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.

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.

O Índice de Perfusão da Oximetria de Pulso na Avaliação da Função Endotelial na Aterosclerose / Evaluation of Endothelial Function on Atherosclerosis using Perfusion Index from Pulse Oximeter

Fundamento: A disfunção endotelial se caracteriza por um fenômeno vascular, com importância evidente em todos os processos da aterogênese. Interessa, assim, a busca por métodos de avaliação da disfunção endotelial mais acurados, práticos e menos dispendiosos, objetivando melhoria na prevenção e tratamento das doenças ateroscleróticas. Objetivo: Verificar o potencial do índice de perfusão derivado da oximetria de pulso (IPP) como método de avaliação da disfunção endotelial em pacientes portadores de aterosclerose Métodos: Foram selecionados 18 pacientes controles e 24 pacientes portadores de doenças ateroscleróticas, em tratamento otimizado, selecionados em Unidades Básicas de Saúde. Foram avaliados os valores do IPP antes a após a aplicação de um estímulo vasodilatador dependente do endotélio - a hiperemia reativa. Também foram analisados os valores do IPP especificamente no período que possui a maior contribuição do óxido nítrico para a vasodilatação (IPP90-120). Os resultados do IPP foram discutidos, por meio da literatura, estimando o seu potencial diagnóstico e prognóstico. Resultados: A resposta vasodilatadora dependente do endotélio mensurada pelo IPP foi significantemente menor em indivíduos com aterosclerose em comparação aos controles a partir de 45 segundos após a hiperemia reativa. Foram observados, do mesmo modo, valores menores do IPP90-120 em pacientes com aterosclerose [35% (4% - 53%) vs. 73% (55% - 169%); p < 0,001]. Tais valores se mantiveram menores tanto em indivíduos masculinos quanto femininos. Conclusões: Os resultados do IPP, demonstrados na avaliação de pacientes ateroscleróticos, associados ao baixo custo da aparelhagem, tornam esse método ...

Background: Endothelial dysfunction is vascular phenomenon that plays an important role in atherosclerosis development. With the purpose of improving the prevention and treatment of atherosclerotic diseases, the searching for accurate, practical and cheaper methods for evaluating endothelial function have become of interest. Objectives: Verify the potential of Peripheral Perfusion Index from pulse oximetry (IPP) as a method of endothelial dysfunction evaluation in patients with atherosclerotic diseases. Methods: There were recruited 18 control patients and 24 patients with atherosclerotic diseases under optimized treatment, in basic health units. The values of IPP were evaluated before and after an endothelial-dependent stimulus, the reactive hyperemia. The values of IPP were also evaluated in period which the major contribution of Nitric Oxide (NO) for the vasodilation occurs (IPP90-120). The results of IPP were discussed using the literature and estimating their diagnostic and prognostic potential Results: The endothelium-dependent vasodilatory response measured by IPP was significantly lower in patients with atherosclerosis compared to control group, since 45 seconds after reactive hyperemia. Also, the values of IPP90-120 were significantly lower in patients with atherosclerosis [35% (4 - 53%) vs 73% (55 - 169%); p<0,001]. Similarly, the IPP values were lower in atherosclerosis group when it was separated by gender. Conclusion: The results of this study, in association with the low cost of pulse oximeter, suggest a good potential for IPP as an endothelial dysfunction evaluation method. New studies must be done in order to clarify this potential and possibly contribute with the prevention and treatment of atherosclerotic diseases. .

Caracterización del flujo pulsante vascular mediante observaciones in vitro en modelos biológico y mecánico / Characterization of the vascular pulsatile flow through in vitro observations on biologic and mechanical models

Objetivo: Tras las evidencias acumuladas con el uso de dispositivos de asistencia circulatoria de flujo pulsante y continuo, surge la polémica sobre los efectos del tipo de flujo en el sistema circulatorio. Este artículo propone la caracterización del flujo pulsante en conductos elásticos, para analizar la influencia de la pulsación en el sistema y entender las peculiaridades del flujo en el lecho vascular. Métodos: Utilizando un dispositivo de bombeo tipo saco elástico de accionamiento neumático, se procedió a la observación visual e instrumental del flujo a través de conductos tanto flexibles (vaso venoso bovino) como rígidos (tubo plástico), y se analizaron las características biomecánicas de la pulsación en ambos. Resultados: Basado en la observación experimental y el análisis biomecánico del flujo pulsante en un conducto elástico, se caracterizó el patrón de la pulsación y se planteó un modelo que explica la influencia de la pulsación en el sistema vascular y los efectos de su ausencia. El modelo propuesto incluye la condición general de flujo (componente mecánico) y su aplicación al sistema vascular (componente fisiológico). Conclusiones: El modelo planteado permite determinar la relación entre las condiciones del flujo y la reacción de la pared, así como unificar la interpretación de factores fluido-dinámicos involucrados a la vez, que advierte sobre los efectos del cambio de flujo y su significado en lo que sería la operación de dispositivos de asistencia circulatoria.

