PubMed Health⌕ Search

Biomedical subjects

K F Mortel

Publications and source records attributed to K F Mortel.

At least 19 recordsLinked to original sources
PubMed1996

Prospective study of vascular events and cerebral perfusional changes following transient ischemic attacks.

A prospective case-control study was carried out to clarify associations of cerebral transient ischemic attacks (TIAs) and other stroke risk factors with progression and exacerbation of cardiovascular and cerebrovascular disorders; 243 neurologically normal controls and 123 TIA patients without prior history of stroke were followed up for a mean interval of 4.4 years of TIA patients, 26 (21%) developed other events (excluding recurrent TIAs); 10 died of vascular causes (8.1%). Of controls, 44 (18%) developed events; 13 died of vascular causes (5.4%) and 3 from cancer. TIA patients were at 2.3 times greater risk than normal controls for stroke or death from vascular causes. They were predominantly male with significantly higher associations of risk factors for stroke, including hypertension, heart disease, diabetes mellitus, smoking, hyperlipidemia, alcohol consumption, and limited education. Controls developing vascular events compared with controls who did not were older, more frequently male, and with greater incidences of heart disease. TIA patients had lower rates of cerebral perfusion compared with controls that persisted throughout the study, with similar rates of decline related to aging among both groups. Among TIA patients, stroke risk factors were more prevalent than among controls. The longer their duration, the greater the incidence and the more rapid the rate of severe, often fatal cardiovascular complications.

Age Factors↗
PubMed1995

Prospective CT confirms differences between vascular and Alzheimer's dementia.

BACKGROUND AND PURPOSE: Cognitive test performances were correlated prospectively with changes in cerebral CT measurements of atrophy, infarct volume, ventricular enlargement, local tissue density, and local perfusion to contrast annual rates of changes among patients with ischemic vascular dementia (IVD) or dementia of the Alzheimer type (DAT). METHODS: The cerebral atrophic index (ATI; ratio of cerebrospinal fluid or infarcted brain to intracranial volume), infarct volume ratio, ventricular volume ratio (VVR; ventricular volume/intracranial volume), cortical and subcortical gray and white matter local perfusion (local cerebral blood flow [LCBF]), and local Hounsfield unit (HU) density were measured concurrently and compared longitudinally with Cognitive Capacity Screening Examinations (CCSE) scores among 24 treated IVD (age, 68.2 +/- 9.7 years; follow-up, 42 +/- 27 months) and 24 DAT patients (age, 74.2 +/- 6.2 years; follow-up, 30 +/- 19 months). RESULTS: IVD annual changes were as follows: CCSE, +1.2 +/- 5.9; ATI, +2.1%/y; VVR, +3.2%/y; and LCBF in the subcortical basal ganglia, -0.74 mL.100 g-1.min-1.y-1 (-1.8%/y). DAT annual changes were as follows: CCSE, -1.8/y; ATI, +8.1%/y; VVR, +9.6%/y; cortical LCBF, -2.0 mL.100 g-1.min-1.y-1 (-5.2%/y); LCBF in the basal ganglia, -3.0 mL.100 g-1.min-1.y-1 (-6.7%/y); white matter LCBF, -0.75 mL.100 g-1.min-1.y-1 (-4.1%/y); and all cortical tissue densities, -0.83 HU/y (-2.1%/y). In IVD, multiple regression analyses correlated cognitive changes directly with (1) recurrent silent infarctions and (2) bidirectional changes of perfusions within frontal white matter, thalamus, and internal capsules. In DAT, cognitive declines correlated with cerebral atrophy and cortical hypoperfusion related to frontotemporal and parietal cortical polioaraiosis (decreased gray matter tissue densities). CONCLUSIONS: In IVD, recurrent strokes were not observed clinically during risk factor control, and antiplatelet therapy and cognitive impairments improved or stabilized. In DAT, cognitive performance relentlessly declined. Ischemic pathogenesis for vascular dementia is supported by the following: (1) cognitive declines correlate directly with recurrent "silent" strokes, and (2) bidirectional cognitive changes correlate directly with frontal white matter, thalamic, and internal capsular perfusional changes.

Aged↗
PubMed1995

Lack of postmenopausal estrogen replacement therapy and the risk of dementia.

Estrogen replacement therapy (ERT) and associated risks for ischemic vascular dementia (IVD) and dementia of the Alzheimer's type (DAT) among postmenopausal women were investigated by determining whether ERT was differently distributed among control subjects than among subjects with dementia. Subjects included 93 with probable DAT, 65 with probable IVD, and 148 normal control subjects. The proportion of control subjects on ERT was almost 2:1, and this ratio holds for both dementia groups. Logistic regression suggests lack of ERT is associated with increased risk for dementia among elderly women. ERT may eventually prove to be a useful prophylactic agent for reducing risk of DAT and IVD among postmenopausal women.

