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Biomedical subjects

M Weyand

Publications and source records attributed to M Weyand.

At least 19 recordsLinked to original sources
PubMed2006

Congenital coronary artery fistula draining into the right ventricle: successful surgical closure after failed transcatheter coil embolization.

Coronary artery aneurysms and fistulae are very rare congenital anomalies. They occur in 0.2-0.4 % of all congenital heart diseases. In this article, we report a case of a four-year-old girl with a right coronary artery aneurysm and fistula draining into the right ventricle. Since the transcatheter coil embolization was not successful, surgical occlusion was considered in this case. We describe and discuss the handling of the fistula and the aneurysmatic enlargement of the proximal coronary artery.

Cardiac Catheterization↗
PubMed2006

Does the additional use of heparin-coated extracorporeal circuits (ECC) optimize the effect of modified ultrafiltration (MUF) in pediatric perfusion?

BACKGROUND: Modified ultrafiltration (MUF) has been shown to exert beneficial effects on the coagulation system and the capillary leak after pediatric cardiac surgery using extracorporeal circulation (ECC). The aim of this study was to investigate whether the additional use of heparin-coated circuits is a useful option for improving biocompatibility. METHODS: We randomized 28 children, using heparin-coated ECC circuits in group A (n = 14) and an uncoated equivalent set in group B (n = 14). After congenital heart surgery, MUF was performed post ECC in a standardized fashion. Blood samples were analyzed preoperatively, 10 min, 30 min, 1 h, and 48 h after ECC by flow cytometric analysis (FACSort) using surface antigens CD62/CD41b (platelets) and CD45/CD14 (monocytes). RESULTS: No significant difference was found with respect to mean age (20.6 months vs. 21.6 months), mean body weight (9.2 kg vs. 8.4 kg), mean ultrafiltration rate (9.1 ml/kg vs. 11.4 ml/kg), chest tube drainage, blood products, ICU stay, and 30-d survival. The percentage of CD62/CD41-positive platelets in group A (vs. B) increased up to 118 % at 60 min vs. 130 % ( P < 0.05) and declined to 98 % at 48 h postop. vs. 99 % (n. s.). The percentage of CD45/CD14-positive monocytes in group A (vs. B) increased up to 158 % at 60 min vs. 155 % (n. s.) and declined to 122 % (A) at 48 h postop. vs. 61 % (B) ( P > 0.05). CONCLUSIONS: Heparin coating of ECC in addition to MUF leads to a lower platelet activation. Monocyte surface markers CD45 and CD14 indicated a marked activation during ECC in both groups but additional heparin coating showed a better postoperative regeneration of monocyte markers in the late course indicating a beneficial additive effect.

Antigens, Surface↗
PubMed2006

[The importance of vacuum therapy in the treatment of sternal osteomyelitis from the plastic surgeons point of view].

BACKGROUND: Since its introduction in 1997 the vacuum assisted closure therapy has gained widespread and is for its indications international accepted. It is also well established in the treatment of sternal infections a dreaded complication after median sternotomy in cardiac surgery. The well known positive effects of the vacuum therapy act as a dignified cleaning procedure between debridement and plastic coverage or as a temporarily closure method if the first debridement was properly not sufficient. METHOD AND PATIENTS: Between January 2003 and December 2005 twenty eight patients with advanced sternal infection after median sternotomy were treated by radical debridement, vacuum assisted closure therapy and definitive plastic coverage by muscle flaps. In this article three patients are exemplarily introduced. RESULTS: In all patients a sufficient plastic coverage was achieved after radical debridement an vacuum assisted closure therapy. The patients received a pedicaled muscle flap. Stable wound condition with no signs of a recurrent sternal infection were observed in all patients. DISCUSSION: Vacuum assisted closure therapy acts as a link between radical Debridement and definitive plastic coverage in prolonged sternal infection after median sternotomy. Before the invention of V.A.C.(R) dressing changes were obliged every day in patients with deep sternal infection. The V.A.C.(R) therapy reduces the frequency of this painful dressing changes significantly and on this behalf makes life more comfortable for this mostly multi-morbid patients.

Aged↗
PubMed2006

[Computer-assisted process simulation: a suitable instrument for process optimization in hospitals].

