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Biomedical subjects

G Kretschmer

Publications and source records attributed to G Kretschmer.

At least 37 records · Page 2Linked to original sources
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

Endovascular AAA treatment: expensive prestige or economic alternative?

OBJECTIVES: To compare the costs of endovascular aneurysm treatment versus open surgery during the perioperative period. METHODS: Retrospective analysis of a consecutive series of 44 patients undergoing infrarenal abdominal aneurysm repair from February 1995 to March 1996 at a university teaching hospital. RESULTS: No endovascular procedure was converted to open repair. Operative time was shorter for endovascular treatment (207.6 min vs. 229.1 min, n.s.), as well as postoperative intensive care unit stay (ICU, 22.7 h vs. 55.0 h, p = 0.017) and the postoperative recovery period (5.6 days vs. 13.3 days, p < 0.001). Open surgery generated significantly more costs (25,374.07 ECU vs. 22,268.78 ECU, p < 0.001), despite evaluation and a more expensive endovascular procedure (10,699.48 ECU vs. 4032.01 ECU, p < 0.001). During the study, costs for open surgery exceeded the cost for endovascular treatment by 13.95%. CONCLUSIONS: Endovascular aneurysm treatment is cost effective and less expensive than open surgery. The main reason for cost saving is faster patient recovery after surgery, associated with a shorter LOS in the patients treated with endovascular procedure.

Aged↗
PubMed1997

Treatment of abdominal aortic aneurysms with transfemoral placement of stent-grafts: complications and secondary radiologic intervention.

PURPOSE: To determine the rate of complications of transluminally placed endovascular stent-grafts in patients with abdominal aortic aneurysms and to assess efficacy of secondary radiologic intervention. MATERIALS AND METHODS: In 28 patients, covered nitinol stents were implanted. Frequency and outcome of complications were evaluated after stent-graft placement (mean follow-up, 8.2 months). RESULTS: In 27 patients, 11 tube and 16 bifurcated grafts were implanted successfully. In one (4%) patient, distal migration of a bifurcated graft necessitated conversion to standard open repair. Technical success rates (successful deployment of the device and complete exclusion of the aneurysm at intraoperative angiography) for bifurcated and tube grafts were 24% (four of 17 patients) and 91% (10 of 11 patients). After surgery, leaks were seen in six bifurcated and five tube grafts. After secondary intervention, the final exclusion rate for bifurcated and tube grafts was 88% (15 of 17 patients) and 100% (11 of 11 patients), respectively; the overall success rate was 93% (26 of 28 patients) for exclusion of aortic abdominal aneurysms. Stent-graft thrombosis necessitated local thrombolysis in one patient. Overlapping of accessory renal arteries occurred in two patients. CONCLUSION: Complications after stent-graft placement in abdominal aortic aneurysms are frequent. Secondary radiologic intervention is successful in most cases.

Aged↗
PubMed1997

Evaluation of abdominal aortic aneurysm for stent-graft placement: comparison of gadolinium-enhanced MR angiography versus helical CT angiography and digital subtraction angiography.

PURPOSE: To determine whether magnetic resonance (MR) angiography can be used alone to evaluate abdominal aortic aneurysms (AAAs) for endovascular placement of stent grafts. MATERIALS AND METHODS: Sixty-one patients with AAAs underwent gadolinium-enhanced MR angiography of the abdominal aorta and pelvic arteries. Measurements of the size and extent of the AAAs were compared with helical computed tomographic (CT) and digital subtraction angiographic measurements; 95% confidence intervals for the differences in the means were determined. RESULTS: Because of the larger field of view, MR angiography was superior to CT angiography in assessing visceral iliac artery disease. Both modalities were equal in evaluating the proximal extent of the AAA (mean difference, -0.16 mm; 95% CI, -0.31, 0.64) and in measuring all aortic dimensions (e.g., mean difference in the proximal neck diameter, -0.74 mm; 95% CI, -0.98, -0.49). MR angiography was inferior to CT angiography in depicting accessory renal arteries (seven of 12) and in grading renal artery stenoses (sensitivity, 100% [95% CI, 0.90, 1.00]; specificity, 84% [95% CI, 0.74, 0.91]). CONCLUSION: Gadolinium-enhanced MR angiography is a fast, reliable means of providing all the information relevant to the preoperative assessment of endovascular aortic stent-graft placement.

Adult↗
PubMed1997

[Abdominal aortic aneurysm: surgery, indications, technique, outcome].

