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Query: UMLS:C0917798 (cerebral ischemia)
 17,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On extensive clinical monitoring of nocturnal oxygen saturation (Minolta Pulsox 7) we observed three groups with an increased risk of nocturnal hypoxemia. The hypoxemia was classified in terms of severity, frequency and duration into six groups of findings. The degree of oxygen desaturation was positively correlated to the severity of disease. In the group of patients with heart failure (NYHA III-IV) (n = 13) four had severe hypoxemia, and a history of previous cardiac infarction; three of them wore a pacemaker. Decrease in saturation after acute cerebral ischemia was seen in particular in patients with oropharyngeal disorders (dysphasia and dysphagia). In the group with suspected myocardial infarction (n = 16) we measured frequent short drops in saturation in ten patients, eight of whom were heavy snorers. Because of its simplicity, non-invasiveness and high information yield, especially in acute patients, pulse oximetry is important for clinical diagnosis, with immediate consequences for many patients.
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PMID:[The value and consequences of nocturnal pulse oximetry in severe heart failure, suspected myocardial infarct and acute cerebral ischemia]. 260 50

Atherosclerotic lesions obstructing the external carotid artery are generally disregarded in the evaluation of patients with symptoms of cerebral ischemia; nevertheless, in the presence of occlusion of the ipsilateral or of both the internal carotid arteries, external carotid artery endarterectomy may be indicated, in order to increase the flow to the brain through collaterals. A lesion of the external carotid artery may be the source of retinal emboli; patients may benefit from surgical treatment of the lesion. The Authors of the present paper operated on 6 such patients, from a total of 230 carotid bifurcation endarterectomies performed in the period between January 1982 and March 1988. Morbidity and mortality were nil and 5 of the 6 patients are free of symptoms after a mean follow-up period of 23 months. One patient died 2 months after surgery due to a myocardial infarction. On the basis of this experience, the Authors discuss indications, surgical techniques and results of the surgical treatment of lesions obstructing the external carotid artery.
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PMID:Surgical treatment of lesions obstructing the external carotid artery. 274 28

In chronic hypertension, the lower limit of autoregulation of cerebral blood flow (CBF) is shifted towards high blood pressure with a consequent impairment of the tolerance to acute hypotension. Despite this, antihypertensive treatment in the great majority of patients prevents stroke and the risk for treatment-induced cerebral ischemia is only real in a limited number of clinical settings such as malignant hypertension, hypertension in the elderly, and hypertension associated with acute stroke. During long-term treatment adaptive hypertensive changes in CBF autoregulation may be reversible, especially in young patients. Drugs used for emergency lowering of blood pressure may be classified into four groups according to their effect on CBF and intracranial pressure: (1) drugs with no pharmacological action in the cerebral circulation; (2) cerebral vasodilators; (3) alpha-adrenergic and ganglionic blockers; and (4) angiotensin-converting enzyme (ACE) inhibitors. Oxygen saturation in the jugular venous blood is of the order of 60% to 70% and is considerably higher than in the coronary sinus. It is hypothesized that this oxygen reserve enables the brain better than the heart to take hemodynamic advantage of pressure lowering without risking tissue ischemia. This may explain why antihypertensive treatment prevents stroke but not myocardial infarction. Acute hypertensive encephalopathy is probably caused by failure of autoregulatory vasoconstriction with focal or generalized dilatation of small arteries and arterioles. This is associated with a high CBF, dysfunction of the blood-brain barrier, and the formation of brain edema that is thought to cause the clinical symptoms.
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PMID:Cerebral blood flow and its pathophysiology in hypertension. 275 6

Nicardipine, a calcium antagonist of the 1:4 dihydropyridine type, has been used to treat angina and hypertension and is currently being examined as an agent for treating ischemia of cerebral and myocardial tissue. Nicardipine shows high affinity for the dihydropyridine binding site (pKi = 9.7) and inhibits the L-type calcium ion channel as demonstrated by its ability to decrease the calcium ion-dependent action potential dose-dependently in ventricular papillary muscle (pIC50 = 7.15). Nicardipine shows greater potency in inhibiting the response of vascular smooth muscle (pIC50 = 8.20) than that of cardiac muscle (pIC50 = 7.15). The nicardipine selectivity for vascular smooth muscle is greater than that shown by other dihydropyridine calcium antagonists such as nifedipine and accounts for the efficacy of nicardipine in the treatment of angina and hypertension. Various mechanisms have been proposed to account for the beneficial action of nicardipine in treating animal models of cerebral ischemia and myocardial infarction. For example, it has been suggested that (1) nicardipine has a specific membrane-stabilizing effect on cell membranes, (2) the compound blocks certain sodium channels, (3) it may become concentrated in ischemic cells, or (4) it may stimulate calcium ion efflux from mitochondria, and these actions may account for the inhibition by nicardipine of veratrine-induced contraction of myocytes. In this study, some of these effects of nicardipine were examined. However, the suggestion that nicardipine concentrates in ischemic cells owing to the tertiary amine structure could not be conclusively demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cellular action of nicardipine. 280 73