The increasing financial pressure on hospitals resulting from changes in the health system demands detailed knowledge about the cost and earnings situation in the hospital. An essential part of strategic controlling now entails establishing structured cost-unit accounting. This can then be used for example through process optimization to ascertain savings potential and rationalization measures. This paper illustrates a possibility of using computer-assisted process simulation to find ways for prozess optimization. The simulation has been based on the treatment process "operative procedure" of a clinical pathway "CABG" developed in our hospital. The starting points for simulation possible prozess optimization consisted in the elimination of existing waiting times, respectively the parallel organization of certain partial processes. The software used for the simulation was Coral iGrafix Process 2003. The results of 1000 simulation processes reveal a clear reduction in the whole lead-time for the patient, both in avoiding waiting times and also in parallel process organization. In contrast to the initial situation (triangular distribution), the overall duration of the treatment section can be described approximately with normal distribution and a clear cluster of minimum overall durations. Computer-assisted process simulation is a suitable instrument for revealing and establishing possibilities for process optimization in hospitals, and therefore makes a valuable contribution to strategic controlling.

Cardiac Surgical Procedures↗
PubMed2006

Good ecological status in a heavily urbanised river: is it feasible?

In Germany, a national instructions sheet, BWK M3, sets out how the impact of sewer system discharges on receiving water bodies is to be analysed. When applying the simplified assessment procedure defined therein and relying on traditional measures only, it becomes evident that in heavily urbanised rivers a large number of retention facilities would be needed to improve the hydraulic and qualitative conditions. However, the associated economics make the feasibility of such an immission-based approach to river restoration doubtful. In response, the Bergisch Rheinischer Wasserverband and the Ruhrverband started a common research project to find out whether and how the Rinderbach River, a heavily modified water body in terms of morphology and flow dynamics, could achieve the good ecological status required under the European Water Framework Directive. The focus of the survey was on the elaboration of an inventory, the identification of potentially attainable ecological objectives, and the discussion of measures with regard to their benefits and feasibility. The results obtained clearly show that it is possible to achieve good ecological status in already heavily urbanised rivers by making use of all existing natural potential within the river basin. They also demonstrated that a good interactive co-operation of experts in the fields of biology, urban drainage and hydraulics is indispensable.

Conservation of Natural Resources↗
PubMed2006

Cost-efficiency aspects for fish passage restoration in the Ruhr River Basin.

The protection and sustainable management of the aquatic ecosystems is the central aim of the European Water Framework Directive. Due to the aspiration for good ecological status of the water bodies free fish passage will play an important part in river basin management. The Ruhr River has seen severe anthropogenic modifications due to urbanisation and industrialisation in the 19th and 20th centuries leading in the existence of approx. 1300 weirs within the Ruhr River Basin. The majority of the barriers are assessed as not passable or restricted passable. Against this background the Ruhrverband made a holistic approach towards restoring fish passage within the Ruhr catchment. Besides the scientific and technical aspects, such as the determination of potential (spawning) habitats and the development of measures in order to reach them, they also considered cost-benefit-ratio considerations for the Ruhr catchment as a whole as well as for site-specific designs of fish passage structures. Various benefits were evaluated taking into account different fields of economic interest. The model of financing all necessary measures should involve all responsible parties benefiting from the water utilizations. Such a mutual procedure delivers a fair cost distribution as well as an efficient implementation of measures.

Animal Migration↗
PubMed2005

Structural and mechanistic insights into the interaction between Rho and mammalian Dia.

Formins are involved in a variety of cellular processes that require the remodelling of the cytoskeleton. They contain formin homology domains FH1 and FH2, which initiate actin assembly. The Diaphanous-related formins form a subgroup that is characterized by an amino-terminal Rho GTPase-binding domain (GBD) and an FH3 domain, which bind somehow to the carboxy-terminal Diaphanous autoregulatory domain (DAD) to keep the protein in an inactive conformation. Upon binding of activated Rho proteins, the DAD is released and the ability of the formin to nucleate and elongate unbranched actin filaments is induced. Here we present the crystal structure of RhoC in complex with the regulatory N terminus of mammalian Diaphanous 1 (mDia1) containing the GBD/FH3 region, an all-helical structure with armadillo repeats. Rho uses its 'switch' regions for interacting with two subdomains of GBD/FH3. We show that the FH3 domain of mDia1 forms a stable dimer and we also identify the DAD-binding site. Although binding of Rho and DAD on the N-terminal fragment of mDia1 are mutually exclusive, their binding sites are only partially overlapping. On the basis of our results, we propose a structural model for the regulation of mDia1 by Rho and DAD.

