Surgical treatment of heart failure in China: towards the era of artificial heart / 中华外科杂志

The number of patients with heart failure in China is large, and the proportion of patients with end-stage heart failure continues to increase. The clinical effect of guideline-directed medications therapy for end-stage heart failure is poor. Heart transplantation is the most effective treatment for end-stage heart failure. But it is faced with many limitations such as the shortage of donors. In recent years, the research and development of artificial heart in China has made great progress. Three devices have been approved by the National Medical Products Administration for marketing, and another one is undergoing pre-marketing clinical trial. Since 2017, more than 200 cases of ventricular assist device implantation have been carried out in more than 34 hospitals in China. Among them, 70 patients in Fuwai Hospital, Chinese Academy of Medical Sciences had a 2-year survival rate of 90%. The first patient has survived more than 5 years with the device. More efforts should be put into the training of standardized technical team and quality control. Further research should be carried out in the aspects of pulsatile blood flow pump, fully implanted cable-free device, and improved biomaterial with better blood compatibility.

Uterine Artery Pulsatility Index as a Pre-eclampsia Predictor in the 3 Trimesters in Women with Singleton Pregnancies / Índice de pulsatilidade da artéria uterina como preditor de pré-eclâmpsia nos 3 trimestres em mulheres com gestações únicas

Abstract Objective To evaluate the mean uterine artery pulsatility index (UtAPI) in each trimester of pregnancy as a predictor of early or late pre-eclampsia (PE) in Colombian pregnant women. Methods The UtAPI was measured in singleton pregnancies in each trimester. Uterine artery pulsatility index as predictor of PE was evaluated by odds ratio (OR), receiver operating characteristic (ROC) curves, and Kaplan-Meier diagram. Results Analysis in the 1st and 3rd trimester showed that abnormal UtAPI was associated with early PE (OR: 5.99: 95% confidence interval [CI]: 1.64-21.13; and OR: 10.32; 95%CI: 2.75-42.49, respectively). Sensitivity and specificity were 71.4 and 79.6%, respectively, for developing PE (area under the curve [AUC]: 0.922). The Kaplan-Meier curve showed that a UtAPI of 0.76 (95%CI: 0.58-1.0) in the 1st trimester was associated with early PE, and a UtAPI of 0.73 (95%CI: 0.55-0.97) in the 3rd trimester was associated with late PE. Conclusion Uterine arteries proved to be a useful predictor tool in the 1st and 3rd trimesters for early PE and in the 3rd trimester for late PE in a pregnant population with high prevalence of PE.

Resumo Objetivo Avaliar o índice médio de pulsatilidade da artéria uterina (UtAPI) em cada trimestre da gravidez como preditor de pré-eclâmpsia (PE) precoce ou tardia em gestantes colombianas. Métodos O UtAPI foi medido em gestações únicas em cada trimestre. O UtAPI como preditor de PE foi avaliado por odds ratio (OR), curvas receiver operating characteristic (ROC) e diagrama de Kaplan-Meier. Resultados A análise no 1° e 3° trimestres mostrou que um UtAPI anormal foi associado com PE inicial (OR: 5,99; intervalo de confiança [IC] 95%: 1,64-21,13; OR: 10,32; IC95%: 2,75-42,49, respectivamente). A sensibilidade e a especificidade foram de 71,4 e 79,6%, respectivamente, para o desenvolvimento de PE (area under the curve [AUC]: 0,922). A curva de Kaplan-Meier mostrou que um UtAPI de 0,76 (IC95%: 0,58- 1,0) no 1° trimestre foi associado com PE precoce, e que um UtAPI de 0,73 (IC95%: 0,55-0,97) no 3° trimestre foi associado com PE tardia. Conclusão As artérias uterinas mostraram ser uma ferramenta preditora útil no 1° e 3° trimestres para PE inicial e no 3° trimestre para PE tardia em uma população de gestantes com alta prevalência de PE.

Doppler de arteria umbilical en fetos con síndrome de Down / Umbilical artery Doppler in fetuses with Down syndrome

