PubMed Health⌕ Search

Biomedical subjects

J Lammer

Publications and source records attributed to J Lammer.

At least 19 recordsLinked to original sources
PubMed2007

Plaque imaging of the internal carotid artery - correlation of B-flow imaging with histopathology.

BACKGROUND AND PURPOSE: The noninvasive identification of plaque types prone to cause symptomatic disease is of great interest to improve the effectiveness of surgical or interventional management. The purpose of the present prospective pilot study was to evaluate the association between the results of imaging-the novel sonography technique B-flow imaging (BFI), B-mode, and color Doppler imaging (CDI)-and histopathologic examination in the characterization of internal carotid artery (ICA) plaques. METHODS: Twenty-eight consecutive patients with high-grade internal carotid artery stenosis scheduled for carotid endarterectomy were included. BFI, B-mode, and CDI images were used to classify the plaques applying the standardized scores of Beletsky et al and the American Heart Association (AHA), to calculate the gray-scale median (GSM) and to detect potential ulcerations; histopathologic examination results of explanted plaques served as the "gold standard." RESULTS: Based on the classification of Beletsky et al, BFI and histopathologic examination results agreed in 21 (75%, kappa = 0.61, P < .001) patients, and the corresponding results for B-mode were 19 (68%, kappa = 0.52, P < .001) patients, respectively. Corresponding results for the AHA classification revealed inferior agreements for BFI (19 patients/68%, kappa = 0.38, P = .003) and B-mode (17 patients/61%, kappa = 0.25, P = .045). The median GSM for BFI and B-mode correlated significantly (r = 0.95, P < .001). The sensitivity of BFI for the detection of ulcerated plaques was 100% and the specificity was 95.8%; corresponding values for CDI were 100% and 92.7%, respectively. CONCLUSION: BFI and the combination of B-mode and CDI exhibit comparable results in the assessment of ICA plaque components and plaque ulceration as well as in the determination of GSM levels.

Aged↗
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

[Percutaneous radiofrequency ablation of liver cell carcinoma: a current overview].

In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.

Carcinoma, Hepatocellular↗
PubMed2004

[Three-dimensional digital rotation angiography for embolization therapy of uterine leiomyomas: first results].

PURPOSE: To evaluate three-dimensional rotational digital subtraction angiography (3D-RDSA) in the embolization of the uterine artery in the treatment of symptomatic uterine leiomyomas (fibroids). MATERIALS AND METHODS: Eight women with complex pelvic vessel anatomy caused by large fibroids were embolized using 3D-RDSA. The raw data were sent to an external workstation, and video files with a resolution of one image/3 degrees and a scan range of 180 degrees in a surface-shaded display mode were produced. The primary goal was to assess an image intensifier angulation for the optimal visualization of the origin of the uterine artery. In addition, the intervention parameters were compared with those of 48 patients with standard angiography. RESULTS: The analysis revealed no single angulation that can be recommended for standard angiography. No statistical differences were found between both groups concerning fluoroscopy time, dosage area product and amount of administered contrast medium (p > 0.05). CONCLUSION: It can be stated that 3D-RDSA is a feasible method that facilitates the catheterization of the uterine artery even in patients with complex pelvic vessel anatomy, with the potential to reduce the radiation exposure and the amount of administered contrast medium in future embolization therapy of symptomatic uterine fibroids.

Angiography↗
PubMed2003

The impact of endovascular stent grafting on reducing mortality rates after surgical treatment of abdominal aortic aneurysms.

