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Transcatheter heart valve embolization is a serious and rare complication of transcatheter aortic valve replacement. Having a strategy for promptly managing transcatheter heart valve embolization is crucial to avoid emergency conversion from transcatheter aortic valve replacement to open-heart surgery. Many cases of transcatheter heart valve embolization occurring with balloon-expandable prostheses such as the SAPIEN 3 (Edwards LifeSciences Corporation) valve and self-expandable prostheses such as the ACURATE neo (Boston Scientific Corporation) valve have been reported in the literature. Here, for the first time (to the authors’ knowledge), the case of a Myval (Meril Life Sciences Pvt Ltd) transcatheter heart valve embolization during transcatheter aortic valve replacement, which was treated percutaneously with favorable outcomes, is reported.

RESUMEN Introducción y objetivos: El uso contemporáneo y los resultados de la aterectomía coronaria con láser Excímer (ELCA) en el intervencionismo coronario percutáneo (ICP) de lesiones coronarias gravemente calcificadas no están establecidos. El objetivo de este estudio fue evaluar la eficacia, seguridad y resultados a 1 año de ELCA en este escenario. Métodos: Se revisaron de forma retrospectiva las características clínicas y angiográficas, y los resultados de los procedimientos de revascularización de lesiones gravemente calcificadas tratadas con ICP asistido por ELCA en nuestro centro entre 2016 y 2022. Resultados: Se incluyeron 78 pacientes consecutivos (80 procedimientos) (edad media 71,2 ± 8,6 años, 80,5% varones). La presentación clínica fue enfermedad arterial coronaria estable en 45 (56,2%) pacientes y síndromes coronarios agudos en 33 (43,8%). Todas las lesiones presentaban calcificación grave. Además, el 40% eran lesiones incruzables, el 28,75% lesiones indilatables, el 2,5% reestenosis intrastent, el 6,25% infraexpansión del stent y el 7,5% oclusiones crónicas. La combinación de ≥ 2 de los escenarios anatómicos anteriores existió en el 12,5% de los procedimientos. La fluencia máxima fue de 73 ± 9,6 mJ/mm2 y la frecuencia máxima de 72,7 ± 10,4 Hz. ELCA con lavado con solución salina se utilizó inicialmente en todos los procedimientos y se utilizó contraste en 2 procedimientos. La tasa de éxito de ELCA y de éxito técnico fueron del 91,25 %. Fueron necesarias terapias adyuvantes de modificación de placa en 4 casos. La tasa de éxito clínico fue del 87,5%. Ocurrieron complicaciones relacionadas con ELCA en 2 (2,5%) procedimientos. Tras una mediana de seguimiento de 15,5 meses (IQR, 5,0-29,3), se produjeron eventos cardiovasculares adversos mayores (MACE) (nueva revascularización de la lesión diana, infarto de miocardio o muerte cardiaca) en 9 pacientes (11,25%). Conclusiones: A pesar de la complejidad de la ICP en lesiones gravemente calcificadas, ELCA demostró ser efectivo con una incidencia relativamente baja de complicaciones relacionadas con ELCA y MACE en el seguimiento.

ABSTRACT Introduction and objectives: No previous studies have established the contemporary use and outcomes of Excimer laser coronary atherectomy (ELCA) in percutaneous coronary intervention (PCI) of severely calcified coronary lesions. The aim of this study was to assess the safety, efficacy, and 1-year outcomes of ELCA in this setting. Methods: We retrospectively examined the clinical and angiographic characteristics and procedural outcomes of severely calcified lesions treated with ELCA-assisted PCI in our institution between 2016 and 2022. Results: Seventy-eight consecutive patients (80 procedures) were included (mean age 71.2 ± 8.6 years, 80.5% men). Clinical presentation was stable coronary artery disease in 45 patients (56.2%) and acute coronary syndromes in 33 (43.8%). All the lesions were severely calcified. In addition, 40% were uncrossable lesions, 28.75% were undilatable lesions, 2.5% showed in-stent restenosis, 6.25% showed stent underexpansion, and 7.5% were chronic total occlusions. The combination of ≥ 2 of the above anatomic settings was found in 12.5% of the procedures. The maximum fluence was 73 ± 9.6 mJ/mm2, and the maximum frequency was 72.7 ± 10.4 Hz. The saline flushing technique was initially used in all the procedures, while contrast was used in 2 procedures. The ELCA success and technical success rates were both 91.25%. Adjuvant plaque modification therapies were required in 4 patients. The clinical success rate was 87.5%. ELCA-related complications occurred in 2 procedures (2.5%). After a median follow-up of 15.5 months [IQR, 5.0-29.3], major adverse cardiac events (MACE) (target lesion revascularization, myocardial infarction or cardiac death) occurred in 9 patients (11.25%). Conclusions: Despite the complexity of PCI in severely calcified lesions, ELCA was effective with a relatively low incidence of ELCA-related complications and MACE during follow-up.

RESUMEN Introducción y objetivos: La calcificación coronaria es uno de los principales factores que inciden negativamente en la seguridad y la eficacia del intervencionismo coronario percutáneo. Existen varias técnicas de modificación del calcio, pero falta evidencia de estudios aleatorizados sobre la terapia de elección en este escenario. Métodos: El ROLLERCOASTR es un estudio prospectivo, multicéntrico y aleatorizado, diseñado para comparar la seguridad y la eficacia de 3 técnicas de modificación de la placa en el contexto de calcificación coronaria moderada o grave: aterectomía rotacional (AR), aterectomía coronaria con láser láser excimer (ACLE) y litotricia intracoronaria (LIC). El objetivo primario es la expansión del stent evaluada mediante tomografía de coherencia óptica. Su análisis se hará por intención de tratar, con un α de 0,05 entre el grupo de referencia (AR) y cada uno de los otros grupos (ACLE y LIC). Se realizará también un análisis del objetivo primario por protocolo para mantener la coherencia. Si se confirma la hipótesis de no inferioridad, se realizará un análisis bilateral de superioridad. El comité de eventos clínicos y el laboratorio central independiente no conocerán la rama de tratamiento. Asumiendo un error α de 0,05, un error β de 0,2 (80% de potencia), un margen de irrelevancia (ε) del 7% y un 10% de pérdidas por dificultad de medición o imposibilidad de completar la intervención, se estima un tamaño de muestra de 56 casos en cada grupo. Los objetivos secundarios son el éxito del dispositivo, el éxito del procedimiento, la tasa de cruce entre técnicas y la presentación de eventos cardiovasculares adversos importantes al año de seguimiento. Conclusiones: El estudio ROLLERCOASTR evaluará y comparará la seguridad y la eficacia, en pacientes con estenosis coronaria calcificada, de 3 técnicas de modificación de placa: AR, ACLE y LIC. Este ensayo se ha registrado en Clinicaltrials.gov: NCT04181268.

