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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The annual incidence of strokes (all types) is estimated to be between two and four per thousand in the 55 to 64 year age-group and reaches about 15 per thousand over the age of 75 years. Population registries and hospital registries show that cerebral infarcts represent about 80% of all strokes and indicate the respective roles of the principal causes. A significant reduction in mortality related stroke in general and cerebral infarction in particular has been observed in many countries over recent decades. Hypertension constitutes the principal risk factor for ischaemic and haemorrhagic stroke. This risk varies by about 40% when the mean diastolic blood pressure varies from 5 to 10 mmHg, even in normotensive subjects. Several studies have demonstrated that treatment of moderate or severe hypertension lowers the incidence of stroke. Smoking, diabetes, chronic alcoholism (> 3 standard glasses per day), hypercholesterolaemia and raised plasma fibrinogen also constitute independent risk factors for cerebral infarction. Of the emboligenic heart diseases, non-valvular atrial fibrillation (80% of all cases of atrial fibrillation) is the most potent risk factor for cerebral infarction: subjects with this disease have a risk of cerebral infarction of approximately 5% per year. The presence of asymptomatic carotid artery stenosis is associated with an annual risk of cerebral infarction generally estimated to be between 1 and 2% which, in reality, increases with the degree of stenosis. Even in the case of tight stenosis, the risk of ipsilateral cerebral infarction remains low (< 3% per year for stenosis > 75%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Epidemiology of cerebral infarction]. 817 87

Data from the 2 major studies (ECST and NASCET) carried out to evaluate surgery of symptomatic carotid artery stenosis provided more information on the evolution (during medical treatment) of these lesions than all previous work. The essential risk, that of a cerebral infarction homolateral to the stenosis, is closely related to the degree of stenosis; for occlusions greater than 70% it was 5% annually in the ECST and 13% in the NASCET, more severe occlusions being treated in the latter study. Inversely, it was only 0.5% annually for stenoses involving less than 30% (ECST). For occlusions of between 30 and 70%, the risk has not yet been determined exactly, since the 2 studies are ongoing, but everything suggests that the risk is related to the degree of stenosis for this range also. Factors increasing this risk include: the cerebral site--and not only retinal--of the initial stenosed carotid, the ulcerative nature of the stenosis, the existence of contralateral carotid occlusion and the presence of vascular risk factors. Therapy is dependent on the evaluation of total risk factors, surgery being indicated increasingly as there is the greater high risk of stenosis. Surgery is then additional to medical treatment of vascular risk factors, mainly hypertension and antithrombotic therapy: generally aspirin and perhaps Ticlopidine.
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PMID:[Evolution of symptomatic carotid stenoses under medical treatment]. 825 40

Perioperative stroke is a devastating complication of abdominal aortic operations. Patients requiring aortic reconstruction with advanced carotid occlusive disease pose a particularly challenging management problem regarding timing of operations. All patients (n = 121) undergoing both carotid artery endarterectomy (CEA) and abdominal aortic reconstruction (AAR) within 1 year of each other between 1979 and 1989 were reviewed. The sequence of operation was analyzed to determine its effect on early and late outcome. CEA was the first operation in 99 patients (group I); AAR was performed first in 22 patients (group II). Age, gender, number, types of risk factors, and associated medical problems were similar in both groups. Indications for CEA were: transient ischemic attacks (TIAs), recent ipsilateral stroke, or high-grade asymptomatic carotid artery stenosis exceeding 80%. Indications for aortic operation included: abdominal aortic aneurysm, aortoiliac occlusive disease, and combined aortic and renovascular disease. There were five perioperative strokes, two in group I (2%) and three in group II (14%) (p < 0.04). All strokes occurred after AAR. There were five perioperative deaths (4%), four in group I (4%) and one in group II (5%). Overall survival was significantly greater in group I compared to group II (p < 0.04); 5-year survival was 77% and 51%, respectively. Multivariate analysis demonstrated age, hypertension, and diabetes to adversely affect survival; CEA as the first procedure, however, had a protective effect. Importantly, eight strokes occurred in group I in late follow-up, but only one was ipsilateral to the CEA. We conclude that CEA in selected patients who require AAR is safe, and, when performed prior to abdominal aortic repair, reduces perioperative stroke and may improve long-term survival.
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PMID:Advanced carotid disease in patients requiring aortic reconstruction. 835 6

