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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The blood flow within the walls of the digestive tract must be sufficient to maintain its structural and functional integrity. All episodes of vascular insufficiency cause ischemic damage to the organ and carry the threat of diffuse or focal necrosis. Certain forms of ischemic colitis or proctitis arise from episodes of reduced peripheric or splanchnic blood flow; indeed, those that do not culminate in necorsis of the colonic wall are more frequently caused by hemodynamic disorders than by vascular occlusions. The crisis is often mitigated by the development of collateral circulation, which is nevertheless of rather meager quality, such that the patients are very vulnerable to subsequent slight changes in cardiac output. Necrotic, gangrenous ischemic colitis arises from a combination of occlusive damage to the arteries and general hemodynamic disturbances. The vascular insufficiency might be slight or severe, temporary or long-lasting, localized or diffuse. In addition, the attack occurs in a septic medium in the presence of an abundant microbial flora that may be highly pathogenic. Thus infection complicates and aggravates the ischemic damage, with the result that the gangrenous aspect of the lesions tends to hide their ischemic origin. Indeed, the variability of the manifestations of the disease represents one of its primary characteristics and is a function of the different causative factors. A knowledge of the anatomy and pathophysiology of the splanchnic circulation and its hemodynamics is essential for a full appreciation of the diagnosis and treatment of the disorders and for the adoption of the aggressive approach necessary to improve the poor prognosis of ischemic diseases of the colon and rectum. The salient points have been stressed in the present chapter. The features of the different forms of the disease have been described, together with the necessary medical treatment and the indications for surgical for surgical intervention. In the relatively rare cases where operation is necessary, the tactics and techniques have been described. All treatment should be based on (a) constant, prolonged intensive care; (b) precise monitoring of any change in status; and (c) rapid excision of any necrotic (often gangrenous) tissue. Ischemic colitis is most likely to occur in elderly patients with a history of cardiovascular disease, but it is not excluded in younger individuals. It is a frequent entity and is potentially lethal. Although its clinical, radiological, and anatomical characteristics permit its classification as a separate disease, it is often confused with other disorders of the colon. Although the abdominal surgeon is most likely to be concerned with this disease, the vascular surgeon who attacks the lower aorta should always be on the lookout for possible occurrences of segmentary ischemia of the distal colon as a result of his intervention.
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PMID:Ischemic diseases of the large intestine. 38 38

Eighteen patients with idiopathic optic neuropathy lacked symptoms and signs of cardiovascular and cerebrovascular disease, especially when compared to three groups of patients with sudden visual loss caused by retinal infarction, transient ischemia, and cerebral infarction. Many patients in the latter groups had hypertension, carotid bruits, heart disease, transient ischemic attack, and stroke. But among the patients with ischemic optic neuropathy, hypertension was the only evidence of cardiovascular disease, affecting 44% of the patients. We argue that, in many cases, ischemic optic neuropathy represents a direct and early complication of hypertension arterial disease affecting small arterioles supplying the anterior part of the optic nerve. The pathologic process may thus be similar or identical to lacunar infarction of the brain.
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PMID:Ischemic optic neuropathy as a possible early complication of vascular hypertension. 51 8

The diagnosis of occlusion of the intradural vertebrobasilar artery (OIDVBA) was made by means of cerebral angiography in 22 patients. The clinical presentation, course and followup were studied in conjunction with the angiographic findings in each case and the following conclusions made. OIDVBA is not rare. It occurs one-fourth as often as occlusion of the carotid artery. The correct diagnosis is not made clinically before angiography in the majority of patients. Complete visualization of the neck and intracranial vasculature is necessary to document the occlusion. Atherosclerotic thrombosis is the most common type of occlusive lesion. The most common predisposing factors are atherosclerosis, hypertensive cardiovascular disease, diabetes mellitus, and developmental vertebrobasilar hypoplasia. Most patients with occlusion are in the 7th and 8th decades of life and transient attacks of vertebrobasilar ischemia precede the occlusion in one-half of the cases. Emboli usually lodge in the terminal portion of the basilar artery whereas thrombotic occlusions tend not to be located in a characteristic segment. A majority of patients diagnosed angiographically survive their OIDVBA, but most distal occlusions result in death, often following several weeks of coma. In the surviving majority, disturbance of gait, impairment of vision, and symptoms of transient vertebrobasilar ischemia are the most common sequelae.
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PMID:Occlusion of the intradural vertebrobasilar artery. 63 67

Sudden death, known since antiquity, is almost always due to cardiovascular disorder, but not exclusively to coronary artery disease. It is postulated that two processes, action of pre-existing risk factors (enlarged heart, abnormal conduction, extra systoles, ischemia) and new, untoward events (acute infarction or ischemia) culminate in the catastrophic event. Sudden death is apparently most likely during waking hours; sleep is a lesser risk. Which subjects are at greatest risk and which circumstances are most dangerous remain unknown and are important topics for further investigation.
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PMID:Time, place, event of sudden death. 110 45

The prognosis of left bundle branch block is determined by associated cardiovascular disease. Exercise electrocardiography is not helpful in detecting ischemia in these patients. Exercise thallium-201 scintigraphy has been widely accepted for that purpose. The authors made an overview of several studies suggesting that exercise thallium-201 scintigraphy has low specificity regarding left anterior descending coronary artery disease. They also review the mechanisms of perfusion defects in patients with left bundle branch block without coronary artery disease. One important question to be clarified is weather small defects are unrelated to coronary artery disease. Finally the authors analyse a few methods to increase diagnostic accuracy of perfusion scintigraphy in left bundle branch block. First the employment of a new criterium that requires the apex to be abnormal to indicate left anterior descendent artery disease. Second Pharmacological Stress with Dipyridamole or Adenosine. Third imaging with Tc-99m-MIBI.
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PMID:[What is the value of myocardial perfusion studies with isotopes in patients with complete left bundle branch block?]. 129 Jun 46

