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Biomedical subjects

B Lindblad

Publications and source records attributed to B Lindblad.

At least 19 recordsLinked to original sources
PubMed1995

Femoropopliteal-crural graft patency is improved by an intensive surveillance program: a prospective randomized study.

PURPOSE: The purpose of this study was to evaluate whether intensive surveillance compared with routine follow-up examinations improves femoropopliteal/crural graft patency. METHODS: After operation the patients were randomized to intensive (n = 79) or routine surveillance (n = 77). The groups were matched with regard to sex, diabetes, indication for surgical procedure, surgical procedure, and graft material. Intensive surveillance was clinical examination, ankle/brachial index measurements, and duplex scans 1, 3, 6, 9, 12, 15, 18, 21, 24, and 36 months after operation. Routine surveillance was clinical examination and ankle/brachial index measurements without duplex scanning 1, 12, 24, and 36 months after operation. Grafts with a decrease in ankle/brachial index of more than 0.15 compared with the initial postoperative ankle/brachial index or a duplex scan showing a graft or anastomotic stenosis of more than 50% underwent angiography and if necessary, a revision or repeat procedure. Occluded grafts were reopened with thrombectomy or thrombolysis or were replaced with a new graft. RESULTS: Assisted primary cumulative vein graft patency in the intensive group (n = 56) compared with that in the routine surveillance group (n = 50) after 3 years was 78% versus 53% (chi square analysis, 4.51; one degree of freedom; p < 0.05). Secondary patency was 82% versus 56% (chi square analysis, 5.62; one degree of freedom; p < 0.05). Assisted primary cumulative e-polytetrafluoroethylene and composite graft patency after 1 year in the intensive group (n = 23) compared with that of the routine surveillance group (n = 20) was 57% vs 50% (chi square analysis, 2.17; one degree of freedom; p > 0.1). Secondary patency was 67% vs 54% (chi square analysis, 1.85; one degree of freedom; p > 0.1). Revisions were made on 14 patent and 10 thrombosed grafts in the intensive group and on four patent and 15 thrombosed grafts in the routine surveillance group. All except eight were made during the first postoperative year. CONCLUSIONS: Intensive surveillance identified failing vein grafts leading to a significantly higher cumulative assisted primary and secondary patency compared with cumulative assisted primary and secondary patency after routine follow-up examination. The patency of e-polytetrafluoroethylene and composite grafts was not influenced by intensive surveillance.

Aged↗
PubMed1995

Unfractionated heparin and low molecular weight heparin do not inhibit the growth of proliferating human arterial smooth muscle cells in culture.

OBJECTIVES: To clarify the effects of unfractionated heparin (UH) and low molecular weight heparin (LMWH) on proliferating human smooth muscle cells (SMC) compared to growth arrested SMC. DESIGN: A cell culture study where proliferating SMC were exposed to different concentrations of UH and LMWH and the effect on proliferation and collagen secretion was studied. Growth arrested SMC were stimulated with serum and the effect of UH on proliferation was measured. SETTING: Sections of Medical Angiology and Vascular Surgery, Malmö General Hospital, Sweden. MATERIALS: Human SMC were established from arterial tissue obtained at vascular surgery or at organ donation. CHIEF OUTCOME MEASURES: Effects of UH and LMWH on total cellular DNA, 3H-thymidine incorporation and collagen secretion using proliferating and growth arrested human SMC in culture. MAIN RESULTS: In proliferating SMC that had not been growth arrested, 1 and 10 IU/ml UH and LMWH significantly increased total cellular DNA compared to controls while DNA synthesis was not influenced. The higher cellular DNA was probably not a consequence of increased proliferation as DNA synthesis was not affected by UH or LMWH. The increased total cellular DNA could instead be due to reduced cell death. Higher concentrations (10 IU/ml) of UH and LMWH also increased collagen secretion. In control experiments with UH DNA, synthesis was decreased in stimulated human SMC that had been growth arrested previously to heparin exposure. CONCLUSIONS: The effects of UH and LMWH on SMC proliferation will depend on the proliferative state of the SMC. The results might be of relevance for the understanding of the atherosclerotic process and for pharmacologic interventions to prevent restenosis after angioplasty or surgery.

