NOTES (Natural orifice transluminal endoscopic surgery)

S. Uranüs, P. Kornprat, Section for Surgical Research & Division of General Surgery

The NOTES project is devoted to the development of new surgical methods involving endoscopic techniques. The minimization of surgical trauma with laparoscopy has shown how advantageous it is to avoid trauma to the abdominal wall. Twenty-two years’ experience with laparoscopic surgery as well as technical advances in interventional endoscopy both contributed to the old/new idea of using hollow organs with a natural external orifice as an approach for intraperitoneal procedures. In cooperation with outside partners, new manipulators using fluid actors suitable for NOTES are being developed to open a new dimension in minimally invasive surgery.

Multicenter randomized controlled study on patients with full thickness rectal prolapse

The study was completed in 2010 and the results published in Diseases of Coloproctology.

Virtual Patient

¹K.-M. Simonic, ²S. Uranüs

¹Institute for Medical Informatics, Statistics and Documentation, ²Section for Surgical Research & Division of General Surgery

The curriculum for a degree in medicine includes work with case studies and casuistry as the basis for problem-based clinical training. The starting point for case-based learning is a collection of representative case histories. To this end, data from different information and documentation systems will be selected, collected and anonymized and then processed for inclusion in electronic teaching systems. The aim is to develop a multimedia database that allows compact temporal presentation of the course of disease and treatment. The student plays the role of physician and is confronted with concrete situations requiring treatment of the virtual patient. In this way, students should be brought to the point where they make treatment decisions on the basis of what they have learned.

To realize this aim, typical cases in the form of mock-ups will be developed and analyzed in cooperation with the Section for Surgical Research. This will show how students make use of such a system, i.e., how they use this system under given circumstances, and how the system supports them in reaching defined aims. This information is important for the specification of requirements and to obtain a consensus between users and stakeholders on the desirable and/or necessary functional range

GLUMII (Subcutaneous glucose-monitoring with simultaneous insulin-infusion) - study for the I-Kath. Project

¹M. Hajnsek, ²T. Pieber

¹Joanneum Research, Institute for Biomedicine and Health Sciences Graz, Austria

²Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine

The I-Kath. project is carried out by the Health Institute of the Joanneum Research GmbH in cooperation with the Institute of Analytical Chemistry and Food Chemistry of the Graz University of Technology and the NTC Weiz.

The goal of the project is to develop an integrated catheter to determine glucose concentrations in subcutaneous tissue while insulin is infused simultaneously. As the novelty of the system is the use of one body interface for insulin infusion as well as for glucose measurement, this special system architecture is called “single port technology”.

The glucose concentrations in subcutaneous adipose tissue are detected by fluorescent dyes. They are excited transcutaneously by a light source located outside the body, and the fluorescent radiation is also recorded transcutaneously by a photo detector on top of the skin.

The close proximity of glucose monitoring and insulin delivery suggests an optional further step toward a closed loop system with implementation of an algorithm to predict insulin infusion rates depending on the recorded glucose concentrations.

Therapy- related myeloid neoplasia: in-vitro response to alkylating agents

¹J. Rankl, ¹K. Hiden, ²S. Uranüs, ³M. Horn, ⁴K. Flicker, ⁴M. Speicher, ¹H. Sill

¹Division of Hematology, ²Section for Surgical Research, ³Department of Dermatology, ⁴Institute of Human Genetics

Up to 15% of patients suffering from myelodysplastic syndrome and acute myeloid leukemia have a history of previous chemo- and/or radiotherapy for primary, malignant or non-malignant diseases. According to the WHO, these disorders are classified as therapy-related myeloid neoplasias (t-MN). The prognosis of patients with t-MN is poor, with long-term survival of less than 10%.

It is increasingly recognized that t-MN develops on the basis of genetic predisposition. In order to elucidate molecular mechanisms mediating initial steps of leukemogenesis, dermal fibroblasts from t-MN patients and matched healthy controls will be treated with active metabolites of the bifunctional alkylator cyclophosphamide and the response on the cellular and genetic level will be assessed.

