Fatores de risco para embolia pulmonar em pacientes com COVID-19 anticoagulados na unidade de terapia intensiva submetidos à angiografia por tomografia computadorizada / Pulmonary embolism risk factors for intensive care unit anticoagulated COVID-19 patients undergoing computed tomography angiography

RESUMO Objetivo: Avaliar a incidência de embolia pulmonar, seu relacionamento com os níveis de dímero D e outros possíveis fatores associados, além dos efeitos adversos da anticoagulação e meios de contraste. Métodos: Conduziu-se um estudo de coorte retrospectiva em um hospital público chileno. Foram incluídos os pacientes com idade acima de 18 anos com COVID-19, mecanicamente ventilados na unidade de terapia intensiva, admitidos entre março e junho de 2020. Todos os pacientes receberam tromboprofilaxia com heparina, que foi aumentada até uma dose de anticoagulação com níveis de dímero D acima de 3µg/mL. Resultados: Foram acompanhados 127 pacientes, dos quais 73 foram submetidos à angiografia por tomografia computadorizada (média de idade de 54 ± 12 anos; 49 homens). Sessenta e dois dos 73 pacientes (84,9%) receberam anticoagulação total antes da angiografia por tomografia computadorizada. Além disso, 18 dos 73 pacientes tiveram embolia pulmonar (24,7%). Na comparação entre pacientes com e sem embolia pulmonar, não se observaram diferenças significantes em termos de idade, sexo, obesidade, tabagismo, escores de Wells e Genebra revisado, dímero D ou mortalidade. O uso de anticoagulantes foi similar em ambos os grupos. O número de dias desde o início da anticoagulação até a angiografia por tomografia computadorizada foi significantemente menor no grupo com embolia pulmonar (p = 0,002). Três pacientes tiveram lesão renal aguda após o contraste (4,1%), e um paciente teve sangramento importante. Conclusão: Apesar da anticoagulação, um em cada quatro pacientes com COVID-19 submetidos à ventilação mecânica e avaliados com angiografia por tomografia computadorizada apresentou embolia pulmonar. Com uma maior demora para realização da angiografia por tomografia computadorizada após início de anticoagulação empírica, identificou-se um número significantemente menor de embolias

Abstract Objective: To assess pulmonary embolism incidence, its relationship with D-dimer levels and other possible associated factors in addition to anticoagulation and contrast medium adverse effects. Methods: A retrospective observational cohort study at a Chilean public hospital was performed. Intensive care unit mechanically ventilated COVID-19 patients older than 18 years old between March and June 2020 were included. All patients received heparin thromboprophylaxis, which was increased to the anticoagulation dose with D-dimer greater than 3µg/mL. Results: A total of 127 patients were followed up, of whom 73 underwent pulmonary computed tomography angiography (mean age, 54 ± 12 years; 49 men). Sixty-two of the 73 patients (84.9%) received full anticoagulation before computed tomography angiography. In addition, 18 of the 73 patients had pulmonary embolism (24.7%). When comparing patients with and without pulmonary embolism, no significant differences were observed in age, sex, obesity, smoking, Wells and revised Geneva scores, D-dimer or mortality. Anticoagulant use was similar in both groups. Days from the start of anticoagulation until computed tomography angiography were significantly lower in the pulmonary embolism group (p = 0.002). Three patients presented post contrast-acute kidney injury (4.1%), and one patient had major bleeding. Conclusion: Despite anticoagulation, one in four COVID-19 patients connected to mechanical ventilation and evaluated with pulmonary computed tomography angiography had pulmonary embolism. With a longer the delay in performing computed tomography angiography once empirical anticoagulation was started, significantly less pulmonary embolism was identified.

Enfermedad de Kawasaki: ¿una entidad exclusiva de niños? / Kawasaki disease, is it exclusive of children?

