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

Adequate vascular access is the hallmark of successful chronic hemodialysis for end-stage renal disease. Between May 1975 and August 1975, it was necessary to use a bovine xenograft in 91 instances to create an arteriovenous fistula for vascular access in patients receiving chronic hemodialysis at the Vanderbilt University Affiliated Hospitals. Forty-two patients had one xenograft, 14 patients had two, and seven had three xenografts. Of all fistulas created with the xenografts, 53% were patent six months after the operation, 36% were patent at 12 months, and 15% have remained patent for 24 months. Thirty-seven percent of the xenografts failed during the first three months after operation. The most common reason for failure was thrombosis of the xenograft. Other complications encountered were false aneurysms, infection of the graft, ischemia of the extremity, and bleeding. Amputation of the lower extremity due to ischemia from septic emboli was necessary in one case. There was no deaths directly related to the use of these xenografts. It is out current opinion that the bovine xenograft should be reserved for use in patients who have had failure of the more conventional type of internal fistula (Cimino type). In selected patients in whom it is not possible to create a Cimino shunt, the xenograft offers adequate primary vascular access.
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PMID:Vascular access for chronic hemodialysis: use of bovine xenografts to create arteriovenous fistulas. 63 13

Unstable angina is a syndrome which comprises a spectrum of symptomatic manifestations of coronary artery disease which lies between stable angina pectoris and acute myocardial infarction. Patients fall into three groups: angina of recent onset (4 weeks), angina of changing pattern, and angina occurring at rest (longer than 15 minutes). The syndrome may presage acute myocardial infarction or sudden death, or may itself be the manifestation of a myocardial infarction. The pathophysiology may involve primary cardiac events or extracardiac precipitating factors, and does not appear to be the consequence of a particular anatomic pattern of coronary artery disease. Pain may occur as a result of regional reduction of coronary flow to pressure-dependent areas of myocardium during states of increased myocardial oxygen demand. Persisting ischemia leads to infarction via a series of events which may include myocardial edema formation, increased beta-sympathetic tone, and others which have been experimentally modified by interventions designed to limit infarct size. Although the incidence of acute myocardial infarction and death was high in early studies, in recent reports acute infarction occurs in under 15.5 per cent and death in under 2 per cent. Patients at high risk are those pain persists with bed rest, and those with preceding stable angina pectoris or myocardial infarction. Prognostic differences among Groups 1, 2, and 3 may exist but cannot be assessed from available studies. Studies of the management of unstable angina have generally been uncontrolled. Hospitalization, bed rest, and short- and long-acting nitrates are generally employed in Groups 2 and 3 patients and the marked reduction in myocardial infarction rates from early to recent studies tends to support these approaches. Anticoagulants are less used now than formerly. Propranolol can produce a significant reduction of myocardial oxygen consumption and may redirect coronary flow to ischemic areas. The drug has effectively controlled pain in several studies and is now widely used to manage unstable angina. Aortocoronary bypass surgery has been extensively employed but there is only one preliminary report of a controlled study available. The role of surgery is not yet defined. The optimal approach to therapy may eventually involve the use of medical therapy, including beta-blockade to stabilize patients, with delayed semielective coronary angiography and surgery in those who respond. Emergency angiography and surgery might then be reserved for the high-risk group of patients whose pain persists during optimal medical therapy.
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PMID:Unstable angina pectoris. 78 21

Stress ulcers are multiple, superficial erosions which occur mainly in the fundus and body of the stomach. They develop after shock, sepsis, and trauma and are ofter found in patients with peritonitis and other chronic medical illness. Stress ulcers should be differentiated from reactivation of chronic duodenal or gastric ulcers. Cushing's ulcer following head injury, or drug-induced gastritis. Digestive symptoms are usually absent, hemorrhage is the most common manifestation, and perforation and obstruction are rare. The presence of luminal acid and ischemia are necessary for the production of stress ulcer, while disruption of the gastric mucosal barrier by refluxed duodenal content may contribute to the pathogenesis. Endoscopy is the mainstay of the diagnostic procedure, and angiography should be used if endoscopy fails to identify the bleeding lesions. Medical management should include volume replacement, nasogastric aspiration, and the use of antacid. Selective intraarterial infusion of pitressin has shown encouraging preliminary results. Surgical treatment is reserved only for those patients who continue to bleed despite all medical management. The operation of choice is open to question. We prefer vagotomy, pyloroplasty, and oversewing the ulcers as an initial operation. Since the result of all forms of therapy has been poor, it seems resonable to try to prevent ulcer development. The use of vitamin A, hyperalimentation, and growth hormones is still in an experimental stage. Large clinical studies with case control are necessary before recommendations can be made. The use of potent and frequent antacid to buffer the gastric content has shown promising results; however, these observations need to be confirmed in a properly controlled and randomized study.
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PMID:Stress ulcers: their pathogenesis, diagnosis, and treatment. 79 64

