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Biomedical subjects

P Brenner

Publications and source records attributed to P Brenner.

At least 19 recordsLinked to original sources
PubMed2002

Abdominal wall and foot reconstruction after extensive desmoid tumor resection with free tissue transfer.

BACKGROUND: Desmoid tumors are rare connective tissue tumors, also referred to as deep, aggressive fibromatosis. Although histologically benign, they show an invasive growth behavior and have a high local recurrence rate. METHODS: The treatment of choice is surgical resection with wide negative margins, while the use of radiotherapy remains controversial. Wide resection of greater desmoid tumors may result in considerable defects and functional impairment. Few papers discuss different options for defect coverage after desmoid tumor resection. Two cases of extensive desmoid tumors, one at the trunk, one at the foot, both with compromised wound margins due to multiple previous surgeries, are presented. To achieve a stable and functional soft tissue cover, the defects were treated with microvascular soft tissue transfer (one free latissimus dorsi, one free radial forearm flap). RESULTS: Both flaps healed uneventfully and patients regained full function of the abdominal wall and foot, respectively. CONCLUSIONS: The presented cases demonstrate the efficacy of free flap coverage as an ultimate therapeutic option in selected cases of critical defects after extra-abdominal desmoid tumor resection. Furthermore, free flaps provide a well vascularized ground for adjuvant radiotherapy.

Adult↗
PubMed2002

[Decubital ulcer--causes, surgical therapy and prognosis].

7.6 % (n = 134/1 769) of all inpatients in Leuven, but 30.1 % of risk patients suffer of pressure sores (Norton Scale 10.4 points). Predisposed are geriatric patients or those of intensive care units. While fasciocutaneous flap likewise the superior gluteal artery perforator flap are more resistant to mechanical forces, myocutaneous flaps are the working horse for pressure sores with deep-tissue pockets or osteitis (Campbell stage > IV). Partial resection of the median sacral crest or ischiectomy are obligatory. In analyzing a 16 years period only 33 percent of myocutaneous flaps healed uneventful, while due to multiple enumerations more than 50 percent presented complications. Partial flap and complete necrosis happened in 6 respectively in 2 percent. Rectus abdominis myocutaneous flap reconstruction as well as the free tissue transfer are useful alternatives to hip disarticulation with total thigh flap coverage or a complete fillet flap of the lower extremity. Independently of the selected closure 50 percent of all decubitus patients will develop recurrences in longterm follow up. Thus prevention is of utmost importance. In Europe the costs for the hospitalisation of a patient with concomitant decubital ulcers are 2.5-times higher than for an average, non-afflicted patient.

Humans↗
PubMed2001

[Dupuytren contracture in North Germany. Epidemiological study of 500 cases].

Dupuytren's disease is the "classical" hand illness of the north: it affects people of Celtic or Viking descent throughout the whole of northern Europe, whereas it is an unknown disease in the Mediterranean region. Dupuytren's contracture appears to be an extremity-related disease. Owing to the unclear etiology and a lack of up-to-date demographic data for northern Germany this study aims--together with the literature--to elucidate the role of associated illnesses in an attempt to discover pathogenic explanations. 566 patients suffering from Dupuytren's disease in the area around Hanover were analysed with respect to epidemiological features and their Tubiana contracture stage. 91.2% were of pure northern German stock, 12.5% had a family predisposition. The male-to-female ratio was 7:1. Men were afflicted on average at the age of 56 years. Intellectuals were scored 3.17, while manual workers scored 4.21. There were pre-existing ipsilateral lesions in 15% of cases. 55.1% had bilateral contracture. Ectopic penile and plantar fibrosis or knuckle pads were found in 6.7% of cases. The distribution of stages I-IV decreased by 2.4% from 59.1% among the 1,808 afflicted finger rays. With a score of 3.7-3.72, drinkers and smokers presented significantly more severe contractures, while the 8.2% of diabetics displayed a milder form. Among the epileptics--all of whom were affected bilaterally--the Tubiana stage of 3.71 exceeded the median manual score of 3.63 for the group as a whole. Thus Dupuytren's disease is a general but not an exclusively extremity-related sickness. The androtropy is pathognomic. Women develop the disease one decade later than men. In old age the male-to-female ratio equalizes. Drinkers, smokers and heavy manual workers present a more severe affliction, while diabetics suffer from a significantly less severe form. Although the ulnar type dominates, the radial type accounts for 14.4% of cases. 1.9 million Germans are chronically ill because of Dupuytren's disease. Despite a trauma history, Dupuytren's disease is not recognized as an occupational disease.