The fate of a patient with an abdominal aortic aneurysm] (AAA) is influenced by the risk of rupture and embolism. When the indication for operation is considered, individual associated risk factors have to be taken into account. With regard to the literature, the following recommendations concerning indication for surgery can be given: emergency surgery for symptomatic or ruptured aneurysm; elective surgery: aneurysms 5 cm diameter or growing AAA 5 mm/year, patient with acceptable individual risk for operation; asymptomatic aneurysms less than 5 cm in diameter, without growth in patients aged over 75 years and/or considerable perioperative risk should not be operated on: sonography should be done 3-monthly as a continuing control. Finally the results in our institution are presented for elective surgery: 30-day mortality 3.5%, AAA with rupture, no shock: 20%, ruptured AAA with shock 47%, respectively.

Aortic Dissection↗
PubMed1996

Influence of prostaglandin E1 on tissue ischemia during surgical repair of the abdominal aorta.

OBJECTIVE: To evaluate tissue protection by PGE1 during leg ischemia in patients undergoing aortic surgery. DESIGN: Randomized, controlled prospective clinical trial. SETTING: Single university hospital. PARTICIPANTS: 19 consecutive patients undergoing abdominal aortic aneurysm repair. INTERVENTIONS: Patients received infusions of 30 ng/kg/min of PGE1 or saline. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, lactate, creatine phosphokinase, and thromboxane B2 (TXB2) were measured. In the control group, the decrease in cardiac index (CI) after aortic cross-clamping (AXC) persisted until unclamping together with a decrease in femoral venous O2 content (CfvO2). In the PGE1 group, CI returned to baseline with a trend toward greater CfvO2 levels. During reperfusion in the PGE1 group, O2 consumption and lactate levels exceeded preclamp values. Pulmonary hypertension occurred equally in both groups but did not correlate with TXB2, which was not altered by surgery or by PGE1 infusion. CONCLUSIONS: Intraoperative PGE1 treatment offers no benefit and may exacerbate tissue ischemia during AXC by redistributing microcirculatory flow or limiting cellular oxygen utilization in a manner that overwhelms any possible protective effect.

Aged↗
PubMed1996

Experience in renal autotransplantation: analysis of a clinical series.

OBJECTIVE: To determine the benefit of renal autotransplantation in selected patients with either renovascular lesions, renal or urothelial carcinomas or other disorders of the urinary collecting system. PATIENTS AND METHODS: Between 1977 and 1994, 12 patients underwent renal autotransplantation, six involving renovascular hypertension, two involving tumours of the renal parenchyma, two with urothelial tumours and two with long ureteric stenoses. Pre-operative renal function was normal in six patients and impaired in five. One patient was on haemodialysis. Five patients had a solitary kidney and four patients had functionally solitary kidneys. The follow-up period ranged from 1 to 93 months (mean 34.9). RESULTS: Post-operatively, six patients had normal kidney function (serum creatinine < or = 12 mg/L), five patients had impaired renal function (creatinine content < or = 26 mg/L) and one patient was on haemodialysis due to arterial graft thrombosis. Serum creatinine levels improved in four patients and were stable in another four. Renal function deteriorated in three patients and one patient required a graft-nephrectomy. Immediate post-operative complications included arterial thrombosis in one patient, perirenal haematoma in two, pulmonary oedema in one and severe intra-operative bradycardia requiring a transient cardiac pacemaker in one. CONCLUSION: Renal autotransplantation represents an effective alternative treatment with good long-term results for selected patients with long ureteric lesions and renovascular disorders. It is also an effective method for patients with urological malignancies, especially those with solitary kidneys where the maintenance of renal function is of major concern.

Adult↗
PubMed1994

The choice of material for above-knee femoropopliteal bypass. A 20-year experience.

OBJECTIVE: The choice of material for above-knee femoropopliteal bypass grafting is a matter of continuing controversy for various reasons. The most important argument in favor of alloplastic grafts is to preserve the autologous saphenous vein for a below-knee bypass, which might become indicated at a later date. DESIGN: A consecutive series of above-knee reconstructions were analyzed with regard to long-term behavior. Early graft occlusions were not included, and the median follow-up was 83 months. SETTING: A university hospital with a particular interest in vascular surgery. PATIENTS AND METHODS: Four hundred forty-two patients received either autologous saphenous vein (n = 310) or alloplastic graft (n = 132) material, and were analyzed in a univariate (Kaplan-Meier) and multivariate (Cox) manner. MAIN OUTCOME MEASURES: Analysis as to whether alloplastic graft material provides equal or less favorable results as compared with autologous saphenous vein material, in terms of primary and secondary patency, secondary below-knee bypass grafting, limb salvage, and survival. RESULTS: Although univariate analysis demonstrated a significantly better primary patency rate for autologous saphenous vein material, multivariate analysis did not show any effect of the material in terms of patency, limb salvage, and survival. The frequency of secondary below-knee repair was 7% (31 patients); 56% were performed in the first 2 years postoperatively. This amounted to an estimated probability of 4.4% and 12.3% at 18 years, respectively. CONCLUSION: The small probability of secondary below-knee repair in our series does not support the policy to use alloplastic grafts routinely for a primary above-knee bypass, to spare the saphenous vein. Therefore, patients should be offered the best material for the first operation even at the above-knee level.

