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Biomedical subjects

G Kretschmer

Publications and source records attributed to G Kretschmer.

At least 19 recordsLinked to original sources
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

Graft patency and clinical outcome of femorodistal arterial reconstruction in diabetic and non-diabetic patients: results of a multicentre comparative analysis.

OBJECTIVE: in diabetic patients with critical limb ischaemia (CLI) an inferior success rate following infrainguinal bypass surgery is quite often suggested. The aim of this retrospective analysis was, therefore, to evaluate the graft patency and, particularly, the clinical outcome at 1 year in diabetic compared with non-diabetic patients. MATERIAL AND METHODS: two hundred and eleven patients (diabetics 94; non-diabetics 117) with femorodistal reconstruction for CLI were studied. Groups were comparable with regard to the Fontaine classification, the distribution of vascular risk factors, graft material, distal anastomosis site, and the angiographic runoff grading. RESULTS: diabetes did not adversely affect graft function. For diabetics and non-diabetics primary cumulative patency rate at 1 year was found to be 66 and 56%, respectively (p=0.10) and a virtually identical limb salvage rate of 85 and 83% was achieved (p=0.76). With regard to healing of ischaemic foot ulcers a trend against diabetics was noted with a healing rate of 81% compared to 96% in non-diabetics at 1 year (p=0.067); gangrenous foot lesions could be equally remedied in 94% and in 87% among patients with and without diabetes (p=0.44). The survival rate of diabetics, however, was significantly lower with 78% at 1 year compared with 95% in non-diabetic patients (p=0.0004). CONCLUSIONS: our preliminary results support the view that infrainguinal bypass grafting can be safely done even in diabetics. Despite increased mortality in this group, liberal indication for reconstructive vascular surgery seems to be justified by favourable patency rates and clinical outcome in selected patients.

Aged↗
PubMed2002

Fresh arterial homograft transplantation: a novel concept for critical limb ischaemia.

INTRODUCTION: homografts have been used since the early days of vascular surgery, but have failed to provide long-term success. Arteries supplying organ transplants seldom show signs of biodegradation. We therefore introduced fresh arterial homograft repair with consecutive immunosuppression (ATX). AIM: to assess feasibility and clinical usefulness of ATX. SETTING: university teaching hospital. MATERIAL AND METHOD: conduits were harvested during multi-organ procurement and stored in Custodiol. Implantation followed immediately. Viability of the transplant was documented in all cases. Patients received immunosuppression for the duration of bypass function. RESULTS: thirteen patients received ATX for critical limb ischaemia (M/F: 11/2, age: 62yr, previous revascularisations: 4.5 (1-8), median run-off index 5, previous organ transplant: n=2. Most bypasses were anastomosed to single tibial or pedal vessels. There was no early failure. Within an average follow up of 12 months there were 6 graft thromboses in 5 patients, successfully revised in 4. Three limbs were lost after 2, 5 and 6 months due to graft failure. Graft rejection was shown in 1 out of 3 explanted grafts. CONCLUSION: we report a concept, which may circumvent the problem of biologic graft degeneration. Limb salvage was possible in 75% at 12 months in otherwise difficult circumstances.

Adolescent↗
PubMed2001

[Inguinal hernia as a diagnostic error in ruptured groin aneurysm].

Anastomotic aneurysms observed with an incidence of 0.5% to 5.0% are considered a known complication following arterial surgery, especially when fabric grafts in the inguinal region are implanted. An anecdotal report is presented describing a 64-year old male patient, who developed, 10 years following an autologous femoro-tibial vein graft, a huge mass in the left groin. The lesion was considered an incarcerated inguinal hernia and the patient was admitted to the Department of Surgery for emergency repair. Clinical examination, duplexsonography and CT scan clarified the diagnosis of an aneurysm with a diameter of 13 cm. The aneurysm was resected, and a femoro-profundal vein graft was implanted orthotopically, the graft was covered with a sartorius muscle flap. The postoperative course was uneventful. The diagnosis is suspected by clinical examination and usually confirmed by duplexsonography. The exact etiology of suture line aneurysms is unknown; in the present case progression of the underlying arteriosclerotic arterial disease after a follow up of 10 years is likely. For the treatment the usual methods of complicated aneurysm repair and preservation of the arterial circulation--using autologous in situ methods or extraanatomic bypass grafts--with additional biologic coverage are at hand.

