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K Schürmann

Publications and source records attributed to K Schürmann.

At least 19 recordsLinked to original sources
PubMed2004

[Local lysis with alteplase for the treatment of acute embolic leg ischemia following the use of the duett closure device: preliminary results].

PURPOSE: To analyze retrospectively the result of the alteplase lysis therapy of embolic complications following the use of the Duett closure device. METHODS AND MATERIALS: For 3.5 years, the Duett closure device was used in 1,398 angiographies to close the femoral puncture site. The Duett device consists of a balloon and a liquid procoagulant containing collagen and thrombin, which is injected into the puncture tract under endovascular balloon protection of the arterial puncture site. In 9 patients (0.64 %), the procoagulant was incidentally injected into the femoral artery causing acute leg ischemia. Eight patients received local lysis therapy with alteplase via a contralateral femoral access. One patient underwent surgery. On average, 21 mg alteplase (4 - 35 mg) were administered within 14 h (4 - 21 h). The course of the lysis was followed angiographically and clinically. All patients were interviewed by telephone 23 months (4 - 35 months) later. RESULTS: In 3 patients, lysis was complete. In 5 patients, only little thrombotic material remained. In all patients, symptoms of ischemia resolved completely within the first hours after initiation of lysis. In 5 cases, bleeding occurred at the puncture site closed with the Duett device during lysis, including development of a false aneurysm in 2 cases. Complications led to premature termination (n = 2) or interruption of the lysis (n = 3). All complications were treated conservatively. Clinically, long-term sequelae were paresthesia and hypoesthesia in the lower leg and foot in 2 patients treated with lysis, and in the patient who underwent surgery. CONCLUSION: Very rarely occurring embolic complications after use of the Duett closure device can be effectively treated with alteplase lysis. A high rate of complications is to be expected at the puncture site closed with the Duett device.

Acute Disease↗
PubMed2003

[A novel hirudin coating of vascular endoprostheses: experimental results].

PURPOSE: Does hirudin coating improve the patency of iliac artery endoprostheses in comparison to non-hirudin-coated endoprostheses? MATERIALS AND METHODS: Nitinol stents and stentgrafts covered with polytetrafluoroethylene (PTFE) were coated with the polymer polyamino-p-xylylene-co-poly-p-xylylene using chemical vapor deposition (CVD) technique. Hirudin was covalently bound to the surface of the endoprostheses via the amino-group. External factors (mounting of the prosthesis, sterilization, storage time and temperature, release) affecting the hirudin activity were evaluated in vitro. Five types of prostheses were compared in vivo: (1) plain and (2) CVD- and hirudin-coated stents; (3) plain, (4) CVD-coated, and (5) CVD- and hirudin-coated PTFE-stentgrafts. In 20 sheep, 16 protheses of each type were inserted in arteries pretreated with a Fogarty maneuver. The animals were followed for either 1 (n = 10) or 6 (n = 10) months. Immediately after implantation and after 1, 3, and 6 months, intravascular ultrasound (IVUS) and angiography were performed. The vascular specimens were analyzed histologically. RESULTS: Within 10 weeks, the hirudin activity of coated stents dropped 60 % due to external factors; the activity of coated PTFE stentgrafts dropped 20 %. After 1, 3, and 6 months, IVUS and histology revealed a significantly reduced patency of the hirudin-coated stentgrafts compared to the other prostheses. Only IVUS showed a significantly reduced patency of hirudin coated stents after 1 and 3 months compared to plain and CVD-coated PTFE-stentgrafts. The reduced patency was caused by neointimal hyperplasia. CONCLUSIONS: In an experimental setting, hirudin coating did not improve the patency of vascular endoprostheses.

Angiography↗
PubMed2002

[Selective CT mesentericography in the diagnostics of obscure overt intestinal bleeding: preliminary results].

