Biomedical subjects

M Schoder

Publications and source records attributed to M Schoder.

At least 19 recordsLinked to original sources

PubMed2006

[PTA and stent placement distal to the superficial femoral artery].

Although angioplasty and stent applications in the iliac vessels and the superficial femoral artery have become routine procedures, their usefulness for the treatment of lesions of the popliteal artery and the lower leg arteries is still under discussion. For the popliteal artery, limitations are mainly due to the high mechanical stress in this area, causing high traction forces. Moreover, beyond the occlusive atherosclerotic changes, specific pathological entities such as aneurysms, emboli, entrapment syndromes, and cystic adventitial disease have to be differentiated. There is hope that the development of innovative stent designs with high flexibility might overcome the limitations. For lesions of the lower leg arteries treatment with percutaneous transluminal angioplasty (PTA) has become the method of choice. However, stent designs as used for cardiac interventions have been adapted for their application below the knee, and first encouraging results may help to justify their broad use in the future. Regarding PTA, innovative equipment and techniques for the treatment of arterial lesions below the knee include dedicated, long, and very flexible balloons, cutting balloon cryoplasty, and laser angioplasty. Regarding stents, bare metal stents, stents with passive or active coatings, and bioabsorbable stents have all been successfully used.

Angioplasty, Balloon↗

PubMed2006

Treatment of an acute type B dissection with an intramural haematoma in the ascending aorta by percutaneous endovascular stent-graft placement.

Acute type B dissections accompanied by an intramural haematoma in the ascending aorta are rare. However, progression of the intramural haematoma in the ascending aorta poses risks for the patients, which are similar to those of type A dissections, including pericardial effusions and consecutive tamponade. To date, no clear treatment guidelines exist for these patients. We report on successful percutaneous endovascular stent-graft treatment of an acute type B dissection accompanied by an intramural haematoma in the ascending aorta as primary and sole form of treatment.

Aged↗

PubMed2005

Mid-term results of conservative, conventional and endovascular treatment for acute traumatic aortic lesions.

BACKGROUND: To analyze our results after conservative, conventional and endovascular treatment for acute traumatic aortic lesions during the last decade. METHODS: From June 1993 to September 2004, a total of 19 patients with traumatic aortic lesions were referred to our department. All patients sustained injuries from blunt deceleration trauma. In hemodynamically stable patients, initial evaluation was by multi-slice CT scan. The diagnosis of traumatic aortic injury was confirmed and an individual treatment strategy was determined. In hemodynamically unstable patients, emergency thoracotomy was performed. RESULTS: An emergency thoracotomy was performed in seven (37%) patients. Mortality in this group was 100%. In the remaining group of 12 (63%) patients without hemodynamic instability at time of admission, in-hospital mortality was 0%. Treatment was surgical in five patients (26%), endovascular in five (26%) and conservative in two patients (11%). Mean follow-up was 63 months (5-108 months). No patient died during follow-up. In patients treated by endovascular stent-graft placement no signs of endoleaks could be detected. CONCLUSIONS: Hemodynamic stability and an individual treatment strategy are prerequisites for survival of acute traumatic aortic lesions. Endovascular stent-graft placement has emerged as an innovative and minimally invasive therapeutic option in this polytraumatic high-risk patient cohort.

Adult↗

PubMed2005

Successful type II endoleak closure by subclavian-to-carotid artery transposition after stent-graft placement of a distal aortic arch aneurysm.

Endovascular stent-graft placement has become a safe and effective treatment modality for various diseases of the distal aortic arch as well as of the descending aorta. However, its effectiveness may be limited by various kinds of endoleaks resulting in persistent or recurrent perfusion of the aneurysm sac. Subsequently, systemic pressurization leads to expansion of the aneurysm sac, exposing the patient to a recurrent risk of aneurysm rupture. We report on the case of a 57-year-old male who underwent emergency stent-graft placement in March 2001 due to a contained rupture of a distal aortic arch aneurysm involving the origin of the left subclavian artery. Due to the emergency condition, a subclavian-to-carotid artery transposition had not been performed prior to stent-graft placement. During follow-up the patient developed a type II endoleak originating from the left subclavian artery with consecutive enlargement of the aneurysm sac. The endoleak was successfully treated by subclavian-to-carotid artery transposition.