Arteries↗
PubMed1995

Pharmacological prophylaxis against postoperative graft occlusion after peripheral vascular surgery: a world-wide survey.

OBJECTIVES: To define current practice regarding the use of pharmacological prophylaxis to prevent postoperative graft occlusion. DESIGN: Prospective open questionnaire. MATERIALS AND METHODS: Questionnaires regarding this subject were sent to vascular surgeons throughout the world to analyse current practice. RESULTS: 651 questionnaires were returned with a response rate of 62% and form the basis for this report. Data from 100,334 vascular reconstructions were reported in this survey. Prophylaxis against postoperative graft occlusions was common. Treatment periods were usually greater than 1 year. Among carotid surgery patients, 82% received prophylaxis, consisting mainly of low-dose acetysalicylic acid (ASA). In Mid-Europe the use of oral anticoagulation was more common than in other regions (p < 0.001). Among aneurysm surgery patients, 38% received prophylaxis. For infrainguinal bypass, ASA in low dose was the most commonly used agent worldwide. However, oral anticoagulation was more frequent in Mid-Europe, in contrast to South America where the combination of ASA and dipyridamole was most common. Considerable geographical differences regarding patient selection, the frequency of specific procedures and operative techniques existed. CONCLUSIONS: Important world-wide differences exist regarding prophylaxis for postoperative graft occlusion.

Anticoagulants↗
PubMed1995

Effect of dextran and enoxaparin on early ePTFE graft thrombogenicity in sheep.

OBJECTIVES: To evaluate the effect of low molecular weight heparin (LMWH), dextran 70 and their combination on platelet adhesion and fibrinogen uptake in ePTFE grafts in an experimental sheep model. DESIGN: Prospective open study. SETTING: Animal Laboratory of a University Hospital. MATERIALS: Early thrombogenicity of ePTFE grafts was studied after interposition in the two common carotid arteries of 40 adult sheep. The animals received one of four different treatment regimens in a double blind randomised way: enoxaparin and polygeline, saline and dextran 70, enoxaparin and dextran 70 or saline and polygeline (control). The substances were administered i.v. with a total dose of 73 antifactor-Xa U/kg for enoxaparin and 1.0 g/kg for dextran 70. Polygeline and saline were used as placebo substances in equivalent volumes. On one side (random allocation) the carotid blood flow was restricted to 25 ml/min, on the other side it was left unrestricted. CHIEF OUTCOME MEASURES: The following variables were studied: 1) fibrinogen uptake; 2) platelet uptake; 3) early graft patency; 4) blood flow in patient grafts; 5) visible presence of graft thrombus; 6) thrombus weight. MAIN RESULTS: The results verified the importance of adequate blood flow as only 30% of grafts with restricted blood flow in the control group were patent compared with 80% of those with unrestricted blood flow (p = 0.038). Dextran 70, enoxaparin and the combination of the two increased early graft patency (p < 0.05) and reduced thrombus weights (p < 0.05) in grafts with restricted blood flow. The relative number of grafts with thrombus free surface was increased in the unrestricted blood flow situation. CONCLUSIONS: Dextran 70 and enoxaparin appeared to be equally effective in decreasing fibrinogen and platelet uptake in the grafts. Their combination was not significantly more effective although there was a favourable trend.

Animals↗
PubMed1995

Determination of the relative glomerular filtration rate of each kidney in man. Comparison between iohexol CT and 99mTc-DTPA scintigraphy.

Iohexol and 99mTc-DTPA were used in 43 patients to determine the relative glomerular filtration rate (GFR), i.e., the GFR of each kidney in percent of total GFR. The amount of any GFR marker accumulating in Bowman's space, tubuli and renal pelvis within a few minutes after i.v. injection, before any marker had left the kidney via the ureter, was defined as proportional to the GFR of that kidney. The renal accumulation of iohexol was determined by CT using 10 slices of 8-mm thickness 1 to 4 minutes after injection. The renal accumulation of 99mTc-DTPA was determined with a gamma camera within 2 minutes after injection. The correlation coefficient between the two methods was 0.98. Due to the higher radiation dose from CT than from 99mTc-DTPA injection, relative GFR determination with CT should be performed when there is also a diagnostic need to reveal morphology.

