Thomas Schmitz-rixen - Academia.edu (original) (raw)

Papers by Thomas Schmitz-rixen

Research paper thumbnail of Arteriogenesis and Therapeutic Neovascularization

Bad Nauheim, where she started to decipher the molecular mechanisms of arteriogenesis. After a sh... more Bad Nauheim, where she started to decipher the molecular mechanisms of arteriogenesis. After a short detour on stem cells, she again focused on arteriogenesis, becoming a leading expert in the field. By using a peripheral model of arteriogenesis, she demonstrated that collateral artery growth is a matter of innate immunity, and presented a blueprint of sterile inflammation, which is locally triggered by extracellular RNA.

Research paper thumbnail of Dacron-Ummantelung autologer Venenbypasses – Erste klinische Erfahrungen mit Provena®

Einleitung: Autologe Vena saphena magna ist Gold-Standard für Gefäßrekonstruktionen unterhalb des... more Einleitung: Autologe Vena saphena magna ist Gold-Standard für Gefäßrekonstruktionen unterhalb des Leistenbandes. Bei variköser Degeneration muss auf dieses überlegene Bypassmaterial jedoch verzichtet werden. Die vorliegende multizentrische Pilotstudie wurde durchgeführt,[for full text, please go to the a.m. URL]

Research paper thumbnail of Editorial Note for Journal of Vascular Medicine and Surgery

Journal of Vascular Medicine & Surgery, 2020

I am delighted to introduce the Journal of Vascular Medicine & Surgery (JVMS) a rapid peer review... more I am delighted to introduce the Journal of Vascular Medicine & Surgery (JVMS) a rapid peer reviewed journal which is a valuable source of information for scholars, researchers, professionals, and students, providing in-depth perspectives on intriguing contemporary topics of Vascular Medicine. Built on an ethos of openness, we are passionate about working with the global academic community to promote open scholarly research to the world. I am pleased to announce that, 3 issues of the 8 th Edition were published online well within the time and the print issues were also brought out and dispatched within 30 days of publishing the issue online during the year of 2020. The major objective of JVMS is to publish up-to-date, high-quality and original research papers alongside relevant and insightful reviews. The Journal aims to flourish and to maintain the standards in Vascular Medicine research and practices, providing an excellent platform and opportunity to present evidence based researc...

Research paper thumbnail of Pflegepersonalausstattung des Krankenhauses und Patientenoutcome

Research paper thumbnail of „Dem Nachwuchs verpflichtet“

Research paper thumbnail of Panvaskuläre Medizin – Professionalität, Perfektion und Vision

Research paper thumbnail of Gefäßchirurgie

Allgemein- und Viszeralchirurgie II - Spezielle Operative Techniken, 2015

Research paper thumbnail of Stimulation des Aktin-Metabolismus ist ein Schlüsselmechanismus des Kollateralwachstums nach Gefäßverschluss - Bedeutung einer permanenten Erhöhung der longitudinalen Schubspannung

Deutsche Gesellschaft für Chirurgie, 2004

Prospective in vivo experiments to test the morphogenic power of increased fluid shear stress on ... more Prospective in vivo experiments to test the morphogenic power of increased fluid shear stress on collateral vessel growth (arteriogenesis) are rare. Therefore, the present study was designed to determine the arteriogenic potency of increased fluid shear stress and elucidate the underlying mechanism. Methods: Domestic pigs (n = 20) underwent bilateral proximal ligature of both superficial femoral arteries. At 1 week, a side-to-side anastomosis was created unilaterally between the distal femoral stump and the accompanying vein. Another week later, pressure and flow measurements in presence and absence of reactive hyperemia were performed to determine the fractional collateral flow (FCF). Quantitative arterial angiography was utilized for morphometric analysis of the collateral vessels. Subsequently, the vessels were excised and confocal immunohistochemistry (PCNA, eNOS, a-actin, lectin), as well as 2D-PAGE, differential expression analysis and Northern-blotting for destrin, cofilin-1, cofilin-2 and transgelin-2 was performed. Results: The number and size of collateral vessels was significantly increased in the shunted (S) as compared to the non-shunted (C) limb (p < 0,001; t-test). The mean fractional collateral flow was also significantly elevated (p<0,01). Immunohistochemistry confirmed a large number of PCNA-positive smooth muscle cells and endothelial cells and increased expression of lectin. eNOS expression was increased in collaterals, irrespective av-shunting. Cofilin-1, cofilin2, transgelin-2 and destrin displayed the highest degree of differential regulation in (S). Conclusions: Elevated shear stress is probably the most important physical molding force of arteriogenesis. Restart of the cell cycle of endothelial and smooth muscle cells and cytoskeletal re-arrangement of actin filaments are the key mechanisms that catalyze increased mobility during outward remodeling.