Prospective randomized study of percutaneous cholecystectomy versus conventional cholecystectomy in patients with acute cholecystitis after heart surgery and heart-lung machine

¹H. Koller, ²S. Uranüs

¹Medical University of Graz, ²Section for Surgical Research

Acute cholecystitis is a common complication in coronary surgical intensive care. Pharmacological intervention, especially the administration of high dosages of catecholamine, antibiotics and analgesics, bears a risk of further complications which may then require further surgery. Current treatment options are cholecystectomy (CCE) and percutaneous cholecystectomy; CCE is at present the method of choice.

This study aims to compare the 30-day mortality rate of CCE versus PC and so to determine the optimal treatment in terms of survival.

Prospective multicenter study on conservative treatment of splenic injuries with blunt abdominal trauma

S. Uranüs, P. Kornprat, B. Salehi, G. Höbarth (Section for Surgical Research & Division of General Surgery)

This study examines the success rate of conservative treatment of splenic injuries as a function of severity. The aim is to determine the degrees of injuries for which nonoperative treatment is most suitable, and which concomitant injuries and diseases pose an increased risk. Five Austrian centers are involved, with Graz as study coordinator. The study was completed in 2010 and a publication is being prepared.

Orthotopic surgical implantation of human thyroid tumors in the athymic naked rat: A pilot study

¹O. Tsybrovskyy, ²D. Malliga, ¹M. Rößmann-Tsybrovskyy, ³G. Wolf, ³U. Gratzer, ⁴S. Uranüs, ⁵A. Kresse

¹Institute for Pathology, Graz, ²Division of Cardiac Surgery, ³Division of General Surgery, ⁴Section for Surgical Research, ⁵Institute for Pathophysiology and Immunology

There is particular interest in tumor research in animal models, especially xenografts of human tumors in rodents. They provide a unique chance to study tumors in vivo; for ethical reasons, this is usually not permissible in humans. These tumor models are commonly used to develop and test new chemotherapeutic agents. Immune-deficient mice are usually used as they do not reject tumor tissue, so allowing implantation of xenografts, particularly from human tumors.

Sacral nerve stimulation for incontinence

J. Pfeifer, D. Nagele-Moser, M. Y. Rigler (Section for Surgical Research & Division of General Surgery)

Etiologies of incontinence include damage to anatomical structures of the anus such as occult injuries to the anal sphincter upon vaginal delivery, stroke sequelae, diabetes mellitus, multiple sclerosis, Crohn’s disease and ulcerative colitis, as well as chronic inflammation and fistulas. Mild incontinence can usually be treated with diet, anti-diarrheal medication, pelvic floor exercises and biofeedback training. As an alternative treatment for nonresponsive incontinence, for the past seven years, the Division of General Surgery has applied stimulation to the relevant sacral nerves providing motor innervation to the anal sphincter and the pelvic floor. If incontinence improves after a two- to three-week phase of test stimulation, a permanent pacemaker is implanted and connected to a test electrode, so that the patient can resume a relatively normal life.

Stem cell treatment of fecal incontinence

J. Pfeifer, D. Nagele-Moser, A. Frudinger (Section for Surgical Research and Department of Obstetrics and Gynecology)

After a successful pilot project in which 10 patients received injections of stem cells into their anal sphincters, research continues on this treatment. The procedure is that patients who have a sphincter weakness due to muscle damage first receive a physiological workup. Patients who do not have additional nerve damage are eligible. Patients perform home training with electrostimulation. Muscle tissue is harvested from the axillary fold and cultured. These muscle stem cells are then implanted under ultrasonic guidance. The patients will be monitored clinically and physiologically.