Correction of high grade carotid artery stenosis may result in cerebral hyperperfusion because of defective vascular autoregulation. Thus, transcranial Doppler was used to determine mean arterial flow velocity (Vmean) of the middle cerebral artery in 95 patients before and after carotid endarterectomy. Attention was focused on postoperative episodes of ipsilateral headache and hypertension. Symptoms of cerebral hyperperfusion lasted for 3 (1.5-5) h (median and range) in nine patients, and for 12 (8-14) days in nine other patients. Of these later patients, two developed seizures on the 5th and 6th postoperative day, respectively. The mean pressure difference across the stenosis was 31 (0-63) mmHg in the symptomatic group (n = 18) as opposed to only 10 (0-60) mmHg in the asymptomatic group (n = 77) (p < 0.01). In the 18 patients with headache after surgery, ipsilateral Vmean increased to 177 (130-332)% of the preoperative value (p < 0.0001), while the contralateral Vmean remained unchanged. After blood pressure was reduced in symptomatic patients with labetalol, ipsilateral Vmean decreased from 92 (69-124) to 56 (32-93) cm s-1 (p < 0.0001) as systemic arterial pressure decreased from 101 (80-128) to 88 (60-103) mmHg, with no change in contralateral Vmean. Normalisation of Vmean via reduction of arterial pressure ended episodes of headache and seizure in symptomatic patients. Thus, in patients who developed post-endarterectomy hyperperfusion, these findings clearly demonstrated that ipsilateral middle cerebral artery mean flow velocity was pressure dependent. This substantiates the hypothesis of defective autoregulation in the ipsilateral hemisphere after carotid endarterectomy, and in turn demonstrates an immediate cessation of symptoms with reduction of arterial pressure even in normotensive patients.
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PMID:Defective cerebrovascular autoregulation after carotid endarterectomy. 835 91

Carotid angiography was carried out in 21 Chinese patients with acute capsular infarcts; all had had a previous ipsilateral transient ischaemic attack (TIA) or reversible ischaemic neurological deficit (RIND) during the preceding 6 months. Sixteen (group 1) showed lacunar capsular infarcts, and 5 (group 2) either "giant lacunae" or "striatocapsular infarcts". Angiography showed that 81% of group 1 and all group 2 patients had ipsilateral severe stenosis or occlusion of either the M1 segment of the middle cerebral artery or the internal carotid artery. Ten group 1 patients and 3 group 2 patients also had contralateral intra- or extracranial carotid artery stenosis. Apart from hypertension, other risk factors such as hyperfibrinogenaemia, polycythaemia, and low HDL-cholesterol level seem to play a role. Haemorheological abnormalities in the presence of atherostenosis at the orifice of lenticulostriate arteries and/or artery-to-artery embolism might be the cause of infarcts in the majority of the patients. A fifth of patients had recurrent large ipsilateral infarcts. Thus capsular lacunar syndromes with prior ipsilateral TIA or RIND are not as benign as previously thought, and they should indicate more intensive studies including cerebral angiography, and more vigorous therapy.
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PMID:Large vessel disease in Chinese patients with capsular infarcts and prior ipsilateral transient ischaemia. 845 17

Genetic influences in cerebrovascular disease (CVD) may act either independently or by predisposing to, or modulating, the effect of risk factors such as hypertension. Factors involved in the pathogenesis of atherosclerosis, thrombosis and vasoconstriction are important in CVD. The angiotensinogen gene has recently been linked with essential hypertension in affected sibships and a particular polymorphism in exon 2 of the angiotensinogen gene, a threonine to methionine substitution at position 235 (M235T), has been associated with pre-eclampsia and hypertension. In this study we examined the relation of M235T polymorphism to cerebrovascular disease and carotid atheroma in 100 consecutive Caucasian patients with internal carotid artery territory ischaemia (TIA or stroke), presenting to a carotid ultrasound service. Forty five age-matched controls (mostly patients' spouses) were also studied. Hypertension was defined as current treatment with anti-hypertensive agents, or SBP > 160 mm Hg or DBP > 95 mm Hg. Twelve of 100 cases (12%) and eight of 45 controls (12%) were homozygous for the T235 allele. T:M allele ratios were 0.34:0.66 in cases and 0.34:0.66 in controls. There was no relation between the polymorphism and either internal carotid stenosis or common carotid artery intima-media thickness. In the cases, mean percentage internal carotid artery stenosis was TT 18.3 (SD 18.7)%, MT 38.0 (27.1)% and MM 36.8 (30.2)%. Mean intima-media thickness was TT 0.87 (0.18) mm, MT 0.95 (0.34) mm and MM 0.88 (0.23) mm. There was no relation between the polymorphism and hypertension (TT 11 of 100 cases, six of 45 controls).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lack of association between angiotensinogen polymorphism (M235T) and cerebrovascular disease and carotid atheroma. 852 90