Research paper thumbnail of Treatment planning in patients with PAOD:Comparison of CE-MRA employing a dedicated peripheral MRA coil and high dose single volume contrast material application with i.a. DSA

EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, 2005

To evaluate whether contrast enhanced MRA (CE-MRA), including a dedicated MRA coil and a high dos... more To evaluate whether contrast enhanced MRA (CE-MRA), including a dedicated MRA coil and a high dose of contrast material, correlates to i.a. digital subtraction angiography (DSA) when used for treatment planning in patients with peripheral arterial obstructive disease (PAOD). A retrospective CE-MRA and i.a. DSA comparison was used to evaluate 2200 vessel segments with stenosis or occlusion in the pelvic or lower extremity arteries in 100 patients. A 1.5T MR unit (Magnetom Symphony Quantum, Siemens) employing a peripheral angiography array surface coil and automatic table movement was used. The interventional approach was planned according to both CE-MRA and DSA findings. Visual material was blinded and reviewed by two experienced radiologists.In 98.95% (Observer 1) and 98.1% (Observer 2) CE-MRA revealed an exact correlation of the grade as well as length of stenosis compared to DSA. The sensitivity was 100% and 95.3% for observers 1 and 2 and its specificity 98.3% and 100%, respectiv...

Research paper thumbnail of Hemmung von Allotransplantatabstoßung nach Photodynamischer Therapie Biologischer Gefäßprothesen

Chirurgisches Forum ’96 fur experimentelle und klinische Forschung, 1996

Autologe Arterien- und Venentransplantate gehoren zum unverzichtbaren Instrumentarium des Herz- u... more Autologe Arterien- und Venentransplantate gehoren zum unverzichtbaren Instrumentarium des Herz- und Gefaschirurgen. Da gegenwartig keine zufriedenstellenden synthetischen Prothesen fur kleinkalibrige Gefase (Durchmesser < 6 mm) existieren und autologe Arterien und Venen nur in begrenztem Umfang zur Verfugung stehen, besteht seit kurzem ein wiedererwachtes Interesse an der Transplantation allogener Gefase [1]. Biologische Gefasprothesen besitzen neben uberlegener biomechanischer Eigenschaften, eine vergleichsweise hohe Infektresistenz und gestatten eine schnellere und vollstandigere Reendothelialisierung im Vergleich zu synthetischen Ersatzmaterialien. Eine breite Anwendung biologischer Gefasprothesen wurde bisher jedoch durch die erhohte Inzidenz von Aneurysmabildung aufgrund einer chronischen Abstosungsreaktion verhindert [2]. Die Immunisierung des Empfangers geht dabei in erster Linie von glatten Muskelzellen aus der Media des Transplantates aus [3]. Fur die Funktion als Blutleiter sind diese Zellen jedoch nur von untergeordneter Bedeutung.

Research paper thumbnail of Anlage nativer arteriovenöser Zugänge

Der Chirurg, 2012

The epidemically increasing number of diabetics is resulting in an increasing number of patients ... more The epidemically increasing number of diabetics is resulting in an increasing number of patients with end-stage renal failure who, furthermore, show a high degree of co-morbidity. An increasingly longer survival time with dialysis also means that the group of patients requiring functional dialysis access is continuously growing. The autologous arteriovenous fistula with its high function and low complication rate is the best access form, and should be provided to as many of those patients requiring dialysis as possible. This article discusses the timing of dialysis access, the importance of the medical history and the physical examination, preoperative investigation of the prospective fistula vein, the possibilities of anastomosis, maturation of the fistula and long-term results.