ABSTRACT Introduction and objectives: Coronary calcification is one of the leading factors that affect negatively the safety and effectiveness of percutaneous coronary intervention. Several calcium modification techniques exist. However, there is a lack of randomized evidence on the therapy of choice in this scenario. Methods: The ROLLERCOASTR is a prospective, multicenter, randomized clinical trial designed to compare the safety and efficacy profile of 3 plaque modification techniques in the moderate-to-severe coronary calcification setting: rotational atherectomy (RA), excimer laser coronary angioplasty (ELCA), and intravascular lithotripsy (IVL). The study primary endpoint is stent expansion evaluated by optical coherence tomography. An intention-to-treat analysis will be conducted with an alpha coefficient of 0.05 between the reference group (RA) and the remaining 2 groups (ELCA and IVL). An analysis of the study primary endpoint per protocol will be conducted for consistency purposes. If the non-inferiority hypothesis is confirmed, a superiority 2-sided analysis will be conducted. Both the clinical events committee and the independent core laboratory will be blinded to the treatment arm. Assuming an α error of 0.05, an β error of 0.2 (80% power), a margin of irrelevance (ε) of 7, and losses of 10% due to measurement difficulty or impossibility to complete the intervention, we estimate a sample size of 56 cases per group. The study secondary endpoints are device success, procedural success, crossover rate among the different techniques used, and the occurrence of major adverse cardiovascular events at 1-year follow-up. Conclusions: The ROLLERCOASTR trial will evaluate and compare the safety and effectiveness of 3 plaque modification techniques: RA, ELCA, and IVL in patients with calcified coronary stenosis. This trial was registered at clinicaltrials.gov with identifier NCT04181268.

RESOLUCIÓN DEL CASO Ante la imposibilidad de retirar el Impella 5.0 (figura 1), y debido al riesgo quirúrgico (EuroSCORE II 48,9%, Society of Thoracic Surgeons score 16%), se decidió realizar una reparación mitral percutánea con un dispositivo MitraClip (Abbott Laboratories, Estados Unidos). Con el soporte de Impella 5.0 a 2 l/min y bajo control con ecocardiograma transesofágico, se implantó un MitraClip NTW a nivel de A3-P3 (mayor orificio de regurgitación), con lo que se logró una reducción del chorro de insuficiencia (vídeos 1 y 2 del material adicional), una mejoría del flujo en las venas pulmonares y un gradiente transmitral de 4 mmHg. Se reevaluó el resultado disminuyendo transitoriamente el soporte hemodinámico a 1 l/min y se observó un chorro central de grado III-IV. Se implantó un segundo clip NT a nivel de A2-P2 (vídeos 3 y 4 del material adicional). Durante su posicionamiento hubo dificultades por interferencia con el Impella 5.0, por lo que fueron necesarias maniobras de inversión del dispositivo hacia la aurícula. Finalmente se realizó captura o prensión, que fue eficaz y se confirmó la ausencia de insuficiencia mitral residual, aunque hubo un aumento del gradiente transmitral hasta 7 mmHg. Tras reducir el soporte hemodinámico a 0,5 l/min, el...

CASE RESOLUTION Given the impossibility to remove the Impella 5.0 device (figure 1) and due to the high surgical risk involved (EuroSCORE II, 48,9%; Society of Thoracic Surgeons score (STS), 16%), percutaneous mitral valve repair was attempted with a MitraClip device (Abbott Laboratories, United States). Figure 1. Normal position of the Impella device as seen on the transesophageal echocardiography. With support from an Impella 5.0 device at a rate of 2 L/min and under transesophageal echocardiography guidance the MitraClip NTW device was implanted at A3-P3 level (greater effective regurgitant orifice area), which resulted in a reduced regurgitant jet (videos 1 and 2 of the supplementary data), improved blood flow into the pulmonary veins, and a transmitral gradient of 4 mmHg. Result was reassessed by reducing hemodynamic support temporarily at 1 L/min. A grade III-IV central regurgitant jet was seen. A second MitraClip NT was implanted at A2-P2 level (videos 3 and 4 of the supplementary data). Difficulties during its positioning due to interference with the Impella 5.0 device were reported, which is why reversal maneuvers towards the atrium were performed. Finally, capture or grasping turned out effective, and the lack of residual mitral regurgitation was confirmed. However, although transmitral gradient increased up to...

Un varón de 78 años con enfermedad coronaria revascularizada 10 años antes (descendente anterior y circunfleja) ingresa en el hospital por síndrome coronario agudo sin elevación del segmento ST. Por angiografía se detecta una imagen en la descendente anterior proximal inusual que parece originar una estenosis angiográficamente significativa (figura 1A,B). Para confirmar el diagnóstico, se intenta avanzar el catéter de tomografía de coherencia óptica (OCT) a través de una guía polimérica, sin conseguir atravesar la zona más estenótica. Se reintenta la maniobra tras predilatar en dos ocasiones (con balones de 1,5 y 2,5 mm de diámetro), sin resultado. Posteriormente, se decide avanzar un catéter de extensión de guía (figura 1D) que consigue atravesar la lesión y realizar la OCT, la cual muestra un stent no expandido, totalmente endotelizado, con un posible trombo adherido (figura 1C). Ante la sospecha de que esta sea la lesión culpable, se decide tratarla. Con el objetivo de aplastar el stent no expandido contra la luz del propio vaso (crush), primero se predilata con un balón de 3,5 × 12 mm sin dificultad y a continuación se implanta un stent farmacoactivo de 3,5 × 15 mm, con buen resultado angiográfico (figura 1E). Una nueva OCT...

