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P Polterauer

Publications and source records attributed to P Polterauer.

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↗
PubMed2004

Experimental comparison of four methods of end-to-side anastomosis with expanded polytetrafluoroethylene.

BACKGROUND: Four established techniques of distal end-to-side anastomosis (direct anastomosis, Linton patch, Taylor patch and Miller cuff) were compared to investigate the local distribution of anastomotic intimal hyperplasia. The study aimed to elucidate whether mechanical factors or flow alterations are mainly responsible for the improved patency rates reported for vein cuff interposition techniques in infrainguinal arterial reconstructions using prosthetic graft material. METHODS: Thirty-two expanded polytetrafluoroethylene (ePTFE) femoropopliteal bypass grafts were implanted in 16 sheep using the four anastomotic techniques. After 6 months the grafts were explanted and examined histologically. The local distribution of intimal hyperplasia was determined, particularly for areas of material transition and of high and low shear stress. RESULTS: The mean amount and distribution of intimal hyperplasia were similar for all anastomotic types. Intimal hyperplasia was greatest along all transitions between ePTFE and venous patches, and between ePTFE and recipient artery. It was lower along the transitions between venous patches and artery, and was lowest at the host artery floor. CONCLUSION: Vein interposition did not reduce anastomotic intimal hyperplasia and did not change the distribution patterns of hyperplasia, which were influenced mainly by mechanical factors. The effect of vein interposition is to move areas of maximum intimal hyperplasia away from the small recipient artery up to the more capacious graft-patch anastomosis.

Anastomosis, Surgical↗
PubMed2004

Limb-salvage by femoro-distal bypass and free muscle flap transfer.

OBJECTIVES: To evaluate the feasibility and long-term outcome of distal arterial reconstruction combined with free muscle flap transfer for patients who would otherwise have undergone major amputation. METHODS: Between 1996 and 2001, 27 reconstructions using autologous vein were performed in 25 patients. Seventeen of these patients had diabetes mellitus. Gracilis, rectus abdominis and latissimus dorsi muscles were used as free flaps, covered with split-thickness skin grafts. RESULTS: Eighty-five percent of patients had a patent graft and viable muscle flap after 1-month. Mean follow-up was 51 months (4-72 months). At the time of follow-up 77% of reconstructions were patent and 70% of patients regained full functional capacity of their lower extremities. CONCLUSION: Limb-salvage by distal arterial reconstruction and free muscle flap transfer, is feasible with low mortality and morbidity and provides excellent long-term results with regard to graft patency and functional status.

Arteriovenous Shunt, Surgical↗
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

Delivery of high dose VEGF plasmid using fibrin carrier does not influence its angiogenic potency.

Delivery of DNA mixed with a degradable matrix carrier was supposed to improve transgene expression. Using a rabbit hind-limb ischemia model, we tested the angiogenic potency of plasmid encoding human vascular endothelial growth factor (pSG5-VEGF165) entrapped in fibrin sealant. Animals were injected intramuscularly with 500 microg of pSG5-VEGF165 or control plasmid, dissolved in saline (PBS) or fibrin glue. After 14 days, presence of delivered constructs and expression of transgene was confirmed in injected muscles of all animals. There were no significant differences in the levels of human VEGF mRNA and protein between VEGF-PBS and VEGF-fibrin groups (Mann-Whitney test). Accordingly, pSG5-VEGF165 regardless of the way of delivery, induced similar increases in capillary density within treated muscles (ANOVA). Control plasmid did not show any effects. In conclusion, injection of pSG5-VEGF165 into ischemic adductor muscle leads to synthesis of human VEGF and increases the number of capillaries. Fibrin carrier does not influence its angiogenic potential.

Animals↗
PubMed2001

In vivo magnetic resonance micro-imaging of the human toe at 3 Tesla.