INTRODUCCIÓN: La aneuploidía más común entre los recién nacidos vivos es el síndrome de Down (SD). En estos niños el crecimiento está disminuido, con una frecuencia del 25% de restricción del crecimiento intrauterino, pero no se ha establecido el papel de la insuficiencia placentaria. El objetivo es estudiar la resistencia placentaria a través del Doppler de arteria umbilical con índice de pulsatilidad (IP) y el tiempo medio de desaceleración (t/2), y el posible efecto de la insuficiencia placentaria en fetos con SD. MÉTODO: Se realizó Doppler en la arteria umbilical en 78 fetos con SD, se midieron el IP y el t/2, y se compararon los resultados con los pesos de nacimiento. RESULTADOS: Se estudiaron 78 fetos con SD con 214 mediciones Doppler. El t/2 y el IP estaban alterados en el 71,5% y el 65% de las mediciones, respectivamente. La incidencia de t/2 alterado aumenta con la edad gestacional desde un 28,6% a las 15-20 semanas hasta un 89,3% sobre las 36 semanas (p < 0,01); cifras similares se observan para el IP. La clasificación de los pesos fue: 64% adecuados, 12% grandes y 24% pequeños para la edad gestacional. La última medición de t/2 antes del parto era normal en el 17% y estaba alterada en el 83%. En el caso del IP, los valores fueron normales en el 27% y anormales en el 73%. El peso de nacimiento, la edad gestacional y el porcentaje de niños adecuados para la edad gestacional eran significativamente mayores en el grupo con Doppler normal que en el grupo con Doppler alterado. El z-score del t/2 estaba marcadamente alterado (−2.23), pero el del peso de nacimiento solo estaba algo disminuido (−0,39). La mortalidad perinatal fue del 10%, significativamente mayor cuando el flujo diastólico era ausente o reverso. CONCLUSIONES: El estudio demuestra que los fetos con SD tienen una alta incidencia de alteración del Doppler umbilical para el IP y el t/2, lo cual sugiere una insuficiencia placentaria grave. Este deterioro parece iniciarse hacia el final del segundo trimestre y aumenta con la edad gestacional. Sin embargo, en estos fetos, la insuficiencia placentaria produce una ligera caída en el crecimiento fetal. Como hipótesis general pensamos que en los fetos con SD hay datos claros de insuficiencia placentaria, pero habría algún factor que les protegería de una restricción grave del crecimiento.

INTRODUCTION: The most common aneuploidy in live newborns is Down syndrome (DS), in these children growth is decreased, with a frequency of 25-36% of fetal growth restriction (FGR); however, it is not established the role of placental insufficiency. The objective is to study the Doppler of the umbilical artery with pulsatility index (PI) and half peak systolic velocity (hPSV) deceleration time and the possible role of placental insufficiency in fetuses with DS. METHOD: Doppler was performed in fetuses with DS, the umbilical artery and IP and hPSV were measured, and the results were compared with birth weights. RESULTS: 78 fetuses with DS were studied with 214 Doppler measurements. hPSV and the IP were altered in 71.5% and 65% of the measurements; the incidence of abnormal hPSV increases with gestational age from 28.6% between 15 to 20 weeks, to 89.3% over 36 weeks (p < 0.01), similar figures are observed with respect to the PI. The weight classification was: 24% of FGR, 12% of great for age and 64% of adequate for gestational age (AGA). The last measurement of hPSV before delivery was normal in 17% of the fetuses and was abnormal in 83%, in the case of PI the normal and abnormal values were 27 and 73%, respectively. Birth weight, gestational age, and the percentage of AGA children were significantly higher in the normal Doppler group than in the abnormal Doppler group. The hPSV z-score was markedly altered (−2.23), but the birth weight z-score is slightly decreased (−0.39). Perinatal mortality is 10% and is significantly higher when diastolic flow is absent or reverse. CONCLUSIONS: The study shows that DS fetuses have a high incidence of abnormal umbilical Doppler measured with IP and hPSV, which suggests severe placental insufficiency, this deterioration seems to start towards the end of the second trimester and increases with gestational age. However, in these fetuses, placental insufficiency causes a discrete drop in fetal growth. As a general hypothesis, we think that there is clear evidence of placental insufficiency in fetuses with DS, but there would be some factor that would protect these fetuses from severe growth restriction.

Pulsatile varicose veins: an uncommon presentation of a common condition / Varizes pulsáteis: uma apresentação incomum de uma condição comum

Abstract Varicose veins of the lower limbs are common. However, pulsatile varicose veins are unusual. They could be an indicator of a sinister underlying pathology, such as severe cardiac dysfunction. It is easy to miss these rare cases during clinical workup, which can result in futile treatment with potentially dangerous consequences. In this report, we describe 2 cases of pulsatile varicose veins that highlight different etiologies and management strategies for this condition.

Resumo Varizes dos membros inferiores são comuns. Entretanto, varizes pulsáteis são raras, podendo ser indicadoras de uma patologia subjacente sombria como disfunção cardíaca grave. É fácil deixar passar esses casos raros durante exames clínicos, o que pode resultar em tratamento fútil com consequências potencialmente perigosas. Neste relato, descrevemos dois casos de varizes pulsáteis que evidenciam as diferentes etiologias e estratégias de manejo para essa condição.

Varizes pulsáteis simulando aneurisma de artéria femoral: relato de caso / Pulsatile varicose veins simulating femoral artery aneurysm: case report

Resumo A regurgitação tricúspide severa é citada como fator associado ao desenvolvimento ou à recidiva de varizes em membros inferiores as quais podem, retrogradamente, apresentar um fluxo pulsátil. O diagnóstico etiológico diferencial desse achado ultrassonográfico deve ser feito com a pesquisa de fístulas arteriovenosas, tendo em vista as diferentes formas de tratamento. Dada a complexidade do estado geral dos pacientes com regurgitação tricúspide, a escolha do tratamento das varizes pulsáteis deve ser individualizada, fruto de uma avaliação multidisciplinar. Fazem parte do arsenal terapêutico todas as técnicas habitualmente empregadas no tratamento de varizes, bem como a associações entre elas a serem escolhidas levando-se em conta a gravidade das manifestações clínicas e o risco cardiovascular envolvido. Relatamos um caso de varizes pulsáteis secundárias a regurgitação tricúspide, diagnosticado durante a suspeita primária de aneurisma de artéria femoral em paciente de 73 anos, com a classificação clínica da doença venosa (CEAP) 4a, oligossintomática, tratada com medidas posturais e elastocompressão.