This is the case of a 78-year-old man with revascularized coronary artery disease 10 years ago (left anterior descending coronary artery and left circumflex artery) who was admitted to the hospital with signs of ST-segment elevation acute coronary syndrome. The angiography shows an unusual image on the proximal left anterior descending coronary artery that seems to be causing an angiographically significant stenosis (figure 1A,B). To confirm diagnosis, a catheter is unsuccessfully advanced with optical coherence tomography (OCT) guidance through a polymeric guidewire while trying to cross the most stenotic region. Two attempts are made after predilatation (with balloons of 1.5 mm and 2.5 mm in diameter) that prove unsuccessful. Afterwards, a guide catheter extension system is advanced (figure 1D) that successfully crosses the lesion facilitating the OCT that reveals the presence of an underexpanded coronary stent with complete endothelization, and a possible thrombus attached to it (figure 1C). Upon suspicion that this is the culprit lesion, decision is made to treat it. To crush the underexpanded stent against the lumen of the vessel, it is first effortlessly predilated using a 3.5 mm x 12 mm balloon. Afterwards, a 3.5 mm x 15 mm drug-eluting stent is implanted with good angiographic...

Abstract Background Since the last century, the electrocardiogram (ECG) remains the non‐invasive test, that is, most easily accessible, feasible, and inexpensive for cardiology assessment. In past years, many novel ECG indexes and patterns have been published that allow for a more advanced evaluation of what is currently being done, especially based on subtle QRS changes and patterns. Objective The objective of the study was to provide an update on the evidence and clinical applications of these ECG subtle QRS changes and patterns associated with heart disease. Methods Through the literature review, we will highlight the subtle QRS changes and patterns associated with heart disease, mainly focusing on QRS duration, voltage, morphology, axis, and QT interval. Results Small increases in QRS duration are associated with a reduction in left ventricular ejection fraction (EF), increased cardiac chamber dimensions, and risk for incident heart failure (HF). Moreover, fragmentation of the QRS complex is associated with myocardial fibrosis and is a substrate for developing arrhythmic events. Besides, low amplitude QRS voltage is associated with congestive HF, and an increase in the voltage of the QRS complexes is associated with the effectiveness of diuresis treatment. Furthermore, small increases in QT interval are associated with diastolic dysfunction due to impaired sarcoplasmic reticulum calcium handling as occurs in myocardial ischemia, hypertension, or diabetes. On the other hand, in patients with left ventricular dysfunction, the QRS area is associated with clinical and echocardiographic response to cardiac resynchronization therapy regardless of the type of bundle branch block. In addition, subtle ECG changes and patterns in the left bundle branch block are associated with concomitant right ventricular dilation, mostly based on the QRS axis and voltage. Notwithstanding, to identify these subtle changes in QRS require exact manual measurements that can take time. In this regard, applying artificial intelligence (AI) to the ECG can make a quicker and more complete assessment, as well as provide a low cost when applied to large populations. Conclusion We provided an update on the evidence and clinical applications of these subtle QRS changes and patterns associated with diastolic dysfunction, reduced EF, and HF development and therapy responsiveness, as well as their applications for AI to ECG.

ABSTRACT Introduction and objectives: The Lotus Valve device (Boston Scientific) is a second-generation fully-retrievable and repositionable transcatheter aortic valve. We report the initial multicenter experience with the Lotus valve in the management of patients with severe aortic stenosis. Methods: Observational study that described the short and long-term results of implanting the Lotus valve in 8 Spanish and Portuguese centers from March 2014 through April 2016. Results: The study included 102 patients (mean age 80.4 ± 6.1 years; STS score 5.2% ± 3.3%) with severe symptomatic aortic stenosis (mean aortic valve area 0.66 ± 0.17 cm2, aortic gradients 74.3 / 45.6 mmHg). The valve was successfully implanted in 100 patients (98%), with significant improvement in both the peak and mean aortic valve gradients and with only one patient showing moderate paravalvular regurgitation. Upon hospital discharge, mortality rate was 3.9% while the stroke rate was 2.9%. No cases of valve embolization, ectopic valve deployment or additional valve implantation (valve-in-valve) were seen. Thirty-three patients (32.3%) received a permanent pacemaker. Conclusions: The Lotus Valve System is effective and safe for the management of patients with severe symptomatic aortic stenosis. In particular, considering the low rate of periprosthetic regurgitation and lack of complications like embolization or ectopic valve deployment; however at the expense of a high pacemaker implantation rate.

RESUMEN Introducción y objetivos: El dispositivo Lotus (Boston Scientific, Estados Unidos) es una prótesis valvular aórtica transcatéter de segunda generación, completamente recuperable y reposicionable. Se presenta la experiencia inicial con la prótesis Lotus en un registro multicéntrico. Métodos: Estudio observacional que reporta los resultados a corto y largo plazo del implante transfemoral de prótesis Lotus entre marzo de 2014 y abril de 2016 en 8 centros de España y Portugal. Resultados: Se incluyeron 102 pacientes (edad media 80,4 ± 6,1 años, índice STS medio 5,2% ± 3,3%) con estenosis aórtica grave sintomática (área valvular media 0,66 ± 0,17 cm2, gradientes 74,3/45,6 mmHg). Se implantó con éxito el dispositivo en 100 pacientes (98%), con mejoría significativa de los gradientes máximo y medio valvular, y un solo caso de regurgitación periprotésica moderada. No hubo ninguna embolización ni necesidad de implante de una nueva prótesis intravalvular. Hasta el alta hospitalaria, la mortalidad fue del 3,9% y la tasa de ictus fue del 2,9%. En 33 pacientes (32,3%) fue necesario el implante de marcapasos definitivo. Conclusiones: La válvula Lotus es eficaz y segura para el tratamiento de pacientes con estenosis aórtica grave sintomática. Destacan la escasa tasa de insuficiencia periprotésica y la ausencia de complicaciones derivadas del mal posicionamiento o la embolización de la prótesis, a costa de un alta incidencia de implante de marcapasos.