AIM: To evaluate intra-arterial CT mesentericography (CTM) in the diagnostics of severe obscure overt intestinal bleeding in comparison with conventional mesentericography (MG) and surgery. METHODS: In 8 patients (23 - 82 years, mean 59 years), CTM was performed via the catheter left in the superior mesenteric artery after MG to detect the source of bleeding. Early and late-phase spiral CT scans were acquired after administration of contrast medium. Active bleeding was considered to be present if extravasation of contrast medium into the bowel was found. The results of MG and CTM were compared with the results of surgery. RESULTS: With MG active bleeding was found in one patient, with CTM in five patients. In three patients, both MG and CTM were negative. Six patients underwent surgery. Five cases of bleeding detected with CTM were confirmed by surgery. In one case, bleeding found with CTM was not confirmed by surgery. One patient underwent surgery although all imaging procedures were negative. The source of bleeding remained unknown. Surgically, the site of bleeding was located in the jejunum in 3 patients (jejunitis, jejunal ulcers, carcinoid), one patient had a diverticulum in the ascending colon. The colonic bleeding site was correctly localized with CTM, whereas the small bowel bleeding could only roughly be assigned to the proximal or distal jejunum or jejunoileal transition area. CONCLUSION: Preliminary results indicate that selective CTM is superior to MG in the evaluation of severe obscure overt intestinal bleeding.

Adult↗
PubMed2001

[Low-grade malignant peripheral nerve sheath tumor of the neck soft tissues].

BACKGROUND: Malignant Peripheral Nerve Sheath Tumours (MPNST) either grow sporadically, after radiation or chemotherapy respectively. In many cases they are associated with Neurofibromatosis I. Because of the multiform histologic picture they are often difficult to differentiate from other soft tissue tumours. PATIENT: We present the case of a sporadic MPNST which developed from the vagus nerve of a 39-year-old patient following radiation of the neck 7 years before. After complete excision there has been no recurrence up to now. RESULTS AND CONCLUSIONS: Sporadic MPNST of the head and neck are comparatively rare. With regard to the strong association with Neurofibromatosis I and the difficult differential diagnosis to other soft tissue tumours the emphasis should be put on excluding further manifestations of Neurofibromatosis I and of secondary tumours.

Adult↗
PubMed2000

Comparison of two stent-grafts with different porosity: in vivo studies in a sheep model.

PURPOSE: To compare two stent-grafts with a polyurethane-carbonate (PUC) polymer lining of different pore size and water permeability in the iliac arteries of sheep. MATERIALS AND METHODS: Two stent-grafts with an inner PUC-lining of normal and low water permeability (normal, 1,200 mL/min/cm2; low, 280 mL/min/cm2; pressure gradient, 20 mm Hg) were implanted in each of 16 sheep. Hoop strength was two times higher in low-permeable than in normal-permeable stent-grafts. Patency was monitored with use of angiography and intravascular ultrasound (IVUS) after 1, 3, and 6 months. The sheep were killed after 1 or 6 months. Specimens were studied histologically. IVUS and histologic data were analyzed statistically. RESULTS: IVUS measurements showed a wider patent lumen of the low- compared to the normal-permeable prostheses at all time points (P < .03). This is likely due to the greater hoop strength of the low-permeable stent-graft. After 1 month, both types of prostheses demonstrated complete transprosthetic tissue penetration and were covered with neointima and endothelium. The neointimal area was greater in low- than in normal-permeable stent-grafts (1 month, P < .005; 6 months, P < .03). CONCLUSIONS: Presumably, the higher permeability of the normal-permeable stent-grafts led to the reduced neointimal area by improving transprosthetic capillary ingrowth and endothelialization.

Angiography↗
PubMed2000

Suramin inhibits proliferation of human arterial smooth muscle cells in vitro: potential drug for prevention of restenosis by local drug delivery.

PURPOSE: Suramin is known to inhibit proliferation of various tumor cells. This study was performed to investigate the effect of suramin on proliferating human arterial smooth muscle cells (HASMC) and thus to examine its suitability for the prevention of restenosis. METHOD: Proliferation of HASMC was stimulated with human whole blood serum (HWBS), as well as with platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF). Proliferation was assessed by measuring DNA synthesis and cell viability was assessed by measuring mitochondrial activity. RESULTS: Suramin exerted a strong attenuating effect on the proliferation stimulators HWBS, PDGF, and bFGF. A suramin concentration of 0.5 mmol/L, which is approximately twice the dosage used for systemic application, was sufficient for complete neutralization of proliferation stimulation by 10% HWBS added to the cell culture medium. CONCLUSION: The authors' data demonstrate a strong proliferation inhibiting effect of suramin on HASMC in vitro. Because it is known to interact not only with one but with a multitude of relevant growth factors, these results make suramin a most interesting substance for local application for prevention of hyperplastic neointima formation.

Arteries↗
PubMed2000

Recanalization of thrombosed dialysis access with use of a rotating mini-pigtail catheter: follow-up study.