Abstract Severe tricuspid regurgitation is mentioned as a factor associated with development or recurrence of varicose veins in the lower limbs and may present with retrograde pulsatile flow. Differential etiological diagnosis of this ultrasound finding must include investigation of arteriovenous fistulas, since the treatment methods are different. Given the complexity of the general condition of patients with tricuspid regurgitation, treatment for pulsatile varices should be chosen on a case-by-case basis after multidisciplinary evaluation. All of the techniques commonly used to treat varicose veins are part of the therapeutic arsenal, as well as combinations of them, taking into account the severity of clinical manifestations and the cardiovascular risk involved. We report a case of pulsatile varices secondary to tricuspid regurgitation diagnosed when investigating a primary suspicion of femoral artery aneurysm in a 73-year-old patient, CEAP 4a, oligosymptomatic, who was treated with postural measures and elastic compression.

The relationship between serum ischemia-modified albumin levels and uterine artery doppler parameters in patients with primary dysmenorrhea

Abstract Objective Primary dysmenorrhea occurs due to abnormal levels of prostanoids, uterine contractions, and uterine blood flow. However, the reasons for pain in primary dysmenorrhea have not yet been clarified. We examined the blood flow alterations in patients with primary dysmenorrhea and determined the relationship between ischemia-modified albumin (IMA) levels, as an ischemia indicator, and primary dysmenorrhea. Methods In the present study, 37 patients who had primary dysmenorrhea and were in their luteal and menstrual phase of their menstrual cycles were included. Thirty individuals who had similar demographic characteristics, who were between 18 and 30 years old and did not have gynecologic disease were included as control individuals. Their uterine artery Doppler indices and serum IMA levels were measured. Results Menstrual phase plasma IMA levels were significantly higher than luteal phase IMA levels, both in the patient and in the control groups (p < 0.001). Although the menstrual phase IMA levels of patients were significantly higher than those of controls, luteal phase IMA levels were not significantly different between the two groups. Menstrual uterine artery pulsatility index (PI) and resistance index (RI) of primary dysmenorrhea patients were significantly different when compared with luteal uterine artery PI and RI levels. There was a positive correlation between menstrual phase IMA and uterine artery PI and RI in the primary dysmenorrhea. Conclusion Ischemia plays an important role in the etiology of the pain, which is frequently observed in patients with primary dysmenorrhea. Ischemia-modified albumin levels are considered as an efficient marker to determine the severity of pain and to indicate ischemia in primary dysmenorrhea.

Gestantes con índice de pulsatilidad alterado en ecografía Doppler / Pregnant women with altered pulsatility index in Doppler echography

Introducción: La ecografía Doppler de las arterias uterinas es una técnica propuesta para predecir el riesgo de preeclampsia, retardo del crecimiento intrauterino y otras alteraciones perinatales adversas. Objetivos: Determinar la frecuencia de gestantes con alteración en las arterias uterinas durante el primer trimestre e identificar la presencia de preeclampsia/eclampsia, así como sus principales características clínicas. Métodos: Se efectuó un estudio descriptivo y longitudinal de 168 gestantes en el primer trimestre de embarazo, pertenecientes al municipio de Tercer Frente en Santiago de Cuba, evaluadas en una pesquisa de Genética realizada en el Policlínico Docente Cruce de los Baños, de abril a noviembre de 2018. A todas se les realizó ecografía Doppler para calcular el índice de pulsatilidad de las arterias uterinas. Resultados: En la casuística, 16 pacientes presentaron alterado el índice de pulsatilidad y, de ellas, solo en 3 se desarrolló preeclampsia, para 18,7 %; la edad promedio en estas últimas fue de 29 años y 2 eran nulíparas (66,6 %). Respecto al índice de pulsatilidad, el promedio fue de 2,5. Conclusiones: Se mantuvo un estrecho seguimiento, hasta el parto, de las pacientes con resultados patológicos, y se destacó la importancia de estudiar el índice de pulsatilidad de las arterias uterinas durante el primer trimestre del embarazo, sobre todo en las nulíparas.

