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

Recent advances in computer and radiological technology have permitted a reassessment of intravenous (IV) angiography in the evaluation of extracranial and intracranial vessels. This report reviews our initial experience with IV digital subtraction angiography in the diagnosis and treatment of brain ischemia. Two hundred seventy-three IV digital subtraction angiograms (146 extracranial, 127 intracranial) were performed on a total of 178 patients with suspected cerebral ischemia (159 patients), brainstem/cerebellar ischemia (13 patients), or asymptomatic bruit (six patients). Extracranial studies clearly demonstrated ulceration, stenosis, and occlusion of the carotid arteries. Intracranial studies usually detected major artery occlusive disease and provided insight into the collateral flow patterns. Intravenous digital subtraction angiography allowed the accurate assessment of arteries after carotid endarterectomy and brain bypass surgery. Although conventional angiography was usually recommend in patients treated surgically, IV digital subtraction angiography obviated the need for conventional studies in the initial evaluation of many patients.
JAMA 1982 Jun 18
PMID:Intravenous digital subtraction angiography in brain ischemia. 704 14

Modified exercise testing within three weeks of an acute myocardial infarction has been shown to be both a safe and feasible means for identifying patients at greater risk for subsequent cardiac events. An abnormal ECG and symptomatic response to exercise correlates with a higher morbidity and mortality. An ST-segment depression as well as angina are associated with a higher risk of recurrent ischemia and death. Elevation of the ST segment as well as inappropriately high heart rates and early development of fatigue and dyspnea are seen in patients with compromised left ventricular function. Exercise-induced premature ventricular contractions raise the possibility of increased sudden death. Patients identified to be at increased risk can be considered for more intensive medical or surgical treatment to reduce their morbidity and mortality. Patients considered to be at low risk can be spared needless invasive studies and unwarranted restriction of their physical activity. Patients may also accrue psychological benefit from these stress-test procedures.
JAMA 1981 May 08
PMID:Exercise testing soon after uncomplicated myocardial infarction. Prognostic value and safety. 723 Mar 77

In 334 consecutive admissions for acute stroke, the blood pressure was elevated in 84% on the day of admission. The blood pressure decreased spontaneously an average of 20 mm Hg systolic and 10 mm Hg diastolic in the ten days following the acute event without specific antihypertensive therapy and was elevated in only one third of the cases on the tenth hospital day. The early elevation in blood pressure is likely a physiological response to brain ischemia, and blood pressure falls as recovery of brain function occurs.
JAMA 1981 Nov 13
PMID:Blood pressure after stroke. 728 8

Dopamine hydrochloride has been established as effective in the treatment of hypotension and shock in patients with adquate blood volume. The physiological response is dose related. Administration of more than 10 microgram/kg/min results in alpha-receptor stimulation and vasoconstriction, and peripheral extremity ischemia has been reported. Four patients treated with dopamine subsequently had the development of peripheral ischemia and gangrene, resulting in the need for multiple extremity amputations. These reactions represent a major complication of treatment.
JAMA 1980 Mar 21
PMID:Multiple extremity amputations in hypotensive patients treated with dopamine. 735 65

Acute proctitis is a nonspecific disease secondary to many specific causes. These include ulcerative colitis, Crohn's disease, enteric infections, venereal disease, antibiotics, ischemia, and radiation therapy. Clinicians should avoid making a diagnosis until appropriate tests such as sigmoidoscopy, rectal biopsy, and stool analysis have been done.
JAMA 1980 Jul 25
PMID:Evaluation of acute proctitis. 739 28

Three-hour oral glucose tolerance tests (GTTs) were performed for 58 men with secondary impotence (SI), 63 with normal sexual function (NL), and 69 with premature ejaculation (PRE). All were apparently nondiabetic. Diagnoses of diabetes and impaired glucose tolerance were based on serum glucose levels during GTT as recently defined by the National Diabetes Data Group. Covariance analysis corrected for weight and age differences. Mean glucose levels in patients with SI were significantly higher at one and two hours after glucose ingestion than in the other groups. Seven patients with SI (12.1%) were found to have diabetes. The three groups did not differ notably in frequency of impaired glucose tolerance. Inorganic serum phosphate levels were lower for the SI group. The high frequency of diabetes in subjects with SI who have no diabetic symptoms (12.1%) suggests that localized neuropathy or penile ischemia may produce impotence in otherwise asymptomatic patients.
JAMA 1980 Nov 28
PMID:Previously unrecognized diabetes mellitus in sexually impotent men. 743 71