Adolescent↗
PubMed1994

Prevention of experimental venous thrombosis in rabbits with low molecular weight heparin, dextran and their combinations, administered before or during induction of venous endothelial trauma.

An in vivo experimental venous thrombosis model based on endothelial damage and flow reduction was used to investigate the effect of low molecular weight heparin (LMWH) alone and in combination with dextran and the effect of surgical and endothelial trauma on thrombus formation, formation of occlusive thrombi and thrombus weights. Five groups with 15 rabbits in each were studied. Two groups received dalteparin (50 anti-Xa IU/kg i.v.) before surgical trauma or after, during the endothelial trauma and two groups received dalteparin (50 anti-Xa IU/kg i.v.) with dextran 70 (1 g/kg i.v.) before surgical trauma or after, during the endothelial trauma. Compared to a control group (saline) all treatment regimes reduced significantly the frequency of thrombosis and occlusive thrombi as well as thrombus weights. No significant difference was observed between the identical treatment groups when the substances were introduced before respective after surgical trauma. It is concluded, from the present study that thromboprophylaxis with LMWH in this particular in vivo model, given before or after surgical trauma is equally effective. Dextran has a certain augmenting thromboprophylactic effect when added to LMWH in this model.

Animals↗
PubMed1994

Deep venous thrombosis and occult malignancy: an epidemiological study.

OBJECTIVE: To determine the risk of subsequent cancer in patients with deep venous thrombosis confirmed by venography. DESIGN: Follow up of all patients who had venography for suspected deep venous thrombosis during 1984-88. Patients were traced through a cancer registry up to 1 January 1991. SUBJECTS: 4399 patients who had phlebography in one hospital. SETTING: General hospital in Malmö, Sweden, serving a population of 230,000. MAIN OUTCOME MEASURE: Number of cancers recorded. RESULTS: 4399 patients had venography for suspected deep venous thrombosis; 604 were known to have a malignancy at the time of venography and were excluded from further analysis. 1383 had deep venous thrombosis, 150 of whom subsequently developed cancer. 182 of the 2412 patients without thrombosis developed cancer. During the first six months after venography 66 patients with thrombosis developed malignancy compared with 37 patients without thrombosis (P < 0.0001). 38 of the cancers in the deep venous thrombosis group were detected by history, physical examination, and laboratory tests. Three patients had postoperative or post-traumatic deep venous thromboses. Only two of the remaining patients would have benefited from early detection by extensive screening. After six months the incidence of cancer was identical in patients with and without thrombosis. CONCLUSION: Deep venous thrombosis is associated with a significantly higher frequency of malignancy during the first six months after diagnosis. Malignancies can be found with simple clinical and diagnostic methods and extensive screening is not required.

Adult↗
PubMed1994

Heparin and protamine use in peripheral vascular surgery: a comparison between surgeons of the Society for Vascular Surgery and the European Society for Vascular Surgery.