Resumen La enfermedad de Kawasaki es un síndrome febril agudo y autolimitado, de presunta etiología autoinmune, que característicamente afecta a niños menores de 5 años. Esta enfermedad consiste en una vasculitis aguda de pequeños y medianos vasos que favorece la formación de aneurismas en las arterias coronarias. El diagnóstico en la fase aguda es esencialmente clínico, mientras que en la fase crónica suele hacerse al documentar las secuelas vasculares. La importancia de la identificación apropiada de esta enfermedad radica en que muchos de los infartos fatales y no fatales en personas menores de 40 años tienen hallazgos compatibles con este diagnóstico. Se presenta el caso de un adulto joven con dolor torácico y angiotomografía coronaria con hallazgos compatibles con secuelas de enfermedad de Kawasaki del adulto.

Abstract Kawasaki disease is an acute and self-limited febrile syndrome with a presumed autoimmune etiology that characteristically affects children under 5 years of age. Kawasaki disease is an acute vasculitis of small and medium vessels that facilitates the formation of coronary aneurysms. The diagnosis of the disease during the acute phase is essentially clinical, while the diagnosis of Kawasaki disease during the chronic phase is performed when the vascular complications are detected. The importance of proper identification of Kawasaki disease lies in the fact that many of the fatal and non-fatal infarcts in young adults (<40 years) have findings compatible with this diagnosis. This article describes the case of a young patient with chest pain and coronary angiotomography showing sequelae of Kawasaki disease in the adult.

Menor Prevalência e Extensão da Aterosclerose Coronária na Doença de Chagas Crônica por Angiotomografia Coronária / Lower Prevalence and Severity of Coronary Atherosclerosis in Chronic Chagas' Disease by Coronary Computed Tomography Angiography

Resumo Fundamento Em regiões endêmicas da doença de Chagas, por muitos anos, existe uma observação empírica recorrente de que a doença arterial coronariana (DAC) é incomum em pacientes com doença de Chagas. Estudos anteriores baseados em análise patológica ou angiografia coronária invasiva apresentam resultados controversos. Objetivo Investigar se a DAC é menos prevalente e menos grave em pacientes com doença de Chagas crônica em comparação a uma população pareada controle, com perfil de risco para DAC similar. Métodos Um total de 86 participantes, 43 pacientes com doença de Chagas crônica consecutivos e 43 indivíduos assintomáticos, sem qualquer história prévia de doença cardíaca ou doença DAC conhecida (grupo controle), foram incluídos no estudo. Pacientes e controles foram pareados quanto sexo, idade e escore de risco de Framingham. Todos os pacientes foram analisados quanto ao escore de cálcio coronário (ECC) e submetidos à angiotomografia coronária usando um tomógrafo de 320 detectores. O nível de significância estatística adotado foi de p < 0,05. Resultados O ECC foi significativamente mais baixo em pacientes com doença de Chagas em comparação aos controles (p<0,05). A presença de placas ateroscleróticas coronárias foi significativamente menos frequente em pacientes com doença de Chagas que nos controles (20,9% versus 41,9%, p=0,037). Após ajuste quanto ao escore de Framingham, o odds ratio para a presença de qualquer calcificação coronária foi de 0,26 (IC95%: 0,07-0,99, p=0,048). O padrão é similar para escore de cálcio coronário (ECC) > 10 (OR: 0,11, IC95%: 0,01-0,87, p=0,04), e para a presença de estenose (OR: 0,06, IC95%: 0,01-0,47, p=0,001). O pareamento por escore de propensão também mostrou um efeito da doença de Chagas no ECC (-21,6 pontos no escore absoluto e 25% menos pacientes com ECC > 10; p=0,015). Conclusões A prevalência e a gravidade da DAC são mais baixas nos pacientes com doença de Chagas crônica em comparação a uma população pareada e perfil de risco para DAC similar. (Arq Bras Cardiol. 2020; 115(6):1051-1060)