Use of autologous thrombocyte-enriched fibrin to improve healing of chronic venous leg ulcer with simultaneous application of vagal stimulation with P-Stim™ to reduce pain and improve circulation

¹B. Binder, ²D. Nagele-Moser,  ²G. Tomasch, ³A. Berghold, ¹D. Kopera, ²S. Uranüs

¹Department of Dermatology and Venerology, ²Section for Surgical Research, ³Institute for Medical Informatics, Statistics and Documentation

Venous leg ulcer is the most serious form of venous insufficiency and is among the most common chronic diseases in the elderly, with approx. 1% of that age group afflicted. Treatment can take months or years. Infection and pain are frequent. Dressings must be changed regularly by health-care professionals and considerable material is needed. Local use of autologous fibrin can improve wound healing; it is commonly used in surgery to improve healing of inner organs. Theoretically, this effect would be even better if the autologous fibrin were enriched with autologous thrombocytes, but no data from controlled, randomized prospective studies are available to verify this. This study should further determine whether low-frequency auricular stimulation with the P-Stim™ device would improve circulation and in turn ulcer healing. Yet another aim is to ascertain whether electrostimulation, which leads to release of endogenous opioids, would lessen pain.

This study should determine which of these treatments is most effective in promoting fast, complete and lasting wound healing and so improving patients’ life quality, while at the same time reducing the costs of dressings and medical care.

Treatment of peripheral nerve lesions with an adaptive neuroprosthesis

¹G. Tomasch, ¹D. Nagele-Moser, ²D. Rafolt, ³ J. Waldert, ⁴ A. Berghold,  ⁵H. Koch, ⁵I. Justich, ⁶I. Wiederstein-Grasser, ⁷G. Bretthauer, ¹S. Uranüs

¹Section for Surgical Research, ²Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, ³Sigmund Freud Psychiatric Hospital, Graz, ⁴Institute for Medical Informatics, Statistics and Documentation, ⁵Division of Plastic and Reconstructive Surgery, ⁶Institute for Biomedical Research, ⁷Karlsruhe Institute of Technology

To date, satisfactory functional regeneration after traumatic transection of peripheral nerves could only be achieved with microsurgical coaptation, a specialized technique that can only be performed at centers with appropriate infrastructure. This study aims to develop a new reconstructive method using a synthetic prosthesis that does not require elaborate equipment but allows the same quality of treatment.

The ischiatic nerve will be severed in 35 female minipigs aged approx. 12 months. After randomization, 15 animals will receive the new neural prosthesis, 15 will be treated with microsurgical coaptation and 5 animals will serve as untreated controls. During the 10-month follow-up period, the animals will be monitored at 8-week intervals with electrophysiological studies to detect axon budding and sonography to evaluate muscle condition. Histopathological studies will be made at the end of the study period.

Results to date suggest that implantation of this neural prosthesis leads to good and effective regeneration and so could offer a new and simple option for the treatment of peripheral nerve lesions.

Attitude towards xenotransplantation of patients prior and after human organ transplantation

²V. Stadlbauer, ¹P. Stiegler, ³S. Müller, ²W. Koellner, ¹M. Schweiger, ¹M. Sereinigg, ¹KH.Tscheliessnigg, ¹Division of Transplantation Surgery, ²Division of Hepatology and Gastroenterology, ³Institute of Social Medicine and Epidemiology, Medical University of Graz

Xenotransplantation is a potential strategy to overcome the shortage of human donor organs. Since this technique has a major medical and psychological impact on patients and their family and friends, the attitude of patients currently waiting for an organ transplantation is important.

Therefore we conducted a survey on the attitude towards xenotrans-plantation of patients on the waiting list and already transplanted patients. Patients received detailed information before being asked to fill in the questionnaire.

We found that 65% would accept xenotransplantation, irrespective of gender, education level or if the patients were on the waiting list or already transplanted. The most common concern was transmission of diseases or genetic material, followed by psychological concerns and ethical issues. More patients had a positive attitude towards accepting cell or tissue transplantation as compared to whole organs. Pig pancreas islet cell transplantation is generally well accepted, patients with diabetes mellitus show even higher acceptance rates than patients without diabetes.

