Diámetro basal de la arteria braquial en la evaluación del paciente con hipertensión esencial / Basal diameter of brachial artery when assessing patients with essential hypertension

Introducción: Las enfermedades cardiovasculares de mayor prevalencia y la hipertensión arterial tienen como sustento la aterosclerosis y la disfunción endotelial. La evaluación no invasiva de aterosclerosis subclínica constituye un complemento para la estratificación del riesgo cardiovascular en la evaluación del paciente hipertenso. Objetivo: Determinar la utilidad del diámetro basal de la arteria braquial en la evaluación del paciente con hipertensión arterial esencial. Método: Se realizó un estudio transversal analítico que incluyó 30 pacientes con hipertensión arterial esencial, a quienes se les realizó ultrasonografía para medir el diámetro basal de la arteria braquial, la vasorreactividad dependiente del endotelio y el grosor íntima media carotídeo, así como se precisó su riesgo cardiovascular, el tiempo de evolución y grado de la hipertensión arterial. Para determinar la asociación entre el diámetro arterial y el resto de las variables se utilizaron pruebas estadísticas como ANOVA de una vía y el coeficiente de correlación de Pearson. Resultados: La disfunción endotelial estuvo presente en 83,3 por ciento de los pacientes estudiados. Tanto el grosor del complejo íntima media carotídeo como la vasorreactividad dependiente del endotelio fueron adecuados marcadores de la enfermedad aterosclerótica. El diámetro basal de la arteria braquial tuvo una correlación inversa con la vasorreactividad dependiente del endotelio, y mostró valores medios esperados en relación a la presencia del tabaquismo, y con los peores grados de la enfermedad hipertensiva y el riesgo cardiovascular. Conclusiones: El diámetro basal de la arteria braquial no mostró la asociación esperada para la evaluación del paciente hipertenso esencial en la población estudiada(AU)

Introduction: The most prevalent cardiovascular diseases and high blood pressure are supported by atherosclerosis and endothelial dysfunction. The non-invasive assessment of subclinical atherosclerosis complements the cardiovascular risk stratification when evaluating hypertensive patients. Objective: To determine the value of the basal diameter of the brachial artery in assessing patients suffering from essential arterial hypertension. Method: An analytical cross-sectional study was carried out in 30 patients with essential arterial hypertension. They underwent ultrasonography to measure the basal diameter of the brachial artery, endothelium-dependent vasoreactivity and carotid mean intima thickness, as well as the cardiovascular risk, time of evolution and degree of arterial hypertension. Statistical tests such as one-way ANOVA and Pearson's correlation coefficient were used to determine the association between arterial diameter and the rest of the variables. Results: Endothelial dysfunction was present in 83.3% of the studied patients. Both the thickness of the carotid media intima complex and endothelium-dependent vasoreactivity were adequate markers for atherosclerotic disease. The basal diameter of the brachial artery had inverse correlation with endothelium-dependent vasoreactivity, and it showed expected mean values in relation to the presence of smoking, and with the worst degrees of hypertensive disease and cardiovascular risk. Conclusions: The basal diameter of the brachial artery did not show the expected association for the evaluation of essential hypertensive patients in the studied population(AU)

Hipertensión arterial pulmonar en pediatría / Pulmonary arterial hypertensión in children

La hipertensión arterial pulmonar (HAP) en pediatría comparte características comunes de la enfermedad en adultos, pero está asociada con varios trastornos y desafíos adicionales que requieren enfoques diferentes. En este artículo se analizan los avances recientes, los desafíos actuales y los distintos enfoques para el cuidado de niños con HAP. Se actualizan la definición, epidemiología, clasificación, diagnóstico y tratamiento. Se plantea el uso del cateterismo cardíaco como diagnóstico y las definiciones hemodinámicas de HAP, incluido el test de vasorreactividad. Se proporcionan actualizaciones sobre los enfoques pediátricos específicos del manejo médico e intervencionista de la HAP (incluyendo la derivación de Potts). Aunque la falta de datos de ensayos clínicos para el uso de la terapia dirigida a la HAP, los datos emergentes están mejorando la identificación de objetivos adecuados para la terapia orientada a objetivos en niños.(AU)