Research paper thumbnail of Immunosuppressive aortic allografts treatment of

Research paper thumbnail of Use of time resolved 3D ultrasound data for the determination of the anisotropic elastic properties of the human aorta

Ultraschall in der Medizin - European Journal of Ultrasound, 2013

Purpose: Over last two decades computational methods for the analysis of the biomechanics of the ... more Purpose: Over last two decades computational methods for the analysis of the biomechanics of the vascular system have been developed, aiming at a better understanding of its physiology and pathophysiology and at clinical use as a tool for diagnosis and risk prediction of vascular diseases such as aortic aneurysms or plaque rupture. However, the benefit of such studies is currently limited by the lack of information on the patient specific material properties. In this work we employ blood pressure measurements and 3D ultrasound speckle tracking imaging to acquire the time resolved 3D displacement field of the abdominal aortic wall during blood pressure induced deformation in healthy volunteers. An inverse Finite Element Updating Method is applied to these data to determine the anisotropic hyperelastic mechanical properties of the abdominal aorta in vivo. Material and methods: Time resolved 3D ultrasound image data of abdominal aortic segments were acquired by use of a customized commercial real time 3D-echocardiography system (Artida, Toshiba). 3D speckle tracking of the full 4D data sets was performed using the algorithm implemented in the ACP-software. The spatially and temporally resolved strain fields resulting from the measurements or from a simulation of systolic pressure loading are compared to identify the parameters of a material model for arterial walls. Results: Spatially and temporally resolved strain fields of the abdominal aorta of healthy volunteers were calculated from 3D ultrasound data. These data were successfully used to identify the material properties of arterial walls in vivo. Conclusion: Recently, several approaches of constitutive parameter identification based on full-field measurements of displacement and strain fields have been presented. In this paper we present the application of such a method to in vivo full field displacement data of human aortas. This can be used to develop new tools for the diagnosis of vascular pathologies.

Research paper thumbnail of Recanalization results after carotid stent placement

AJNR. American journal of neuroradiology, 2002

The details of stent reconstruction in the vascular lumen and of the adaptation of carotid stents... more The details of stent reconstruction in the vascular lumen and of the adaptation of carotid stents, the vessel wall, and the vascular anatomy are only occasionally reported. The purpose of this study was to determine the immediate and longer-term anatomic results after implantation of self-expanding carotid stents. In a retrospective study, pre- and postprocedural angiograms and duplex sonograms from 40 consecutive carotid stent procedures in 39 patients (22 men, 17 women; mean age, 67 years; age range, 53-84 years) with high-grade (> or =70 %) internal carotid artery (ICA) stenoses were evaluated to assess the expansion of the vascular lumen, apposition of the stent, and geometric changes in the ICA after the implantation of rolling-membrane and carotid Wallstents (n = 22) or Easy Wallstents (n = 18). Optimal widening of the lumen and apposition of the stent were achieved in 11 (28%) of 40 arteries. Residual stenoses (n = 16), free stent filaments not attached to the vessel wall ...

Research paper thumbnail of Ultrasound Screening for Abdominal Aortic Aneurysm in the Emergency Department in an Asymptomatic Patient Population

Annals of Emergency Medicine, 2005

Research paper thumbnail of Quiescent-Interval Slice Selective Magnetic Resonance Angiography for Abdominal Aortic Aneurysm Treatment Planning

Journal of Endovascular Therapy, 2021

Purpose Diagnostic imaging of Abdominal aortic aneurysm (AAA) almost exclusively employs CT angio... more Purpose Diagnostic imaging of Abdominal aortic aneurysm (AAA) almost exclusively employs CT angiography (CTA) involving X-ray exposure and contrast medium that may harm some patients. Quiescent-Interval Slice Selective MR (QISS-MR) depicts vascular anatomy without radiation or contrast medium. The diagnostic quality of QISS-MRA and CTA were compared in regard to length and diameter measurements in AAA patients. Suitability of QISS-MRA for AAA treatment planning was evaluated. Materials and Methods The details of 30 patients with AAA who received both a QISS-MR and CTA for a known infrarenal AAA were obtained retrospectively that was approved by the local research ethics board. Two observers analyzed each dataset in terms of image quality and determined lumen diameter and length of 15 vessel segments. Results Highly accurate agreement between the diagnostic scores from the two observers was achieved. There was no significant difference between CTA and QISS-MRA for all 15 measured ves...