Aged↗
PubMed1995

Cerebral density and perfusion measured among heart disease patients with and without stroke.

This investigation was designed to clarify the chronic effects of cardiogenic emboli on cerebral perfusion and tissue densities within remaining noninfarcted brain. Local cerebral perfusion and tissue densities were measured by xenon-contrasted CT scanning and compared by cross-sectional designs among normal volunteers without heart disease (Group C, n = 44), normal volunteers with heart disease (Group N, n = 20), patients with heart disease and lacunar infarctions (Group L, n = 31) and patients with heart disease associated with cardiogenic cerebral embolism (Group E, n = 12). In Group E, remaining cortical and subcortical gray and white matter perfusion were reduced compared to Groups C and N (p = 0.01), but did not differ from Group L, who had similar profiles of risk factor for stroke. In Group E, perfusion was reduced within the thalamus ipsilateral to cortical infarctions (p < 0.05). There were no differences in remaining tissue densities between Groups E and L. It is concluded that reduced cerebral perfusion in noninfarcted regions among patients with cardiogenic emboli appears to be related to atherosclerosis of small cerebral vessels in a similar manner to patients with lacunes, but thalamo-cortical disconnections also contribute to cerebral hypoperfusion.

Adult↗
PubMed1994

Cognitive declines correlate with decreased cortical volume and perfusion in dementia of Alzheimer type.

Cerebral CT changes are correlated with cognitive declines among 18 patients with probable dementia of Alzheimer type (DAT) (7 men, 11 women, mean age 75.4 years) and are compared for control purposes with similar measures among 18 age-matched normal volunteers (8 men, 10 women, mean age 73.7 years). Mean follow-up intervals are 28.6 months for DAT and 27.0 months for controls. For DAT, annual rates for ventricular volume enlargement are +9.2% and for cortical atrophy are -2.1%. Annual reductions in regional cerebral perfusions per 100 g brain/min, are: total cortex -1.1 ml, frontal -1.2 ml, temporal and parietal -0.9 ml, basal ganglia -1.6 ml, thalamus -2.5 ml, total white matter -0.6 ml, frontal white matter -0.7 ml. At entry evaluation, compared to normals, DAT patients had reduced CT densities in white matter, but not in cortex. Nevertheless, cortical CT densities declined progressively at annual rates of -0.72 Hounsfield units (HU), but remained constant in white matter. Annual point score declines for Cognitive Capacity Screening Examinations were -2.0 and for Mini Mental State: -2.8. Controls showed no cognitive change. Multiple regression analyses correlate cognitive declines with: (1) reductions in perfusion within parietal cortex (p = 0.015), (2) decreases in cortical volume (p = 0.019), and (3) decreases in HU within subcortical gray matter (p = 0.007).

Aged↗
PubMed1994

Problems encountered with longitudinal neurological, psychometric and cerebral CT imaging among stroke data bank patients with dementia.

41 patients (30 men, 11 women, mean age 65.3 +/- 9.7 years) with probable ischemic vascular dementia diagnosed according to stated clinical criteria at least 3 months after hospital discharge and among a few nonhospitalized subjects with thorough clinical, neurovascular and neuroimaging workup have been followed for the past 7 years with serial measures of neurological and cognitive status and cerebral blood flow using stable xenon-enhanced CT. Cognitive impairments correlated with cerebral ischemia rather than CT measurements of infarcted brain volume. A minimum of one follow-up was required and follow-up intervals ranged from 4 months to 6.6 years (mean 3.4 +/- 1.6 years). 9 patients (22.0%) were lost to follow-up, 4.9% died, 9.8% became incapacitated by additional strokes, 2.4% by cancer and 4.9% moved away. Cross-sequential designs adjust for problems of attrition. Mortality rates of 1.4%/year during 1986-1993 are significantly lower than 2.0%/year between 1983 and 1986. Declines in mortality are attributed to control of risk factors and antiplatelet treatment of atherosclerotic cerebral vascular disease and anticoagulant treatment of patients with cardiogenic embolism.

Aged↗
PubMed1994

Prospective studies of cerebral perfusion and cognitive testing among elderly normal volunteers and patients with ischemic vascular dementia and Alzheimer's disease.

