Biomedical subjects

T Schaffner

Publications and source records attributed to T Schaffner.

At least 19 recordsLinked to original sources

PubMed2006

[Pulmonary microscopic tumor embolism syndrome].

HISTORY: A 76-year-old woman and a 62-year-old man were both referred to our clinic because of an unexplained weight loss, increasing dry cough and shortness of breath. INVESTIGATIONS: Investigations revealed an adenocarcinoma of the colon with retroperitoneal, mediastinal and supraclavicular lymph node metastasis and poorly differentiated carcinoma of the prostate with extensive bone metastases. During their hospital stay both patients developed increasing shortness of breath and clinical signs of right heart failure. Echocardiography confirmed severe pulmonary hypertension and dilatation of the right ventricle in both patients. Despite the high degree of clinical suspicion CT scans of the thorax could not demonstrate pulmonary embolism. DIAGNOSIS, TREATMENT AND COURSE: During the following days the patients condition deteriorated further and both patients' died from irreversible right heart failure. Both autopsies showed extensive metastatic adenocarcinoma with marked angiosis carcinomatosa of the lungs with numerous occlusions of small arteries and arterioles and resulting cor pulmonale. Thrombotic pulmonary embolism could not be detected. CONCLUSION: In patients with malignant neoplasms, especially adenocarcinomas, dyspnea and signs of increasing pulmonary artery pressure, the possibility of a microscopic pulmonary tumor embolism should be considered after exclusion of more usual causes especially thrombotic pulmonary embolism. In selected cases a cytologic examination of blood aspirated from a wedged pulmonary artery catheter can be performed to prove angiosis is carcinomatosa.

Adenocarcinoma↗

PubMed2005

PPS-PEG surface coating to reduce thrombogenicity of small diameter ePTFE vascular grafts.

AIMS: Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). METHODS: In five domestic pigs (25-30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS)--poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semi-quantitative assessment (score 0-3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0-3) histologic evaluation of tissue reaction. RESULTS: In the pig model, cellular deposition and microthrombi formation increased over time. In non- heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts,especially in PPS -PEG dry (p<0.05), and highest in controls. Cell deposition was lowest in PPS-PEG dry, but this difference was not statistically significant vs.controls. In the rat model,no significant differences of the tissue reaction could be shown between materials. CONCLUSION: While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS -PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus appears to be promising for improving graft patency of small synthetic vascular prostheses.

Animals↗

PubMed2001

Successful management of a B-type cardiac allograft into an O-type man with 3(1/2)-year clinical follow-up.

BACKGROUND: In May 1997, a 19-year-old male patient of histo-blood group type O suffering from congenital end-stage heart failure accidentally received a cardiac allograft of type B and is still alive in fair condition. METHODS: In addition to conventional immunosuppressive therapy, plasma exchange (PEX), extracorporeal immunoabsorption (EIA), intravenous immunoglobulins (IVIG), and C1 inhibitor were used. RESULTS: Such treatment successfully reduced both IgM and IgG anti-B levels and complement hyperactivity and allowed to reach the state of accommodation without obvious signs of rejection. The patient has been surviving for 42 months; retransplantation with an O-type heart remained unnecessary. CONCLUSION: Humoral rejection has been avoided in this patient, with PEX, EIA, IVIG, and C1 inhibitor substantially contributing to this success. With future availability of such combined therapies, preferably before transplantation, vascular rejection events caused by preformed antibodies and complement (ABO mismatch or anti-HLA) could be prevented or treated.

ABO Blood-Group System↗

PubMed2001

Polylactide implants and bacterial contamination: an animal study.

Although bioresorbable aliphatic polyesters derived from lactic acid are now used clinically as sutures, bone-fracture fixation devices and sustained-release drug-delivery systems, very little is known about their behavior in the infected environment. The aim of the present study was to compare the resistance to infection of two polylactide implants with different degradation characteristics, and to evaluate the influence of a bacterial challenge on their mechanical and physicochemical properties. Various quantities of a beta-haemolyzing strain of Staphylococus aureus (V 8189-94) were inoculated into the medullary cavity of rabbit tibiae, and an extruded polylactide rod composed of either P(L)LA (Poly(L-Lactide)) or P(L/DL)LA (Poly(L/DL-Lactide)) was then inserted. Animals were sacrificed four weeks after surgery. The tibiae and implants were removed under sterile conditions and evaluated microbiologically by culturing. The severity of infection was graded according to positive colony-forming units in the bone. The mechanical properties of the retrieved implants were assessed by 4-point bending and shear tests, performed in compliance with the ASTM D790 standard and their physicochemical characteristics also were characterized. P(L)LA and P(L/DL)LA implants were equally resistant to local infection, their mechanical and physicochemical properties being unaffected by bacterial challenge. Hence, once an infection has become established, the release of bactericidal/bacteriostatic by-products during implant degradation does not appear to affect its natural course. The release of bactericidal/bacteriostatic degradation products at the implantation site is unlikely to affect the natural course of an established infection.