Research paper thumbnail of One-Year Results of First-Line Treatment Strategies in Patients With Critical Limb Ischemia (CRITISCH Registry)

Journal of Endovascular Therapy, 2018

Purpose: To examine the outcomes of all first-line strategies for the treatment of critical limb ... more Purpose: To examine the outcomes of all first-line strategies for the treatment of critical limb ischemia (CLI), identify factors that influenced the treatment choice, and determine the risk of amputation or death after each treatment. Methods: CRITISCH ( ClinicalTrials.gov identifier NCT01877252) is a multicenter, national, prospective registry evaluating all available treatment strategies applied in 1200 consecutive CLI patients in 27 vascular centers in Germany. The recruitment started in January 2013 and was completed in September 2014. Treatment options were endovascular revascularization (642, 53.5%), bypass surgery (284, 23.7%), femoral artery patchplasty (126, 10.5%) with or without concomitant peripheral intervention, conservative treatment (118, 9.8%), and primary major amputation (30, 2.5%). The primary endpoint of this study was amputation-free survival (AFS). The Society of Vascular Surgery’s suggested objective performance goal (OPG) for AFS (71%) was used as the effec...

Research paper thumbnail of The endovascular performance spectrum of vascular surgery departments in Germany

Gefässchirurgie, 2016

The endovascular performance spectrum of vascular surgery departments in Germany. Results of an o... more The endovascular performance spectrum of vascular surgery departments in Germany. Results of an online survey among senior department physicians Abstract Aim. To survey the scope of vascular surgery services in Germany. Method. A total of 308 senior German vascular surgeons received a 19-point questionnaire pertaining to department structure and scope of services. Of these surgeons 223 replied between

Research paper thumbnail of Das endovaskuläre Leistungsspektrum deutscher gefäßchirurgischer Abteilungen

Gefässchirurgie, 2016

The endovascular performance spectrum of vascular surgery departments in Germany. Results of an o... more The endovascular performance spectrum of vascular surgery departments in Germany. Results of an online survey among senior department physicians Abstract Aim. To survey the scope of vascular surgery services in Germany. Method. A total of 308 senior German vascular surgeons received a 19-point questionnaire pertaining to department structure and scope of services. Of these surgeons 223 replied between

Research paper thumbnail of Lower extremity arterial revascularization using conditioned small-diameter great saphenous vein

Journal of Vascular Surgery, 2016

Objective: This study was conducted to determine whether it was feasible to increase the diameter... more Objective: This study was conducted to determine whether it was feasible to increase the diameter of smaller great saphenous veins (GSVs) in preparation for possible bypass and whether such a conditioned conduit could be used with reasonable patency. Methods: Twenty-five patients (26 cases: 24 peripheral arterial occlusive disease, 2 popliteal aneurysms) with GSV diameters between 2 and 3 mm underwent in situ GSV valvulotomy and were observed for 3 months. After GSV dilation to >3 mm for below-knee revascularization and >3.5 mm for above-knee revascularization, arterial bypass surgery was performed with the valvulotomized GSV. Results: Adequate GSV diameter was reached in 20 cases (77%). Arterial bypass surgery using valvulotomized GSV was performed an average 131 days (range, 64-373 days) after valvulotomy in 16 patients (61.5%). No deaths, amputations, or aneurysms occurred 2 years after surgery. At 1 and 2 years, primary patency was 81% 6 9.8% and 69% 6 11.8%, respectively, and secondary patency was 87% 6 8.3% and 75% 6 11%, respectively. Conclusions: Valvulotomy can be used to expand small-diameter GSV for lower extremity arterial bypass.