Abstract Background In Chagas' disease endemic regions, there has been for many years a recurrent empirical observation that coronary artery disease (CAD) is uncommon in patients with Chagas' disease. Previous pathological and invasive coronary angiography studies led to controversial results. Objective We sought to investigate whether CAD is less prevalent and less severe in patients with chronic Chagas' disease when compared with a matched population with a similar CAD risk profile. Methods A total of 86 participants, 43 consecutive patients with chronic Chagas' disease and 43 asymptomatic individuals, without any prior history of cardiac disease or known CAD (control group), were included. Patients and controls were matched according to gender, age, and Framingham risk score. All participants underwent coronary calcium scoring and coronary computed tomography angiography on a 320-row detector scanner. Statistical significance level adopted was p < 0.05. Results The coronary artery calcium score (CACS) was significantly lower in patients with Chagas' disease than in controls (p<0.05). The presence of coronary atherosclerotic plaques was significantly less frequent in patients with Chagas' disease than in controls (20.9% versus 41.9%, p=0.037). After adjustment for the Framingham score, the odds ratio for the presence of any coronary artery calcium (CAC) in Chagas patients was 0.26 (95%CI: 0.07-0.99, p=0.048). The pattern is similar for CACS > 10 (OR: 0.11, 95%CI: 0.01-0.87, p=0.04) and for the presence of any stenosis (OR: 0.06, 95%CI: 0.01-0.47, p=0.001). Propensity score matching also indicated an effect of Chagas disease on the CACS (-21.6 points in the absolute score and 25% less of patients with CACS >10, p=0.015). Conclusions CAD is less prevalent and less severe in patients with chronic Chagas' disease when compared with a matched population with a similar CAD risk profile. (Arq Bras Cardiol. 2020; 115(6):1051-1060)

Vasculitis del tronco celíaco como presentación de arteritis de Takayasu / Vasculitis of the celiac artery as a presentation of Takayasu's arteritis

La arteritis de Takayasu es una vasculitis idiopática y granulomatosa crónica que se manifiesta en forma de panaortitis, de etiología desconocida, aunque se postula un origen autoinmune. Es progresiva y genera, tanto en adultos como en niños, estenosis segmentaria, oclusión, dilatación y/o aneurismas. La vasculitis aislada gastrointestinal sin afectación sistémica es rara. Este caso lleva a tener en cuenta la manifestación abdominal atípica de la arteritis de Takayasu en el diagnóstico diferencial de un síntoma frecuente, como la epigastralgia, y a destacar el rol que ocupan en la actualidad los métodos de imágenes no invasivos para su diagnóstico.

Takayasu arteritis is an idiopathic and chronic granulomatous vasculitis manifested in the form of panaortitis, of unknown etiology, even though an autoimmune origin is postulated. It is progressive and generates, in adults and children, segmental stenosis, occlusion, dilation and / or aneurysms. Isolated gastrointestinal vasculitis without systemic involvement is rare. This case leads us to take into account the atypical abdominal manifestation of Takayasu arteritis in the differential diagnosis of a frequent symptom, such as epigastralgia, and to highlight the role currently played by non-invasive imaging methods for its diagnosis.

Patency of individual and sequential coronary artery bypass in patients with ischemic heart disease: a meta-analysis

Abstract Objective: To evaluate the patency of individual and sequential coronary artery bypass in patients with ischemic heart disease. Methods: We searched PubMed, Cochrane Library, Excerpta Medica Database, and ClinicalTrials.gov databases for controlled trials. Endpoints included graft patency, anastomosis patency, occluded rates in left anterior descending (LAD) system and right coronary artery (RCA) system, in-hospital mortality, and follow-up mortality. Pooled risk ratios (RRs) and standardized mean difference (SMD) were used to assess the relative data. Results: Nine cohorts, including 7100 patients and 1440 grafts under individual or sequential coronary artery bypass. There were no significant differences between individual and sequential coronary artery bypass in the graft patency (RR=0.96; 95% CI=0.91-1.02; P=0.16; I2=87%), anastomosis patency (RR=0.95; 95% CI=0.91-1.00; P=0.05; I2=70%), occluded rate in LAD system (RR=1.03; 95% CI=0.92-1.16; P=0.58; I2=37%), occluded rate in RCA system (RR=1.36; 95% CI=0.72-2.57; P=0.35; I2=95%), in-hospital mortality (RR=1.57; 95% CI=0.92-2.69; P=0.10; I2=0%), and follow-up mortality (RR=0.96; 95% CI=0.36-2.53; P=0.93; I2=0%). Conclusion: No significant differences on clinical data were observed regarding anastomosis patency, occluded rate in LAD system, occluded rate in RCA system, in-hospital mortality, and follow-up mortality, indicating that the patency of individual and the patency of sequential coronary artery bypass are similar to each other.

