[Problematic carotid artery surgery versus intervention].
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Angioplasty, Balloon↗
Biomedical subjects
P Polterauer
Publications and source records attributed to P Polterauer.
Influence of MUC18/MCAM/CD146 expression on human melanoma growth and metastasis in SCID mice.
The cell surface glycoprotein MUC18MCAM/CD146 was originally defined as a marker of melanoma progression and has been suspected to be directly linked to the metastatic process of this malignancy. In order to address this question, 2 MCAM negative human melanoma cell lines, SK-2 and XP44RO(Mel), were transfected with MCAM-encoding cDNA. Surface MCAM expression on SK-2 and XP44RO(Mel) transfectants was similar to that observed in naturally occurring MCAM positive human melanoma cells and transfectants demonstrated MCAM-dependent increase in homotypic adhesion in vitro. The growth behavior of 7 MCAM transfectants and their respective vector controls was evaluated in SCID mice. Tumor size at 4-5 weeks after s.c. implantation was highly variable, but did not correlate with MCAM expression. Despite massive primary tumor formation at the injection site, no spontaneous metastasis was observed with any of the investigated MCAM transfectants. The influence of MCAM expression on lung metastases formation in an experimental metastasis assay was system dependent, converting only XP44RO(Mel) transfectants into metastatic cells, although increased homotypic adhesion, leading to formation of tumor cell clusters, was observed with transfectants of both cell lines in vitro. Our findings indicate that MCAM expression of human melanoma cells has an influence on later stages of the metastatic process only, namely, extravasation and establishment of new foci of growth, but is per se not sufficient for this process.
Animals↗
Detection of Chlamydia pneumoniae DNA in atheromatous tissues by polymerase chain reaction.
Chlamydia pneumoniae is an important human respiratory pathogen. Recently, seroepidemiological data and the demonstration of chlamydial DNA or antigen within parts of atherosclerotic lesions have suggested a causal association between chlamydial infections and atherosclerosis. As the results obtained by different groups show considerable variations, we provide further data based on a highly specific and sensitive nested PCR method. Positivity was confirmed by nonradioactive hybridization with a specific probe, and sensitivity was determined by titration experiments. C. pneumoniae DNA was detected in 8/29 (28%) of carotid artery samples and 3/14 (21%) of aortic aneurysms.
Aged↗
Impact of different therapeutic alternatives in treatment of severe limb ischemia: experiences on 190 consecutive patients at a department of medical angiology.
BACKGROUND: Different therapies in consecutive patients (1987-1992) with chronic critical limb ischemia at a department of medical angiology, their short- and long-term outcome were investigated. PATIENTS AND METHODS: 190 patients (112 males, 78 females; age: 67 +/- 12 years); 78 in grade II, 112 in grade III according to Rutherford's classification. Therapeutic regimen: 1. vascular recanalisation by percutaneous transluminal angioplasty [PTA], local or systemic lysis; 2. surgical vascular reconstruction in case of impossibility or failure of catheter procedures; 3. prostanoids and/or antibiotics; 4. local wound treatment including amputations. RESULTS: Vascular recanalisation was attempted in 156/190 (82.1%): PTA in 116/190, surgical vascular reconstruction in 50/190, local in 24/190 and systemic lysis in 8/190 patients. Prostanoids were applied in 89/190 and antibiotics in 73/190 patients. At the time of dismissal 164/190 (86.3%) patients were clinically improved; 11/190 (5.8%) unchanged, 13/190 (6.8%) had undergone major amputations and 2/190 (1.1%) had died. After 2.6 +/- 2.2 years 77 of the 141 patients, who were still alive, were reexamined. Among these 77 patients 84.4% were in grade 0 or 1, 15.6% in chronic critical limb ischemia. Furthermore 13.0% had been amputated since dismissal. Forty-nine of 190 (25.8%) patients had died 3.2 +/- 1.9 years after dismissal from hospital. CONCLUSION: Catheter techniques, mostly PTA, is possible in the majority of patients with chronic critical limb ischemia. Cooperation with vascular surgeons in case of technical impossibility or failure of catheter recanalisation is mandatory. Such a regimen yields satisfactory short- and long-term results and a low rate of complications.