Research paper thumbnail of Arteriogenesis and Therapeutic Neovascularization

Bad Nauheim, where she started to decipher the molecular mechanisms of arteriogenesis. After a sh... more Bad Nauheim, where she started to decipher the molecular mechanisms of arteriogenesis. After a short detour on stem cells, she again focused on arteriogenesis, becoming a leading expert in the field. By using a peripheral model of arteriogenesis, she demonstrated that collateral artery growth is a matter of innate immunity, and presented a blueprint of sterile inflammation, which is locally triggered by extracellular RNA.

Research paper thumbnail of Dacron-Ummantelung autologer Venenbypasses – Erste klinische Erfahrungen mit Provena®

Einleitung: Autologe Vena saphena magna ist Gold-Standard für Gefäßrekonstruktionen unterhalb des... more Einleitung: Autologe Vena saphena magna ist Gold-Standard für Gefäßrekonstruktionen unterhalb des Leistenbandes. Bei variköser Degeneration muss auf dieses überlegene Bypassmaterial jedoch verzichtet werden. Die vorliegende multizentrische Pilotstudie wurde durchgeführt,[for full text, please go to the a.m. URL]

Research paper thumbnail of Editorial Note for Journal of Vascular Medicine and Surgery

Journal of Vascular Medicine & Surgery, 2020

I am delighted to introduce the Journal of Vascular Medicine & Surgery (JVMS) a rapid peer review... more I am delighted to introduce the Journal of Vascular Medicine & Surgery (JVMS) a rapid peer reviewed journal which is a valuable source of information for scholars, researchers, professionals, and students, providing in-depth perspectives on intriguing contemporary topics of Vascular Medicine. Built on an ethos of openness, we are passionate about working with the global academic community to promote open scholarly research to the world. I am pleased to announce that, 3 issues of the 8 th Edition were published online well within the time and the print issues were also brought out and dispatched within 30 days of publishing the issue online during the year of 2020. The major objective of JVMS is to publish up-to-date, high-quality and original research papers alongside relevant and insightful reviews. The Journal aims to flourish and to maintain the standards in Vascular Medicine research and practices, providing an excellent platform and opportunity to present evidence based researc...

Research paper thumbnail of Pflegepersonalausstattung des Krankenhauses und Patientenoutcome

Research paper thumbnail of „Dem Nachwuchs verpflichtet“

Research paper thumbnail of Panvaskuläre Medizin – Professionalität, Perfektion und Vision

Research paper thumbnail of Gefäßchirurgie

Allgemein- und Viszeralchirurgie II - Spezielle Operative Techniken, 2015

Research paper thumbnail of Stimulation des Aktin-Metabolismus ist ein Schlüsselmechanismus des Kollateralwachstums nach Gefäßverschluss - Bedeutung einer permanenten Erhöhung der longitudinalen Schubspannung

Deutsche Gesellschaft für Chirurgie, 2004

Prospective in vivo experiments to test the morphogenic power of increased fluid shear stress on ... more Prospective in vivo experiments to test the morphogenic power of increased fluid shear stress on collateral vessel growth (arteriogenesis) are rare. Therefore, the present study was designed to determine the arteriogenic potency of increased fluid shear stress and elucidate the underlying mechanism. Methods: Domestic pigs (n = 20) underwent bilateral proximal ligature of both superficial femoral arteries. At 1 week, a side-to-side anastomosis was created unilaterally between the distal femoral stump and the accompanying vein. Another week later, pressure and flow measurements in presence and absence of reactive hyperemia were performed to determine the fractional collateral flow (FCF). Quantitative arterial angiography was utilized for morphometric analysis of the collateral vessels. Subsequently, the vessels were excised and confocal immunohistochemistry (PCNA, eNOS, a-actin, lectin), as well as 2D-PAGE, differential expression analysis and Northern-blotting for destrin, cofilin-1, cofilin-2 and transgelin-2 was performed. Results: The number and size of collateral vessels was significantly increased in the shunted (S) as compared to the non-shunted (C) limb (p < 0,001; t-test). The mean fractional collateral flow was also significantly elevated (p<0,01). Immunohistochemistry confirmed a large number of PCNA-positive smooth muscle cells and endothelial cells and increased expression of lectin. eNOS expression was increased in collaterals, irrespective av-shunting. Cofilin-1, cofilin2, transgelin-2 and destrin displayed the highest degree of differential regulation in (S). Conclusions: Elevated shear stress is probably the most important physical molding force of arteriogenesis. Restart of the cell cycle of endothelial and smooth muscle cells and cytoskeletal re-arrangement of actin filaments are the key mechanisms that catalyze increased mobility during outward remodeling.

