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Biomedical subjects

D Bergqvist

Publications and source records attributed to D Bergqvist.

At least 685 records · Page 38Linked to original sources
PubMedDate not supplied

Prostacyclin release from the human saphenous vein in diabetics in lower than in nondiabetics.

The balance between prostacyclin and thromboxane has been suggested to be of great importance for the maintenance of patency in veins. In order to investigate prostacyclin and thromboxane release, segments from the human saphenous veins were investigated in 53 patients. Twenty-seven patients (10 males, 17 females) underwent surgery for varicose veins. Twenty-six patients (14 nondiabetics, 12 diabetics) underwent surgery for lower limb ischemia (rest pain or gangrene) with use of the saphenous vein as arterial conduit. Vein segments were gently excised and perfused ex vivo for five 15 minute periods, with a balanced salt solution and determination of the stable degradation products 6-keto-PGF1 alpha and TxB2. Saphenous veins from patients with varicose veins had an initial prostacyclin release of 61 +/- 13 pg/mm2/15 min declining to 4 +/- 1 pg/mm2/15 min after 60 min (p < 0.001) and increasing after addition to arachidonic acid to 37 +/- 7 pg/mm2/15 min (p < 0.001). Segments from nondiabetic patients with lower limb ischemia did not differ from those of varicectomy patients, but diabetic segments had a significantly lower prostacyclin release than both these groups, 34 +/- 11 pg/mm2/15 min, 1 +/- 1 pg/mm2/15 min, and 7 +/- 5 pg/mm2/15 min, respectively (p < 0.05). The addition of arachidonic acid failed to increase the prostacyclin release in diabetics. Three patients from each group were studied regarding thromboxane release and there was almost no detectable thromboxane in any group. These findings suggest that diabetics have a lowered prostacyclin release from the saphenous vein and that the deficiency is at the cyclo-oxygenase level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Cost-effectiveness of prolonged administration of a low molecular weight heparin for the prevention of deep venous thrombosis following total hip replacement.

Recently there has been discussion on the value of prolonged thromboprophylaxis after elective hip surgery to prevent thromboembolic complications up to one month. Continuing low molecular weight heparin for one month can significantly reduce the frequency of venographically-proven deep vein thrombosis (DVT). How this will influence health economics has hitherto not been evaluated. Data on costs and effect from a randomized comparison between 10 and 30 days of once daily low molecular weight heparin (enoxaparin) were used in a cost-effectiveness study. Data on treatment costs were based on patients actually treated for DVT within the randomized study. Various sensitivity analyses were performed. In the study both phlebographically detected and clinically manifested venous thromboembolism were registered. By using costs from the health care system in Sweden it could be shown that the cost was 6,075 Swedish Krona (SEK) per phlebographic DVT avoided and 13,184 Swedish Krona (SEK) per clinical DVT avoided. If more than 50% of the patients managed to self-administer the low molecular weight heparin injections, the use of prolonged prophylaxis is cost-effective. Prolonged prophylaxis with the low molecular weight heparin enoxaparin after elective hip arthroplasty is cost-effective provided that at least 50% of the patients can administer the subcutaneous injections themselves.

Journal Article↗
PubMedDate not supplied

Prevention of experimental venous thrombosis in rabbits with different low molecular weight heparins, dermatan sulphate and hirudin.

In a randomized, blind study the antithrombotic efficacy of dermatan sulphate (DS), recombinant hirudin (r-hirudin) and four commercially available low molecular weight heparins (LMWHs) was investigated after intravenous administration in a jugular vein thrombus model in rabbits utilizing a combination of endothelial damage and flow reduction. The parameters observed were the frequency of visible thrombosis, the frequency of occlusive thrombosis and thrombus weights. DS and r-hirudin were investigated in one fixed dose and the LMWHs in prophylactic doses, adjusted to body weight, recommended in high-risk situations by the manufacturers. All substances effectively reduced the three observed parameters. DS and r-hirudin were equally or even more effective than the LMWHs. Although significant differences were not found between the individual LMWH treatments a visible trend cannot be overlooked in all three observed parameters. This cannot solely be explained by the different antifactor Xa activity doses given but increased antithrombotic activity was observed with declining antifactor Xa/antifactor IIa ratio. Our findings indicate that the different commercial LMWHs may differ in their antithrombotic activity when given in recommended doses adjusted to body weight in this experimental model. Dose range studies are required to clarify the thromboprophylactic efficacy of DS and r-hirudin in relation to the tested LMWHs.