The bridge occlusion balloon for venous angioplasty in superior vena cava occlusion

Abstract The Bridge Occlusion Balloon is a compliant balloon, specifically designed for temporary Superior vena cava occlusion in case of Superior Vena Cava laceration during lead extraction procedures. We here report the first case, using Bridge Occlusion Ballon for a venous angioplasty in a patient with dysfunctional pacemaker leads and symptomatic Superior Vena Cava occlusion. After successful lead extraction, venography was showing a narrow venous canal. Therefore, venous angioplasty using the Bridge balloon was performed. Especially for high-risk lead extraction cases in patients with Superior Vena Cava stenosis, the Bridge Occlusion Ballon might be used as a combination of a safety-net in case of Superior Vena Cava perforation and for Superior Vena Cava angioplasty.

Surgical aspects of no-touch saphenous vein graft harvesting in cabg: clinical and angiographic follow-up at 3 months

Abstract With more than 800,000 coronary artery bypass grafting (CABG) operations annually worldwide and the saphenous vein being the most common conduit used, there is no question that improving saphenous vein graft patency is one of the most important tasks in CABG. This video describes the no-touch harvesting procedure of the saphenous vein on an 80-year old man with hypertension, hyperlipidemia and a previous myocardial infarction with percutaneous coronary intervention to the right coronary artery. He was complaining of exertional chest pain and was diagnosed with stable angina pectoris. The coronary angiography showed advanced three vessel disease with significant stenoses in the left anterior descending (LAD) artery, two marginal arteries (MAs) and the posterior descending artery (PDA), in addition to an occluded diagonal artery (DA). The patient received a triple sequential no-touch vein graft to the PDA and two MAs together with a double sequential no-touch vein graft to the DA and LAD. A vein graft was used to bypass the LAD due to the age of the patient and the low degree of stenosis in the LAD. The no-touch harvesting technique is described in detail in the film with complete narration. A follow-up of this patient was performed at three months both clinically and with a computed tomography angiography (CTA). No angina pectoris symptoms were reported by the patient and the wounds in the chest and lower limb were completely healed. The CTA showed patent no-touch saphenous vein grafts to all the distal anastomoses.

Pulmonary arteriovenous malformations: diagnostic and treatment characteristics / Malformações arteriovenosas pulmonares: características diagnósticas e de tratamento

ABSTRACT Objective: To present a case series of pulmonary arteriovenous malformations (PAVMs), describing the main clinical findings, the number/location of pulmonary vascular abnormalities, the clinical complications, and the treatment administered. Methods: This was a retrospective observational study evaluating patients with PAVM divided into two groups: hereditary hemorrhagic telangiectasia (HHT); and idiopathic PAVM (iPAVM). Results: A total of 41 patients were selected for inclusion, but only 33 had PAVMs. After clinical evaluation, 27 and 6 were diagnosed with HHT and iPAVM, respectively. In the HHT group, the mean age was 49.6 years and 88.9% were female. In that group, 4 patients had an SpO2 of < 90% and the most common clinical finding was epistaxis. In the iPAVM group, the mean age was 48.1 years and 83.3% were female. In that group, 3 patients had an SpO2 of < 90%. Computed tomographic pulmonary angiography showed that most of the PAVMs were in the lower lobes: 56.4% in the HHT group and 85.7% in the iPAVM group. Embolization was performed in 23 patients (in both groups). At this writing, 10 patients are scheduled to undergo the procedure. One of the patients who underwent embolization was subsequently referred for pulmonary resection. Conclusions: In both of the PAVM groups, there was a predominance of women and of fistulas located in the lower lobes. Few of the patients had respiratory symptoms, and most had an SpO2 > 90%. The treatment chosen for all patients was percutaneous transcatheter embolization.

