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Biomedical subjects

H Schweiger

Publications and source records attributed to H Schweiger.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Follow-up of vena cava filters with color Doppler ultrasound].

In 49 patients, colour-coded Duplex sonography was performed after implantation of a Greenfield caval filter. A plain film radiograph of the abdomen was taken additionally. The examination could be assessed free of artifacts in the longitudinal and transverse section in a total of 41 patients (84%). The procedure facilitates not only a diagnosis of thrombotic changes in the vena cava but can also display the topographical position of the filter and the venous flow. Caval thrombosis was verified in 5 patients. In 7 cases there was a decentral position of the filter apex with tilting. The penetration of filter struts through the vein wall eluded sonographic diagnosis as did morphological changes to the filter (e.g. filter fracture). In combination with the plain film radiograph, colour-coded Duplex sonography can replace cavography or computed tomography in the investigation of position and venous flow.

Adult↗
PubMed1994

[Neuromonitoring in carotid surgery: possibilities and limits of transcranial Doppler ultrasound].

In order to evaluate the suitability of transcranial Doppler sonography as an intraoperative monitor in carotid surgery, we compared measurements of mean blood flow velocity in the ipsilateral middle cerebral artery with the cortical response of somatosensory evoked potentials in a prospective study of 176 carotid operations. SEP recording was readily feasible during all procedures and by means of SEP loss all patients at risk for critical cross-clamp related cerebral ischemia were reliably identified. In contrast, TCD could not be used for assessment of cerebral hemodynamics in more than 40% of patients. What is more, in high risk patients with intraoperative loss of SEP, TCD could not be performed in 74% of cases. This high rate of failure limits the usefulness of TCD as an intraoperative monitor and detracts from the additional benefit of identifying cerebral embolism and hyperperfusion as potential causes of neurological deficits. In contrast to SEP recording, TCD cannot be recommended as a routine monitor in carotid surgery.

Aged↗
PubMed1994

[Cava filter for prevention of lung embolism: is implantation still justified?].

During a period of 11 years operative placement of a Greenfield vena caval filter was planned in 132 patients. The clinical records of these patients were reviewed retrospectively. Main indications for filter placement were pulmonary embolism in patients with deep venous thrombosis in spite of anticoagulation therapy (45%) and patients with contraindications for anticoagulation (40%). Insertion was successful in 117 patients with a failure rate of 14.6% (21 of 143 procedures). Follow-up data were obtained of all 117 patients with inserted filter (6 of them with 2 filters). Physical examination was performed in 67 of 74 patients alive after a mean postoperative period of 57 months (median: 52.5/range: 1-128). In addition, plain abdominal X-ray was available of all patients. CT scans of the abdomen or venacavography studies were obtained in 60 patients. Major complications as recurrent pulmonary embolism (8%), caval thrombosis (13%), penetrations of struts through the caval wall (33%), tilting of filters (25%), migration (5%) and filter fracture (two cases) were observed. In conclusion, indication should be restricted to certain cases with failure of surgical intervention or drug therapy (thrombectomy, lysis, anticoagulation).

Adult↗
PubMed1993

[Carotid endarterectomy in the elderly patient. Life table analysis and review of the literature based on 594 consecutive operations].

The significance of age as a prognostic factor was evaluated in patients undergoing carotid artery surgery between 12.8.86 and 31.10.92 in the Department of Vascular Surgery, Erlangen, 594 operations were performed on 546 consecutive patients using somatosensory evoked potentials as routine monitoring. Patients were divided into an older group of 139 (150 operations) with a mean age of 78.2 years and a younger group of 407 (444 operations) with a mean age of 64.4 years. There was no statistical difference in preoperative neurological status and number of risk factors, although there were different distributions of risk factors and concurrent illnesses. Thirty-day mortality rates were 1.7% for younger and 0.7% for older patients, and the incidence of postoperative stroke was 1.7% and 0.7% respectively (not statistically significant). Cumulative 5-year survival was 72.2% and 68.2% respectively. Cardiac diseases were the main cause of death in both groups, mainly fatal cardiac ischemia in younger patients and non-ischemic disease in the older patients. The 5-year stroke-free survival rate was 81% and 91.3% respectively (not significant). There was a trend towards a worse outcome for older patients with stages IIb and IV disease.