OBJECTIVES: to investigate whether appropriate selection in patients with infrarenal abdominal aortic aneurysms (AAA) for transfemoral endovascular aneurysm management (TEAM) or open graft replacement (OGR) may decrease in-hospital mortality rates (MR). DESIGN: analysis of a clinical series over three periods in an university vascular center. Conclusions of the second period were drawn and prospectively applied in a third period and compared. METHODS: during the period 1989-1994 only OGR was available (n=170). In the interval 1995-2000 either OGR or TEAM were carried out (n=454). During the period 01/2001-07/2002 the conclusions concerning selection of treatment modality were drawn and prospectively applied in 132 consecutive patients. MR were recorded and possible significant differences were checked. RESULTS: during the first period MR was 6.5%. Overall MR decreased to 3.7% in the second interval. Overall MR of the last period was improved to 1.5% (p<0.05). No patient died after OGR (0% vs 6.5%, p<0.04). As all patients with significant individual risk profiles were treated by TEAM, MR slightly increased (2.9%), but the difference remained insignificant (2.4% in period 2). CONCLUSIONS: risk adjusted selection of treatment modality influences the results after OGR significantly, thereby reducing overall MR of elective AAA treatment.

Aged↗
PubMed2003

Child-Pugh versus MELD score in predicting survival in patients undergoing transjugular intrahepatic portosystemic shunt.

BACKGROUND: In patients undergoing transjugular intrahepatic portosystemic shunt (TIPS), prognostic scores may identify those with a poor prognosis or even those with a clear survival benefit. The Child-Pugh score (CPS) is well established but several drawbacks have led to development of the model of end stage liver disease (MELD). AIM: The aim of the study was to compare the predictive power of CPS and MELD, to validate the original MELD formula, and to assess the predictive value of the determinants used in the two prognostic scores outside of a study setting. PATIENTS: A total of 501 patients underwent elective TIPS placement and 475 patients fulfilled the inclusion criteria. METHODS: Data of all patients undergoing elective TIPS in one university hospital and four community hospitals in Vienna, Austria, between 1991 and 2001, were analysed retrospectively. The main statistical tests were Cox proportional hazards regression model, the log rank test, Kaplan-Meier analysis, and concordance c statistics. RESULTS: Median follow up was 5.2 years and median survival was 4.6 years. During follow up, 230 patients died, 75 within three months after TIPS placement. In stepwise proportional hazards analyses, independent predictors of death were creatinine level, bilirubin level, age, and refractory ascites. MELD was better in predicting survival in a stepwise Cox model but both scores were equally predictive in c statistics for one month, three month, and one year survival. Renal function was the strongest independent predictor of survival. CONCLUSIONS: Although MELD was the primary predictor of overall survival in multivariate analysis, c statistics showed that both scores can be used for patients undergoing TIPS with equal accuracy. For assessing prognosis in patients undergoing TIPS implantation, there seems little reason to replace the well established Child-Pugh score.

Adult↗
PubMed2003

Feasibility study of NeoMend, a percutaneous arterial closure device that uses a nonthrombogenic bioadhesive.

OBJECTIVE: The aim of this prospective single-center phase I feasibility study was to investigate the safety and efficacy of a novel vascular sealing device, the NeoMend Arterial Closure Device, that uses a bioadhesive after percutaneous endovascular procedures. SUBJECTS AND METHODS: In 26 consecutive patients, the sealing device was deployed at the femoral artery access site immediately after a catheterization procedure using a 6-French (1.91-mm) sheath. Patients were followed up at 24 hr with Doppler sonography of the treated femoral artery puncture site, and at 1 week and 1 month by a telephone interview. RESULTS: Successful hemostasis was achieved with the NeoMend Arterial Closure Device in 21 (88%) of 24 patients. One major complication required surgery: formation of puncture site hematoma and pseudoaneurysm 3 days after the intervention after successful primary hemostasis. Two device failures required crossover to manual compression, which was done without further complications. The mean time to hemostasis was 7.0 +/- 4.5 min. Mean time to ambulation was 6.0 hr. At follow-up, the patients did not report any puncture-site-related complaints. Doppler sonography of the puncture sites revealed three insignificant hematomas of less than 20 mL and patent common femoral vessels without stenoses. CONCLUSION: The NeoMend Arterial Closure Device appears to achieve rapid hemostasis with the potential of early ambulation after arterial punctures with a 6-French sheath. The device is an alternative in situations in which suture- or collagen-mediated devices show high complication rates.