In conclusion xenotransplantation seems to be well accepted in patients who are potential future candidates for organ transplantation. Informing patients about the current status of research tended to decrease acceptance rates slightly.

Influences of the donor type on organ energy status: Living versus brain dead versus non-heart beating donor

¹V. Stadlbauer, *P. Stiegler, ¹P. Taeubl, *M. Sereinigg, *A. Puntschart, *A. Bradatsch, ²P. Curcic, *S. Uranitsch, ³T. Seifert-Held, ⁴T. Stojakovic, *B. Leopold, *D. Blattl,

*U. Mayrhauser, *B. Leber, ⁵G. Jürgens, *KH. Tscheliessnigg, ⁵S. Hallstroem

*Division of Transplantation Surgery, ¹Department of Internal Medicine Graz, ²Division of Cardiac Surgery, ³Department of Neurology, Graz, ⁴Clinical Institut for Chemical and Laboratory Medicine, ⁵Institute of Physiological Chemistry

Organs from living donors seem to have a better graft function after transplant-tation compared to organs from brain dead and non-heart beating organ donors. We hypothesized that brain death might impair the energy status of organs and therefore systematically evaluated high energy phosphate content in organs from living, brain dead and from non-heart-beating donors in a pig model. Our results showed that our hypothesis that brain death or cardiac arrest significantly impairs the energy status of donor organs did not hold true. The negative impact of brain death or cardiac arrest on graft function so cannot be attributed to changes in energy status.

Effect of oxidative stress and endotoxin on human serum albumin in brain-dead organ donors

*B. Leber, ¹V. Stadlbauer, *P. Stiegler, ¹S. Stanzer, *U. Mayrhauser, *S. Koestenbauer, *B. Leopold, *M. Sereinigg, *A. Puntschart, ²T. Stojakovic, *KH. Tscheliessnigg, ³K. Oettl

*Division of Transplantation Surgery, ¹Department of Internal Medicine, Graz, ²Clinical Institut for Chemical and Laboratory Medicine, ³Institute of Physiological Chemistry

Albumin binds and detoxifies endotoxin in healthy people. Oxidative stress leads to protein oxidation and thus to impaired binding properties of albumin. This, in combination with increased good permeability leads to appearance of endotoxin in systemic circulation and impaired organ function. We hypothesized that these processes occur in brain-dead organ donors. A study of 84 brain-dead organ donors categorized by length of ICU stay indicated that oxidative stress and systemic endotoxemia are present in brain-dead organ donors, which might affect recipient survival. High endotoxin levels might be due to increased gut permeability and decreased albumin binding capacity facilitated by higher albumin oxidation.

Establishing a Non-Heart-Beating Donor (NHBD) Model in pigs

P. Stiegler (Division of Transplantation Surgery)

Due to the lack of human donor organs, several strategies to expand the organ donor pool are under investigation. In recent years, great attention has been given to non-heart beating donors (NHBD) and a large animal model would be useful. We succeeded in establishing a NHBD pig model in our laboratory that will enable us to determine NHBD donor organ quality more precisely and to better evaluate storage conditions and donor treatment.

Establishing a brain death donor model in pigs

P. Stiegler (Division of Transplantation Surgery)

Several factors influencing organ quality and recipient survival after multiorgan donation and transplantation are still unknown and difficult to investigate in humans. . We established a brain death donor model in pigs that will enable us not only to investigate in detail effects and pathophysiology after occurrence of

brain death but also to evaluate new strategies to ameliorate organ quality and even to enlarge the donor pool for multiorgan donation.

A 10 min “No touch time” in Non-Heart Beating Donation – Is it enough?