Adult↗
PubMed2001

Early soft tissue coverage after complex foot trauma.

Complex foot injuries require early and durable soft tissue coverage to reduce infection rates and fibrosis, thereby improving the functional outcome. Definitive wound closure with tissue transfer was achieved as an emergency procedure within 24 hours in 2 of 28 cases, as urgent revision within 72 hours in 9 of 28 cases, and as early revision within 120 hours in 15 of 28 patients. To evaluate the global foot function the Maryland Foot Score was applied to 17 of 28 patients at the 1-year follow-up. The mean score was 74.2 (of 100) points, indicating "good" to "sufficient" foot function. The outcome was superior compared with a series of 18 consecutive open calcaneus fractures with delayed soft tissue coverage (64.4 points). These results were confirmed with a modified Merle d'Aubigné Score. The overall infection rate could be lowered to 7.1% after complex foot injuries with early soft tissue coverage compared to 26 open calcaneus fractures (19.2%). Functional scores allow a reasonable overall assessment of the results, but they are centered on subjective criteria. Thus they must be viewed in conjunction with radiologic and biometric factors as well as criteria valuable for plastic reconstruction, such as two-point discrimination and durability. Unfortunately, emergency flap procedures are still rare in foot surgery, although they permit primary stable osteosynthesis even with complex foot trauma. The foot should gain the same functional rank as the hand with respect to acute or emergency flap procedures to avoid further complications.

Adolescent↗
PubMed2001

[Morphological and functional interface between palmar plates of metacarpophalangeal joints and intrinsic muscles of the hand].

UNLABELLED: Summary. After a ten-year period of intensively dealing with the hand as a Medical Artist, it became quite obvious that the palmar section of MP joints is described in the literature partly different from what we found in our cadaver studies. This especially applies to the proximal continuation and fixation of palmar plates and the deep transverse metacarpal ligament. Thus we tried to understand and explain the complex character of interaction between locomotion apparatus and structures of the hand's "connective-tissue body". METHOD AND MATERIAL: Cadaveric operation microscope-assisted dissection of the palmar ligament (plate), deep transverse metacarpal ligament, interosseous muscles as well as mechanically stable sections of the "connective tissue body" and fascia allowed a clear view of morphology, interaction, and character of these structures during passive finger motion. RESULTS: 1. Proximally, the palmar ligament (plate) of a metacarpophalangeal joint ranges to the tendinous sheets of origin of the interosseous muscles and in extension of these it is attached to the palmar carpal ligaments. In the following, these tendinous structures will be referred to as "deep longitudinal metacarpal fibres". This highly sophisticated proximal attachment is formed bilaterally from each palmar plate in several cascades. Thus, a widely ranging distribution of forces implied by MP-extension is guaranteed. The deep transverse metacarpal ligament executes the function of a "force dissipating center": Extension strain is passed on from the fingers via the "lateral digital sheet" and the "spiral ligament" to the palmar fascia and further on into a proximal and "deep" direction by the vertical sheets (Legueu and Juvara 1892/1974). On the next central level, a similar flow of forces reaches the palmar carpal ligaments from the osseous phalangeal base via the phalangoglenoidal ligaments and the palmar plate. Junction of these forces is the "soft tissue confluence" (Zancolli 1992), whereas the described "deep longitudinal metacarpal fibres" can be understood as a final common route. Overstretching forces at the index finger are transferred to the palmar carpal ligaments by a ligamentous "Arcus adductorius".2. Contrary to published reports, the palmar ligament (plate) does not have a determined and constant length but does adapt its extension in longitudinal direction to the joints' excursions, more than doubling in length in extended position compared to its minimal length in a maximally flexed MP joint. This is performed by criss-crossing fibers throughout the palmar ligament.3. Distally, the palmar ligament is attached to the base of the proximal phalanx on both sides with no mechanically relevant fixation in the middle. This predominant lateral attachment is additionally stabilized by the proximal section of the phalangoglenoidal ligaments, thus extending the area of osseous fixation. CONCLUSION: The biomechanical principle of restraining extension in the MP joints can be compared to the architecture of Gothic cathedrals or modern bridges. Here too, simple algorithms create complex systems. One major force (extension of MP joint) is split up into many single components to spread out the strain over a wide area. This allows high endurance with minimal expension of materials and simultaneously a well-distinguished mobility of the fingers. Operative treatment in this area (Zancolli's capsuloplasty for treatment of paralytic claw fingers) could be modified by considering these functional and morphological criteria, thus lowering frequency of relapse in palmar plate surgery.