RESUMEN Introducción y objetivos: El objetivo del estudio fue investigar si la evaluación no invasiva del índice de calcificación coronaria mediante tomografía computarizada cardiaca multidetector (TCMD) puede predecir la necesidad de una aterectomía rotacional (AR) electiva durante la intervención coronaria percutánea. Métodos: Se incluyeron pacientes diagnosticados de estenosis coronaria grave con placas moderadamente o gravemente calcificadas durante la angiografía coronaria. Esos pacientes se sometieron a la cuantificación del índice de calcificación coronaria con la escala de Agatston utilizando TCMD y posteriormente a intervención percutánea. Solo fueron tratadas con AR las lesiones que se consideraba que no era posible cruzar ni dilatar, según un protocolo de revascularización prediseñado. Ninguno de los operadores conocía de antemano los resultados de la TCMD. Según el protocolo del estudio, en el análisis estadístico se incluyeron variables clínicas, angiográficas y relacionadas con la puntuación Agatston. Durante el seguimiento se estudiaron los resultados a corto y largo plazo en ambos grupos. Resultados: Se analizaron 40 pacientes: 20 que recibieron AR y 20 con intervención coronaria percutánea convencional. La mayoría se incluyó después de un síndrome coronario agudo y tenían una anatomía coronaria compleja (puntuación media de la escala Syntax de 25 puntos). La creatinina y la puntuación de Agatston por lesión fueron los únicos factores predictivos de la AR. No se observaron diferencias significativas en el pronóstico dentro del hospital o a largo plazo. Un nuevo parámetro, el índice CAC-Cre, fue útil para predecir la necesidad de AR. Conclusiones: El análisis de la calcificación de las arterias coronarias mediante la puntuación de Agatston mejora la evaluación no invasiva de las placas coronarias complejas antes de la intervención coronaria percutánea. La puntuación de Agatston por lesión, la creatinina sérica y el índice CAC-Cre son parámetros útiles para predecir la necesidad de una AR electiva durante la intervención coronaria percutánea.

ABSTRACT Introduction and objectives: This study aims to investigate if the non-invasive assessment of coronary calcium score using multislice cardiac computerized tomography (MSCT) may anticipate the need for elective rotational atherectomy (RA) during percutaneous coronary intervention. Methods: Patients were considered eligible for the study after receiving a diagnosis of severe coronary stenosis with moderate or severely calcified plaques during index coronary angiography. Those patients underwent the Agatston coronary artery calcium (CAC) score quantification using the MSCT and then underwent percutaneous intervention. Only those lesions considered non-crossable or non-dilatable according to a pre-specified revascularization protocol were treated with RA. All operators were blinded to the MSCT results. According to the study protocol, clinical, angiographic and Agatston-related variables were included in the statistical analysis. Short and long-term outcomes were investigated in both treatment groups during follow-up. Results: A total of 40 patients were included in the analysis: 20 underwent RA and 20 conventional percutaneous coronary interventions. Most patients were included after suffering from an acute coronary syndrome and had complex coronary anatomy (mean Syntax score, 25 points). The logistic regression analysis showed that creatinine levels and the per-lesion Agatston score were the only predictors of RA. No significant differences were observed regarding in-hospital or long-term procedural outcomes. A novel parameter, the CAC-Cre index, was found to be useful to anticipate the need for RA. Conclusion: Coronary artery calcification analysis using the Agatston score is a simple technique that improves the non-invasive assessment of complex coronary plaques prior to percutaneous coronary intervention. The per-lesion Agatston score, serum creatinine levels, and the CAC-Cre index may become useful parameters to anticipate the need for elective RAs during percutaneous coronary intervention.

Se presenta el caso de un varón de 74 años ingresado por síndrome coronario agudo sin elevación del segmento ST. La coronariografía realizada mostró una estenosis de la arteria coronaria derecha con un aneurisma coronario (AC) gigante y alta carga trombótica (figura 1A). Se recomendó doble antiagregación y anticoagulación oral para excluir el AC en un segundo tiempo. Tras confirmar la reducción del trombo (figura 1B), se predilató y se midió la longitud del AC (40 mm) y de la zona de aterrizaje mediante ecografía intravascular (IVUS) (figura 1C). Se implantaron 2 stents coronarios recubiertos PK-Papyrus (SCR) de 5 × 26 mm (Biotronik, Suiza) de proximal a distal. La zona de solapamiento de ambos stents se confirmó mediante StentBoost (Philips Medical Systems, Países Bajos) (figura 1D). El stent se implantó bajo fluoroscopia y en ausencia de movimientos respiratorios. La siguiente angiografía reveló la exclusión incompleta del AC (figura 1E) a pesar de posdilatación con un balón no compliante (BNC) de 5,5 mm. El IVUS confirmó la existencia de un gap entre ambos stents debido al acortamiento de los mismos (E2, figura 1E y vídeo 1 del material adicional). Se implantó otro SCR de 5 × 15 mm y se posdilató...

Seventy-four-year-old male patient admitted with non-ST-elevation acute myocardial infarction. The coronary angiography performed revealed the presence of right coronary artery stenosis with a giant coronary artery aneurysm (CAA) and high thrombus burden (figure 1A). Dual antiplatelet and anticoagulation therapies were recommended for its exclusion in a staged procedure. After confirmation of thrombus reduction (figure 1B), predilatation was attempted and both the length of the CAA (40 mm) and the landing zone were measured on the intravascular ultrasound (IVUS) (figure 1C). From proximal to distal, two 5 mm x 26 mm-PK-Papyrus covered coronary stents (PCS) (Biotronik, Switzerland) were deployed. The overlapping stent zone was confirmed using the StentBoost imaging modality (Philips Medical Systems, Nederland) (figure 1D) and the stent was deployed under fluoroscopic guidance in the absence of any respiratory movements. The subsequent angiography performed revealed an incomplete CAA exclusion (figure 1E) despite postdilatation with a 5.5 mm noncompliant balloon (NCB). The IVUS confirmed the existence of a gap between both stents due to stent shortening (E2, figure 1E and video 1 of the supplementary data). Another 5 mm × 15 mm PCS was deployed followed by postdilatation with a 5.5 mm NCB. Both the angiography and the IVUS confirmed the...

BackgroundWe aimed to compare the performance of the recent CASTLE score to J-CTO, CL and PROGRESS CTO scores in a comprehensive database of percutaneous coronary intervention of chronic total occlusion procedures.MethodsScores were calculated using raw data from 1,342 chronic total occlusion procedures included in REBECO Registry that includes learning and expert operators. Calibration, discrimination and reclassification were evaluated and compared.ResultsMean score values were: CASTLE 1.60±1.10, J-CTO 2.15±1.24, PROGRESS 1.68±0.94 and CL 2.52±1.52 points. The overall percutaneous coronary intervention success rate was 77.8%. Calibration was good for CASTLE and CL, but not for J-CTO or PROGRESS scores. Discrimination: the area under the curve (AUC) of CASTLE (0.633) was significantly higher than PROGRESS (0.557) and similar to J-CTO (0.628) and CL (0.652). Reclassification: CASTLE, as assessed by integrated discrimination improvement, was superior to PROGRESS (integrated discrimination improvement +0.036, pConclusionProcedural percutaneous coronary intervention difficulty is not consistently depicted by available chronic total occlusion scores and is influenced by the characteristics of each chronic total occlusion cohort. In our study population, including expert and learning operators, the CASTLE score had slightly better overall performance along with CL score. However, we found only intermediate performance in the c-statistic predicting chronic total occlusion success among all scores.