Considerable surgical progress of treating aortic dissection has been achieved during the past decade. The emergency indication for acute dissection of the ascending aorta (type A according to the Stanford classification) is unquestioned while surgical treatment for acute dissection of the descending aorta (type B dissection) is mainly reserved for complicated cases. The major complication of acute operations--fatal hemorrhage from the suture line and secondary multi-organ failure--have been successfully reduced by a progress of cardiopulmonary bypass techniques, the introduction of cold cardioplegic myocardial protection, the development of modern suture materials and glues and last not least by a continuous intensive monitoring. Especially the introduction of the so-called french glue safely enabled both the closure of the false lumen as well as the strong reinforcement of the diseased aortic wall and seems to offer a reliable alternative to the application of multi-layered teflon strips. Since the principle of all reconstructive approaches in case of dissection consists of closure of dissected layers and the limited replacement of the segment that is susceptible to a rupture the exact readaptation and reinforcement of the diseased aortic wall represents a fundamental operative step. In type A operations the supracoronary aortic prosthetic replacement or the combined replacement of ascending aorta plus aortic valve followed by the reattachment of coronary arteries has become the standard operative technique. In fact, independently from the location of the primary intimal tear the operation has been traditionally limited to replace the ascending aorta in order to remove an aortic segment that is most likely to rupture. Yet an increasing number of follow-up investigations has demonstrated recurrence of dissection or an aneurysmatical dilatation of the false lumen in about 20% of patients treated with ascending aortic replacement. Consequently, repair of the aortic transverse arch and the radical elimination of the intimal entry is now favoured by an increasing number of surgeons. In addition to these various perioperative and intraoperative adjuncts the introduction of new imaging techniques, especially computerized tomography, magnetic resonance imaging and transesophageal echocardiography allowed to establish adequate therapeutical concepts on a more rational basis. Transesophageal echocardiography as a mobile diagnostic device enables investigators to perform a bed-side dynamic visualization of both the location and extent of a dissection, the evaluation of ventricular performance and aortic competence. Treatment of acute type B dissection is mainly conservative unless complications like intractable pain, aneurysmatic enlargement of the false lumen, ischemia of visceral organs or even rupture occur.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Surgical therapy of thoracic aortic dissection]. 148 25

A typical case history of spontaneous dissection of the internal carotid artery is presented. In young patients with cerebral ischemia, initial pain in the affected side of the head and neck, a possible provocative mechanism and a transient or even persistent Horner's syndrome are highly suggestive. The angiographic picture of carotid artery dissection is characteristic. Spontaneous resolution is common, and recurrence rare. Surgical treatment can therefore be reserved for individual cases with recurrent ischemia and caused by emboli originating in the dissected segment of the artery.
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PMID:[Spontaneous dissection of the internal carotid artery]. 152 41

The preoperative assessment of the high risk patient undergoing noncardiac surgery has traditionally been based on history, physical examination, and preoperative testing. We propose a method of assessing preoperative risk based on the presentation of coronary artery disease, exercise tolerance, and extent of the surgical procedure. Since this is an evolving field, as new information and perioperative management techniques become available, the preoperative evaluation of the high risk patient will change. We have presented one approach based on our interpretation of data from the current anesthesiology and cardiology literature. In the patient with a recent MI, the predischarge symptom-limited stress test and the electrocardiographic classification can be used to better stratify risk. In the patient with angina, testing should be reserved for those patients who are candidates for coronary revascularization or alternative surgical procedures. In the patient at risk of but without overt symptoms of coronary artery disease, the number of clinical risk factors can determine the probability of coronary artery disease in the individual patient. The decision to perform preoperative revascularization should be based on its anticipated improvement of both the short- and long-term prognosis of the patient considering the risk of such procedures. The objective assessment of LVEF should be performed in patients with a poor exercise tolerance with either a high risk of perioperative ischemia or a suspicion of cardiomyopathy.
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PMID:Preoperative cardiac evaluation for noncardiac surgery: a functional approach. 155 27