Pulmonary arterial hypertension (PAH) in children shares the typical features of the disease in adults, but is associated with different disorders and additional challenges that require different approaches. This article discusses recent developments, current challenges, and different approaches to PAH care in children. Definition, epidemiology, classification, diagnosis, and treatment are updated. The use of cardiac catheterization as a diagnostic tool and hemodynamic definitions of PAH are proposed, including the vasoreactivity test. Updates are provided on specific pediatric approaches to the medical and interventional management of PAH (including Potts shunt). In spite of the lack of clinical trial data for the use of PAH-targeted therapy, emerging data are improving the identification of appropriate targets for therapy in children (AU)

The vascular endothelium: a review series I. Basic aspects of the vascular endothelium / El endotelio vascular: una serie de repaso I. Aspectos básicos del endotelio vascular

The vascular endothelium is a key regulator of blood flow thus blood pressure. Endothelial cells play a major role in vascular biology by modulating both vasodilation and vasoconstriction through autocrine, paracrine, and hormonal-like mechanisms and molecules such as nitric oxide, prostacyclin, endothelin, and thromboxane. Whenever these fail, endothelial dysfunction presents and may further associated with the development and evolution of a number of cardiovascular pathologies.

El endotelio vascular es un regulador clave del flujo sanguíneo y, por tanto, de la presión arterial. La célula endotelial juega un papel de suma importancia en la biología vascular, ya que media tanto la vasodilatación como la vasocontricción, a través de mecanismos autocrinos, paracrinos y endocrinos que involucran moléculas tales como óxido nítrico, endotelina, prostaciclina y tromboxano. Cuando alguno de dichos mecanismos falla, aparece la disfunción endotelial, misma que puede vincularse -en un futuro- al desarrollo y progresión de numerosas patologías cardiovasculares.

Evaluación de la disfunción endotelial en pacientes ambulatorios mayores de 75 años atendidos en un hospital de la tercera edad

Objetivos. Evaluar mediante métodos no invasivos la presencia de disfunción endotelial en pacientes añosos, mayores de 75 años, sin antecedentes cardiovasculares conocidos y su relación con factores de riesgo coronario (FRC). Material y métodos. Se incluyeron en forma prospectiva pacientes ambulatorios que concurren a consultorios externos de un hospital de la tercera edad desde Julio de 2011 a Enero de 2012. Se estudiaron pacientes con edad = 75 años más, por lo menos, uno de los siguientes FRC: hipertensión arterial (HTA), diabetes mellitus (DBT), dislipidemia (DLP), tabaquismo o ex tabaquismo y obesidad. Se excluyeron los pacientes con antecedentes cardiovasculares de infarto previo, stroke, vasculopatía periférica, insuficiencia cardíaca, fibrilación auricular o aleteo auricular, revascularización previa. Se analizaron datos clínicos, de laboratorio, examen físico. Para evaluar disfunción endotelial se utilizó medición de la vasorreactividad de la arteria humeral, luego de 5 minutos de insuflación del manguito y de la administración de dinitrato de isosorbide. Se tomó como test positivo la dilatación menor al 10% del diámetro basal. Además, se midió el complejo íntima-media en las arterias carótidas primitivas en forma bilateral. El análisis multivariado se realizó mediante regresión logística. Resultados. Se incluyeron un total de 53 pacientes con una edad promedio de 80,4 ± 4,1 años, 29 mujeres (55%). En cuanto a los antecedentes el más frecuente fue la HTA (66%), seguido de la DLP (54%), luego ex tabaquismo (37%) y DBT (17%). El test resultó positivo en 23 pacientes (43,4%) con un porcentaje de dilatación de la arteria braquial de 6,1 ± 3% vs 21,9 ± 8%, p=0,0001. No hubo diferencias entre los pacientes con test positivo y negativo en la edad (81 ± 4,3 años vs 79 ± 3,9 años), el espesor íntima-media en ambas carótidas (0,9 ± 0,2 cm vs 0,8 ± 0,1 cm), los valores de HDL (52 ± 8,2 mg/dL vs 50 ± 10 mg/dL), glucemia (105 ± 19 mg/dL vs 102 ± 13 mg/dL) con una tendencia no significativa a mayor LDL (131 ± 35 mg/dL vs 115 ± 23 mg/dL, p=0,06). Con respecto a los FRC no presentaron diferencias en los antecedentes de HTA (69% vs 63%), DBT (16% vs 17%), DLP (60% vs 50%) y ex tabaquismo (30% vs 43%). En el análisis univariado, el test positivo se asoció al antecedente de obesidad (30% vs 10%, p=0,05) y a un mayor diámetro de la arteria humeral (4,3 ± 0,7 cm vs 3,9 ± 0,7 cm, p=0,04). En el análisis multivariado ninguno de los parámetros se asoció a test positivo de disfunción endotelial. Conclusiones. La tasa de disfunción endotelial demostrada por la reactividad de la arteria humeral fue alta en esta población de mayores de 75 años. La disfunción endotelial se asoció al antecedente de obesidad y al mayor diámetro de la artera humeral. Hubo una tendencia no significativa a mayor LDL en pacientes con disfunción endotelial. En el análisis multivariado ninguno de los parámetros se comportó como independiente de disfunción endotelial.