We describe a patient with acute intestinal ischemia successfully treated with embolectomy of the superior mesenteric artery. Over the last four years, 11 patients with the same disease were treated with bowel resection at Nordland Regional Hospital. The mortality rate after bowel resection was 45%. Long duration of symptoms, and high frequency of associated cardiovascular disease was characteristic. In elderly patients with acute abdominal pain and cardiovascular disease, a diagnosis of acute mesenterial ischemia should be seriously considered. In patients with acute mesenteric ischemia and no bowel necrosis, embolectomy must be considered in preference to bowel resection.
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PMID:[Surgical treatment of acute intestinal ischemia. Successful treatment with embolectomy of the superior mesenteric artery]. 141 88

The purpose of the present study was to determine whether 15 weeks of dietary fish oil supplementation to Wistar Kyoto (WKY) and stroke-prone spontaneously hypertensive rats (SP-SHR) would alter cardiac contractile performance. Isolated perfused working hearts were used to determine the effects of varying left atrial filling pressures on cardiac pump output and pressure development. In addition, the ability of these hearts to recover cardiac output after a 60-minute period of low-flow ischemia followed by 30 minutes of reperfusion was assessed. Myocardial high-energy phosphate levels and long-chain acylcarnitine content were measured. Fish oil supplementation had no effect on indirect tail-cuff systolic blood pressure of WKY rats, but produced a small decrease in systolic blood pressure of SP-SHR. In response to varying left atrial filling pressures, hearts from WKY rats and SP-SHR exhibited no major differences in aortic flow, left intraventricular diastolic pressure, systolic pressure, positive and negative rate of pressure change per unit of time (dP/dt), or relaxation time; however, coronary flow values were lower in SP-SHR groups relative to respective WKY groups. Fish oil supplementation had no effect on these cardiac parameters. When these hearts were subjected to ischemia and reperfusion, the recovery of cardiac contractile performance was significantly improved in fish oil-fed WKY and SP-SHR groups, compared with their corn oil-fed counterparts. There were no differences in the recovery of the above cardiac hemodynamic parameters between corn oil-fed WKY and SP-SHR. These results provide further support to the hypothesis that dietary fish oil can significantly reduce the mortality risk from cardiovascular disease.
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PMID:Effects of dietary fish oil on myocardial ischemic/reperfusion injury of Wistar Kyoto and stroke-prone spontaneously hypertensive rats. 158 34

We have used continuous and concurrent monitoring of arterial oxygen saturation (SpO2) and ECG to study the relationship between hypoxaemia and silent myocardial ischaemia in the perioperative period in 11 patients with cardiovascular disease. Ischaemic and hypoxaemic events occurred in all patients. Many events were shortlived and occurred independently of each other. However, our results suggest a close correlation between the duration of hypoxaemia and myocardial ischaemia. Ischaemia is more likely to occur if an episode of hypoxaemia is prolonged (beyond 5 min; P less than 0.01, chi square) and severe (SpO2 less than 85%; P less than 0.05, chi square).
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PMID:Relationship between hypoxaemic and cardiac ischaemic events in the perioperative period. 164 34

The Cardiovascular Health Study (CHS) is a population-based, longitudinal study of coronary heart disease and stroke in adults aged 65 years and older. The main objective of the study is to identify factors related to the onset and course of coronary heart disease and stroke. CHS is designed to determine the importance of conventional cardiovascular disease (CVD) risk factors in older adults, and to identify new risk factors in this age group, especially those that may be protective and modifiable. The study design called for enrollment of 1250 men and women in each of four communities: Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Pittsburgh, Pennsylvania. Eligible participants were sampled from Medicare eligibility lists in each area. Extensive physical and laboratory evaluations were performed at baseline to identify the presence and severity of CVD risk factors such as hypertension, hypercholesterolemia and glucose intolerance; subclinical disease such as carotid artery atherosclerosis, left ventricular enlargement, and transient ischemia; and clinically overt CVD. These examinations in CHS permit evaluation of CVD risk factors in older adults, particularly in groups previously under-represented in epidemiologic studies, such as women and the very old. The first of two examination cycles began in June 1989. A second comprehensive examination will be repeated three years later. Periodic interim contacts are scheduled to ascertain and verify the incidence of CVD events, the frequency of recurrent events, and the sequellae of CVD.
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PMID:The Cardiovascular Health Study: design and rationale. 166 7

Cigarette smoking is a strong but avoidable risk factor for development of cardiovascular disease and its acute complications. Intermittent claudication is most strikingly associated with smoking. The link between smoking and occlusive peripheral arterial disease is dose-dependent and can be broken by cessation of smoking. The risk of chronic as well as acute limb ischemia is then decreased in conservatively treated patients and also in those with reconstructive arterial surgery. Heavy smoking seems to abolish the positive effect of adjuvant antiplatelet medication. Cessation of smoking is a cornerstone in the management of occlusive peripheral arterial disease at any stage.
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PMID:Smoking and occlusive peripheral arterial disease. Clinical review. 167 15


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