The association of electrocardiographic left ventricular hypertrophy (ECG-LVH) (212 subjects) and haemodynamically significant internal carotid artery stenosis (ICAS) (27 subjects) with isolated systolic hypertension (ISH), mixed hypertension (MHT) and isolated diastolic hypertension (IDH) was studied in untreated elderly patients. Subjects were those aged 67-86 years, drawn from a community screening programme for hypertension in Wales. The prevalence of ECG-LVH with or without repolarisation abnormalities was higher in subjects with ISH (16.6%) than in subjects with mixed hypertension (11.6%, NS). Partial correlation of SBP, DBP, voltage of lead I and SV1+RV5 for each hypertensive subtype showed a consistent positive correlation of DBP with the voltage of lead I and SV1+RV5 in all the subtypes except with the voltage of lead I in IDH subjects. In MHT, the SBP was inversely related to both the voltage of R-wave in lead I and SV1+RV5 (P < 0.03). In IDH, the SBP was positively correlated with the voltage of R-wave in lead I and inversely with SV1+RV5. Atheromatous plaque was present in 40 of 54 (74.1%) internal carotid arteries investigated. The homogeneous type of plaque was predominant in ISH (67%). Heterogenous type of plaque was predominant in the MHT group (50%) and IDH group (43%). The normotensive group did not show any predilection to any morphological type. Plaque was invariably present in the case of ISH, chi 2 = 12.29, 0.1 > P > 0.05. There was more smooth plaque surface in normotensives (79%) and more rough or pitted plaque surface in hypertensives (all types), chi 2 = 6.51, 0.1 > P > 0.05. All normotensives and IDH subjects had non-haemodynamically significant stenosis. Haemodynamically significant stenosis was found in cases of ISH (25%) and MHT (7%); chi 2 = 7.66, 0.1 > P > 0.05. ECG-LVH and haemodynamically significant internal carotid artery stenosis were more commonly found in subjects with ISH than in subjects with MHT. Further studies with larger numbers of patient in each hypertensive subtype would be desirable to confirm these observations.
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PMID:Is isolated systolic hypertension in the elderly more associated with left ventricular hypertrophy and significant carotid artery stenosis than mixed hypertension and isolated diastolic hypertension? 857 96

The risk of stroke related to asymptomatic carotid artery stenosis is known to be increased in high-grade or rapidly progressive stenosis. Information of the prevalence in the general population is required for the recommendation of screening methods to detect patients needing prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid and vertebral artery obstructions by means of Doppler sonography in 529 asymptomatic Russians (m: 343, f: 186; 36-84 years, mean: 58.4 years) living in Moscow city. Internal carotid artery obstructions of more than 50% stenosis were present in 22 (= 4.2%) subjects, 8 of them (1.5%) had bilateral lesions. Appropriate abnormal findings in vertebral arteries were found in 11 (= 2.1%) subjects, in 1 of them bilaterally. Affection of both the carotid and the vertebral arteries was noted in 4(= 0.8%) individuals. There were no sexual differences. The risk factor which correlated most significantly with cervical arterial lesions was hypertension. Carotid lesions were also significantly associated with age and smoking, but not with diabetes or hyperlipoproteinemia. The prevalence of cervical artery stenoses was found to be lower than in western reports, which may be due to different technical equipment and different study design.
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PMID:Asymptomatic cervical artery stenoses in Moscow. 873 40

We determined plasma activity of the isoenzymes of beta-hexosaminidase (Hex) in 151 patients with cerebral infarction, since earlier findings have shown a relation between Hex isoenzymes and risk factors for vascular disease in normal subjects. Compared with 206 control subjects, an elevated level of plasma Hex isoenzymes was found in patients with cerebral infarction, particularly females. However, there was no relation to the clinical subtypes of diagnosis or to the presence of any risk factors for vascular disease, such as carotid artery stenosis, major potential cardio-embolic risk factors on echocardiography, hypertension, heart disease, diabetes mellitus or tobacco smoking. Instead, our findings indicate that Hex isoenzymes in patients with cerebral infarction are more influenced by the level of serum aspartate aminotransferase and blood glucose. The main conclusion is that the liver function as reflected by the level of liver enzymes and glucose metabolism are the major determinants of Hex isoenzymes in plasma.
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PMID:Plasma beta-hexosaminidase isoenzymes A and B in patients with cerebral infarction. 891

We studied the relationship between infarct size and degree of internal carotid artery stenosis in 227 stroke patients without a source of embolism in the heart, who had a CT-verified territorial brain infarct. We used logistic regression analysis adjusting for differences between groups in co-associated variables such as age, sex, hypertension, diabetes mellitus, and a history of ischaemic heart disease. Ipsilateral carotid stenosis greater than 50% was more strongly associated with large than small infarcts; adjusted odds ration [(a)OR]: 4.56; 95% confidence interval (CI): 1.21-17.2; P = 0.02. For ipsilateral carotid occlusion the association was even stronger--(a)OR: 36.80; 95% CI: 2.54-533; P = 0.007. When large infarcts were compared with infarcts of small and moderate size together the ORs were 2.29, 95% CI 1.14-4.58 and 2.57, 95% CI 1.17-5.67 for carotid stenosis or occlusion, respectively. Our data show a relationship between greater than 50% carotid stenosis or occlusion and large brain infarcts. We suggest that haemodynamic impairment may contribute to infarct size in territorial infarcts of non-cardiac origin.
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PMID:The size of territorial brain infarction on CT relates to the degree of internal carotid artery obstruction. 896 8


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