The feasibility of in vivo high-resolution magnetic resonance micro-imaging of fine anatomic structures of human toes was tested. Five healthy subjects were investigated on an experimental 3 Tesla whole body scanner, using standard 3D gradient echo sequences. A radio-frequency surface coil was used for signal detection. Feet, toes and surface coil were comfortably fixed using a home built device for positioning and reduction of motion artifacts. The spatial resolution of 117 x 313 x 375 microm(3) allowed detailed visualization of anatomic structures like skin layers, vessels and nerves. In addition, oval structures with diameters ranging from 500 to 1000 microm were observed in all subjects, which could represent the sensory nerve endings of Vater-Pacinian bodies. Thus, high resolution MR micro-imaging at 3 Tesla may provide improved morphologic information in distal extremities of humans in vivo.

Adult↗
PubMed2001

Collagen versus gelatin-coated Dacron versus stretch polytetrafluoroethylene in abdominal aortic bifurcation graft surgery: results of a seven-year prospective, randomized multicenter trial.

BACKGROUND: A prospective randomized multicenter trial was performed to compare knitted gelatin-coated Dacron bifurcation grafts, knitted collagen-coated Dacron grafts, and stretch polytetrafluoroethylene (PTFE) grafts. METHODS: Between 1991 and 1998, 315 elective patients were randomized by age, gender, diabetes, runoff, indication (aneurysm, aortoiliac occlusive disease), and nicotine consumption at 3 centers of vascular surgery in Austria. The patients received gelatin-coated Dacron (GEL-D) grafts (n = 109), collagen-coated Dacron (COL-D) grafts (n = 100), or stretch PTFE grafts (n = 106). RESULTS: No intraoperative deaths occurred. The 30-day mortality was 3%. No difference was found between the 3 graft materials in long-term patency. The primary 5-year patency rates were 92% for GEL-D, 89% for COL-D, and 91% for stretch PTFE (P =.6001). The secondary 5-year patency rates also differed: 97% for GEL-D, 100% for COL-D, and 97% for stretch PTFE (P =.2062). Early occlusions were observed overall in 3% and late occlusions in 5% of patients. When both Dacron grafts were compared collectively with stretch PTFE, a difference was found in infection rate: Dacron 3% (6/209) versus PTFE 0% (0/106); P <.03. CONCLUSIONS: The bifurcation grafts of all 3 materials were comparable in primary and secondary patency rates, incidence of false aneurysms, and rate of perioperative complications. Graft infections were confined to the 2 Dacron grafts and did not occur in stretch PTFE grafts.

Aorta, Abdominal↗
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

[Endovascular (transfemoral endoluminal aneurysm management; TEAM) versus conventional open therapy in abdominal aortic aneurysms (AAA): analysis of a clinical series].

All patients (n = 826) treated electively at the Department of Vascular Surgery University of Vienna, Austria, for their AAA during the years 1965-2000 were analysed with particular emphasis on endoluminal repair. Data collection was carried out in retrospect. The operative mortality or within 30 days was considered the primary endpoint of the study. Since 1995 the TEAM approach was available. From that point in time 45.5% of the AAA were treated electively in the endoluminal way. An exploratory analysis of the clinical series revealed a statistically significant difference in the incidence of various risk factors between groups in favor of open repair. Consequently a conditional regression analysis demonstrated the operative method, median patient's age (above versus below 72 years of age), reduced renal and/or pulmonary function to be of significant influence.

Aged↗
PubMed2001

[Preoperative risk factors as deciding criteria in surgical treatment strategy of infrarenal aortic aneurysm].

Significant risk factors of operative therapy in patients with infrarenal aortic aneurysms (AAA) were determined. Best treatment strategy (open surgical repair, transluminal endovascular aneurysm management (TEAM) or conservative treatment) was selected on the base of evaluated risk factors, tendency of rupture and life expectancy. Of the typical risk factors impaired renal and/or lung function showed a significant influence on hospital mortality. In patients without these significant risk factors open surgical repair leads to good clinical results. Acceptable postoperative mortality rates after elective exclusion of an AAA with average size in patients presenting significant comorbidities can only be achieved using TEAM. If TEAM can not be performed, open surgery is only justified in the case of very large AAA diameter.

