Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0038454 (stroke)
147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thromboembolism is a complication which represents a major limiting factor in animals with long-term postoperative survival periods following total artificial heart replacement. Thrombi are formed on the artificial valves, the biomaterials and in stagnation areas within the artificial ventricles. In design planning the stagnation areas should be avoided as well as major turbulences. The filling volume should be maximally used for the stroke volume and the epicenter of the membrane should be underneath the valve areas. The ellipsoid heart eliminates stagnation areas and the stroke volume is 82% of the filling volume. The maximum cardiac output is 15.8 l/min. The ellipsoid heart was implanted in 20 female calves; the maximum length of survival was 213 hours. There was no compression of the inferior vena cava and the heart fitted well into the chest of the animals. The cardiac output, self-regulated in the sense of Starling's law, was adequate to perfuse the animals and to allow moderate exercise such as standing. The arterial pressure curves show normal physiological activity. The curves in both atria are unphysiological, owing to relative insufficiency of the valves. The limiting factors were pulmonary insufficiency and surgical complications. The ventricles showed no thrombus formation -- except in one case, in which faulty material was the predisposing cause. It was possible to develop an automatic driving system on the basis of these experiments. Regulation occurred by means of gas flow control in the driving tubes, whereby the form of the gas flow curve provides information on position of the membrane. As soon as the membrane has reached the end-diastolic position, systole is triggered off and lasts until the end-systolic position is reached. If the venous return is increased, the ventricles are filled more rapidly and the heart is driven at a higher rate. One part of the ellipsoid heart is used as ventricle for assisted circulation. The left ventricle is cannulated via the left appendage or the apex. The ventricle relieves the left heart to a large extent and the cardiac output is taken over by the pump placed in a paracorporeal position. The blood is directed back into the thoracic aorta.
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PMID:[Design and haemodynamic evaluation of the ellipsoid heart for total heart replacement]. 26 18

Nine patients (4 women and 5 men; mean age 31 [20-48] years) with severe posttraumatic adult respiratory distress syndrome (ARDS) were treated with continuous postural change (kinetic bed) and pressure-limited ventilation. Seven patients survived; only one patient died as a result of pulmonary insufficiency. As compliance was markedly reduced (less than 20 ml/cm H2O), low stroke volumes (up to 380 ml) and high respiratory rate (up to 45/min) were employed to keep airway peak pressure below 40 mmHg. Kinetic treatment lasted for a mean of 14 (2-28) days; artificial ventilation was maintained for 31 (9-49) days. Practical problems of the method are the intensive nursing care required for the kinetic bed and the risk of decubitus ulcers, as well as disconnection of infusion tubing. The results indicate that kinetic treatment with pressure-limited ventilation constitutes a low-risk and, in many cases, effective treatment of severe ARDS.
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PMID:[Acute posttraumatic lung failure. Its treatment through pressure-limited respiration and continuous postural change]. 187 28

Between 1975 and 1986, 100 consecutive patients with aneurysms of the descending thoracic (84 cases) or the thoracoabdominal aorta (16 cases) underwent surgical repair. Intraluminal graft inclusion procedure was employed in principle under routine circulatory support with partial cardiopulmonary bypass. In this study, overall surgical results were reviewed, and multiple factors discriminately contributing to early results were assessed using multivariate analysis (quantification theory type II) to determine if this therapeutic modality is pertinent. Fifty-five patients had non-dissecting, 42 had dissecting aneurysms and 3 had pseudoaneurysms. Seventeen patients were treated in the emergency setting. Perioperative or early deaths occurred in 14 patients. Mortality increased with advanced age (greater than 70 years) and with atherosclerotic aneurysms, especially when they involved the entire thoracic or thoracoabdominal aorta. Operative mortality during the last 5 years of the study was 9.3%: significantly lower than the figure in the first 5 years of 28% (p = 0.0198). The incidence of renal dysfunction (7.4%) or paraplegia (2.1%) was not related to aortic cross-clamp time, and both were markedly decreased to 3.8% and 0.0%, respectively, when the cases of thoracoabdominal aneurysms were excluded. There were 8 cases of exploration for postoperative hemorrhage and 6 cases of pulmonary insufficiency requiring more than 3 days of mechanical ventilation. Prolonged bypass time was a discriminative risk factor for these two complications. Cerebral vascular accidents developed in 5 patients, three of them terminated in death. In spite of partial bypass, the factors of advanced age, atherosclerosis, and cross-clamp on the aortic arch were defined responsible for brain stroke.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Surgical repair of descending aortic aneurysms--experience in 100 patients under partial cardiopulmonary bypass]. 189 63