Aged↗
Blood flow in distal end-to-side anastomoses with PTFE and a venous patch: results of an in vitro flow visualisation study.
OBJECTIVES: non-physiological flow behaviour plays a significant role in the development of distal anastomotic intimal hyperplasia. To investigate flow patterns in four anastomotic types of femoral end-to-side distal bypass graft anastomoses, a flow visualisation study was performed. METHODS: transparent 1:1 casted replicas of distal vascular graft anastomoses created by conventional technique, Miller-cuff, Taylor- and Linton-patch were fabricated. A pulsatile mock circulation with a high-speed video system was constructed. Flow pattern was determined at mean Reynolds numbers 100-500. Migrations of the stagnation points on the bottom of the anastomoses at mean Reynolds numbers 100, 230, and 350 were measured. RESULTS: a vortex forms during early systole and increases to maximum systole in all anastomoses. During the diastolic phase the vortex moves in the Miller-cuff distally to the toe of the anastomosis and remains standing, while in the other anastomotic types the vortex moves proximally to the heal of the junction and breaks down. The shift of the stagnation point in the Miller-cuff was considerably smaller than in the other anastomoses. CONCLUSION: conventional, Linton and Taylor anastomoses show similar flow patterns. The Miller-cuff with its wider cavity shows lower shift of the bottom stagnation point, but a persistent washout of the anastomotic cavity, which may contribute to its reported good clinical performance.
Anastomosis, Surgical↗
Systemic blood pressure and cerebral blood flow velocity during carotid surgery.
BACKGROUND: To evaluate the effect of mean arterial blood pressure (MAP) on cerebral perfusion during carotid surgery, we investigated blood flow velocity in the middle cerebral (Vs,mca) using transcranial Doppler ultrasonography (TCD). METHODS: During carotid crossclamping, treatment included either phenylephrine-induced hypertension without shunting (Group XC; n = 11) or insertion of a shunt (Group S; n = 12). RESULTS: Increasing MAP in Group XC before crossclamping (81 + /-13 mmHg to 107 +/- 12 mmHg) caused an increase of Vs,mca (59 +/- 17 cm/s to 75 +/- 20 cm/s; p < 0.001). During crossclamping without a shunt, Vs,mca was not dependent on MAP, and was reduced (mean 47 +/- 24 cm/s) in relation to preclamp values. In Group S, Vs,mca was always dependent on MAP and the preclamp velocity was maintained (before shunt: 75 +/- 26 cm/sec; during shunt: 79 +/- 30 cm/sec). CONCLUSIONS: Although we found an impaired cerebral autoregulation, Vs,mca was independent of MAP during carotid crossclamping. Thus, TCD measurements have to be interpreted with caution during crossclamping, and the effect of induced hypertension has to be confirmed with more invasive measures of cerebral blood flow.
Aged↗
Mutated N-ras upregulates Bcl-2 in human melanoma in vitro and in SCID mice.
Activation of the N-ras gene by point mutation occurs in about 15% of all human melanomas. In recently established severe combined immunodeficiency (SCID) mouse xenotransplantation models for human melanoma, we demonstrated that mutated N-ras not only contributes to tumour growth by enhancing cellular proliferation, but also by blocking apoptosis. Mutated N-ras overexpression protected human melanomas from naturally occurring apoptosis and, in a more pronounced way, from chemotherapy-induced apoptosis in vitro and in vivo. Given the potential clinical importance of these findings we sought to determine the underlying mechanism. We found that mutated N-ras specifically upregulates the expression of the anti-apoptosis gene bcl-2 in two human melanoma cell lines in vitro and in SCID mice. Neither the expression of the anti-apoptotic protein Bcl-xL nor that of the pro-apoptotic proteins Bax and Bak were altered in cells expressing mutated N-Ras. The increase in Bcl-2 expression mediated by mutated ras therefore qualifies as a rational explanation for the enhanced chemoresistance of human melanoma expressing mutated N-Ras.