Objective: The evidence accumulated on the use of pulsatile and non-pulsatile flow-dependent devices raises a controversy concerning the effects of the flow type on the Circulatory system. This paper proposes to characterize the properties of pulsatile flow in elastic conduits in order to determine how the pulse affects the system and to determine the specific details of the flow in the vascular bed. Methods: The biomechanical properties of pulsatile flow were measured on flexible (calf venous vessel), and rigid (plastic pipe) conduits in which the flow was implemented using a pneumatic elastic sack-like pumping device. Results: The experimental data and the biomechanical analysis of the pulsing flow was used to determine the flow pattern in order to develop a mechanical model explaining the effects of the pulse on the vascular system. The resulting model includes the flow's general condition (mechanical component) and its effects on the vascular system (biological/physiological component). Conclusions: The model proposed here allows determining the relationship between the flow conditions and the reaction on the wall; it also allows unifying the interpretation of fluid-dynamic factors affecting these phenomena and represents a warning system about the effects of flow changes on the operation of circulatory assistance devices.

Association of hypertriglyceridaemia with pre-eclampsia, preterm birth, gestational diabetes and uterine artery pulsatility index.

Background. We aimed to determine whether high plasma triglyceride levels in the second trimester of pregnancy are associated with adverse pregnancy outcomes including preterm birth, gestational diabetes mellitus, pre-eclampsia and high uterine artery pulsatility index. Methods. This prospective cohort study was done between 2008 and 2010. Plasma levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride were measured after 8 hours of overnight fasting. We compared the outcomes of 45 pregnant women who had high triglyceride levels (>195 mg/dl) with 135 pregnant women with triglyceride levels <195 mg/dl. The main outcome measures were the incidence of preterm birth, gestational diabetes, pre-eclampsia and uterine artery pulsatility index. Results. Eight women with high triglyceride levels had preeclampsia (17.8% v. 3.7% in the control group, p<0.004), preterm birth occurred in 24.4% and 5.9% in the high triglyceride group and the control group, respectively (OR 5.1, 95% CI 1.9–13.8, p<0.0001). The incidence of gestational diabetes in the high triglyceride group was significantly higher than that in the control group. There was no difference in uterine artery Doppler ultrasound between the two groups. Conclusion. There is a positive relation between hypertriglyceridaemia and pre-eclampsia, preterm birth and gestational diabetes.

Velocidade da onda de pulso em adultos jovens acompanhados por 18 anos: impacto de variáveis pressóricas, antropométricas, metabólicas, inflamatórias e de função endotelial. Estudo do Rio de Janeiro / Pulse wave velocity in young adults followed for 18 years: variable impact of blood pressure, anthropometric, metabolic, inflammatory and endothelial function. Study of Rio de Janeiro

Fundamento: Dados sobre a avaliação não invasiva da rigidez vascular e suas relações com variáveis de risco cardiovascular são escassos em jovens. Objetivo: Avaliar a relação entre a velocidade de onda de pulso (VOP) e a pressão arterial (PA), variáveis antropométricas, metabólicas, inflamatórias e de disfunção endotelial em indivíduos adultos jovens. Método: Foram estudados 96 indivíduos (51 homens) do Estudo do Rio de Janeiro, em duas avaliações, A1 e A2, com intervalo de 17,69+-1,58 anos (16 a 21 anos). Em A1 foram avaliados em suas escolas (10-15 anos - média 12,42+-1,47 anos) e em A2 foram novamente avaliados em nível ambulatorial (26-35 anos - média 30,09+-1,92 anos). Em A1 foram obtidos pressão arterial (PA) e índice de massa corporal (IMC). Em A2 foram obtidos a velocidade da onda de pulso (VOP)-método Complior, PA, IMC, circunferência abdominal (CA), glicose, perfil lipídico, leptina, insulina, adiponectina, o índice de resistência à insulina HOMA-IR, proteína C-Reativa ultrassensivel (PCRus) e as moléculas de adesão E-selectina, Vascular Cell Adhesion Molecule-1(VCAM-1) e Intercellular Achesion Molecule-1 (ICAM-1). Foram obtidos, ainda, a variação da PA e do IMC entre as 2 avaliações. Em A2 os indivíduos foram estratificados segundo o tercil da VOP para cada sexo. Resultados: 1) Os grupos foram constituídos da seguinte forma: Tercil 1:homens com VOP < 8,69 m/s e mulheres com VOP < 7,66 m/s; Tercil 2: homens com VOP >- 8,69 m/s e < 9,65m/s e mulheres com VOP >- 7,66 m/s e < 8,31 m/s; Tercil 3:homens com VOP >- 9,65 m/s e mulheres com VOP >- 8,31 m/s. 2) O grupo com maior tercil de VOP mostrou maiores médias de PA sistólica (PAS) (p=0,005), PA diastólica (PAD) (p=0,007), PA média (PAM) (p=0,004), variação da PAD (p=0,032), variação da PAM (p=0,003), IMC (p=0,046), variação do IMC (p=0,020), insulina (p=0,019), HOMAR-IR (p=0,021), E-selectina (p=0,032) e menores médias de adiponectina (p=0,016), além de maiores prevalências de diabetes ...