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that exists in two forms: the first is a transmembrane protein; the second is a soluble catalytic ectodomain of ACE2. The catalytic ectodomain of ACE2 undergoes shedding by a disintegrin and metalloproteinase domain-containing protein 17 (ADAM17), in which calmodulin mediates the calcium signaling pathway that is involved in ACE2 release, resulting in a soluble catalytic ectodomain of ACE2 that can be measured as soluble ACE2 plasma activity. The shedding of the ACE2 catalytic ectodomain plays a role in cardiac remodeling and endothelial dysfunction and is a predictor of all-cause mortality, including cardiovascular mortality. Moreover, considerable evidence supports that the ACE2 catalytic ectodomain is an essential entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Additionally, endotoxins and the pro-inflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNFα) all enhanced soluble catalytic ectodomain ACE2 shedding from the airway epithelia, suggesting that the shedding of ACE2 may represent a mechanism by which viral entry and infection may be controlled such as some types of betacoronavirus. In this regard, ACE2 plays an important role in inflammation and thrombotic response, and its down-regulation may aggravate COVID-19 via the renin-angiotensin system, including by promoting pathological changes in lung injury. Soluble forms of ACE2 have recently been shown to inhibit SARS-CoV-2 infection. Furthermore, given that vitamin D enhanced the shedding of ACE2, some studies reported that vitamin D treatment is associated with prognosis improvement in COVID-19. This is an updated review on the evidence, clinical, and therapeutic applications of ACE2 for COVID-19.

Mujer de 85 años con angina inestable que presentaba lesiones graves y muy calcificadas en las arterias coronaria derecha proximal (figura 1A, asterisco) y descendente anterior proximal-media (figura 1B, asterisco). Figura 1. Se realizó aterectomía rotacional con el sistema RotaPro (Boston Scientific, EE.UU.) en la coronaria derecha (figura 1C) y se implantó un stent farmacoactivo, con buen resultado (figura 1D) confirmado mediante ecografía intracoronaria (figura 1E). Se obtuvo el consentimiento informado de la paciente. Tras sondar el tronco coronario izquierdo (TCI) se cruzó la guía a la descendente anterior. Se avanzó una oliva de 1,5 mm en modo dynaglide hasta el TCI, momento en que el catéter guía se extubó y se produjo una perforación Ellis-III en el TCI (figura 2A, asterisco; vídeo 1 del material adicional); es posible que una deformación inadvertida de la guía dirigiera la oliva hacia la pared del vaso. La paciente presentó taponamiento cardiaco, que fue tratado con pericardiocentesis. Se implantó un stent recubierto PK-Papyrus (Biotronik, Alemania) de 4 × 15 mm en el TCI sin enjaular la bifurcación (figura 2B). Sin embargo, se mantenía una discreta fuga de contraste (figura 2C, asterisco). Tras posdilatar con balón de 4,5 mm, la perforación quedó sellada (figura 2D; vídeo 2...

Eighty-five-year-old woman with unstable angina with serious and heavily calcified lesions in proximal right coronary arteries (figure 1A, asterisk) and proximal and mid left anterior descending coronary artery (figure 1B, asterisk). Rotational atherectomy was performed in the right coronary artery using the RotaPro system (Boston Scientific, United States) (figure 1C) and a drug-eluting stent was implanted with good results (figure 1D) as confirmed by the intracoronary ultrasound (figure 1E). Informed consent was obtained from the patient. Figure 1. After the catheterization of the left main coronary artery (LMCA) the left anterior descending coronary artery was crossed. A 1.5 mm olive-shaped burr was advanced in the DynaGlide mode towards the LMCA, which is when the guide catheter was extubated and an Ellis type III perforation occurred in the LMCA (figure 2A, asterisk; video 1 of the supplementary data); it is possible that an unnoticed deformation of the guidewire moved the burr towards the vessel wall. The patient showed cardiac tamponade that was treated with pericardiocentesis. A 4 × 15 mm PK-Papyrus covered coronary stent (Biotronik, Germany) was implanted in the LMCA without jailing the bifurcation (figure 2B). However, a discrete leak of contrast still occurred (figure 2C, asterisk). After postdilatation with a 4.5 mm...

Introduction and Objectives: To investigate the incidence and clinical relevance of the presence of mobile echogenic images (MEI) during transesophageal echocardiography (TEE) for monitoring of transcatheter aortic valve implantation (TAVI). Methods: Consecutive patients referred to our center for transfemoral or transapical TAVI were included. The procedure was monitored by three-dimensional (3D) TEE and images were analyzed by two independent experts. In-hospital follow-up was carried out and correlated with imaging findings. Results: A total of 104 patients were included. MEI were visualized in 11 patients during the procedure (11%) and in over 50% of cases were identified as thrombi, however no differences in periprocedural stroke were found in follow-up. Conclusions: Visualization of MEI during 3D TEE monitoring of TAVI is relatively common (11%) and in over 50% of cases they are identified as thrombi. The clinical implications of this finding are uncertain, as despite their frequency, the incidence of clinical stroke in this patient population was no higher. 3D TEE is a useful tool for diagnosis of MEI and can alert the operator to their presence. Resumo: Introdução e objetivos: Investigar a incidência e relevância clínica da presença de imagens ecogénicas móveis (IEM), através de ecocardiografia transesofágica (ETE) durante a implantação valvular aórtica percutânea (TAVI). Métodos: Foram incluídos doentes consecutivos referenciados para o nosso centro para realização de TAVI por via transapical ou transfemoral. Foi realizada a monitorização da ETE 3 D e as imagens foram analisadas por dois peritos individualmente. O seguimento foi realizado no hospital e foi correlacionado com achados de imagem. Resultados: Foram definitivamente incluídos 104 doentes. Durante o procedimento foram visualizadas IEM em 11 pacientes (11%) e,em mais de 50% dos casos, foram identificadas como trombos, não tendo, no entanto, sido encontradas diferenças no seguimento dos doentes. Conclusões: A visualização das IEM através da monitorização por ETE 3 D durante a TAVI é relativamente comum (11%) e, em mais de 50% dos casos, são identificadas como trombos. As implicações clínicas deste achado são incertas, porque apesar da sua frequência não há maior incidência de acidente vascular cerebral clínico nesta população de doentes. A ETE é uma ferramenta útil para o diagnóstico e pode alertar o operador da sua presença. Keywords: Transcatheter aortic valve implantation, Three-dimensional, Aortic stenosis, Transaortic valve, Palavras-chave: Implantação valvular aórtica percutânea, 3 D, Estenose aórtica, Válvula transaórtica

