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Biomedical subjects

D Bergqvist

Publications and source records attributed to D Bergqvist.

At least 361 records · Page 20Linked to original sources

Thromboprophylactic effect of low molecular weight heparin started in the evening before elective general abdominal surgery: a comparison with low-dose heparin.

A prospective randomized double-blind trial was performed comparing conventional low-dose heparin with a LMWH fragment (Kabi 2165, Fragmin) for thromboprophylaxis in elective general abdominal surgical patients. The first dose of the fragment was given in the evening before surgery, and thereafter every evening. There were 1002 analyzable patients, 826 having received correct prophylaxis. Sixty three percent of the patients were operated on for malignant diseases. The frequency of DVT was significantly reduced among patients with correct prophylaxis with the heparin fragment (9.2 to 5.0%, p = 0.02). In patients with malignancies the reduction was from 11.2 to 6.4% (p = 0.06). The frequency of bleeding was 6.7% among the heparin fragment patients and 2.7% among the patients given conventional heparin (p = 0.01). The corresponding frequencies for patients with malignancies were 3.2 and 2.8%, respectively (p = 0.28). All bleedings were minor and of no clinical significance. Local pain at the injection site was reported significantly less often among patients with the fragment. Twenty patients died, 13 with malignant disease, mortality being the same in the two groups. It is concluded that heparin fragment administered in the evening before surgery and then every evening is a practically acceptable alternative to prevent postoperative DVT in patients undergoing elective abdominal surgery, also when the histology shows malignancy. Thus, the advantages of using LMWH compared with conventional low-dose heparin are simplified administration routines, better thromboprophylactic effect, and less local pain at injection sites. A disadvantage is the slight increase in hemorrhagic side effects, all of minor clinical importance and not seen in patients undergoing surgery for malignancy.

Abdomen↗

The effect of unfractionated and low-molecular-weight heparin on the release of prostacyclin from the arterial wall.

Heparin is widely used as an antithrombotic agent, but one reported complication is thrombocytopenia associated with platelet aggregation. The mechanism is not fully clear but heparin interference in the prostaglandin production has been proposed. To investigate if heparin interacts with the production of prostacyclin from the vessel wall, and if low-molecular-weight heparin differs from unfractionated heparin in this respect, excised rabbit aortas were studied in a perfusion model. The vessels were perfused ex vivo for 5 x 15 min and in the last period arachidonic acid was added. Unfragmented heparin (500 IU/kg body weight) or low-molecular-weight heparin (LMWH) (500 antifactor Xa units/kg body weight) were given either 15 min before harvesting the vessels or added directly to the perfusate. The stable degradation product for prostacyclin, 6-keto-PGF1 alpha was not altered by addition of these agents. It is concluded that heparin and LMWH per se do not interact with the prostacyclin system in normal rabbit aortas in the doses studied.

6-Ketoprostaglandin F1 alpha↗

The cost-effectiveness of prevention of post-operative thromboembolism.

In recent years, value for money in health care has become of increasing concern. There are various ways to perform an economic evaluation, the most simple being a cost-effectiveness analysis, where differences in costs will influence the choice between methods. Cost-utility and cost-benefit analyses represent more advanced forms of economic evaluations. In this cost-effectiveness analysis, the following three strategies aimed at solving the problem of post-operative thromboembolic complications were compared: (a) no prophylaxis but treatment of occurring complications, (b) general prophylaxis with low-dose heparin for patients over 40 years of age and (c) selective treatment based on post-operative surveillance with a fibrinogen uptake test. Moreover, these alternatives were evaluated for three types of surgery: general abdominal surgery, cholecystectomy and elective hip surgery. Costs for thromboembolic and haemorrhagic complications were estimated from data available for patients hospitalized in Malmö. A sensitivity analysis was made with regard to the frequency of thrombosis, prophylactic effect and treatment costs. Health care costs would be minimized with general prophylaxis in hip and general surgery, whereas no prophylaxis is the most cost-effective alternative in cholecystectomy patients, i.e. with a frequency of thrombosis below 8%. General prophylaxis minimized the duration of patients' health losses due to thromboembolic disease in general, as well as in elective hip surgery. After cholecystectomy, no difference in health loss for the individual was found between the alternative of no prophylaxis and general prophylaxis. Selective treatment was always the least satisfactory alternative in all categories and always the most expensive.

Cost-Benefit Analysis↗

Venous haemodynamics of the upper extremity after subclavian vein thrombosis.