Adult↗
PubMed1993

Popliteal arteriovenous fistula after corrective upper tibial osteotomy.

Injuries to the popliteal artery or vein are rare complications of knee arthroscopy or osteosynthesis at the distal femur or the proximal tibia. We report a case of iatrogenic arteriovenous fistula after proximal tibial osteotomy for varus deformity. A 71-year-old woman complained of pain and swelling of the foot 9 weeks after a corrective barrel-vault osteotomy of the left tibia. Angiography demonstrated an arteriovenous fistula between the popliteal vessels due to osteotomy of the tibial head. The fistula was separated and popliteal vessels closed by continuous suture and a small saphenous vein patch.

Aged↗
PubMed1993

Tibial bypass grafting for limb salvage with ringed polytetrafluoroethylene prostheses: results of primary and secondary procedures.

PURPOSE: In advanced peripheral ischemia, tibial artery prosthetic bypass grafting is virtually the last chance for limb salvage when conservative treatment and other methods of revascularization have failed. METHODS: For this study we reviewed our 7 years of experience with below-popliteal artery polytetrafluoroethylene grafts implanted for limb salvage. RESULTS: All results regarding graft patency and limb salvage were computed by actuarial methods and were presented in the form of life-table analysis. There were 211 grafts in 184 patients (195 limbs). Two and 5 years after the operation, primary patency rates were 37% and 23% and secondary patency rates were 45% and 25%, respectively. The main negative predictive factors for patency rate were an occluded primary plantar arch artery and poor vessel runoff. Primary bypass procedures had markedly better success rates than secondary (repeat) procedures, with primary patency rates of 52% at 2 years and 42% at 4 years, whereas the corresponding rates for secondary procedures were 22% and 14%, respectively. The 5-year cumulative limb salvage rate was 51% for the total series. CONCLUSIONS: Although the patency of prosthetic grafts is not as satisfactory as that of autologous vein grafts, the limb salvage rate justifies an aggressive approach to infrapopliteal bypass grafting with polytetrafluoroethylene prostheses when the limb is threatened and vein is not available.

Aged↗
PubMed1992

[Hickman catheter for long-term parenteral therapy. A prospective interdisciplinary study].

160 patients with a median age of 38 years (range two months to 84 years) having silicone rubber central venous access catheters for long-term parenteral nutrition or chemotherapy were studied prospectively. Two different types of catheters were used, the Broviac-type "life-cath" and the Groshong -catheter. Intraoperative complications were not noticed. Parenteral therapy was performed in 124 patients (81%) without any complications. After a mean postoperative interval of 36 weeks there were 34 catheters removed because of end of therapy. 78 patients died with the catheter in place. 40 catheters had to be removed before end of therapy due to catheter-related complications. Occlusion of the lumen occurred in nine patients after an interval from three to 20 weeks. Explantation of catheters due to a suspected catheter-related sepsis was performed in 17 patients. Both types of catheter showed a high cumulative patency rate of 90% after a twelve months period. However, there were catheters that had to be removed before planned end of therapy. Thus, the cumulative rate of functioning catheters is lower (44% of all catheters).

Adolescent↗
PubMed1992

Monitoring during carotid surgery: somatosensory evoked potentials vs. carotid stump pressure.

In the following prospective study of 125 carotid endarterectomies, we compared monitoring of somatosensory evoked potentials (SEPs) with carotid stump pressure (CSP) measurement in order to determine the efficacy of both methods in reliably predicting cerebral ischemia caused by cross-clamping of the carotid artery. A complete flattening of the cortical SEP was the sole criterion for selective shunting. Two patients suffered from transitory neurological deficits in the postoperative period. Both experienced complete disappearance of postcentral SEP components after carotid cross-clamping. In a further 10 cases, an intraoperative loss of SEP amplitudes occurred, but could be reversed by the insertion of a shunt or by induced hypertension. All of these patients showed a normal neurological examination postoperatively as did all of the patients with identifiable SEPs after cross-clamping. In all of the 12 patients with complete flattening of the cortical waveform, we found CSP levels less than 50 mm Hg. A further 61 patients had a CSP less than 50 mm Hg, but neither an intraoperative loss of SEP amplitudes nor postoperative neurological deficits were detected in any of these patients. We conclude that, in contrast to CSP, SEPs not only help to identify patients with insufficient collateral blood flow who benefit from specific cerebral protection, but also to avoid improper and hazardous application of these measures in patients with sufficient cerebral perfusion.