To compare longitudinal changes of cerebral perfusion (CBF) and cognitive status in two common forms of dementia in the elderly, 42 patients with ischemic vascular dementia (IVD), 44 patients with dementia of the Alzheimer type (DAT), and 120 elderly normal volunteers were evaluated prospectively over a mean interval of 3.35 years. Subjects were at least age sixty, (mean age 71.1). Mean bihemispheric cerebral blood flow and cognitive test scores of control subjects were significantly higher than those of both demented groups at entry and remained so. After adjustment for initial CBF, course over time was similar for all groups. Group variability was similar for CBF but not for cognition. Both IVD and DAT patients were more variable than controls but similar to each other. Throughout, DAT patients showed greater cognitive impairments than IVD patients. Cognitive impairments stabilized among IVD patients treated by control of risk factors, antiplatelet or anticoagulant therapy but declined progressively among DAT patients.

Age Factors↗
PubMed1993

Analysis of familial and individual risk factors among patients with ischemic vascular dementia and Alzheimer's disease.

UNLABELLED: The purpose of this study was to determine relative contributions of first-degree familial and individual risk factors to clinical manifestations of two major age-related dementias. The authors interviewed 183 patients with dementia of the Alzheimer's type (DAT) and 137 patients with ischemic vascular dementia (IVD) together with family members and caregivers. Information was also obtained from medical records and collateral sources as required. Risk factor data within a predictive model for differentiating the two dementias were evaluated. There was a greater incidence of family history of degenerative and dementing neurologic disorders in DAT than in IVD. Both groups were equivalent for family histories of cerebrovascular disease. Despite familial equivalence, patients with IVD had a greater individual incidence of risk factors for cerebrovascular disease. Analysis by gender revealed three observations. Among DAT patients, family history for degenerative and dementing neurologic disorders proved to be significantly greater among women than among men. This risk factor did not, however, predict individual diagnoses for DAT. Women with IVD were more likely to have a family history of cancer than men. Multiple regression analyses revealed that reduced educational levels in women predicted greater liability for IVD than for DAT. Hypertension, heart disease, and diabetes mellitus were all risk factors for IVD, but not for DAT. CONCLUSIONS: Individual and familial historical data provide useful information concerning identification, pathogenesis, prevention, and treatments for vascular dementia but little predictive information for identifying patients with Alzheimer's disease.

Adult↗
PubMed1992

Patterns of cerebral hypoperfusion compared among demented and nondemented patients with stroke.

BACKGROUND AND PURPOSES: No reports are available that compare local cerebral perfusion among groups of patients suffering from multiple cerebral infarctions with and without cognitive impairments. The present study was designed to correlate changes in regional cerebral perfusion that may lead to dementia among patients with multiple cerebral infarctions by comparing measurements of local cerebral blood flow. METHODS: Local perfusion was measured using xenon-contrasted computed tomographic scanning among two groups of patients who had suffered from multiple cerebral infarctions: Group D (n = 12) were demented and had severe cognitive impairments, and group I (n = 11) were cognitively intact. Results were compared with similar measurements among neurologically and cognitively normal, age-matched volunteers (group N, n = 16). RESULTS: Mean local perfusion values were reduced among both groups with cerebral infarctions but to a more marked degree in group D (p less than 0.05). Perfusion of cerebral white matter was diffusely and severely reduced in group D (p less than 0.05) but was mildly reduced only in frontal and capsular white matter in group I (p less than 0.05). Perfusion of cerebral cortex was reduced in frontal (p less than 0.01) and temporal (p less than 0.01) regions among both groups but to a significantly greater degree in group D subjects (frontal, p less than 0.05; temporal, p less than 0.01), who also showed hypoperfusion of the occipital cortex (p less than 0.05), apparently because of underlying leukoaraiosis and cortical disconnections. Perfusion of the basal ganglia was reduced to the same degree among both groups of stroke patients (p less than 0.01). CONCLUSIONS: Leukoaraiosis with white matter hypoperfusion appears to be an important determinant for cognitive impairments among patients with multiple cerebral infarctions.

Aged↗
PubMed1990

Effects of medical and surgical treatment on cerebral perfusion and cognition in patients with chronic cerebral ischemia.

The effects of medical treatment with and without cerebral revascularization procedures on cognition and cerebral blood flow were compared among 36 patients with extracranial occlusive cerebrovascular disease and cognitive impairments. Three comparable groups were studied. The first group (N = 18) received only medical treatment by control of risk factors for stroke (including hypertension, diabetes, and hyperlipidemia) and antiplatelet aggregant medication. The second group (N = 10) had the same medical treatment plus superficial temporal-to-middle cerebral artery bypass, and the third group had the same medical treatment plus carotid endarterectomy. Regional cerebral blood flow and cognition were monitored in all three treatment groups over a 3-year interval. All groups showed stabilization without expected rates of decline for both cerebral blood flow and cognition, but no statistically significant differences emerged among the treatment groups.