Neuroimaging was revolutionized by the development of computed tomography (CT) and standard T1- and T2-weighted magnetic resonance imaging (MRI). Magnetic resonance imaging and CT can adequately distinguish hemorrhage from infarction and depict ischemic stroke 12 to 24 hours after onset. However, during the critical initial hours after the onset of ischemic stroke, these imaging technologies do not adequately demonstrate the location and extent of infarction. Diffusion-weighted MRI and perfusion imaging, as well as advances in magnetic resonance spectroscopy, will enhance our ability to evaluate ischemic stroke shortly after onset. Some of the uses of MRI techniques are as follows: (1) Diffusion-weighted imaging can depict the location and extent of the ischemic lesion as soon as a stroke patient is available for examination. (2) Perfusion imaging evaluates blood flow within the brain's microvasculature and can reveal regions of perfusion deficits corresponding to major vascular territories. (3) Magnetic resonance spectroscopy evaluates metabolic abnormalities associated with focal brain ischemia by specific biochemical measurements. These MRI techniques will rapidly provide important information to clinicians about ischemia, guiding diagnosis and helping in the development of acute stroke interventions to improve outcome.
JAMA 1995 Sep 20
PMID:New magnetic resonance techniques for acute ischemic stroke. 767 6

OBJECTIVE--Recent clinical, laboratory, and epidemiological evidence that passive smoking causes heart disease was reviewed, with particular emphasis on understanding the underlying physiological and biochemical mechanisms. DATA SOURCES--Publications in the peer-reviewed literature were located via MEDLINE, citation in other relevant articles, and appropriate reports by scientific agencies. Greatest emphasis was given to work published since 1990. CONCLUSIONS--Passive smoking reduces the blood's ability to deliver oxygen to the heart and compromises the myocardium's ability to use oxygen to create adenosine triphosphate. These effects are manifest as reduced exercise capability in people breathing secondhand smoke. Secondhand smoke increases platelet activity, accelerates atherosclerotic lesions, and increases tissue damage following ischemia or myocardial infarction. The effects of secondhand tobacco smoke on the cardiovascular system are not caused by a single component of the smoke, but rather are caused by the effects of many elements, including carbon monoxide, nicotine, polycyclic aromatic hydrocarbons, and other, not fully specified elements in the smoke. Nonsmokers exposed to secondhand smoke in everyday life exhibit an increased risk of both fatal and nonfatal cardiac events.
JAMA 1995 Apr 05
PMID:Passive smoking and heart disease. Mechanisms and risk. 789 90

Over the past 2 decades, nifedipine in the form of capsules has become widely popular in the treatment of hypertensive emergencies. Unlike other agents, such as sodium nitroprusside, nicardipine hydrochloride, diazoxide, and nitroglycerin--which require intravenous administration and monitoring of blood pressure--nifedipine can be given orally, and close monitoring is said not to be necessary. Although administration of nifedipine capsules has been reported to be expedient and safe, it has not been approved by the Food and Drug Administration for labeling for treatment of hypertensive emergencies or of any other form of hypertension because of lack of outcome data. A review of the literature revealed reports of serious adverse effects such as cerebrovascular ischemia, stroke, numerous instances of severe hypotension, acute myocardial infarction, conduction disturbances, fetal distress, and death. Sublingual absorption of nifedipine has been found to be poor; most of the drug is absorbed by the intestinal mucosa. Given the seriousness of the reported adverse events and the lack of any clinical documentation attesting to a benefit, the use of nifedipine capsules for hypertensive emergencies and pseudoemergencies should be abandoned.
JAMA
PMID:Should a moratorium be placed on sublingual nifedipine capsules given for hypertensive emergencies and pseudoemergencies? 905 6

When faced with a patient with acute chest pain, clinicians must distinguish myocardial infarction (MI) from all other causes of acute chest pain. If MI is suspected, current therapeutic practice includes deciding whether to administer thrombolysis or primary percutaneous transluminal coronary angioplasty and whether to admit patients to a coronary care unit. The former decision is based on electrocardiographic (ECG) changes, including ST-segment elevation or left bundle-branch block, the latter on the likelihood of the patient's having unstable high-risk ischemia or MI without ECG changes. Despite advances in investigative modalities, a focused history and physical examination followed by an ECG remain the key tools for the diagnosis of MI. The most powerful features that increase the probability of MI, and their associated likelihood ratios (LRs), are new ST-segment elevation (LR range, 5.7-53.9); new Q wave (LR range, 5.3-24.8); chest pain radiating to both the left and right arm simultaneously (LR, 7.1); presence of a third heart sound (LR, 3.2); and hypotension (LR, 3.1). The most powerful features that decrease the probability of MI are a normal ECG result (LR range, 0.1-0.3), pleuritic chest pain (LR, 0.2), chest pain reproduced by palpation (LR range, 0.2-0.4), sharp or stabbing chest pain (LR, 0.3), and positional chest pain (LR, 0.3). Computer-derived algorithms that depend on clinical examination and ECG findings might improve the classification of patients according to the probability that an MI is causing their chest pain.
JAMA 1998 Oct 14
PMID:The rational clinical examination. Is this patient having a myocardial infarction? 1005 39


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