Introduction: The Doppler echography of the uterine arteries is a technique suggested to predict the risk of pre-eclampsia, the intrauterine growth retardation and other adverse perinatal disorders. Objectives: To determine the frequency of pregnant women with disorder in the uterine arteries during the first trimester and to identify the pre-eclampsia/eclampsia presence, as well as their main clinical characteristics. Methods: A descriptive and longitudinal study of 168 pregnant women in the first trimester of pregnancy, belonging to the Tercer Frente municipality in Santiago de Cuba was carried out, they were evaluated by investigation of Genetics in Cruce de los Baños Teaching Polyclinic from April to November, 2018. To determine the pulsatility index of the uterine arteries, a Doppler echography was carried out. Results: In the case material 16 patients presented this parameter altered and just 3 pregnant women presented pre-eclampsia, for 18.7 %; the average age of these last ones was of 29 years and 2 were nonparous (66.6 %). Regarding the pulsatility index, the average was of 2.5. Conclusions: There was a close follow up of the patients with pathological results, until the childbirth, and the importance of studying the pulsatility index of the uterine arteries in the first trimester of the pregnancy, mainly in the nonparous, was emphasized.

Predictive value of transcranial doppler ultrasound for cerebral small vessel disease in elderly patients / Valor preditivo do ultrassom doppler transcraniano para doença de pequenos vasos em pacientes idosos

ABSTRACT Objective: To investigate the predictive value of transcranial Doppler (TCD) ultrasound for cerebral small vessel disease in elderly patients. Methods: Transcranial Doppler ultrasound and magnetic resonance imaging (MRI) were performed on 184 elderly patients with cerebral small vessel disease. The relationship of clinical characteristics and TCD ultrasound parameters with severe white matter lesions (WMLs) in MRI were investigated by univariate analysis and multivariate analysis. Results: The univariate analysis showed that age, left middle cerebral artery (MCA) mean flow velocity, right MCA mean flow velocity and mean MCA pulsatility index were significantly correlated with severe WMLs (p < 0.05). The multivariate logistic regression analysis showed that only age (odds ratio: 1.21; 95%CI: 1.10-1.36; p < 0.01) and MCA pulsatility index (dominance ratio: 1.13; 95%CI: 1.06-1.80; p = 0.02) were significantly correlated with severe WMLs. The analysis of TCD ultrasound parameters showed that when the cut-off for MCA pulsatility index was 1.04, it could identify severe WMLs. The area under the curve was 0.70 (95%CI: 0.60-0.80). The sensitivity and specificity were 63.0% and 72.0%, respectively. The positive and negative predictive values were 35.4% and 86.6%, respectively. Conclusion: The MCA pulsatility index in TCD ultrasound is significantly correlated with severe WMLs; and TCD ultrasound can guide selective MRI for the detection of WMLs.

RESUMO Objetivo: Investigar o valor preditivo do ultrassom de Doppler transcraniano (TCD) para doença de pequenos vasos (SVD) em pacientes idosos. Métodos: ultrassonografia de TCD e ressonância magnética (RM) foram realizadas em 184 idosos portadores de SVD cerebral. As relações das características clínicas e os parâmetros ultrassonográficos do TCD com lesão grave de substância branca (WML) no desempenho da RM foram investigados por análise univariada e análise multivariada. Resultados: A análise univariada mostrou que, a idade, a velocidade média de fluxo (MFV) da artéria média cerebral (MCA) esquerda, a MFV da MCA direita e o índice de pulsatilidade (PI) médio estiveram significativamente relacionados à WML grave (P <0,05). A análise de regressão logística multivariada mostrou que apenas a idade (razão de chances: 1,21; IC95%: 1,10-1,36; P <0,01) e o PI da MCA (razão de dominância: 1,13; IC 95%: 1,06-1,80; P = 0,02) estiveram significativamente relacionados a WML grave. A análise dos parâmetros ultrassonográficos do TCD mostrou que, quando o ponto de corte do IP do MCA foi 1,04, ele pôde identificar à WML grave. A área sob a curva foi de 0,70 (IC 95%: 0,60-0,80). A sensibilidade e especificidade foram de 63,0% e 72,0%, respectivamente. Os valores preditivos positivos e negativos foram de 35,4% e 86,6%, respectivamente. Conclusão: O PI da MCA na ultrassonografia do TCD está significativamente relacionado à WML grave. A ultrassonografia TCD pode orientar a ressonância magnética seletiva para detecção da WML.

Máquina de perfusão versus armazenamento estático na preservação renal de doadores com morte encefálica: revisão sistemática e metanálise / Machine perfusion versus cold storage in renal preservation of deceased donors with brain death: systematic review and meta-analysis

RESUMO Com a utilização crescente da máquina de perfusão no transplante renal, tem sido constatado que a isquemia dinâmica correlaciona-se à melhora da preservação orgânica. Nesse contexto, realizamos uma revisão sistemática que procurou avaliar a eficácia do uso de máquina de perfusão portátil (LifePort Kidney Transporter Machine®), utilizada no Brasil, comparada ao armazenamento estático, no que tange à função retardada do transplante renal de doadores com morte encefálica. Foi efetuada pesquisa bibliográfica, nas bases LILACS, MEDLINE via PubMed, Scopus, Clarivate Analytics, Cochrane Library, Embase, SciELO, além de busca manual no Google acadêmico. A revisão sistemática, finalizada em abril 2017, foi constituída somente por ensaios clínicos randomizados. Para metanálise, foram avaliadas Razão de Risco e Razão de Chance. Foram identificados 86 documentos e selecionados, ao final, dois artigos com critérios de elegibilidade para metanálise, de grupos europeus e brasileiros. Nestes, 374 rins foram alocados para a máquina de perfusão, e igual número para o armazenamento estático. A função retardada do enxerto foi constatada em 84 e 110 pacientes, respectivamente. Na metanálise, foram obtidas uma Razão de Risco de 0,7568 (p=0,0151) e uma Razão de Chance de 0,6665 (p=0,0225), ambas com intervalo de confiança de 95%. A máquina de perfusão reduziu a incidência de função retardada do enxerto de doadores com morte encefálica.