Endothelial dysfunction evaluation across ambulatory patients over 75 years of age treated at hospital for the elderly Objectives. Evaluate endothelial dysfunction through noninvasive techniques in elderly patients over 75 years of age, with no known history of cardiovascular disease, while controlling for some coronary risk factors. Material and methods. A Prospective study design, recruited seniors that received ambulatory care in the (Por Más Salud Dr. César Milstein) from July 2011 to January 2012. Inclusion criteria required patients to be aged = 75 years and have at least one of the following coronary risk factors (CRF): High blood pressure (hypertension), diabetes, dyslipidemia (DLP), smokers or ex-smokers and obesity. Exclusion criteria applied for those patients with cardiovascular history of previous infarction, stroke, peripheral vascular disease, heart failure, atrial fibrillation or flutter, and previous revascularization. We reviewed clinical charts, laboratory tests, and performed a physical examination. We evaluated endothelial dysfunction by measuring the vasoreactivity of the brachial artery after 5 minutes of tensiometer's insufflation and isosorbide dinitrate administration. Our outcome of interest included those subjects with dilation lower than 10% of the baseline diameter of the femoral artery. Multivariate logistic regression was used to analyze the behavior of all variables in a single model. Results. The final sample included 53 patients ranging from 80.4 ± 4.1 years, 29 women (55%). A history of hypertension was frequently reported (66%), followed by DLP (54%), ex-smokers (37%) and diabetes (17%). The outcome criteria was met by 23 patients (43.4%) with a percentage of brachial artery dilation of 6.1 ± 3% vs 21.9 ± 8%, compared to those without the criteria (p=0.0001). Both cases and controls were statistically similar in terms of age (81 ± 4.3 years vs 79 ± 3.9 years), intima-media thickness in both carotid arteries (0.9 ± 0.2 cm vs 0.8 ± 0,1 cm), HDL values (52 ± 8.2 mg/dL vs 50 ± 10 mg/dL), glucose (105 ± 19 mg/dL vs 102 ± 13 mg/dL) with a borderline-significant trend to higher LDL (131 ± 35 mg/dL vs 115 ± 23 mg/dL, p=0, 06). Regarding the CRF, both cases and controls were not significantly different in the history of hypertension (69% vs 63%), diabetes (16% vs 17%), DLP (60% vs 50%) and ex-smokers (30% vs 43%). Univariate analysis showed a positive, significant association between the outcome and history of obesity (30% vs 10%, p=0.05) and wider diameter of the brachial artery (4.3 ± 0.7 cm vs 3.9 ± 0.7 cm, p=0.04). However, those differences did not hold when the multivariate analysis was run. Conclusions. The endothelial dysfunction rate was associated with reactivity of the brachial artery in those older than 75 years of age. In addition, endothelial dysfunction was associated with a history of obesity and the increased diameter of the humeral cunning. There was a borderline-significant association between LDL increment and patients with endothelial dysfunction. However, multivariate analysis did not find any significant differences, suggesting none of the parameters explained endothelial dysfunction.