It was the intent of this study to document, in general, the patterns and complications of heparin and protamine usage during carotid endarterectomy, aortic and femoral-popliteal-tibial reconstructions for occlusive disease, elective and emergent abdominal aortic aneurysmectomy, thromboembolectomy, and dialysis arteriovenous (AV) fistula placement by surgeons from North America and Europe. All vascular surgeons from the Society for Vascular Surgery (SVS) and the European Society for Vascular Surgery (ESVS) were surveyed by a voluntary, self-reported questionnaire. Six hundred and forty-six completed questionnaires (284 from SVS and 362 from ESVS), representing a 62% response rate, were returned for evaluation. Systemic and regional administration of heparin was common during vascular procedures performed by both SVS and ESVS surgeons. Use of protamine to reverse heparin anticoagulation varied among SVS and ESVS surgeons, respectively, during: carotid endarterectomy (54% vs. 26%, p < 0.01), elective aortic reconstruction for occlusive disease (58% vs. 23%, p < 0.001), elective aortic reconstruction for abdominal aortic aneurysm (63% vs. 27%, p < 0.001), and femoral-popliteal-tibial reconstruction (44% vs. 15%, p < 0.001). Adverse reactions to protamine among the 25,219 and 12,902 cases reported from SVS and ESVS surgeons, respectively, included: hypotension (1209 and 495 cases), pulmonary artery hypertension (65 and eight cases), anaphylaxis (52 and 10 cases), and death (seven and two cases). These adverse responses accounted for 5.3% and 4.0% of the SVS and ESVS cases, respectively. Although this study is subject to the known limitations of a retrospective survey, it is clear that heparin use is common. Protamine reversal of heparin anticoagulation is more common in North America.(ABSTRACT TRUNCATED AT 250 WORDS)

Data Collection↗
PubMed1994

Time-related anticoagulation after regional and systemic administration of heparin in patients undergoing aortoiliac surgery.

Heparin anticoagulation during cardiovascular surgical procedures remains poorly investigated and understood. The objective of this investigation was to assess the effectiveness of three methods of heparin administration. Heparin sulfate (75 IU/kg) administered to patients undergoing aortoiliac surgery was randomised to one of three methods: Group I (n = 9) heparin was injected into a central venous line 5 minutes before infrarenal aortic clamping; Group II (n = 9) heparin was injected into the distal aneurysm immediately after infrarenal aortic clamping; and Group III (n = 8) heparin was injected into a central venous line immediately after infrarenal aortic clamping. Blood samples were analysed for anticoagulant activity from both the upper and lower extremities at 5, 15, 30, 60, and 120 minutes after heparin administration. Anticoagulation, as measured by aPTT, antifactor Xa levels, and ACT, was achieved in all three groups by 5 minutes, but initially with lower heparin activity (measured as antifactor Xa) in the upper extremity (Group II) and lower extremity (Group III), respectively. These differences were also evident in ACT and aPTT determinations. Intravenous heparin administration prior to aortic cross-clamping achieves excellent anticoagulation (anti-factor Xa approximately 1 U/ml) in both upper and lower extremities after 5 minutes. With regional administration, rapid heparin redistribution occurs, but it takes longer to achieve the same level of anticoagulation distant from the site of administration. Nevertheless, from a practical perspective the method of administration does not appear to have a great influence on the eventual achievement of adequate anticoagulation.

Aortic Aneurysm, Abdominal↗
PubMed1994

Protamine neutralization of intravenous and subcutaneous low-molecular-weight heparin (tinzaparin, Logiparin). An experimental investigation in healthy volunteers.

The aim of the present study was to investigate whether tinzaparin sodium (a low-molecular-weight heparin (LMWH)) was fully and permanently neutralized in vivo in man by protamine sulphate (PS) after intravenous (i.v.) or subcutaneous (s.c.) injection. Fifty healthy adults equally divided in five age- and sex-matched groups were included. The groups received 50 IU unfractionated heparin (UH)/kg body weight (b.w.) i.v., 50 anti-factor Xa (anti-Xa) IU tinzaparin/kg b.w. i.v., 75 anti-Xa IU tinzaparin/kg b.w. s.c., 175 anti-Xa IU tinzaparin/kg b.w. s.c., or 1 ml of saline s.c. PS was given as a 10 min infusion in a dose of 1 mg/100 IU of heparin in the four first groups while 0.5 mg PS/kg b.w. was given in the placebo group. In the i.v. groups PS was administered 45 min after the heparin injection, and in the s.c. groups 180 min post-heparin injection. In the UH group PS fully and permanently neutralized all three activities. In the i.v. tinzaparin group PS reversed 80% of the anti-Xa activity, while the anti-IIa and aPTT activities were fully reversed. A slight, but statistically significant, increase in anti-Xa and anti-IIa activities were seen following i.v. tinzaparin. In the s.c. groups 60-65% of the observed peak anti-Xa activity was neutralized, anti-IIa was almost completely reversed, and aPTT returned nearly to baseline values. A gradual return of the anti-Xa activity (65-75%), anti-IIa activity (55%) and aPTT activity (35-45%) was seen in the s.c. groups 3 h after reversal compared with the observed peak values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Effect of low molecular weight heparin, dextran and their combinations on experimental venous thrombosis in rabbits.

