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Biomedical subjects

L Norgren

Publications and source records attributed to L Norgren.

At least 55 records · Page 3Linked to original sources
PubMed2000

Endovenous management of saphenous vein reflux. Endovenous Reflux Management Study Group.

PURPOSE: This study assessed clinical outcomes of two catheter-based endovenous procedures to eliminate or greatly mitigate saphenous vein reflux. MATERIALS AND METHODS: A computer-controlled, dedicated generator and two catheter designs were used to treat 210 patients at 16 private clinic and university centers in Europe. The Closure catheter applied resistive heating over long vein lengths to cause maximum wall contraction for permanent obliteration; the Restore catheter induced a short subvalvular constriction to improve the competence of mobile but nonmeeting leaflets. RESULTS: Closure treatment caused acute obliteration in 141 (93%) of 151 limbs; Restore treatment, shrinking one or more valves, acutely reduced reflux to less than 1 second in 41 (60%) of 68 limbs. Closure treatments were associated with early recanalization (6%), paresthesias (thigh, 9%; leg, 51%; P <.001), 3 skin burns, and 3 deep-vein thrombus extensions, with 1 embolism. Restore treatments were thrombogenic (16%) despite prophylactic anticoagulation, and treated valves enlarged over 6 weeks, becoming less competent. Clinical Efficacy Assessment Project clinical class was significantly improved after both treatments, up to 1 year. At 6 months, 87% of 53 Closure patients were class 0 or 1, 75% were symptom-free, and 96% of 55 treated limbs were completely free of reflux. Fourteen of 31 Restore patients (45%) had no symptoms, but 55% were class 2 or lower and only 19% had less than 1-second reflux. CONCLUSION: Closure treatment is clinically effective, albeit with offsetting complications and early failures; these are being addressed through four procedural modifications. Restore valve shrinking, although conceptually attractive, is too problematic to be competitive with Closure treatment or saphenectomy.

Catheterization, Peripheral↗
PubMed2000

First-generation aortic endografts: analysis of explanted Stentor devices from the EUROSTAR Registry.

PURPOSE: To examine the structure and healing characteristics of chronically implanted Stentor endografts that were explanted due to migration, endoleak, thrombosis, or aneurysm expansion. METHODS: The devices were harvested following reoperation (n = 5) or autopsy (n = 1) with implantation times ranging from 13 to 53 months. Structural modifications to the metal components were examined using radiography, endoscopy, and magnetic resonance imaging (MRI). Specimens taken from components of the modular stent-grafts were examined histologically and with scanning electron microscopy (SEM) to assess healing behavior. Physical and chemical stability of the nitinol wires and woven polyester graft material was evaluated using SEM and electron spectroscopy for chemical analysis. RESULTS: Although the endografts were retrieved for a variety of reasons, they exhibited similar healing and structural modifications. The woven polyester sleeve showed evidence of yarn shifting and distortion, yarn damage, and filament breakage leading to the formation of openings in the fabric. The luminal surface endografts showed incomplete healing characterized by a poorly organized, nonadherent thrombotic matrix of variable thickness. Radiographic and endoscopic observations indicated that structural failure of the grafts, particularly in the main aortic component, was related to severe compaction and dislocation of the metallic frame due to suture breaks. Corrosion marks were observed on some nitinol wires in all devices. Chemical analysis and ion bombardment of the nitinol wires revealed that the surface concentrations of titanium and nickel were not homogenous. The first layer was composed of carbon or organic elements, followed by a stratum of highly oxidized titanium with a low nickel concentration; the titanium-nickel alloy lay beneath these layers. CONCLUSIONS: Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.

Aged↗
PubMed1999

Relationship of femorodistal bypass patency to clinical outcome. Iloprost Bypass International Study Group.