Aged↗
PubMed2000

[Glomus caroticum chemodectoma. Review on current diagnosis and therapy].

Carotid body tumors are rare neoplasms arising from the small chemoreceptor organ in the adventitia of the common carotid bifurcation. Patients with carotid body tumours usually present with a gradually enlarging non-tender anterolateral neck mass. Differential diagnosis includes metastatic lymph nodes, carotid artery aneurysm, salivary gland tumour, branchial cleft cyst, and neurogenic or thyroid tumours. When such a lesion is suspected, a non-invasive Doppler colour flow ultrasonography enables the clinician to arrive at a definite diagnosis. Subsequent arteriography is mandatory, because the finding of an intensely blushing hypervascular mass spreading into the carotid bifurcation further supports the diagnosis and provides accurate preoperative information concerning arterial blood supply. Computed tomography scanning is appropriate to delineate the relation of the tumour to adherent structures, while magnetic resonance tomography demonstrates the relation of the tumour to the adjacent internal jugular vein and the carotid artery. Selective embolization should be performed for safe surgical removal with less bleeding. Early surgery is the treatment of choice and is recommended in order to minimize major risks. Subadventitial resection is the most established technique. Radical resection prevents local recurrence and has the best long-term results. Removal of the internal or common carotid arteries can become mandatory in selected cases of extensive disease. Surgical treatment by an experienced team is associated with considerably low mortality and morbidity.

Adult↗
PubMed2000

Isolation and continuous growth of Chlamydia pneumoniae from arterectomy specimens.

For the purpose of collecting Chlamydia pneumoniae strains of vascular origin that could be grown continuously in vitro, a cell culture system has been established. Using different types of vascular specimens obtained from 38 patients, Chlamydia pneumoniae could be isolated in three (7.9%) cases. The strains were obtained from specimens of the carotid artery, the femoral artery and an infrarenal aneurysm of the abdominal aorta of three male atherosclerosis patients. Thus, viable Chlamydia pneumoniae strains are also present in vascular regions other than those hitherto described.

Aged↗
PubMed2000

Vascular surgery between the millenniums.

Modern diagnostic modalities as well as ongoing improvement of vascular prosthetic material and surgical techniques have stimulated progress in vascular surgery. New discoveries concerning the mechanism of endothelial function, atherosclerosis, developments in gene therapy and endovascular techniques will expand the future therapeutic spectrum of vascular surgery. Endoluminal implantation of stent grafts for the treatment of aortic aneurysm may be a reasonable alternative to conventional surgery, especially in high-risk patients. Long-term results of this procedure, however, are not yet available. Stenting of internal carotid artery stenosis may be considered as an experimental method of treatment. Its feasibility, efficacy, safety and long-term results must be analyzed before the application of the method may be restricted or recommended. Endoluminal irradiation (brachytherapy) reduces intimal hyperplasia/restenosis and can improve the long-term results of percutaneous transluminal angioplasty. Anti-atherosclerotic and anti-aggregatory therapy (with statins, estrogens, antibiotics, nitric oxide precursor/donors, glycoprotein IIb/IIIa receptor inhibitors) will play an important role in the prevention of ischemic diseases and improve the results of surgical/interventional treatment by reducing intimal hyperplasia and restenosis. Gene therapy opens new vistas in vascular medicine. Angiogenetic factors can be used for the treatment of patients with distal occlusion of the peripheral arteries. Gene transfer may be useful in the conservative treatment of progressive aortic aneurysms. A more unified vision toward vascular medicine might be the key for research and development in the future.

Aortic Aneurysm↗
PubMed2000

The role of antithrombotic therapy on the patency of peripheral bypasses.