ABSTRACT With the increasing use of machine perfusion in kidney transplantation, it has been observed that dynamic ischemia correlates with the improvement of organ preservation. In this context, we performed a systematic review that aimed to evaluate the efficacy of the portable machine perfusion (LifePort Kidney Transporter Machine®), used in Brazil, compared to cold storage, regarding the delayed graft function of deceased donors with brain death. Literature search was carried out in LILACS, MEDLINE via PubMed, Scopus, Clarivate Analytics, Cochrane Library, Embase, and SciELO, as well as in Google Scholar manually. The systematic review consisted only of randomized clinical trials. For meta-analysis, relative risk and odds ratio were evaluated. Eighty-six documents were identified and two papers from European and Brazilian groups were selected at the end, with eligibility criteria for meta-analysis. In these, 374 kidneys were assigned to machine perfusion and 374 kidneys were assigned to cold storage. Delayed graft function was observed in 84 and 110 patients, respectively. In meta-analysis, a risk ratio of 0.7568 (p=0.0151) and an odds ratio of 0.6665 (p=0.0225) were obtained, both with a 95% confidence interval. Machine perfusion reduced the incidence of delayed graft function of deceased donors with brain death.

Evaluation of choroidal perfusion changes in obese patients: ocular effects of insulin resistance / Avaliação das alterações da perfusão coroidiana em pacientes obesos: efeitos oculares da resistência à insulina

ABSTRACT Purpose: We aimed to evaluate choroidal per­fusion changes in obese patients using optical coherence tomography and dynamic contour tonometry, to determine whether these changes are associated with body mass index, and to assess the ocular effects of insulin resistance. Methods: We retrospectively evaluated the data of 32 obese patients with body mass index >30 kg/m2 and 45 healthy control individuals. Intraocular pressure and ocular pulse amplitude values of the patients were measured using dynamic contour tonometry, and the mean choroidal thickness was measured using enhanced depth imaging optical coherence tomography. Insulin resistance was assessed using the homeostasis model assessment-estimated insulin resistance index. Results: The mean choroidal thickness (294.30 ± 60.87 μm) and ocular pulse amplitude (2.10 ± 0.74) were lower, whereas the mean intraocular pressure (16.61 ± 2.35 mmHg) was higher in obese patients than in controls. There was a significant negative correlation between body mass index and ocular pulse amplitude (r=-0.274; p=0.029) and an insignificant negative correlation between mean choroidal thickness, intraocular pressure, and body mass index. There was an insignificant negative correlation between homeostasis model assessment-estimated insulin resistance index, mean choroidal thickness, and intraocular pressure and significant ne­gative correlation between homeostasis model assessment-estimated insulin resistance index and ocular pulse amplitude (r=-0.317; p=0.022). Conclusion: We found reduced mean choroidal thickness and ocular pulse amplitude and increased mean intraocular pressure in obese patients. These changes indicated a decrease in choroidal perfusion and ocular blood flow. It may be possible to detect ocular blood flow changes in obese patients through noninvasive assessment using the choroid. The negative correlation between insulin resistance and ocular pulse amplitude may be associated with intracellular fat accumulation in obese patients.

RESUMO Objetivo: Avaliar as alterações da perfusão coroidiana em pacientes obesos utilizando tomografia de coerência óptica e a tonometria de contorno dinâmico, para determinar se essas alterações estão associadas ao índice de massa corporal e avaliar os efeitos oculares da resistência à insulina. Métodos: Foram avaliados, retrospectivamente, os dados de 32 pacientes obesos, com índice de massa corporal >30 kg/m2, e 45 controles saudáveis. Os valores de pressão intraocular e da amplitude de pulso ocular dos pacientes foram medidos por meio de tonometria de contorno dinâmico e a espessura média da coroide foi medida por tomografia de coerência óptica com profundidade de imagem aprimorada. A resistência à insulina foi avaliada usando o índice de estimativa da resistência à insulina pelo modelo de homeostase. Resultados: A espessura média da coroideia (294,30 ± 60,87 μm) e a amplitude de pulso ocular (2,10 ± 0,74) foram menores, enquanto a pressão intraocular média (16,61 ± 2,35 mmHg) foi maior nos obesos do que nos controles. Houve uma correlação negativa significativa entre o índice de massa corporal e a amplitude de pulso ocular (r=-0,274; p=0,029) e uma correlação negativa insignificante entre a espessura média da coroide, a pressão intraocular e o índice de massa corporal. Houve uma correlação negativa insignificante entre a avaliação do modelo de homeostase - estimativa do índice de resistência à insulina, espessura média da coróide e pressão intraocular e correlação negativa significativa entre o modelo de avaliação de homeostase - o índice de resistência à insulina estimado e a amplitude de pulso ocular (r=-0,317; p=0,022). Conclusão: Encontramos redução da espessura média da coroide e da amplitude de pulso ocular e aumento da pressão intraocular em pacientes obesos. Essas alterações indicaram uma diminuição na perfusão coroidal e no fluxo sanguíneo ocular. Pode ser possível detectar alterações no fluxo sanguíneo ocular em pacientes obesos por meio de avaliação não invasiva usando a coróide. A correlação negativa entre a resistência à insulina e a amplitude de pulso ocular pode estar associada ao acúmulo de gordura intracelular em pacientes obesos.