Introduction: A permanent pacemaker is frequently needed after transcatheter aortic valve implantation, but the available data are mainly on the CoreValve system. Objective: To evaluate the need for new permanent pacemaker after implantation of the Edwards Sapien device, as well as related factors. Methods: We included the first 100 patients treated with the Edwards Sapien device at our institution. Of these, 12 had a permanent pacemaker before the procedure, and thus our study population was the remaining 88 patients. Results: A permanent pacemaker was indicated in eight patients (9.1%) during hospitalization or at 30 days. After discharge, another four patients needed a pacemaker (at 42 days and three, 18, and 30 months). Two variables were associated with the need for pacemaker during hospitalization: previous dialysis (13% vs. 1%, p=0.042) and complete right bundle branch block before the procedure (25% vs. 5%, p=0.032). More than one month after the procedure, the characteristics associated with the need for pacemaker were plasma creatinine level (2.5±1.7 vs. 1.3±0.6 mg/dl, p=0.001) and previous myocardial infarction (50% vs. 10%, p=0.013). Conclusion: The rate of pacemaker implantation with the Edwards Sapien device was 9.1%. Right bundle branch block and dialysis were associated with this complication. Resumo: Introdução: A necessidade de um pacemaker permanente após implantação percutânea da válvula aórtica é frequente, embora os dados disponíveis estejam principalmente associados ao sistema CoreValve. Objetivos: O objetivo foi avaliar o índice do novo pacemaker permanente, bem como todos os fatores relacionados, após a implantação do dispositivo Edwards-Sapiens. Métodos: Incluímos os primeiros 100 doentes tratados com o dispositivo Edwards-Sapiens no nosso hospital. Destes, 12 já tinham pacemaker permanente antes do procedimento, pelo que a população do estudo corresponde aos restantes 88 doentes. Resultados: O pacemaker permanente foi indicado em oito doentes (9,1%) durante o internamento ou a 30 dias. Após a alta hospitalar, outros quatro doentes necessitaram de colocar o pacemaker (aos 42 dias e aos três, 18 e 30 meses). Duas variáveis foram relacionadas com a necessidade de colocação de pacemaker durante o internamento: diálise prévia (13 versus 1%, p=0,042) e bloqueio completo do ramo direito antes do procedimento (25 versus 5%, p=0,032). Mais do que um mês após o procedimento, as características, que foram relacionadas com a necessidade de colocação de pacemaker, foram os níveis da creatinina plasmática (2,5±1,7 versus 1,3±0,6 mg/dl, p=0,001) e enfarte do miocárdio prévio (50 versus 10%, p=0,013). Conclusão: A necessidade de colocação de pacemaker após a implantação do dispositivo de Edwards-Sapiens foi de 9,1%. O bloqueio completo do ramo direito e a diálise foram associados a esta complicação. Keywords: Pacemaker, Transcatheter aortic valve implantation, Long term, Palavras-chave: Pacemaker, Implantação valvular aórtica percutânea, Longo prazo

Objective: To analyze long-term survival and predictors of mortality in patients evaluated for transcatheter aortic valve implantation (TAVI) depending on the decision taken by the heart team. Methods: All patients with severe aortic stenosis and high surgical risk evaluated for TAVI between June 2008 and June 2012 were included. Patients were grouped according to the therapeutic strategy decided by the heart team. Mean follow-up was 16.6 months (maximum 55.3). Results: A total of 149 patients were evaluated: 79 were accepted for TAVI, 12 had no current indication for valve replacement and were deferred, 13 were redirected to conventional surgery and 45 received medical treatment. The evaluated patients had a mean age of 83.7 years and a mean EuroSCORE of 19.8±12.3. Median survival free from all-cause death was 34.7 months (95% CI 27.1–42.3) in the TAVI group, 47.4 months (95% CI 0–97.4) in the deferred intervention group, not available in the surgery group and 8.2 months (95% CI 5.6–10.9) in the medical treatment group (log-rank p

Introduction and Objectives: The aim of this study was to analyze the incidence of drug-eluting stent thrombosis (sirolimus or everolimus) in patients with chronic total coronary occlusions (CTO) and to determine its clinical implications and related factors. Methods: Data from the 12-month follow-up of the 207 patients included in the CIBELES trial with CTO were analyzed. Results: Stent thrombosis occurred in three patients, two definite and one probable (overall thrombosis rate: 1.4%). However, there were no cases of death or Q-wave myocardial infarction. In univariate analysis, patients with a higher incidence of stent thrombosis were those in whom the target vessel was the left anterior descending, who had single-vessel disease, were assigned to treatment with sirolimus-eluting stents, and those with smaller minimum luminal diameter immediately after the procedure. In multivariate analysis, the only independent predictor of stent thrombosis was minimal luminal diameter immediately after the procedure. Conclusions: The rate of drug-eluting stent thrombosis in patients with CTO is relatively low (1.4%). The only independent predictor of stent thrombosis in this context was minimal luminal diameter after the procedure and the clinical presentation was in all cases relatively benign. Resumo: Introdução e objetivos: o objetivo do nosso estudo foi analisar a incidência de trombose de stent com eluição de fármaco (sirolimus ou everolimus) em pacientes com oclusões coronárias crónicas e identificar as suas implicações clínicas e fatores relacionados. Métodos: 12 meses de acompanhamento dos 207 pacientes incluídos no ensaio Cibeles com oclusão total coronária crónica. Resultados: a trombose de stent ocorreu em três doentes: duas definitivas e uma provável (taxa global de trombose 1,4%). No entanto, não surgiu nenhum caso de morte ou enfarte do miocárdio com onda Q. Na análise univariada, os doentes com maior incidência de trombose de stent foram aqueles em que o vaso-alvo foi a descendente anterior, os que tinham a doença de um vaso, os que foram considerados para tratamento com stent com sirolimus, e aqueles com diâmetro luminal mínimo menor imediatamente após o procedimento. Na análise multivariada, o único preditor independente de trombose do stent foi o diâmetro luminal mínimo imediatamente após o procedimento. Conclusões: a taxa de trombose de stent farmacológico em pacientes com oclusão coronária crónica foi relativamente baixa (1,4%).O único preditor independente de trombose de stent neste contexto foi o diâmetro luminal mínimo após o procedimento, tendo a apresentação clínica em todos os casos sido relativamente benigna. Keywords: Stent, Thrombosis, Everolimus, Sirolimus, Chronic total coronary occlusion, Palavras-chave: Stent, Trombose, Everolimus, Sirolimus, Oclusão coronária crónica total

