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Biomedical subjects

D Bergqvist

Publications and source records attributed to D Bergqvist.

At least 55 records · Page 3Linked to original sources
PubMed2001

Timing of initial administration of low-molecular-weight heparin prophylaxis against deep vein thrombosis in patients following elective hip arthroplasty: a systematic review.

BACKGROUND: Perioperative and postoperative venous thrombosis are common in patients undergoing elective hip surgery. Prophylactic regimens include subcutaneous low-molecular-weight heparin 12 hours or more before or after surgery and oral anticoagulants. Recent clinical trials suggest that low-molecular-weight heparin initiated in closer proximity to surgery is more effective than the present clinical practice. We performed a systematic review of the literature to assess the efficacy and safety of low-molecular-weight heparin administered at different times in relation to surgery vs oral anticoagulant prophylaxis. METHODS: Reviewers (A.F.M. and S.M.M.) identified studies by searching MEDLINE, reviewing references from retrieved articles, scanning abstracts from conference proceedings, and contacting investigators and pharmaceutical companies. Randomized trials comparing low-molecular-weight heparin administered at different times relative to surgery with oral anticoagulants in patients undergoing elective hip arthroplasty, evaluated using contrast phlebography, were selected. Two reviewers (A.F.M. and S.M.M.) extracted data independently. RESULTS: The literature review identified 4 randomized trials meeting predefined inclusion criteria. The results indicate that low-molecular-weight heparin initiated in close proximity to surgery resulted in absolute risk reductions of 11% to 13% for deep vein thrombosis, corresponding to relative risk reductions of 43% to 55% compared with oral anticoagulants. Low-molecular-weight heparin initiated 12 hours before surgery or 12 to 24 hours postoperatively was not more effective than oral anticoagulants. Low-molecular-weight heparin initiated postoperatively in close proximity to surgery at half the usual dose was not associated with a clinically or statistically significant increase in major bleeding rates (P =.16). CONCLUSIONS: The timing of initiating low-molecular-weight heparin significantly influences antithrombotic effectiveness. The practice of delayed initiation of low-molecular-weight heparin prophylaxis results in suboptimal antithrombotic effectiveness without a substantive safety advantage.

Administration, Oral↗
PubMed2001

Validation of in vivo noninvasive high-frequency ultrasonography of the arterial wall layers.

To validate estimates of the arterial wall thickness and its separate layers, 19 superficial (7 femoral and 12 cutaneous) arteries were transcutaneously sonographed in 13 anaesthetized pigs with a high-resolution equipment fitted with a 25 MHz frequency probe. Means of ultrasonographic estimates of each wall layer were compared with those obtained from microscopy of the respective arterial specimens taken after the pigs were sacrificed. For all vessels combined, Spearman-rank correlation tests between ultrasonography and histology estimates were significant for total arterial wall thickness (r(s) = 0.78; p =.0001) but not for the separate layers. For the cutaneous arteries, a significant correlation was found for total arterial wall thickness (r(s) = 0.69; p =.01) and media layer (r(s) = 0.76; p =.004). The method seems to give valid estimates of both total arterial wall and media thickness in superficial arteries, but to be less accurate for estimate the adventitia and intima layers.

Animals↗
PubMed2001

Coagulation and fibrinolysis in chronic venous insufficiency.

BACKGROUND: Varicose veins (VV) are common, but only some patients will develop chronic venous insufficiency (CVI) with skin changes or venous ulcer. The pathophysiology of venous ulcer development is complex, and may involve abnormalities in coagulation, fibrinolysis and proinflammatory cytokines. The purpose of this study was to correlate plasma markers within these systems and skin pathology. METHOD: A group of twenty consecutive patients with active or recent venous ulcer were matched for sex and age with further three groups of individuals i.e. controls and patients with VV with and without skin changes respectively. Blood samples were analysed for hemoglobin (HB), total platelet count (TPC), C-reactive protein (CRP), activated partial thromboplastin time (APTT), prothrombin complex (PT), fibrinogen, interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), D-dimer, tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), prothrombin fragments 1 and 2 (F1 + 2), and thrombin antithrombin III complex (TAT). RESULTS AND CONCLUSION: There was an increase of systemic levels of PAI-1 activity and tPA with progressive skin pathology in patients with CVI, and in the group with active ulcer there was an elevation of F1 + 2. Those findings could reflect a defect fibrinolysis, a thrombotic potential or a damaged endothelium.

Aged↗
PubMed2001

Low molecular weight heparin (enoxaparin) versus dextran in the prevention of early occlusion following arterial bypass surgery distal to the groin.