Avaliação da disfunção endotelial em pacientes ambulatoriais mais de 75 anos de idade, tratados no hospital para idosos Objetivos. Avaliar através da presença de disfunção endotelial não invasiva em pacientes idosos com mais de 75 anos, sem história conhecida de doença cardiovascular e sua relação com fatores de risco coronariano. Material e métodos. Prospectivamente incluídos pacientes ambulatoriais idosos que frequentam um ambulatório do hospital a partir de julho de 2011 a janeiro de 2012. Nós estudamos pacientes com idade = 75 anos, pelo menos um dos seguintes fatores de risco coronariano (CRF): pressão arterial elevada (hipertensão), diabetes, dislipidemia (DLP), ex-fumantes ou não e obesidade. Foram excluídos os pacientes com história de infarto prévio cardiovascular, acidente vascular cerebral, doença vascular periférica, insuficiência cardíaca, fibrilação atrial ou flutter revascularização anterior. Analisamos clínicos, laboratoriais, exame físico. Para avaliar a disfunção endotelial medição utilizada vasorreatividade da artéria braquial, após 5 minutos de manga insuflação administração e dinitrato de isossorbida. Teste positivo foi considerado como a dilatação inferior a 10% do diâmetro da linha de base. Além disso, foi avaliado o complexo íntima-média das artérias carótidas bilateralmente. A análise multivariada foi realizada por meio de regressão logística. Resultados. Foram incluídos um total de 53 pacientes com idade de 80,4 ± 4,1 anos, 29 mulheres (55%). Como antecedente o mais comum foi hipertensão arterial (66%), seguido pelo DLP (54%), ex-fumadores (37%) e a diabetes (17%). O teste foi positivo em 23 pacientes (43,4%), com uma percentagem de dilatação da artéria braquial de 6,1 ± 3% vs 21,9 ± 8%, p = 0,0001. Não houve diferença entre os pacientes com teste positivo e negativo na idade (81 ± 4,3 anos vs 79 ± 3,9 anos), espessura íntima-média carotídea em ambos (0,9 ± 0,2 cm vs 0,8 ± 0 , 1 cm), os valores de HDL (52 ± 8,2 ...

Influence of age and gender on cold pressor response in Indian population.

Cold pressor test (CPT) is a simple and well documented laboratory test to evaluate the propensity for hypertension and sympathetic autonomic functions. Role of sex hormones was tested in the present study for the cold pressor response (CPR) in young adults of both sexes and in elderly population. The subjects comprised of young male (n=55), female (n=32) medical students of 17-25 years and elderly males (n=39) and females (n=25) of 50-70 years of age. The CPT was carried out in young and elderly males and females with one minute immersion of one hand in ice cold water (0-4°C). Both in young males and females the absolute rise in SBP and DBP in response to Cold pressor test (CPT) was highly significant, with diastolic percent rise exceeding systolic. In comparison to young males, the females showed greater percent rise in SBP and DBP. Similarly, in elderly groups of both sexes, CPR was associated with significant absolute rise in SBP and DBP with diastolic percent rise more than systolic in males only. Both in young versus elderly males and young versus elderly females comparison yielded comparable percent rise in SBP and DBP. The SBP and DBP percent rise was again comparable between elderly males and females. The greater responsiveness to CPT in young females could be attributed to increased pain sensitivity to cold, and/or genetic and hereditary factors overwhelming the hormonal protection offered by estrogen and nitric oxide (NO).

Exploración de la hemodinámica en la hipertensión pulmonar mediante cateterismo cardíaco derecho / Exploration of hemodynamics in pulmonary hipertension by right heart catherization

El diagnóstico final de hipertensión pulmonar se realizamediante cateterismo cardíaco derecho. Existe hipertensiónpulmonar cuando la presión media en la arteria pulmonarsupera los 25 mmHg en situación basal. Una adecuadaexploración hemodinámica permite encuadrar la hipertensiónpulmonar en algunos de los cinco grupos de la clasificaciónclínica actual. Se dan las recomendaciones para los diferentesespecialistas de cuándo efectuar el cateterismo derecho, quéparámetros se deben de registrar y como realizar e interpretaruna prueba aguda de vasorreactividad en la hipertensiónarterial pulmonar.

The final diagnosis of pulmonary hypertension is made byright heart catheterization. Pulmonary hypertension is presentwhen the average pressure in the pulmonary artery exceeds 25mm Hg at baseline. Proper hemodynamic assessment allowsclassification of pulmonary hypertension into one of five clinicalcategories. Recommendations are provided for specialists, whento conduct right heart catheterization, which parameters mustbe recorded and how to perform and interpret a test for acutevasoreactivity in pulmonary arterial hypertensio.