OBJECTIVE: To investigate the relationship between bypass patency, limb survival and clinical symptoms after femorodistal bypass procedures. DESIGN: Multicentre, prospectively planned 12-month postoperative follow-up. PATIENTS AND METHODS: Five hundred and seventeen patients undergoing femorodistal bypass surgery for severe ischaemia. Clinical symptoms, bypass patency were recorded at regular intervals up to 12 months postoperatively. RESULTS: Complete follow-up data was obtained on 498 patients (96%). Fifty-six (17%) of the 341 patients with patent bypasses had either rest pain or ulcers or had undergone major amputation at 12 months. Of the 167 patients with an occluded bypass, 22 patients (13%) had improved clinical symptoms and a total of 59 patients (35%) had avoided major amputation at 12 months. The clinical outcome for patients classified preoperatively as Fontaine stage IV was significantly worse than for those in stage III preoperatively despite similar bypass patency rates. CONCLUSIONS: There is a fair correlation between technical and clinical outcome after femorodistal bypass surgery at 12 months, but there are significant numbers of patients with occluded bypasses who have a good clinical outcome and of patients with patent bypasses who have a poor clinical outcome. The reporting of symptoms in addition to bypass patency would aid the interpretation of surgical results.

Adult↗
PubMed1999

Diabetes mellitus as a risk factor for early outcome after carotid endarterectomy--a population-based study.

BACKGROUND AND PURPOSE: to determine if diabetes mellitus is a risk factor for outcome after carotid endarterectomy (CEA). METHODS: the outcome and complications of all vascular procedures performed in Sweden are registered prospectively in the Swedish Vascular Registry (Swedvasc) and form the basis of this report. During the 10-year period 1987-96 2622 CEAs were analysed for notified complications. RESULTS: of the 2622 CEAs, 341 (13%) were performed on diabetics and 2281 (87%) on non-diabetics. Patients with diabetes presented at a younger age (67.1+/-8.3 years vs. 68.2+/-8.3 years p =0.028), were more likely to have a history of hypertension (61.9% vs. 50% p =0.001) and were less often smokers (34.9% vs. 43.2% p =0.001). Diabetics presented more often with minor stroke (41.3% vs. 30.8% p =0.002) and non-diabetics more often with amaurosis fugax (18.9% vs. 14.4% p =0.04). Diabetics had a higher 30-day mortality (3.2% vs. 1. 4% p =0.02). The 30-day neurologic and cardiac morbidity did not differ. The 1-year mortality was 7.9% in diabetics and 4.4% in non-diabetics (p =0.008). Non-diabetics operated on in 1992-96 compared to those operated on in 1987-91 had a significantly lower combined permanent stroke and death rate (3.7% vs. 5.7% p =0.05), a difference not found in diabetics (6.3% for 1987-92 and 6.8% for 1992-96; N.S). CONCLUSIONS: diabetics had both a higher 30-day and 1-year mortality after CEA compared to non-diabetics, mainly because of cardiac complications. However, postoperative neurologic morbidity did not differ.

Aged↗
PubMed1999

Chronic venous disorders of the leg: epidemiology, outcomes, diagnosis and management. Summary of an evidence-based report of the VEINES task force. Venous Insufficiency Epidemiologic and Economic Studies.

BACKGROUND: To critically review the classification, epidemiology, outcomes, diagnosis and treatment of chronic venous disorders of the leg (CVDL), to issue evidence-based recommendations, and to identify areas requiring further research. METHODS: Articles identified by an extensive literature search were scored by members of an international task force. Only those articles with a moderate or strong rating for internal validity were retained. RESULTS: A scoring system weighing CVDL severity according to the probability of ulcer occurrence is proposed. Epidemiological data on the frequency of CVDL and its risk factors are reviewed. The following items are evaluated: costs associated with treatment; clinical outcomes related to CVDL and its treatment; available generic and disease-specific measures of quality of life; diagnostic procedures used to detect venous reflux; and efficacy of available treatments. CONCLUSIONS: CVDL is an important public health problem, based on its prevalence, cost and impact on quality of life. High-priority areas for research on CVDL are identified.

Chronic Disease↗
PubMed1999

Percutaneous transluminal angioplasty with or without stenting for femoropopliteal occlusions? A randomized controlled study.

