Jörg Schmehl

Universitätsklinikum Tübingen, Tübingen, Baden-Württemberg, Germany

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Publications (35)80.51 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Since the introduction of endovascular aneurysm repair (EVAR) in 1991, the endovascular therapy with newest stent grafts has assumed a prominent role in the clinical management of abdominal aortic aneurysms (AAA) with a superior perioperative mortality of EVAR and an equivalent mid-term outcome, compared to open surgery. Newest techniques using chimney or periscope grafts and customized fenestrated and branched stent grafts allow the endovascular treatment of complex pararenal AAA. This article reviews EVAR in the treatment of AAA, evidence based results and advanced indication by newest interventional techniques and technical developments. Key Points: • EVAR has become standard treatment of abdominal aortic aneurysm with equivalent results to open surgery.• Technical advancements and the introduction of newest stent grafts continually expand the indication of EVAR.• Chimney- and periscope grafts as well as custom-made prothesis systems allow endovascular treatment of complex para- and suprarenal aneurysms. Citation Format: • Ketelsen D, Thomas C, Schmehl J et al. Endovascular Aneurysm Repair of Abdominal Aortic Aneurysms: Standards, Technical Options and Advanced Indications. Fortschr Röntgenstr 2014; 186: 337 - 347.
    RöFo - Fortschritte auf dem Gebiet der R 04/2014; 186(4):337-347. · 2.76 Impact Factor
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    ABSTRACT: Purpose : To present the 12-month results of a trial investigating the effects of dual antiplatelet therapy on target lesion revascularization (TLR) after balloon angioplasty ± stenting in the femoropopliteal segment. Methods : A prospective, randomized, single-center, double-blinded and placebo-controlled clinical trial randomly assigned 40 patients to receive pre- and postinterventional therapy with aspirin and clopidogrel. Another 40 patients received the same doses of aspirin and placebo instead of clopidogrel. Clopidogrel and placebo were stopped after 6 months, and patients remained on aspirin only. At 12 months after the intervention, 36 clopidogrel patients and 37 placebo patients were reevaluated. Results : At 6 months, clopidogrel patients had significantly lower rates of TLR compared to placebo patients [2 (5%) vs. 8 (20%), p=0.04]. After stopping clopidogrel/placebo after 6 months, there was no significant difference in TLR at 12 months after treatment [9 (25%) clopidogrel vs. 12 (32.4%) placebo, p=0.35]. Mortality was 0 vs. 1 in the placebo group at 6 months (p=0.32) and 0 vs. 3 at 12 months (p=0.08). Conclusion : In contrast to the first report of a reduction in the TLR at 6 months, this advantage of dual antiplatelet therapy does not persist after stopping clopidogrel. Prolonged dual therapy (>6 months) should be considered in patients who are at high risk for restenosis.
    Journal of Endovascular Therapy 10/2013; 20(5):699-706. · 3.59 Impact Factor
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    ABSTRACT: The portosystemic pressure gradient is an important factor defining prognosis in hepatic disease. However, noninvasive prediction of the gradient and the possible reduction by establishment of a TIPSS is challenging. A cohort of patients receiving TIPSS was evaluated with regard to imaging features of collaterals in cross-sectional imaging and the achievable reduction of the pressure gradient by establishment of a TIPSS. In this study 70 consecutive patients with cirrhotic liver disease were retrospectively evaluated. Patients received either CT or MR imaging before invasive pressure measurement during TIPSS procedure. Images were evaluated with regard to esophageal and fundus varices, splenorenal collaterals, short gastric vein and paraumbilical vein. Results were correlated with Child stage, portosystemic pressure gradient and post-TIPSS reduction of the pressure gradient. In 55 of the 70 patients TIPSS reduced the pressure gradient to less than 12mmHg. The pre-interventional pressure and the pressure reduction were not significantly different between Child stages. Imaging features of varices and portosystemic collaterals did not show significant differences. The only parameter with a significant predictive value for the reduction of the pressure gradient was the pre-TIPSS pressure gradient (r=0.8, p<0.001). TIPSS allows a reliable reduction of the pressure gradient even at high pre-interventional pressure levels and a high collateral presence. In patients receiving TIPSS the presence and the characteristics of the collateral vessels seem to be too variable to draw reliable conclusions concerning the portosystemic pressure gradient.