Vascular Aging and Arterial Stiffness / Envelhecimento Vascular e Rigidez Arterial

Abstract Cardiovascular diseases (CVD) account annually for almost one third of all deaths worldwide. Among the CVD, systemic arterial hypertension (SAH) is related to more than half of those outcomes. Type 2 diabetes mellitus is an independent risk factor for SAH because it causes functional and structural damage to the arterial wall, leading to stiffness. Several studies have related oxidative stress, production of free radicals, and neuroendocrine and genetic changes to the physiopathogenesis of vascular aging. Indirect ways to analyze that aging process have been widely studied, pulse wave velocity (PWV) being considered gold standard to assess arterial stiffness, because there is large epidemiological evidence of its predictive value for cardiovascular events, and it requires little technical knowledge to be performed. A pulse wave is generated during each cardiac contraction and travels along the arterial bed until finding peripheral resistance or any bifurcation point, determining the appearance of a reflected wave. In young individuals, arteries tend to be more elastic, therefore, the reflected wave occurs later in the cardiac cycle, reaching the heart during diastole. In older individuals, however, the reflected wave occurs earlier, reaching the heart during systole. Because PWV is an important biomarker of vascular damage, highly valuable in determining the patient's global cardiovascular risk, we chose to review the articles on vascular aging in the context of cardiovascular risk factors and the tools available to the early identification of that damage.

Resumo As doenças cardiovasculares são anualmente responsáveis por quase um terço do total de mortes no mundo. Dentre elas, a hipertensão arterial sistêmica (HAS) está relacionada com mais da metade desses desfechos. O diabetes mellitus tipo 2 é visto com um fator de risco independente para HAS por causar lesões funcionais e estruturais na parede arterial, ocasionando-lhe enrijecimento. Diversos estudos relacionam o stress oxidativo, a produção de radicais livres, as alterações neuroendócrinas e genéticas com a fisiopatogenia do envelhecimento vascular. Formas indiretas para analisar esse processo de envelhecimento têm sido amplamente estudadas, dentre elas, a velocidade de onda de pulso (VOP) é vista como o padrão-ouro para avaliar a rigidez arterial por existir maior número de evidências epidemiológicas do seu valor preditivo para eventos cardiovasculares além de requerer pouco conhecimento técnico para sua realização. A onda de pulso é gerada durante cada contração cardíaca e percorre o leito arterial até encontrar resistência periférica ou algum ponto de bifurcação, ocasionando o surgimento de uma onda refletida. Em indivíduos jovens, as artérias tendem a ser mais elásticas, em consequência, a onda é refletida mais tardiamente no ciclo cardíaco e atinge o coração no momento da diástole, enquanto nos mais velhos, com reflexão mais precoce da onda, tende a acontecer na sístole. Por ser a VOP um importante biomarcador de dano vascular, de grande valia para a determinação do risco global cardiovascular do paciente, optamos por revisar os artigos referentes ao envelhecimento vascular no contexto dos fatores de risco cardiovasculares e as ferramentas disponíveis para a identificação precoce desse dano.

PID controller design to generate pulsatile flow rate for in vitro experimental studies of physiological flows

Producing accurate pulsatile flow rates is essential for many in vitro experimental studies in biofluid dynamics research. A controller system was developed to control a flow loop to produce easily adjustable pulsatile flow rates with sufficient accuracy. An Arduino board is used as a micro-controller to control a pump to produce various pulsatile flow rates, and an open-source proportional-integral-derivative (PID) control algorithm is developed for this purpose. Four non-trivial pulsatile waveforms were produced by the PID controller, as well as an iterative controller, and the performance of both controllers was evaluated. Both the PID and iterative controllers were able to successfully produce slowly-varying signals (single and multi-harmonic low frequency sine waves), but for high frequency signals where the flow has strong acceleration/deceleration (e.g. for physiological waveforms) the iterative controller exhibited significant undershoot. The comparison of PID and iterative controllers suggests that if the desired flow rate is a low frequency, simple waveform then the iterative controller is preferred due to simplicity of implementation. However, if the desired signal is rapidly changing and more complicated then the PID controller achieves better results. This system can be implemented in many flow loops due to its simplicity and low cost, and does not require a mathematical model of the system.

