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Background: Chronic total occlusions (CTO) are common and are associated with lower percutaneous coronary intervention (PCI) success rates, often due to failure of antegrade guidewire crossing. Local, intralesional delivery of collagenase (MZ-004) may facilitate guidewire crossing in CTO. Aims: To evaluate the effect of MZ-004 in facilitating antegrade wire crossing in CTO angioplasty. Methods: A total of 76 patients undergoing CTO PCI were enrolled at 13 international sites: 38 in the randomized training stage (collagenase [MZ-004] 900 or 1200 μg) and 38 in the placebo-controlled stage (MZ-004 900 or 1200 μg or placebo). Patients received the MZ-004 or identical volume saline (placebo group) in a double-blind design, injected via microcatheter directly into the proximal cap of the CTO. The following day patients underwent CTO PCI using antegrade wire techniques only. Results: Patients were generally similar except for a trend for higher Japanese chronic total occlusion (J-CTO) score in the MZ-004 group (MZ-004 J-CTO score 1.9 vs. 1.4, p = 0.07). There was a numerical increase in the rates of guidewire crossing in the MZ-004 groups compared to placebo (74% vs. 63%, p = 0.52). Guidewire crossing with a soft-tip guidewire (≤1.5 g tip load) was significantly higher in the MZ-004 groups (0% in placebo, 17% in 900 μg, and 29% in 1200 μg MZ-004 group, p = 0.03). Rates of the major adverse cardiovascular event were similar between groups. Conclusion: Local delivery of MZ-004 into coronary CTOs appears safe and may facilitate CTO crossing, particularly with softer tipped guidewires. These data support the development of a pivotal trial to further evaluate this agent.

Objectives. To compare long-term angina pectoris relief of successful versus failed percutaneous coronary intervention of chronic total occlusions (CTO PCI). Background. Previous studies demonstrate better short-term angina pectoris relief of CTO PCI than with optimal medical treatment (OMT), however, data on the long-term effects are lacking. Methods. 295 patients undergoing CTO PCI were analyzed retrospectively, with a follow-up evaluation of symptoms of angina pectoris and all-cause death one to four years after the intervention. The primary outcome was long-term relief of symptoms of angina pectoris. Secondary outcomes included a composite of major adverse cardiovascular events (MACE), including all-cause death, myocardial infarction, stroke, and later target vessel revascularization (TVR). At follow-up, patients were interviewed for symptoms of angina pectoris at 1, 6, 12, and 22 to 48 months after the intervention. Results. CTO PCI was successful in 225 (76%) patients and failed in 70 (24%) patients. Short-term (six months) relief of angina pectoris was observed in both groups, but only the successful CTO PCI group showed long-term relief. The Kaplan–Meier curves of all-cause death did not differ between the groups (p = .715). The final follow-up was a mean (range) of 37 (25 to 44) months after the intervention in the successful CTO PCI group, and 33 (28 to 48) months in the failed CTO PCI group. Conclusions. Successful CTO PCI is associated with better long-term relief of symptoms of angina pectoris compared to failed CTO PCI.