Research paper thumbnail of Treatment planning in patients with PAOD:Comparison of CE-MRA employing a dedicated peripheral MRA coil and high dose single volume contrast material application with i.a. DSA

EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, 2005

To evaluate whether contrast enhanced MRA (CE-MRA), including a dedicated MRA coil and a high dos... more To evaluate whether contrast enhanced MRA (CE-MRA), including a dedicated MRA coil and a high dose of contrast material, correlates to i.a. digital subtraction angiography (DSA) when used for treatment planning in patients with peripheral arterial obstructive disease (PAOD). A retrospective CE-MRA and i.a. DSA comparison was used to evaluate 2200 vessel segments with stenosis or occlusion in the pelvic or lower extremity arteries in 100 patients. A 1.5T MR unit (Magnetom Symphony Quantum, Siemens) employing a peripheral angiography array surface coil and automatic table movement was used. The interventional approach was planned according to both CE-MRA and DSA findings. Visual material was blinded and reviewed by two experienced radiologists.In 98.95% (Observer 1) and 98.1% (Observer 2) CE-MRA revealed an exact correlation of the grade as well as length of stenosis compared to DSA. The sensitivity was 100% and 95.3% for observers 1 and 2 and its specificity 98.3% and 100%, respectiv...

Research paper thumbnail of Hemmung von Allotransplantatabstoßung nach Photodynamischer Therapie Biologischer Gefäßprothesen

Chirurgisches Forum ’96 fur experimentelle und klinische Forschung, 1996

Autologe Arterien- und Venentransplantate gehoren zum unverzichtbaren Instrumentarium des Herz- u... more Autologe Arterien- und Venentransplantate gehoren zum unverzichtbaren Instrumentarium des Herz- und Gefaschirurgen. Da gegenwartig keine zufriedenstellenden synthetischen Prothesen fur kleinkalibrige Gefase (Durchmesser < 6 mm) existieren und autologe Arterien und Venen nur in begrenztem Umfang zur Verfugung stehen, besteht seit kurzem ein wiedererwachtes Interesse an der Transplantation allogener Gefase [1]. Biologische Gefasprothesen besitzen neben uberlegener biomechanischer Eigenschaften, eine vergleichsweise hohe Infektresistenz und gestatten eine schnellere und vollstandigere Reendothelialisierung im Vergleich zu synthetischen Ersatzmaterialien. Eine breite Anwendung biologischer Gefasprothesen wurde bisher jedoch durch die erhohte Inzidenz von Aneurysmabildung aufgrund einer chronischen Abstosungsreaktion verhindert [2]. Die Immunisierung des Empfangers geht dabei in erster Linie von glatten Muskelzellen aus der Media des Transplantates aus [3]. Fur die Funktion als Blutleiter sind diese Zellen jedoch nur von untergeordneter Bedeutung.

Research paper thumbnail of Anlage nativer arteriovenöser Zugänge

Der Chirurg, 2012

The epidemically increasing number of diabetics is resulting in an increasing number of patients ... more The epidemically increasing number of diabetics is resulting in an increasing number of patients with end-stage renal failure who, furthermore, show a high degree of co-morbidity. An increasingly longer survival time with dialysis also means that the group of patients requiring functional dialysis access is continuously growing. The autologous arteriovenous fistula with its high function and low complication rate is the best access form, and should be provided to as many of those patients requiring dialysis as possible. This article discusses the timing of dialysis access, the importance of the medical history and the physical examination, preoperative investigation of the prospective fistula vein, the possibilities of anastomosis, maturation of the fistula and long-term results.