Oral Administration of Cilostazol Increases Ocular Blood Flow in Patients with Diabetic Retinopathy

PURPOSE: To investigate the effect of cilostazol on ocular hemodynamics and to determine whether the administration of cilostazol increases the ocular blood flow in patients with diabetic retinopathy. METHODS: This prospective observational study investigated the effect of orally administered cilostazol on diabetic retinopathy. Before and after administration for 1 week, pulsatile ocular blood flow (POBF) and retrobulbar hemodynamics were measured using a POBF analyzer and transcranial Doppler imaging, respectively. Visual acuity, intraocular pressure, and blood pressure were also evaluated before and after treatment. RESULTS: Twenty-five eyes of 25 patients were included in this study. POBF increased significantly (16.8 ± 4.6 µL/sec vs. 19.6 ± 6.2 µL/sec, p < 0.001) after administration of cilostazol, while no significant change was identified in visual acuity, intraocular pressure, and blood pressure. Mean flow velocity in the ophthalmic artery as measured with transcranial Doppler imaging also increased significantly after medication (23.5 ± 5.6 cm/sec vs. 26.0 ± 6.9 cm/sec, p = 0.001). The change in POBF directly correlated with the change in mean flow velocity (r = 0.419, p = 0.007). CONCLUSIONS: Cilostazol was effective in increasing ocular blood flow in patients with diabetic retinopathy, possibly by modulating retrobulbar circulation.

Duration of systole and diastole for hydrodynamic testing of prosthetic heart valves: comparison between iso 5840 standards and in vivo studies

Abstract Objective: To complement the ISO 5840 standards concerning the duration of left ventricular systole and diastole as a function of changes in heart rates according to in vivo studies from the physiologic literature review. Methods: The systolic and diastolic durations from three in vivo studies were compared with the durations of systole proposed by the ISO 5840:2010 and ISO 5840-2:2015 for hydrodynamic performance assessment of prosthetic heart valves. Results: Based on the in vivo studies analyzed, the systolic durations proposed by the ISO 5840 standard seemed consistent for 45 and 120 beats per minute (bpm), and showed diverse results for the 70 bpm condition. Conclusion: Information on the realistic validation of the operation of left ventricular models for different heart rates were obtained.

Factors influencing the renal arterial Doppler waveform: a simulation study using an electrical circuit model (secondary publication)

PURPOSE: The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI) by using an electrical circuit model to simulate renal blood flow. METHODS: In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff's current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research) and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. RESULTS: Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. CONCLUSION: This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.

The Effect of Pulsatile Versus Nonpulsatile Blood Flow on Viscoelasticity and Red Blood Cell Aggregation in Extracorporeal Circulation

BACKGROUND: Extracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation. METHODS: Mongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was performed before and at 1, 2, and 3 hours after ECC commencement. To eliminate bias induced by hematocrit and plasma, all blood samples were adjusted to a hematocrit of 45% using baseline plasma. Blood viscoelasticity, plasma viscosity, hematocrit, arterial blood gas analysis, central venous O2 saturation, and lactate were measured. RESULTS: The blood viscosity and aggregation index decreased abruptly 1 hour after ECC and then remained low during ECC in both groups, but blood elasticity did not change during ECC. Blood viscosity, blood elasticity, plasma viscosity, and the aggregation index were not significantly different in the groups at any time. Hematocrit decreased abruptly 1 hour after ECC in both groups due to dilution by the priming solution used. CONCLUSION: After ECC, blood viscoelasticity and RBC aggregation were not different in the pulsatile and nonpulsatile groups in the adult dog model. Furthermore, pulsatile flow did not have a more harmful effect on blood viscoelasticity or RBC aggregation than nonpulsatile flow.

The Effect of Pulsatility Index on Infarct Volume in Acute Lacunar Stroke

PURPOSE: Lacunar stroke, in the context of small vessel disease, is a type of cerebral infarction caused by occlusion of a penetrating artery. Pulsatility index (PI) is an easily measurable parameter in Transcranial Doppler ultrasound (TCD) study. PI reflects distal cerebral vascular resistance and has been interpreted as a surrogate marker of small vessel disease. We hypothesized that an increased PI, a marker of small vessel disease, might be associated with a larger infarct volume in acute lacunar stroke. MATERIALS AND METHODS: This study included 64 patients with acute lacunar stroke who underwent TCD and brain MRI. We evaluated the association between the mean PI value of bilateral middle cerebral arteries and infarct volume on diffusion-weighted MRI using univariate and multivariate linear regression. RESULTS: The mean infarct volume and PI were 482.18±406.40 mm3 and 0.86±0.18, respectively. On univariate linear regression, there was a significant positive association between PI and infarct volume (p=0.001). In the multivariate model, a single standard deviation increase of PI (per 0.18) was associated with an increase of 139.05 mm3 in infarct volume (95% confidence interval, 21.25 to 256.85; p=0.022). CONCLUSION: We demonstrated that PI was an independent determinant of infarct volume in acute lacunar stroke. The PI value measured in acute stroke may be a surrogate marker of the extent of ischemic injury.

