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D Bergqvist

Publications and source records attributed to D Bergqvist.

At least 127 records · Page 7Linked to original sources
PubMed1998

Are safety committees really safe?

In an increasing number of recent major clinical trials, independent safety committees or safety monitors have been involved. Their role and function is not yet defined and continues to evolve. The aim of this paper is to discuss the role and tasks of safety committees as a result of our collective experience as members of three safety committees of studies evaluating antithrombotic prophylaxis against postoperative deep vein thrombosis. We believe that the type of pharmacological intervention used is of less importance than the general experiences gained, which can be extrapolated to other studies and should stimulate a more general debate.

Clinical Trials as Topic↗
PubMed1998

Economic evaluation of desirudin vs heparin in deep vein thrombosis prevention after hip replacement surgery.

Deep vein thrombosis is a serious complication of orthopaedic surgery and can lead to pulmonary embolism and long term post-thrombotic syndrome. A simulation model based on both epidemiological data and data from clinical trials was used to compare the long term cost effectiveness of standard prophylaxis with subcutaneous unfractionated heparin with that of desirudin (recombinant hirudin), in patients undergoing elective hip replacement. The analysis, which was performed before the price of desirudin was set, showed that prophylactic treatment with desirudin saved 4.5 life-years per 100 patients treated, compared with unfractionated heparin. Desirudin prophylaxis was dominant up to a total drug cost of 4400 Swedish kronor (SEK) per treatment. The results were robust against changes in the parameters used in several sensitivity analyses. This study showed that prophylactic therapy with desirudin compared with unfractionated heparin was more cost effective and potentially cost saving under a wide range of assumptions concerning the future price of desirudin in preventing deep vein thrombosis following elective hip surgery.

Anticoagulants↗
PubMed1998

2D inflow MR angiography in severe chronic leg ischemia.

PURPOSE: The aim of this study was to compare 2D inflow MR angiography (MRA) with selective X-ray angiography (XRA) in patients with severe chronic leg ischemia. MATERIAL AND METHODS: In a blinded prospective study, 2D inflow MRA and XRA were compared with regard to evaluation of the arteries distal to the knee in 24 patients (median age 72 years) with severe ischemia; 23 of them had either rest pain or tissue loss. Statistics were calculated with XRA as the reference method. RESULTS: The interpretations of 2D inflow MRA and XRA showed moderate agreement in the calf arteries but poor agreement in the foot arteries. Of the discrepancies, two-thirds were observer-related and only one-third method-related. Of all the comparable arteries, 9% showed method-related differences between the two methods. An assessment of MRA using only maximum intensity projections (MIP) resulted in 19% of findings being judged inconclusive whereas all the arteries could be classified when the cross-sectional images were studied on the viewing console. CONCLUSION: The agreement between MRA and XRA was good in the calf but questionable in the foot.

Adult↗
PubMed1997

The effect of protamine sulphate on plasma tissue factor pathway inhibitor released by intravenous and subcutaneous unfractionated and low molecular weight heparin in man.

Heparin, a negatively charged sulphated glycosaminoglycan, is clinically the most important antithrombotic drug. Heparin augments the inhibitory activity of antithrombin (AT) towards thrombin, factor Xa (FXa) and other activated clotting enzymes. Tissue factor pathway inhibitor (TFPI) is an endogenous heparin releasable three domain Kunitz-type coagulation inhibitor which inhibits the crucial tissue factor-factor VIIa (TF-FVIIa) dependent coagulation pathway in the presence of FXa. The importance of the TF-FVIIa pathway and TFPI has recently been reviewed (1). TFPI is located to different vascular pools, the largest being the vascular endothelium from where TFPI can be released dose-dependently to the blood by heparins (2). TFPI is speculated to contribute to the anticoagulant properties of heparins, but to which degree is not yet fully understood. In recent years low molecular weight heparins (LMWH) have proven to be effective and safe both for prophylactic (3) and therapeutic treatment (4) of deep vein thrombosis (DVT). Protamine is the least toxic and clinically most commonly used antidote to heparin. However, in vitro and in vivo LMW heparinized blood is not fully neutralized by protamine, as substantial anti-Xa activity remains following neutralization (5). This post-protamine effect has been shown to be partly TFPI dependent when measured in a dilute TF-dependent assay (6,7). We undertook this in vivo study on healthy volunteers in order to investigate whether TFPI released by UH or LMWH (intravenous (iv) or subcutaneous (sc)) remains in the circulation following neutralization of the heparin activity with protamine sulphate (PS). We measured TFPI by three different methods-chromogenic activity, anticlotting activity and a new antigen assay specific for full-length and three-domain TFPI.

Age Factors↗
PubMed1997

Cost of long-term complications of deep venous thrombosis of the lower extremities: an analysis of a defined patient population in Sweden.