Aged↗
PubMed2001

Reduction of systemic and cardiac adhesion molecule expression after off-pump versus conventional coronary artery bypass grafting.

Cardiopulmonary bypass (CPB) and operative trauma are associated with increased expression of proinflammatory mediators. We determined the relative contribution of CPB on activation of cytokines and adhesion molecules in patients undergoing coronary revascularization by comparing them with patients receiving off-pump coronary artery bypass grafting (OPCAB). Twenty-six patients were assigned to either the OPCAB procedure using a suction device and regular sternotomy (n = 13), or were treated conventionally using extracorporeal circulation, blood cardioplegia, and hypothermic arrest (29 degrees C-31 degrees C; n = 13). Systemic levels of TNF-alpha and the soluble adhesion molecules P-selectin and intracellular adhesion molecule 1 (ICAM-1) were assayed. Immunohistochemistry was used to account for cardiac-specific expression of adhesion molecules in interventricular endomyocardial sections. Both systemic and endomyocardial expression of adhesion molecules were lower in the OPCAB group. Coronary revascularization with CPB resulted in a significant higher expression of TNF-alpha, which was associated with P-selectin and ICAM-1 expression. This was accompanied with higher catecholamine requirement in the CPB group in the early postoperative period. Despite comparable surgical trauma, the OPCAB procedure without the use of CPB and cardioplegic arrest significantly reduces systemic and cardiac adhesion molecule expression and catecholamine requirement. Since the clinical course in the early postoperative period was comparable, larger trials are required to select the appropriate patient who benefits most from one or the other treatment regime.

Adult↗
PubMed2000

IG-therasorb immunoapheresis in orthotopic xenotransplantation of baboons with landrace pig hearts.