Research paper thumbnail of Immunosuppressive aortic allografts treatment of

Research paper thumbnail of Use of time resolved 3D ultrasound data for the determination of the anisotropic elastic properties of the human aorta

Ultraschall in der Medizin - European Journal of Ultrasound, 2013

Purpose: Over last two decades computational methods for the analysis of the biomechanics of the ... more Purpose: Over last two decades computational methods for the analysis of the biomechanics of the vascular system have been developed, aiming at a better understanding of its physiology and pathophysiology and at clinical use as a tool for diagnosis and risk prediction of vascular diseases such as aortic aneurysms or plaque rupture. However, the benefit of such studies is currently limited by the lack of information on the patient specific material properties. In this work we employ blood pressure measurements and 3D ultrasound speckle tracking imaging to acquire the time resolved 3D displacement field of the abdominal aortic wall during blood pressure induced deformation in healthy volunteers. An inverse Finite Element Updating Method is applied to these data to determine the anisotropic hyperelastic mechanical properties of the abdominal aorta in vivo. Material and methods: Time resolved 3D ultrasound image data of abdominal aortic segments were acquired by use of a customized commercial real time 3D-echocardiography system (Artida, Toshiba). 3D speckle tracking of the full 4D data sets was performed using the algorithm implemented in the ACP-software. The spatially and temporally resolved strain fields resulting from the measurements or from a simulation of systolic pressure loading are compared to identify the parameters of a material model for arterial walls. Results: Spatially and temporally resolved strain fields of the abdominal aorta of healthy volunteers were calculated from 3D ultrasound data. These data were successfully used to identify the material properties of arterial walls in vivo. Conclusion: Recently, several approaches of constitutive parameter identification based on full-field measurements of displacement and strain fields have been presented. In this paper we present the application of such a method to in vivo full field displacement data of human aortas. This can be used to develop new tools for the diagnosis of vascular pathologies.

Research paper thumbnail of Recanalization results after carotid stent placement

AJNR. American journal of neuroradiology, 2002

The details of stent reconstruction in the vascular lumen and of the adaptation of carotid stents... more The details of stent reconstruction in the vascular lumen and of the adaptation of carotid stents, the vessel wall, and the vascular anatomy are only occasionally reported. The purpose of this study was to determine the immediate and longer-term anatomic results after implantation of self-expanding carotid stents. In a retrospective study, pre- and postprocedural angiograms and duplex sonograms from 40 consecutive carotid stent procedures in 39 patients (22 men, 17 women; mean age, 67 years; age range, 53-84 years) with high-grade (> or =70 %) internal carotid artery (ICA) stenoses were evaluated to assess the expansion of the vascular lumen, apposition of the stent, and geometric changes in the ICA after the implantation of rolling-membrane and carotid Wallstents (n = 22) or Easy Wallstents (n = 18). Optimal widening of the lumen and apposition of the stent were achieved in 11 (28%) of 40 arteries. Residual stenoses (n = 16), free stent filaments not attached to the vessel wall ...

Research paper thumbnail of Ultrasound Screening for Abdominal Aortic Aneurysm in the Emergency Department in an Asymptomatic Patient Population

Annals of Emergency Medicine, 2005

Research paper thumbnail of Quiescent-Interval Slice Selective Magnetic Resonance Angiography for Abdominal Aortic Aneurysm Treatment Planning

Journal of Endovascular Therapy, 2021

Purpose Diagnostic imaging of Abdominal aortic aneurysm (AAA) almost exclusively employs CT angio... more Purpose Diagnostic imaging of Abdominal aortic aneurysm (AAA) almost exclusively employs CT angiography (CTA) involving X-ray exposure and contrast medium that may harm some patients. Quiescent-Interval Slice Selective MR (QISS-MR) depicts vascular anatomy without radiation or contrast medium. The diagnostic quality of QISS-MRA and CTA were compared in regard to length and diameter measurements in AAA patients. Suitability of QISS-MRA for AAA treatment planning was evaluated. Materials and Methods The details of 30 patients with AAA who received both a QISS-MR and CTA for a known infrarenal AAA were obtained retrospectively that was approved by the local research ethics board. Two observers analyzed each dataset in terms of image quality and determined lumen diameter and length of 15 vessel segments. Results Highly accurate agreement between the diagnostic scores from the two observers was achieved. There was no significant difference between CTA and QISS-MRA for all 15 measured ves...