Resumo: Neste artigo fazemos referência a um caso de reestenose muito tardia de um stent convencional que, através de duas técnicas de diagnóstico intracoronário, ultrassonografia intravascular (IVUS) e tomografia de coerência ótica (OCT), permite dar a conhecer o seu mecanismo subjacente (neoaterosclerose) e facilita o seu tratamento percutâneo (stent convencional direto intrasent). Aproveitamos também a ocasião para fazer uma breve descrição das vantagens e limitações de ambas as técnicas neste tipo de patologia. Abstract: We report a case of very late bare-metal stent restenosis, in which assessment by two intracoronary imaging techniques (intravascular ultrasound and optical coherence tomography) revealed the underlying mechanism (neoatherosclerosis) and facilitated percutaneous treatment (direct bare-metal stent-in-stent). We also take the opportunity to briefly describe the advantages and limitations of both techniques in this pathology. Palavras-chave: Neoaterosclerose, Intervenção coronária percutânea, Ultrassonografia intravascular, Tomografia de coerência ótica, Keywords: Neoatherosclerosis, Percutaneous coronary intervention, Intravascular ultrasound, Optical coherence tomography

Introduction: In recent years, various specific techniques and materials have been developed for the treatment of coronary chronic total occlusions (CTO). Objective: To evaluate the current situation in the treatment of CTO (techniques and material) in our setting. Methods: We evaluated data on techniques and material used in the CIBELES (ChronIc coronary occlusion treated By EveroLimus Eluting Stent) trial, a randomized comparison of sirolimus- and everolimus-eluting stents in 207 patients with CTO in 13 centers in Spain and Portugal. Results: A radial approach was used in 23% of patients, and retrograde techniques were used in only 5%. A high number of balloons were used (2.2 ± 0.9 per patient). Microcatheters were used in 33% of patients, and post-dilatation balloons in only 25%. The mean number of stents implanted per patient was 2.1 ± 1.0, with a mean total stent length of 49 ± 24 mm. Other devices and techniques used were: Tornus penetration catheter in 4% of patients, rotational atherectomy in 2%, and cutting balloon in 1%. Intracoronary ultrasound was used in only 6% of patients. In 34% of cases, operators used guidewires that were not specifically for CTO. Considerable variability between centers was detected in the use of different techniques, the highest and lowest variability being observed in the use of intracoronary ultrasound and the use of CTO guidewires, respectively. Conclusions: In the CIBELES trial, techniques and devices specifically designed for the treatment of CTO were used in a relatively low proportion of patients. Considerable variability between centers was detected. Resumo: Introdução: Durante os últimos anos foram desenvolvidos materiais e técnicas específicos para o tratamento de oclusões totais crónicas (OTC). Objetivo: Avaliar a situação atual no tratamento de OTC (técnicas e material) na nossa realidade. Métodos: Avaliámos os dados relacionados com as técnicas e material usados no estudo CIBELES (ChronIc coronary occlusion treated By EveroLimus Eluting Stent) que comparou de forma aleatororizada stents eluidores de sirolimus e everolimus em 207 doentes com OTC em 13 centros de Espanha e Portugal. Resultados: A abordagem radial foi usada em 23% dos doentes e as técnicas retrógradas foram usadas em apenas 5%. Foi usado um elevado número de balões (2,2 ± 0,9 por doente). Microcatéteres foram usados em 33% e balões de pós-dilatação apenas em 25% dos doentes. O número médio de stents implantados por doente foi de 2,1 ± 1,0, com um comprimento total médio de 49 ± 24 mm. Outro material foi: tornus 4%, aterectomia rotacional 2% e cutting balloon em 1% dos doentes. Ecografia intra-coronária foi usada em apenas 6% dos doentes. Em 34% dos casos os operadores usaram fios-guia que não eram específicos de OTC. Uma alta variabilidade entre centros foi detetada no uso de diferentes técnicas, sendo a variabilidade observada mais alta e mais baixa no uso de ecografia intra-coronária e no uso de guias de OTC, respetivamente. Conclusões: No estudo CIBELES, técnicas e material especificamente desenvolvidos para o tratamento de OTC foram usados numa proporção relativamente baixa dos doentes. Foi detetada uma alta variabilidade entre centros. Keywords: Coronary stents, Coronary angioplasty, Chronic occlusion, Coronary artery disease, Palavras-chave: Stents coronários, Angioplastia coronária, Oclusões crónicas, Doença coronária

