Pulmonary embolism in surgical practice.
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Biomedical subjects
Publications and source records attributed to D Bergqvist.
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Endothelial cell seeding might be of value in reducing the thrombogenicity of small-diameter vascular grafts. We investigated the capacity of endothelial cell-seeded grafts to produce prostacyclin and compared this with that of the unseeded graft as well as the native artery. Twelve sheep were operated on with carotid interposition of externally supported knitted dacron grafts. On one side of the neck the graft was seeded with endothelial cells, enzymatically harvested from the left jugular vein. After 3 weeks, three out of 12 seeded grafts, and one out of 12 unseeded grafts were occluded (N.S.). After excision, the grafts were mounted and perfused ex vivo for five 15-min periods. During the last period, arachidonic acid (4 micrograms/ml) was added to the perfusate. The resected carotid artery was used as a control. Prostacyclin was determined as the stable degradation product 6-keto-PGF1 alpha using radio-immunoassay, and expressed as pg mm-2 luminal surface. The native artery had a significantly higher release of prostacyclin than the seeded graft, which in turn had a significantly higher release than the unseeded graft. Histological examination showed weakly positive staining for factor VIII-related antigen on the luminal surface of seeded grafts. Scanning electron microscopy showed endothelial cells with typical endothelial tufts and was evaluated blindly from 10 areas of each graft. The extent of endothelial cell coverage was evaluated and scored from 0 to 2.5. The median score for the unseeded grafts was 0.3 and for the seeded grafts 1.5 (p = 0.008). Prostacyclin production was higher in seeded than unseeded grafts, but did not influence patency in this model.
Immediately after balloon dilatation of the rabbit aorta the release of prostacyclin is diminished. In this study the morphological appearance and time course for recovery of prostacyclin production after balloon dilatation have been investigated. Healthy rabbit aortas were analysed 1 h (n = 12), 1 week (n = 13) and 1 month (n = 13) after angioplasty. The production of prostacyclin, from dilated and non-dilated aortic segments, was recorded in a perfusion system. Prostacyclin was measured as its stable degradation product 6-keto-PGF1 alpha. Scanning electron microscopy and light microscopy were used to analyse the type of cells present at the luminal surfaces of the segments. When endothelial cells were found their degree of coverage was also estimated. One hour after balloon dilatation there was a lower production of prostacyclin from the angioplasty segments than from controls. Also, the response to added arachidonic acid (AA) was lower in the angioplasty segments. No endothelial cells were present in the angioplasty segments. After 1 week there was no difference in the basic production of prostacyclin but there was still a lower response from angioplasty segments to the addition of AA. The inner surfaces of the angioplasty segments were covered by three to five layers of smooth muscle cells (SMC). After 1 month, there was no difference in either the basic production or after the addition of AA between control and angioplasty segments. The angioplasty segments were covered with a multilayer of SMC. The control segments had an almost complete cover of endothelial cells at every time interval after angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)
OBJECTIVE: to compare two different statistical methods in predicting the outcome of surgery for chronic leg ischaemia. MATERIAL: the present study from the Swedvasc registry is based on an inception cohort of 1635 patients with chronic leg ischaemia (intermittent claudication in 609 and critical ischaemia in 1026 patients), who have been followed until 1 year after surgery. Outcome was classified as improved vs. not improved, amputated or dead in claudication and as the intact leg vs. amputation or death in critical ischaemia. METHODS: logistic regression analysis was compared to the inductive expert system program, Assistant Professional, in the prediction of outcome. Seventy per cent of cases in the data base were used to create a risk factor model including 17 variables registered in Swedvasc. These variables included an assessment of patients overall health status, severity of disease, the surgeon's experience and surgical procedures. This model was then evaluated using the remaining 30% of the patients in the data base. RESULTS: a risk score indicating a probability of an adverse outcome exceeding 0.5 was, in patients with intermittent claudication, associated with a sensitivity of 38% using logistic regression and 26% using Assistant Professional. The percentages of correctly predicted adverse outcomes were 29 and 50%, respectively. In patients with critical ischaemia, the sensitivities with the two methods were 68 and 38% and the predictive values 42 and 57%, respectively. CONCLUSIONS: the risk scores created with the two methods gave low sensitivities. It is concluded that risk functions could not be used to predict an adverse outcome in patients operated on for chronic leg ischaemia with the data set used.