BACKGROUND: Little information is available on the epidemiology and economic effect of long-term complications developing after deep venous thrombosis. OBJECTIVE: To determine the extent of, timing of, and treatment costs associated with long-term complications developing after deep venous thrombosis of the lower extremities. DESIGN: 15-year retrospective cohort study. SETTING: County hospital in Sweden. PATIENTS: 257 patients with deep venous thrombosis and 241 age- and sex-matched controls without deep venous thrombosis. MEASUREMENTS: Data on use of health care resources and costs of inpatient and outpatient care, pharmaceutical agents, and treatment of complications. RESULTS: After 15 years of follow-up, 35% of the patients with thrombosis and 57% of the controls were alive. Two hundred forty-two complications were reported among the patients with thrombosis, and 25 similar events were reported among the controls. The average expected present value of the health care cost of treating complications of thrombosis was estimated to be about $4659 in the patients with thrombosis and $375 in the controls. In controls, primary deep venous thrombosis cost about $6000; thus, the additional long-term health care cost of post-thrombotic complications is about 75% of the cost of primary deep venous thrombosis. CONCLUSIONS: The economic effect of post-thrombotic complications is considerable. The use of measures to prevent thromboembolism and its long-term complications are justified on both clinical and economic grounds.

Follow-Up Studies↗
PubMed1997

Possible benefit of preoperative blood deposit for abdominal surgery.

Predictors for the need of blood transfusion were analyzed using multiple regression analysis in 1689 patients undergoing elective major abdominal surgery before the age of 80 years and with a preoperative blood hemoglobin concentration above 110 g/L. Rectal surgery for malignant disease and pancreatic surgery (for malignant or benign disease) were associated with higher transfusion requirements (mean 2.4 units) than other operations (0.6 units). If two autologous units had been available in-these patients, the fraction needing allogeneic transfusion could have been reduced from 59% to 31%. It would not be effective to predonate more than 2 units. For other types of surgery the rate of allogeneic transfusion would not have been much reduced, and most autologous blood would have been wasted.

Adult↗
PubMed1997

Hemodynamic changes in the inferior caval vein during pneumoperitoneum. An experimental study in pigs.

BACKGROUND: Laparoscopic procedures of increasing difficulty and duration are becoming more and more common. This may cause significant challenges to the circulatory system and possibly influence thrombogenicity. METHODS: Experimental study of carbon dioxide pneumoperitoneum in pigs. RESULTS: Inferior caval vein blood flow remained unchanged, whereas inferior caval vein pressure increased during pneumoperitoneum. Inferior caval vein, pulmonary, and systemic vascular resistance increased during pneumoperitoneum and remained increased after exsufflation. CONCLUSIONS: Pneumoperitoneum leads to an increased inferior caval vein pressure, which could cause a dilation of peripheral veins. The similar patterns of vascular resistance in the inferior caval vein, pulmonary artery, and systemic arteries (a gradual increase remaining elevated after exsufflation) suggest a common humoral factor or increased sympathetic nerve activity.

Animals↗
PubMed1997

Risk factors for intestinal ischaemia after aortoiliac surgery: a combined cohort and case-control study of 2824 operations.

OBJECTIVE: To identify risk factors for intestinal ischaemia after aortoiliac surgery. MATERIALS AND METHODS: Among 2824 patients operated on during 1987-93 and registered prospectively in the Swedish Vascular Registry, 62 cases of postoperative intestinal ischaemia were identified. They were compared with the remaining 2762 patients through the registry and with a random sample of 127 controls through patient records. Multivariate analysis was performed. RESULTS: Patients in shock operated on for ruptured aneurysms were at greatest risk of developing postoperative intestinal ischaemia. Excluding patients in shock, operation for aneurysmal disease and for occlusive disease carried the same risk. Renal disease, emergency surgery, age, type of hospital, aortobifemoral graft, operating time, cross-clamping time and ligation of one or both internal iliac arteries were independent risk factors. CONCLUSIONS: Patient-related haemodynamic risk factors together with surgical skill and decision making defines the risk for this serious complication.

Aged↗
PubMed1997

Long-term prognosis for patients with chronic leg ulcers: a prospective cohort study.

OBJECTIVES: To assess the long-term prognosis of leg ulcers. DESIGN: A 5 year prospective cohort study. MATERIALS: A random sample of 382 patients with open leg ulcers (foot ulcers included) treated in the community. METHODS: Interim analyses were made at 15 months (arterial ulcers) and at 20 months (varicose ulcers). Long-term healing was assessed at 54 months by a postal questionnaire. Five year survival was assessed by official population registries. RESULTS: At 54 months 212 patients (55%) were still alive, of whom 124 (58%) had healed their ulcers, 80 (38%) had open ulcers and eight (4%) were amputated. The healing was worst for patients with venous ulcers, only 44% had healed their original ulcers without recurrence. The 5 year survival was 52%, significantly lower than for age- and sex-matched controls (68%) (p = 0.0002). Patients with venous ulcers had a survival not significantly different from controls and patients with arterial or other aetiologies had a doubled risk of death. Diabetic patients had a lower survival than non-diabetics (p < 0.05) and controls (p < 0.0001), but the healing prognosis was not significantly different. CONCLUSION: Only patients with non-venous ulcers have a higher mortality than expected. The long-term healing prognosis for leg ulcer patients is poor and worst for patients with venous ulcers.