BACKGROUND: The major problem of xenotransplantation is, that hyperacute xenograft rejection (HXR) causes graft failure within minutes or a few hours because of natural antibodies and activation of the complement system. As a preclinical model we transplanted pig hearts orthotopically into baboons. To prevent HXR after orthotopic xenotransplantation (oXHTx), the immunoglobulins (Ig) and natural antibodies were adsorbed to reusable Ig-Therasorb immunoadsorption (IA) columns. METHODS: We performed three oXHTx of landrace pig hearts into baboons (19+/-6.8 kg), using extracorporeal circulation (ECC) connected to the IA unit. After separating the recipient's blood into plasma and cellular fraction by a plasma filter, plasma flow was directed to the Ig-Therasorb column coated with polyclonal sheep-antibodies against human IgG, IgM, and IgA. Intraoperative treatment consisted of 4 cycles of IA. For a control, we transplanted one pig heart into a baboon (16.9 kg) without applying IA. Perioperatively, serum concentrations of Ig, anti-pig-antibodies, complement and cardiac enzymes were determined. Tissue samples of myocardium were collected at the end of the study for immunohistochemical examinations, light microscopic examination (LM) and electron microscopic examination (EM). For cardiac monitoring after oXHTx, we used ECG, echocardiography, and invasive measurement of cardiac output. To prevent a mismatch of donor and recipient heart size, the donor pig had a 30-40% lower body weight than the recipient baboon. RESULTS: Four cycles of IA removed >80% of IgG, IgM, and IgA from plasma. The graft of the control animal failed after 29 min. The first oXHTx with IA was intentionally terminated after 100 min, the second oXHTx after 11 hr and the third oXHTx after 21 hr. All xenografts showed no histological signs of HXR. After weaning off ECC, these donor hearts worked in sinus rhythm without electrocardiographic ST-segment elevation. An excellent cardiac output was measured by echocardiography and thermodilution (2 L/min). Serological parameters indicating cardiac damage were significantly lower after IA if compared with the control experiment. Macroscopically, the xenograft of the control animal showed massive hemorrhage in comparison with the almost inconspicuous grafts after IA. The myocardium of the IA group demonstrated fewer deposits of Ig and complement components compared with the control animal. CONCLUSION: Baboons do not hyperacutely reject a porcine xenograft after antibody depletion by the Ig-Therasorb column. In our experiment only 4 cycles of immunoapheresis effectively prevented HXR after oXHTx of baboons. The Ig-Therasorb column is a reusable device, which can be handled easily in combination with the ECC. IA must be tested in oXHTx longterm survival experiments, especially in combination with transgenic pig organs, which could be a reliable preclinical approach for future clinical xenotransplantation.

Animals↗
PubMed2000

Influence of ischemic time on hyperacute xenograft rejection of pig hearts in a working heart perfusion model with human blood.

In xenotransplantation long ischemic time of grafts is supposed to have a marked influence on hyperacute rejection (HXR). We investigated the influence of different cold ischemic times on HXR of ex vivo "working pig hearts" perfused with human blood. Xenoreactive natural antibodies (XNAb) as a trigger of HXR were eliminated by Ig-Therasorb immunoadsorption (IA). Explanted Landrace pig hearts of group G1 and group G3 (with additional IA) underwent 4 h of cold ischemia prior to xenoperfusion. Control groups G2 and G4 (with IA) were kept ischemic for only 46.6 +/- 15.8 and 51.2 +/- 4.2 min, respectively. Ischemic time prolonged the perfusion time in our working heart model (G1: 356 +/- 46.1 min; G2: 125 +/- 31 min; P < 0.05). IA had no additional impact on perfusion time but was effective by itself. The heart weight increased fourfold more in G2 as compared to the other groups. IA without ischemia significantly improved cardiac output in G4 (G3: 198.8 +/- 15.4 mL/min; G4: 338.5 +/- 16.0 mL/min). Coronary flow in G2 was significantly lower than in G1 (G1: 157.9 +/- 9.15 mL/min; G2: 59.4 +/- 20.1 mL/min). Histological signs of HXR (light and electron microscopy) could be found in G2 in contrast to the other groups. Parameters of serological damage showed a minimum in G4 and the maximum in G2. In G1 XNAb were nearly equally eliminated immediately after the start of xenoperfusion as in IA groups G4 and G3. Four hours of ischemic time showed beneficial effects in preventing HXR, possibly caused by changes of the endothelial cell surface (for example, glycosylation or loss of alpha1-3Gal epitopes with a hapten effect).

Acute Disease↗
PubMed2000

Prevention of hyperacute xenograft rejection in orthotopic xenotransplantation of pig hearts into baboons using immunoadsorption of antibodies and complement factors.