Mitral stenosis (MS) is frequently associated with the development of atrial fibrillation (AF) as a consequence of hemodynamic and inflammatory changes in the left atrium. Both conditions predispose to thrombus formation, with frequent involvement of the left atrial appendage (LAA), and consequent increase in the incidence of systemic thromboembolic events. Percutaneous mitral valvuloplasty (PMV) reduces the risk of thromboembolism in patients with significant mitral stenosis. Percutaneous LAA closure is also associated with a reduction in thromboembolic risk in patients with AF, but there are no data regarding the use of this technique in patients with significant mitral valve disease. We report the case of a 57-year-old-woman with significant MS and permanent AF, in New York Heart Association functional class II, who despite adequate oral anticoagulation with acenocoumarol, presented several clinical episodes of systemic thromboembolism in the last four years. It was decided to perform a combined percutaneous procedure, including both PMV and percutaneous LAA closure with the Amplatzer Cardiac Plug device. No significant acute complications occurred and the patient was discharged on indefinite treatment with acenocoumarol associated with aspirin 100 mg/d for three months. After a one-year follow-up, there have been no new embolic episodes or other complications. Resumo: A estenose mitral (EM) é frequentemente associada ao desenvolvimento de fibrilhação auricular (FA) como consequência de alterações hemodinâmicas e inflamatórias na aurícula esquerda. Ambas as condições predispõem à formação de trombos, com frequente envolvimento do apêndice auricular, e consequente aumento da incidência de eventos tromboembólicos sistémicos. A valvuloplastia mitral percutânea (VMP) reduz o risco de tromboembolismo em doentes com EM significativa. O encerramento percutâneo do apêndice auricular esquerdo (PCLAA) na FA também está associado a uma redução de risco de tromboembolismo em pacientes com FA, mas não existem dados sobre a utilização desta técnica em doentes com MS. Relatamos o caso de uma mulher de 57 anos de idade com significativa EM e FA permanente, em classe funcional II, que, apesar de anticoagulação oral adequada com acenocumarol, apresentou nos últimos quatro anos vários episódios clínicos de tromboembolismo sistémico. Foi decidido realizar um procedimento percutâneo combinado de PMV e PCLAA com dispositivo Amplatzer Cardiac Plug. Não se verificaram complicações agudas significativas e o paciente recebeu alta com acenocumarol de forma indefinida, associado com aspirina 100 mg/d durante três meses. Depois de um ano de follow-up, não houve novos episódios embólicos ou outras complicações. Keywords: Percutaneous left atrial appendage closure, Percutaneous mitral valvuloplasty, Mitral stenosis, Atrial fibrillation, Palavras-chave: Encerramento percutâneo do apêndice arterial esquerdo, Valvuloplastia mitral percutânea, Estenose mitral, Fibrilhação auricular

Background: Percutaneous septal ablation by alcohol-induced septal branch occlusion was introduced as a new treatment option in symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). Our aim was to evaluate procedural and long-term clinical and echocardiographic outcomes in patients with HOCM treated by alcohol septal ablation (ASA) at our center. Methods: This single-center retrospective study included 14 consecutive HOCM patients undergoing percutaneous ASA (66.4 ± 12.1 years, 71.4% female). At baseline all patients presented persistent symptoms despite optimized medical treatment, left ventricular outflow tract (LVOT) obstruction with a peak gradient >50 mmHg, systolic anterior motion of the mitral valve, and ventricular septal thickness ≥15 mm. ASA was considered successful when the LVOT pressure gradient fell to less than 50% of baseline value. All patients had echocardiographic evaluation at baseline, intraprocedure and at follow-up, and a long-term clinical follow-up (25 ± 38 months) with evaluation of functional class and occurrence of symptoms or cardiovascular events. Results: Percutaneous ASA achieved a 71.4% acute and 85.7% long-term success rate. Peak LVOT gradient decreased from 104 ± 40 mmHg at baseline to 58 ± 30 mmHg intraprocedure (p = 0.03) and 35 ± 26 mmHg at follow-up (p = 0.001); total gradient decrease was 75 ± 43 mmHg. Ventricular septal thickness and mitral regurgitation also presented significant decreases during follow-up (from 24 ± 5 mm to 18 ± 4 mm, p = 0.02, and from grade 2.4 ± 0.6 to 1.4 ± 0.5, p 50 mmHg, movimento sistólico anterior da válvula mitral e espessura do septo interventricular ≥15 mm. A ASA foi considerada bem sucedida quando o gradiente do LVOT diminuiu para menos de 50% do valor inicial. Todos os doentes foram submetidos a avaliação clínica e ecocardiográfica basal, intraprocedimento e durante o seguimento, com avaliação da classe funcional e ocorrência de sintomas ou eventos cardiovasculares a longo-prazo (25 ± 38 meses). Resultados: A ASA percutânea obteve uma taxa de sucesso de 71,4% e 85,7%, respetivamente aguda e a longo-prazo. O gradiente máximo do LVOT diminuiu de 104 ± 40 mmHg basais para 58 ± 30 mmHg intraprocedimento (p = 0,03) e 35 ± 26 mmHg a longo-prazo (p = 0,001); o decréscimo total do gradiente foi de 75 ± 43 mmHg. Também a espessura do septo interventricular e a regurgitação mitral apresentaram uma diminuição significativa durante o seguimento (de 24 ± 5 mm para 18 ± 4 mm, p = 0,02, e de grau 2,4 ± 0,6 para 1,4 ± 0,5, p

Clinical trials have shown that functional assessment of coronary stenosis by fractional flow reserve (FFR) improves clinical outcomes. Intravascular ultrasound (IVUS) complements conventional angiography, and is a powerful tool to assess atherosclerotic plaques and to guide percutaneous coronary intervention (PCI). Computational fluid dynamics (CFD) simulation represents a novel method for the functional assessment of coronary flow. A CFD simulation can be calculated from the data normally acquired by IVUS images. A case of coronary heart disease studied with FFR and IVUS, before and after PCI, is presented. A three-dimensional model was constructed based on IVUS images, to which CFD was applied. A discussion of the literature concerning the clinical utility of CFD simulation is provided. Resumo: Estudos clínicos demonstraram que a avaliação funcional da doença coronária com fio de pressão e determinação da reserva fracionada de fluxo (fractional flow reserve - FFR) melhora a evolução clínica. O estudo por ultra-som intravascular (IVUS) complementa a angiografia convencional, e é uma ferramenta poderosa para a avaliação das placas ateroscleróticas orientando a intervenção coronária percutânea (ICP). A simulação computorizada da dinâmica de fluidos (CFD), representa um novo método que permite avaliar funcionalmente o fluxo coronário. A CFD pode ser calculada a partir dos dados normalmente obtidos por IVUS. É apresentado um caso de doença coronária estudada com FFR e IVUS, antes e após a ICP. Foi construído um modelo tridimensional com base nas imagens obtidas por IVUS e avaliado com a técnica de CFD. É apresentada uma discussão bibliográfica sobre a utilidade clínica da simulação com CFD. Keywords: Coronary artery disease, Myocardial fractional flow reserve, Intravascular ultrasound, Fluid dynamics, Computer simulation, Palavras-chave: Doença cardíaca coronária, Reserva fracionada de fluxo miocárdico, Ultra-sonografia intravascular, Dinâmica de fluidos, Simulação computorizada