Background: Data on non-invasive evaluation of vascular stiffness in the young and its relationship with cardiovascular (CV) risk variables are scarce. Objective: To assess the relationship between pulse wave velocity (PWV) and blood pressure (BP), anthropometric, metabolic, inflammatory and endothelial dysfunction variables in young adults. Methods: Ninety-six individuals (51 males) from The Rio de Janeiro Study cohort were studied in two evaluations, A1 and A2, with and interval of 17.69 +- 1.58 years (16-21 years). In A1 they were evaluated at their schools (10-15 years - aerage 12.42 +- 1.47 years) and in A2 they were all re-evaluated as outpatients (26-35 years - average 30.09 +- 1.92 years). In A1 BP and body mass index (BMI) were obtained. In A2 pulse wave velocity (PWV) by Complior method, BP, BMI, waist circunference (WC), glucose, lipid profile, leptin, insulin, adiponectin, the HOMA-IR insulin resistance index, high sensitive C-Reactive protein (CRPhs) and E-selectin, Vascular Cell Adhesion Molecule 1 (VCAM-1) and Intercellular Adhesion Molecule 1 (ICAM-1) adhesion molecules were obtained. The BP and BMI variation over the time interval between the two evaluations were also obtained. Subjects were stratified according to tertile of PWV for each sex in A2. Results: 1) The groups were constituted as follows: Tertile 1: males with PWV <8.69 m/s and females with PWV <7.66 m/s; Tertile 2: males with PWV >- 8.69 m/s and <9.65 m/s and females with PWV >- 7.66 m/s and <8.31 m/s; Tertile 3: males with PWV >- 9.65 m/s and females with PWV >- 8.31 m/s 2) The group with the highest PWV tertile showed higher values of systolic BP (SBP) (p=0.005), diastolic BP (DBP) (p=0.007), mean BP (MBP) (p=0.004), DBP variation (p=0.032), MBP variation (p=0.033), BMI (p=0.046), BMI variation (p=0.020), insulin (p=0.019), HOMA-IR (p=0.021), E-Selectin (p=0.032) and lower values of adiponectin (p=0.016), besides higher prevalence of diabetes mellitus/glucose intolerance ...

Orbital Doppler Evaluation of Blood Flow Velocities in Optic Neuritis

PURPOSE: To evaluate orbital blood flow velocities and optic nerve diameter with Doppler and gray-scale sonography in patients with acute unilateral optic neuritis (ON). METHODS: Orbital Doppler and gray-scale sonography was performed in 46 eyes of 23 patients aged 19- to 47-years with acute unilateral ON. ON was diagnosed by an ophthalmologist on the basis of clinical presentation, presence of decreased visual acuity and assessment of visual evoked potentials. The peak systolic velocity (PSV) and end-diastolic velocity (EDV), as well as the resistance index (RI) and pulsatile index (PI) of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary arteries (PCAs) and optic nerve diameter were measured in both eyes. We compared results from affected and unaffected eyes using the paired t-test. The area under the receiver operating characteristic (ROC) curves was used to assess the diagnosis of ON based on measured blood flow parameters of the OA, CRA and PCAs and optic nerve diameter. RESULTS: The mean (standard deviation) optic nerve diameter in eyes with ON was 4.1 (0.8) mm, which was significantly larger than the 3.0 (0.4) mm diameter measured in unaffected control eyes (p 0.05). The mean RI in the PCAs was slightly lower in the eyes with ON than in the contralateral eyes (0.60 vs. 0.64, p < 0.05). The area under the ROC curves indicated that optic nerve diameter was the best parameter for the diagnosis of ON. CONCLUSIONS: Optic nerve diameter was related to ON, but orbital blood flow parameters were not.

Evaluation of oral submucous fibrosis using ultrasonographic technique: A new diagnostic tool.