Aged↗
PubMed1990

Diabetes mellitus as a risk factor for stroke.

To evaluate the relative potency of diabetes mellitus as a risk factor for stroke, the relative frequency of stroke symptoms was compared among cohorts with and without diabetes. Stroke symptoms were classified as atherothrombotic cerebral infarctions, transient ischemic attacks, reversible ischemic neurologic deficits, and multi-infarct dementia. The groups were compared according to the occurrence of these symptoms, and both cross-sectional and longitudinal designs were used to study 293 consecutive patients referred to this laboratory and to contrast groups with and without diabetes. Hypertension, heart disease, and stroke symptoms and signs were more frequent among diabetics than among age-matched nondiabetics. Among diabetics, strokes occurred at an earlier age and were more common among men. Regression analyses assigned diabetes second to hypertension as a risk factor for stroke, followed by heart disease and smoking. Diabetes associated with hypertension or hyperlipidemia added significantly to stroke risk. Initially, cerebral blood flow values and cognitive test scores were equivalent among diabetics and nondiabetics; after 3 years, cognition became significantly impaired among diabetics, despite better maintenance of cerebral blood flow among treated diabetics compared with nondiabetics. Diabetes acts to compound risk for stroke not only by promoting cerebral atherogenesis but also by aggravating other risk factors including hypertension, heart disease, and hyperlipidemia.

Age Factors↗
PubMed1990

After reaching retirement age physical activity sustains cerebral perfusion and cognition.

Among neurologically normal volunteers approaching age 65 with an option for retirement, a four-year prospective longitudinal study was designed to examine effects of different levels of physical activity on cerebral perfusion by between-group comparisons. After the fourth year, cognitive performance was also tested. Three groups were compared, each composed of 30 elderly volunteers, assigned as follows: Group 1, who continued to work; Group 2, who retired but participated in regular physical activities; and Group 3, who retired but did not participate in regular, planned physical activities. Retirees who elected to become physically inactive exhibited significant declines in cerebral blood flow (CBF) throughout four years of follow-up. Those who continued to work or retirees who elected to participate in regular activities sustained more constant CBF levels. Active retirees and those who continued to work also scored better on cognitive testing after the fourth year of follow-up compared to inactive retirees.

Aged↗
PubMed1989

Randomized clinical trial of daily aspirin therapy in multi-infarct dementia. A pilot study.

Seventy multi-infarct dementia patients were randomized into an aspirin-treated group and an untreated control group for an exploratory investigation to determine any effects of 325 mg aspirin daily on cognitive performance. The control group did not receive placebo but evaluations were carried out in a blinded manner. The index group (N = 37, mean age 67.1 years) received 325 mg of aspirin by mouth once daily while the control group (N = 33, mean age 67.6 years) was followed and treated in a similar manner except that they received no aspirin. Both groups had comparable risk factors for stroke, which were treated similarly, as well as comparable initial cerebral blood flow values, as measured by the 133xenon inhalation method, and initial scores on Cognitive Capacity Screening Examination testing. Patients were evaluated at intervals of one year. Significant improvements were demonstrated for cerebral perfusion values (P less than .0001) and cognitive performance scores (P less than .0001) among aspirin-treated patients compared to untreated controls at each of three annual follow-up evaluations. Both men and women benefited from aspirin therapy and their quality of life and independence appeared to be improved, which was not apparent in the control group. Daily aspirin appears to improve or stabilize declines in cerebral perfusion and cognition among patients with multi-infarct dementia.

Aged↗
PubMed1989

Reducing hypertriglyceridemia in elderly patients with cerebrovascular disease stabilizes or improves cognition and cerebral perfusion.

Effects of lowering serum triglyceride levels were investigated among 44 elderly hypertriglyceridemic patients with risk factors for stroke, reduced cerebral perfusion, and a history compatible with symptomatic occlusive cerebrovascular disease. Patients were randomly assigned to either treatment with gemfibrozil, a lipid-lowering agent, or control conditions. Subjects in both groups were instructed to follow a diet recommended for lowering serum lipid levels, while the treatment group was additionally administered 600 mg daily of gemfibrozil. Subjects assigned to the treatment group (n = 22) showed significant reductions in serum triglyceride levels (p less than .0005). Control subjects (n = 22) did not show any significant changes in serum triglyceride levels. There were also no significant changes in total cholesterol levels in either group. Analyses of values for mean bihemispheric gray matter cerebral blood flow measured by the xenon 133 inhalation method and cognitive scores tested by the Cognitive Capacity Screening Examination indicated that gemfibrozil-treated patients maintained significantly higher levels of cerebral perfusion and cognitive performance than untreated controls did. Regression analyses for different treatment intervals indicated that both cerebral blood flow and cognition showed linear improvements that correlated directly with the duration of treatment. Lowering triglyceride levels in hyperlipidemic subjects appears to benefit cerebral perfusion and cognitive performance after four to six months.