Amino Acid Motifs↗
PubMed2005

Systematic assessment of atypical deletions reveals genotype-phenotype correlation in 22q11.2.

INTRODUCTION: Clinical variability associated with the common 22q11.2 microdeletion is well known, and has led to a broad application of FISH diagnostics with probes for loci TUPLE1 or D22S75 (N25), although, rarely reported atypical deletions associated with the same phenotypic spectrum would not be discovered by these probes. As most types of 22q11.2 deletions occur between low copy repeats within the region (LCR22), we assumed that atypical deletions should be more common than has been reported. To address this question and the possibility of a deletion size related genotype-phenotype correlation, we systematically assessed the frequency of typical and atypical 22q11.2 deletions in a large cohort of patients. METHODS: We used a set of 10 fluorescent in situ hybridisation (FISH) DNA probes, capable of detecting all reported and hypothetical deletions between the LCR22, and analysed 350 patients. Deletion sizes in atypical deletions were established by use of further FISH probes. Frequency of certain atypical deletions was analysed in controls by FISH and quantitative PCR. RESULTS: Patients with conotruncal heart defects (ctCHD) and with typical VCFS phenotype showed the common 3 Mb or nested 1.5 Mb deletions (in 18.5% and 78.6%, respectively), but no atypical deletion, while 5% (3/63) of patients with a mildly suggestive, atypical phenotype showed atypical distal deletions, which were not detected in patients with mental retardation of unknown origin or in healthy controls. DISCUSSION: These statistically significant differences demonstrate that atypical distal 22q11.2 deletions are very uncommon in patients with ctCHDs, while atypical congenital heart defects and mild dysmorphism are recognisable feature of atypical distal deletions. Further phenotype-genotype analysis disclosed association of significant developmental delay with the distal part of the common deletion region, and choanal atresia and atypical CHDs with the adjacent distal deletion region.

Chromosomes, Human, Pair 22↗
PubMed2005

Cost unit accounting based on a clinical pathway: a practical tool for DRG implementation.

Setting up a reliable cost unit accounting system in a hospital is a fundamental necessity for economic survival, given the current general conditions in the healthcare system. Definition of a suitable cost unit is a crucial factor for success. We present here the development and use of a clinical pathway as a cost unit as an alternative to the DRG. Elective coronary artery bypass grafting was selected as an example. Development of the clinical pathway was conducted according to a modular concept that mirrored all the treatment processes across various levels and modules. Using service records and analyses the process algorithms of the clinical pathway were developed and visualized with CorelTM iGrafix Process 2003. A detailed process cost record constituted the basis of the pathway costing, in which financial evaluation of the treatment processes was performed. The result of this study was a structured clinical pathway for coronary artery bypass grafting together with a cost calculation in the form of cost unit accounting. The use of a clinical pathway as a cost unit offers considerable advantages compared to the DRG or clinical case. The variance in the diagnoses and procedures within a pathway is minimal, so the consumption of resources is homogeneous. This leads to a considerable improvement in the value of cost unit accounting as a strategic control instrument in hospitals.

Accounting↗
PubMed2005

The use of preoperative intra-aortic balloon pump in open heart surgery.

AIM: Intra-aortic balloon pump (IABP) therapy before open heart surgery has been suggested for ''high risk'' patients. METHODS: Records from patients undergoing open heart surgery at our institution between June 1999 and February 2002 were reviewed. Indication for IABP insertion was severely impaired left ventricular function, acute myocardial infarction (MI) or unstable angina. RESULTS: Fifty-five patients were included in the study: 41 male, 14 female, age 64+/-9 years. Fifty-one (92.7%) required coronary artery bypass brafting (CABG) alone or as a combined procedure, 2 (3.6%) required mitral valve surgery, and 2 (3.6%) needed more complex cardiac procedures. Thirty-two patients (58%) underwent emergency cardiac surgery and 11 patients (20%) suffered from acute preoperative MI. The overall 30 days mortality was 9%. Mean intensive care unit (ICU) stay was 6+/-8 days. Four patients (7.2%) developed postoperative renal failure requiring temporary hemodialysis. Three patients (5.4%) developed IABP related peripheral vascular complications. CONCLUSIONS: Perioperative morbidity and mortality is increased despite preoperative IABP, particularly in patients with acute MI. In contrast to studies not using this approach, preoperative IABP reduces morbidity and mortality of high risk patients. IABP related complications are low. Our data suggest that high risk patients profit from preoperative IABP therapy, however, prospective studies are needed to confirm these findings.