Aneurysm, Ruptured↗
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

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

[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

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

Endovascular repair of thoracic aortic aneurysms.

The standard technique for the treatment of descending thoracic aortic aneurysms is elective open surgical repair with graft interposition. This standard approach, although steadily improving, is associated with high morbidity and substantial mortality rates and implies a major surgical procedure with lateral thoracotomy, use of cardiopulmonary bypass, long operation times and a variety of peri- and postoperative complications. This and the success of the first endoluminal treatment of abdominal aortic aneurysms by Parodi et al. prompted the attention to be thrown on the treatment of descending thoracic aortic aneurysms with endoluminal stent-grafts in many large centres. The aim of this new minimally invasive technique is to exclude the aneurysm from blood flow and in consequence to avoid pressure stress on the aneurysmatic aortic wall, by avoiding a large open operation with significant perioperative morbidity. The potentially beneficial effect of this new treatment approach was evaluated in the course of this study.

Adult↗
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↗
PubMed1999

Increased automatic spreading activation in healthy subjects with elevated scores in a scale assessing schizophrenic language disturbances.

BACKGROUND: Previous studies on semantic priming have suggested that schizophrenic patients with language disturbances demonstrate enhanced semantic and indirect semantic priming effects relative to controls. However, the interpretation of semantic priming studies in schizophrenic patients is obscured by methological problems and several artefacts (such as length of illness). We, therefore, used a psychometric high-risk approach to test whether healthy subjects reporting language disturbances resembling those of schizophrenics (as measured by the Frankfurt Complaint Questionnaire subscale 'language') display increased priming effects. In addition, the Schizotypal Personality Questionnaire was used to cover symptoms of schizotypal personality. Enhanced priming was expected to occur under conditions favouring automatic processes. METHODS: One hundred and sixty healthy subjects performed a lexical decision semantic priming task containing two different stimulus onset asynchronicities (200 ms and 700 ms) with two experimental conditions (semantic priming and indirect semantic priming) each. RESULTS: Analyses of variance revealed that the Frankfurt Complaint Questionnaire-' language' high scorers significantly differed from low scorers in three of the four priming conditions indicating increased automatic spreading activation. No significant results were obtained for the Schizotypal Personality Questionnaire total and subscales scores. CONCLUSIONS: In line with Maher and Spitzer it is suggested that increased automatic spreading activation underlies schizophrenia-typical language disturbances which in our study cannot be attributed to confounding variables such as different reaction time baselines, medication or length of illness. Finally, results confirm that the psychometric high-risk approach is an important tool for investigating issues relevant to schizophrenia.

Adult↗
PubMed1999

Oral anticoagulation in peripheral vascular surgery: how intense, for how long, or at all?

To evaluate the influence of postoperative pharmacotherapy (antiplatelet therapy with acetylsalicylic acid (ASA) or oral anticoagulation) following various peripheral vascular surgical interventions (femoro-popliteal reconstruction, femoro-popliteotibial venous bypass;) two clinical series of patients were analysed (A1-2) and we made the hypothesis that adjuvant therapy may be beneficial. Thereafter two clinical trials were carried out (B1-2), to assess the value of postoperative antiaggregant and anticoagulant treatment. It was not possible to demonstrate any influence of ASA on improving patency at the iliaco-popliteal level or on patient survival. It was concluded that the ASA dosage of 1500 mg daily was too high, and produced severe side-effects, probably leading to insufficient patient compliance to therapy. In the B2 trial 130 patients received a femoro-popliteal above- or below-knee vein bypass, and were assigned to the therapy group (n = 66) and treated with anticoagulants or to the control group (n = 64) which received no therapy. During the follow-up, for a maximum of 10 years, the probability of bypass function, limb salvage and patient survival were significantly in favour of the treatment. The described single centre clinical trial B-2 produced in accordance with other trials a level II evidence in favour of postoperative pharmacotherapy. Level 1 trials assessing the direct comparison of antiaggregant versus anticoagulant therapy are underway, but results are unavailable yet, similarly the results of the Antithrombotic Trialist's Collaboration (ATT) are currently unknown.

Administration, Oral↗
PubMed1998

[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↗
PubMed1998

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↗