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Biomedical subjects

E Ribbe

Publications and source records attributed to E Ribbe.

At least 19 recordsLinked to original sources

Outcome of treatment of ruptured abdominal aortic aneurysms depending on the type of hospital.

OBJECTIVE: To compare the outcome of patients operated on acutely for ruptured abdominal aortic aneurysms (AAA) or otherwise symptomatic aortic aneurysms in a university hospital and in two county hospitals by the same group of vascular surgeons. DESIGN: Retrospective study. SETTING: 1 university and 2 county hospitals, Sweden. SUBJECTS: 108 patients operated on urgently for AAA, 81 at the university hospital, and 27 at the county hospitals between January 1992 and December 1998. INTERVENTION: Repair of the AAA. MAIN OUTCOME MEASURES: Morbidity and mortality. RESULTS: 21 of the 81 patients having urgent repair of an AAA at the university hospital (26%) had been transferred from the county hospitals. Thirteen patients were not operated on, 7 because of their poor general condition and great age (median 84 years), 3 who refused operation, and 3 in whom the diagnosis was incorrect. During the same time period a further 27 haemodynamically unstable patients were operated on by the same vascular surgeons at the county hospitals. The on-table mortality for patients with ruptured AAA and shock was 5/43 (12%) at the university hospital and 4/27 (15%) at the county hospitals. The corresponding in-hospital rates were 11/43 (26%) and 11/27 (41%). Mortality was significantly higher if the operation was delayed by more than 45 minutes. The incidence of postoperative complications was the same in both hospitals. CONCLUSION: If a patient with a ruptured AAA and shock is admitted to the county hospital and operated on by a specialist vascular surgeon the outcome is fully acceptable. The difference seems to be related to the postoperative period. To what extent the delay caused by the surgeon's journey to the county hospital has any influence on the outcome is not possible to evaluate.

Adult↗

Evidence of calcium phosphate depositions in stenotic arteriovenous fistulas.

This study investigates vascular samples from patients with and without end-stage renal disease (ESRD) to determine the occurrence of calcium depositions. Findings in stenotic arteriovenous (AV)-fistula veins were compared with those of nonstenotic AV-fistula veins, non-AV-fistula veins, and atherosclerotic vessels. Calcium and phosphorus content was measured by means of scanning electron microscopy and its built-in method of energy-dispersive spectrometry (EDS) X-ray analysis. We found calcium and phosphorus in samples from AV fistulas with stenotic areas with a calcium/phosphorus molar ratio of 1. Based on EDS analysis and crystal shape comparison, we conclude that calcium phosphate precipitations in stenotic AV fistulas are brushites with the composition CaHPO(4)*2H(2)O. This specific calcium phosphate deposition was found solely in stenotic AV fistulas, not in nonstenotic AV-fistula veins or non-AV-fistula veins regardless of whether the patient had ESRD. Moreover, this calcium phosphate deposition was different from calcium compounds found in atherosclerotic samples. Whether the precipitation of brushite is primarily involved in the development of vascular-access stenosis or represents a secondary consequence cannot be determined from the present study.

Adult↗

Percutaneous transluminal angioplasty of crural arteries: diabetes and other factors influencing outcome.

OBJECTIVE: to evaluate the efficacy of percutaneous transluminal angioplasty (PTA) of the crural arteries. PATIENTS AND METHODS: a retrospective review of patients treated with PTA of at least one crural artery during an 8-year period (1990--1997). RESULTS: one hundred and fifty-five legs in 140 consecutive patients (mean age 74 years, range 38--91 years) were treated. In 76% a more proximal lesion was also treated. After 1 year, results were significantly better in non-diabetics (improvement rate of 66% vs 32%p <0.05). The outcome for patients with a combination of diabetes, heart disease and renal disease was significantly worse compared to all other patients with an improvement rate of only 9% after 1 year. Patients alive and not amputated at 1 year were significantly more common (p <0.05) among non-diabetics (90%), compared to diabetics (66%). The 1-year mortality for the whole group was 15%, significantly higher for diabetic patients (p =0.04). CONCLUSION: PTA of crural arteries produces reasonably good results in non-diabetic patients. Diabetic patients were doing worse than non-diabetics after a year, though 1-month results were not significantly different. Patients with diabetes, heart disease and renal disease make a high-risk group that has a significantly worse outcome.