Aim: The aim of this study is to evaluate oral submucous fibrosis (OSMF) by clinical and histopathological examination, and compare the results with those from ultrasonographic technique. Materials and Methods: 30 clinically diagnosed OSMF patients were subjected to both ultrasonographic and histopathological evaluation before treatment. Later, only ultrasonographical examination was done during 4 th and 8 th week of treatment. Prognosis of the lesion for the treatment was evaluated. Peak systolic velocity (PSV) of blood in the lesional area was statistically analyzed. 10 normal individuals without any mucosal lesions were considered as the control group. Results: In normal individuals, ultrasonography delineates normal mucosa with uniform fine mottled appearance with interspersed hypoechoic areas. Color Doppler and spectral Doppler depicts uniform distribution of blood vessels and normal peak systolic velocity of blood respectively. All OSMF patients were diagnosed upon clinical and histopathological examination. Clinical examination revealed 14 individuals with unilateral palpable fibrotic bands and 16 individuals with bilateral fibrotic bands whereas, ultrasonographic evaluation revealed 6 individuals with unilateral fibrotic bands and 24 individuals were with bilateral fibrotic bands, which was statistically significant. Ultrasonography demonstrated number, length and thickness of the fibrotic bands. Color Doppler and spectral Doppler showed decreased vascularity and PSV in lesional area. Prognosis evaluation revealed 25 cases of good prognosis and 5 cases were showed poor prognosis. Wilcoxon Signed Ranks Test revealed no significant difference of PSV was seen in poor prognosis patients. Conclusion: Ultrasonography is a non-invasive diagnostic tool for OSMF. It could be a better diagnostic tool compared to clinical and histopathological examination.

Estimación de la velocidad de propagación aórtica basada en el análisis de la onda de pulso radial / Velocity estimation of aortic propagation based on radial pulse wave analysis

Se exploró la posibilidad de utilizar la morfología del registro de onda de pulso radial obtenida mediante un transductor de movimiento para evaluar la velocidad de propagación aórtica. Se efectuó el registro de onda de pulso en arteria radial mediante un transductor apoyado sobre la zona de palpación del pulso, sobre un conjunto de 167 voluntarios varones sanos normotensos de edades comprendidas entre la 2ª y la 7ª década. Se identificó en los registros la onda reflejada y se definió un coeficiente de velocidad como el cociente entre la talla del individuo y el tiempo transcurrido entre el máximo de la onda sistólica y el instante de llegada de dicha onda. Se halló que en los normotensos el coeficiente mencionado aumentó en forma lineal con la edad, en una proporción similar al aumento de velocidad de propagación aórtica medido con otros métodos. Se repitió el procedimiento en otro conjunto de 125 varones hipertensos sin otros factores de riesgo, de edades entre la 3ª y la 7ª década, hallándose valores similares a los normotensos solamente en la 3ª década, a partir de la cual se registró un incremento significativo de dicho índice. Tales hallazgos sustentan la factibilidad de utilizar tal tipo de registros para evaluar indirectamente la velocidad de propagación junto con el índice de aumentación, un parámetro habitualmente utilizado en el análisis de onda de pulso.

We analyzed the possibility of using the radial pulse wave morphology, obtained by a movement transducer, to evaluate the aortic pulse wave velocity. The radial pulse wave signals were obtained by using a transducer, located on the pulse palpation area, in 167 healthy normotensive male volunteers, ages 20 to 70. The reflected wave was identified in every case. Also, a speed coefficient was defined as the ratio between the individual's height and the time between the maximum systolic wave and the arrival time of the reflected wave. We found that the specified coefficient in normotensive individuals increased linearly with age, in a similar way to the increase in aortic propagation velocity measured by other methods. The procedure was repeated on another set of 125 individuals with hypertension, without other risk factors, aged between the 3rd and 7th decade. This time we found similar values to normotensive individuals only on the 3th decade, and a pronounced increase on the velocity coefficient at advanced ages was observed. These findings support the feasibility of using this type of signals to indirectly evaluate the propagation velocity together with the increase index, a parameter commonly used in pulse wave analysis.

Immediate effects of submaximal effort on pulse wave velocity in patients with Marfan syndrome

Marfan syndrome (MS) is a dominant autosomal disease caused by mutations in chromosome 15, the locus controlling fibrillin 1 synthesis, and may exhibit skeletal, ocular, cardiovascular, and other manifestations. Pulse wave velocity (PWV) is used to measure arterial elasticity and stiffness and is related to the elastic properties of the vascular wall. Since the practice of exercise is limited in MS patients, it was of interest to analyze the acute effect of submaximal exercise on aortic distensibility using PWV and other hemodynamic variables in patients with MS with either mild or no aortic dilatation. PWV and physiological variables were evaluated before and after submaximal exercise in 33 patients with MS and 18 controls. PWV was 8.51 ± 0.58 at rest and 9.10 ± 0.63 m/s at the end of exercise (P = 0.002) in the group with MS and 8.07 ± 0.35 and 8.98 ± 0.56 m/s in the control group, respectively (P = 0.004). Comparative group analysis regarding PWV at rest and at the end of exercise revealed no statistically significant differences. The same was true for the group that used â-blockers and the one that did not. The final heart rate was 10 percent higher in the control group than in the MS group (P = 0.01). Final systolic arterial pressure was higher in the control group (P = 0.02). PWV in MS patients with mild or no aortic dilatation did not differ from the control group after submaximal effort.

