A bifurcation identifier for IV-OCT using orthogonal least squares and supervised machine learning.

Intravascular optical coherence tomography (IV-OCT) is an in-vivo imaging modality based on the intravascular introduction of a catheter which provides a view of the inner wall of blood vessels with a spatial resolution of 10-20 µm. Recent studies in IV-OCT have demonstrated the importance of the bifurcation regions. Therefore, the development of an automated tool to classify hundreds of coronary OCT frames as bifurcation or nonbifurcation can be an important step to improve automated methods for atherosclerotic plaques quantification, stent analysis and co-registration between different modalities. This paper describes a fully automated method to identify IV-OCT frames in bifurcation regions. The method is divided into lumen detection; feature extraction; and classification, providing a lumen area quantification, geometrical features of the cross-sectional lumen and labeled slices. This classification method is a combination of supervised machine learning algorithms and feature selection using orthogonal least squares methods. Training and tests were performed in sets with a maximum of 1460 human coronary OCT frames. The lumen segmentation achieved a mean difference of lumen area of 0.11 mm(2) compared with manual segmentation, and the AdaBoost classifier presented the best result reaching a F-measure score of 97.5% using 104 features.

Aterectomia rotacional em artérias com calcificação extrema ou falha em dilatação prévia: aspectos técnicos e evolução tardia após intervenção coronária percutânea / Rotational atherectomy in arteries with extreme calcification or previous failed dilation: technical aspects and late outcomes after percutaneous coronary intervention

A aterectomia rotacional com incorporação de novas estratégias ablativas tem sido proposta para o preparo de lesões extremamente calcificadas. Entretanto, pouco se conhece a respeito da adoçãodessas novas estratégias na prática contemporânea e sobre a evolução tardia dos pacientes submetidos aesse tratamento. Objetivamos avaliar os aspectos técnicos da aterectomia e a evolução tardia dos pacientesquanto à ocorrência de eventos cardiovasculares adversos maiores (ECAM). Métodos: Estudo retrospectivo e unicêntrico, incluindo todos os pacientes submetidos à aterectomiarotacional como parte do tratamento de lesões coronárias com calcificação extrema ou falha de dilataçãoem procedimento prévio, no período de julho de 2012 a novembro de 2014. Foram definidos como ECAM: óbito, infarto agudo do miocárdio com onda Q ou nova revascularização do vaso-alvo.Resultados: Foram submetidos à aterectomia 29 pacientes com idade média de 69,5 ± 7,6 anos. A médiada relação oliva/vaso foi de 0,54 ± 0,07; a velocidade de rotação inicial adotada foi de 161.000 ± 13.928 e a taxa de utilização de cutting balloon pós-aterectomia foi de 45,1%. Sucesso angiográfico foi obtido em todos os procedimentos. Na evolução tardia, a mediana de tempo de seguimento foi de 13,2 meses (intervalo interquartil: 4,0 a 17,4 meses). Foram registrados um óbito por causa não cardíaca e duas novas revascularizações do vaso-alvo. A média do tempo de sobrevivência livre de ECAM foi de 29,7 ± 2,1 meses.Conclusões: A aterectomia rotacional contemporânea incorporou estratégias menos agressivas de ablação,com elevada taxa de sucesso imediato e baixa ocorrência de ECAM na evolução tardia...

Rotational atherectomy with new ablative strategies have been proposed for the treatment of extremely calcified lesions prior to stent implantation. Nevertheless, few data are available about the adoption of these new strategies in contemporary practice and about late outcomes of patients undergoing this therapy. Methods: From July 2012 to November 2014, a retrospective single center registry was conducted, including all patients undergoing rotational atherectomy as part of the treatment of coronary arteries with heavy calcification or previous failed dilation. We evaluated technical aspects of atherectomy and late outcomes of patients for the occurrence of major adverse cardiovascular events (MACE), defined as death, Q-wave myocardial infarction or repeat target vessel revascularization.Results: Twenty-nine patients with a mean age of 69.5 ± 7.6 years, underwent atherectomy. The averageburr-to-artery ratio was 0.54 ± 0.07, the initial rotational speed was 161.000 ± 13.928 and the rate of cuttingballoon utilization after atherectomy was 45.1%. Angiographic success was achieved in all procedures. The median follow-up time was 13.2 months (IQ: 4.0-17.4) and there were three events: 1 death of non cardiac cause and 2 new target vessel revascularizations. The mean MACE-free survival time was 29.7 ± 2.1 months. Conclusions: Contemporary rotational atherectomy incorporates less aggressive strategies of ablation with high rates of acute success and low occurrence of major adverse cardiovascular events during late follow-up...