Aortic Aneurysm, Thoracic↗

PubMed2004

The role of Chlamydia pneumoniae in human aortic disease-a hypothesis revisited.

BACKGROUND: The role of Chlamydia pneumoniae in the pathogenesis of aortic aneurysm is controversial. We investigated the presence of C. pneumoniae in tissue samples excised from patients and controls. METHODS: Aortic wall specimens were obtained from 17 patients with acute Stanford type A aortic dissection, 25 patients with thoracic aortic aneurysms (TAA) and 23 patients with abdominal aortic aneurysms (AAA). Eighty-three tissue samples of 73 control patients free of aortic disease were obtained either at surgery or autopsy. The presence of Chlamydia subspecies DNA (sequences specific for all known Chlamydiaceae) and DNA of C. pneumoniae, C. trachomatis and C. psittaci were assessed by a validated highly sensitive and specific real time polymerase chain reaction (PCR) analysis. Atherosclerotic risk factors were assessed in all patients. RESULTS: We failed to detect C. pneumoniae and C. psittaci-DNA in any of the 148 vessel specimens. C. trachomatis-DNA was detected in 1/65 patients and in none of 83 controls (P=0.43). Chlamydia subspecies DNA was found in samples of eight cases and in one control (P=0.01), however, no significant differences were found between the subgroups aortic dissection (P=0.09), TAA (P=0.99) and AAA (P=0.15) and respective controls. CONCLUSIONS: C. pneumoniae does not play a clinically relevant role in acute and chronic aortic disease. The impact of other organisms of the family Chlamydiaceae needs further evaluation.

Aged↗

PubMed2002

Endoluminal stent-graft placement in patients with acute aortic dissection type B.

OBJECTIVES: This study was performed to evaluate the feasibility, safety and effectiveness of endovascular stent-grafting in treating Stanford type B acute aortic dissection. We describe our first clinical experiences and initial results with stent-grafting across the primary entry tear in patients with acute aortic dissection type B. METHODS: Between March 2000 and August 2001, nine patients with acute type B dissection were treated endoluminally by stent-graft implantation. There were seven male and two female patients with a mean age of 63 years (between 48 and 85 years). In all nine patients aortic dissection was diagnosed by multislice computed tomography (CT) angiography. All nine patients had a maximal aortic diameter of 5.5 cm or more and recurrent pain, one patient showed hemoptysis. This patient with signs of a contained rupture was treated under emergency condition, the eight remaining patients were in hemodynamic stabile condition at the time of intervention. The GORE Excluder stent-graft system was used in eight patients (mean 1.8 stents/patient) and the TALENT stent-graft system in one patient, which were introduced transfemorally. RESULTS: The primary entry tear could be sealed successfully in all nine patients. Complete thrombosis of the false thoracic aortic lumen was obtained in two patients, in the remaining seven patients the false lumen was obliterated in the area of the thoracic aorta but perfused via re-entries in the abdominal region. No severe intraoperative complications occurred. One patient developed bilateral incomplete paraplegia with motor and sensory deficits affecting completely the right leg and partially the left leg, 14 h after intervention. A cerebrospinal fluid drainage was initiated by inserting a lumbar catheter. All nine patients, including the patient with the transient paraplegia, could be discharged from the hospital in excellent condition and without remaining neurologic deficits. Control CT scans showed a reduction of the false lumen from 2.34+/-0.58 to 0.7+/-0.44 cm and an increase of the true lumen from 1.56+/-0.5 to 4.10+/-0.6 cm in the thoracic aortic region. Mean ICU stay was 1.8 days, mean postoperative hospital stay was 7.6 days. CONCLUSIONS: Stent-grafting of acute type B dissections may represent a very effective and promising new method by closure of the primary entry tear, thereby minimizing the risk of rupture of the thoracic aorta and optimizing distal perfusion by decompression of the true lumen.