Animals↗
Evaluation of distal anastomotic intimal hyperplasia: an experimental comparison by arteriography, duplex sonography, angioscopy, and intravascular ultrasound.
Routine follow-up investigation methods after peripheral arterial bypass surgery, such as arteriography and colour duplex sonography, do not always allow correct analysis of moderate alterations in the vessel wall, e.g. initial stages of distal anastomotic intimal hyperplasia (DAIH). The aim of this study was to evaluate the efficiency of angioscopy and intravascular ultrasound compared to the named routine methods regarding detection of early DAIH. Eight months after bilateral femoropopliteal bypass surgery with venous grafts in 18 sheep, we investigated the distal anastomotic sites using the named methods. The findings were then correlated to histologic specimens. Intravascular ultrasound presented the highest sensitivity followed by angioscopy, with results markedly different from the findings arrived at by conventional methods.
Anastomosis, Surgical↗
[Management of severe infection complicating aortofemoral grafts].
OBJECTIVE: Infection of the retroperitoneum after implantation of an abdomino-femoral aortic graft remains one of the main problems in vascular surgery. On basis of a critical review of own experiences we evaluated the management of this difficult clinical situation. PATIENTS: From 1970-1996 1500 aortofemoral graft operations (aneurysmal disease: 512, aortoiliacal occlusive disease: 988) were performed. Abdominal infection occurred in 12 patients (0.8%) (12 men, median age 60.5 [48-80] years). RESULTS: The median interval between operation and infection was 17.7 (0.5-108) months. The port of infection was in 50% the groin, 25% suffered from abdominal infection, in 3 cases it was not to identify. Clinical manifestation of infection was aortoduodenal fistula in 2 patients, false aneurysms in 2 cases, and a paraprosthetic abscess in another 4 patients. Operative therapy comprised (partial) removal of infected material in 10 patients with consecutive extraanatomical reconstruction in 8 of these. Mortality of graft infection was 50%. Causes of death were untreatable sepsis in 4 patients, another 2 died from hemorrhagic shock. 3 out of 6 surviving patients finally lost their limbs following multiple vascular procedures. CONCLUSION: Adequate surgical therapy of infected aortofemoral grafts remains an unsolved problem. Lack of knowledge of suitable parameters for the best treatment leaves the outcome of prosthetic infection unpredictable. Removal of the infected graft with extraanatomic reconstruction seems to be the standard of surgical treatment, which is recommended in these cases.
Aged↗
L-arginine treatment in ischemia/reperfusion injury.
We tested whether treatment with exogenous L-arginine, the precursor of nitric oxide (NO), could protect the skeletal muscle from ischemia/reperfusion (I/R) injury. A rabbit hindlimb I/R model (2.5 h ischemia/2 h reperfusion) was used. Morphological changes were elucidated by morphometry. Plasma concentrations of malondialdehyde (pMDA), as well as L-arginine and L-citrulline content in the plasma and skeletal muscle were measured. I/R injury in the skeletal muscle was manifested by development of prominent interstitial edema (fraction of interfiber area was 26.23% vs 15.09% in sham operated control, p < .005) and severe microvascular constriction (capillary area was 11.41 microns2 vs 16.92 in control, p <.005). These changes were accompanied by increased pMDA levels, indicating a process of lipid peroxidation in the cell membranes. L-arginine treatment (4 mg/kg/min intravenously, for 1 h, infusion initiated 30 min before reperfusion) caused an intracellular accumulation of this amino acid in the SM. Intracellular concentrations of L-citrulline increased (201.0 mumol/dm3 after reperfusion vs 176.0 before ischemia onset, p < .005), suggesting stimulated endogenous NO synthesis. L-arginine treatment protected capillary constriction (capillary area was 17.64 microns2 vs 11.41 in the untreated animals, p < .0005) and reduced interstitial edema after reperfusion (fraction of interfiber area was 17.80% vs 26.23 in untreated animals, p < 0.005). The protective effect of L-arginine treatment on I/R injury of SM may be related to its ability to prevent microvascular constriction and reduce permeability disorders by the stimulation of endogenous NO production.