Adult↗
PubMed2002

Predictors of long-term results after treatment of iliac artery obliteration by transluminal angioplasty and stent deployment.

PURPOSE: To investigate initial and long-term success rate after percutaneous treatment of iliac artery occlusion with angioplasty and stent deployment. To investigate the influence of vascular comorbidity, lesion length, stent placement and lesion coverage as possible predictors of outcome. METHODS: Between January 1994 and December 1999, 80 iliac recanalizations were performed on 78 patients, median age 61.1 +/- 11.5 (SD) years. All patients were followed up by clinical examinations, duplex ultrasound and intravenous digital subtraction angiography. Mean follow-up time was 2.0 +/- 1.53 (SD) years. Multivariate Cox regression analysis was used to determine the influence of cofactors on patency. RESULTS: One, 2 and 4 years after recanalization, primary patency was 78.1%, 74.5% and 64.0%; secondary patency was 88.8%, 88.8% and 77.9%, respectively. Patients with shorter occlusions, complete lesion coverage and patent ipsilateral femoral arteries had significantly longer patency rates. Complications included inguinal hematoma (n=1), technical failure (n=3) aortic dissection (n=1), embolic occlusions (n=7), gluteal claudication (n=1) and genital necrosis after subsequent urethral surgery in one patient with contralateral occlusion and ipsilateral overstenting of the internal iliac artery with subsequent stenosis. Complications were of permanent clinical significance in seven of 78 (9%) of the patients. In 17 (22%) cases, percutaneous reintervention was performed with angioplasty in the stent (n=16) or deployment of a new stent (n=1). CONCLUSION: Endoluminal stent placement has its place in an interdisciplinary therapeutic approach as a viable therapeutic alternative to major transabdominal bypass surgery and can be performed with comparable complication rates. Patients with short occlusions, patent femoral arteries, and stents covering the entire occlusion have significant longer patency.

Adult↗
PubMed2002

Activation of nuclear factor-kappa B significantly contributes to lumen loss in a rabbit iliac artery balloon angioplasty model.

BACKGROUND: To investigate the contribution of inflammation to postangioplasty lumen loss, we used an adenoviral gene therapy approach to inhibit the central inflammatory mediator nuclear factor-kappaB (NF-kappaB) by overexpression of its natural inhibitor, IkappaBalpha. METHODS AND RESULTS: The adenovirus carrying human IkappaBalpha was applied immediately after balloon dilatation by a double-balloon catheter in a rabbit iliac artery restenosis model. Immunohistochemistry of IkappaBalpha revealed that mainly smooth muscle cells of the media but also cells of the adventitia were transduced and expressed the transgene IkappaB alpha for >/= 8 days. At this time point, intercellular adhesion molecule-1 (30%) and monocyte chemotactic protein-1 (50%) expression, as well as recruitment of macrophages into the wounded area (90%), were significantly reduced in IkappaB alpha-treated vessels. In addition, expression of inhibitor of apoptosis proteins was reduced and the percentage of apoptotic cells was increased compared with control-treated contralateral vessels. Animals killed 5 weeks after treatment exhibited a significantly reduced degree of lumen narrowing (P<0.02) on the side treated with adenovirus IkappaBalpha. The lumen gain of approximately 40% was due to positive remodeling. CONCLUSIONS: From these data, we conclude that balloon angioplasty-induced activation of NF-kappaB contributes to lumen loss likely via induction of an inflammatory response and a decrease in the rate of apoptosis. These data show for the first time that inflammation mediated by NF-kappaB is involved in postangioplasty lumen narrowing. Specific and more potent inhibitors of NF-kappaB might therefore be a useful therapeutic measure to improve clinical outcome after balloon dilatation.

Adenoviridae↗
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↗
PubMed2002

[Temporary and permanent vena cava filter for prevention of pulmonary embolism].

Inferior vena cava filters have been used for prophylaxis of pulmonary embolism since the end of the sixties. Complication rates depend on the types of filters used and are reported to be 2% with the Guenther-Filter and 21% with the Titanium-Greenfield-Filter. Depending on the exact indication both filter types are useful instruments for the prevention of pulmonary embolism.