RESUMO Objetivo: Apresentar uma série de casos de malformações arteriovenosas pulmonares (MAVP) e descrever os principais achados clínicos, a quantidade e localização das MAVP, as complicações clínicas e os tratamentos realizados. Métodos: Estudo retrospectivo observacional que avaliou pacientes com MAVP divididos em dois grupos: telangiectasia hemorrágica hereditária (THH) e MAVP idiopática (MAVPi). Resultados: Foram avaliados 41 pacientes, sendo 33 pacientes portadores de MAVP. Após a avaliação clínica, 27 e 6 foram diagnosticados com THH e MAVPi, respectivamente. No grupo THH a média de idade foi de 49,6 anos e 88,9% eram do sexo feminino. Desses pacientes, 4 tinham SpO2 < 90% e o achado clínico mais frequente era epistaxe. No grupo MAVPi a média de idade foi de 48,1 anos, sendo que 83,3% eram do sexo feminino. Desses, 3 tinham SpO2 < 90%. Após a realização de angiotomografia de tórax observou-se que a maior parte das MAVP se situava nos lobos inferiores, totalizando 56,4% e 85,7% nos grupos THH e MAVPi, respectivamente. O tratamento por embolização foi realizado em 23 pacientes nos dois grupos, enquanto 10 aguardavam o procedimento até o momento da escrita deste estudo. Um paciente submetido à embolização foi encaminhado para ressecção pulmonar. Conclusões: Em ambos os grupos de pacientes com MAVP observou-se uma predominância de mulheres e de fístulas localizadas nos lobos inferiores. A maioria era assintomático respiratório com SpO2 > 90%. O tratamento de escolha para todos foi a embolização percutânea por cateter.

Use of 3d printing in preoperative planning and training for aortic endovascular repair and aortic valve disease

Abstract Introduction: Three-dimensional (3D) printing has become an affordable tool for assisting heart surgeons in the aorta endovascular field, both in surgical planning, education and training of residents and students. This technique permits the construction of physical prototypes from conventional medical images by converting the anatomical information into computer aided design (CAD) files. Objective: To present the 3D printing feature on developing prototypes leading to improved aortic endovascular surgical planning, as well as transcatheter aortic valve implantation, and mainly enabling training of the surgical procedure to be performed on patient's specific condition. Methods: Six 3D printed real scale prototypes were built representing different aortic diseases, taken from real patients, to simulate the correction of the disease with endoprosthesis deployment. Results: In the hybrid room, the 3D prototypes were examined under fluoroscopy, making it possible to obtain images that clearly delimited the walls of the aorta and its details. The endovascular simulation was then able to be performed, by correctly positioning the endoprosthesis, followed by its deployment. Conclusion: The 3D printing allowed the construction of aortic diseases realistic prototypes, offering a 3D view from the two-dimensional image of computed tomography (CT) angiography, allowing better surgical planning and surgeon training in the specific case beforehand.

Atherosclerotic Plaque in Patients with Zero Calcium Score at Coronary Computed Tomography Angiography / Placa Aterosclerótica à Angiotomografia de Coronárias em Pacientes com Escore de Cálcio Zero

Abstract Background: In view of the high mortality for cardiovascular diseases, it has become necessary to stratify the main risk factors and to choose the correct diagnostic modality. Studies have demonstrated that a zero calcium score (CS) is characteristic of a low risk for cardiovascular events. However, the prevalence of individuals with coronary atherosclerotic plaques and zero CS is conflicting in the specialized literature. Objective: To evaluate the frequency of patients with coronary atherosclerotic plaques, their degree of obstruction and associated factors in patients with zero CS and indication for coronary computed tomography angiography (CCTA). Methods: This is a cross-sectional, prospective study with 367 volunteers with zero CS at CCTA in four diagnostic imaging centers in the period from 2011 to 2016. A significance level of 5% and 95% confidence interval were adopted. Results: The frequency of atherosclerotic plaque in the coronary arteries in 367 patients with zero CS was 9.3% (34 individuals). In this subgroup, mean age was 52 ± 10 years, 18 (52.9%) were women and 16 (47%) had significant coronary obstructions (> 50%), with involvement of two or more segments in 4 (25%) patients. The frequency of non-obese individuals (90.6% vs 73.9%, p = 0.037) and alcohol drinkers (55.9% vs 34.8%, p = 0.015) was significantly higher in patients with atherosclerotic plaques, with an odds ratio of 3.4 for each of this variable. Conclusions: The frequency of atherosclerotic plaque with zero CS was relatively high, indicating that the absence of calcification does not exclude the presence of plaques, many of which obstructive, especially in non-obese subjects and alcohol drinkers.