PURPOSE: To evaluate the feasibility, efficacy, and safety of mechanical thrombectomy of occluded dialysis access with use of a rotating mini-pigtail catheter. MATERIALS AND METHODS: Thrombus was fragmented by mechanical action of the rotating pigtail tip (5-mm diameter), while the guide wire exited a sidehole at the pigtail curvature and served as a fixed rotation axis. Twenty-six procedures were performed in 22 patients (12 men, 10 women; mean age, 55.5 years). Native fistulas were treated in 15 instances, polytetrafluoroethylene (PTFE) grafts were treated in 11 instances. Average occlusion time was 20 hours +/- 13 (range, 5-46 hours), average occlusion length was 25.6 cm +/- 10.1 (range, 6-45 cm). Thrombus fragmentation was followed by balloon angioplasty of underlying stenoses. RESULTS: In all 26 procedures, the dialysis access was successfully declotted with subsequent dialysis using the access (clinical success rate, 100%). Handling of the mini-pigtail catheter was simple and rapid, regardless of whether a graft or a native fistula was treated. Average duration of the intervention was 118 minutes +/- 30. Mean primary patency was 165 days +/- 167. Primary patency rate was 82% at 30 days, 65% at 3 months, and 47% at 6 months. There was no evidence of complications due to the thrombus fragmentation procedure. CONCLUSION: The results suggest that declotting of occluded dialysis grafts and fistulas with the mini-pigtail catheter is as effective and safe as other more established percutaneous therapies. It may serve as an easy-to-handle, low-budget alternative to current thrombectomy devices.

Adult↗
PubMed2000

Percutaneous treatment of thrombosed primary arteriovenous hemodialysis access fistulae.

BACKGROUND: We reviewed the efficacy of percutaneous intervention in acute thrombotic occlusion of native arteriovenous (AV) fistulae for hemodialysis. METHODS: Eight-one percutaneous procedures were performed in 54 patients presenting with a clotted native dialysis fistula. There were 60 cases of a long-segment thrombosis of the fistula. In 20 cases, a small thrombus usually caused by an underlying severe stenosis was observed. A proximal arterial occlusion was seen in one case. Treatment depended on clot size and included balloon dilation (N = 20), mechanical thrombectomy with various devices (N = 58), as well as pharmacomechanical thrombolysis (N = 3). RESULTS: Full restoration of flow was established in 72 cases (88.9%). Early reobstruction within 14 days occurred in eight cases (11.1%). Primary patency rates after a 1-, 3-, 6-, and 12-month period were 74, 63, 52, and 27%, respectively. Overall fistula patency was 75% after 3 months, 65% after 6 months, 51% after 12 months, and 22% after 24 months. CONCLUSIONS: Acute thrombotic occlusion of native AV fistulae is a major complication of hemodialysis. The results of treatment are believed to be less successful than thrombosis treatment in synthetic grafts. Our results, however, indicate the efficacy of percutaneous treatment in native fistulae, and demonstrate comparable technical results and patency rates.

Adult↗
PubMed2000

[Endoluminal vascular prostheses].

Endoluminal vascular prostheses that can be implanted by percutaneous routes represent the most recent development in vascular interventional radiology. Various commercially available types of prosthesis are presented and the construction principles and applications are described. At present secure indications for the implantation of endoluminal prostheses are limited to the elimination of aneurysms and arteriovenous fistulae of the large vessels near the trunk in sections that do not cross a joint. The wide use in peripheral occlusive diseases cannot yet be recommended because confirmed data are not available.

Biocompatible Materials↗
PubMed2000

[Temporary implantation of a metal stent in Vater's ampulla. Evaluation of early changes of the bile ducts in an animal study].

PURPOSE: Evaluation of temporary stent implantation in the papilla of vater and the subsequent alterations of the bile ducts in a controlled animal study. MATERIAL AND METHODS: In seven domestic pigs the papilla of vater was stented with a nitinolelastalloy-strecker stent over a period of three days. The microscopic and macroscopic changes of the biliary tract and the serologic parameters were judged. RESULTS: In three cases a slight widening of the peripheric bile ducts was found. With the exception of a mild elevation of lactate dehydrogenase the serological parameters remained normal. The explantation of the stent two possible in six cases. A thickening of the outer layers of the bile ducts and a low to middle grade injury of the mucosa were found histologically. CONCLUSION: A temporary stent implantation in the papilla of vater is feasible. The mucosal injuries caused by the temporary stent placement may be fully repairable. The method seems to be suitable for prolonged dilatation of benign stenoses.