Simultaneously Measured CO2 Reactivity in the Basilar and Middle Cerebral Artery: The Utilization of Power M-mode Doppler and Anterior-posterior Probes Fixating Device

BACKGROUND: Studies using a transcranial Doppler (TCD) to establish cerebral vasoreactivity (CVR) have mostly focused on the anterior circulation. The purpose of this study is not only to evaluate the feasibility of the power motion mode Doppler (PMD) with a probes fixating device, but also to simultaneously measure the CVR between the middle cerebral artery (MCA) and the basilar artery (BA) during hypercapnea simulated by the rebreathing technique. METHODS: Twenty eight healthy volunteers were enrolled. Baseline hemodynamic values (heart rate, blood pressure) were measured while volunteers sat in a comfortable position for 5 minutes. The TCD was performed in two steps. First, velocities and spectra of the MCAs were simultaneously monitored. Then, the velocities and spectra of the MCA and BA were simultaneously monitored by a headset that included an anterior-posterior probes fixating device. The equation for CVR was ([maximum mean velocity baseline mean velocity] x 100/baseline mean velocity). RESULTS: Baseline mean velocities were revealed as follows: (64.0+/-13.7, 65.0+/-11.9 cm/s in right and left MCA; p>0.05; 67.3+/-12.2, -45.3+/-7.6 cm/s in dominant MCA and BA). CVR did not differ between the dominant MCA and the BA (46.1+/-12.1, 46.0+/-15.1%; p>0.05), nor between the right and left MCAs (46.9+/-15.2, 46.4+/-14.8%; p>0.05). There was a positive linear correlation between the CVR of the dominant MCA and that of the BA (r=0.856; p<0.001). CONCLUSIONS: PMD with a probes fixating device for accurate insonation is a useful tool for evaluating the relative CVR between the MCA and BA. Our study suggests that CVR values of the BA are similar to those of the MCA.

Diagnosis and treatment of idiopathic pulmonary arterial hypertension / 대한내과학회지

Idiopathic pulmonary arterial hypertension (previous primary pulmonary hypertension) was a progressive disease with high mortality. Many patients with idiopathic pulmonary arterial hypertension did not show vasoreactivity, rapidly resulted in marked disability, right heart failure and death. Recent advances of therapeutic modalities have revolutionized the treatment of idiopathic pulmonary arterial hypertension. Irrespective of pulmonary arterial vasoreactivity, new vasodilatng agents, such as epoprostenol, treprostinil, iloprost, bosentan, and sildenafil, significantly improved hemodynamics, symptoms, exercise capacities, quality of life, and survival. The median survival of patients with idiopathic pulmonary arterial hypertension has been prolonged from 2.8 years to more than 5 years. In a near future, pulmonary arterial hypertension could be easily controlled like a systemic arterial hypertension.

Cerebral Vasoreactivity by Transcranial Doppler and Brain SPECT in Patients with Unilateral Carotid Stenosis

BACKGROUND: Cerebral vasoreactivity (CVR) is known as having insufficient hemodynamic circulation. However, available information for its clinical interpretation is scant. We attempted to find the relationship of CVR with parameters such as stenosis degree and collateral patterns. METHODS: This study was prospectively conducted in 37 patients with more than 50% angiographically proven unilateral carotid stenosis. The relative change of mean flow velocity before and after an acetazolamide challenge was calculated by transcranial Doppler sonography (TCD) and the results were compared with single photon emission computed tomography (SPECT) results. The degree of stenosis and collateral flow patterns were estimated and classified by conventional angiography. RESULTS: The CVR of middle cerebral artery (MCA) was significantly decreased in the ipsilateral side to the carotid stenosis (p<0.05). The CVR impairment was more severe when symptomatic stenosis was present (p=0.04). There was a significant correlation between the degree of carotid stenosis and the CVR (p<0.01). In the area of impaired CVR by SPECT, the estimated CVR was significantly lower (p<0.05), even to the negative value, implying that there is an actually steal phenomenon in that area. CONCLUSIONS: TCD is a useful tool for the assessment of CVR, which can give diverse clinical information based upon the degree of stenosis.