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In a prospective study all positive phlebographies within the well-defined population of the city of Malmö, Sweden, during 1987 were studied in order to determine the incidence of deep venous thrombosis (DVT). Epidemiological data were analysed for the detection of patient groups at increased risk of DVT. The incidence was found to be equal for both sexes, i.e. 1.6 per 1000 inhabitants a year. Risk factors were found to be in accordance with earlier studies. The median age for men was 66 years, compared to 72 years for women. At diagnosis of DVT, 19% of subjects had a known malignancy and within 1 year 5% (19 cases) developed a new malignancy. Of the men, 29% had postoperative or post-traumatic (fracture) DVT, compared to 46% of the women. Fewer patients with DVT than expected (39%) belonged to blood group 0 (31%) (P less than 0.005). Pulmonary embolism (PE) was clinically suspected in only 5% of cases, and diagnosis was verified scintigraphically in 2% of cases. None of these died of PE, but of 6 patients who were found to have PE at autopsy, four died about 4 weeks after the DVT was diagnosed.
This article reviews the problem of bleeding in connection with epidural/spinal anaesthesia, with special emphasis on the use of low molecular weight heparins for thromboprophylaxis. There are methodological difficulties to studying the problem in a scientifically correct way because of the rarity of the complication. However, from the data in the literature there are no indications of an increased risk in using the combination of low molecular weight heparin in prophylactic doses and epidural/spinal anaesthesia. So far, there is only a single case report, of spinal haematoma, although low molecular weight heparins have been used in combination with epidural/spinal anaesthesia in at least 1,000,000 patients. In controlled studies, at least 10,000 patients have been given the combination without complications.
We report a case of Takayasu's disease with severe renovascular hypertension in a girl from Eritrea. In the "burn-out" phase after the erythrocyte sedimentation rate had normalized, reconstructive vascular surgery was performed as further progression of the disease seemed unlikely. However, probably due to her growth, the graft rotated and a second operation was successfully performed.
Two studies evaluating the effect of Orgaran prophylaxis on the incidence of postoperative thrombosis in hip fracture surgery are reported. In one Scandinavian study, dextran was used in the comparative group, and in the US study, warfarin was used. In both, Orgaran was significantly more effective in reducing the frequency of deep vein thrombosis without producing an increase in bleeding complications or other side effects.
Atherosclerosis is complicated by thrombosis and it has been suggested that a decreased prostacyclin and/or an increased thromboxane release from the vascular wall could play a part in this process. There are few reports dealing with determinations of prostanoid release from physiologically perfused normal and atherosclerotic vessel walls or from perfused atherosclerotic hearts. Therefore, fourteen rabbits were given 2% cholesterol added to the diet for 26 weeks, which led to atherosclerosis, verified by scanning electron microscopy. Five animals died, and in the surviving nine, as well as from ten healthy rabbits, the aorta was excised. The vessels were perfused with pulsatile flow at physiologic pressure five times for fifteen minutes with the addition of arachidonic acid to the last perfusate. Prostacyclin and thromboxane were determined as their stable degradation products 6-keto-PGF1 alpha and TxB2 by radio-immuno assay. Atherosclerotic and normal animals had the same initial release of prostacyclin but in the atherosclerotic animals the release did not decline with time as it did in the normal animals. The response to arachidonic acid was also higher in the atherosclerotic group. The release of thromboxane was not altered in the atherosclerotic group compared to the control group. It is concluded that prostacyclin release from aortas is altered in rabbits with diet-induced atherosclerosis compared to normal rabbit aortas, but that vascular thromboxane production is not.
OBJECTIVE: To analyse the prevalence of abdominal aortic aneurysms in the city of Malmö. DESIGN: Retrospective demographic study. SETTING: Malmö General Hospital. MATERIAL: Reports of all 45,838 necropsies done at the Department of Pathology, Malmö General Hospital 1958-1986. RESULTS: Abdominal aortic aneurysms were found in 4,300/100,000 men and 2,100/100,000 women. The mean annual age-standardised increase of aortic aneurysmal disease was 4.7% among men and 3.0% among women. The prevalence among men increased rapidly after the age of 55 and reached a peak of 5.9% at the age of 80; that among women increased after the age of 70 and reached a peak of 4.5% above the age of 90 years. CONCLUSION: The prevalence of aortic aneurysmal diseases has increased during the last three decades, and is age and sex-dependent.
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The early thrombogenicity of dacron vascular grafts with and without impregnation with collagen (n = 7) or gelatin (n = 7) was evaluated in a sheep carotid artery interposition model. Autologous platelets were labelled with 32P and reinjected. Flow was reduced to 25 ml/min to mimic a situation with poor run-off and the graft thrombogenicity was studied for 4 hours. The results showed no difference as regards patency, thrombus-free surface, or uptake of 32P-labelled platelets between collagen- or gelatin-impregnated grafts and their parent dacron grafts. Thus, no difference in early graft thrombogenicity could be documented.
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