Animals↗
PubMedDate not supplied

The haemorrhagic effect of low molecular weight heparins, dermatan sulphate and hirudin.

In a randomized, blind study the primary effect on haemostasis after intravenous administration of dermatan sulphate (DS), recombinant hirudin (r-hirudin) and four commercial low molecular weight heparins (LMWHs) (nadroparine, enoxaparin, dalteparin and tinzaparin) was investigated in rats and compared with saline (control). The tail bleeding time, the bleeding from the gastric mucosa [the mucosal bleeding time (min) and the mucosal bleeding (microliter)] as well as changes in activated partial thromboplastin time, antifactor IIa and Xa activities were investigated. DS and r-hirudin were investigated in a dose potentially suitable in thomboprophylaxis and the LMWHs in doses recommended by the manufacturers for thromboprophylaxis, adjusted to body weight. All substances significantly prolonged the mucosal bleeding time. Dalteparin, tinzaparin, DS and r-hirudin increased the mucosal bleeding when compared with controls whereas nadroparine and enoxaparin did not. The effect of r-hirudin was also significantly more pronounced compared with other treatments. Moreover, r-hirudin prolonged the tail bleeding time significantly whereas the other substances did not. The antifactor Xa activity in plasma correlated well with the given dose of the LMWHs (rs = 0.7). However, the monitored bleeding parameters in the LMWH groups did not correlate with the plasma activities of antifactor IIa or Xa. The results indicate that the tested LMWHs are not equipotent in their effect on haemostasis in this model and that antifactor IIa or Xa activities do not directly correlate with their effect on haemostasis although increased haemorrhage was observed in the LMWHs with lower antifactor Xa/antifactor IIa ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Fatal thrombo-embolic complications at aorto-femoral angiography.

Fatal complications due to angiographic procedures are rare. An awareness of these complications is, however, mandatory in order to be able to prevent them. This report concerns three fatal cases with a deleterious complication of distal macro- and microembolization in connection with the angiographic procedure. In all cases the local circulation was surgically restored. The microcirculation was 'out of reach' and all three patients succumbed with profound tissue ischemia.

Aged↗
PubMedDate not supplied

Acute renal failure in rats. Interaction between a contrast medium and renal arterial occlusion.

Acute renal failure is a serious complication of reconstructive aortoiliac surgery. The question was raised whether its etiology includes interaction between preoperative angiographic contrast medium and intra-operative clamping of the renal arteries. Renal arteries of 180 rats were bilaterally clamped 10 to 120 min and serum urea was determined from 3 h to 7 days later. In 35 rats 40 min clamping alone produced an increase in urea reaching a maximum 1 day later (median increase 70%). In 3 groups of 12 rats intravenous injection of the contrast medium metrizoate alone in doses 1, 2 and 3 g I/kg body-weight produced no significant increase in urea. Intravenous injection of the same doses to 3 groups of 10 rats each followed 1 h later by renal arterial occlusion for 40 min produced median urea increases one day later of 110, 130 and 170 per cent, respectively, in the 3 groups. The increase was higher than that produced by contrast medium alone (p less than 0.01) or by renal artery clamping alone (p less than 0.05) indicating a potentiation of transient renal failure by the combination of contrast medium and renal arterial clamping.

Acute Kidney Injury↗
PubMedDate not supplied

Steal syndrome after brachiocephalic fistula for vascular access: correction with a new simple surgical technique.

PURPOSE: Steal syndrome is the condition of arterial insufficiency distal to a permanent haemodialysis fistula. Three treatment options have been recommended: ligation of the fistula, banding of the fistula, and distal revascularization. We report an alternative simple surgical technique for correction of steal syndrome. METHODS: Two patients were treated for steal syndrome after brachiocephalic fistula operation. The treatment of the steal syndrome was done by interponating an ePTFE graft loop tunnelated subcutaneously in the upper arm. RESULTS: At follow-up one year later both fistula were patent without any reoperation and with normal flow at haemodialysis. There were no symptoms of steal. CONCLUSION: This new method for correction of steal syndrome seems to be an attractive alternative.

Journal Article↗
PubMedDate not supplied

Steal syndrome of the hemodialysis vascular access: diagnosis and treatment.