A prospective study of 26 patients undergoing descending thoracic aorto-iliac/femoral (DTAI/F) bypass was conducted over a 13-year period with an average follow up of 53 months. Reasons for selecting the procedure were occluded aortic bifurcation grafts (9 patients), hostile abdomen (6), infected aortic graft (1), microaorta (10, and surgeons preference in 8 patients who had juxtarenal aortic occlusion. The operative mortality was 3.8% (1 patient). A late mortality of 36% was due to myocardial infarction (1), lung carcinoma (2), renal failure (4), stroke (1) and pulmonary insufficiency (1). Graft failure occurred in 4 patients at 23, 26, 54 and 109 months respectively. Primary cumulative patency was 86% statistically valid at 42 months. DTAI/F bypass is recommended in selected patients when conventional approaches to the aorta are considered unduly hazardous.
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PMID:Long term follow-up of descending thoracic aorto-iliac/femoral bypass. 221 94

Operations for certain congenital cardiac lesions can produce pulmonary regurgitation. Pulmonary regurgitation contributes to right ventricular dysfunction, which may cause early postoperative morbidity and mortality. To ameliorate the problems of pulmonary regurgitation during the early postoperative period, we evaluated a method for its acute control. Complete pulmonary valvectomy was performed utilizing inflow occlusion in eight sheep. A catheter with a 15 ml spherical balloon was positioned in the pulmonary arterial trunk; its inflation and deflation were regulated by an intra-aortic balloon pump unit. Blood flow from the pulmonary arterial trunk and forward and regurgitant fraction were determined from electromagnetic flow transducer recordings. The regurgitant fraction with uncontrolled pulmonary regurgitation was 38% +/- 3% (forward flow = 42 +/- 5 ml/beat and regurgitant flow = 16 +/- 2 ml/beat). Inflation of the balloon during diastole was timed to completely eliminate pulmonary regurgitation. This balloon control of pulmonary regurgitation increased pulmonary arterial diastolic pressure from 12 +/- 1 to 17 +/- 1 mm Hg (p less than 0.0001) and decreased pulmonary arterial systolic pressure from 31 +/- 3 to 27 +/- 1 mm Hg (p = 0.06). Pulmonary arterial pulse pressure decreased from 19 +/- 3 to 9 +/- 1 mm Hg (p less than 0.003). Elimination of pulmonary regurgitation decreased right ventricular stroke volume (25 +/- 3 versus 42 +/- 5 ml/beat, p less than 0.0002) and resulted in a 46% reduction in right ventricular stroke work (5.0 +/- 0.6 versus 9.4 +/- 1.0 gm-m/beat, p less than 0.001) with no change in net forward pulmonary artery flow. Thus, acute pulmonary regurgitation can be controlled and this control improves overall hemodynamic status and decreases right ventricular work.
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PMID:Acute control of pulmonary regurgitation with a balloon "valve". An experimental investigation. 403 77

In order to reduce postoperative pulmonary insufficiency (PI) a transannular monocusp patch was implanted in 14 patients with severe tetralogy of Fallot and hypoplastic pulmonary valve ring (group A). The results of left and right heart catheterization, obtained within one year of the correction, were compared to those of 9 patients, who received a simple transannular pericardial patch (group B). The mean maximal systolic pressure ratio between the right and left ventricle (A = 0.43 +/- 0.03; B = 0.49 +/- 0.04), the mean maximal systolic pressure gradient between the right ventricle and the pulmonary artery (A = 10.38 +/- 0.52 mmHg; B = 12.2 +/- 2.5 mmHg), and the degree of PI (A = 24.7 +/- 3.4%; B = 22.0 +/- 3.0% of total stroke volume) were not significantly different (p greater than 0.05) for the 2 groups. Although optimally implanted, the available monocusp patches cannot prevent or reduce postoperative pulmonary insufficiency in patients with severe tetralogy of Fallot. This experience suggests the need for a simple transannular pericardial patch if the pulmonary valve ring requires enlargement.
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PMID:Reconstruction of the right ventricular outflow tract in tetralogy of Fallot and pulmonary stenosis with a monocusp patch. 617 15

