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Biomedical subjects

H Magometschnigg

Publications and source records attributed to H Magometschnigg.

At least 19 recordsLinked to original sources
PubMed1996

Stenoses of the first segment of the vertebral artery: difficulties in angiographic diagnosis.

Pathology at the origin of the vertebral artery may be the cause of incapacitating vertebrobasilar insufficiency (VBI). Preoperative diagnosis is made primarily on angiographic criteria. We compared intraoperative and angiographic findings in 30 patients and found important diagnostic discrepancies in patients with a caudal, ventral or dorsal origin of the vertebral artery. In their angiograms, vessel superimposition led us to over look 3 ostial stenoses and 10 stenoses due to kinking. Angiographic assessment of patients with VBI can be difficult. Adequate visualisation of the origin of the vertebral artery is mandatory for accurate diagnosis.

Aged↗
PubMed1994

Treatment of non-healing skin ulcers with autologous activated mononuclear cells.

The aim of this study was to investigate whether cultured autologous mononuclear cells (MNC) effectively initiate, accelerate and improve granulation and epithelialisation of skin ulcers. Thirty-three patients with chronic arterial occlusive disease (CAOD; n = 21) or venous post-thrombotic syndrome (PTS; n = 12) were treated with autologous MNC and compared with a control group of 30 patients who received tissue culture medium alone. Previous treatments had been unsuccessful for a mean of 9.23 (3-19) months. MNC were harvested from the peripheral blood of each patient by standard techniques, cultured for three days and applied to the ulcer twice a week. After 4.6 +/- 1.9 weeks, 29/33 ulcers were closed in the MNC group. Patients in the control group took 8.1 +/- 1.2 weeks for 17/30 ulcers. Thus ulcer healing was significantly speedier with MNC seeding; 48% of all ulcers were closed after 30 days of MNC treatment and 92% after 60 days. Patients with PTS responded significantly faster than patients with CAOD. In 90% of patients with painful ulcers MNC treatment resulted in pain relief, whereas in the control group only 50% of patients became pain-free.

Aged↗
PubMed1994

Changes following in vitro endothelial cell lining of ePTFE prostheses: late morphologic evaluation of six failed grafts.

This paper describes the morphologic appearance during long term follow-up of in vitro endothelialised ePTFE grafts (IVECL) implanted in patients with crural reocclusions. Between June 1989 and December 1990, 13 femorocrural IVECL bypasses were implanted. Follow-up angiograms demonstrated stenoses in the middle of the graft in six patients. Two of these patients developed symptoms, and the grafts were biopsied approximately 1.5 years after implantation during a patchplasty procedure. The remaining four patients with asymptomatic stenoses refused elective reoperation and suffered a graft occlusion 53 to 619 days after implantation, all leading to amputation. Biopsy specimens and explanted grafts were examined with standard and electron microscopy. Both biopsies demonstrated multiple layers of degenerating myofibroblasts (MFB). The four explanted grafts also showed altered MFB in addition to necrosis of the graft surface. No endothelial cells were seen on any of the preparations. Long term follow up of IVECL protheses in the crural position has demonstrated that it is possible to lastingly bind cells on an artificial surface. Whether the MFB found are a substitute of lost endothelial cells, or are an end product of metaplastic and/or degenerative alterations, can only be clarified through further biopsy studies.

Arterial Occlusive Diseases↗
PubMed1994

Intraoperative control following femorodistal revascularization: angioscopy is superior to angiography.

Intraoperative angioscopic control was performed in an early series of 27 patients undergoing peripheral vascular surgery. The majority were complex or re-do operations; reversed saphenous vein and PTFE-grafts were used as bypass material exclusively. Angioscopic findings were compared to conventional angiography with respect to the detection of technical problems leading to further surgical procedures. Angioscopy was feasable in 92.5%, it failed twice due to irrigation problems, which was before we used a dedicated angioscopy roller-pump. In 6 patients relevant findings requiring further surgical manipulations were only detected angioscopically, in 2 patients such findings were detected by angioscopy as well as by angiography. Such findings included technical problems (graft rotation [n = 1], anastomotic narrowing [n = 2]), balloon catheter injuries after thromboembolectomy (n = 2) and residual thrombi after local thrombectomy (n = 3); 5 of these patients had undergone previous vascular procedures in the same operation field. After local correction (n = 5) or placement of a new bypass (n = 3) there was no early graft failure. This early angioscopic experience confirmed previous reports that satisfactory visualization and specific recognition of angiographically unsuspected problems after peripheral reconstructions can be obtained by intraoperative angioscopic control. This was seen very distinctively in more complex and re-do operations, which we see as the cases most needing routine angioscopic control.