Tuotetiedon määrä on kasvanut räjähdysmäisesti valmistavassa teollisuudessa, ja erityisesti matalan volyymin ja korkean muunneltavuustason projektiliiketoiminnassa monet yritykset kamppailevat globaalissa toimintaympäristössä digitalisuuden kynnyksellä, jossa markkinoiden kilpailuasetelma edellyttää arvoketjuilta yhä nopeampia ja tehokkaampia sisäisiä prosesseja. Tuotekehityksen ja projektisuunnittelun näkökulmasta, jatkuvasti muuttuvat asiakasvaatimukset ja lyhyet läpivientiajat luovat paineita tuotetiedon laadulle, saavutettavuudelle ja uudelleenkäytettävyydelle sekä suunnittelutyön koordinaatiolle. Tietojärjestelmät ja erityisesti tuotteen elinkaaren hallintajärjestelmät (engl. Product Lifecycle Management system, PLM-system) ovat keskeisessä asemassa näiden haasteiden ratkaisemisessa. Tämän tutkimuksen tavoitteena on kartoittaa kohdeliiketoimintayksikön tuotetiedon hallinnan taso lähtötilanteessa suunnittelun näkökulmasta ja tunnistaa tärkeimmät käyttöönotettavat PLM-järjestelmän toiminnallisuudet, ja niiden mahdollistamat suunnittelun tuottavuutta parantavat toimintatavat ja toimenpiteet kirjallisuusselvityksen ja vertailuanalyysin avulla. Tutkimus on seurausta PLM-aloitteelle, jonka tarkoitus on harmonisoida prosessit, tietojärjestelmät ja toimintatavat liiketoimintalinjatasolla. Tutkimustulosten perusteella luodaan liiketoimintayksikkökohtainen PLM-järjestelmän käyttöönoton etenemissuunnitelma suunnittelun tuottavuuden parantamiseksi. Tutkimus on yhdistelmä laadullisia ja määrällisiä tutkimus- ja analysointimenetelmiä, jotka kokoavat liiketoimintayksikölle tietoa PLM-järjestelmän ja sen käyttöönoton edellyttämän transformaatiomuutoksen laajuudesta, mahdollisuuksista ja haasteista painottaen tuotekehityksen ja projektisuunnittelun tuottavuuden näkökulmaa. Diplomityön teoreettisen osuuden tuloksena syntyi yhteenveto, joka esittää PLM-järjestelmän toiminnallisuuksien yhteydet sen mahdollistamiin suunnittelun toimintatapoihin ja tunnistettuihin viiteen liiketoiminnan tehokkuuden ajuriin ja kokonaistuottavuuteen. Tunnistettuja toimenpiteitä ja yhteyksiä hyödynnettiin tutkimuksen empiirisessä osuudessa tapaustutkimuksena toteutettuun nykytilakartoitukseen, jossa tarkasteltiin kohdeliiketoimintayksikön lähtötilanteen toimintatapoja ja PLM-järjestelmän toiminnallisuuksia vastaavia tietoteknisiä ratkaisuja. Empiirisessä osuudessa luotiin tavoitetilakuvaus, jonka luomiseksi hyödynnettiin liiketoimintalinjan yhteisen PLM-strategian suuntaviivoja ja tapaustutkimuksina toteutettua vertailuanalyysiä, jossa selvitettiin, miten ja mitä PLM-järjestelmän toiminnallisuuksia ja toimintatapoja vertailtavat yritykset hyödyntävät toimintaympäristössään. Vertailuanalyysin tulokset osoittavat, että kohdeliiketoimintayksikön tuotetiedon hallinnan taso on verrattain alhainen suhteessa PLM-järjestelmää hyödyntäviin yrityksiin ja monet suunnittelun prosessit olivat hajautettuja ja manuaalisia, mikä johtui erityisesti tietoteknisen tuen puutteesta. Empiirisen ja teoreettisen osuuden ja laadullisten ja määrällisten analysointimenetelmien avulla luotiin Gap-analyysi, jonka perusteella luotiin liiketoimintayksikkökohtainen PLM-järjestelmän käyttöönoton etenemissuunnitelma suunnittelun tuottavuuden parantamiseksi. Kaiken kaikkiaan tämä tutkimus auttoi kohdeliiketoimintayksikköä ymmärtämään, miten PLM-järjestelmä voi parantaa suunnittelun tuottavuutta ja tehostaa tuotetiedon hallintaa. Etenemissuunnitelma tukee liiketoimintayksikön PLM-käyttöönottostrategian luomista ja kulttuurillisen transformaatiomuutoksen johtamista. The amount of product data has grown explosively in the manufacturing industry. Especially in low-volume and high-variability project business, many companies are struggling in a global operating environment on the threshold of digitalization, where value chains require increasingly faster and more efficient internal processes. From the perspective of product development and project engineering, constantly changing customer requirements and short delivery times create pressures on data quality, accessibility, and reusability, as well as on coordination of design work. Information systems, and especially Product Lifecycle Management (PLM) systems, play a key role in solving these challenges. The aim of this study is to assess the level of product data management in the target business unit from a design perspective and identify the key functionalities of the PLM system to be implemented, along with the design productivity-enhancing practices and actions enabled by them, through a literature review and comparative analysis. This research is a result of a PLM initiative aimed at harmonizing processes, information systems, and practices at the business line level. Based on the research results, a business unit-specific