²P. Stiegler, ¹V. Stadlbauer, ²M. Sereinigg, ²A. Puntschart, ³T. Seifert-Held, ²B. Leopold, ²D. Blattl, ²U. Mayrhauser, ²B. Leber, KH. Tscheliessnigg²

¹Department of Internal Medicine, Graz, ²Division of Transplantation Surgery, ³Department of Neurology, Graz

Non heart beating donation (NHBD) is under investigation due to the lack of human donor organs to expand the organ donor pool. The Maastricht criteria (I-V) are clear on this but difficult to put into effect. NHBD was simulated in 26 pigs to investigate brain activity after different times of cardiac arrest with successful CPR. The definition of EUROTRANSPLANT for a “no touch time” of 10 min of cardiac arrest seems to be sufficient to guarantee no brain as well as no brain stem activity. Shorter “no touch times” seem to be feasible but ethically not justifiable.

In vivo testing of biological agonists to the angiotensin receptor MAS

¹M. Schwarz, ¹H. Mueller, M. Lamacie (Brasilien), ²J. Greilberger, ¹KH. Tscheliessnigg,  R. Santos (Brasilien)

¹Division of Transplantation Surgery, ² Institute of Physiological Chemistry

The myocardium can tolerate short periods (up to 15 minutes) of total myocardial ischemia without causing cardiomyocyte death or reperfusion injury. Proposed contributory mechanisms include oxygen free radical formation, calcium overload, neutrophil–mediated myocardial and endothelial injury, progressive decline in microvascular flow to the reperfused myocardium, and depletion of high

energy phosphate stores. In this study, beneficial effects of various bioactive peptides will be tested, using a heterotopic rat heart transplantation model. Furthermore, protocols for clinical use are currently being designed.

Isolation and characterization of fetal and adult endothelial cells derived from different vascular beds

¹A. Schweizer, ²M. Schwarz, ²KH. Tscheliessnigg, ¹G. Dohr, ¹I. Lang.

¹Institute of Cell Biology, Histology & Embryology, ²Division of Transplantation Surgery

The endothelial cell lining of the inner surface of blood vessels represents a metabolically active tissue with a wide range of functions relating to vascular homeostasis.

We established a method for the isolation of arterial and venous endothelial cells from different human vascular beds to 1) study organ-specific differences, and 2) compare the phenotype of fetal and adult endothelial cells.

Further, we investigated the effects of hypoxia on the morphological characteristics, the viability and the proliferative activity of fetal and adult endothelial cells.

Adult arterial and venous endothelial cells (a-AEC and a-VEC) were isolated from different vessels of organ donors; fetal arterial and venous endothelial cells (f-AEC and f-VEC) were obtained from the placenta by gentle perfusion of the resected vessels with an enzymatic solution containing collagenase II.

Our data prove the heterogeneity of human fetal and adult VEC and AEC derived from different human vascular beds cultured under normoxic and hypoxic conditions.

The effects of hypoxia on the differentiation potential of endothelial cells will be the objective of further studies.

Impact of chronic treatmemt with Sanopal® on the severity of cyclosporine A-induced nephropathy and on cardiac function in rats

¹M. Schwarz, ²T. Wiener, ²R. Arnold, ²E. Hofer, ³J. Greilberger, ⁴A.  Meinitzer,

¹S. Schaffer, ⁵I. Lang, ¹KH. Tscheliessnigg

¹Division of Transplant Surgery, ²Institute of Biophysics, ³Institute of Physiological Chemistry , ⁴Institute for Chemical and Laboratory Medicine, ⁵Institute of Histology and Embryology