Aged↗
PubMed1993

[Effects of carotid endarterectomy on various neuropsychologic parameters. A neuropsychologic longitudinal study].

Carotid endarterectomy was performed in 25 patients with symptomatic cerebrovascular disease. All patients underwent detailed neuropsychological investigations immediately before surgery, immediately after surgery, and again after a follow-up period of 14 months. Immediately after surgery the flicker fusion frequency was temporarily reduced, indicating an impairment of global cognitive functioning. Postoperatively, verbal attention was found to be improved, particularly in younger patients, in patients with TIA, and in patients with left-sided operation. Finally, visual retention (Benton) was improved at the end of the observation period, especially in older patients and in patients with left-sided operation. Considering the complexity of pathologic brain perfusion, the effects of carotid endarterectomy can only be explained if a multidimensional approach is adopted.

Aged↗
PubMed1993

Preoperative assessment and prediction of postoperative results in an artificial arterial network using computer simulation.

A computer model has been developed that can be used to describe the human arterial system mathematically. It simulates the complex relationship of morphology and hydraulics in the vessel network. After entering patient data into a standard vessel model, the mean flow velocity, the flow direction, and the blood pressure at each specified point of the flow network can be calculated. The vessel picture can be altered and modified with the help of a graphic editor. Localized or diffuse stenoses, bypasses with simple or multiple anastomoses, end-to-end anastomoses, end-to-side anastomoses, etc., can be studied in terms of the hydraulic effects on the local situation or on the entire vessel system. Experimental results of ultrasonic mean flow data in vessel systems of leg and cerebral arteries of patients are compared with calculated values. The predicted and measured flow velocities show a mean difference of about 10% indicating that such a computer model may be successfully used in the optimal planning of bypass operations.

Arteries↗
PubMed1993

[Stenoses and occlusions of the abdominal aorta in patients less than 40-years old].

Stenosis or occlusion of the abdominal aorta in patients under 40 years of age is either due to a congenital malformation (abdominal aortic coarctation) or due to idiopathic aortitis (Takayasu's arteritis). Some authors, however, consider abdominal aortic coarctation as a subtype of Takayasu's arteritis. We evaluated 9 of our cases and 108 well-documented cases from the literature to help decide the question whether abdominal aortic coarctation is an entity of its own or a subtype of Takayasu's arteritis. In coarctation there is a slight male predominance, patients are usually younger than 20 years of age, and the short aortic stenosis is suprarenal with involvement of the renal arteries. In Takayasu's arteritis females are predominantly affected, patients are usually over 20 years of age, and the long aortic stenosis or occlusion is infrarenal without involvement of the renal arteries. Abdominal aortic coarctation must therefore be considered as a separate disease. Aortography is important, because the morphology of aortic alterations often allows a radiological diagnosis.

Adult↗
PubMed1993

Use of varicose veins as arterial bypass grafts.

Varicose veins are not generally used as arterial bypass grafts despite their physiological endothelial flow surface. The large, irregular diameter and the thin wall renders these veins inadequate. Experimental studies have shown that a considerable reduction in the diameter of veins can be achieved by external wrapping without the generation of obstructing folds of the vein wall. A Dacron mesh tube surrounding varicose veins was used as a bypass graft in 13 infrainguinal arterial reconstructions. Ligated larger side branches and connections of the mesh segments caused irregularities of the otherwise smooth flow surfaces. Ten grafts were patent after a mean follow-up of 17 months. Two grafts have remained patent despite severe outflow obstruction in one and proximal occlusion in the other; both underwent successful interventions. The antithrombogenic properties of these grafts were partly due to a marked increase of the vasa vasorum. Externally constricted varicose veins may be used as arterial bypass conduits with good intermediate-term patency.

Aged↗
PubMed1993

[Aneurysma spurium after iatrogenic arterial puncture--incidence, risk factors and surgical therapy].