Equipment Design↗
PubMed2001

[MRI-assisted brachytherapy of nonresectable liver metastases. Preliminary technical and clinical experiences].

PURPOSE: To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis. METHODS: Liver metastases (0.8-5.2 cm in diameter) were treated during a prospective phase I/II study using an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were placed percutaneously under MR-guidance in an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen) using fast T1-weighted sequences. Pretreatment and follow-up studies were performed using a 1.5 Tesla MR system. RESULTS: Preliminary results of an unpublished prospective study are discussed exemplary on 2 selected patients. The median procedure time was 4.9 h. No major complications were observed and late effects were acceptable. In large symptomatic metastases only a temporary relief of pain was achieved. In smaller metastases (DM 3 cm) a tumor control was observed. CONCLUSION: MR-guided brachytherapy is feasible and has the potential to ablate liver metastases with diameter of less than 3 cm. Further developments are necessary.

Adenocarcinoma↗
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

Interventional stent implantation in a child with patent ductus venosus and pulmonary hypertension.

UNLABELLED: We report on the rare case of a 4-year-old boy with patent ductus venosus and pulmonary hypertension presenting with progressive fatigue, tachypnoea at rest and tachycardia. Cardiac catheterisation revealed suprasystemic pressure in the pulmonary arteries with severely elevated pulmonary vascular resistance. In order to reduce the diameter of the ductus venosus, a stent was implanted interventionally, which closed, as expected, spontaneously 2 years later. Pulmonary arterial pressure and pulmonary vascular resistance decreased significantly and the general condition of the boy improved dramatically. CONCLUSION: To the best of our knowledge, this represents the first report of successful interventional stent occlusion of a patent ductus venosus associated with severe pulmonary hypertension. The future will tell whether this intervention is curative or represents a bridging procedure for subsequent liver transplantation.

Child, Preschool↗
PubMed2001

PTA versus Palmaz stent placement in femoropopliteal artery obstructions: a multicenter prospective randomized study.

PURPOSE: To evaluate if stent placement is superior to percutaneous transluminal angioplasty (PTA) in the treatment of chronic symptoms in short femoropopliteal arterial lesions. MATERIALS AND METHODS: One hundred fifty-four limbs in 141 patients who ranged in age from 39 to 87 years (mean age, 67 years) were randomized to PTA (n = 77) versus PTA followed by implantation of Palmaz stents (n = 77). Inclusion criteria were patients with intermittent claudication (n = 108, Society of Vascular Surgery/International Society of Cardiovascular Surgery [SVS-ISCVS] categories 1-3) or chronic critical limb ischemia (n = 46 with either ischemic rest pain [category 4] or minor tissue loss [category 5]), short stenosis or occlusion (lesion length < or = 5 cm), and at least one patent run-off vessel at angiography. Follow-up included clinical assessment, measurement of ankle/ brachial index (ABI), color duplex ultrasound, and/or angiography at 6 or 12 months. Angiographic follow-up between 12 and 36 months was available in 46 limbs (29.9%). RESULTS: In the PTA group, initial technical success was achieved in 65 of 77 limbs (84%) versus 76 of 77 (99%) limbs in the stent group (chi2 value = 0.009). Overall, major complications occurred in 3.9% (n = 6); n = 4 in the PTA group compared to n = 2 in the stent group. There was no difference between groups of treatment: hemodynamic/clinical success at 1 and 2 years in the PTA group was 72% and 65% versus 77% and 65% in the stent group (Gehan P value = .26). The cumulative 1- and 2-year angiographic primary patency rates were 63% and 53%, respectively, for both groups. The secondary 1- and 2-year angiographic patency rates were 86% and 74% in the PTA group versus 79% and 73% in the stent group (P = .5). CONCLUSION: After stent placement, the primary success rate was significantly higher than after PTA. However, 1-year angiographic and clinical/hemodynamic success was not improved.

Adult↗