Raynaud's phenomenon is mainly linked with cold provoked vasomotor perturbations, but also with rheological alterations since blood viscosity is enhanced by lowering temperature. Several methods are available for studying distal vascularization: peri-ungual capillaroscopy, digital plethysmography and laser-Doppler. Digital arteriography must be reserved to serious ischemia regarding the general anesthesia needed to avoid spasm. All these methods explore especially the vessel wall. Conservely, blood viscosity which has been developed for 25 years investigates the content of the vessel. Since 1965, numerous hemorheological studies pointed out the rheological disorders, especially those concerning plasma and blood viscosity. The most usual viscometry abnormalities revealed erythrocyte hyperaggregation, red cell hypodeformability, blood and plasmatic hyperviscosity. In a comparative study, 46 patients with Raynaud's phenomenon were studied: we performed peri-ungual capillaroscopy, plethysmography and viscosity measurements. The results demonstrated a link between capillaroscopy and thixotropy. Both investigations are never normal at the same time in connectivites and never abnormal at the same time in Raynaud's disease (primary Raynaud's phenomenon). In conclusion hemorheological studies showed nearly normal rheological parameters in Raynaud's disease, but abnormal rheological parameters in secondary Raynaud's phenomenon.
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PMID:[Raynaud's phenomenon and blood viscosity]. 160 50

Peripheral arterial disease requires different diagnostic strategies according to the clinical presentation: tissue ischemia, asymptomatic disease or polyarterial disease. In the presence of resting or effort ischemia, complementary investigations are indicated: arteriography should be reserved for indications of arterial reconstruction: ankle systolic pressure may be measured by all physicians to quantify the distal repercussions of the lesions. Asymptomatic peripheral disease is becoming more widely recognised and may be detected with flowmeter tests. Polyarterial disease is associated with increased mortality of patients with peripheral arterial disease. Symptoms of coronary artery disease are an indication for coronary angiography and myocardial scintigraphy. Patients with cerebrovascular events will require ultrasonic, CT scanning and cardiac investigations. The diversity of the diagnostic approach to peripheral arterial disease is creating a need for a new profile of vascular physicians.
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PMID:[Diagnostic strategy of vascular diseases of the lower limbs]. 176 85

In the context of peripheral vascular disease, the clinical history provides a means of evaluating coronary risk. The key features are: age, previous myocardial infarction especially when recent (under 6 months), anginal pain, smoking, diabetes and ventricular arrhythmias. Treadmill testing, often limited by symptoms of claudication, may reveal severe coronary ischemia and thereby the patients at very high risk. Upper limb exercise stress testing gives results similar to standard protocols of non-atherosclerotic patients when correctly performed and a reliable detection and evaluation of coronary lesions. Thallium dipyridamol myocardial scintigraphy is a very useful diagnostic method but requires special radionuclide facilities. This technique demonstrates the site of ischemia. Coronary angiography should be reserved for special cases because the risks of the procedure are always greater in patients with peripheral vascular disease.
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PMID:[Which coronary investigation should be performed in patients with peripheral arterial diseases?]. 176 87

Two groups of rats were tested on a variety of motor and cognitive tasks after either 10 minutes of two-vessel occlusion forebrain ischemia (n = 8) or sham operative procedures (n = 6). Histological injury was absent in the sham-operated group. In the ischemic group, hippocampal injury was restricted to field CA1, while damage in the neocortex and caudoputamen was sparse. Motor tests performed on postoperative days 18 and 28 revealed no significant differences between the ischemic and sham-operated groups. Retention performance of a radial maze discrimination task was impaired, with a significant but transient increase in both working and reference memory errors. Passive avoidance acquisition and retention were not significantly affected, although conclusions concerning the utility of this task must be reserved because of variability in the behavior of the sham-operated rats. Morris maze spatial navigation (place learning) and open-field activity were insensitive to treatment group. These functional results are consistent with the observed histological injury and what is known about hippocampal injury and behavior, and they provide further guidance for the development of neurological assays appropriate for discriminating outcome from forebrain ischemia in rats.
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PMID:Forebrain ischemia induces selective behavioral impairments associated with hippocampal injury in rats. 186 51


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