BACKGROUND: To investigate the-one year outcome of PTA and stenting and PTA alone for femoropopliteal occlusions. DESIGN: Randomized prospective study METHODS: 32 patients with femoropopliteal occlusions were randomized into two treatment groups: PTA and Strecker-stent (n=15) and PTA alone (n=17). The median age of the patients was 71 years. All patients had chronic limb ischaemia, 66% had tissue loss, 19% had rest pain and 15% had disabling claudication. The median ABPI was 0.45. The occlusion was confined to the superficial femoral artery in 30 cases and to the popliteal artery in 2 cases. The median length of the occlusions was 7.3 cm. Aspirin (ASA), 160 mg daily, was administrated postoperatively but no anticoagulation was used. The follow-up included: clinical examination, measurement of ABPI and control angiography at 12 months or earlier when necessary (20 patients). RESULTS: There was no mortality or limb loss as a consequence of the treatment. There were six (16%) immediate major complications in five patients. In the PTA group, one patient had a myocardial infarction and three patients needed arteriography due to bleeding. In the stent group, one patient required arteriography and embolectomy. The one-year mortality was 6% and there were no amputations. Four patients (two in each group) were operated on with a femorodistal bypass. The rate of clinical improvement was 71% after PTA and stent and 60% after PTA alone (p=0.17). An increased ABPI (>0.10) was shown in 50% of the stent group and 61% in the PTA group (p=0.17). Angiographic re-occlusions were seen in 33% and 75% in the stent and PTA groups respectively (p=0.17), while the rate of restenosis was significantly higher in the stent group (50% vs 25%) (p=0.033). CONCLUSIONS: Stenting following PTA for femoropopliteal occlusions does not significantly improve neither the clinical state nor the clinical/angiographic patency. The results do not justify any routine placement of stent following PTA in the successfully recanalized femoropopliteal arteries. The low rate of acceptance of a follow-up angiography indicates that this kind of study should preferably use duplex scanning instead of angiography for follow-up.

Aged↗
PubMed1998

[Significant regional differences in the frequency of vascular surgery].

The six health care regions of Sweden were compared with regard to the frequency of vascular surgery for three diagnoses: chronic lower extremity ischaemia, abdominal aorta aneurysm, and carotid stenosis. In 1995, the frequency of intervention for chronic lower extremity ischaemia varied from 26/100,000 of the population in northern Sweden to 68/100,000 in the southern region, the variation being greater for critical limb ischaemia than for intermittent claudication. In the country as a whole, the frequency of abdominal aorta aneurysm surgery increased five-fold from 1987-89 to 1993-95. During 1995, regional figures varied from 4.7 to 8.4 per 100,000 for elective procedures, and from 3.8 to 5.5 per 100,000 for emergency procedures. Overall surgical mortality varied regionally, and emergency surgery mortality differed between regional and county hospitals. Carotid surgery manifested the greatest regional difference in frequency, which was 7-fold greater in the southern than in the northern region, while its overall mean frequency was 6/100,000.

Aortic Aneurysm, Abdominal↗
PubMed1998

[Endovascular technique in aortic aneurysm. A promising alternative to open surgery].

The article consists in a presentation of endovascular surgery for abdominal aortic aneurysm repair in 23 cases. Two cases required conversion to open surgery, but the procedure could be completed in the remaining 21 cases, with a current duration of follow-up of up to 30 months. There was early leakage in one case, and late leakage in five cases. Late conversion has been necessary in three instances, and supplementary endovascular measures have been required in a further two instances. All complications have occurred in those cases operated during the first half of the study period. Modification of the endoprosthesis used and increasing skill have reduced both operation time and the complication rate. Intensive care is no longer required, and the median duration of hospitalisation is three days. Follow-up with magnetic resonance imaging has yielded new and important information.

Aged↗
PubMed1998

Adverse reactions during endovascular treatment of aortic aneurysms may be triggered by interleukin 6 release from the thrombotic content.