Adult↗

Intraoperative contamination of synthetic vascular grafts. Effect of glove change before graft implantation. A prospective randomised study.

OBJECTIVES: to investigate the incidence of intraoperative graft contamination, bacterial species and the influence of change of surgeon's gloves on contamination. DESIGN: a prospective randomised study. MATERIALS AND METHODS: forty patients had implantation of synthetic vascular grafts. All patients received intraoperative cloxacillin (2.0 g) or clindamycin (0.6 g) intravenously. The procedures were randomised to two groups: Group 1 - surgeons changed the gloves before the first contact with the vascular prosthesis and Group 2 - operation without glove change. The growth of all bacterial species from graft segments and from the gloves was recorded. The susceptibility to antibiotics was tested. RESULTS: the number of contaminated grafts was similar in the two groups. Growth of bacteria was recorded from 92.5% (37/40) of the graft segments and 33% (51/156) of glove imprints. Of the cultured species, 75% and 47%, respectively, were identified as coagulase-negative staphylococci (CNS). Twenty-eight per cent of CNS were resistant to cloxacillin, 15% to clindamycin, and 10% to cloxacillin and clindamycin. In all, 25% of the CNS strains were resistant to the prophylactic antibiotic used. In 50% of cases, the antibiogram of the CNS strain recovered from gloves agreed with that of the strain harvested from the graft. CONCLUSIONS: a high incidence of graft contamination was found which was not reduced by changing gloves. However, changing gloves did seem to reduce the number of bacterial species.

Aged↗

Exposure of plasma proteins on Dacron and ePTFE vascular graft material in a perfusion model.

OBJECTIVES: to compare the exposure of plasma proteins adsorbed onto three vascular graft materials (polytetrafluoroethylene ePTFE and two modifications of polyethyleneterephthalate Dacron). METHODS: surface exposure of fibronectin, vitronectin, thrombospondin, antithrombin III, IgG, high molecular-weight kininogen, fibrinogen, albumin and plasminogen was studied by incubation with radiolabelled antibodies in a perfusion model. Perfusion times with human plasma were 1, 4, 24 and 48 hours. RESULTS: all proteins could be detected at 1, 4, 24 and 48 hours after the start of perfusion. Overall, the least amount of proteins adsorbed onto ePTFE. CONCLUSIONS: the low adsorption of proteins onto ePTFE may be one of the reasons for the lower incidence of infections reported with this material.

Adsorption↗

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↗

[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↗

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↗

Secondary aortoenteric fistulae--changes from 1973 to 1993.

AIM: To investigate a series of patients with secondary aortoenteric fistulas and compare it with a previous series (1985-93 vs. 1973-84). DESIGN: Retrospective study of medical records. SETTING: Sixteen vascular surgical centers in Sweden. PATIENTS: Twenty-seven patients were identified making an overall incidence of 0.5% of all aortoiliac operations. Among aneurysm patients the incidence was significantly lower than in the previous series. One patient record could not be identified. Fourteen primary operations were for aortic aneurysm, 12 for occlusive disease and one was an aortorenal vein bypass. RESULTS: Symptoms of the fistula occurred after a median interval of 90 months which is significantly later than the previous series (32 months; p<0.05). The commonest presentation was bleeding followed by septis. The median diagnostic delay was 10.5 days, which was significantly shorter than in the previous series. Most fistulas involved the duodenum (88%). One patient died before surgery. The postoperative mortality was 28%, significantly lower than in the previous series (58%) (p<0.05). At the end of follow up (median 43 months) significantly more patients were alive than in the previous series (42% vs 18%) (p<0.05). CONCLUSION: Over a 21 year period there seems to have been a decrease in the frequency of secondary aortoenteric fistulas after aneurysm surgery, a longer interval before they occur, a shorter diagnostic delay, and a better survival.

