RESUMEN
Cerebrovascular disease may be linked with vascular autoregulation in aging. The aim of this study was to examine relation between nocturnal blood pressure (BP) fall and cerebral blood flow (CBF) changes in elderly men. The prospective 'Men born in 1914' cohort study has been in progress since 1968 and included 809 subjects. After 14 years from the last follow up, 97 subjects reached the age of 82 and underwent CBF measurement and 24 h ambulatory blood pressure monitoring. Diastolic BP at night decreased in 84 subjects with median 12.7% and increased in 13 subjects with median 3.7%. Relative diastolic BP fall at night was negatively associated to CBF in temporal and infero-parietal areas. Higher proportion of subjects with increasing systolic BP during the 14-year period was observed in the subgroup with extreme nocturnal diastolic BP dip, irrespectively of BP values or prevalence of hypertension. Extreme nocturnal diastolic BP fall in a cohort of elderly men is correlated with focal changes in CBF. Further studies could explain if increasing BP in the elderly is a cause or result of pathological autoregulation, and if antihypertensive treatment increases nocturnal BP dip.
Asunto(s)
Presión Sanguínea/fisiología , Isquemia Encefálica/etiología , Circulación Cerebrovascular , Ritmo Circadiano/fisiología , Anciano de 80 o más Años , Antihipertensivos/efectos adversos , Antihipertensivos/farmacología , Antihipertensivos/uso terapéutico , Sistema Nervioso Autónomo/fisiología , Presión Sanguínea/efectos de los fármacos , Monitoreo Ambulatorio de la Presión Arterial , Isquemia Encefálica/epidemiología , Isquemia Encefálica/fisiopatología , Circulación Cerebrovascular/efectos de los fármacos , Estudios de Cohortes , Comorbilidad , Diabetes Mellitus/epidemiología , Diástole , Humanos , Hipercolesterolemia/epidemiología , Hipertensión/tratamiento farmacológico , Hipertensión/epidemiología , Hipertensión/fisiopatología , Hipertrigliceridemia/epidemiología , Masculino , Estudios Prospectivos , Accidente Cerebrovascular/epidemiología , Suecia/epidemiología , SístoleRESUMEN
In Alzheimer's disease (AD), an association was found between autonomic dysfunction and frontal hypoperfusion in brain during orthostatic testing. To ascertain whether frontal hypoperfusion is dependent on longitudinal effects of hemodynamic disturbances, or contributes to them, we studied the relationship between the presence of orthostatic hypotension (OH) and resting cerebral blood flow (CBF) in late stages of AD. Twelve women with senile dementia of Alzheimer type (SDAT), and 15 non-demented women (mean age 82.6 years, SD 3.8 vs 81.8 years, SD 3.5) were examined with the orthostatic test. Four of 12 patients with SDAT, and 9 controls had OH (defined as systolic blood pressure fall > or = 20 mmHg). CBF was determined under resting conditions using 600 Mbq 99mTc HMPAO single photon emission computerized tomography (SPECT), and quantified in cortical areas in relation to cerebellum. In patients with SDAT and OH, CBF was lower in frontal and parieto-frontal cortical areas than in SDAT patients without OH. The former group was younger and had a shorter dementia duration. No significant differences in CBF were observed between controls with vs without OH. No differences in SDAT patients with or without OH were observed in the Berger dementia scale or Katz' ADL index. No difference in incidence of symptoms related to autonomic disturbances (diarrhea, obstipation, dysphagia, vertigo) was observed in either the SDAT or control group with regard to OH presence. We conclude that during the course of AD, OH can contribute to frontal brain changes and may exacerbate the disease. The further involvement of frontal dysfunction in aggravating blood pressure dysregulation in the elderly is discussed.