AIM: to compare the effect of perioperative dextran and low molecular weight heparin on early graft patency after femorodistal bypass surgery. DESIGN: prospective randomised multicentre study. PATIENTS AND METHODS: three hundred and fourteen patients were randomised to dextran 70 or the low molecular weight heparin enoxaparin during and after femorodistal bypass surgery. Patency was evaluated at days 1, 5-7, 30 and 90. RESULTS: there was no difference in patency at any time point between the two regimens, the crude 90 days patency being 88 and 83%, respectively. There were significantly more patients with heart failure in the dextran group (12.8 vs 0.7%), with other side effects being evenly distributed. CONCLUSION: dextran 70 and the low molecular weight heparin enoxaparin have the same effect on 90 days femorodistal graft patency, but care must be taken using the dextran to patients with a potential heart insufficiency.

Anticoagulants↗
PubMed2001

Literature review of surgical management of abdominal aortic aneurysm.

OBJECTIVES: To review the natural history and the outcome of surgical repair of aortic abdominal aneurysm (AAA). DESIGN: An English and Scandinavian language search of papers between 1985-1997. RESULTS: After review, 132 papers with 54 048 patients remained. The mean postoperative mortality (30 days or in-hospital) for elective repair was approximately 5% and for emergency operations 47% (range 27-69%), both with significant heterogeneity. Results did not improve over time. Increasing age, presence of renal failure and atherosclerotic cardiac disease were identified as pre-operative risk factors. AAA expansion averaged 0.2-0.4 cm per year for aneurysms smaller than 4 cm, 0.2-0.5 cm for aneurysms 4-5 cm and 0.3-0.7 cm for those larger than 5 cm. The rupture risk at four years was 2, 10 and 22% respectively. The overview revealed several methodological problems in the reported studies. CONCLUSIONS: The results can be used as the basis of quality assurance or in decision trees or other models. Better reporting standards are needed.

Adolescent↗
PubMed2001

Arterio-ureteral fistula--a systematic review.

OBJECTIVE: To review published reports on arterio-ureteral fistula. METHOD: Literature search. RESULTS: Eighty cases were identified. Primary fistulas were mainly seen in combination with aortoiliac aneurysmal disease. Secondary fistulas were seen after pelvic cancer surgery, often with radiation, fibrosis and ureteral stenting or after vascular surgery with synthetic grafting. The dominating symptom is massive haematuria, often with circulatory impairment. The clue to a rapid and correct diagnosis is a high degree of suspicion. Most frequently diagnosis has been obtained through angiography or pyelography. When there is a ureteral stent manipulation it will often provoke bleeding and lead to diagnosis. The fistula must be excluded and a vascular reconstruction made. Most frequently this has been obtained through occlusion of the fistula and an extra-anatomic reconstruction (femoro-femoral crossover). Recently stent-grafting has been successfully used but follow-up is short. CONCLUSION: Arterio-ureteral fistula is rare and should be suspected in patients with complicated pelvic surgery and massive haematuria, especially where rigid ureteral stents have been placed.

Adolescent↗
PubMed2001

Floating nonocclusive thrombus in the common femoral artery detected by duplex scanning after removal of the arterial catheter: a case report.

A 5-year-old girl is reported in whom duplex scanning showed a nonocclusive thrombus in the common femoral artery that was removed successfully by surgical intervention. Noninvasive examination with duplex scanning in patients with signs of acute arterial insufficiency during or after removal of femoral artery catheter is recommended.

Catheterization↗
PubMed2001

Monitoring of intrathecal oxygen tension during experimental aortic occlusion predicts ultrastructural changes in the spinal cord.

OBJECTIVE: To study the correlation between intrathecal PO2 and ultrastructural changes in the spinal cord during thoracic aortic occlusion in pigs. MATERIAL AND METHODS: In 18 pigs, online intrathecal oxygenation was monitored by a multiparameter Paratrend catheter (Biomedical Sensors, High Wycombe, United Kingdom) during 60 minutes' clamping of the proximal and distal descending thoracic aorta. The animals were randomly divided into 2 groups (A and B) depending on the level of distal aortic clamping. Distal aortic perfusion was restored through an aorto-iliac shunt, which also maintained low thoracic segmental perfusion of the spinal cord in group B. Perfusion-fixation technique was used before harvesting the spinal cord specimens, which later were evaluated with light and electron microscopy by an independent observer. Intrathecal parameters were interpreted as normal if PO2 was more than 0.8 kPa and PCO2 was less than 12 kPa, as intermediate ischemia if PO2 was 0.8 or less or PCO (2) was more than 12 kPa, and as absolute ischemia if PO2 was 0.8 or less and PCO2 was more than 12 kPa. RESULTS: Among 6 animals with ultrastructural changes of absolute spinal cord ischemia-reperfusion injury, 5 also had absolute ischemia according to variables derived by the Paratrend catheter. The 2 methods were in agreement in 3 of 5 animals with intermediate ischemia-reperfusion changes and in 5 of 6 animals with normal findings. The accuracy of cerebrospinal fluid PO2 and PCO2 to predict electron microscopy-verified intermediate or absolute ischemia-reperfusion injury was 94%. CONCLUSIONS: Monitoring of intrathecal PO2 after clamping of the descending aorta correlated with ultrastructural changes in the spinal cord in this pig model.