Aorta, Abdominal↗

Biological responses differ considerably between endovascular and conventional aortic aneurysm surgery.

OBJECTIVES: To determine the inflammatory responses in endovascular abdominal aortic aneurysm (AAA) repair and their relation to clinical findings. DESIGN: Prospective non-randomised study. SETTING: University Hospital, Department of Surgery. PATIENTS AND METHODS: Seven patients treated with an endoluminal procedure (AAA-E) and seven patients undergoing conventional surgery (AAA-C) were included. Inflammatory parameters were assessed by measurements of the cytokines interleukin (IL)-1 beta, IL-6, IL-8 and Tumour Necrosis Factor-alpha (TNF-alpha); analyses of complement proteins C1q, C4, C3, C5a and Terminal Complement Complexes (TCC); haematologic parameters and determination of C-reactive protein (CRP). RESULTS: In six of seven patients in the AAA-E group blood pressure decreases were recorded during introduction of the device. IL-6 and CRP levels were found to be significantly higher in AAA-C patients compared to the AAA-E group. On the other hand, high TNF-alpha levels were recorded in the AAA-E group. Less consumption of the complement proteins C1q, C4 and C3 was observed in AAA-E compared to AAA-C patients. Increased C5a levels were recorded in the AAA-C group, whereas only slight fluctuations were noticed in the AAA-E group. TCC levels were unchanged in both groups. CONCLUSION: Endovascular aortic aneurysm repair induced a significant inflammatory response, mainly involving TNF-alpha and differing from the findings during open AAA repair. These inflammatory responses were probably related to blood pressure decreases during the procedures. On the other hand, conventional repair induced responses related to the more extensive surgical trauma and reperfusion injury.

Aged↗

Endothelialization of anastomoses in the aorta and inferior vena cava of the rat.

Denuding endothelial damage at anastomoses may lead to thrombotic complications and failure of microvascular reconstructions. Confluent endothelial healing at anastomoses may reduce thrombotic and other complications. The progress of endothelial coverage of anastomotic structures in the aorta and inferior vena cava (IVC) of the rat was evaluated at 3, 5, 8, 11, and 14 days after completion of the anastomoses, by means of scanning electron microscopy. Arterial anastomotic patency was 100%; venous patency was 84%. It was found that endothelial healing progressed towards thin confluent coverage first, thereafter thickening. Coverage was first achieved at the needle defect, then the anastomotic junction, and lastly the suture. The same stage of endothelial coverage of anastomotic structures was reached 5 to 8 days sooner at the IVC anastomosis than in the aorta.

Anastomosis, Surgical↗

Early development of suture holding capacity in vascular anastomoses in the rat.

Early development of suture holding capacity (SHC) of end-to-end anastomoses in the infrarenal aorta and inferior vena cava (IVC) of the rat was studied by measuring the resistance to tensile forces at 0, 3, 5, 8, 11, or 14 days postoperatively. Comparable anastomoses were histologically evaluated. The SHC of the aortic wall decreased following anastomoses and did not regain the strength of nonanastomosed vessels during the first two weeks. The SHC of the IVC also decreased following anastomoses, but regained the strength of nonanastomosed vessels by the 5th day. The relative ultimate strain of the arterial and venous perianastomotic walls decreased slightly, while the relative compliance increased in the aorta and decreased in the IVC. Perianastomotic media necrosis was found exclusively in the arteries. The reduced perianastomotic SHC in the aorta indicates impaired healing, compared to the IVC. Changes in biomechanical properties of the aortic wall following anastomosis may increase its susceptibility to anastomotic complications such as pseudoaneurysms.