Ultrasonografía doppler en embarazos de término con oligohidroamnios aislado / Fetal doppler flow in term pregnancy with isolated oligohydramnios

Objetivos: Evaluar la unidad feto placentaria, mediante ecografía Doppler fetal, en pacientes embarazadas de término con oligohidroamnios aislado (OHA) y comparar los resultados en embarazadas con líquido amniótico normal. Método: Estudio transversal de 19 pacientes con embarazo de término y OHA sin patología asociada. Se compara la evaluación del Doppler con un grupo control de embarazadas con líquido amniótico normal. Como objetivo principal se mide el índice de pulsatilidad (IP) de las arterias renal, cerebral media y umbilical fetal, y como secundarios se evalúan los resultados neonatales. Resultados: Los resultados de la medición Doppler de IP en pacientes con OHA v/s control fueron no significativos: 2,03 v/s 2,04 en arteria renal (p >0,05), 1,37 v/s 1,35 en arteria cerebral media (p >0,05), 0,79 v/s 0,82 en arteria umbilical (p >0,05). Los objetivos secundarios no mostraron diferencias estadísticamente significativas. Conclusión: El OHA aislado en pacientes con embarazo de término no se asocia con alteración del Doppler fetal, por lo que no se relaciona con deterioro de la función placentaria.

Objectives: To evaluate the fetoplacentarian unit through the fetal Doppler flow in term pregnants with oligohidramnios and to compare the fetal outcomes with term pregnants with normal amniotic fuid. Methods: We designed a transversal correlational study of 19 term patients with oligohidramnios and no other pathology. We compare the fetal Doppler values with a control pregnant group with normal amniotic fluid. Our main outcomes were renal, middle cerebral and umbilical artery PI (pulsatility index) and our secondary outcomes were the neonatal results. Results: Patients with oligohidramnios PI Doppler flow values v/s control group were non significant: renal artery 2.03 v/s 2.04 (p >0.05), middle cerebral artery 1.37 v/s 1.35 (p >0.05), umbilical artery 0.79 v/s 0.82 (p>0.05). The secondary outcomes neither were statistically different. Conclusion: There is no association between the isolated oligohidramnios in a term pregnancy and fetal Doppler disorder, for what is not associated with placental dysfunction.

Significado clínico del doppler patológico en la arteria cerebral media en fetos del tercer trimestre / Clinical significance of antenatal pathological doppler findings in the middle cerebral artery in fetuses at third trimester

Antecedentes: La flujometría Doppler fetal es usada de forma rutinaria y sistemática. Es incierta la utilidad clínica del Doppler de la arteria cerebral media (ACM) en fetos del tercer trimestre con crecimiento normal. Objetivo: Determinar los resultados perinatales en fetos del tercer trimestre con índice de pulsatilidad (IP) de la arteria cerebral media (ACM) bajo el percentil 5 comparado con fetos con Doppler cerebral normal. Método: Estudio de cohorte retrospectivo en fetos del tercer trimestre durante 2008. Se seleccionaron dos grupos según IP en la ACM: menor del percentil 5 y mayor del percentil 5. Resultados: Durante el período de estudio 265 fetos cumplieron los criterios de inclusión. Ambos grupos fueron comparables en cuanto a sus características principales. En el grupo con IP menor del percentil 5, la edad gestacional al nacimiento fue mayor: 39,4 vs 38,9 semanas (p=0,001); sin embargo, el número de partos pretérminos fue similar (p=0,89). En el grupo con IP en la ACM menor del 5 se efectuaron 19 (25,7 por ciento) cesáreas por distrés fetal similar al grupo con Doppler cerebral normal 42 (22 por ciento) (p=0,51). No hubo diferencia significativa en ambos grupos respecto al puntaje de Apgar menor de 7 a los 5 minutos (5,4 por ciento vs 3,1 por ciento, p=0,47) ni en el número de ingresos del recién nacido a unidad de cuidados intensivos (10,8 por ciento vs 6,3 por ciento, p=0,32). Conclusiones: Los fetos del tercer trimestre con IP bajo el percentil 5 en el Dopplerde la ACM, muestran resultados perinatales similares a los fetos con Doppler cerebral normal.