An experimental model based on the combination of endothelial damage and flow reduction was used to induce jugular vein thrombosis in rabbits. The effect on thrombosis of a low molecular weight heparin (LMWH [Fragmin]), dextran 70, placebo and their combination was studied in a double-blind fashion with actual doses used in clinical thromboprophylaxis. Saline and polygeline were used as placebo in the control group. Four groups with 120 isolated vein segments in 60 animals were studied for presence of thrombus formation, occlusive thrombi and thrombus weights. Dextran reduced the thrombus weights (p = 0.048) and the formation of occlusive thrombi (p = 0.01), but not the formation of thrombi when compared with the placebo control group. Similarly, LMWH reduced the thrombus weights (p = 0.046), the formation of thrombi (p = 0.007) and occlusive thrombi (p = 0.0001). Compared with the LMWH group the group treated with the combination of LMWH and dextran was found to reduce the frequency of occlusive thrombi (p = 0.03) and numerically, but not significantly, further reduce the overall frequency of thrombosis (p = 0.18) and thrombus weights (p = 0.11). The results are consistent with an augmentation of the antithrombotic effect of LMWH by dextran 70. The need for further evaluation of the combined efficacy of LMWH and dextran is apparent from this study.

Animals↗
PubMed1994

Study of the interaction of dextran and enoxaparin on haemostasis in humans.

The effect on haemostatic variables by dextran 70, enoxaparin and their combinations, given in doses of 500 ml i.v. and 40 mg s.c. respectively, was studied in a randomised cross-over fashion in twelve healthy male volunteers. Antifactor-IIa activity, antifactor-Xa activity, APTT, factor VIII, vWF, bleeding time and blood counts were analysed over a 24-h period. Dextran alone did not affect antifactor-IIa activity and antifactor-Xa activity. No difference in antifactor-IIa and antifactor-Xa activity was found for Amax, tmax, AUC0-8 h and AUC0-24 h in the groups treated with enoxaparin or the combination of enoxaparin and dextran. Only minor changes in APTT were observed without statistical significance between the treatment groups. Factor VIII did not change significantly in the three treatment groups. However, vWF was significantly reduced in the dextran and the dextran/enoxaparin group (p = 0.046 and 0.01 respectively) but no difference was found between the two groups. Bleeding time was not significantly increased four hours after administration of the test substances and no difference was found between the individual treatment groups. Our findings indicate that dextran can be combined with enoxaparin, when used in thromboprophylactic doses, without increased risk for bleeding.

Adult↗
PubMed1994

Fatal pulmonary embolism in an unselected series: the possible role of caval filters in prevention.

OBJECTIVE: To evaluate the possible benefit of inserting a caval filter for the prevention of pulmonary embolism (PE) in an unselected group of patients admitted to hospital. DESIGN: Analysis of clinical data collected prospectively. SETTING: University hospital, Sweden. SUBJECTS: 1391 patients who presented during 1987 435 with deep vein thrombosis (DVT), thrombus in the right atrium or the right ventricle or PE at necropsy; 366 patients shown to have DVT on phlebography; 44 shown to have PE on pulmonary scintigraphy; and 546 patients operated on for hip fractures. OUTCOME MEASURES: Clinical description of patients and groups of patients who died of PE who could possibly have benefitted from insertion of a filter. RESULTS: Of the 435 patients with DVT or PE or both, 141 had DVT in the femoral or iliac veins or in the inferior vena cava together with PE which contributed to the cause of death. Only 11 of these had been suspected clinically of having DVT in or below the inferior vena cava and only 1 of these was less than 80 years old and did not have malignant disease with distant metastases. Of the 366 patients with phlebographically confirmed DVT 8 died with PE that had contributed to the cause of death; 6 had incurable cancer and the remaining two were over 85 years. Of the 44 patients with scintigraphically confirmed PE 2 patients (aged 78 and 89) died of PE that had already been diagnosed clinically and none would have benefited from insertion of a filter after diagnosis. There were 9 PE deaths related to PE among 546 patients operated on for hip fractures, and all but one had potentially lethal coexisting disease or were over 80 years old. CONCLUSION: In this epidemiological survey only a few patients would have benefited from insertion of a caval filter. The results call for a restricted use of caval filters until benefit has been confirmed by prospective studies.