Adult↗
PubMed1994

The value of obturator canal bypass. A review.

OBJECTIVE: To review the value of obturator canal bypass with respect to long-term results. DESIGN: Case series and literature review. SETTING: University of Vienna Medical School in Austria. PATIENTS/METHODS: Personal experience with 34 consecutive patients and 125 cases published since 1982 with respect to patient data, patency, and survival are compared and jointly analyzed retrospectively. INTERVENTIONS: Patients received obturator canal bypass for lesions of the pelvic or common femoral vessels precluding orthotopic reconstruction. MAIN OUTCOME MEASURES: The rates of patient survival, limb salvage, and graft patency were analyzed. RESULTS: The postoperative mortality rate in the present series was 14.7%. The limb salvage rate after 5 years was 76.5%. One- and 5-year secondary patency rates were 75.3% and 54.9%, respectively. All grafts in patients without atherosclerosis were patent at a median of 34 months. For 57 cases documented in the literature, 1- and 5-year patency rates were 70.8% and 59.7%, respectively. Combined analysis of 90 obturator canal bypasses revealed rates of 72.7% and 56.9% of patent grafts at 1- and 5-years, respectively. CONCLUSIONS: The use of obturator canal bypass is recommended in deep groin infections and especially in patients with lesions of the pelvic vessels due to other occlusive vascular disease.

Aged↗
PubMed1994

[Discussion comment: surgical therapy of thrombosis of leg and pelvic veins].

Referring to a survey of the literature and the own clinical series the open problems in the surgical treatment of acute iliofemoral venous thrombosis are discussed. Only 2 reports have been published, which test 2 therapeutical options, surgery versus oral anticoagulant treatment in a randomised trial. Nevertheless there have been some shortcomings. Therefore a further clinical trial, with multicentre design, probably guided by a scientific society, seems justified to settle the remaining questions.

Femoral Vein↗
PubMed1994

[Diabetes mellitus and vascular surgery: a retrospective, multivariate analysis].

The influence of diabetes mellitus on the outcome of arterial reconstructions was evaluated. 25.7% of 2,735 patients (average age: 63.7 years), who underwent arterial reconstruction for arterial occlusive disease, suffered from a diabetes mellitus in need of treatment. The sex ratio within the diabetic patients was 2:1 (male:female). Regardless other influencing factors insulin-depending diabetic patients (average age: 64.6 years) were operated in average 1 year earlier than non-diabetics (average age: 65.5 years). No significant differences were found for perioperative complications. Overall, diabetic patients live significantly shorter than non-diabetics (average age: 72.8 vs. 75.8 years). Concerning the survival after the operation a stronger influence can be seen (8.3 vs. 4.4 years). The lower extremity was found to be the main localization for this negative observation on survival of patients (femoro-popliteal: 8.3 vs. 3.5 years; femoro-crural: 7.7 vs. 3.8 years). No statistical significant differences between diabetics and non-diabetics were found concerning patency rates of a reconstruction of the carotid, the aortic or the iliac arteries. There was a slight tendency pointing to a worse patency in diabetics undergoing reconstruction of the femoro-popliteal level (diabetics: 77%/1, 63%/3, 38%/5 years; non-diabetics: 80%/1, 67%/3, 58%/5 years), but this tendency did not reach statistical significance. A similar result was seen in patients with femoro-crural reconstructions (diabetics: 67%/1, 51%/3, 43%/5 years; non-diabetics: 68%/1, 56%/3, 49%/5 years). We were forced to perform a major amputation significantly more often in diabetics than in non-diabetics (13% vs. 7% after 1 year).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Surgical therapy of acute thrombosis of leg-pelvic veins].