Due to the markedly increased number of arterial punctures performed during diagnostic angiography and angioplasty procedures for cardiac and peripheral vessel disease, the complication of false aneurysms after arterial puncture has gained increasing significance. The incidence of false aneurysms after puncture reported in the literature ranges from 0.05-2%. However, careful sonographic follow-up may reveal an incidence twice as high. The goal of this retrospective investigation of 28 patients with false aneurysms was to elucidate risk factors leading to failure of spontaneous closure of the arterial site, as well as to examine the symptoms and clinical course of such patients. Pseudoaneurysms became manifest, depending on the method of puncture, on average 16.4 days after the procedure. The highest risk was seen in adipose patients (18 pts., 64.3%). In these patients the number of tangential and multiple vessel punctures was also highest. Further risk factors were local vessel sclerosis, hypertension, diabetes mellitus, poor general condition, and disturbances of blood coagulation. The typical clinical findings were seen in only 13 patients. In 3 patients blood loss was the predominant symptom. Twelve further pseudoaneurysms (42.8%) were found incidentally at follow-up. The diagnosis was made in all patients sonographically. In 1 patient it was initially identified as an incidental finding at angiography. In 25 cases simple vessel reconstruction was possible (stitch or patch). In 3 cases (10.7%) a more extensive procedure involving vessel replacement was necessary. Severe postoperative complications included local infection (in 2 patients, 1 of whom also had a recurrent false aneurysm) and arterial bleeding necessitating surgical intervention (1 patient).(ABSTRACT TRUNCATED AT 250 WORDS)

Aneurysm, False↗
PubMed1992

Mesh tube--constricted varicose veins used as bypass grafts for infrainguinal arterial reconstruction.

Varicose veins are generally deemed inappropriate graft material for arterial reconstructions despite their physiologic flow surface because of their large and irregular caliber. Size reduction by threading such veins in constricting tubes may create bypass grafts of suitable caliber as long as redundant wall material does not cause stenoses. Sixteen human varicose veins (mean +/- SD, 13 +/- 3 mm diameter) obtained after stripping operations were inserted into Dacron mesh tubes of 6 mm internal diameter. Paraffin casts of the distended veins showed a size reduction of 6.9 +/- 2.6 mm. Wall material formed folds in only two veins. In both cases, diameter reduction was more than 10 mm. However, the folds did not result in significant stenoses. Mesh-constricted varicose veins were used as bypass material in 11 infrainguinal arterial reconstructions. All externally supported segments showed satisfactory size reduction without stenoses or folds. One graft occluded 2 months after surgery. Two patients had to undergo reoperation after 2 and 16 months, respectively. None of the complications could be attributed to the constriction of veins. The remaining grafts are patent and functional after a mean of 17 months (range, 6 to 42 months). Considerable size reduction by external wrapping of varicose veins is possible without adverse side effects. Such constricted veins were used successfully as bypass grafts for infrainguinal arterial reconstructions.

Aged↗
PubMed1992

The use of mesh-tube-constricted dilated or varicose veins as arterial bypass conduit.

In general, dilated and varicose veins are not used as arterial bypass grafts despite their physiological endothelial lining. A uniform small diameter may be achieved by inserting such veins into mesh tubes. To test the degree to which dilated veins can be constricted without forming folds, in-vitro and experimental investigations were performed before such composites were used for clinical reconstructive surgery. Ovine jugular veins with a diameter of 15 mm were inserted into 6 mm tubes. After casting in paraffin wax none of the specimens showed folds on the flow surface. In 12 sheep pairs of mesh-constricted jugular veins and native femoral veins were implanted as femoropopliteal bypass grafts. Six animals were killed at 6 months and 6 at one year. All bypasses remained patent and none showed signs of obstruction caused by folds or anastomotic hyperplasia at angiographic control. Intimal hyperplasia was significantly reduced from 416 +/- 143 microns in the midportion of native vein grafts to 231 +/- 76 microns (p = 0.0001 paired t-test) in constricted veins as well as at the anastomoses (358 +/- 256 microns vs. 180 +/- 73 microns; p = 0.008). Partially or totally mesh-tube-constricted varicose veins were used for infrainguinal reconstructions in 19 patients and for coronary revascularization in 3. All grafts showed an even calibration at control angiography. As constriction does not lead to internal folds, varicose or dilated veins may be used successfully as bypass grafts after insertion into mesh tubes. The external reinforcement reduces the intimal hyperplasia within the graft and also reduces anastomotic hyperplasia.

Aged↗
PubMed1992

[Noninvasive follow-up by color-coded Doppler sonography after surgical interventions on the extracranial cerebral arteries].

By means of colour-coded Doppler sonography we studied retrospectively the incidence of postoperative changes in 54 patients following 58 carotid endarterectomies. The interval between operation and ultrasound varied from one to 41 months. The overall incidence of recurrent carotid disease was 50% with a 31% (18 of 58) of hemodynamically insignificant restenoses, a 13.8% (8 of 58) incidence of haemodynamically significant restenoses, and a 5.2% (3 of 58) of occlusions. The segment that had been endarterectomized showed a bulbous dilatation in 24.1% (14 of 58). In all of these cases extensive flow reversal zones could be demonstrated, the possible importance of which is discussed. Examinations in 9 patients with reimplantation of subclavian artery to the common carotid artery and grafting technique between these arteries and in 11 patients with reimplantation of vertebral artery to the common carotid artery demonstrated one occlusion of the ipsilateral vertebral artery.