Peripheral bypass surgery is a well-established treatment for symptomatic atherosclerotic disease of the legs. To improve the long-term patency antithrombotic drugs and other adjuvant treatment are applied. In this review we summarize the results of randomized studies concerning antithrombotic treatment for prophylaxis after peripheral bypass surgery. Heparin is used routinely intra- and perioperatively without strong data, and according to few data low molecular weight heparin may be superior in this situation. Aspirin had positive effects in placebo-controlled studies after infrainguinal PTFE-bypasses, furthermore it is recommended due to its general cardiovascular risk reduction. Ticlopidine improved long-term patency in one randomized study after venous bypass surgery. Otherwise there are some data that long-term oral anticoagulation may be preferable in patients after venous bypass surgery.

Arterial Occlusive Diseases↗
PubMed2000

Prostaglandin E1 reduces ischemia/reperfusion injury by normalizing nitric oxide and superoxide release.

To test the effects of prostaglandin E1 on 2.5 h of ischemia followed by 2 h of reperfusion, continuous nitric oxide measurements (electrochemical) were correlated with intermittent assays of superoxide and peroxynitrite levels (chemiluminescence) and ischemia/reperfusion injury in rabbit adductor magnus muscle. Administering prostaglandin E1 (1 microg/kg) before or during ischemia/reperfusion caused normalization of the release of nitric oxide, superoxide, and peroxynitrite to slightly above preischemic levels. This pattern was dramatically different from that observed during ischemia/reperfusion alone, where nitric oxide concentration increased three times above its basal level. Normalization of constitutive nitric oxide synthase activity in the presence of prostaglandin E1 was associated with a significant reduction of superoxide and peroxynitrite production and subsequent reduction of ischemia/reperfusion injury. At 2 h of reperfusion, vasoconstriction associated with ischemia/reperfusion injury was eliminated, and edema was significantly mollified but still apparent. Prostaglandin E1 treatment does not directly inhibit constitutive nitric oxide synthase, like the inhibitor N(omega)-monomethyl-L-arginine. Some phenomenon associated with ischemia turns on endothelial constitutive nitric oxide synthase to start transforming L-arginine and oxygen into nitric oxide, but prostaglandin E1 seems to inhibit this phenomenon. Thus, essential local L-arginine pools are not depleted, and normal basal levels of essential nitric oxide are maintained, whereas cytotoxic superoxide and peroxynitrite production by L-arginine-deficient constitutive nitric oxide synthase is prevented.

Acetylcholine↗
PubMed2000

[Abdominal vascular surgery emergencies: abdominal aortic aneurysm, acute mesenteric ischemia--indications, technique, results].

Ruptured infrarenal aortic aneurysms and mesenteric ischemia are abdominal emergency situations, which should be treated by vascular surgeons. Modern means of patient transport and specialized emergency centers make it possible to bring patients suspect of having a ruptured aneurysm or a mesenteric ischemia to experienced clinics. Indication for surgery in case of symptomatic or ruptured aortic aneurysms is doubtless absolute. If there is suspicion for a ruptured aneurysm, emergency operation is indicated. In patients having undergone emergency surgery for a ruptured aneurysm of the infrarenal aorta, hospital mortality was 41%. The initial indication for surgery for patients with mesenteric ischemia usually is the "acute abdomen". Mostly only the patient's history reveals the suspicion for this disease. There are no valid radiologic examinations for proving or ruling out mesenteric ischemia. Most of our patients had arterial embolism (64%) as a source of mesenteric ischemia, followed by arterial thrombosis (28%), venous thrombosis (3%) and non-occlusive ischemia (5%). Monitoring of levels of serum lactate can be an additional tool for decision making, if a second look operation is discussed. The key for surgical success with these critically ill patients is shortening of the interval between the first symptoms of the patient and the start of surgical therapy.

Aged↗