The angiotensin converting enzyme (ACE) inhibitor captopril proved to be an effective antihypertensive drug during a 5-year follow-up study of patients with severe hypertension who had been resistant to a triple-drug regimen. Of the 42 patients, 41 had to be treated additionally with diuretics. Because of hypokalemia, potassium supplements were necessary in 26 patients, despite the use of "potassium-saving" diuretics in 12 patients. Blood pressure was controlled sufficiently in 3/4 of the patients during the 5 years. Patients with a large elevation in plasma renin activity showed the best response to the treatment. Six patients died during the 5 years. Therapy had to be stopped in 11 patients because of complications. The following complications and adverse effects were observed: cerebral ischemia (n = 10), vertigo and orthostasis (10), exanthema (9), hypogeusia (7), circulatory failure (7), myocardial infarction (6), and scintigraphically demonstrable decrease of renal perfusion (5). One patient with bilateral renal artery stenosis suffered from acute renal failure, which was reversible after withdrawal of captopril. Significant changes of red and white blood cell counts, transaminases, lipids, urine protein excretion, and heart rate were not observed.
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PMID:[Results of a 5-year study with captopril in patients with severe therapy-resistant hypertension]. 302 Mar 11

The long-term use of oral anticoagulants like warfarin in artery disease has long been controversial. Possible aims of treatment include the primary or secondary prevention of systemic embolism, preventing recurrence after myocardial infarction or the progression of transient cerebral ischemia to a complete stroke, and the prevention of artery graft occlusion. The value of long-term anticoagulation is generally accepted in the few situations where, as in patients with mechanical heart valve prostheses, mitral valve disease and atrial fibrillation, or idiopathic dilated cardiomyopathy, the risk of arterial thromboembolism without anticoagulation is known to be high and there is good evidence that anticoagulants are effective, so the benefit:risk balance strongly favours their use. In many settings, however, it is hard to justify long-term warfarin treatment as the benefit:risk balance remains unknown; either because the risk of thromboembolism without anticoagulation remains to be clearly defined (as in the case of patients with 'lone' atrial fibrillation), or because possible benefits have not been well documented (as after transient cerebral ischemia or peripheral vascular surgery). Finally, there is the difficult problem of estimating the benefit from long-term anticoagulation after myocardial infarction. It seems that warfarin can reduce the likelihood of non-fatal reinfarction with relative safety in highly selected patients, but whether it reduces mortality, and how its effect compares with that of other, more recent, therapies aimed at preventing reinfarction, remains unknown.
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PMID:Long term warfarin treatment in artery disease. 304 62

In a prospective study of 87 patients with TIA or minor stroke (48 men and 39 women, average age 65 years) a history of ischaemic heart disease (IHD) was present in 30 (angina in 25 and myocardial infarction (MI) in 19, 14 having both). The London School of Hygiene Questionnaire did not confirm the diagnosis of IHD in 7 patients, but did detect a further 5 patients with angina and/or MI. The Minnesota coding of the ECG revealed 5 patients with asymptomatic suspect IHD and 15 with probable IHD (a total of 23%). Cardiomegaly (cardiothoracic ratio greater than 0.5) was present in 28 patients, 9 with a history of MI and 8 with a history of angina. These findings indicate that IHD is common in patients with cerebral vascular disease. As both probable IHD on Minnesota coding of the ECG and the presence of cardiomegaly are highly predictive of a poorer outcome, the findings add further weight to the argument that, amongst patients with minor cerebral ischaemia, a sub-group at high risk of death due to IHD can be detected by using simple methods rather than by performing routine coronary angiography on all patients as has been suggested in recent times.
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PMID:Unreported symptomatic and asymptomatic ischaemic heart disease in patients presenting with TIA or minor stroke detected by the London School of Hygiene Cardiovascular Questionnaire and Minnesota coding of a routine ECG. 326 47