Cardiac Surgical Procedures↗
PubMed2005

Restoration of fish passage: development and results of a master plan established for the Ruhr River Basin.

According to the central aim of the European Water Framework Directive, the protection and sustained management of the aquatic ecological system, the ecological condition of a specific type of water, will be the primary parameter in future. Aiming at good ecological status in surface water bodies, population diversity and abundance of fish and macroinvertebrates is decisive. Free passage in river systems, to allow the natural migration of fish and all other aquatic organisms, is a prerequisite. To achieve this for the Ruhr River Basin a study has been commissioned in order to develop a master plan for river continuum restoration. Sustainable development aimed at promoting biodiversity in the surface water body system is a key objective. This project is complemented by investigations of the sediment--which is the nursery of the fish--in the rivers to identify river sections or tributaries which obviously provide a suitable habitat for the successful reproduction of big Salmonidae. The master plan illustrates the inherent problems of projects aimed at the restoration of fish passage in water bodies which are strongly affected by anthropogenic modifications. The results obtained may as well be transferred to other catchments with similar use patterns.

Animals↗
PubMed2004

The Impella Recover microaxial left ventricular assist device reduces mortality for postcardiotomy failure: a three-center experience.

BACKGROUND: We evaluated patient outcomes and complications associated with the microaxial Impella Recover left ventricular assist device (Impella Cardiosystems AG, Aachen, Germany) for postcardiotomy low-output syndrome. This low-cost device is inserted across the aortic valve through a 10-mm vascular graft sewn to the ascending aorta. METHODS: Impella patients were compared with 198 patients treated with an intraoperative intra-aortic balloon pump between January 2000 and December 2002. Three risk scores were used: the Hausmann score, the Texas Heart Institute score, and the Cleveland intensive care unit score. Between September 2001 and March 2003, 24 patients were treated with the Impella Recover for low-output syndrome. Before device insertion, 21 could not be separated from cardiopulmonary bypass, and 3 had postoperative hemodynamic instability despite high-dose catecholamines. Sixteen were treated with the Impella and intra-aortic balloon pump and 8 with the Impella alone (no intra-aortic balloon pump because of peripheral vascular disease or because deemed unnecessary). RESULTS: No technical problems with device insertion occurred. Pump flow was 3.3 +/- 0.7 L/min at 28,000 +/- 4500 RPM. Support time was 61 +/- 56 hours (range, 7-228 hours). Four devices required repositioning. One device failed (leaking purge line) and was removed. Hemolysis was minimal (lactate dehydrogenase levels of 540 +/- 260 U/dL for Impella survivors). Mortality for Impella patients was 54% (13/24), similar to that for high-risk intra-aortic balloon pump patients (Hausmann score > or =2 [57%], intensive care unit score > or =2 [51%], Texas Heart Institute score > or =0.75 [55%], and cardiac index < or =2.3 [45%]). Cardiac output data were available in 19 Impella patients. Impella patients able to increase their cardiac output to 1 L/min or more above the pump flow of the Impella Recover had a 10% (1/10) mortality, versus 88% (8/9) in patients with a residual cardiac function of 1 L/min or less (P =.001). Comparison of high-risk intra-aortic balloon pump patients with Impella patients with residual cardiac function of 1 L/min or more showed a significant reduction in mortality, regardless of the high-risk definition used. Residual cardiac function was the strongest predictor of survival in Impella patients. CONCLUSIONS: The Impella Recover device provides 3 to 4 L/min flow. It improves survival in patients with low-output syndrome if the heart is able to pump 1 L/min or more above device flow.

Aged↗
PubMed2004

Late pulmonary valve replacement after correction of Fallot's tetralogy.