Alloys↗
PubMed2000

[Changes in the region and the proximal aneurysm neck after endovascular repair of infrarenal aortic aneurysms].

PURPOSE: To analyze short and mid-term changes of the proximal aneurysm neck and to evaluate renal function after endovascular repair of infrarenal abdominal aortic aneurysms. MATERIALS AND METHODS: 24 of 29 patients, who were treated endoluminally with the bifurcated Vanguard Stent graft between 1997 and 1999 underwent spiral CT follow-up after 1, 3, 6 and every 12 months. Mean follow-up period was 10.5 months (3-32 months). Follow-up included spiral CT scanning. The aortic diameter as well as cross-sectional area were measured. Stent graft position and renal perfusion were checked by spiral CT. Serum creatinine levels were determined preoperatively and during follow-up. RESULTS: Supra- and infrarenal aortic sizes remained stable. No correlation to the distance between the stent-graft and the renal arteries was observed. Caudal migration of the stent-graft with an average of 6.5 (3-15) mm occurred in 13 patients. Cranial migration was observed in 3 patients. Uncovered stent wires partially overlapped at least one renal artery in 18 patients. No renal infarction occurred. No significant increase of the serum creatinine level was found. CONCLUSION: The risk of proximal endoleakage due to post-interventional dilatation of the aorta abdominalis seems to be low. Insufficient stent graft fixation requires a wide distance between the proximal end of the stent graft and the aneurysm. In the mid-term uncovered stent wires overlapping the renal arteries had no relevant influence on renal function.

Aged↗
PubMed1999

[The Perflex stent, a new balloon-expandable vascular stent: the initial clinical results].

PURPOSE: Clinical evaluation of a newly developed balloon-expandable vascular stent. METHOD: Participating in a multi-center study our clinic enrolled 12 patients with 15 iliac artery stenoses (Fontaine IIa-III) that were treated with the new stent. Three patients had bilateral stenoses. The mean ankle-brachial index (ABI) at rest was 0.76 +/- 0.25 (+/- 1 standard deviation), the mean ABI after exercise was 0.47 +/- 0.20. Indication for stent insertion was a residual trans-lesion pressure gradient > or = 10 mmHg after balloon angioplasty. Follow-up included clinical examination, measurements of the ABI at rest and after exercise, and colour duplex ultrasound (CDS) on the day of hospital dismissal and 1, 6 and 12 months after stent insertion. RESULTS: 16 stents were placed successfully. One stenosis was treated with two stents. Acute complications did not occur. The Fontaine stage increased by at least one stage in all patients. The ABI at rest rose to 0.91 +/- 0.26, the ABI after exercise to 0.86 +/- 0.29. During follow-up one stent occlusion, one stenosis proximal to a stent, and CDS-findings suggesting restenosis in two further stents were observed. CONCLUSIONS: It appears that the Perflex stent may be used in the iliac arteries with a success rate similar to other stents. However, this preliminary result has to be confirmed in a larger series and after a longer follow-up.

Aged↗
PubMed1998

[Dose and contrast medium reduction in intravenous digital subtraction angiography by bolus sequence].

PURPOSE: This study evaluates the dose area product, the amount of contrast media and the examination quality of the bolus chasing technique compared to the single-step technique in intravenous digital subtraction angiography. MATERIAL AND METHODS: 15 examinations each with bolus chasing and single-step technique were compared. The dose area product and the volume of contrast media were recorded. The examination quality was scored by two examiners. RESULTS: With bolus chasing the volume of the administered contrast media could be decreased on average by 114 ml (43%). The difference between the dose area product of bolus chasing (722 dGy/cm2) and single-step technique (1910 dGy/cm2) was significant. No significant difference in examination quality was found. CONCLUSIONS: The intravenous bolus chasing technique is a practicable method. Compared to the single-step technique it allows a remarkable dose reduction and a low consumption of contrast media without restriction of examination quality.

Angiography, Digital Subtraction↗
PubMed1998

[Novel endoluminal stents for the treatment of arterial fistulas and perforations].