Anastomosis, Surgical↗

Reduced susceptibility of polytetrafluoroethylene vascular prostheses to colonization by Staphylococcus aureus following in situ endothelialization.

The impact of endothelialization of polytetrafluoroethylene (PTFE) grafts on susceptibility to experimental colonization by Staphylococcus aureus was studied in a rat model. One hundred and eight grafts (2 mm inner diameter, 5 mm length) were implanted into the infrarenal aorta (54 rats) or the infrarenal caval vein (54 rats). The progress of endothelialization following graft implantation was evaluated by SEM at 1, 3, 7, and 14 days on 6 grafts from each group. We found that the endothelialization was more rapid in caval vein than in aorta: The caval vein grafts were completely endothelialized 2 weeks following implantation compared with endothelialization of approximately 0.5 mm of aorta grafts, measured from each anastomosis. During this time, the resistance to standardized intravenous challenge with 10(8) colony-forming units of S. aureus increased gradually in both groups, and all caval vein grafts tested at 2 weeks were sterile. However, all aorta grafts challenged at 2 weeks were colonized, although to a somewhat lower degree than at earlier challenge. Resistance of PTFE grafts to colonization with S. aureus thus correlated to the degree of endothelialization.

Animals↗

Bacterial adherence to synthetic vascular prostheses and influence of human plasma. An in vitro study.

The in vitro adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli to five commercially available prosthetic vascular graft materials was compared. The influence of precoating the segments with human plasma for 2 h was also studied. S35-methionine was used to radiolabel bacteria. The segments were exposed to bacterial suspensions of approximately 10(7) CFU/ml at 37 degrees C for 0.5-18h. Following repeated washing in phosphate buffered saline (PBS), radioactivity associated with the segments was measured. The adherence of the three clinically relevant bacterial species was higher to untreated Dacron than to gelatin or collagen impregnated/coated Dacron or to PTFE. Furthermore, precoating of grafts with human plasma reduced bacterial adherence to woven Dacron, had a little effect on gelatin coated Dacron, but increased the adherence to collagen treated Dacron and, in particular, to PTFE.

Bacterial Adhesion↗

Influence of some plasma proteins on in vitro bacterial adherence to PTFE and Dacron vascular prostheses.

The in vitro adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli (one strain of each species) to commercially available, microporous polytetrafluoroethylene (PTFE) and woven Dacron vascular grafts before and after coating with human plasma was compared. Standard size segments of the materials were incubated with 35S-labeled bacteria for 0.5-18 h and, following washes, the radioactivity associated with the segment was measured. The binding of each of the tested species to native Dacron was higher than to PTFE. After coating with human plasma, however, the binding of all three species to PTFE was significantly enhanced, whereas the binding to Dacron was reduced. In addition, the influence of coating with serum albumin (HSA), immunoglobulin G (IgG), fibrinogen (Fg) or fibronectin (Fn) rather than whole plasma was tested. We found that coating with HSA reduced the binding of all three species to Dacron and of staphylococci to PTFE. IgG decreased the binding of S. epidermidis and E. coli to Dacron and of S. epidermidis to PTFE. In contrast, Fg enhanced the binding of S. aureus both to Dacron and PTFE, and that of E. coli to PTFE, but decreased the binding of S. epidermidis and E. coli to Dacron. Fn enhanced the binding of S. aureus to Dacron, and of E. coli to PTFE, but decreased the binding of S. aureus to PTFE and of S. epidermidis both to PTFE and Dacron. Thus, both whole plasma and some isolated plasma proteins were found to modulate bacterial adherence to two tested graft materials. From a clinical point of view, bacterial binding to plasma-coated rather than native materials may more adequately determine the likelihood of in vivo colonization of the various materials. Furthermore, precoating of materials with selected proteins may be of value in the prevention of graft colonization.

Bacterial Adhesion↗