PLM system implementation plan to improve design productivity is created. The research is a combination of qualitative and quantitative research and analysis methods that provide information to the business unit about the extent of transformational change required for the implementation of PLM systems, opportunities, and challenges, emphasizing the productivity of product development and project engineering. As a result of the theoretical part of the thesis, a summary was created that presents the connections between the functionalities of the PLM system, the design practices it enables, and the five identified drivers of business effectiveness and overall productivity. This list of actions was used in the empirical part of the research, which involved a current situation assessment of the target business unit's practices and technological solutions that correspond to the PLM system's functionalities. A description of the target state was created by utilizing the guidelines of the business line's shared PLM strategy and results of comparative analysis performed as a case study, which examined how and what PLM system functionalities comparable companies utilize in their operational environment. The results of the comparative analysis indicate that the level of product data management in the target business unit is relatively low compared to companies utilizing PLM systems, and many design processes were decentralized and manual, primarily due to a lack of IT support. Through the empirical and theoretical sections and the use of qualitative and quantitative analysis methods, a Gap analysis was created, forming the basis for developing a business unit-specific PLM system implementation plan to enhance design productivity. Overall, this research helped the target business unit understand how a PLM system can improve design productivity and streamline product data management. The implementation plan supports the development of the business unit's PLM implementation strategy and the leadership of cultural transformational change.

[ES] La revascularización percutánea de las oclusiones totales crónicas (CTO) es uno de los procedimientos más complejos actualmente en el intervencionismo coronario percutáneo (ICP), que requiere la utilización de dispositivos específicos y una alta experiencia para la obtención de buenos resultados. Una vez establecida la indicación clínica por isquemia extensa o ángor no controlado con tratamiento médico la decisión de la realización del intervencionismo coronario no es sencilla ya que este procedimiento presenta una mayor tasa de complicaciones que el intervencionismo percutáneo no-CTO, mayor exposición a radiaciones ionizantes y una menor tasa de éxito. Sin embargo, la revascularización de CTO ha demostrado ser útil en la mejoría sintomática del ángor, reducción de la carga isquémica o mejoría de la fracción de eyección. Las técnicas de aprendizaje profundo o ¿deep-learning¿ permiten el análisis de grandes cantidades de datos multiformato (características clínicas, imagen, video, volumen) y realizar enfoques predictivos y de clasificación que han demostrado buenos resultados en múltiples aplicaciones clínicas. La finalidad de este Trabajo Fin de Grado es determinar si un modelo desarrollado con técnicas de aprendizaje profundo, entrenado con imágenes de angiografía, permite predecir mejor la dificultad de revascularización de CTO (medida como éxito del procedimiento y tiempo de fluoroscopia) que las escalas utilizadas tradicionalmente. Como aproximación preliminar se incluirán pacientes con CTO de arteria coronaria derecha ya que presentan proyecciones angiográficas estándar que se realizan en todos los pacientes y presentan menor variabilidad técnica (duración, ángulo de proyección, similitud de imágenes) entre ellas. El objetivo último es el desarrollo de un modelo predictivo que permita ayudar al clínico en la decisión de intervención y analizar el rendimiento en cuanto a predicción de éxito de la técnica de revascularización de oclusiones crónicas. Durante el desarrollo del presente Trabajo Fin de Grado se propondrán diferentes arquitecturas y parámetros para la optimización de la red neuronal a utilizar. Para ello se plantean diferentes arquitecturas en las cuales se experimentará con parámetros de red como el número de capas y la función de pérdidas entre otros. La evaluación de las distintas iteraciones de parámetros se realizará mediante métricas como la exactitud, la sensibilidad y las pérdidas del conjunto de entrenamiento y validación. Finalmente se evaluará la red con un conjunto de test con imágenes nunca vistas por la red., [EN] Percutaneous revascularization of chronic total occlusions (CTO) is currently one of the most complex procedures in percutaneous