    European journal of radiology 08/2013; · 2.65 Impact Factor
  • Digestive and Liver Disease 04/2013; 45:S250. · 2.89 Impact Factor
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    ABSTRACT: PURPOSE: The efficacy of drug-eluting balloons has been demonstrated in clinical trials. The drug predominantly used is paclitaxel because of its lipophilic properties and the rapid onset of action. The aim of the investigation was to evaluate the feasibility and efficacy of an alternative balloon coating with rapamycin that can be applied on site. METHODS: The balloon coating (3.0/18 and 3.0/12 mm, Cathy No. 4, Translumina GmbH) with rapamycin was conducted with a coating machine (Translumina GmbH). Concentrations were 2, 2 × 2, 3, and 4 %. Measurements regarding the amount of substance released to the vessel wall were carried out on explanted porcine coronaries by means of ultraviolet and visible-light spectroscopy. Inflation time varied between 30 and 120 s. The biological effect of the coating was evaluated in a porcine peripheral overstretch and stent implantation model. RESULTS: The amount of rapamycin on the balloon surface ranged from 558 ± 108 μg for the 2 % solution to 1,441 ± 228 μg in the 4 % solution. An amount of 95 ± 63-193 ± 113 μg was released into the vessel wall. The quantitative measurements of the angiographic examinations 4 weeks after treatment revealed a reduction of diameter stenosis from 20.6 ± 17.4 % in the control group to 11.6 ± 5.5 % in the drug-eluting balloon group. CONCLUSION: A balloon coating with rapamycin omitting an excipient is possible with a dose-adjustable coating machine. However, the biological effects are moderate, which make further optimization of the coating process and evaluation of appropriate excipients necessary.
    CardioVascular and Interventional Radiology 02/2013; · 2.09 Impact Factor
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    ABSTRACT: Purpose: Comparison of dose area products (DAP) in diagnostic angiography procedures between an image intensifier (II) and a flat panel detector (FPD) angiography system and the evaluation of DAP/body mass index (BMI) dependency. Materials and Methods: An image intensifier system or a flat panel detector system was used to perform 571 diagnostic angiographies (n = 328 and n = 243, respectively) of 5 different types: peripheral arterial, venous, single leg, abdominal and upper extremity. The results were retrospectively analyzed. The DAP, fluoroscopy time (t) and the number of series of the respective interventions as calculated by the respective machines was compared for all interventions and for the respective subtypes and machines. The BMI dependency was calculated separately for both machines for all interventions by subdividing the patients into 6 BMI classes defined by the WHO. Results: The average DAP for all diagnostic interventions was 1958.9 cGy×cm2 (t = 384.6 s, n = 7.85 series) for the II and 2927.4 cGy×cm2 (t = 267.4 s, n = 7.02 series) for the FPD. Group-dependent differences ranged between + 21 and + 252 % when using the FPD system. After time standardization, the respective increases were found to be 120 % for the FPD system. The DAPs increased considerably in patients with higher BMIs (766.7 cGy × cm2 - 6892.6 cGy × cm2, II machine, 950.5 cGy × cm2 - 12 487.7 cGy × cm2, FPD machine) with a greater DAP gain seen for the FPD. The average duration of the interventions was higher using the II machine. Conclusion: The use of an FPD system led to higher DAP values compared to the II system in diagnostic angiographic procedures. In addition, increased BMI values led to higher DAPs, especially for the FPD machine. However, the average fluoroscopy times were shorter.