Correction of right ventricular outflow tract obstruction remains a challenge to cardiovascular surgeons. In order to relieve this obstruction and at the same time prevent or minimize pulmonary insufficiency, we inserted a cusp-bearing transannular patch (monocusp) in 14 patients. To test this objective, we restudied 13 of these patients 0.5 to 4 months postoperatively, including quantifying pulmonary insufficiency using an accurate videodensitometric method. In all patients a degree of pulmonary insufficiency ranging from 8% to 46% of total stroke volume (mean 22.7 +/- 10.6%) was measured, and in all but one a residual right ventricular outflow pressure gradient of 2 to 22 mm Hg (mean 10 +/- 7 mm Hg) was measured. There was an inverse relation between the degree of pulmonary insufficiency and both the pressure gradient (r = -0.89) and the ratio of the pulmonary valve ring diameter to monocusp depth (r = -0.67). An ideal reconstruction of the right ventricular outflow tract obstruction, without any postoperative pulmonary insufficiency and stenosis, was not achieved by the implantation of a monocusp in the described fashion. The postoperative results were acceptable in only a few patients. A reduction of pulmonary insufficiency seems to be associated with a small residual pressure gradient as well as a relatively small cusp size. Additional studies are necessary to further improve surgical correction of right ventricular outflow tract obstruction with reproducible and predictable results.
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PMID:Short-term hemodynamic results after right ventricular outflow tract reconstruction using a cusp-bearing transannular patch. 663 52

Forty-six patients with severe pulmonary insufficiency were prospectively studied to compare the effects of resuscitation with either crystalloid or colloid. By random number, 26 patients received RL and 20 patients received 5 per cent ALB to maintain hemodynamic stability. Groups were comparable with respect to the cause of pulmonary insufficiency, age and sex. For the duration of the study and at 48 hours, there was no statistically significant difference between groups with respect to the following: cardiac index, colloid osmotic pressure (COP), pulmonary capillary wedge pressure (PCWP), COP-PCWP gradient, right and left ventricular stroke work indices, and amount of constant positive airway pressure required for treatment. Both groups had a significant improvement in intrapulmonary shunt (Qs/Qt) after 24 hours of treatment. The Qs/Qt in the ALB group was significantly lower than the RL group at the termination of the study, but this did not affect outcome. The RL group required more fluid than the ALB group, but the difference was not statistically significant. No clinical advantage was found for either solution in this study.
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PMID:Crystalloid versus colloid in fluid resuscitation of patients with severe pulmonary insufficiency. 670 32

The exercise hemodynamic values in two groups of patients with repaired tetrad of Fallot (eight patients with some residual pulmonary insufficiency and seven patients without insufficiency) were compared with values in seven patients with trivial pulmonary stenosis who had not been operated on. The patients with tetrad of Fallot underwent surgery after age 8 years and all had a good hemodynamic repair (no shunts and a right ventricular systolic pressure at rest of less than 60 mm Hg). Exercise increased the right ventricular outflow tract gradient by the same magnitude in all three groups of patients. However, both surgically treated groups experienced impaired cardiac pump function on supine exercise (that is, a lower than anticipated cardiac index for the amount of oxygen consumed and a significant decrease in stroke index). Exercise also caused both groups with repair to have a decrease in stroke index and a concomitant increase in right ventricular end-diastolic and pulmonary wedge pressures; in contrast, the patients with pulmonary arterial stenosis had an increase in stroke index and a concomitant decrease in right ventricular end-diastolic and pulmonary wedge pressures. These findings indicate that an impaired cardiac response to supine exercise can occur in patients in whom intracardiac repair of tetrad of Fallot was performed after early childhood, even though they have had a good hemodynamic repair. In addition, the impaired cardiac response to supine exercise in these patients was probably due largely to an altered myocardial compliance rather than to either residual pulmonary stenosis or pulmonary insufficiency.
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PMID:Hemodynamic abnormalities in response to supine exercise in patients after operative correction of tetrad of Fallot after early childhood. 727 Apr 41

Several invasive or not invasive technics were used to evaluate right ventricular insufficiency associated to severe chronic pulmonary insufficiency. But none of them were very accurate and now the use of EBT appears as a real improvement. We performed a prospective study with 50 patients waiting for a lung transplantation and we compared the values of right ventricular function obtained by EBT to those obtained by nuclear medicine and catheterism. Accuracy of EBT for left ventricule evaluation has already been proved. Stroke volumes calculated by EBT in right and left ventricules are similar and this constitutes a good validation of the method for right ventricule evaluation. Correlations with hemodynamic measurements are poor and nuclear medicine technics underestimate the ejection fraction. So, EBT is recommended for right ventricular study before and after lung transplantation.
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PMID:[Evaluation of the right ventricular function for lung transplantation. Value of the electron beam scanner]. 786 58


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