To prevent hyperacute xenograft rejection (HXR) caused by preformed natural antibodies (XNAb) after orthotopic heart xenotransplantation (oXHTx) of landrace pig hearts into baboons, we used immunoadsorption of immunoglobulins IgG, IgM and IgA and complement with the reusable Ig-Therasorb column. In addition to functional data, tissue was sampled for histological, immunohistochemical and electron microscopical analysis. We performed three oXHTx of landrace pig hearts to baboons using extracorporeal circulation (ECC) connected to the immunoadsorption unit. Intraoperative treatment consisted of four cycles of immunoabsorption (IA). One oXHTx of a baboon without IA served as a control. A mismatch of donor and recipient heart size was prevented by selecting a 30-40% lower body weight of donor pigs than recipients. Four cycles of IA removed more than 80% of IgG, IgM and IgA, 86% of antipig antibodies and 66% of complement factors C3 and C4 from plasma. The graft of the control animal failed after 29 min. Orthotopic xenotransplantation with IA was selectively terminated after 100 min, 11 h and 21 h, respectively without any histological signs of HXR in light and electron microscopy. After weaning off from ECC these donor xenografts showed sufficient function with normal ECG and excellent cardiac output in echocardiography and invasive measurement (1.93 +/- 0.035 l/min). The myocardium of the control xenograft demonstrated more deposits of Ig and complement components (C3, C4) than in the IA group. Baboons survive HXR after orthotopic pig heart xenotransplantation due to antibody depletion by reusable Ig-Therasorb column treatment. Long-term survival in an orthotopic baboon xenotransplantation model after IA, especially in combination with transgenic pig organs, could be a reliable preclinical trial for future clinical xenotransplantation programs.

Acute Disease↗
PubMed2000

[Does tissue perfusion after free microvascular tissue transplantation remain autonomous?].

In a retrospective study, including 60 patients, after free latissimus dorsi transplantation (FLDT) to the lower leg, we found persistent pedicle blood flow up to ten years postoperatively. After uncomplicated FLDT, the pedicle supported the flap in all cases. After complicated FLDT (hematoma, thrombosis, infection) only 50% of all flaps after ten years were perfused by the vascular pedicle.

Adolescent↗
PubMed1999

Early experience with robotic technology for coronary artery surgery.

BACKGROUND: To achieve an endoscopic coronary bypass anastomoses we performed a study with endoscopic robotic instrumentation and camera guidance using three-dimensional (3-D) visualization. METHODS: The surgical robotic system ZEUS (Computer Motion Inc, Goleta, CA) consists of three interactive robotic arms and a control unit allowing the surgeon to move the instrument arms in a scaled down mode. The third arm (AESOP, Computer Motion Inc, Goleta, CA) positions the endoscope via voice control. The study had three phases. Phase I: In a phantom model, end-to-side anastomoses between vein grafts and the left anterior descending coronary artery (LAD) of 109 pig hearts were performed. Phase II: In 6 dogs (FBI, 20-25 kg) the left internal mammary artery (LIMA) was harvested endoscopically. During Port-Access (Heartport Inc, Redwood City, CA) cardiopulmonary bypass (CPB), LIMA and LAD were then anastomosed endoscopically with the help of telemetric ZEUS instruments (Computer Motion Inc). Phase III: A total of seven patients were operated on with help of the ZEUS system (Computer Motion Inc). After endoscopic LIMA harvesting and CPB using the Port-Access (Heartport Inc) system, the bypass graft (LIMA to LAD) was anastomosed endoscopically through three thoracic ports in 2 patients. Another 3 patients were operated on off-pump with regional stabilization and 2 patients with sternotomy and routine CPB. RESULTS: The practice with the phantom model and the subsequent animal experiments allowed the surgeons to gain sufficient experience for the clinical setting. In the clinical cases, times for anastomoses ranged from 20 to 42 minutes. Median internal mammary artery flow rate was 74 mL per minute (range 36-110 mL per minute). One patient in the off-pump group was converted to CPB and routine anastomosis. All patients had an uneventful angiographic control and postoperative course. CONCLUSIONS: Using telemetic technology, a completely endoscopic anastomosis of LIMA to LAD is possible on the arrested heart, as well as on the beating heart.