Animals↗
Endovascular management of "endoleaks" after transluminal infrarenal abdominal aneurysm repair.
PURPOSE: To investigate the reasons for endoleaks after transluminal infrarenal abdominal aneurysm management and the potential for transluminal interventions in subsequent management. METHODS: Prospective analysis of 50 consecutive patients undergoing endovascular aneurysm repair at a single institution with Stentor and Vanguard grafts from March 1995 to March 1997. SETTING: Academic teaching hospital. RESULTS: Two procedures were converted for other reasons than leak. In the remaining 48 successful procedures endoleaks were detected in 11 (22.9%): proximal aortic leak (2.1%), distal aortic leak (8.3%), iliac leak (12.5%). Leaks were treated at the initial procedure in five patients, resulting in 87.5% excluded aneurysms. Twelve and a half per cent were discharged with a primary leak. Redo was performed on all iliac leaks within 7 weeks. All aortic leaks showed spontaneous thrombosis within 3 months, but reappeared with local aneurysm expansion. Aortic redo-procedures were performed by proximal tubular extension or converting a tube graft into a bifurcation graft. All rescue procedures were successful. Secondary leaks have been observed twice in this series, both treated by endovascular means. CONCLUSIONS: Endovascular treatment of primary and secondary endoleaks is possible, and may be a safe alternative to a difficult open procedure.
Aged↗
[Prevalence of abdominal aortic aneurysms: a sonographic screening study].
PURPOSE: To determine the prevalence of abdominal aortic aneurysms (AAA) in males above 60 years of age. METHODS: 1043 males of 60 years of age or older underwent sonographic examinations of the abdominal aorta. All of the candidates had volunteered for the examination, and special care was taken to avoid preselection of the candidates. Wherever possible, information was obtained on the following risk factors: cholesterol level, nicotine, diabetes, insulin and other medication, hypertonia and cardiac risk. RESULTS: An AAA was diagnosed in 2.59% of the cases, while ectasia of the abdominal aorta was detected in 11.89%. The mean diameter of the aneurysms was 39.1 mm. Significant correlations between the various risk factors and abnormalities of the abdominal aorta could be established in patients suffering from angina pectoris (p = 0.004) and from congestive heart failure (p = 0.014). CONCLUSIONS: AAA in males above 60 occurs in 2,590 out of 100,000 cases. The most noteworthy risk factors in the development of AAA are cardiovascular disorders.
Age Factors↗
Monitoring of median nerve somatosensory evoked potentials in carotid surgery.
The purpose of this study was to compare median somatosensory evoked potentials (SEP) in patients undergoing carotid endarterectomy (CEA) with routine shunting and nonshunting (excluding the option of selective shunting) and to evaluate the significance of a decrease in the amplitude of the cortically generated waveforms of the SEP and/or an increase in the central conduction time (CCT) on the one hand, and that of a loss of the cortical SEP, on the other. Somatosensory evoked potentials were recorded in 32 patients before, during, and after CEA with routine shunting or nonshunting. The N13 and N20 latency, the CCT, and the N20/P25 amplitude were evaluated. In addition, a meta-analysis of 15 previous studies was performed comprising a total of 3,136 patients. The intraoperative cortical SEP showed no differences between shunted and nonshunted patients, apart from the preclamping value of the N20/P25 amplitude which was lower in the nonshunted subjects. The number of patients with decreased and/or delayed cortical SEP (findings frequently used as criterion for selective shunting) was similar in the two study groups. A loss of the cortical SEP occurred in one patient operated on without an indwelling shunt. None of these patients had a new neurologic deficit after surgery. In the meta-analysis, the positive predictive value of decreased and/or delayed cortical SEP was extremely poor, that of absent cortical SEP was poor to moderate and the prevalence of new neurologic deficits was similar in patients undergoing CEA with routine shunting-nonshunting and those with selective shunting-nonshunting. Our study suggests that decreased and/or delayed cortical SEP are unreliable predictors of the neurological outcome of CEA patients and consequently an unsuitable criterion for selective shunting. The meta-analysis confirms this finding and shows that the neurologic outcome is not improved by using an indwelling shunt selectively based on SEP monitoring.