Background: Doppler studies are being used routinely and with no specific indication. There is no evidence about the clinical significance of pulsatility index (Pl) below 5th centile in the middle cerebral artery (MCA) in fetuses at third trimester. Objective: To determine perinatal outcomes in fetuses at third trimester with PI<5th centile in the middle cerebral artery (MCA) compared to fetus with normal cerebral Doppler studies. Methods: A retrospective cohort study was designed. We included women pregnant with Doppler studies at third trimester during 2008. We categorized two groups according to the Pl in the MCA, below the 5th centile and above the 5th centile. Results: 265 patients met inclusion criteria. Both groups were similar and homogeneous based on their main characteristics. The Pl below 5th centile group showed a higher mean gestational age 39.4 vs. 38.9 weeks (p=0.001). However, after categorization in preterm delivery below 37 weeks there was no significant difference (p=0.89). In fetuses with PI<5th centile, 19 (25.7 percent) cesarean sections were performed due to fetal distress and similarly 42 (22 percent) cesarean sections were performed in the control group (p=0.51). PI<5th centile was not associated with a 5-min Apgar score below 7 (5.4 percent vs. 3.1 percent, p=0.47). Similarly, there was no difference in the admission to neonatal intensive care unit (10.8 percent vs. 6.3 percent, p=0.31) between both groups. Conclusions: Fetuses at third trimester with pulsatility index below the 5th centile in the cerebral middle artery Doppler have similar perinatal outcomes compared to fetus with normal cerebral Doppler studies.

Análise do perfil hidrodinâmico em diferentes modelos de bombas de rolete utilizadas em circulação extracorpórea / Analysis of the hydrodynamic profile in different roller pumps models used in cardiopulmonary bypass

OBJETIVO: Dentre os equipamentos utilizados em circulação extracorpórea, as bombas de rolete têm grande importância, com diversos modelos disponíveis de vários fabricantes. A calibração é um fator importante nas taxas de hemólise e o seu potencial difere em cada uma delas. Pesquisadores nem sempre abordam detalhes sobre os perfis do leito rígido, supondo que as formas padronizadas de calibração garantem valores iguais e comparáveis para todos os modelos de bombas de rolete. Dispomos principalmente de dois métodos para a calibração das bombas, o que também interfere com o potencial hemolítico. Nenhum dos métodos considera as características de impulsão do fluído, definido pela forma construtiva do leito rígido. O objetivo é avaliar o perfil hidrodinâmico de três modelos de bombas de roletes disponíveis no mercado brasileiro. MÉTODOS: A oclusão dos roletes foi feita por medidas de velocidade de queda e calibração dinâmica. Foram utilizados dois diferentes diâmetros de tubos de silicone (3/8 x 1/16 e 1/2 x 3/32 polegadas). RESULTADOS: Os perfis apresentaram diferenças em suas variâncias. P<0,01 para medidas de velocidade de queda e P<0,0001 para medidas de calibração dinâmica. Foram encontradas diferenças nas variações de pressão entre as bombas analisadas (P<0,002). CONCLUSÃO: As medidas de oclusão são dependentes da forma do leito rígido e comparações envolvendo bombas de rolete devem ser feitas com cautela. Testes com sangue deveriam ser realizados para verificar a influência das variações de pressão na hemólise.

OBJECTIVE: Among the equipments used in cardiopulmonary bypass the roller pumps have great importance with various models available from several manufacturers. The calibration is an important factor in hemolysis rates and its potential is different in each. Researchers do not always approach details on the pump bed profiles assuming that the standardized calibration settings ensure equal and comparable values for all models of roller pumps. We have mainly two methods for calibration of pumps which also interferes on the hemolytic potential. In both of them, the characteristics of fluid impulsion defined by the pump bed design are not considered. The aim of this study is to compare the hydrodynamic profile of three models of roller pumps available in the Brazilian market. METHODS: The rollers occlusion was performed by measures of drop and dynamic calibration. Two different silicone diameter tubes were used (3/8 x 1/16 and 1/2 x 3/32 inches). RESULTS: The profiles showed differences in their variances, P<0.01 for drop rate measures and P<0.0001 for dynamic calibration. Different changes in pressure were found between the pumps analyzed (P<0.002). CONCLUSION: The measures of occlusion are dependent on the design of the pump bed and comparisons involving roller pumps should be performed with caution. Blood tests should be performed to verify the influence of changes in hemolysis pressure.

Doppler das artérias umbilicais e cerebral média fetal após sulfato de magnésio na pré-eclâmpsia / Doppler of the umbilical and fetal middle cerebral arteries after magnesium sulfate in preeclampsia