Research paper thumbnail of One-Year Results of First-Line Treatment Strategies in Patients With Critical Limb Ischemia (CRITISCH Registry)

Journal of Endovascular Therapy, 2018

Purpose: To examine the outcomes of all first-line strategies for the treatment of critical limb ... more Purpose: To examine the outcomes of all first-line strategies for the treatment of critical limb ischemia (CLI), identify factors that influenced the treatment choice, and determine the risk of amputation or death after each treatment. Methods: CRITISCH ( ClinicalTrials.gov identifier NCT01877252) is a multicenter, national, prospective registry evaluating all available treatment strategies applied in 1200 consecutive CLI patients in 27 vascular centers in Germany. The recruitment started in January 2013 and was completed in September 2014. Treatment options were endovascular revascularization (642, 53.5%), bypass surgery (284, 23.7%), femoral artery patchplasty (126, 10.5%) with or without concomitant peripheral intervention, conservative treatment (118, 9.8%), and primary major amputation (30, 2.5%). The primary endpoint of this study was amputation-free survival (AFS). The Society of Vascular Surgery’s suggested objective performance goal (OPG) for AFS (71%) was used as the effec...

Research paper thumbnail of The endovascular performance spectrum of vascular surgery departments in Germany

Gefässchirurgie, 2016

The endovascular performance spectrum of vascular surgery departments in Germany. Results of an o... more The endovascular performance spectrum of vascular surgery departments in Germany. Results of an online survey among senior department physicians Abstract Aim. To survey the scope of vascular surgery services in Germany. Method. A total of 308 senior German vascular surgeons received a 19-point questionnaire pertaining to department structure and scope of services. Of these surgeons 223 replied between

Research paper thumbnail of Das endovaskuläre Leistungsspektrum deutscher gefäßchirurgischer Abteilungen

Gefässchirurgie, 2016

The endovascular performance spectrum of vascular surgery departments in Germany. Results of an o... more The endovascular performance spectrum of vascular surgery departments in Germany. Results of an online survey among senior department physicians Abstract Aim. To survey the scope of vascular surgery services in Germany. Method. A total of 308 senior German vascular surgeons received a 19-point questionnaire pertaining to department structure and scope of services. Of these surgeons 223 replied between

Research paper thumbnail of Lower extremity arterial revascularization using conditioned small-diameter great saphenous vein

Journal of Vascular Surgery, 2016

Objective: This study was conducted to determine whether it was feasible to increase the diameter... more Objective: This study was conducted to determine whether it was feasible to increase the diameter of smaller great saphenous veins (GSVs) in preparation for possible bypass and whether such a conditioned conduit could be used with reasonable patency. Methods: Twenty-five patients (26 cases: 24 peripheral arterial occlusive disease, 2 popliteal aneurysms) with GSV diameters between 2 and 3 mm underwent in situ GSV valvulotomy and were observed for 3 months. After GSV dilation to >3 mm for below-knee revascularization and >3.5 mm for above-knee revascularization, arterial bypass surgery was performed with the valvulotomized GSV. Results: Adequate GSV diameter was reached in 20 cases (77%). Arterial bypass surgery using valvulotomized GSV was performed an average 131 days (range, 64-373 days) after valvulotomy in 16 patients (61.5%). No deaths, amputations, or aneurysms occurred 2 years after surgery. At 1 and 2 years, primary patency was 81% 6 9.8% and 69% 6 11.8%, respectively, and secondary patency was 87% 6 8.3% and 75% 6 11%, respectively. Conclusions: Valvulotomy can be used to expand small-diameter GSV for lower extremity arterial bypass.