coronary intervention (PCI), requiring the use of specific devices and a high level of experience to obtain good results. Once the clinical indication for extensive ischemia or angina uncontrolled with medical treatment has been established, the decision to perform coronary intervention is not simple, since this procedure has a higher rate of complications than non-PCI percutaneous intervention, greater exposure to ionizing radiation and a lower success rate. However, CTO revascularization has been shown to be useful in symptomatic improvement of angina, reduction of ischemic burden or improvement of ejection fraction. Deep learning techniques allow the analysis of large amounts of multi-format data (clinical features, image, video, volume) and perform predictive and classification approaches that have shown good results in multiple clinical applications. The purpose of this Final Degree Project is to determine whether a model developed with deep learning techniques, trained with angiography images, can better predict the difficulty of CTO revascularization (measured as procedure success and fluoroscopy time) than the scales traditionally used. As a preliminary approach, patients with right coronary artery CTO will be included since they present standard angiographic projections that are performed in all patients and present less technical variability (duration, projection angle, image similarity) among them. The ultimate objective is to develop a predictive model to help the clinician in the decision to intervene and to analyze the performance in terms of predicting the success of the technique for revascularization of chronic occlusions. During the development of this Final Degree Project, different architectures and parameters will be proposed for the optimization of the neural network to be used. For this purpose, different architectures will be proposed in which we will experiment with network parameters such as the number of layers and the loss function, among others. The evaluation of the different parameter iterations will be performed using metrics such as accuracy, sensitivity and losses of the training and validation set. Finally, the network will be evaluated with a test set with images never seen by the network., [CA] La revascularització percutània de les oclusions totals cròniques (OTC) és un dels procediments més complexos actualment en l'intervencionisme coronari percutani (ICP), que requereix la utilització de dispositius específics i una alta experiència per a l'obtenció de bons resultats. Una vegada establida la indicació clínica per isquèmia extensa o àngor no controlat amb tractament mèdic la decisió de la realització de l'intervencionisme coronari no és senzilla ja que aquest procediment presenta una major taxa de complicacions que l'intervencionisme percutani no-OTC, major exposició a radiacions ionitzants i una menor taxa d'èxit. No obstant això, la revascularització de OTC ha demostrat ser útil en la millora simptomàtica del àngor, reducció de la càrrega isquèmica o millora de la fracció d'ejecció. Les tècniques d'aprenentatge profund o “deep-learning” permeten l'anàlisi de grans quantitats de dades multi format (característiques clíniques, imatge, vídeo, volum) i realitzar enfocaments predictius i de classificació que han demostrat bons resultats en múltiples aplicacions clíniques. La finalitat d'aquest Treball Fi de Grau és determinar si un model desenvolupat amb tècniques d'aprenentatge profund, entrenat amb imatges de angiografia, permet predir millor la dificultat de revascularització de OTC (mesura com a èxit del procediment i temps de fluoroscòpia) que les escales utilitzades tradicionalment. Com a aproximació preliminar s'inclouran pacients amb OTC d'artèria coronària dreta ja que presenten projeccions angiogràfiques estàndard que es realitzen en tots els pacients i presenten menor variabilitat tècnica (duració, angle de projecció, similitud d'imatges) entre elles. L'objectiu últim és el desenvolupament d'un model predictiu que permeta ajudar al clínic en la decisió d'intervenció i analitzar el rendiment quant a predicció d'èxit de la tècnica de revascularització d'oclusions cròniques. Durant el desenvolupament del present Treball Fi de Grau es proposaran diferents arquitectures i paràmetres per a l'optimització de la xarxa neuronal a utilitzar. Per a això es plantegen diferents arquitectures en les quals s'experimentarà amb paràmetres de xarxa com el nombre de capes i la funció de pèrdues entre altres. L'avaluació de les diferents iteracions de paràmetres es realitzarà mitjançant mètriques com l'exactitud, la sensibilitat i les pèrdues del conjunt d'entrenament i validació. Finalment s'avaluarà la xarxa amb un conjunt de test amb imatges mai vistes per la xarxa.

BackgroundCoronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment, but data on coronary hemodynamic changes in relation to myocardial function are limited. We assessed changes in coronary flow velocity reserve (CFVR) by echocardiography in collateral donor and recanalized artery following successful opening of coronary CTO.MethodsOur study enrolled 31 patients (60 ± 9 years; 22 male) with CTO and viable myocardium by SPECT scheduled for percutaneous coronary intervention (PCI). Non-invasive CFVR was measured in collateral donor artery before PCI, 24 h and 6 months post-PCI, and 24 h and 6 months in recanalized artery following successful PCI of CTO.ResultsCollateral donor artery showed significant increase in CFVR 24 h after CTO recanalization compared to pre-PCI values (2.30 ± 0.49 vs. 2.71 ± 0.45,p = 0.005), which remained unchanged after 6-months (2.68 ± 0.24). Baseline blood flow velocity of the collateral donor artery significantly decreased 24 h post-PCI compared to pre-PCI (0.28 ± 0.06 vs. 0.24 ± 0.04 m/s), and remained similar after 6 months, with no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24 h and 6 months post-PCI. CFVR of the recanalized coronary artery 24 h post-PCI was 2.55 ± 0.35, and remained similar 6 months later (2.62 ± 0.26, p = NS).ConclusionsIn patients with viable myocardium, prompt and significant CFVR increase in both recanalized and collateral donor artery, was observed within 24 h after successful recanalization of CTO artery, which maintained constant during the 6 months.Trial registrationClinicalTrials.gov (NumberNCT04060615).

Jańczyk Magdalena, Samek Ilona, Pachowicz Marcin. Myocardial blood flow assessment with myocardial perfusion scan in patients with coronary artery chronic total occlusion. Journal of Education, Health and Sport. 2020;10(6):275-285. eISSN 2391-8306. DOI http://dx.doi.org/10.12775/JEHS.2020.10.06.030 https://apcz.umk.pl/czasopisma/index.php/JEHS/article/view/JEHS.2020.10.06.030 https://zenodo.org/record/3923161 The journal has had 5 points in Ministry of Science and Higher Education parametric evaluation. § 8. 2) and § 12. 1. 2) 22.02.2019. © The Authors 2020; This article is published with open access at Licensee Open Journal Systems of Nicolaus Copernicus University in Torun, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike. (http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 01.06.2020. Revised: 15.06.2020. Accepted: 30.06.2020. Myocardial blood flow assessment with myocardial perfusion scan in patients with coronary artery chronic total occlusion Magdalena Jańczyk (1), Ilona Samek (1), dr n. med. Marcin Pachowicz (2) 1) Students Scientific Association at the Chair and Department of Nuclear Medicine, Medical University of Lublin 2) Chair and Department of Nuclear Medicine, Medical University of Lublin *Address for correspodence: Smolniki 7/12, 18-520 Stawiski, telephone number: 662237472, e-mail address: magdajanczyk7@gmail.com ORCID ID and e-mail: Magdalena Jańczyk: https://orcid.org/0000-0002-4948-9463; magdajanczyk7@gmail.com Ilona Samek: https://orcid.org/0000-0002-5538-5396; samekilona@gmail.com Marcin Pachowicz: https://orcid.org/0000-0002-0714-2170; marcin.pachowicz.md@gmail.com Abstract Introduction and purpose: Coronary artery disease (CAD) is a leading cardiological problem in modern society. A special form of CAD is the Chronic Total Occlusion (CTO), which affects about 20% of visible coronary artery lesions. The aim of the study is to present the role of myocardial perfusion scintigraphy performed on patients with CTO, and scintigraphic findings in these patients. Material and method: It was a retrospective study. We analized studies in patients with CTO reported in medical history. We included studies performed between 2016 and 2019. 