Animals↗
PubMed2001

Aspects of the spinal cord circulation as assessed by intrathecal oxygen tension monitoring during various arterial interruptions in the pig.

OBJECTIVE: We sought to study the effect of various modes of interruption of the spinal cord blood supply on intrathecal oxygenation. METHODS: In 24 pigs intrathecal PO (2), PCO (2), and pH were continuously monitored with a multiparameter catheter (Paratrend 7, Biomedical Sensors; Diametrics Medical, Inc, St Paul, Minn) during and after aortic crossclamping or selective interruption of segmental arteries and proximal collateral circulation. RESULTS: Proximal aortic clamping (n = 6) produced complete ischemia, whereas a second clamp close to the celiac trunk (n = 4) partly protected against spinal cord ischemia. This is explained by prevention of the steal phenomenon in the excluded part of the aorta. Adding clamps to the subclavian arteries (n = 6) created complete spinal ischemia as the collateral circulation was interrupted. In another group (n = 4) all segmental arteries below T5 were occluded with no reaction in the intrathecal variables. Additional selective clamping of supreme intercostal arteries (n = 4) showed the relative importance of the subclavian and vertebral collateral pathways. CONCLUSIONS: Continuous intrathecal PO (2) was monitored during various modes of interruption of the spinal cord blood supply. This provided insight into the ischemia mechanisms and relative importance of the segmental contribution and proximal collateral pathways of the spinal cord circulation in pigs. A short literature review is given, and aspects of comparative anatomy are discussed.

Animals↗
PubMed2001

Influence of diagnostic criteria on the prevalence of abdominal aortic aneurysm.

PURPOSE: We studied the prevalence of abdominal aortic aneurysm (AAA) in a population with high incidences of cardiovascular diseases and analyzed how the prevalence varies according to methodology and criteria. METHODS: All men and women aged 65 to 75 years who lived in the Norsjö municipality in northern Sweden were invited to undergo an ultrasound scanning (US) examination. Those with an aortic diameter of 28 mm or more or with poor visibility on US were examined with computed tomography scanning (CT). Various recommended AAA definitions, two diagnostic methods (US and CT), and two diameters (maximum and anteroposterior) were analyzed. RESULTS: Of 555 people invited to participate in the study, 504 accepted (248 men and 256 women; 91%). Eight subjects had undergone surgery for an AAA. Ninety-two subjects underwent CT. The mean maximum infrarenal aortic diameter was 24.6 mm (by means of US). Depending on diagnostic criteria, the AAA prevalence was 3.6% to 16.9% in men and 0.8% to 9.4% in women. Depending on which previous study was used as a comparison and the definition of AAA and diagnostic technique used, the prevalence in this study was 1.3 to 4.0 times higher for men and 2.0 to 5.8 times higher for women. CONCLUSION: In a region in which residents have a high risk for cardiovascular disease, we found the highest prevalence of AAA ever reported within a population. The prevalence highly depends on methodology and diagnostic criteria, with a 10-fold variation. Detailed defined criteria are necessary to permit comparisons between studies: the number of individuals who have undergone surgery for AAA and whether they are included, the prevalence in 5- and 10-year age intervals, attendance rate, visibility, which diameter(s) is measured, and the prevalences with as many as possible of the four described definitions of AAA. The etiology of the high prevalence of AAA in this population needs to be investigated further.

Aged↗
PubMed2001

Increased FiO2 improves intrathecal oxygenation during thoracic aortic cross-clamping in pigs.