PURPOSE: Steal syndrome is an uncommon but serious condition of arterial insufficiency distal to a permanent hemodialysis fistula. The management of the condition is a great challenge to the surgeon because of the conflicting goals of preserving the fistula and treat the ischemia. In this review the purpose was to analyze the clinical problem and treatment possibilities. METHODS: Medline and Embase databases were searched for studies relevant to diagnosis and management of steal syndrome of the hemodialysis vascular access. RESULTS: The diagnosis of steal syndrome is largely based on clinical features and non-invasive studies. In same cases angiography may be necessary to find out the real causes of the steal syndrome. The cause is usually high fistula flow but other causes as steal phenomenon, inflow, outflow or anastomotic stenosis have to be considered and even combination of causes. The main treatment options are some form of flow reducing procedure or the distal revascularization interval ligation method. In some cases simple distal arterial ligation is the method of choice. Furthermore, in some patients a stenosis has to be treated as the first treatment option. CONCLUSIONS: For an appropriate treatment of a steal syndrome a careful analysis of the cause is important.

Journal Article↗
PubMedDate not supplied

The influence of distal runoff on patency of infrainguinal vein bypass grafts.

This retrospective study was conducted to analyze a new concept of evaluation of the effect of distal runoff on patency in infrainguinal bypass surgery for arterial insufficiency. Distal runoff was evaluated on postreconstruction angiograms in 191 limbs undergoing femoropopliteal and femorodistal reconstruction. Runoff was characterized as good, fair, or poor. Determination of graft patency was made by clinical examination, ankle-brachial index measurement, or duplex scanning at 1 month and thereafter at 6-month intervals. Cumulative patency rates were calculated according to the actuarial life table method. Patency rates in limbs with good runoff were better than in limbs with fair and poor runoff; at 6 months, patency rates were 88.2%, 70.9%, and 21.8%, respectively (p < 0.01). Similar patency rates were found for good runoff in femoropopliteal and femorodistal reconstructions (84.7% in femoropopliteal and 75% in femorodistal reconstructions) at 6 months. The authors conclude that this method of angiographic evaluation accurately predicts patency in infrainguinal bypass reconstructions.

Adult↗
PubMedDate not supplied

Peroperative arterial recanalization with Kensey dynamic angioplasty. Histopathologic studies.

The morphology of occluded superficial femoral artery segments and of particles in the effluent fluid after dynamic Kensey catheter angioplasty was analyzed in six patients treated with an intraoperative retrograde technique. The effluent was collected during the procedure and the arteries were extirpated for microscopy after the recanalization attempt. In three patients with easy recanalization, histologic study showed highly cellular, proliferating connective tissue. In three patients with unsuccessful recanalization, mature, cell-poor connective healing tissue obliterated the lumen. The effluent contained particles measuring 14 to 320 microns, the largest of which had the potential to occlude small arteries. The results of this pilot study are to be regarded as preliminary.

Aged↗
PubMedDate not supplied

Low molecular weight heparin compared with dextran as prophylaxis against thrombosis after total hip replacement.

The effect of low molecular weight (LMW) heparin given once daily as prophylaxis against venous thrombosis was compared with that of dextran 70 in an open randomised trial of 100 patients undergoing elective total hip replacement. Four patients were withdrawn after randomisation and thus 96 were included in the final analysis. The development of thrombus was surveilled by the 125I fibrinogen test, and positive readings were verified by venography. Nine of 47 patients given LMW heparin developed thromboses (19%) compared with 18 of 49 given dextran (37%) (p = 0.09). Two further patients who received LMW heparin developed thromboses after leaving hospital (clinical signs became apparent on days 13 and 17, respectively), giving an overall rate of thrombosis in this group of 23%. Minor wound haematomas occurred in two of 47 in the LMW heparin group and three of 49 in the dextran group (4% and 6%, respectively), and blood loss, transfusion requirements, and reduction in postoperative haemoglobin concentration did not differ between the two groups. The studied LMW heparin given subcutaneously once a day was no less safe or effective than dextran in preventing thromboembolism after total hip replacement.

Aged↗
PubMedDate not supplied

Dextran and release of prostacyclin from ex vivo perfused rabbit arteries and veins.