Animals↗

PubMed2001

Laser solder welding of articular cartilage: tensile strength and chondrocyte viability.

BACKGROUND AND OBJECTIVE: The surgical treatment of full-thickness cartilage defects in the knee joint remains a therapeutic challenge. Recently, new techniques for articular cartilage transplantation, such as mosaicplasty, have become available for cartilage repair. The long-term success of these techniques, however, depends not only on the chondrocyte viability but also on a lateral integration of the implant. The goal of this study was to evaluate the feasibility of cartilage welding by using albumin solder that was dye-enhanced to allow coagulation with 808-nm laser diode irradiation. STUDY DESIGN/MATERIALS AND METHODS: Conventional histology of light microscopy was compared with a viability staining to precisely determine the extent of thermal damage after laser welding. Indocyanine green (ICG) enhanced albumin solder (25% albumin, 0.5% HA, 0.1% ICG) was used for articular cartilage welding. For coagulation, the solder was irradiated through the cartilage implant by 808-nm laser light and the tensile strength of the weld was measured. RESULTS: Viability staining revealed a thermal damage of typically 500 m in depth at an irradiance of approximately 10 W/cm(2) for 8 seconds, whereas conventional histologies showed only half of the extent found by the viability test. Heat-bath investigations revealed a threshold temperature of minimum 54 degrees C for thermal damage of chondrocytes. Efficient cartilage bonding was obtained by using bovine albumin solder as adhesive. Maximum tensile strength of more than 10 N/cm(2) was achieved. CONCLUSIONS: Viability tests revealed that the thermal damage is much greater (up to twice) than expected after light microscopic characterization. This study shows the feasibility to strongly laser weld cartilage on cartilage by use of a dye-enhanced albumin solder. Possibilities to reduce the range of damage are suggested.

Animals↗

PubMed2001

Comparative in vitro study of tissue welding using a 808 nm diode laser and a Ho:YAG laser.

In vitro porcine arteries and veins have been welded end-to-end using either a 808 nm diode laser combined with an indocyanine green enhanced albumin solder, or with a continuous-wave (cw) Ho:YAG laser without biological solder. The vascular stumps were approached to each other over a coronary dilatation catheter in order to obtain a precise alignment and good coaptation. Standard histology revealed for both welding techniques lateral tissue damage between 2 and 3 mm caused by laser-induced heat. Good solder attachment to the tissue was observed by the use of a scanning electron microscope. The vessels soldered with the 808 nm diode laser using albumin solder showed considerably higher tensile strength (1 N compared to 0.3 N) than vessels welded exclusively by Ho:YAG laser radiation. In contrast, leaking pressure (350 +/- 200 mmHg) and bursting pressure (457 +/- 200 mmHg) were found to be independent of the welding technique used. This study demonstrates that fast (total welding time about 2-5 min), stable and tight microvascular anastomosis can be achieved with the use of a dye-enhanced albumin laser soldering technique and an ancillary coronary dilatation catheter.

Anastomosis, Surgical↗

PubMed2001

Prevention of neointimal proliferation by immunosuppression in synthetic vascular grafts.