Anastomosis, Surgical↗
PubMed1999

Detection of coronary artery bypass graft patency by contrast enhanced magnetic resonance angiography.

OBJECTIVE: The subject and purpose of the prospective study was to delineate coronary artery bypass graft (CABG) course and to determine patency of aortocoronary venous bypass grafts (ACVB) compared with internal mammary artery bypass grafts (IMA) in the early postoperative follow-up, by contrast enhanced magnetic resonance angiography (MRA). For control, patients were examined with X-ray angiography and spiral-computed tomography (CT). METHODS: Eighty-five patients (74 male/11 female) with a mean age of 63.7 years underwent MRA examination, applying contrast enhanced gradient-echo sequence after an average distance of 7 days from CABG surgery. A 1.5 Tesla magnetom vision (Siemens, Erlangen, Germany) with phased array coil technology was used. Overall, 247 bypass grafts (160 ACVB/87 IMA) were studied with a 3D (three dimensional) ultrashort TE gradient-echo sequence (TR/TE/a:5 ms/2 ms/40 degrees) with 512*512 matrix and 500 mm FoV in single breath-hold technique after Gd-DTPA bolus injection. CABGs were judged in three different parts, including the course of CABG and both anastomoses. CABGs were controlled by angiography and spiral-CT to examine sensitivity, specificity and efficiency of MRA examination. Additional measurement of bypass graft flow velocity of arterial and venous grafts was performed with 2D phase contrast technique in breath-hold technique with ECG triggering. RESULTS: One hundred and thirty-nine of 160 (86.9%) ACVB grafts and 83 of 87 (95.4%) IMA grafts could be visualized. Suspected occlusions of 10 CABGs were confirmed in 80% with a second modality. Five CABGs were false positive in MRA. MRA proved a high specificity (93.8%), sensitivity (89.9%) and efficiency (1.73), especially in detection of IMA to LAD and ACVB to LAD and RCA (Table 1). 3D maximum intensity projection (MIP) reconstruction was helpful in delineating CABG course and in several cases in detecting stenosis of coronary arteries. Results of flow velocity showed a significant higher mean systolic velocity in arterial bypasses than in venous grafts with a higher maximum velocity in systole than in diastole in both grafts. Bypass stenosis in distal anastomosis could not be verified with MRA and flow method. CONCLUSION: Contrast enhanced 3D ultrashort TE gradient-echo magnetic resonance angiography has the potential for being a reliable method for CABG visualization and CABG patency determination in the early postoperative period. MR flow measurement was not qualified for detection of a bypass stenosis.

Aged↗
PubMed1999

The influence of antibody and complement removal with a Ig-Therasorb column in a xenogeneic working heart model.