Resumo Fundamento: Diante da alta mortalidade por doenças cardiovasculares, faz-se necessária a estratificação dos principais fatores de riscos e escolha correta da modalidade diagnóstica. Estudos demonstraram que escore de cálcio (EC) zero caracteriza baixo risco de eventos cardiovasculares. No entanto, a frequência de portadores de placa aterosclerótica coronária com EC zero é conflitante na literatura especializada. Objetivo: Avaliar a frequência de pacientes com placa aterosclerótica coronária, seu grau de obstrução e fatores associados em pacientes com EC zero e indicação para angiotomografia computadorizada de coronárias (ATCC). Métodos: Trata-se de estudo transversal, prospectivo, com 367 voluntários portadores de EC zero, mediante a ATCC, no período de 2011-16, em quatro centros de diagnóstico por imagem. Foi assumido nível de significância 5% e intervalo de confiança de 95%. Resultados: A frequência de placa aterosclerótica nas artérias coronárias dos 367 pacientes com EC zero foi de 9,3% (34 indivíduos); neste subgrupo, a média de idade foi 52 ± 10 anos, 18 (52,9%) eram mulheres e 16 (47%) exibiam obstruções coronarianas significativas (> 50%), dos quais 4 (25%) apresentaram placas em pelo menos dois segmentos. A frequência de não obesos (90,6% vs. 73,9%; p = 0,037) e de etilistas (55,9% vs. 34,8%; p = 0,015) foi significativamente maior nos portadores de placa, apresentando, cada variável, odds ratio de 3,4 para o desenvolvimento das referidas placas. Conclusões: A frequência de placa aterosclerótica com EC zero foi considerável, evidenciando, portanto, que a ausência de calcificação não exclui placa, muitas das quais obstrutivas, principalmente nos não obesos e etilistas.

Thyrotropin and free thyroxine levels and coronary artery disease: cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Data on the association between subclinical thyroid dysfunction and coronary artery disease (CAD) is scarce. We aimed to analyze the association between thyroid function and CAD using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). We included subjects with normal thyroid function (0.4-4.0 mIU/L, and normal free thyroxine, FT4, or 0.8 to 1.9 ng/dL), subclinical hypothyroidism (SCHypo; TSH>4.0 mIU/L and normal FT4), and subclinical hyperthyroidism (SCHyper; TSH<0.4 mIU/L and normal FT4) evaluated by coronary computed tomography angiography. We excluded individuals using medications that interfere in thyroid function or with past medical history of cardiovascular disease. Logistic regression models evaluated the presence of CAD, segment involvement score (SIS) >4, and segment severity score (SSS) >4 of coronary arteries as the dependent variables, and quintiles of TSH and FT4 as the independent variables, adjusted for demographical data and cardiovascular risk factors. We included 767 subjects, median age 58 years (IQR=55-63), 378 (49.3%) women, 697 euthyroid (90.9%), 57 (7.4%) with SCHypo, and 13 (1.7%) with SCHyper. No association between TSH and FT4 quintiles and CAD prevalence was noted. Similarly, no association between TSH levels and the extent or severity of CAD, represented by SIS>4 and SSS>4 were seen. Restricting analysis to euthyroid subjects did not alter the results. TSH levels were not significantly associated with the presence, extent, or severity of CAD in a middle-aged healthy population.