Adolescent↗
PubMed1994

Endothelial cell seeded dacron aortobifurcated grafts: platelet deposition and long-term follow-up.

OBJECTIVE: The prospect of seeding endothelial cells to a prosthetic graft has been successful in the experimental setting, but less convincing in clinical studies in humans. This study was performed with the objective of evaluating endothelial cell seeding of aorto-bi-iliofemoral reconstructions with cells harvested at the same procedure. EXPERIMENTAL DESIGN: Randomized study with one graft limb seeded and with at least 5 year follow-up. SETTING: University Hospital. PATIENTS: 15 patients undergoing aorto-bi-ilio-femoral reconstruction. INTERVENTIONS: One graft limb (randomly determined) was seeded with autologous endothelial cells (median 5.2 x 10(5)) enzymatically (Dispase II) harvested from the saphenous vein (length 8-15 cm, diameter 4-8 mm). The other graft limb served as a control. MEASURES: Two months after surgery platelets were labelled with 111In and platelet activity registered over the graft. Long-term outcome were followed (median 5 years and 10 months). RESULTS: No difference in platelet activity was noted between the seeded and non-seeded graft limb. Different techniques of calculating graft wall activity showed large interindividual variations in the results. Long-term outcome showed that three patients died, two from myocardial infarction on postoperative day three and 60, and one patient died four years after surgery from a lung cancer. Grafts functioned well. In one non-seeded graft limb the patient had severe microembolisation postoperatively that required amputation 10 days after surgery. Of seeded graft limbs one occluded 42 months after surgery, intimal hyperplasia at the distal anastomosis was seen and in one patient progress of arteriosclerosis required additional surgery 12 months after initial operation with profundaplasty (partly due to intimal hyperplasia) and later two additional femoro-distal reconstructions were needed. CONCLUSION: In summary with our single-staged technique for seeding of endothelial cells to a graft limb in a high flow situation no effect on platelet activity at two months was found and long-term outcome was not obviously influenced.

Aged↗
PubMed1994

Antithrombotic effect of recombinant truncated tissue factor pathway inhibitor (TFPI1-161) in experimental venous thrombosis--a comparison with low molecular weight heparin.

The aim was to investigate whether a truncated recombinant Tissue Factor Pathway Inhibitor (TFPI1-161), which lacked the third Kunitz-type domain and the basic c-terminal region, had an antithrombotic effect comparable to LMWH in a randomised double-dummy study. The experimental thrombosis was induced in jugular veins, in a total of 40 rabbits by a combination of destruction of the endothelium and restricted blood flow. Group 1: placebo, gr 2: LMWH 60 anti-FXa IU/kg, gr 3-5: 0.1, 1.0 and 10.0 mg/kg TFPI1-161. TFPI1-161 reduced the thrombus weights in all treated groups, significantly in doses of 1.0 and 10.0 mg/kg compared to placebo. The frequency of thrombosis and occlusive thrombosis were also significantly reduced in those doses. The antithrombotic properties of TFPI1-161 (1.0-10.0 mg/kg) measured as thrombus weight, frequency of thrombosis and frequency of occlusive thrombosis was equivalent to the anti-thrombotic properties of LMWH. In the anti-FXa, APTT and PT-assays TFPI1-161 displayed a dose dependent increase of activity. Recombinant-TFPI1-161 did not influence the anti-FIIa-assay. No haemorrhagic side effects were noted.

Animals↗