PURPOSE: To evaluate the use of polycarbonate-polyurethane (Corethane) stented grafts for the treatment of arteriovenous fistulas and arterial perforations. MATERIALS AND METHODS: 4 patients at the age of 34 to 81 underwent percutaneous insertion of corethane endoluminal grafts. Two patients had an arterial fistula--one iliaco-iliac, one brachio-brachial. Two patients underwent treatment to seal arterial perforations that occurred in the external iliac artery in one and in a femoral venous bypass in another. RESULTS: In all cases the communication or leakage was sealed by the endograft in place but had to be combined with a detachable balloon in om case. In three patients, a longer follow-up became available, one patient died three weeks after treatment from unrelated causes. While two stent grafts remained open for 15 and 24 months, one patient experienced stent graft occlusion three months after treatment. CONCLUSIONS: Corethane stent grafts are helpful to seal short-neck arteriovenous fistulas and arterial perforations even under emergency conditions.

Adult↗
PubMed1998

[Stent placement with real time MRI guidance: initial animal experiment experiences].

PURPOSE: The aim of this study was to test the feasibility of iliac artery stent placement under MR guidance with real-time MR radial scanning in an animal model. MATERIALS AND METHODS: The experiments were performed on three pigs in a 1.5 T scanner. Radial scanning with a gradient echo technique (TR 8.4 ms, TE 3.6 ms, flip angle 10 degrees) was used. A dedicated backprojector performed the reconstruction of the raw data in real-time. The resulting MR-images were displayed on LCD screens beside the magnet. The sliding window reconstruction technique allowed image acquisition at a frame rate of 16 images per second. MR-compatible self-expanding stents with a diameter of 8 mm and a length of 3 cm were placed into the left iliac artery. Their positions were verified by digital subtraction angiography (DSA) and compared to MRI. RESULTS: All stents were successfully placed. Stent positions as monitored by real-time MR were identical to those seen on DSA images. The time needed for exact positioning of the scan plane ranged from 15 to 30 minutes. Stent placement itself took 8 minutes on average. CONCLUSION: Radial scanning applied together with the sliding window reconstruction technique allows placement of stents in iliac arteries under real-time MR control.

Angioplasty, Balloon↗
PubMed1997

[Sutureless vascular end-to-side anastomosis: an in-vivo test of a percutaneous concept in the animal model].

PURPOSE: To test a percutaneous concept for creation of a sutureless terminolateral vascular anastomosis in vivo. MATERIAL AND METHOD: By creating sideholes into the middle portion of a stent and a stent graft, both implants could be arranged in a Y-shaped configuration. An arteriovenous shunt was created in 3 sheep between the left carotid artery and the left external jugular vein. A stent graft was partially inserted into the venous lumen. Axial venous patency was restored by placing a stent through the sidehole into the graft lumen from an upstream puncture site. Graft patency was maintained by placing the sidehole of the stent at the bridging point between stent graft and stent with no stent struts crossing. Arterial end-to-end anastomosis was performed by retrograde placement of a stent graft into the arterial lumen. Both anastomoses were connected by a silicone tube. RESULTS: In all cases, a venous end-to-side anastomosis was created that was blood-tight and safely secured into the vascular lumen. CONCLUSION: Y-shaped configuration of stent and stent grafts through sideholes allows creation of sutureless end-to-side anastomoses in vivo.

Anastomosis, Surgical↗
PubMed1997

Color-coded duplex sonography of experimentally induced multilevel stenosis. Evaluation of poststenotic Doppler spectrum.

RATIONALE AND OBJECTIVES: The authors evaluated the influence of a proximal arterial stenosis on the poststenotic doppler spectrum of a second, distal stenosis and determined duplex parameters, which permitted description of the severity of the distal stenosis. METHODS: Moderate (ie, 50%) and severe (ie, 90%) stenoses of the distal aorta and the distal iliac arteries of 10 pigs were created surgically and characterized by angiography. All possible combinations of moderate and severe stenoses were examined. The Doppler spectrum was depicted in the distal iliac and distal femoral arteries of both limbs and analyzed by use of maximum and minimum flow velocity (Vmax, Vmin), acceleration index (modified Handa index), acceleration time, and pulsatility index. RESULTS: In cases of moderate as well as severe proximal stenosis, acceleration index, acceleration time, and pulsatility index of the poststenotic curve of the distal stenosis were significantly reduced (P < 0.05). Independent of the severity of the proximal stenosis, differentiation of moderate as well as severe distal stenosis was possible (P < 0.05) with these parameters. CONCLUSIONS: Despite interference of spectral curves in proximal and distal stenosis, duplex sonography enabled the differentiation of experimental aortic iliac multilevel stenosis.

Animals↗