intervención se escanearon 38 pacientes. De ellos, uno (3 por ciento) fue excluido debido a calidad de imagen insuficiente. Los 37 restantes (444 segmentos), con calidad de scan satisfactoria, se incluyeron en el estudio (81 por ciento hombres, edad media 62,43 ± 12,5 años, 13,5 por ciento diabéticos). El tiempo medio de scan fue de 15,12 ± 2,6 segundos. Se analizaron 444 segmentos por ambas técnicas. Se encontraron 88 (17 por ciento) y 93 (18 por ciento) lesiones significativas por CCG y ACTCM, respectivamente. La sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de la ACTCM para detectar estenosis significativas fueron del 82 por ciento, 93 por ciento, 72 por ciento y 96 por ciento, respectivamente. Conclusión: En pacientes seleccionados para cinecoronariografía, la angiografía coronaria por tomografía computarizada multislice presenta un alto valor predictivo negativo para la detección de enfermedad obstructiva coronaria.

Drug-eluting stents

Stent implantation was developed to overcome the acute recoil and high restenosis rate of balloon angioplasty, but resulted in the development of chronic in-stent restenosis related to specific factors regarding patient, stent, lesion and procedural characteristics. Some factors are not modifiable, such as patient and lesion characteristics, whereas procedural characteristics may be improved by better implantation technique and stent design. Drug-eluting stents are a novel approach in stent technology and design with local drug delivery to inhibit intimal thickening by interfering with different pathways involved in the development of inflammation, migration, proliferation and/or secretion of the extracellular matrix. Both the drug and the delivery vehicle must fulfill pharmacological, pharmacokinetic and mechanical requirements. Current successful drug eluting stents require a polymer coating for drug delivery. Clinical trials examining several pharmaceutical agents, particularly sirolimus and paclitaxel, have demonstrated marked reduction in restenosis following stenting. Sirolimus is a natural macrocyclic lactone and paclitaxel is a cytotoxic agent against many tumors. Both compounds block cell cycle progression and thus inhibit smooth muscle cell proliferation. The development of drug-eluting stents is one of the major revolutions in the field of Interventional Cardiology. Restenosis rate has been significantly reduced, in comparison to bare metal stents. The ideal drug to prevent restenosis must have an anti-proliferative and anti-migratory effect on smooth muscle cells but on the other hand must also enhance re-endothelialization, in order to prevent late thrombosis. Additionally, it should effectively inhibit the anti-inflammatory response after balloon induced arterial injury. Currently sirolimus, paclitaxel and more recently, ABT-578-eluting stents are commercially available, but ongoing research and clinical trials will result in new stents coming to market with novel designs loaded with a variety of compounds. As drug-eluting stent implantation becomes more liberal leading to an extensive use of this technology, the problem of restenosis in drug-eluting stents will become more common. However, for the time being, little is known regarding optimal treatment of in-stent restenosis following drug-eluting stent implantation. Future research is mandatory to further clarify, whether these patients should be treated with the same drug-eluting sten.