Late post-thrombotic complaints after subclavian vein thrombosis are reported with highly varying frequencies (8-80% severe disability). The therapeutic approach depends partly on this frequency. With the aim to evaluate late sequelae a questionnaire was answered by 26 patients with arm-shoulder symptoms leading to arm phlebography, but where the examination did not reveal any thrombi. 65% had remaining symptoms 2-9 years after the examination. 3 had to change profession. 36 patients with phlebographically shown subclavian vein thrombosis answered the same questionnaire. Only 9 (25%) had remaining symptoms and in 4 it was classified as mild, in 4 as moderate and only in 1 patient as severe leading to change of profession. Venous haemodynamics in the upper extremity were also studied in 3 groups of patients; I) healthy volunteers (n = 16 arms), II) patients with arm-shoulder disabilities with negative arm phlebography (n = 7 disabled arms, n = 7 non-disabled arms), III) patients with phlebographically verified subclavian vein thrombi (n = 10 arms with DVT, n = 8 arms without DVT). Strain gauge plethysmography was used measuring venous capacity and maximal venous outflow. Venous pressure measurements were made both with the arms in a resting position and in a military position with and without work-load. Repeat phlebography of arms with symptoms were made. Maximal venous outflow was significantly lower in arms with previous subclavian vein thrombi (p less than 0.05) and venous pressure measurements with the arm in military position was significantly higher in those arms. However, no correlation between these measurements and the degree of arm disability was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Lower-limb oedema after thromboembolectomy for acute arterial occlusion.

To establish the degree of oedema after thromboembolectomy ad modum Fogarty, leg volume changes were recorded daily in 56 patients. Significant increase was found in the volume of the ipsilateral leg, maximally 12.9 +/- 12% after c. 1 week. The swelling was significantly greater if the popliteal artery had been explored than if it had not. The volume increase was weakly correlated to the duration of ischaemia, but this could be explained by higher incidence of below-knee incisions in patients with longer preoperative ischaemia. Compartment syndrome occurred in one case. The outcome of the operation correlated to leg volume changes on postoperative day 1, but not significantly to the maximal volume increase. It is suggested that the early volume changes represent increased microvascular permeability, and that to this relatively modest oedema is in some cases later added more severe swelling due to impairment of the lymphatic outflow.

Arterial Occlusive Diseases↗

Prostanoid release from ex vivo perfused canine arteries and veins: effects of prolonged perfusion, intermittent perfusion, as well as exposure to exogenous arachidonic acid, thrombin and bradykinin.

Regulation of prostanoid release from ex vivo perfused vessel segments is not fully understood. A series of perfusion experiments were performed with canine arteries and veins to define certain regulatory phenomena. Arteries were perfused with pulsatile flow of 90 ml/min at a pressure of 100 mmHg, and veins with nonpulsatile flow of 90 ml/min at a pressure of 7 mmHg. Segments were perfused with Hanks' balanced salt solution for five 15-min periods with the perfusate exchanged after each study period. With onset of perfusion, there was an initial burst of prostacyclin release to 127 +/- 40 pg/mm2, declining to 32 +/- 10 pg/mm2 after 60 minutes (p less than 0.005). If perfusion continued for 5.5 hours, there was a stable release period between 1 and 3 hours, followed by a very slow decline. At that time addition of arachidonic acid (AA) increased prostacyclin release six-fold (p less than 0.01). Vessels perfused for 1 hour and then rested for another hour, responded to reperfusion at the second onset of flow with a two-fold increase in prostacyclin release (p less than 0.01). Vessels perfused with thrombin, bradykinin or AA (either added to each perfusate or only to the last perfusate) exhibited greater prostacyclin release than did control segments. Release of thromboxane steadily declined with time in all parts of the study, and only increased with the addition of AA to the perfusate.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗

Thromboxane A2-receptor blockade and prostacyclin in porcine Escherichia coli shock.

Septic shock was induced by intravenous infusion of live Escherichia coli in pigs to investigate the influences on central hemodynamic, coagulation, and fibrinolytic reactions by a thromboxane A2 (TxA2)-receptor blocker (BM 13.177; n = 6) and a prostacyclin analogue (iloprost or ZK 36,374; n = 7). The early pulmonary vasoconstriction following E coli infusion was attenuated, but not abolished, by BM 13.177. Only minor effects were seen after pretreatment with iloprost. Neither drug had any major effect on the coagulation and fibrinolytic activation. These results confirm that TxA2 is an important, but not the only, mediator of early pulmonary vascular response in porcine septicemia and that neither TxA2 nor prostacyclin is of major importance for the hemostatic reactions in this shock model.

Animals↗

Ultrasonographic screening of the abdominal aorta among siblings of patients with abdominal aortic aneurysms.

To evaluate the prevalence of abdominal aortic dilatations among asymptomatic brothers and sisters of patients with abdominal aortic aneurysms (AAAs), an ultrasonographic screening study was performed. One hundred and two siblings of patients operated on for AAAs at two Swedish hospitals were invited to attend, and 87 of them (35 men and 52 women) from 32 different families, accepted the invitation. Their median age was 63 years (range 39-82 years). Aortic dilatation was diagnosed in ten of the brothers (29 per cent) and three of the sisters (6 per cent). In ten cases (eight men and two women) there was a localized dilatation caudal to the coeliac axis, and in three a general dilatation of the abdominal aorta with the diameter at the coeliac axis greater than 29 mm. None of the aortic dilatations had been known before this study was performed. The conclusion is that the prevalence of asymptomatic aortic dilatations among brothers of patients with AAAs seems to be high and that this group should be selected for further screening studies.

Adult↗