119 cases were found with the majority of men (M = 95, W = 24). The patients’ mean age was 65 years (M = 65, W = 66). In order to assess ischemia in these patients, the stress test was applied by means of physical exercise (cycloerometer) or pharmacological test. If patient's clinical condition did not allow a stress test, only a rest test was performed. Results: In the analyzed group the most common occluded vessel was the right coronary artery (59%). In this case, mean ischaemia was found to cover 18% of the myocardium. The second most frequent obstructed vessel was the circumflex (16%) with ischaemia of 15%. The next artery was left anterior descending artery with ischaemia of 30% and other vessel - 7%. 9 patients had more than one vessel closed. Conclusions: Myocardial perfusion imaging helps to choose optimal treatment in patients with CTO. Key words: heart; scintigraphy; perfusion; CTO

This paper is a part of a natural dye solar cell project. Conductive transparent oxide (CTO) films have been deposited onto preheated glass substrates using a spray pyrolysis technique. The optical, electrical, structural properties as well as thermal annealing and gamma radiation response were studied. The average optical energy gap of doped films for direct allowed and direct forbidden transitions were found to be 3.92 and 3.68 eV, respectively. The plasmon frequency and plasmon energy after doping were found to be 3.48 × 1014 s −1 and 0.23 eV. The negative absorbance of the doped film was observed in UV-Vis range after applying both thermal annealing and γ-dose irradiation with 22 kGy. The negative refractive index of the doped film in UV range (220 – 300 nm) is promising for optical applications. The electron mobility μe reached a maximum of 27.4 cm2 V−1 s−1 for Sb concentration of 10 %. The corresponding resistivity ρ, and sheet resistance Rs reached their minimum values of 1.1 × 10−3 Ω cm and 35 Ω sq−1, respectively. The dopant concentration has been increased from 4.13 × 1019 to 2.1 × 1020cm−3. The doped film was found to exhibit three diffraction peaks associated with (2 2 2), (2 0 0), and (2 1 1) reflection planes, of which the peak of (2 2 2) of Sb2O3 and the peak of (2 0 0) were very close.

Aim Chronic total occlusion of a coronary artery (CTO) is a predictor of early and late cardiovascular mortality and poor cardiovascular outcomes in patients with coronary artery disease. The purpose of this study was to identify predictors of all-cause mortality in CTO patients that underwent invasive treatment.Material and methods Patients between 2012 and 2018 with CTO in at least one vessel, as demonstrated by coronary angiography, were included retrospectively in the study. The patients were divided into two groups, an intervention group (percutaneous and surgical revascularization) and a medical group.Results A total of 543 patients were studied, 152 females (28%) and 391 males (72%). The median follow-up period was 49 (26–72) mos. A total of 186 (34.2%) patients in the medical group and 357 (65.8%) patients in the invasive therapy group were followed. The 5-yr death rate was observed in 50 (26.9%) patients in the medical group and 53 (14.8%) patients in the intervention group, and it was found to be statistically higher in the medical group (p=0.001). In multivariable analysis, heart failure (odds ratio (OR): 1.92, 95% CI: 1.18-3.14; p=0.01), higher glucose levels (OR: 1.05, 95% CI: 1,02-1.08; p=0.04), lower albumin levels (OR: 0.49, 95% Cl: 0.32-0.72; p=0.001), SYNTAX score (OR: 1.03, 95% CI: 1.01-1.05; p=0.001), and CTO (≥2 occluded artery) (OR: 0.42, 95% CI: 0.22-0.72; p=0.01) were independent factors for all-cause mortality.Conclusion In comparison to the revascularized group, there was an increase in mortality among CTO patients treated medically. Heart failure, SYNTAX score, albumin, glucose, and CTO (≥2 occluded arteries) were independent risk factors for all-cause mortality.