Carotid Artery Thrombosis↗
PubMed1992

Implantation of in vitro endothelialized polytetrafluoroethylene grafts in human beings. A preliminary report.

To assess the impact of in vitro endothelialization on prosthetic graft patency, we performed femorotibial reconstruction in four patients. Polytetrafluoroethylene grafts (6 mm), lined with cultivated autologous endothelial cells, harvested from the veins of the forearm, were used. Autologous endothelial cells were harvested enzymatically and characterized by morphology and factor VII staining. After a cultivation period of 17 to 23 days, the cell count increased from 27 +/- 3 x 10(4) endothelial cells to 5.4 +/- 1.1 x 10(6). Endothelial cell seeding on polytetrafluoroethylene prostheses was then performed. To improve endothelial cell attachment to the graft surface, polytetrafluoroethylene grafts (60 to 70 cm; 6 mm diameter) were precoated with fibrin glue containing fibrin and fibronectin and the fibrinolysis inhibitor aprotinin. Seeding density of 49 +/- 10 x 10(3) endothelial cells per square centimeter yielded a preconfluent monolayer immediately after seeding, as demonstrated by scanning electron microscopy. A second cultivation period of 6 days, after seeding and before implantation, was necessary for establishment of a confluent monolayer and to allow for maturation of the endothelial cell cytoskeleton as well as production and excretion of extracellular matrix. Grafts endothelialized in vitro were implanted in four patients requiring femorotibial reconstruction. Scintigraphic studies with indium 111-labeled platelets demonstrated little or no platelet deposition, indicating persistent endothelialization. All grafts remained patent at 3 months after implantation.

Aged↗
PubMed1992

["Pseudo-dissection" in an abdominal aortic aneurysm].

Sonography of 52 patients with aneurysms of the abdominal aorta revealed in 7 cases hypoechoic crescent-like zone between parietal thrombus and the aortic wall which simulated aortic dissection. Duplex-sonography was performed in all cases and no flow could be detected in this area. In two patients intraoperatively several milliliters of a serous fluid could be aspirated from this zone which confirmed the suggestion of seroma within the parietal thrombus. This observation may be found rather frequently and should not be a reason for immediate surgery.

Aortic Dissection↗
PubMed1992

Prospective clinical study with in vitro endothelial cell lining of expanded polytetrafluoroethylene grafts in crural repeat reconstruction.

A nonrandomized prospective clinical study was undertaken to evaluate the technique and efficacy of in vitro endothelial cell lining of synthetic grafts. Twenty-six patients (10 men and 16 women with a mean age of 68.4 years; range, 49 to 80 years) with end stage chronic peripheral vascular disease requiring reoperation were entered into the study. In 13 patients venous endothelial cells were harvested 4 to 7 weeks before operation, grown to confluency in culture flasks, and seeded onto the inner surface of expanded polytetrafluoroethylene grafts. Thirteen patients received untreated expanded polytetrafluoroethylene grafts and served as a control. A scoring system with use of intraarterial angiography was used to assess disease severity. No statistically significant differences in angiographic score were seen between the two groups, indicating comparable severity of disease. Early secondary graft patency (0 to 30 days) was 92% for the in vitro endothelial cell lining group and 53% for control patients. The amputation rate after 18 months for the in vitro endothelial cell lining group was 15%, with a 31% rate in the control group. The functional performance of the in vitro endothelial cell lining bypasses was superior to that of untreated bypass grafts during the observed follow-up period. These early results suggest that in vitro endothelial cell lining is a method that can reduce the early occlusion rate now seen after repeat reconstruction of crural vessels.

Aged↗
PubMed1991

[Percutaneous transluminal implantation of the Günther cava filter: experience based on 22 patients].

During the last three years, Günther cava filters were implanted in 20/22 patients. The indications for the procedure were single pulmonary emboli in 4, recurrent pulmonary emboli in 6 and pelvic vein thromboses with free thrombus but without pulmonary emboli in 12. In 2 patients implantation of the cava filter could not be carried out because of low position of the renal veins. 15 patients were re-examined 2 weeks to 20 months after the introduction of the filter. In no cases was there clinical evidence of recurrent pulmonary emboli. Occlusion of the inferior vena cava was demonstrated in 1 patient and downward displacement of the cava filter in 6 patients. Perforation of at least one prong of the filter through the wall of the inferior vena cava could be recognized in 4 patients. In 1 patient there was fracture of one leg of the filter but this was clinically not apparent.

Adult↗