Aged↗
L-arginine treatment alters the kinetics of nitric oxide and superoxide release and reduces ischemia/reperfusion injury in skeletal muscle.
BACKGROUND: Constitutive nitric oxide synthase (cNOS) may produce species involved in ischemia/reperfusion (I/R) injury: NO in the presence of sufficient L-arginine and superoxide at the diminished local L-arginine concentration accompanying I/R. METHODS AND RESULTS: During hindlimb I/R (2.5 hours/2 hours), in vivo NO was continuously monitored (porphyrinic sensor), and L-arginine (chromatography), superoxide (chemiluminescence), and I/R injury were measured intermittently. Normal rabbits were compared with those infused with L-arginine 4 mg x kg(-1) x min(-1) for 1 hour. In both groups, approximately 6 minutes into ischemia, a rapid increase of NO from its basal level of 50+/-17 to 115+/-7 nmol/L, P<.005 (microvessels), was observed. In animals not treated with L-arginine, NO dropped below basal to undetectable levels (<1 nmol/L) during reperfusion. In animals treated with L-arginine, the decrease of NO was slower, such that substantial amounts accumulated during reperfusion (25 nmol/L). Decreased NO during I/R was accompanied by increased superoxide, which during reperfusion reached 50 nmol/L without or 23 nmol/L with L-arginine treatment. Calcium-dependent cNOS was a major source of superoxide release (inhibited 70% by L-NMMA and 25% by L-NAME) during I/R. CONCLUSIONS: L-Arginine treatment decreased superoxide generation by cNOS while increasing NO accumulation, leading to protection from constriction (microvessel area, 17.77+/-0.95 versus 11.66+/-2.21 microm2 untreated, P<.0005) and reduction of edema after reperfusion (interfiber area, 16.56+/-2.13% versus 27.68+/-7.70% untreated, P<.005).
Animals↗
Thromboembolic complications in a patient with heparin-induced thrombocytopenia (HIT) showing cross-reactivity to a low molecular weight heparin-treatment with Org 10172 (Lomoparan).
Heparin-induced thrombocytopenia is an immuno-mediated life-threatening side effect of heparin therapy which poses difficulties in diagnosis and major therapeutic problems. Heparin must be instantly discontinued. We describe the case of a 60-year-old male patient with type II heparin-induced thrombocytopenia, complicated by progressive deep venous thrombosis and pulmonary embolism. He failed to improve when therapy was continued with a low molecular weight heparin (Fragmin) and high doses of intravenous immunoglobulins were administered. The test for heparin-dependent platelet aggregation was positive for unfractionated heparin and low molecular weight heparin, but negative for the heparinoid Org 10172. During subsequent anticoagulant therapy with Org 10172 for seven days the number of platelets increased rapidly and the patient recovered. Nine months later Org 10172 was used again in this patient for thrombosis prophylaxis without any adverse effects. In patients with heparin-induced thrombocytopenia requiring immediately acting anticoagulant therapy, Org 10172 can be considered as an effective alternative drug to unfractionated and low molecular weight heparins.
Anticoagulants↗
Endoluminal stent-grafts for infrarenal abdominal aortic aneurysms.