The prediction of high-sensitivity C reactive protein for peripheral arterial sclerosis in middle-aged population / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the predictive value of high-sensitivity C reactive protein (hsCRP) in middle-aged population during the peripheral arteriosclerosis.</p><p><b>METHODS</b>Random sampling method was used in the study. In 2006-2007 Kailuan Group health examination of 101,510 employees, using stratified random sampling method to select 5,852 as observational cohort included, in the final with a standard queue 5,440 in December 2009. This study selected to participate in the 2012-2013 health examination cohort as the research object, in accordance with the inclusion criteria ultimately selected survey 3,978, select the epidemiological investigation, physical examination, laboratory testing data analysis. Of the 3 978 subjects, 2,282 were male and 1,696 were female, and the baseline age was (53.80±11.14) years. According to the baseline hsCRP quartile level was divided into four groups for comparison of baseline data, using multiple linear regression analysis between hsCRP and brachial-ankle pulse wave velocity (baPWV). Area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the prediction of hsCRP levels in peripheral arteriosclerosis.</p><p><b>RESULTS</b>With increase of hsCRP levels, the survey of baseline levels of baPWV showed increasing trend, (1,445.49±300.55), (1,494.46±307.94), (1,547.67±320.34), (1,621.32±342.53) cm/s, respectively. Multiple linear regression results showed that age, by logarithmic transformation of hsCRP (lghsCRP) level, systolic blood pressure and fasting blood glucose for each additional unit, baPWV levels were increased 266.47, 58.00, 5.02, 39.79 cm/s (P<0.001), and BMI for each additional unit, baPWV level decreased 9.52 cm/s (P=0.030). The prediction of hsCRP in peripheral artery showed that lghsCRP level of AUC to 0.59 (95% CI: 0.57-0.61), lower than the age and systolic blood pressure predicted value AUC (95% CI) of 0.69 (0.67-0.71), 0.75 (0.73-0.77), respectively.</p><p><b>CONCLUSION</b>The hsCRP level could not predict the peripheral arteriosclerosis alone, and the combined age and systolic blood pressure level could have better predictive value.</p>

Incidence and associated risk factors of arterial stiffness in patients with systemic lupus erythematosus / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the prevalence and related risk factors of arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) in patients with systemic lupus erythematosus (SLE).</p><p><b>METHODS</b>The study population included 135 patients currently enrolled in the Chinese SLE Treatment and Research group registry (CSTAR). All traditional cardiovascular risk factors and SLE-related disease factors were collected on the day of the baPWV examination.</p><p><b>RESULTS</b>(1)Significant differences were observed in age (P < 0.000) , family history of cardiovascular disease (P = 0.003), mean blood pressure (P = 0.000) and hemoglobin A1c (P = 0.023) between SLE patients with normal and abnormal arterial stiffness. In addition, SLE patients with abnormal arterial stiffness had lower creatinine clearance rates [85.9 (65.5-108.8) ml/min vs. 106.4 (86.8-124.6) ml/min, P = 0.011], longer disease and hydroxychloroquine duration (P = 0.002 and P = 0.022, respectively), and higher proportion of intravenous cyclophosphamide use (OR = 3.04, 95%CI:1.230-7.514, P = 0.013) as compared to patients with normal arterial stiffness. (2)After adjustment of all confounding factors, age (OR = 4.56, 95%CI: 1.863-11.133, P = 0.001), mean blood pressure (OR = 1.12, 95%CI: 1.055-1.196, P = 0.000) , disease duration (OR = 1.12, 95%CI: 1.050-1.367, P = 0.007) and the proportion of intravenous cyclophosphamide use (OR = 2.86, 95%CI: 1.364-5.979, P = 0.005) remained as independent risk factors for abnormal arterial stiffness in SLE patients.</p><p><b>CONCLUSION</b>Both traditional cardiovascular risk factors and SLE-related factors are associated with the risk of increased arterial stiffness.</p>

Role of computational fluid dynamics in thoracic aortic diseases research: technical superiority and application prospect / 中华外科杂志

Computational fluid dynamics (CFD) technology has the potential to simulate normal or pathologic aortic blood flow changes of mechanical properties and flow field, thereby helping researchers understand and reveal the occurrence, development and prognosis of aortic disease. In aortic diseases research, the initial conditions of CFD numerical simulation has experienced a developed process from idealization (forward engineering), rigid vessel wall, uniform cross-sections, laminar flow and stable blood flow towards personalization (reverse engineering), elastic vessel wall (fluid-solid coupling technique), cone-shaped diminishing cross-sections, turbulent flow, pulsatile blood flow. In this review, the research status, the technical superiority and application prospect of CFD technology were discussed with examples in following three major application areas: (1) dynamics characteristic and mechanical properties in normal thoracic aorta; (2) occurrence, advance and disruptive risk predicting in thoracic aortic aneurysm; (3) therapeutic effect and aneurysmal dilatation simulation in thoracic aortic dissection. For the future, the CFD technology may profoundly put an influence on the awareness to aortic diseases and treatment strategies.