OBJETIVO: Comparar a relação da artéria umbilical e artéria cerebral média fetal através dos índices dopplervelocimétricos (índice de resistência, índice de pulsatilidade e relação S/D) antes e após a utilização do sulfato de magnésio nas gestantes com pré-eclâmpsia grave (pura ou superposta). MÉTODOS: Foi desenvolvido um estudo do tipo coorte prospectivo, no qual cada sujeito serviu como seu próprio controle. Foram selecionadas 40 gestantes com pré-eclâmpsia grave, submetidas ao exame dopplervelocimétrico antes e após 20 minutos da administração intravenosa de 6 g do sulfato de magnésio. As variáveis estudadas foram os índices dopplervelocimétricos da relação artéria umbilical e cerebral média fetal. A comparação das médias entre as duas medidas (antes e depois) de cada indivíduo foi realizada através do teste t student pareado. A comparação entre a distribuição de freqüência de diagnóstico fetal (normal, redução isolada na resistência da artéria cerebral média e centralizado) foi realizada através do teste Qui quadrado (c²) de Stuart-Maxwell. RESULTADOS: Não foi observada diferença estatisticamente significativa das médias da relação artéria umbilical/cerebral média nos índices dopplervelocimétricos antes e após o sulfato de magnésio. Verificou-se aumento da freqüência de redução isolada na resistência da artéria cerebral média após o sulfato de magnésio (25,0 por cento x 47,5 por cento; p = 0,01). CONCLUSÃO: A administração intravenosa do sulfato de magnésio nas gestantes com pré-eclâmpsia grave resultou em um aumento significativo na freqüência de fetos com diagnóstico de redução da resistência da artéria cerebral média na dopplervelocimetria.

BACKGROUND: To compare the ratio between the fetal middle cerebral artery and the umbilical artery using Doppler flow velocimetry indices (resistance index, pulsatility index and A/B relation) before and after administration of magnesium sulfate to pregnant women with severe preeclampsia (pure or superimposed). METHODS: A prospective cohort study was conducted with each pregnant woman representing her own control. Forty severe preeclamptic women were included and underwent Doppler sonography before and 20 minutes after administration of 6g of magnesium sulfate. Analysis variables were the Doppler flow velocimetry indices evaluating the ratio of the fetal middle cerebral artery to the umbilical artery. To compare the mean indices before and after magnesium sulfate for the same patient, the "t-paired" Student test was used. The Stuart-Maxwell c² was applied to determine the difference of fetal diagnosis (normal, brain-sparing or reduced middle cerebral artery resistance) before and after magnesium sulfate. RESULTS: No significant difference of the mean ratio between the middle cerebral artery and the umbilical artery, before and after administration of magnesium sulfate was observed. After magnesium sulfate (25.0 percent x 47.5 percent; p= 0.01), there was an increased frequency of isolated lower Doppler flow velocimetry indices in the middle cerebral artery. CONCLUSION: Intravenous administration of magnesium sulfate in patients with severe preeclampsia is associated with increased frequency of fetal Doppler diagnosis of reduced resistance in the middle cerebral artery.

Aneurysm pulsatility after endovascular exclusion: an experimental study using human aortic aneurysms

OBJECTIVE: To measure the pulsatility of human aneurysms before and after complete exclusion with an endograft. METHOD: Five aortic aneurysms obtained during necropsy were submitted to pulsatile perfusion before and after implantation of a bifurcated endograft. The specimens were contained in a closed chamber filled with saline solution. A vertical tube attached to the chamber was used to measure volume dislocation in each systole. Mural thrombus was kept intact, and the space around the device was filled with human blood. After each experiment, the aneurysm was opened to check for the correct positioning and attachment of the device. RESULTS: The level of the saline column oscillated during pulsation in each case, with respective amplitudes of 17, 16, 13, 7, and 25 cm before the endograft insertion. After the insertion, the amplitudes dropped to 13, 12, 9, 3.5, and 23 cm, respectively. The differences were not significant. During the post-experimental examination, all devices were found to be in position and well attached to the neck and iliacs. No endoleak was detected during perfusion or by visual inspection. CONCLUSION: Pulsation of an endograft is transmitted to the aneurysm wall even in the absence of endoleak, and should not be interpreted as procedural failure.

Pulsatile Ocular Blood Flow in Healthy Koreans

PURPOSE: To determine the normal reference range of pulsatile ocular blood flow (POBF) values in healthy Korean subjects and to find out the factors that may affect them. METHODS: A total of 280 eyes of 280 normal subjects were included in this study. Best corrected visual acuity (BCVA), intraocular pressure (IOP), axial length, POBF, systemic blood pressure, and pulse rate were measured. The mean, standard deviation, range, and the 5th and 95th percentiles of POBF were calculated, and the influences of various parameters to POBF were determined by multiple regression analyses. RESULTS: The mean POBF value was 766.0+/-221.6 microliter/min in men and 1021.1+/-249.5 microliter/min in women. The 5th and 95th percentiles for POBF values were 486.0 microliter/min and 1140.0 microliter/min in men and 672.0 microliter/min and 1458.0 microliter/min in women. The POBF values were significantly influenced by gender, mean blood pressure, pulse rate, and axial length. CONCLUSIONS: Even though the POBF values were influenced by gender, BP, and axial length, we could define the normal reference range of POBF in healthy Koreans.