BACKGROUND: The treatment of aortic aneurysms with endovascular stents or stent-graft prostheses is receiving increasing attention as an alternative to major abdominal surgery. To define the clinical value of this technique, we prospectively studied the use of stent-graft endoprostheses made of nitinol and covered with polyester fabric for the treatment of infrarenal abdominal aortic aneurysms. METHODS: We treated a total of 154 patients at three academic hospitals. Twenty-one patients with aortic aneurysms not involving the aortic bifurcation received straight stent-grafts, and 133 patients with aortic aneurysms involving the bifurcation and the common iliac arteries received bifurcated stent-grafts. After a unilateral surgical arteriotomy, the endoprostheses were advanced through the femoral arteries and placed under fluoroscopic guidance. Computed tomography and intraarterial angiography were performed during an average follow-up of 12.5 months. RESULTS: The primary success rate, defined as complete exclusion of the abdominal aortic aneurysm from the circulation, was 86 percent in the group receiving straight grafts and 87 percent in the group receiving bifurcated grafts. In three patients the procedure had to be converted to an open surgical operation. Minor (n=13) or major (n=3) complications associated with the procedure (including 1 death) occurred in 10 percent of the patients. All patients had a postimplantation syndrome, with leukocytosis and elevated C-reactive protein levels. CONCLUSIONS: Our results suggest that endovascular treatment of infrarenal abdominal aortic aneurysms is technically feasible and can effectively exclude abdominal aortic aneurysms from the circulation. With further refinement, endoluminal repair may emerge as an interventional strategy to treat infrarenal aortic aneurysms, especially in patients at high surgical risk.
Adult↗
Diagnostic and therapeutic approaches to carotid body tumors. Review of 24 patients.
OBJECTIVE: To determine the clinical characteristics of carotid body tumors to define better a standardized proceeding in the management of carotid body tumors. DESIGN: Retrospective survey. Duration of postoperative follow-up was 4 months to 16 years (median, 57 months). SETTING: Institutional, tertiary care medical center. PATIENTS: Consecutive sample of 24 patients (10 men and 14 women) with 28 carotid body tumors treated in the University of Vienna (Austria) General Hospital in 35 years. INTERVENTIONS: Surgical resection, preoperative embolization. MAIN OUTCOME MEASURES: Initial signs, duration of symptoms, extension of the tumors, methods of investigations, and treatment modality, with special respect to the operative technique. RESULTS: Doppler color flow imaging and angiography provided essential mainstays for definite diagnosis. Computed tomography and magnetic resonance imaging contributed additional information about tumor extension. Nineteen patients (79%) underwent surgical resection of 22 tumors, 8 (42%) after preoperative embolization. There were no perioperative deaths. Hemiplegia occurred in 1 patient, and cranial nerve palsy occurred in 5 patients. Tumor recurrence was observed in 3 patients. Five patients refused surgery or tumors were unresectable. CONCLUSIONS: Our standard diagnostic procedure consists of establishing diagnosis by Doppler color flow sonography, angiography for detailing the vascularization of the tumor, and selective embolization to enable safer surgery with less bleeding. Early surgery is recommended to minimize major risks.
Adult↗
The first 15 months of transluminal abdominal aortic aneurysm management: a single centre experience.
OBJECTIVES: To assess the early experience with the transfemorally placed modular endovascular MinTec graft (TPEG) for abdominal aortic aneurysm (AAA). DESIGN: One single centre prospective evaluation of the endograft procedure as well as early postoperative results. SETTING: An academic teaching hospital. PATIENTS: 30 consecutive patients treated during a period of 15 months. RESULTS: Peri- and postoperative morbidity and mortality were evaluated according to the recommendations of the Ad Hoc Committee on Reporting Standards. The endograft procedure was successful in 28 patients (93.4%); two patients (6.6%) needed conversion into open conventional y-graft replacement; one patient died 36 days following intervention from multiple organ failure. Another patient died from pancreatitis unrelated to the implantation. Endoleaks were treated by "overstenting" or distal extension of the endografts, but conversions were unnecessary. Five severe adverse events were noted in four patients. CONCLUSIONS: TPEG is a feasible but technically demanding procedure, requiring both surgical techniques and catheter skills. The potential for less operative morbidity and simpler aneurysm management compared to conventional open surgery may be present. Close follow-up of patients is necessary to understand the development and treatment of endoleaks.
Aged↗