    RöFo - Fortschritte auf dem Gebiet der R 11/2012; · 2.76 Impact Factor
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    ABSTRACT: Background Sufficient radiopacity of stents is a prerequisite for safe interventions and minimization of the radiation dose for the patient and the interventionist. Modern nitinol stents are considered less radiopaque compared to formerly used stents.PurposeTo evaluate the objective detection rate (ODR) and the subjective radiopacity score (SRS) of four self-expanding nitinol stents with their markers on a phantom human pelvis.Material and Methods We evaluated the ODR (as a percentage of correctly identified stents) and the SRS (on a scale from 0 = not visible to 4 = excellent visibility) for four self-expanding nitinol stents (SinusSuperflex, SMART, Luminexx, Zilver) with 8 mm diameter and 40 mm length. Stents were placed on a phantom human pelvis and images of the stents were taken in four different positions (right and left lumbosacral joint and near the right and left limbus acetabuli) using the following modes: spotfilm, pulsed fluoroscopy (4, 7.5, 15, and 30 pulses/min) and at three different digital magnification modes. Dose area products (DAPs) were assessed.ResultsODR and SRS, respectively, were significantly increased for the SMART stent compared to all other tested stents (P < 0.05): SMART 93.53% and 2.43, SinusSuperflex 90.81% and 2.21, Luminexx 90.39% and 2.20, and Zilver 89.28% and 2.21. ODR was significantly reduced in position 3 where the bone overlap was more pronounced for all stents (detection rates 77.14-79.56%). An increase in magnification significantly improved the ODR and SRS for all stents (70.33-99.25% and 1.07-3.28, respectively, P < 0.05). Increased pulsing frequency did not improve the ODR of the various stents but did increase the DAP.Conclusion The SMART stent had the best overall performance. In the presence of bone overlap, all self-expanding nitinol stents had poor results. Increased pulsing frequency did not improve ODR or SRS but did increase the DAP. Use of digital magnification modes had no effect on DAP increasing ODR and SRS.
    Acta Radiologica 09/2012; · 1.35 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the initial tumour response after one, respectively, two transarterial chemoembolizations (TACE) with drug-eluting (DC) beads in patients with hepatocellular carcinoma (HCC). A total of 26 patients with clinically approved HCC underwent one or two TACE with DC Beads within 6 weeks and were evaluated after 12 weeks by MRI or computed tomography on the basis of the modified Response Evaluation Criteria in the Solid Tumours guidelines for HCC. For improved comparability of both groups, 16 patients were matched in terms of Child-Pugh classification, Barcelona classification of liver cancer, age and sex. The overall tumour response showed progressive disease in 11% and an objective response in 89% for the double TACE group compared with progressive disease in 29.5%, objective response in 34.5% and stable disease in 35% for the single TACE group. In the matched population, absolute tumour shrinkage was 61.1±28.3% for the double TACE group and 14.1±38.5% for the single TACE group (P<0.05). This retrospective study shows significantly higher tumour shrinkage in patients who underwent two TACE within 6 weeks compared with patients who underwent a single intervention in terms of the initial response rate after 12 weeks. It emphasizes the use of matched populations for the evaluation of tumour response in HCC after TACE.
    European journal of gastroenterology & hepatology 08/2012; 24(11):1325-32. · 1.66 Impact Factor
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    ABSTRACT: To investigate the influence of dual antiplatelet therapy vs. aspirin alone on local platelet activation and clinical endpoints in patients with PAD treated with endovascular therapy. Patients received either 500 mg aspirin and 300 mg clopidogrel before intervention followed by a daily dose of 100 mg aspirin and 75 mg clopidogrel for 6 months, or the same doses of aspirin plus placebo instead of clopidogrel. Primary endpoints were local concentrations of platelet activation markers β-thromboglobulin and CD40L, and the rate of patient's resistant to clopidogrel. Secondary endpoints included the clinical development 6 months after the intervention. Eighty patients, 40 in each group, were enrolled. The median peri-interventional concentration of β-TG was 224.5 vs. 365.5 (P = 0.03) in the clopidogrel and placebo group. The concentration of CD40L was 127 and 206.5 (P = 0.05). Thirty per cent of patients who had received clopidogrel were resistant. Two clopidogrel and eight placebo patients required TLR (P = 0.04). The clopidogrel patients who needed revascularisation were both resistant to clopidogrel. Minor bleeding complications occurred in one clopidogrel and two placebo patients. Dual antiplatetet therapy reduces peri-interventional platelet activation and improves functional outcome without higher bleeding complications. An individual tailored dual antiplatelet therapy seems desirable for endovascularly treated patients with PAD.