Aged↗

PubMed2001

Inferior mesenteric artery as outflow vessel in endoleaks after abdominal aortic stent-graft implantation: 36-month follow-up CT study.

The aim of this study was to determine the role of the inferior mesenteric artery (IMA) as an outflow vessel in endoleaks after abdominal aortic stent-graft implantation. Forty consecutive patients in whom abdominal aortic aneurysms (AAA) had been treated with stent-graft implantation were evaluated retrospectively. Spiral-CT examinations and angiographies up to 36 months after implantation were analyzed. In 29 (73%) of the 40 patients the IMA was perfused prior to implantation. In 5 (17%) of these 29 cases, the artery remained perfused after stent-graft insertion. In all 5 cases, endoleaks were detected; however, in none of these cases was the IMA the sole cause. In 3 of these 5 cases, angiography showed antegrade flow in the IMA. Implantation of extension stent grafts caused thrombosis of the aneurysmal sac and the IMA. There were no secondary endoleaks caused by the IMA at the 36-month follow-up examinations. The majority of IMAs which are patent prior to intervention occlude after successful stent-graft insertion. In cases with leaks and angiographically proven antegrade flow in the IMA, implantation of extension stent grafts is a therapeutic alternative to embolization. In this study, the IMA was not responsible for secondary endoleaks.

Aged↗

PubMed2001

Biocompatibility and performance of the Wallstent and several covered stents in a sheep iliac artery model.

PURPOSE: To compare the biocompatibility and performance of various stent-grafts to those of a bare stent in an ovine model with a subchronic (3 months) endpoint. MATERIALS AND METHODS: Three different types of stent-grafts (ePTFE/nitinol, n = 8; polyester/nitinol, n = 8; and polycarbonate urethane/cobalt-alloy, n = 8) and a bare stent as a control (Ni-Co-Ti-steel-alloy, n = 8) were implanted in the iliac arteries in eight female sheep. One type of each stent-graft was implanted per animal, two implants at each side. The implantation sites for each type varied from animal to animal. Angiographic control and intravascular ultrasound (IVUS) imaging were performed before and after implantation, after 2 months, and before explantation at 3 months and were used to characterize patency and to assess intimal hyperplasia. After 3 months, the implants were retrieved and subjected to histologic evaluation (after methacrylate embedding, cutting, and histologic staining) to characterize the biologic response. RESULTS: Implantation was technically successful in all procedures. At 2 and 3 months after implantation, all segments in which stents had been implanted were patent. Marked neointima formation was found in the polyester-covered stent-graft that showed significant luminal narrowing of 50%, compared to the ePTFE-covered (24%) and polycarbonate urethane-covered endoprostheses (22%), as well as the bare stent (Wallstent; 9%; P < .001). A minimal inflammatory vessel wall reaction was demonstrated for the polyester-covered and ePTFE-covered endoprostheses; the polycarbonate urethane-covered stent-graft's response was demonstrable but not significantly different from that of the Wallstent. At 3 months, the ePTFE-covered stent-graft showed incomplete (>90%) endothelial coverage; in the other endoprostheses, complete but partially immature endothelialization was found. CONCLUSION: All stent-grafts induced an inflammatory vessel wall reaction with neointimal hyperplasia. The polyester-covered endoprosthesis caused a marked reaction with 50% luminal stenosis. Endothelialization was retarded with the ePTFE-covered stent-graft. The bare stent performed best in regard to neointimal formation and caused the least inflammatory response.

Alloys↗

PubMed2001

[Interventions in infrainguinal bypass grafts].

The long-term success of infrainguinal bypass grafts depends on meticulous surgical technique and a periodic program of postoperative surveillance. Duplex scanning is the method of choice for the detection of stenotic lesions that threaten graft patency. As an alternative to surgery, PTA is gaining increasing acceptance for the treatment of non-recurrent, short, and single stenotic lesions, despite somewhat controversial opinions. The initial technical success rates for PTA were reported to be up to 100 %, and a 5-year primary assisted patency rate of up to 65 % has been achieved. Some authors favorize intra-arterial infusion of fibrinolytic agents for the treatment of bypass graft occlusion with technical success rates of up to 92 %. In addition to a reduced trauma compared to surgical thrombectomy, of the venous wall the advantage of thrombolytic therapy is clot lysis in run-off vessels, and uncovering of the stenotic lesions. This stenosis may then be treated by an endovascular or surgical approach.