Transplantation of non-renal organs is often complicated by chronic renal failure due to multifactorial causes. Calcineurininhibitor therapy (e.g. Cyclosporine A), a key component of the immunosuppressive regime for patients after allograft transplantation, has been implicated as a principal cause of post-transplantation renal dysfunction, which leads to severe tubular atrophy, interstitial fibrosis, and focal hyalinosis of small renal arteries and arterioles. There is an undeniable link between kidney dysfunction and cardiovascular risk. Furthermore, the cardiovascular risk is increased very early in the evolution of chronic kidney disease (CKD) (at a GFR of about 75 ml/min) and increases continuously with decrease in renal function. Increased levels of oxidative stress markers are present in the plasma of CKD patients, which indicates that uremia is a pro-oxidant state. In the present study the chronic effects of Sanopal® treatment on kidney function in Cyclosporine A-induced renal failure will be evaluated. In addition the hearts will examined to see if and to what extent (biochemical, histological, and physiological levels) the cardiac function in uremic rats subjected to Cyclosporine A induced nephropathy with and without simultaneous Sanopal® treatment, is impaired.

Retrospective analysis of cell turnover in the human heart

¹Sofia Zdunek, ¹Olaf Bergmann, ²Michaela Schwarz, ¹Jonas Frisen

¹Karolinska Institute, Stockholm, ²Division of Transplant Surgery

The ability of myocardial cells to regenerate in the adult mammalian heart has been a subject of controversy over the past decades. This is because traditional methods used for dating cells are limited in the information they provide, or are not appropriate for human use. Thus, there is no method currently available for studying cell turnover in man. We have developed a strategy by which we are able to retrospectively determine the birth date of cells in adult human hearts. The first study performed focused on the regeneration in the healthy human heart, the ongoing study investigates pathological hearts. (not used for transplantation)

EuroSTEC: Soft tissue engineering for congenital birth defects in children: from "biomatrix - cell interaction - model system" to clinical trials

A. Saxena

The EuroSTEC project is based on tissue engineering and regenerative medicine. The problems of organ shortages are more acute in the pediatric age group than in the adult population; this is largely because of the organ size mismatch between adult donors and pediatric recipients. Major syndromes affecting multiple organs present additional co-morbidities in congenital malformation syndromes and offer an altered environment for the biomaterial or engineered tissue. The manifestation of a particular congenital malformation affecting an infant varies to a large extent and depends on the severity of the defect, type of organ affected and to the existence of concomitant medical conditions.  Since research in the field of tissue engineering and regenerative medicine has a trend towards focus towards specific organs, EuroSTEC research has focused on soft organs and their multiplicity of involvement in congenital malformation.

GIDEON II- Arterial blood glucose measurement in porcine model

¹E. Svehlikova, ¹A. Tuca, ¹E.M. Pichler, ¹B. Kiefer, ¹S. Korsatko, ²G. Bauer, ²M. Pösinger, ² H. Köhler, ^1,2 M. Ellmerer, ¹T.R. Pieber

¹Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine, ²BBraun, Melsungen, Germany As studies have shown that blood glucose normalisation in critically ill patients can improve clinical parameters like morbidity and mortality, a substantial effort has been made toward the development of glucose sensors that can be efficiently and safely used in intensive care. In order to fulfil the high safety and quality demands it is also necessary to prove the stability and accuracy of these sensors before they are introduced into the clinical setting.

The objective of the experiment was to test the improved >TG+ concept< with regard to accuracy and stability. The experiments with the glucose sensors were performed in porcine model in whole blood under conditions close to intended use.

The TG+ sensor (© BBraun) was evaluated in 10 healthy pigs during a 10-hour glucose clamp experiment with alternating target glucose concentrations (normo-, hypo- and hyperglycaemia) and alternating target arterial oxygen tension (normo-, hypo- and hyperoxemia).

The results of the present study will help to develop the system and to make it available for clinical use.