BACKGROUND: The aim of this study was to investigate necessity and outcome of late pulmonary valve replacement (PVR) after repair of tetralogy of Fallot (TOF). METHODS: Hospital records from patients operated on for TOF at our institution between 1960 and 2002 were reviewed and patients were interviewed by questionnaires. RESULTS: Out of 411 long-term survivors after TOF-repair, 47 (11.4 %) patients required reoperation after 13.2 +/- 7.4 years. Preoperative right ventricular (RV) dilatation was present in 36 (76.6 %) patients including 16 (34 %) with impaired RV function. Isolated PVR was performed in 12 patients (25.5 %). Additional procedures were necessary in 35 patients (74.5 %), including closure of residual defects (VSD, n = 11), tricuspid valve replacement (n = 1) and repair (n = 3). Obstructive right ventricular or pulmonary artery lesions (34 patients, 72.3 %) were all surgically addressed. RV pressure decreased from 61.1 +/- 27.7 to 42.9 +/- 13.3 mm Hg (p < 0.01) after PVR. RV size was reduced and RV function improved compared to preoperative values. Early mortality after reoperation was 2.1 % (n = 1) with one patient dying from biventricular failure. There was no late mortality. CONCLUSIONS: PVR after Fallot repair is frequently required because of progressive RV enlargement with dysfunction. It can be performed with relatively low risk, even in the setting of multiple reoperation. Obstructive lesions (RVOTO, PA stenosis) and residual defects are frequently observed in patients needing late PVR and may play a crucial role in the development of RV failure. Timely valve replacement with repair of all obstructive lesions proximal and distal to the implanted valve is the key to preserving RV function.

Adolescent↗
PubMed2003

Measures for structural improvement with regard to the good status of water bodies--estimation of expenditure for a river basin in Germany.

To achieve the objective of "good chemical and ecological status" in water bodies as stipulated by the European Water Framework Directive (WFD) in particular, a package of measures geared to improving the water bodies' hydromorphology will be required. These upgrading measures can, to some extent, also be seen as an alternative to still more advanced measures in the field of wastewater treatment and stormwater treatment in the context of status improvement in water bodies. On account of the very high level of wastewater and stormwater treatment already achieved, additional efforts in this specific area would, as experience has shown, not only be extremely costly, but produce just moderate if not minor results. In an estimate of the funding required to achieve "good status" by hydromorphological change, undertaken for the Ruhr River Basin (German state of North Rhine-Westphalia), it was found that costs would be in the range of [symbol: see text] 200 million to [symbol: see text] 1 billion. This translates into inhabitant-specific costs of [symbol: see text] 100 to [symbol: see text] 500 per capita. All measures are to be put into practice within the scope of an integrated water body development concept, optimised with regard to space and time.

Costs and Cost Analysis↗
PubMed2002

[Incidence and prevalence of postoperative acute confusion in heart surgery patients after coronary artery bypass and heart valve replacement surgeries].

Compared to foreign countries, Germany does not have data about the occurrence of acute confusion following heart-surgery. However, the occurrence of acute confusion does extend the hospital length of stay for up to 13 days. Thus, this phenomenon is of high relevance to nursing. This prevalence/incidence study was implemented with the goal of obtaining exact information on the incidence rate of acute postoperative confusion after a heart surgery through a multicenter evaluation. The data evaluation took place in the form of a convenience sample survey in three different German clinics specializing on heart surgeries. The observation period lasted from the day of the surgery up to the fifth postoperative day. In the context of this prospective Cohort-study all patients aged 18 and older who had heart surgery between February 1st and April 30th, 2000, were considered suitable as participants in the study. In the end, 860 patients were included in this study. 152 patients (17.4%) showed symptoms of acute confusion (confidence interval 14-20%). Certain circumstances seemed to predispose patients to acute confusion. A widespread occurrence could be observed particularly at night. Patients aged 81-91 were mainly affected. A confusion rate of 43.5% could be determined for this group. These results confirm the clinical importance and suggest interdisciplinary approaches for solution.

Adult↗
PubMed2002

The influence of stormwater treatment on the hydraulic and pollution load--balance for an entire river basin.

The installation of about 500 stormwater detention facilities (SDFs) led to a significant drop of the pollution originating from stormwater runoff in the river basin of the Ruhr which covers 4,488 km2. The German technical directives on the design of SDFs are briefly outlined and the specific costs for such plants are given. The average costs for one kilogram COD held back by SDFs in combined systems amount to Euro 3.73 (calculated without consideration of the subsequent removal in the municipal wastewater treatment plant (WWTP)). The tank volume for stormwater storage can be minimised by application of real-time management systems which allow a dynamic operation of all SDFs in a catchment area.

Cities↗