Angiography↗

PubMed2001

Midterm durability of abdominal aortic aneurysm endograft repair: a word of caution.

PURPOSE: Endograft technology for abdominal aortic aneurysm (AAA) repair is being applied more liberally. There is little information about the midterm performance of these grafts. This study is focused on follow-up interventions after endograft repair for AAA. METHODS: Prospective follow-up analysis of a consecutive patient series (n = 173 patients) at a single center who underwent endovascular AAA repair up to 50 months after operation. Seventeen percent of the patients were regarded unfit for open surgery. Four types of commercially available grafts were used. The Society for Vascular Surgery/International Society for Cardiovascular Surgery guidelines were applied for endograft implantation and data preparation. RESULTS: In two patients, the procedure was converted to open surgery. In one procedure, emergency repair for iliac artery rupture was performed. The 30-day mortality rate was 2.8% (n = 5 patients). An early second procedure to correct type I endoleaks was necessary in 8 cases (4.6%; 3-10 days). The following midterm results were obtained: median follow-up of the 166 remaining patients was 18 months (range, 1-50 months); 50 additional procedures were necessary in 37 patients (22.3%) for the treatment of leaks (n = 45 interventions) or to maintain graft patency (n = 5 grafts; four patients with concomitant graft segment disconnection); and 46% of the reinterventions were performed within the first year of follow-up and 74% of the reinterventions were performed within the second year of follow-up. One patient died after emergency surgery for rupture as the result of a secondary endoleak at 1 year. Although seven interventions (14%) were performed for type II endoleak, no serious complications were related to patent sidebranches. There was no statistically significant difference between the need for maintenance in different graft configurations (tubular, bifurcated, aorto-uniiliac), or number of graft segments (1, 2, 3-4, > or = 5 segments). New generation grafts (after 1996) performed better than early generation grafts (P = 0.04, chi-squared test) with regard to endoleak development. CONCLUSION: Endograft repair for AAA is safe but, with current technology, not as durable as open repair. Our data suggest that the use of endograft repair for AAA is becoming safer as endograft design improves. Nevertheless in 26.6% of the patients, there is need for reintervention within midterm follow-up. Close follow-up is crucial because late leaks may develop after more than 2 years after the initial procedure. Endoluminal repair should therefore be applied with caution, strict indication, and only if a tight follow-up is warranted. These findings may also affect health care reimbursement policies.

Aged↗

PubMed2001

Creation of transjugular intrahepatic portosystemic shunts with stent-grafts: initial experiences with a polytetrafluoroethylene-covered nitinol endoprosthesis.

PURPOSE: To evaluate the safety and performance of a recently developed expanded polytetrafluoroethylene (ePTFE)-covered nitinol stent-graft to create transjugular intrahepatic portosystemic shunt (TIPS) in patients with portal hypertension and related complications. MATERIALS AND METHODS: The ePTFE-covered nitinol stent-graft was used to create TIPS in 16 patients with recurrent variceal bleeding (n = 13) or refractory ascites (n = 3). Follow-up was performed with duplex ultrasonography, clinical assessment, and venography at 6 months. Technical success and portosystemic pressure gradients (PPGs) before and after stent-graft implantation and at follow-up were assessed. Two patients died during follow-up. Histopathologic follow-up data were available for one patient at autopsy and for the other after liver transplantation. RESULTS: The implantation technical success rate was 100%. Mean (+/- SD) PPG was reduced from 24 mm Hg +/- 5 to 9 mm Hg +/- 2. Histopathologic analysis of the explanted endoprostheses revealed no inflammatory response or neointima formation. The venographic follow-up data available for 10 patients demonstrated 100% in-graft patency (mean follow-up, 289 days +/- 26). Revisions with implantation of a new ePTFE-covered nitinol stent-graft or another commercially available stent in 10 patients were necessary because of hepatic vein stenosis above the grafted portion and/or relative diameter mismatch causing TIPS dysfunction. CONCLUSION: The ePTFE-covered nitinol stent-graft was used successfully to create TIPS and has the potential to prolong TIPS patency upon complete coverage to the hepatocaval junction.