Aged↗
PubMed1992

[Surgical indications--who determines the limits?].

The indication for revascularization in claudicants is determined by the complaints of the patients and the risk of the procedure. Instead of good long-term results, a possible more rapid progression of arteriosclerosis should be considered after a vascular procedure. In limb-threatening ischemia, a vascular intervention is possible in up to 95% of cases. In the case of poor prognosis, the patient himself decides whether or not amputation is the primary treatment. The consent of the patient is valid only when there is no possibility of revascularization as determined by objective criteria, or when the patient chooses amputation primarily. Therefore, the indication for amputation is not limited by the competence of a single surgeon.

Arterial Occlusive Diseases↗
PubMed1992

[Clinical significance of peripheral vascular resistance for early bypass occlusion rate. Errors and dangers in measuring vascular resistance].

An estimation of the peripheral resistance was performed during 264 peripheral bypasses. After completion of the distal anastomosis, saline was infused via the proximal graft end in constant flow rates. The mean distal pressure was used for calculation of peripheral resistance. There was a close correlation between the peripheral resistance (based on flow rates of 100 ml/min) and the 30 day graft failure rates. Below the level of 450 mPRU the failure rate was 4%, above 750 mPRU, however, this rate was more than 20%. It is concluded, that the estimation of the peripheral vascular resistance during the operation is a valuable tool to estimate the prognosis of graft patency.

Aged↗
PubMed1992

[Diabetic gangrene in peripheral vascular occlusion. Saving the extremity by popliteo-pedal venous bypass].

23 patients with diabetic gangrene and complete occlusion of all 3 tibial arteries were treated by 26 popliteopedal vein bypass grafts. All 6 early graft failures resulted in major amputations. The cumulative graft patency rate was 76% after 6 years. One patient needed lower-leg amputation despite a functioning graft. All other limbs were saved (mean follow-up period: 24.8 months). It is concluded that despite a palpable popliteal pulse an angiographic examination should be performed, when the infectious lesion cannot be controlled by local treatment and pedal pulses are absent.

Aged↗
PubMed1991

Investigations on the biochemical characteristics of chronically underperfused muscle.

During operation, biopsies from the gastrocnemius muscle and, in some cases, from the sartorius muscle were taken from 32 patients with peripheral arterial occlusive disease and from 5 subjects with normal peripheral circulation. In patients with inadequate circulation only during exercise, when compared with the control group, increased activities of enzymes involved in oxidative metabolism (malate dehydrogenase, nicotinamide adenine dinucleotide phosphate-dependent isocitrate dehydrogenase, cytochrome C oxidase, creatine kinase), in amino acid metabolism (asparate aminotransferase, alanine aminotransferase), and in anaerobic glycoysis (lactate dehydrogenase) were found. In patients with circulatory disturbances that manifested themselves already at rest, enzyme activities were, with the exception of LDH, lower than those of patients with exclusively exercise-related insufficiency. By means of intraindividual comparisons with the corresponding enzyme activities in the sartorius muscle, the author was able to show that the changes found were not simply the result of differences in training conditions. The diminished concentrations of energy-rich phosphate are an expression of the anaerobic metabolic state in patients with inadequate circulation at rest. It is concluded that chronic ischemia of muscle leads to changes in the energy metabolism of the cell. In the presence of more nearly adequate circulation at rest, the portion of oxidative potential of the total energy metabolism increases. In contrast, if there is an inadequate circulation at rest, the mainly anaerobic glycolysis becomes quantitatively predominant.

Amino Acids↗