Mild hypothermia for the treatment of acute ischemic heart failure

¹H. Post, ²H. Mächler, ²S. Huber, ¹Michael Schwarzl, ¹B. Pieske

¹Division of Cardiology, ²Division for Heart Surgery

Induction of mild hypothermia (MH, 33°C) is the first treatment option that can effectively reduce the degree of hypoxic brain damage after cardiocirculatory arrest and as such was included in intensive care guidelines in 2005. With a pig model, we showed that MH increases inotropy in both healthy and reanimated hearts (left shift of the pressure/volume ratio) and decreases total oxygen demand by 6%. Spontaneous bradycardia compensates for a simultaneous diastolic dysfunction. In a further experimental series, we showed that MH also improves the total oxygen balance during acute ischemic heart failure induced with coronary microembolization. The small cardiac output during MH is more than compensated for by the pronounced decrease in total oxygen demand. Further, a critical decrease in average aortal pressure is prevented. Induction of MH could be a treatment option for acute ischemic heart failure and cardiogenic shock as such.

Minimally invasive extracorporeal circulation (MECC) versus conventional extracorporeal circulation (heart-lung-machine/HLM) – a heart surgery study in small animals

*I. Ovcina, *P. Curcic, *A. Koköfer, *M. Erker, *R. L. Kupsa, *D. Dacar, ¹J. Krumnikl, ²K. Pfurtscheller, *H. Suppan, ³M. Cajlakovic, ³V. Ribitsch, *KH. Tscheliessnigg, *I. Knez

*Division of Heart Surgery, ¹Division of Anesthesiology, ²Pediatric Department, ³Joanneum Research, Karl-Franzens-Universität Graz

Only very recently, a new system was developed, a miniaturized model of the HLM (heart-lung-machine), the MECC system (minimally invasive extra-corporeal circulation), or “resting heart system.” This is a minimal, closed extracorporeal circulation system with a Carmeda® Bioactive Surface on all of its components.

The MECC promises the following advantages which, however, have proved difficult to verifiy in randomized clinical studies: Carmeda® coating, no blood-air contact (closed system), minimal hemolysis, small priming volume, higher hematocrit values, no need of allogeneic blood transfusion, lower lactate values.

Our results so far indicate that photochemical probes to measure oxygen and CO₂ partial pressure in the central nervous system, myocardium and liver parenchyma during extra-corporeal circulation are highly promising to objectively determine metabolic shifts and differences in tissue oxygenation. In a further study, we will attempt to adapt our minimodel for use with small experimental animals (up to 10 kg). This will present a considerable challenge from the points of view of technology (different oxygenators from different manufacturers) and methodology (there is no minimodel of this sort anywhere in the world for use in cardiac surgery on children with congenital heart defects).

Ideal flow geometry in bypasses

¹H. Mächler, ¹K. Meszaros, ²R. Rienmüller, ³G. Leitinger, A. Vötsch C.m.

¹Division of Cardiac Surgery, ²Department of Radiology, ³Core Facility Ultrastructure Analysis

An animal model with New Zealand white rabbits analyses the flow geometry of different curved bypass courses with a special MR technique.

The abdominal aorta is approached retroperitoneally via a lateral thoracotomy, clamped and anastomosed end-to-end with the aorta of another rabbit in one of the curved courses to be examined (the curve is calculated in advance and marked with a three-dimensional template). The flow profiles are visualized and analyzed, and after three months the aorta is removed for histological study.

This should make it possible to determine the ideal bypass course that approximates nature in its flow geometry. The information obtained will be applied to patients undergoing bypass surgery and will be further evaluated.

CNP Suprasorb study using an animal model

T. Auer, M. Rigler, A. Wels (Division of General Surgery)

The experimental series of 7 domestic pigs was terminated successfully and the evaluation completed.

After the animals had undergone abdominal hypobaric treatment for 8 hours, the effects of the film in the abdomen were examined macroscopically and histologically. The application sites – liver, pancreas, small intestinal anastomosis and colon suture – were undamaged and the intestinal sutures showed a healing tendency. Histologically, the organs and the walls of the intestines were free of microcirculatory damage or other changes.

On the basis of these positive results, a study on patients was begun in June, 2010, whereby individual results confirm the experience with the animal model.