Adult↗

PubMed2001

Internal iliac artery embolization before endovascular repair of abdominal aortic aneurysms: frequency, efficacy, and clinical results.

OBJECTIVE: The aim of our study was to assess the frequency, efficacy, and incidence of adverse effects of internal iliac artery embolization. MATERIALS AND METHODS: Of 343 patients examined for stent-graft repair, 147 were suitable for endovascular treatment. Fifty-five patients underwent preprocedural embolization of the internal iliac artery either unilaterally (46 patients) or bilaterally (nine patients). Successful embolization was assessed angiographically and with helical CT follow-up examinations. Colonic ischemia was ruled out clinically or colonoscopically. Buttock claudication, and sexual dysfunction in men, were evaluated through a questionnaire. RESULTS: Embolization of the internal iliac artery increased by 16% the percentage of patients for whom endovascular repair was suitable. After successful embolization in all patients, routine CT follow-up examinations after a mean time of 16.7 months showed no evidence of endoleaks related to retrograde perfusion via embolized internal iliac arteries. Nevertheless, in all patients who had undergone embolization, a primary endoleak was detected in 43.4% at the first postoperative CT examination. None of our patients had evidence of colonic ischemia. Clinical follow-up data of 46 patients were available. Of these patients, mild to severe new onset buttock claudication was found in 13 (36.1%) of 36 patients with unilateral, and in eight (80%) of 10 patients with bilateral, internal iliac artery embolization (p = 0.03). Five (25%) of 20 men had an erectile dysfunction after the procedure. CONCLUSION: Embolization of the internal iliac artery is a safe and efficient procedure that increases the applicability for endovascular repair of aortoiliac aneurysms. However, buttock claudication and erectile dysfunction are a drawback in a substantial number of patients.

Aged↗

PubMed2001

[Acute peripheral arterial ischemia: diagnosis and interventional therapy].

Acute peripheral arterial ischaemia is characterized by a rapidly developing perfusion deficiency with potential necrosis of the involved extremity. In more than 90% an embolic or thromboembolic etiology is present. Differential diagnosis includes all other vascular disease entities. Digital subtraction angiography is the radiological modality of choice for diagnosis and interventional therapy. Prior to a planned local fibrinolytic therapy potential contraindications have to be excluded.

Acute Disease↗

PubMed2000

Glue embolization of a ruptured celiac trunk pseudoaneurysm via the gastroduodenal artery.

Percutaneous transcatheter embolization of splanchnic artery aneurysms is a minimally invasive and alternative therapy to conventional surgical intervention. Due to a high-grade stenosis at the origin of the celiac trunk, a retrograde approach to the celiac trunk pseudoaneurysm via the gastroduodenal artery was necessary. To prevent undesirable embolization into the peripheral left gastric artery initial occlusion of the central portion of the left gastric artery was performed with microcoils using a Tracker catheter. Complete occlusion of the celiac trunk itself and the short adjacent segments of the celiac artery was achieved by using a mixture of N-butyl-2-cyanoacrylate and ethiodized oil as the embolizing agent.

Aneurysm, False↗

PubMed1999

[PTA vs. stent in femoro-popliteal obstruction].