Sixty consecutive patients with an asymptomatic mid-cervical murmur on auscultation were identified amongst 1000 patients who underwent duplex scanning of the extracranial carotid arteries during 1981-83. They were classified according to the scan results into 12 high risk subjects with greater than 75 per cent stenosis of an internal carotid artery, 37 low risk subjects with a less than 75 per cent stenosis and 6 with no detectable stenosis. The mean duration of follow-up was 3 years (minimum 2 years) or until stroke or death. One was lost to follow-up and four were excluded having undergone carotid endarterectomy during the study. Six of twelve subjects with greater than 75 per cent stenosis suffered a stroke (five fatal and one non-fatal). There were no premonitory signs except in one patient with non-focal cerebral ischaemia for 2 months before an hemispheric stroke. There was one fatal stroke in the less than 75 per cent stenosis group and none in the control group. In all, 17 (28 per cent) patients died (myocardial infarction, 8; stroke, 6; malignant disease, 3). These results confirm that asymptomatic carotid murmurs are associated with increased mortality with most having non-severe carotid disease on duplex scanning and few strokes during follow-up. There is an important minority with tight carotid stenosis who carry a worrying risk of stroke if left untreated.
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PMID:Asymptomatic carotid murmur: ultrasonic factors influencing outcome. 330 Aug 39

Aspirin inhibits platelet function by acetylating platelet cyclo-oxygenase. When aspirin is administered in doses as low as 40-160 mg per day, it inhibits platelet cyclo-oxygenase activity by more than 80%. The effect of aspirin on platelet function is maintained for the life-span of the platelet and there is evidence that aspirin also acetylates platelets before they are released in the circulation and while they are still within megakaryocytes. Aspirin also inhibits the synthesis of PGI2 by vascular wall cells but compared to the platelet, this vessel wall effect is relatively short-lived and requires slightly larger doses of aspirin. In vivo studies in rabbits indicate that very high doses of aspirin are thrombogenic. However, there is no evidence that aspirin is thrombogenic in man even when administered in high therapeutic doses. The optimal antithrombotic dose of aspirin has not yet been determined. Clinically, impressive results have been obtained with low doses of aspirin (ranging from 100 to 300 mg per day) in preventing aorta coronary bypass thrombosis, in patients undergoing hemodialysis, and in patients with unstable angina. Aspirin is also effective in preventing stroke and death in patients with cerebral ischemia when administered in doses of approximately 1 gram per day. There are trends suggesting that aspirin is effective when administered in doses between 300 mg per day and 1500 mg per day in patients who have survived myocardial infarction. The side-effects of aspirin are mainly gastrointestinal and are dose-related. Generalized bleeding is very uncommon and limited mainly to patients with other hemostatic abnormalities or due to the concomitant use of anticoagulant therapy.
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PMID:Effect of aspirin on hemostasis and thrombosis. 330 53

A retrospective review of 40 consecutive patients undergoing combined coronary artery bypass grafting (CABG) and unilateral carotid endarterectomy (CEA) was carried out to determine the stroke rate for the procedure. Patients presenting with severe coronary artery disease judged to be at risk of imminent myocardial infarction, who had signs of cerebral ischaemia (70%) or asymptomatic carotid bruits (30%), were investigated for extracranial carotid vascular disease. Patients with severe stenotic carotid lesions associated with high risk coronary artery disease underwent combined CEA/CABG. Three patients had a previous contralateral CEA. The average age of the patients was 62 years, and there were 31 males and nine females. CEA was completed prior to CABG under the same general anaesthetic. There were 24 CEAs on the left and 16 on the right. Six patients suffered a postoperative cerebral ischaemic event (15.4%): a reversible ischaemic neurological deficit in three (7.7%), a transient ischaemic cerebral event in two (5.1%), and a permanent stroke occurred in one (2.6%). Two deaths occurred and both were cardiac related. Combined CEA/CABG in patients with stenotic lesions of the coronary and extra-cranial carotid vascular systems who are at risk of cerebral or myocardial infarction, can be performed with a permanent stroke rate within the published range for either CEA or CABG alone and with a mortality of 5%.
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PMID:Combined carotid and coronary surgery. 331 91


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