PURPOSE: It has been shown that endovascular aortic aneurysm repair might induce a significant inflammatory response, mainly involving tumor necrosis factor (TNF-alpha) release. This study determined in vitro whether these inflammatory responses could depend on white blood cell (WBC) activation caused by the aneurysmal mural thrombus. METHODS: Mural thrombus specimens obtained from 10 different aortic aneurysms were weighed, homogenized, and assayed for interleukin 1beta (IL-1beta), interleukin 6 (IL-6), TNF-alpha, and soluble TNF receptor (sTNFRI). RESULTS: Only high amounts of IL-6 (mean, 2973 pg/mL) were found. In contrast, after the addition of healthy donor WBCs to the thrombus mass supernatants, elevated levels of TNF-alpha (mean, 523 pg/mL) were seen. Theoretically, WBCs were stimulated by IL-6, resulting in TNF-alpha release. In additional experiments, it was proven that stimulated WBCs, induced by thrombus mass supernatants, synthesize TNF-alpha (mean, 796 pg/mL), and monoclonal antibodies against IL-6, prevented such TNF-alpha production (mean, 62 pg/mL). CONCLUSION: The biologic responses during endovascular repair may be explained by a release of IL-6 from the aneurysmal thrombus, causing WBC stimulation and production of TNF-alpha. More complex processes cannot be excluded, but the present findings suggest that restrictions of manipulations within the aneurysm may be advisable.

Aortic Aneurysm, Abdominal↗
PubMed1998

Outcome and influence of age after infrainguinal revascularisation in critical limb ischaemia. The Swedish Vascular Registry.

OBJECTIVES: To evaluate whether revascularisation has any influence on the mortality rate, and the impact of old age in patients with critical limb ischaemia (CLI). DESIGN: Analysis of Swedish Vascular Registry (Swedvasc) data. PATIENTS AND METHODS: During 1987-1995, 3730 surgical and 1199 endovascular (PTA) procedures below the groin due to CLI were reported. At 1 year three groups were defined: "occluded, amputated"; "occluded, not amputated" and "patent". Survival was also calculated. Clinical outcome at 1 month and at 1 year was defined as: patient "alive, improved", "alive, not improved", "alive, amputated" and "dead". Two age groups < or = 75 years or and > or = 76 years were compared. RESULTS: The mortality rate for the whole group was 5.3% at 1 month and 22.9% at 1 year, with no difference between the Surgery and PTA groups. Significantly more patients were alive and improved after surgery than after PTA at 1 month (82.3% vs. 77.7%) and at 1 year (49.6% vs. 44.3%). The amputation rate was 5.6% at 1 month and 14.4% at 1 year; 17% for diabetics. After surgery, the cumulative mortality rate did not differ between patients with a salvaged limb, irrespectively of patency of the re-construction, but was significantly higher after amputation. After PTA, only a reconstruction reported as patent was linked to the most favourable survival rate. The older patient group had a mortality rate of 6.4% at 1 month and 26.4% at 1 year, significantly higher than the younger group (3.8% and 17.6%, respectively). The amputation rate did not differ according to age. Significantly more patients were alive but not improved in the older group. CONCLUSIONS: The outcome of surgery vs. PTA was similar regarding survival and amputation, but surgery resulted in a greater improvement although this might be due to selection. Older patients and those with an amputation had higher mortality rates.

Age Factors↗
PubMed1998

Magnetic resonance imaging and MR angiography of endoluminally treated abdominal aortic aneurysms.