OBJECTIVES: To investigate the effect of 100% oxygen ventilation on cerebrospinal fluid (CSF) oxygenation in 11 pigs during thoracic aortic cross-clamping. DESIGN: An aorto-aortic shunt was used for control of central hemodynamics and study of hypoperfusion by exsanguination. CSF PO2, PCO2 and pH were continuously monitored before and during clamping. The changes in hemodynamic parameters and intrathecal gas tensions in response to variations in proximal mean aortic pressure and fraction of inspired oxygen (FiO2) were recorded. RESULTS: Baseline CSF PO2 decreased from 4.8 +/- 1.9 to 2.6 +/- 2.2 kPa following aortic occlusion. Increasing FiO2 to 1.0 resulted in a significant increase in CSF PO2 to 4.1 +/- 3.0 with a return to 2.7 +/- 2.1 kPa after reducing FiO2 to 0.4 again. The same variations in FiO2 did not induce any significant changes in CSF PO2 during hypotension. CONCLUSION: Increased FiO2 during experimental thoracic aortic cross-clamping with stable proximal arterial pressure helps to maintain CSF PO2, whereas severe hypotension could not be compensated for by hyperoxemia.

Animals↗
PubMed2001

Cost effectiveness of desirudin compared with a low molecular weight heparin in the prevention of deep vein thrombosis after total hip replacement surgery.

OBJECTIVES: This prospective pharmacoeconomic study analyses and discusses the cost effectiveness (expressed as cost per life-year gained) of desirudin in comparison with a low molecular weight heparin (LMWH), enoxaparin, as prophylaxis against deep vein thrombosis (DVT) in total hip replacement. METHODS: The cost effectiveness was analysed on the basis of results from a clinical trial that compared the recombinant hirudin, desirudin, with the LMWH, enoxaparin. The trial results regarding the incidence of DVT are included together with epidemiological data in a decision tree, simulating long term cost effectiveness of patients undergoing elective hip replacement. The model includes Markov processes simulating patients up to the age of 85 years, including the costs of DVT-related long term complications. RESULTS: The average total thrombosis-related cost per patient under prophylactic therapy with enoxaparin is 7,022 Swedish kronor (SEK) compared with SEK7,497 when using desirudin (1998 values). The total costs with desirudin are 7% higher. Prophylaxis with desirudin in those patients undergoing elective hip replacement surgery adds, on average, 7 days of life per patient when compared with treatment using enoxaparin. This is equivalent to 1.91 additional years of life per 100 patients treated. The incremental cost-effectiveness ratio of prophylaxis with desirudin in patients undergoing elective hip replacement surgery is SEK24,864 per life-year gained in comparison with enoxaparin. CONCLUSION: The present study demonstrates that prophylactic therapy with desirudin is a cost-effective approach for the prevention of DVT in patients undergoing total hip replacement.

Aged↗
PubMed2001

Influence of low proximal aortic pressure on spinal cord oxygenation in experimental thoracic aortic occlusion.

BACKGROUND: To evaluate the effect of low proximal aortic pressure on cerebrospinal fluid (CSF) oxygenation in an experimental thoracic occlusion model. METHODS: In nine pigs, continuous intrathecal pO(2), pCO(2) and pH monitoring was used during double descending thoracic aortic clamping following insertion of an aorto-aortic shunt. In five pigs, the shunt was connected to a citrated bag adjusted at approximately 40-45 cm above the heart for partial exsanguination in order to decrease mean proximal aortic pressure (MPAP) to below 50 mmHg. In four animals, sodium nitroprusside infusion was used for this purpose. RESULTS: Intrathecal pO(2) demonstrated a significant decrease from 4.9+/-2.1 to 2.9+/-2.4 kPa after 10 minutes of aortic cross-clamping. Lowering proximal aortic pressure caused a further significant decrease to 1.2+/-1.7 kPa (p<0.05). In seven pigs (5 in the exsanguination and 2 in the vasodilator group), restoration of mean proximal aortic pressure to 94.0+/-27.7 caused a recovery of CSF pO(2) from 1.2+/-1.9 to 2.8+/-3.0 (p<0.05). CONCLUSIONS: The results of this study demonstrate that MPAP which provides spinal cord perfusion through subclavian-vertebral arteries are crucial for maintenance of spinal cord oxygenation during thoracic aortic occlusion in this pig model.

Animals↗
PubMed2000

[Caution for prophylaxis of thrombosis in connection with spinal anesthesia. Risk of hemorrhage when low-molecular-weight heparin is administered in epidural/spinal anesthesia].

There is an increasing awareness of the risk of haematoma in patients anticoagulated with low molecular weight heparins and scheduled to undergo epidural or spinal anaesthesia. The mechanisms causing this are not always clear, the incidence is very low. Risk factors are discussed as well as possible precautions to avoid this iatrogenic complication.

Analgesia, Epidural↗