Impact of the Metabolic Syndrome and Its Components on Pulse Wave Velocity

BACKGROUND: Pulse wave velocity (PWV) reflects arterial stiffness and may provide an integrated index of vascular status and cardiovascular disease (CVD) risk. Although the individual components of the metabolic syndrome (MS) are well established cardiovascular risk factors, the impact of the MS and its components on PWV has not been well defined. METHODS: Using an automatic wave form analyzer, heart-femoral (hf) and brachial-ankle (ba) PWVs were measured simultaneously in 364 subjects (age, 44.8+/-9.3 years). None of the subjects had clinical atherosclerotic CVD, diabetes, or systemic disease. The association between PWVs and the features of the MS, individual and clustered, were analyzed. RESULTS: By univariate analysis, the individual components of the MS, except for a low HDL-cholesterol level, were associated with increased hfPWV and baPWV. Hypercholesterolemia was also associated with increase in both PWVs. A low HDL-cholesterol level was associated with an increased baPWV. However, by multivariate analysis, none of the components of the MS, except for an elevated blood pressure (BP), was an independent factor affecting hfPWV and baPWV. After controlling for age and gender, hfPWV and baPWV were increased according to the number of MS components present (p<0.001 for both). After controlling for age, gender and BP, the MS was associated with an increased baPWV (p<0.05). CONCLUSIONS: The clustering of MS components may interact to synergistically affect arterial stiffness, even though the individual MS components, except for an elevated BP, do not affect arterial stiffness independently.

Estudio del flujo del líquido cefalorraquídeo (LCR) con cine resonancia magnética (CINE RM) / Cerebrospinal fluid flow Study (LCR) with Cine Magnetic Resonance Imaging (CINE RM)

En el presente trabajo se analiza la experiencia preliminar en la Clínica Las Condes, referida a 69 pacientes. En su indicación predominó la evaluación del tipo de circulación de LCR en quistes aracnoidales, hidrocefalia y malformación de Chiari I con o sin siringomielia. Fue extremadamente útil en los quistes aracnoidales, siendo no comunicantes diez y comunicantes cuatro. En hidrocefalia, ayudó al diagnóstico gracias al flujo hiperdinámico de los ventrículos laterales, producido en esta patología. En la malformación de Chiari I ilustró en forma elegante el efecto pistón, su correción por la descompresiva occipitocervical y la duroplastía de expansión con aponeurosis de pericráneo. Demostró una gran utilidad en el control de funcionalidad de las tercerventrículocisternostomías.

Efeitos da simpaticotomia endoscópica sobre as artérias carótidas e vertebrais na terapêutica cirúrgica da hiperidrose primária / Effects of endoscopic sympathicotomy in carotid and vertebral arteries in the surgical treatment of primary hiperhidrosis

OBJETIVOS: Analisar, em pacientes submetidos a simpaticotomia videotoracoscópica para tratamento da Hiperidrose Primária (HP), as conseqüências hemodinâmicas da desnervação vascular das artérias carótidas e vertebrais após a trans-secção cirúrgica da cadeia simpática torácica (simpaticotomia), através da mensuração de parâmetros ultra-sonográficos. MÉTODO: Vinte e quatro pacientes portadores de HP submetidos a quarenta e oito simpaticotomias torácicas endoscópicas foram avaliados através da mensuração da velocidade de pico sistólico (VPS), velocidade de pico diastólico (VPD), índice de pulsatibilidade (IP) e índice de resistência (IR) nas artérias carótidas comuns, internas e externas, além da artéria vertebral bilateralmente usando o eco-doppler duplex scan. As avaliações foram realizadas antes da intervenção cirúrgica e trinta dias após o procedimento. O teste de Wilcoxon foi usado na análise das diferenças entre as variáveis antes e depois da simpaticotomia. RESULTADOS: A simpaticotomia no nível de T3 foi a trans-secção mais realizada (95,83 por cento), seja isoladamente (25 por cento) ou associada a T4 (62,50 por cento) ou a T2 (8,33 por cento). Houve aumento significativo no IR e no IP da artéria carótida comum bilateralmente (p<0,05). A VPD da artéria carótida interna diminuiu em ambos os lados (p<0,05). A VPS e a VPD da artéria vertebral direita também aumentaram (p<0,05). Achados assimétricos foram observados, de modo que artérias do lado direito foram as mais freqüentemente afetadas. CONCLUSÕES: Alterações hemodinâmicas foram observadas nas artérias vertebral e carótida após simpaticotomia para tratamento de HP. VPS foi o parâmetro mais freqüentemente alterado, principalmente nas artérias do lado direito, representando alterações assimétricas significantes nas artérias carótida e vertebral. Entretanto, são necessárias pesquisas subseqüentes para verificar se essas alterações são definitivas ou temporárias, uma vez que as inferências clínicas somente terão validação se as alterações forem permanentes.