PURPOSE: To evaluate whether primary stenting is superior to balloon angioplasty (PTA) alone in the treatment of femoropopliteal obstructive disease. MATERIALS AND METHODS: Sixty-two patients, 24 female and 38 male, mean age 67 years (39-87) years, were randomized to PTA alone (n = 37) or balloon angioplasty followed by implantation of Palmaz stents (n = 33). Follow-up included clinical assessment, ankle-brachial index (ABI), color duplex ultrasound at 1, 3, 6 and 12 months after intervention and intravenous angiography at 6 or 12 months. RESULTS: We had four cases of primary PTA failures (10.8%) and no early (< 30 days) thrombosis compared to one primary stent failure (3.0%) and three early thromboses (9.0%) in the stent group. Cumulative primary angiographic patency rates (life-table analysis) for PTA alone were 82% and 72% (6 and 12 months, respectively) compared to 81% and 60% for primary stent placement. The secondary angiographic patency were 97% and 88% for PTA and 88% and 72% for stent implantation, respectively. However, there was no significant difference in patency rates. CONCLUSIONS: Despite fewer primary technical failures, mid-term angiographic and clinical patency were not improved by primary stent placement compared to PTA alone.

Adult↗

PubMed1999

Virchow-Robin spaces in childhood migraine.

Virchow-Robin spaces (VRS) are pia-lined extensions of the subarachnoid space which surround penetrating arteries as they enter the brain on its surface. Using high-resolution MRI, which shows small penetrating arteries, we studied a possible association of accentuated VRS in children with tension-type headache (TTH) or migraine. We studied 58 children aged 3-14 years (mean 10.8 years) with a clinical diagnosis of migraine (31) or TTH (27), who underwent cerebral MRI, and 30 headache-free patients of the same age (mean 10.2 years) and 30 adult migraineurs with postpubertal onset of symptoms, who served as controls. The images were reviewed for structural abnormalities in the regions of the small penetrating arteries. Accentuated VRS were found in 61% of the children with migrainous headaches and in 22% of children of those with TTH. Prominent VRS were seen in 27% of the control children and in only 13% of the adults. Small infarcts and gliosis were rare in children with or without headache, but were seen in 30% of the adult migraineurs. Our findings show that accentuated VRS are significantly more common in children with migraine than in those with TTH or headache-free controls. Detection of accentuated VRS may therefore enhance differential diagnosis of primary headaches in children, contributing to an improvement in management.

Adolescent↗

PubMed1997

[Pulmonary hypertension and cor pulmonale].

Pulmonary hypertension is a severe disorder of the pulmonary circulation and occurs in a variety of vascular and parenchymal lung diseases. It leads to volume and/or pressure overload of the right ventricle and finally to right heart failure. Pulmonary vascular diseases such as chronic pulmonary embolism cause a drastic increase in pulmonary vascular resistance, which results in extremely high pulmonary artery pressures that can even reach systemic levels. On the other hand, moderate pulmonary hypertension can also occur in chronic obstructive and restrictive lung diseases. For a long time, the diagnosis of pulmonary hypertension and cor pulmonale was based upon findings in echocardiography and right heart catheterization. Today modern imaging techniques allow the radiologist to assess right ventricular and pulmonary artery morphology and function. The application of spiral CT, electron-beam CT and MRT permits the diagnosis and differential diagnosis of pulmonary hypertension and also the evaluation and follow-up of underlying vascular or parenchymal lung disorders. In addition, quantification of right ventricular function and calculation of pulmonary hemodynamic parameters are possible.

Adult↗

PubMed1996

High frequency of EEG and MRI brain abnormalities in panic disorder.

The frequency and quality of brain abnormalities in panic disorder (PD) were assessed with magnetic resonance imaging (MRI). The use of electroencephalography (EEG) to detect PD patients with a high probability of morphologic brain abnormalities was also explored. Consecutive PD patients (n = 120) were screened with routine EEG examinations and were divided into the following subgroups on the basis of their EEG findings: patients with non-epileptic EEG abnormalities (EEG-A group, n = 28), matched patients with normal EEG results (EEG-N group, n = 28) and matched healthy controls (n = 28). PD patients showed a higher than expected rate of non-epileptic EEG abnormalities (29.2%; 35 of 120). EEG screening was effective in identifying patients with a high probability of morphologic brain abnormalities. MRI abnormalities were found in 60.7% of the EEG-A patients, 17.9% of the EEG-N patients, and only 3.6% of the controls. A high frequency of septo-hippocampal abnormalities was found. Further research should focus on attempts to subtype PD on the basis of neuroanatomic and functional brain abnormalities.

Adult↗