Cerebrovascular Circulation↗
PubMed1988

Aetiological considerations and risk factors for multi-infarct dementia.

One hundred and seventy five multi-infarct dementia (MID) patients were evaluated for risk factors for stroke as well as for the types of cerebrovascular lesions that were present. The incidence of associated risk factors for stroke were as follows: hypertension (66%), heart disease (47%), cigarette smoking (37%), diabetes mellitus (20%), moderate alcohol consumption (19%) and hyperlipidaemia (21%). The most frequently occurring type of lesions were multiple lacunar infarctions of the brain (43%). These were combined with other types of stroke in an additional 21%. Atherosclerotic occlusive disease of the carotid and vertebrobasilar arteries occurred alone in 18% and was associated with other types of stroke in another 25%. Embolic cerebral infarctions were present alone in 8% and were combined with other types of stroke in 15%. MID was more frequent in men (62%) than women (p less than 0.002). Mean bihemispheric gray matter cerebral blood flow (CBF) values showed a fluctuating course and when results were pooled and compared between different types of MID, extracranial occlusive disease and/or multiple lacunar infarctions resulted in lowest CBF values. The location of cerebral infarctions was more importantly related to cognitive impairments than was the total volume of infarcted brain. Mortality rates among 125 MID patients followed for 31 months has been 5%. Correct clinical classification of the types of cerebrovascular lesions was confirmed in three necropsied cases.

Aged↗
PubMed1988

Cognition and cerebral blood flow fluctuate together in multi-infarct dementia.

Longitudinal measurements of cognitive ability measured by serial testing using the Cognitive Capacity Screening Examination (CCSE) were correlated with cerebral blood flow (CBF) throughout (mean +/- SD) 19.9 +/- 12.6 months among 57 patients with multi-infarct dementia, 17 with dementia of the Alzheimer's type, 10 with both, and among 32 age-matched elderly normal controls. Longitudinal CCSE and CBF measurements among controls yielded stable normative values. Reduced mean CCSE scores correlated directly with CBF reductions in patients with multi-infarct dementia (p less than 0.0005) and dementia of the Alzheimer's type (p less than 0.028). Patients with multi-infarct dementia had CCSE scores with retest variability exceeding those of controls (p less than 0.001) and of patients with dementia of the Alzheimer's type (p less than 0.003). CCSE scores and CBF changed together 78.6% (p less than 0.001) of the time in patients with multi-infarct dementia compared with 66.2% of the time (p less than 0.01) in those with both, 62.9% of the time (p less than 0.05) in those with dementia of the Alzheimer's type, and 47.7% of the time (NS) in controls. Further analyses indicated that changes in CCSE scores and CBF were predominantly progressive declines in patients with dementia of the Alzheimer's type, whereas the changes were more bidirectional (both increases and decreases) in patients with multi-infarct dementia; these differences were also significant. Results support the diagnostic usefulness of the Hachinski ischemic scale and confirm that both cognition and CBF fluctuate together among patients with multi-infarct dementia, whereas patients with dementia of the Alzheimer's type exhibit a more stable course, with progressive declines in cognition and CBF.

Aged↗
PubMed1987

Hyperlipidemia is a risk factor for decreased cerebral perfusion and stroke.

Possible effects of chronically elevated serum cholesterol and triglyceride levels on measurements of cerebral blood flow were investigated by between-group comparisons of individuals, with and without hyperlipidemia, among 56 neurologically normal elderly volunteers and among 102 age-matched patients with symptoms of transient ischemic attacks (TIAs). Results demonstrated significantly higher levels of serum cholesterol and triglyceride among the TIA patients compared with randomly selected age-matched normal controls of similar educational and environmental backgrounds. Cerebral blood flow levels were reduced among groups of TIA patients with elevated levels of either cholesterol or triglycerides compared with the TIA patients with normal lipid levels. Similar trends were seen among normal volunteers, but these did not reach levels of statistical significance because of the limited numbers available. Analysis of frequency distributions for risk factors other than hyperlipidemia indicated that hypertension, atherosclerotic heart disease, diabetes mellitus, and cigarette smoking were also more prevalent among TIA patients than among age-matched normal controls.

Aged↗