    European Radiology 05/2012; 22(9):1998-2006. · 4.34 Impact Factor
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    ABSTRACT: The objective of this study was to compare the performance and radiation doses of a flat-panel detector (FPD) angiography machine with an image intensifier (II) angiography machine. Images of four nitinol stents (Sinus-SuperFlex, SMART, Luminexx, and Zilver stents) in a phantom of a human pelvis were acquired on an FPD system (Axiom Artis) and an II system (Fluorospot TOP) using the following modes: spot-film, continuous fluoroscopy (4, 7.5, 15, and 30 pulses/s), and three amplification modes. Objective stent detection rates and subjective radiopacity scores (scale: 0 [not visible] to 4 [excellent visibility]) were calculated. The radiation doses evaluated by the respective machines were compared. Over all modes and stents, the mean objective correct stent detection rates and mean subjective radiopacity scores were 89.49% and 1.81, respectively, for the Axiom Artis and 91.00% and 2.26 for the Fluorospot TOP. The stent detection rates over all modes for the SMART and Luminexx stents were better using the Axiom Artis machine (97.61% vs 93.55% and 98.28% vs 90.41%, respectively) and those for the Sinus-SuperFlex and Zilver stents were better using the Fluorospot TOP machine (90.83% vs 83.56% and 89.29% vs 80.50%). The subjective radiopacity scores of stent visibility were worse for the Axiom Artis than the Fluorospot TOP for all stents except the Luminexx stent (mean score, 2.34 vs 2.21, respectively). The objective stent detection rates and subjective radiopacity scores improved using the spot-film mode and with raising amplification, whereas increases in the fluoroscopy pulsing frequency did not improve stent detection rates or radiopacity scores for either machine. The radiation doses at continuous fluoroscopy were approximately 90% higher for the Axiom Artis than for the Fluorospot TOP (2.60 vs 1.41 μGy/m(2) at 30 pulses/s, respectively). The objective correct stent detection rates were similar for both machines with differences in detection for the respective stents. The subjective radiopacity scores were almost always better for the Fluorospot TOP machine. Also, the Axiom Artis machine generated approximately 90% higher radiation doses in fluoroscopy. For both machines, using a higher fluoroscopy pulsing frequency had no positive effect on objective correct stent detection rates or subjective radiopacity scores.
    American Journal of Roentgenology 04/2012; 198(4):946-54. · 2.74 Impact Factor
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    ABSTRACT: PURPOSE: To evaluate in vivo the role of RAGE (receptor for advanced glycated end products) in the development of restenosis and neointimal proliferation in RAGE-deficient knockout (KO) mice compared with wild-type (WT) mice in an animal model. MATERIALS AND METHODS: Sixteen WT and 15 RAGE-deficient mice underwent microvascular denudation of the common femoral artery under general anaesthesia. Contralateral arteries underwent a sham operation and served as controls. Four weeks after the intervention, all animals were killed, and paraformaldehyde-fixed specimens of the femoral artery were analysed with different stains (hematoxylin and eosin and Elastica van Gieson) and several different types of immunostaining (proliferating cell nuclear antigen, α-actin, collagen, von Willebrand factor, RAGE). Luminal area, area of the neointima, and area of the media were measured in all specimens. In addition, colony-formation assays were performed, and collagen production by WT smooth muscle cells (SMCs) and RAGE-KO SMCs was determined. For statistical analysis, P < 0.05 was considered statistically significant. RESULTS: Four weeks after denudation, WT mice showed a 49.6% loss of luminal area compared with 14.9% loss of luminal area in RAGE-deficient mice (sham = 0% loss) (P < 0.001). The neointima was 18.2 (*1000 μm(2) [n = 15) in the WT group compared with only 8.4 (*1000 μm(2) [n = 16]) in the RAGE-KO group. RAGE-KO SMCs showed significantly decreased proliferation activity and production of extracellular matrix protein. CONCLUSION: RAGE may be shown to play a considerable role in the formation of neointima leading to restenosis after vascular injury.