OBJECTIVES: To evaluate magnetic resonance imaging (MRI) with gadolinium-based contrast medium-enhanced MR angiography (MRA) for the follow-up of endoluminally treated abdominal aortic aneurysms. DESIGN: MRI/MRA, angiography and computed tomography (CT) were performed 1 month after endoluminal stent-graft placement. MRI/MRA was repeated at 6 and 12 months and angiography and CT were added to confirm unexpected findings. MATERIALS: Fifteen male patients with endoluminally treated abdominal aortic aneurysms. METHODS: MRI with MRA, spiral CT with transverse images and angiography were performed. RESULTS: MRI/MRA demonstrated changes of stent-graft morphology, aortic neck- and aneurysmal diameter, stent-graft blood flow, stent-graft leakage, blood flow in lumbar arteries, intra-aneurysmal thrombus, periaortic inflammation and vertebral body infarction. For most of these features MRI/MRA provided more information than angiography and/or CT. MRI was the only method demonstrating thrombus reorganisation and vertebral body infarction. CONCLUSIONS: MRI with MRA provides the relevant information needed for follow-up of endoluminally treated abdominal aortic aneurysms (AAA). This may be the method of choice because of its use of contrast media with very low nephrotoxicity, lack of ionising radiation and non-invasiveness.

Aged↗
PubMed1998

Aortoenteric fistula caused by a ruptured stent-graft: a case report.

PURPOSE: To report a case of aortoenteric fistula secondary to endovascular abdominal aortic aneurysm (AAA) exclusion using the Stentor bifurcated endovascular graft. METHODS AND RESULTS: Seventeen months after a successful endovascular AAA procedure, a male patient developed upper gastrointestinal bleeding. An aortoenteric fistula was diagnosed. At operation, the endograft fabric was found to be ruptured in an area of suture disruption between the nitinol stents. Coincidentally, a pre-existing inflammatory process might have caused adhesions between the bowel and the aortic wall, predisposing to fistula formation. The patient recovered after placement of a conventional aortic graft. CONCLUSIONS: Suture disruption between the internal support stents is a recognized complication in the first-generation Stentor device. Although the case described here is probably not typical of the consequences of this sequela, it does reinforce the need for continual periodic imaging to check for signs of graft disruption in Stentor endografts.

Aged↗
PubMed1998

Prevention of deep vein thrombosis in knee arthroplasty. Preliminary results from a randomized controlled study of low molecular weight heparin vs foot pump compression.

BACKGROUND: We evaluated in a randomized controlled study the possibility to use foot pump mechanical compression compared to routine LMWH as prophylaxis against deep vein thrombosis during knee arthroplasty. METHODS: Forty patients were included in this preliminary report. Eleven patients withdrew, usually during the early phase of the study. RESULTS: Among the 29 patients completing a venography, 27% in the compression group and none in the LMWH group had a DVT. This difference was statistically significant (p<0.05). One further patient in the compression group died from pulmonary embolism 17 days postoperatively. CONCLUSIONS: With the present study protocol, mechanical foot pump compression failed to be as efficient as LMWH prophylaxis.

Aged↗
PubMed1997

Tumor necrosis factor-alpha and interleukin-6 release from white blood cells induced by different graft materials in vitro are affected by pentoxifylline and iloprost.

Inflammatory mediators such as cytokines produced by white blood cells (WBCs) at the site of implantation are important for the biocompatibility of vascular grafts. The aim of the present study was to demonstrate the tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release from WBCs incubated with expanded polytetrafluoroethylene (ePTFE) or woven Dacron grafts. In a second series the effects of pentoxifylline (PTX) and iloprost (ILO), both known to inhibit white blood cell function, on this release were determined. Woven Dacron grafts induced significantly higher release of both TNF-alpha and IL-6 compared to ePTFE. TNF-alpha was detectable first after 2 h, whereas IL-6 was seen after 4 h. Maximum values were reached at 6 and 12 h, respectively. The addition of an endotoxin gave more pronounced patterns of cytokine release not influenced by time. Preincubation with both PTX and ILO at final concentrations of 100 and 10 micrograms/mL, respectively, reduced significantly the TNF-alpha release without differences between the two graft materials, whereas the effect on the IL-6 release varied and was graft material-dependent. In conclusion, graft material-dependent induction of TNF-alpha and IL-6 from WBCs was demonstrated. PTX and ILO influenced the cytokine release. It might be suggested that graft material-induced cytokine production could contribute to intimal hyperplasia in vivo. The present findings encourage further studies regarding graft material-induced WBC alterations and the role of pharmacologic agents influencing this function.

Biocompatible Materials↗