A series of 213 consecutive patients suffering from acute iliofemoral vein thrombosis who underwent venous thrombectomy is analyzed. Surgery was performed from an inguinal approach with a Fogarty-balloon-catheter from the proximal vessel and by bimanual exprimation from the femoral and popliteal veins. Post-operative oral anticoagulation treatment was attempted whenever possible. Long term results obtained in 130 patients after a median follow-up of 78 months (44% free of symptoms, 33% PTS [postthrombolic syndrome] I, 15% PTS II, 8% PTS III) showed a significant correlation to the duration of preoperative anamnesis: < or = 5 days: 64% free of symptoms, > 5 days: 34% free of symptoms, the rate of PTS III was equally distributed in the group with long (< or = 5 days) and short (> 5 days) anamnesis (8 and 9% respectively). Postoperative Dicumarol-therapy decreased the rate of severe PTS: 28% without, respectively 10% with therapy. If the medication was cancelled aggravation of the clinical symptoms in 1 third of the patients was observed. Venous thrombectomy is an important treatment option in patients with contraindications to thrombolytic therapy. With patients younger than 65 years and short anamnesis functional results are acceptable, high risk patients (severe cardiac disease and previous pulmonary embolism) should be treated with medical therapy only.

Female↗
PubMed1993

Anticoagulants, antiaggregants or nothing following carotid endarterectomy?

Carotid endarterectomy (TEA) has proven to be beneficial for symptomatic patients. Anticoagulation (AC) and antiplatelet therapy (ASA) have been shown to prolong life following vascular surgery in patients with occlusive arterial disease (PAOD). To determine whether ASA or AC prolong life after TEA, retrospective analysis was undertaken, since cerebral haemorrhage is associated with the use of both drugs, especially AC. Between 1979-1986, 328 patients with stenotic lesions of the carotid bifurcation were operated upon electively. Patient survival and causes of death were the primary end points of the analysis. Recent data were obtained from the Austrian Central Bureau of Statistics. Cumulative survival rates were calculated by Kaplan-Meier estimation and differences determined by Breslow and Mantel tests. 36 patients were on AC, 157 on ASA and 135 remained without medication (0-group). Since the common risk factors in PAOD were unevenly distributed between groups, a stepwise Cox regression model was applied which revealed age (p < 0.01), cardiac pathology (p < 0.01) and diabetes (p < 0.05) as relevant for survival. Therefore, ASA patients and 0-group patients were selected and matched, employing the aforementioned prognostic criteria, and compared to the patients on long-term AC for various indications (vein bypass surgery, myocardial infarction, pulmonary embolism; i.e. data-matching). The median postoperative survival was 7.72 years for ASA and 8.48 years for AC, compared to 6.07 years for the 0-group (p = 0.0095 Breslow, p = 0.477 Mantel). There was no significant difference between AC and ASA treated patients. Irrespective of medication, the causes of death were well balanced, and no higher incidence of intracerebral haemorrhage was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Doppler ultrasound of the saphenous vein as a bypass. Detection of arteriovenous fistulae].

In 13 patients who underwent a femorodistal revascularisation with an in situ saphena vein graft and who had been operated on by angioscopic technique, intraoperative angiography and postoperative colour-coded Doppler sonography and i.v./i.a. digital subtraction angiography (DSA) were performed to detect arteriovenous fistulas (AV fistulas). In intraoperative completion angiography no AV fistulas were seen. Colour-coded Doppler sonography and DSA studies performed three to five days postoperatively revealed AV fistulas in 8 patients. The fistulas could be exactly located by sonography, and, if confirmed haemodynamically significantly by i.v./i.a. DSA, they were marked on the skin and ligated. In the detection of AV fistulas in in situ saphenous vein grafts operated by angioscopic technique colour-coded doppler sonography and i.v./i.a. DSA showed equivalent results. In the detection of connections of AV fistulas to the deep draining veins the i.v./i.a. DSA was superior.

Aged↗
PubMed1992

A decade of oral anticoagulant treatment to maintain autologous vein grafts for femoropopliteal atherosclerosis.

To determine whether long-term oral anticoagulant treatment was effective in improving graft performance and preventing major amputation following vein bypass surgery for femoropopliteal atherosclerosis, a clinical trial was conducted in one single center and continued during 10 years. After 130 patients had electively received a femoropopliteal vein graft, they were randomly assigned to a therapy group (treatment with phenprocoumon [n = 66]) or to a control group (n = 64) that remained without any anticoagulant treatment. Primary end points of the study were graft reocclusion and limb loss. The median durations of primary patency and limb salvage were significantly longer for treated patients than that for controls. In addition, survival in the therapy group was longer. Following autologous vein bypass surgery in the treated group, the results were superior in terms of graft patency, limb salvage, and survival.

Administration, Oral↗