Cerebral CO2 Vasoreactivity by Transcranial Doppler with Rebreathing Method: Comparison between Ischemic Stroke and Normal Control

BACKGROUND: Cerebral vasoreactivity is an index of the autoregulation of cerebral perfusion, and can be measured by functional imaging such as Xe CT, SPECT, PET in reponse to a hypercapneic stimulus. Recently, a transcranial Doppler (TCD) study helped in the evaluation of cerebral CO2 vasoreactivity by a breath holding method and CO2 inhalation. However, the breath holding method had some constrictions in reliability and the CO2 inhalation method is not as feasible to apply to routine study. In order to measure cerebral CO2 vasoreactivity in a routine TCD study conveniently and reliably, we devised a method of rebreathing into a closed volume of a reservoir bag as a hypercapneic stimulus, and applied it to normal volunteers and patients with ischemic stroke. METHODS: We performed a cerebral CO2 vasoreactivity study by the rebreathing method in 22 normal volunteers and 61 ischemic stroke patients. As a hypercapneic stimulus, we applied a fitted mask connected with a closed reservoir bag for about 90 seconds, and the mean flow velocity (MFV) and pulsatility index (PI) were evaluated at the proximal middle cerebral arteries of 50-55 mm depth, before and after the hypercapneic stimulus. Cerebral vasoreactivities as percent increments of MFV in MCA were compared between the two groups. RESULTS: MFV of both the normal control and patient groups increased continuously during the hypercapneic stimulus, but the rate of the increments of MFV markedly diminished after about 60 seconds of rebreathing. The mean cerebral vasoreactivity of 61 MCA's in the ischemic stroke patient group (47.0 +/- 22.0%) was significantly lower than that of 22 MCA's in the normal control group (60.2 +/- 16.0%). But, the percent decrement of PI showed no significant difference between both groups. CONCLUSIONS: We suppose that the rebreathing method is a relatively reliable and convenient technique as a hypercapneic stimulus in determining cerebral CO2 vasoreactivity by TCD. Cerebral vasoreactivity measured by the rebreathing method is significantly lower in the ischemic stroke patient group than in the normal control group, which may reflect that the atherosclerosis itself could cause reduced distensibility of the small arteriole as well as the structural narrowing of the cerebral arteries.

Restoration of Vasoreactivity in Patients with Symptomatic ICA Occlusion after Extracranial-Intracranial Bypass Surgery / 대한뇌혈관학회지

OBJECTIVE: The purpose of this study is to investigate changes of vasoreactivity after STA-MCA anastomosis in patients who develop hemodynamic cerebral ischemia associated with ICA or MCA occlusion. METHODS: Twenty-five patients with hemodyamic infarction due to symptomatic ICA or MCA occlusion were treated with extracranial-intracranial bypass surgery (EIAB). Of these, we enrolled 17 patients who underwent follow-up SPECT and follow-up angiogram. To test vasomotor reactivity, we measured relative regional cerebral blood flow (rrCBF) with SPECT both at rest and after diamox infusion. rrCBF were calculated using the following equation: (lesional radioactivity/contralateral radioactivity) x100. We performed EIAB in patients with impaired vasomotor reactivity. To evaluate changes in vasomotor reactivity after surgery, follow-up brain SPECT was performed 1-6 months after surgery and compared rrCBF before and after surgery. RESULTS: Base line radioactivity ratios did not change after surgery. These ratios after diamox challenge were 59.8+/-4.2%, however, 1-6 months after surgery, ratios increased to 77.7+/-.6% (p<0.05, Paired T-test). Preoperative degree of angiographic collateral circulation did not influence the restoration of vasoreactivity. All but two patients showed good collateral circulation through the bypass. There were no cerebral accidents in any these patients at 6 months to 2 years follow-up. CONCLUSION: These results demonstrate the restoration of vasomotor reactivity distal to the occluded ICA or MCA after EIAB, and also show that measurement of rrCBF using SPECT are useful indicators of the clinical and hemodynamic improvement.