The effects of dextran on the haemostatic system lead to prolongation of the bleeding time. To observe if the coating of endothelial cells by dextran influences the release of prostacyclin from the vessel walls in response to ex vivo perfusion, dextran 70 (1 g/kg b.w.) was given i.v. 15 min or 4 hours before excision of caval vein and aorta in rabbits, or was added to the perfusate. Vascular segments were perfused for 5 x 15 min, with the perfusate changed after each period and with arachidonic acid added on the last occasion. Prostacyclin was measured as its stable degradation product 6-keto-PGF1 alpha by radioimmunoassay. Arteries released more prostacyclin than did veins (p less than 0.01). Dextran given in vivo or ex vivo had no influence on release of prostacyclin from the walls of perfused arteries or veins. The anti-haemostatic properties of dextran 70, 1 g/kg b.w., thus do not seem to be mediated by prostacyclin release from vessel walls.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Acute renal failure in rats. Interaction between contrast media and temporary renal arterial occlusion.

It was demonstrated in rats that renal injury which follows transient renal hypoxia is potentiated by the contrast media metrizoate, ioxaglate, iopamidol and iohexol. Intravenous injection of 1 g I/kg of all four media alone to 82 rats caused no significant increase in serum urea 1, 3 and 7 days later. The percentage increase of serum urea is given in median values and interquartile range (in parentheses). Bilateral renal arterial occlusion alone for 40 minutes in 42 rats increased serum urea one day later by 40 per cent (20-130). Intravenous injection of the media followed in one hour by bilateral renal arterial occlusion for 40 minutes in 104 rats caused serum urea to increase one day later by 130 per cent (70-350) after metrizoate, by 220 per cent (50-380) after ioxaglate, by 290 per cent (60-420) after iopamidol and by 160 per cent (50-330) after iohexol. There were no significant differences between the potentiating effects of the various media on ischemic renal failure.

Acute Kidney Injury↗
PubMedDate not supplied

Lower limb oedema after arterial reconstructive surgery. Influence of preoperative ischaemia, type of reconstruction and postoperative outcome.

To investigate the early limb oedema after various types of arterial reconstructions 180 patients operated on due to occlusive or aneurysmatic arterial disease were followed by daily circumference measurements of the lower leg. For volume calculations circumference measurements were shown to be well correlated to water displacement volumetry. Femoro-popliteal bypass resulted regularly in a pronounced oedema, significantly more than in any of the other groups. Aortofemoral reconstruction did not lead to significant leg oedema, but all other reconstructions resulted in a volume increase in the symptomatic leg. Following distal reconstruction, patients with popliteal aneurysm and no ischaemia developed the same maximal volume increase as patients with severe ischaemia. Regarding all patients as one group the volume increase was not significantly correlated to the preoperative ankle blood pressure or ankle brachial pressure index. Only after various proximal reconstructions, with a limited postoperative oedema, there was a correlation between the degree of preoperative ischaemia and postoperative volume increase. A successful reconstruction was not necessary for the development of postoperative oedema. A failed distal reconstruction was followed by a significant oedema, although less pronounced than after a successful. Exploration of the vessels without reconstruction also led to a postoperative oedema. The findings indicate that the pathogenesis of postreconstructive oedema is multifactorial. The type of reconstruction is the most important predictive factor and degree of preoperative ischaemia and success of operation are contributing factors.

Aneurysm↗
PubMedDate not supplied

Complications after percutaneous transluminal angioplasty of peripheral and renal arteries.

This review deals with complications after percutaneous transluminal angioplasty (PTA). First some methodologic points are discussed. It seems important to standardize the way in which complications are reported. Our own complications in peripheral and renal PTA are summarized and taken as a basis for an analysis of various types of complications. Principally these may occur at different levels: at the puncture site, at the dilatation site as well as distant and general complications. To make comparisons with surgical series relevant it is suggested that all complications and mortality within 30 days are reported.

Angioplasty, Balloon↗
PubMedDate not supplied

Does cerebral angiography of cadaveric kidney donors interfere with graft function?

Cerebral angiography is used to diagnose brain death of cadaver kidney donors. Clinical and animal data suggest that angiographic contrast media may potentiate the noxious effect of renal ischemia. In order to find out if cerebral angiography of cadaveric kidney donors prior to nephrectomy interferes with function or survival of the renal grafts, two groups of cadaveric donors were compared. One group had been exposed to contrast medium from cerebral angiography in median 18 hours before nephrectomy and the other had not. There was no difference in graft survival and function between the two groups. In a previous investigation angiography was performed two hours before explantation and in that investigation there was a shorter graft survival in the angiography group than in a control group. A delay of 12 hours is suggested between cerebral angiography and explanation, to decrease the combined harmful effects of contrast media and ischemia on renal grafts.

Adolescent↗