OBJECTIVE: Organ transplantation is limited by the number of brain-dead human donors. Xenotransplantation could be an alternative to guarantee a constant supply of organs. A major problem of xenotransplantation are xenogeneic natural antibodies (XNAb) directed against species-specific antigens of a discordant donor species (e.g. pig). They trigger the hyperacute xenograft rejection (HXR). Re-usable immunoapheresis (LA)-columns Ig-Therasorb (Therasorb, Baxter) were used to adsorb these XNAb. The effect of immunoapheresis of the perfusing human blood was investigated in ex vivo working pig hearts. METHODS: Hearts of 12 landrace pigs (body weight 14-31 kg) were explanted after inducing cardiac arrest with 4 degrees C Celsior solution. Human blood (500 ml, heparinized) was obtained from healthy volunteers. In group 1 (G1, n = 6), blood as perfusate remained untreated. In group 2 (G2, n = 6), native blood was separated by plasmapheresis into cellular components and plasma. The latter passed through the Ig-Therasorb column for removal of immunoglobulins (so-called immunoadsorption or immunoapheresis). After back-table preparation the hearts were mounted to the working heart model. After 20 min of reperfusion in Langendorff mode, the working heart mode was established. Blood samples were taken isochronously for measurement of: CK(-MB), LDH, ASAT, troponin, immunoglobulins, complement activity, anti-pig antibodies and others. After cessation of the heart, atrial and ventricular tissue samples were taken for histological examinations (light/electron microscopy and immunohistochemistry). RESULTS: Two cycles of immunoapheresis reduced the levels of IgG by 84%, IgM by 83.3% and IgA by 76%. In G2, the antibody immunoadsorption of blood prolonged the duration of the working heart mode significantly to 335+/-37.5 min. In contrast, hearts of group 1 (control) failed after 125+/-31.3 min. Heart rate was significantly different between both groups (G1, 77.3+/-6.1 beats/min; G2, 86.5+/-5.5 beats/min). In G2 cardiac output was 118% and mean coronary flow was 154.6% higher than in G1. CK, LDH and ASAT showed no differences in the two groups. Heart weight increased significantly more in group 1 than in G2. Histological examination indicated specific signs of HXR in G1 after 1.5 h, whereas in G2 only slight unspecific damages were found after 6 h. CONCLUSION: Antibody removal by means of immunoapheresis results in a significantly improved xenogeneic cardiac function. Immunoapheresis may, therefore, become an important adjunct in future pig-to-man clinical xenotransplantation.

Animals↗
PubMed1999

Effects of prolonged cold storage time in xenotransplantation.

BACKGROUND: Ischemia and reperfusion injury after prolonged ischemic time (IT) has a marked influence on hyperacute xenograft rejection (HXR). The aim of the study was to investigate the impact of different cold ischemic times on the HXR of ex vivo "working pig hearts" perfused with human blood. Xenoreactive natural antibodies (XNAb) as the trigger of HXR were reduced by immunoadsorption (IA) using an Ig-Therasorb column. METHODS: Hearts of 24 Landrace pigs (13-31 kg) were harvested after cardioplegia with Celsior-solution and split into 4 groups. In Group C1 (n = 6) the short ischemic time (IT) lasted 48.9+/-10 minutes on the average prior to start of xenoperfusion, in Group I1 IT lasted 4 hours instead. Groups C2 and 12 experienced the same IT as C1 and I1, respectively, but underwent 2 cycles of IA in addition. IA removed immunoglobulins IgG, IgM and IgA from the perfusate. In the working heart mode hemodynamic parameters were measured in defined intervals. Blood samples were collected at the same time to determine myocardial enzymes, immunoglobulins, complement and anti-pig-antibodies. At the end of the study (cardiac arrest) tissue was sampled for histologic examination (light/electron microscopy (LM/EM) and immunohistochemistry). RESULTS: Survival time of the control Group C1 was 125 minutes. IA resulted in an extension of perfusion time to 6.5 hours in C2. Four hours of IT (I1) prolonged the working time of hearts when compared with C1. IA had no additional impact (I2). Heart weight increased significantly in C1 without IA. Cardiac output and coronary flow in C1 were significantly lower when compared with the other 3 groups. IA improved cardiac output (CO) in C2 (vs C1, p < 0.001). Histologic signs of HXR (LM/EM) could be found in C1 in contrast to the other groups. Serologic parameters for myocardial damage were higher in groups with prolonged IT than in groups with short IT. CONCLUSION: Prolonged ischemia and reperfusion injury showed controversial effects in this specific xenogeneic heart transplant model. In contrast to observations in allogeneic transplantation 4 hours of IT showed a beneficial behaviour of the xenografts. Reasons could be either a protective effect of the Celsior solution or changes of the endothelial cell surface (in terms of glycosylation or loss of alpha1-3Gal-epitopes). Tolerance of prolonged IT would allow transportation of xenografts over long distances.

Animals↗