Asunto(s)
Envejecimiento/patología , Enfermedad de Alzheimer/complicaciones , Encéfalo/fisiopatología , Hipotensión Ortostática/etiología , Anciano , Anciano de 80 o más Años , Presión Sanguínea , Encéfalo/irrigación sanguínea , Encéfalo/patología , Circulación Cerebrovascular , Femenino , Lóbulo Frontal/irrigación sanguínea , Lóbulo Frontal/patología , Lóbulo Frontal/fisiopatología , Frecuencia Cardíaca , Humanos , Lóbulo Occipital/irrigación sanguínea , Lóbulo Occipital/patología , Lóbulo Occipital/fisiopatología , Lóbulo Parietal/irrigación sanguínea , Lóbulo Parietal/patología , Lóbulo Parietal/fisiopatología , Pruebas de Mesa InclinadaRESUMEN
Two radiopharmaceuticals, 99Tcm-hexamethyl propylene amine oxime (99Tcm-HMPAO) and 99Tcm-ethyl cysteinate dimer (99Tcm-ECD), are currently used to determine cerebral blood flow. 99Tcm-ECD is, by virtue of its greater stability, superseding 99Tcm-HMPAO for routine examinations. Since the clinical assessment of 99Tcm-ECD images is usually based on experience with 99Tcm-HMPAO, we used both radiopharmaceuticals to compare regional cerebral blood flow in the same individuals. Eleven healthy subjects aged 67.1 +/- 6.3 years (mean +/- S.D.) underwent 99Tcm-ECD followed by 99Tcm-HMPAO single photon emission tomography. Cerebral blood flow was quantified in cortical and central regions of interest (basal ganglia, ventricles, white matter) in relation to cerebellar uptake. The intra-subject comparison of cerebral blood flow in the cortical areas revealed higher levels of perfusion in the posterior parietal, parieto-occipital and temporo-occipital areas using 99Tcm-ECD. In contrast to the cortical areas, cerebral blood flow in the central areas was greater using 99Tcm-HMPAO, especially in the centrum semiovale, basal ganglia, frontal white matter and frontal horns. This difference in cerebral blood flow when imaging healthy individuals with 99Tcm-ECD and 99Tcm-HMPAO should be taken into account in clinical practice when changing from one radiopharmaceutical to the other.
Asunto(s)
Circulación Cerebrovascular/fisiología , Cisteína/análogos & derivados , Compuestos de Organotecnecio , Radiofármacos , Exametazima de Tecnecio Tc 99m , Anciano , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Masculino , Trastornos de la Memoria/diagnóstico por imagen , Persona de Mediana Edad , Valores de Referencia , Tomografía Computarizada de Emisión , Radioisótopos de XenónRESUMEN
The presence and functional significance of white matter lesions in the ageing brain and in dementia as well as their relation to blood pressure are often discussed. The aim of this study was to evaluate cerebral blood flow in white matter (WMCBF) and its relation to systemic blood pressure and multichannel EEG. WMCBF was measured in 24 elderly women with senile dementia of Alzheimer's type (SDAT, median age 85.5, range 68-93) and 20 age-matched controls (median age 86.0, range 79-93) using 99mTc-HMPAO single photon emission CT. A significant low WMCBF could be observed in all analysed regions in SDAT subjects compared to controls, with the greatest decline in the posterior region (parietotemporo-occipital area). Correlations between quantified EEG from the posterior regions and WMCBF were seen. Systolic blood pressure was significantly lower in the SDAT group and was positively correlated with WMCBF in the posterior and anterior brain regions. Whether low systemic blood pressure is the result of crerebral dysfunction is unclear.
Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Presión Sanguínea/fisiología , Circulación Cerebrovascular/fisiología , Electroencefalografía , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico por imagen , Femenino , Humanos , Exametazima de Tecnecio Tc 99m , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
Thirteen women with senile dementia of Alzheimer's type (SDAT) according to NINCDS-ADRDA and 21 age-matched control women, aged 75-96 years, were investigated with clinical examination, dementia rating scales and single photon emission computed tomography (SPECT) using 99mTc-hexamethylpropyleneamine oxime (HM-PAO) as a tracer of regional cortical blood flow. The aim was to study whether typical SPECT findings of SDAT were seen also in the very old having the disease for a longer period. Neuropsychological assessment with vocabulary and spatial tests was performed in the control women, and the results were divided in three subgroups, normal, borderline and abnormal. Regional perfusion values, expressed as a ratio between cortical and cerebellar HM-PAO uptake, were lower in frontal, temporoparietal and occipital cortices in SDAT patients than in controls. The SDAT patients had the lowest uptake in the posterior temporoparietal region (0.67 +/- 0.06) and the corresponding value in the controls (0.79 +/- 0.05) differed significantly, p < 0.0001. The interhemispheric ratio between right and left posterior temporoparietal regions was 0.99 +/- 0.05. Nine of the control women (43%) had pathological SPECT with hemispheric asymmetries in 6 cases and bilateral temporooccipital reductions in 3 women. The neuropsychological assessment matched the findings in 7 of these women. One of the control women was judged as pathological and 10 women as borderline according to the spatial and vocabulary tests. Four of the 10 women with borderline results had normal SPECT. The sensitivity of the assessment to detect abnormalities compared to SPECT was 78% if borderline and abnormal results were expressed as true-positive cases. The specificity was 67%.(ABSTRACT TRUNCATED AT 250 WORDS)