Hybrid approach of aortic diseases: zone 1 delivery and volumetric analysis on the descending aorta

Abstract Introduction: Conventional techniques of surgical correction of arch and descending aortic diseases remains as high-risk procedures. Endovascular treatments of abdominal and descending thoracic aorta have lower surgical risk. Evolution of both techniques - open debranching of the arch and endovascular approach of the descending aorta - may extend a less invasive endovascular treatment for a more extensive disease with necessity of proximal landing zone in the arch. Objective: To evaluate descending thoracic aortic remodeling by means of volumetric analysis after hybrid approach of aortic arch debranching and stenting the descending aorta. Methods: Retrospective review of seven consecutive patients treated between September 2014 and August 2016 for diseases of proximal descending aorta (aneurysms and dissections) by hybrid approach to deliver the endograft at zone 1. Computed tomography angiography were analyzed using a specific software to calculate descending thoracic aorta volumes pre- and postoperatively. Results: Follow-up was done in 100% of patients with a median time of 321 days (range, 41-625 days). No deaths or permanent neurological complications were observed. There were no endoleaks or stent migrations. Freedom from reintervention was 100% at 300 days and 66% at 600 days. Median volume reduction was of 45.5 cm3, representing a median volume shrinkage by 9.3%. Conclusion: Hybrid approach of arch and descending thoracic aorta diseases is feasible and leads to a favorable aortic remodeling with significant volume reduction.

Influence of the tilt angle of Percutaneous Aortic Prosthesis on Velocity and Shear Stress Fields / Influência do Ângulo de Inclinação da Prótese Percutânea Aórtica no Campo de Velocidade e Estresse de Cisalhamento

Abstract Background: Due to the nature of the percutaneous prosthesis deployment process, a variation in its final position is expected. Prosthetic valve placement will define the spatial location of its effective orifice in relation to the aortic annulus. The blood flow pattern in the ascending aorta is related to the aortic remodeling process, and depends on the spatial location of the effective orifice. The hemodynamic effect of small variations in the angle of inclination of the effective orifice has not been studied in detail. Objective: To implement an in vitro simulation to characterize the hydrodynamic blood flow pattern associated with small variations in the effective orifice inclination. Methods: A three-dimensional aortic phantom was constructed, reproducing the anatomy of one patient submitted to percutaneous aortic valve implantation. Flow analysis was performed by use of the Particle Image Velocimetry technique. The flow pattern in the ascending aorta was characterized for six flow rate levels. In addition, six angles of inclination of the effective orifice were assessed. Results: The effective orifice at the -4° and -2° angles directed the main flow towards the anterior wall of the aortic model, inducing asymmetric and high shear stress in that region. However, the effective orifice at the +3° and +5° angles mimics the physiological pattern, centralizing the main flow and promoting a symmetric distribution of shear stress. Conclusion: The measurements performed suggest that small changes in the angle of inclination of the percutaneous prosthesis aid in the generation of a physiological hemodynamic pattern, and can contribute to reduce aortic remodeling.

Resumo Fundamento: Devido à natureza do processo de liberação da prótese percutânea, é esperada uma variabilidade do posicionamento final da válvula. A localização da prótese irá definir a posição espacial do seu orifício efetivo em relação ao ânulo aórtico. O padrão do fluxo sanguíneo em aorta ascendente está relacionado ao processo de remodelamento aórtico, além de ser dependente da disposição espacial do orifício efetivo. O efeito hemodinâmico de pequenas variações na angulação do orifício efetivo ainda não foi estudado em detalhes. Objetivo: O objetivo do presente trabalho foi implementar uma simulação in vitro do fluxo sanguíneo para caracterização do padrão hidrodinâmico, associado a pequenas variações na inclinação do orifício efetivo. Métodos: Para esse fim, foi construído um fantoma aórtico tridimensional, que reproduziu a anatomia de um paciente submetido ao implante valvar percutâneo. A análise de fluxo foi realizada através da técnica de Velocimetria por Imagens de Partícula. O padrão de escoamento em aorta ascendente foi caracterizado para seis níveis de vazão de fluxo. Além disso, foram estudados seis inclinações do orifício efetivo. Resultados: O estudo demonstrou que o orifício efetivo nos ângulos -4° e -2° direcionaram o fluxo principal para a parede anterior do modelo aórtico, induzindo um cisalhamento assimétrico e elevado nessa região. Por outro lado, os ângulos +3° e +5° mimetizam o padrão fisiológico, centralizando o fluxo principal e promovendo uma distribuição simétrica do cisalhamento. Conclusão: As medições realizadas sugerem que pequenas alterações angulares na prótese percutânea auxiliam na geração de um padrão hemodinâmico fisiológico, podendo contribuir para menor remodelamento aórtico.