Cerebral Vasoreactivity in Carotid Stenosis or Occlusion Cases: A Transcranial Doppler Study with Acetazolamide (Diamox) Test

BACKGROUND: The aim of this trial was to evaluate the acetazolamide induced vasoreactivity of the cerebral vasculature in patients with carotid stenosis/occlusion, relative changes of blood flow velocity within the middle cerebral artery were measured by transcranial doppler ultrasonography during acetazolamide challenge. To evaluate the effectiveness of extracranial-intracranial bypass surgery in patients with ICA stenosis/occlusion with decreased vasoreactivity, we studied whether the vasoreactivity could show a significant difference between the territorial infarction and borderzone infarction cases. METHODS: To test vasoreactivity in 21 patients with unilateral carotid stenosis or occlusion, we measured blood flow velocity in the middle cerebral artery by transcranial doppler sonography both at rest and after injection of acetazolamide. Among 21 patients, 13 patients are MCA territorial and 8 patients are borderzone infarction which are angiographically confirmed symptomatic cases. RESULTS: The increase in blood flow velocity (%Vm) after acetazolamide stimulation was significantly different between the both hemisphere (affected side: 24.01+/-24.44%, contralateral side: 49.39+/-19.38%, p<0.05). In patients with carotid stenosis/occlusion, vasoreactivity of the borderzone infarction cases was lower than territorial infarction cases(mean+/-SD: 12.25+/-11.20% and 29.92+/-26.42%, p=0.13), but it is not significant statistically. CONCLUSION: We concluded that TCD with acetazolamide challenge is a useful method for assessment of the adequacy of hemodynamic reserve in patients with severe stenosis or occlusive cerebrovascular disease but it is very difficult problem apply to EC-IC bypass surgery directly.

Changes of cerebral vasoreactivity in patients with acute cerebral infarction of various subtypes / 临床神经病学杂志

Objective To explore the changes of cerebral vasoreactivity(CVR) in patients with acute cerebral infarction of various clinical subtypes.Methods The 70 patients with acute cerebral infarction were divided into 3 subtypes:atherothrombotic infarction (AI)group(n=22), lacunar infarction (LI)group(n=33), cardiogenic infarction (CI)group(n=15).The mean blood flow velocity (Vm), pulse index(PI), resistance index(RI) in bilateral middle cerebral artery(MCA) were detected, and breath holding index (BHI) was measured by TCD in these patients through breath holding test. All the data were compared with the health controls. Results Compared with normal control group,the Vm,PI and RI were significantly increased (P0.05). Conclusions There are differents in CVR in patients with acute cerebral infarction of various subtypes. The damage of CVR is more obviously in AI and LI group. There is clinical significance for measurement of CVR to evaluate the haemodynamic changes in various subtype of acute cerebral infarction.

Surgical Experience of An Arteriovenous Malformation in an Eloquent Motor Area

Postoperative brain edema and/or hemorrhage is a serious problem especially arteriovenous malformations(AVM) in an eloquent area. It has ben a neurosurgical dilemma whether to surgically remove an unruptured AVM in an eloquent area. It is necessary to define the anatomic location, understand the hemodynamics, vasoreactivity of the adjacent brain parenchyma for safe removal of an AVM in an eloquent area. A successful removal of an AVM at an eloquent motor area without neurological deficit was made. We report method of localizating, angiographic anatomy, mechanism of possible hemodynamic insult related to operation.

Studies on the endothelial mechanism of simulated weightlessness on the reactivity of pulmonary artery / 解放军医学杂志

Ojective To study the endothelial mechanism of simulated weightlessness on the reactivity of pulmonary artery. Methods Experiments were conducted using 32 Wistar male rats, which were randomly divided into 2 groups: tail-suspended group and control group, 16 rats for each group. Tail-suspension for 14 days was used to simulate the effects of microgravity. The changes in responses of pulmonary artery to several vascular active agents were determined by using in vitro vessel rings perfusion technique. And the changes were determined again after the endothelium of pulmonary artery was removed. Results Compared with the control group, the contractile responses of pulmonary artery to potassium chloride (68mmol/L) and phenylephrine (PE, 10 -7 ~10 -5 mmol/L) were markedly diminished after 14 days tail-suspension, while the dilatory responses to acetylcholine (Ach, 10 -8 ~10 -6 mmol/L) were markedly enhanced. The vascular reactivity of endothelium-removed pulmonary artery rings to PE and sodium nitroprusside (SNP) did not change after 14 days tail-suspension. Conclusion The contractile responsiveness is attenuated and the dilatory responsiveness is enhanced in the rats' pulmonary arteries after simulated weightlessness. That the pulmonary artery endothelium changes in structure or function after simulated weightlessness might be an important cause of changing in the reactivity of pulmonary artery.