    CardioVascular and Interventional Radiology 12/2011; · 2.09 Impact Factor
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    ABSTRACT: Malignancies of the aortic wall represent a rare condition, and only a few reports have covered cases of sarcomas arising at the site of a prosthesis made of Dacron. A coincidence with endovascular repair has only been reported in one case to date. We report a patient with epithelioid angiosarcoma and metastatic disease, which was found in an aneurysmal sac after endovascular aortic repair for abdominal aortic aneurysm.
    CardioVascular and Interventional Radiology 07/2011; 35(1):190-3. · 2.09 Impact Factor
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    ABSTRACT: The authors report two cases of stent-assisted embolization (SAE) in the aorta. In one case, SAE was performed for treatment of a pseudoaneurysm; the procedure consisted of stent placement and embolization with an AMPLATZER Vascular Plug and detachable coils through the stent struts. In the second case, SAE was performed to stop acute bleeding from an aortoureteral fistula. Before SAE in this case, the aortic bifurcation was reconstructed with self-expandable and balloon-expandable stents. SAE was technically successful in both cases. SAE for aortic pathologic processes may be useful in selected cases as an alternative to surgery or endovascular stent-graft therapy.
    Journal of vascular and interventional radiology: JVIR 04/2011; 22(4):563-8. · 1.81 Impact Factor
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    ABSTRACT: Restenosis is still one of the major limitations after angioplasty. A therapeutic treatment combining β-irradiation and pharmacologic cyclooxygenase-2 inhibition was employed to study the impact on vascular smooth muscle cells (SMCs). The effects of meclofenamic acid in combination with yttrium-90 ((90)Y) on cell growth, clonogenic activity, cell migration, and cell cycle distribution of human aortic SMCs were investigated. Treatment was sustained over a period of 4 days and recovery of cells was determined until day 20 after initiation. The hypothesis was that there is no difference between control and treated groups. A dose-dependent growth inhibition was observed in single and combined treatment groups for meclofenamic acid and β-irradiation. Cumulative radiation dosage of 8 Gy completely inhibited colony formation. This was also observed for 200 μM meclofenamic acid alone or in combination with minor β-irradiation dosages. Results of the migration tests showed also a dose dependency with additive effects of combined therapy. Meclofenamic acid 200 μM alone and with cumulative β-irradiation dosages resulted in an increased G2/M-phase share. Incubating human SMCs with meclofenamic acid and (90)Y for a period of 4 d (ie, 1.5 half-life times) resulted in an effective inhibition of smooth muscle cell proliferation, colony formation, and migration.
    Journal of vascular and interventional radiology: JVIR 03/2011; 22(5):623-9. · 1.81 Impact Factor
  • CardioVascular and Interventional Radiology 03/2011; 34(5):1094-7. · 2.09 Impact Factor
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    ABSTRACT: Rhenium-186 ((186)Re) and rhenium-188 ((188)Re) are promising radionuclides for the inhibition of restenosis after percutaneous transluminal angioplasty or other vascular interventions. Until now the maximal dose tolerance of endothelial cells has not been clearly known. To characterize the effects of local irradiation treatment, human aortic endothelial cells (ECs) were incubated with different doses of (186)Re and (188)Re. Two days after plating, ECs received treatment for a period of 5 days. The total radiation doses applied were 1, 4, 8, 16, and 32 Gy. On days 1, 3, 5, 7, and 12 after initial rhenium incubation, cell growth, clonogenic activity, cell-cycle distribution, and cytoskeletal architecture were evaluated. From the first day on, a dose-dependent growth inhibition was observed. Cumulative doses of ≥32 Gy caused a weak colony formation and significant alterations in the cytoskeletal architecture. An increased fraction of cells in G2/M phase was seen for cumulative radiation doses of ≥16 Gy. Interestingly, there were no significant differences between (186)Re and (188)Re. Even for low dose rates of β particles a dose-dependent proliferation inhibition of ECs is seen. Doses beyond 32 Gy alter the cytoskeletal architecture with possibly endothelial dysfunction and late thrombosis.