Adolescent↗
PubMed1997

Effects of vascular surgery on amputation rates and mortality.

OBJECTIVES: To study the relation between rates of vascular interventions, amputations and mortality in a defined population. DESIGN: Retrospective comparison between two consecutive 4-year periods. SETTING: Swedish district hospital covering a population of 125,000. MATERIAL: Three hundred and sixty-seven lower limb amputations and 1080 vascular procedures. RESULTS: The number of legs treated for limb-threatening ischaemia with either revascularisation or amputation increased from 269 to 289. The rate of vascular interventions for limb-threatening ischaemia increased from the first to the second period by 65%, while the rate of amputations decreased by 23%. Limb salvage rate at 30 months increased from 37% to 53% (p < 0.0000). The reduced amputation rate was entirely related to primary amputations. The adjusted risk of amputation for patients treated in the second period was half of that for patients treated in the first period (relative risk = 0.49, p = 0.0001), while mortality was similar in both periods. Among survivors, the proportion of patients with intact legs was higher in the second period than in the first, while no difference was found between the two periods among deceased patients. CONCLUSIONS: Increased vascular intervention leads to improved limb salvage rates and reduced amputation rates. It is important for both ethical and economical reasons to identify good responders to revascularisation, because the choice of initial treatment will only influence limb salvage but not survival.

Age Distribution↗
PubMed1997

Early attachment of leucocytes, platelets and fibrinogen in endothelial cell-seeded Dacron venous conduits.

BACKGROUND: There is a need for prosthetic venous conduits in surgery for trauma, cancer and thrombotic disease. Such conduits in use today have a low patency rate, leaving room for much improvement. METHODS: This experimental study investigated the dynamics of the early attachment of radiolabelled platelets, leucocytes and fibrinogen to endothelial cell-seeded Dacron venous conduits in sheep. Grafts were placed as jugular vein interposition grafts, seeded on one side, not seeded on the other, and followed for 4 h. RESULTS: No difference could be demonstrated between the two graft types. Platelets showed an increasing attachment during the whole period, leucocytes an immediate attachment followed by an undulating pattern, and fibrinogen an immediate attachment with a tendency to decrease. Measurements on the vein itself showed a high attachment and, for platelets, an extremely high attachment when measured after the graft in the direction of flow. CONCLUSION: The seeding process did not seem to affect early thrombogenicity. The carefully dissected vein wall showed highly thrombogenic properties, in many ways as high as in the prosthetic graft.

Animals↗
PubMed1997

Prolonged prophylaxis in postoperative medicine.

Major surgical procedures, especially orthopedic surgeries, such as elective hip or knee replacement, are associated with a high incidence of postoperative deep vein thrombosis (DVT) and potentially fatal pulmonary embolism (PE). Although most surgeons exercise thromboprophylaxis, the length of time of prophylactic measures is at this time uncertain. With increasing shortening of in-hospital stays and thus shorter times of prophylaxis, increasing numbers of "late" PE are being recognized. These observations have raised the issue of postdischarge continuation of prophylaxis. This problem was recently addressed by four studies involving hip arthroplasty patients. In all trials prophylaxis was performed with low-molecular-weight heparins (LMWH). Two studies used enoxaparin, two used dalteparin. Duration of in-hospital treatment lasted from 7 to 15 days. The length of postdischarge prophylaxis ranged from 21 to 28 days. DVT was diagnosed by bilateral venography. In all instances there was a significant reduction in DVT in the treated patient group, compared with those who were not treated after discharge. It is assumed that this reduction also impacts the frequency of potentially fatal PE. The trials suggest that thrombosis prophylaxis should be continued in patients following discharge from hospital after major surgical procedures, especially when risk factors persist.

Adult↗
PubMed1997

Antithrombotic and platelet activating effects of heparin in prevention of microarterial thrombosis.

It has been proposed that the limited effectiveness of heparin in preventing arterial thrombosis may be caused by heparin-mediated platelet activation. The effect of heparin on platelets and thrombus formation in vivo was investigated using a microarterial model of thrombosis involving registration of labeled platelets. Three groups of six rabbits each were treated with either saline, standard heparin, or heparin with low affinity for antithrombin III (LA-heparin), which exhibits a low anticoagulant potential but has a molecular weight distribution similar to standard heparin. (Fifty to 70 percent of standard heparin consists of low-affinity material). The heparins were infused intravenously at doses of 1 mg/kg body weight, followed by maintenance injections. Platelet accumulation was significantly increased in the LA-heparin group compared with the saline group, demonstrating heparin-induced platelet activation in vivo. In contrast to a powerful anticoagulant response observed in rabbit plasma, the antithrombotic effect of standard heparin was expressed incompletely. (Only two of three of the treated vessels remained patent). This study demonstrates heparin-induced platelet activation in vivo in conditions of platelet-mediated thrombus formation. The observations are consistent with the concept of heparin-induced platelet activation as one of the mechanisms explaining the limited effects of heparin in preventing arterial thrombosis.

Animals↗