El treball de la tesi actual es tracta d'una anàlisi exhaustiva de la cohort de *ICPs sobre *OTCs del nostre centre al llarg de diversos anys des de l'establiment d'un programa dedicat a aquest camp. En el primer estudi s'ha estudiat la capacitat predictiva de J-*CTO *score en una cohort de més 500 pacients i s'ha investigat si el model pot predir adequadament l'èxit de procediment tenint en compte l'experiència progressiva del centro en aquest terreny. A ressaltar que J-*CTO *score va ser elaborat a partir d'una cohort de *ICPs sobre *CTOs dutes a terme per operadors experts. En el segon estudi hem analitzat les variables que millor prediuen les taxes d'èxit del procediment en la nostra cohort i hem inclòs la variable experiència de l'operador com un potencial factor influent, aspecte no quantificat en altres estudis. El tercer estudi analitza i compara aquelles *OTCs amb *ICP fallida i que van ser sotmeses a un segon intent amb les *ICPs de primer o de només un intent. Es fa una comparació del grau de complexitat i de les taxes d'èxit entre tots dos grups. Es busca i s'analitza específicament aquells possibles factors contribuents a l'èxit de procediment en el nou intent com a canvis *angiográficos en segon intent respecte al previ i la utilització de noves estratègies i tècniques en nous intents. El trabajo de la tesis actual se trata de un análisis exhaustivo de la cohorte de ICPs sobre OTCs de nuestro centro a lo largo de varios años desde el establecimiento de un programa dedicado a este campo. En el primer estudio se ha estudiado la capacidad predictiva de J-CTO score en una cohorte de más 500 pacientes y se ha investigado si el modelo puede predecir adecuadamente el éxito de procedimiento teniendo en cuenta la experiencia progresiva del centro en este terreno. A resaltar que J-CTO score fue elaborado a partir de una cohorte de ICPs sobre CTOs llevadas a cabo por operadores expertos. En el segundo estudio hemos analizado las variables que mejor predicen las tasas de éxito del procedimiento en nuestra cohorte y hemos incluido la variable experiencia del operador como un potencial factor influyente, aspecto no cuantificado en otros estudios. El tercer estudio analiza y compara aquellas OTCs con ICP fallida y que fueron sometidas a un segundo intento con las ICPs de primer o de sólo un intento. Se hace una comparación del grado de complejidad y de las tasas de éxito entre ambos grupos. Se busca y se analiza específicamente aquellos posibles factores contribuyentes al éxito de procedimiento en el nuevo intento como cambios angiográficos en segundo intento respecto al previo y la utilización de nuevas estrategias y técnicas en nuevos intentos. The work of the current thesis deals with an exhaustive analysis of the cohort of PCIs on OTCs of our center over several years since the establishment of a program dedicated to this field. In the first study, the predictive capacity of the J-CTO score was studied in a cohort of more than 500 patients and it was investigated whether the model can adequately predict the success of the procedure, taking into account the progressive experience of the center in this field. It should be noted that the J-CTO score was developed from a cohort of ICPs on CTOs carried out by expert operators. In the second study we have analyzed the variables that best predict the success rates of the procedure in our cohort and we have included the operator experience variable as a potential influencing factor, an aspect not quantified in other studies. The third study analyzes and compares those OTCs with failed PCI and who underwent a second attempt with the PCIs of the first or only one attempt. A comparison of the degree of complexity and the success rates between both groups is made. Those possible contributing factors to the success of the procedure in the new attempt are specifically sought and analyzed, such as angiographic changes in the second attempt compared to the previous one and the use of new strategies and techniques in new attempts.

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Objective To evaluate predictors of procedural success of percutaneous coronary intervention (PCI) of chronic total coronary occlusions (CTOs) in a non-infarct-related artery following ST-segment elevation myocardial infarction (STEMI), and demonstrate the effect on left ventricular functionality (LVF), infarct size (IS), and pro-arrhythmic electrocardiogram (ECG) parameters. Background Predictors of unsuccessful revascularization of a CTO are numerous, although following STEMI, these are lacking. Besides, effects of failed CTO PCI (FPCI) on the myocardium are unknown. Methods This is a subanalysis of the EXPLORE trial, in which 302 STEMI patients with a concurrent CTO were randomized to CTO PCI (n = 147) or no-CTO PCI (NPCI, n = 154). For the purpose of this subanalysis, we divided patients into successful CTO PCI (SPCI, n = 106), FPCI (n = 41), and NPCI (n = 154) groups. Cardiac magnetic resonance imaging and angiographic data were derived from the EXPLORE database, combined with ECG parameters. To gain more insight, all outcomes were compared with patients that did not undergo CTO PCI. Results In multivariate regression, only CTO lesion length >20 mm was an independent predictor of procedural failure (OR 3.31 [1.49-7.39]). No significant differences in median left ventricular ejection fraction, left ventricular end-diastolic volume, IS, and the pro-arrhythmic ECG parameters such as QT-dispersion, QTc-time, and TpTe-intervals were seen between the SPCI and FPCI groups at 4 months follow-up. Conclusion This subanalysis of the EXPLORE trial has demonstrated that a CTO lesion length >20 mm is an independent predictor of CTO PCI failure, whereas procedural failure did not lead to any adverse effects on LVF nor pro-arrhythmic ECG parameters.