    CardioVascular and Interventional Radiology 11/2010; 34(4):816-23. · 2.09 Impact Factor
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    ABSTRACT: The objective of this investigation was to evaluate 6 magnetic resonance contrast media (CM) with regard to their different effects on human embryonic lung fibroblasts (HEL-299). Human embryonic fibroblasts (HEL-299) were incubated with 1x, 5x, 10x, and 20x of the normal molar blood concentration (1x, 5x, 10x, 20x conc.) reached through routine contrast media applications for MRI examinations. Four gadolinium-based CM, ie, Gadovist, Magnevist, Multihance, Omniscan, Teslascan (Manganese-based), and Resovist (Iron-based), with incubation periods over 4 hours and 24 hours were investigated. Proliferation kinetics, colony formation, and viability assays were performed after 4 and 24 hours of treatment. Apoptotic cells were quantified after tetramethylrhodamine ethyl ester staining following 24 hours of CM media incubation (20x conc.) by fluorescence activated cell sorting cytometry. Furthermore, immunofluorescence images with vimentin staining were obtained (20x conc., 24 hours treatment). Cell cycle analysis was performed after 24 hours of incubation and 20x conc. directly after incubation and 24 hours later (fluorescence activated cell sorting cytometry). The proliferation kinetics performed with 20x conc. revealed a persistent increase in cell numbers until day 11 for all CM without significant differences after 4 hours of incubation. A significant reduction in initial cell numbers was recorded in the 24-hours-group after 4 days of CM incubation with Magnevist, Multihance, Omniscan, and Teslascan. Solely cells incubated with Resovist and Gadovist failed to show decreased cell numbers when compared with the control group. However, a considerable cell regain occurred afterward reaching control-group levels on day 21. Colony numbers were significantly reduced (about 20%, respectively) with Magnevist at 10x and 20x conc., as well as Omniscan and Multihance at 20x conc. when compared with all other groups, P < 0.05. Cell-cycle distribution showed a reduction of S-phase cells for Magnevist, Omniscan, and Multihance (2.9%-10.5%) when compared with Gadovist, Resovist and Teslascan (16.7%-21.0%). Twenty-four hours after incubation, the percentiles of cells in S-phase were significantly increased for Magnevist, Omniscan, and Multihance (31.4%-38.5%) when compared with Gadovist, Resovist, and Teslascan (18.6%-26.8%), P < 0.05. Viability was not impaired by administration of any CM and no apoptosis was seen after tetramethylrhodamine ethyl ester staining at 24 hours of incubation. Cell morphology remained unchanged in vimentin-staining for all CM and conditioning regimens. No toxic effects on embryonic fetal lung fibroblasts were detectable after 4 and 24 hours of incubation in 6 MRI CM and 10x to 20x conc. in our setting. Antiproliferative effects, initially detected with Magnevist, Omniscan and Multihance, were rapidly compensated for.
    Investigative radiology 09/2010; 45(9):513-9. · 4.85 Impact Factor
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    ABSTRACT: The study was designed as a feasibility trial to evaluate the use of GP IIb/IIIa blockade in connection with drug eluting stents, bare stents and PTA only. Sixty patients with current ulcers were randomly assigned to receive abciximab plus a sirolimus coated stent (N.=14), abciximab plus a bare stent (N.=16), abciximab plus PTA (N.=14) and PTA alone (N.=19). Angiographic control was performed at two and six months. Recanalization was successful in all cases. Two month restenosis rate was 9%, 45.5%, 67% and 46%. At six month follow-up restenosis rate was 9%, 67%, 75% and 58%, respectively; 14% of all patients had major amputations within six months. Adjunctive administration of abciximab during peripheral arterial intervention below the knee was found to be safe. Sirolimus coated stent administration was followed by a higher patency rate.
    The Journal of cardiovascular surgery 04/2010; 51(2):203-12. · 1.37 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 03/2010; 182. · 1.96 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 03/2010; 182. · 1.96 Impact Factor

Publication Stats

163 Citations
80.51 Total Impact Points


  • 2008–2013
    • Universitätsklinikum Tübingen
      • Division of Diagnostic and Interventional Radiology
      Tübingen, Baden-Württemberg, Germany
  • 2006–2013
    • University of Tuebingen
      • Department of Radiology
      Tübingen, Baden-Württemberg, Germany