OBJECTIVE: Immunosuppressive agents have been proposed to reduce neointimal hyperplasia in synthetic vascular grafts. Thus, the purpose of the present study was to evaluate the safety and efficacy of rapamycins (systemic vs. local vs. oral administration) and mycophenolate mofetil (MMF) to reduce intimal hyperplasia in infrarenal synthetic vascular grafts of the rat. METHODS: Fifty-four Wistar rats (250 g) completed the study after a synthetic vascular graft (ePTFE, Gore-tex, 2 mm diameter, 10 mm length) was implanted end-to-end in the infrarenal aorta. The animals were divided into three groups: group 1 consisted of 12 control animals, group 2 consisted of 37 rats receiving rapamycins, either per os (RAD, 1.5 or 3 mg/kg), intraperitoneally (RPM, 1.5 or 3 mg/kg) or locally (RPM soaking of the graft); and in group 3 (n=5), MMF (40 mg/kg) was administered orally. The animals were followed weekly with weight controls and signs of toxicity for 30 (n=37) and 60 (n=17) days, respectively. All animals were sacrificed and underwent histological examination at completion of the study. RESULTS: All animals survived in groups 1 and 3, but five died in group 2. The weight gain was normal in all groups, except for the subgroup 2a receiving high dose rapamycins orally. All rats in group 3 suffered from diarrhea, whereas animals receiving high dose rapamycins showed toxic signs (hair loss, wound healing problems). Histological examination showed a significant increase in intimal hyperplasia in group 1 (0.03+/-0.01 and 0.14+/-0.05 microm after 30 and 60 days, respectively; P<0.01). Rapamycins in either application or dosage had no significant effect on intimal hyperplasia. CONCLUSIONS: Local or systemic administration of rapamycins has no effect on intimal hyperplasia in synthetic vascular grafts. In contrast, toxic signs with weight loss were observed in animals treated with high dose rapamycins, but not in those treated with MMF. Thus, in the rat model, immunosuppression with rapamycins or MMF cannot be recommended for the prevention of intimal hyperplasia in the synthetic vascular graft model.

Anastomosis, Surgical↗

PubMed2001

Low molecular weight dextran sulfate prevents complement activation and delays hyperacute rejection in pig-to-human xenotransplantation models.

Dextran sulfate of 5000 molecular weight (DXS 5000) is known to block complement activation as well as the intrinsic coagulation cascade by potentiation of C inhibitor. The effect of DXS 5000 on hyperacute rejection (HAR) was tested in pig-to-human xenotransplantation models. For in vitro testing, a cytotoxicity assay was used with the pig kidney cell line PK15 as target cells and fresh, undiluted human serum as antibody and complement source. Ex vivo pig lung perfusion was chosen to assess DXS 5000 in a physiologic model. Pig lungs were perfused with fresh, citrate-anticoagulated whole human blood to which 1 or 2 mg/ml DXS 5000 were added; the lungs were ventilated and the blood de-oxygenated. Pulmonary vascular resistance (PVR) and blood oxygenation (deltapO2) were monitored throughout the experiment. Autologous pig blood and human blood without DXS 5000 served as controls. In the PK 15 assay DXS 5000 led to a complete, dose-dependent inhibition of human serum cytotoxicity with an average IC50 of 43 +/- 18 microg/ml (n=8). Pig lungs perfused with untreated human blood (n=2) underwent HAR within 105 +/- 64 min, characterized by increased PVR, decrease of deltapO2, and generalized edema. Microscopically, capillary bleeding as well as deposition of human antibodies, complement and fibrin could be observed. Addition of DXS 5000 (n=4) prolonged lung survival to 170 +/- 14 min for 1 mg/ml and 250 +/- 42 min for 2 mg/ml. and PVR values as well as edema formation were comparable to control lungs that were perfused with autologous pig blood (n=2). Activation of complement (activation products in serum, deposition on lung tissue) and the coagulation system (fibrin monomers) were significantly diminished as compared to human blood without DXS 5000. Binding of anti-Gal antibodies was not influenced, and in vitro experiments showed no evidence of complement depletion by DXS 5000. In conclusion, DXS 5000 is an efficient complement inhibitor in pig-to-human xenotransplantation models and therefore a candidate for complement-inhibitory/anti-inflammatory therapy either alone or in combination with other substances and warrants further investigation.

Animals↗

PubMed2001

Prevention of venous graft sclerosis with clopidogrel and aspirin combined with a mesh tubing in a dog model of arteriovenous bypass grafting.

OBJECTIVE: to investigate the effect of clopidogrel combined with aspirin or aspirin alone on fibromyointimal hyperplasia (FIMH) in a bypass model with native vein grafts (NVG) and biocompound grafts (BCG). DESIGN: twelve Beagle dogs were randomised into two equal groups. In each animal NVG and a BCG were interposed in the common carotid arteries. Postoperatively, Group 1 received clopidogrel (200 mg/d) and aspirin (100 mg/d) and Group 2 received aspirin (100 mg/d) alone. METHODS: the BCG was constructed by sheathing the ipsilateral jugular vein with highly flexible metal mesh tubing. After 30 days the grafts were harvested and pressure fixed. FIMH was determined by morphometry. RESULTS: the average wall thickness of the BCG was significantly lower than that of the NVG in both groups (0.26 (SD)0.02 mm vs 0.47 (SD)0.15 mm, p = 0.04 and 0.28 (SD)0.05 mm vs 0.70 (SD)0.29 mm, p = 0.01, respectively). For BCG treated with aspirin, the wall cross section area was lower (5.0 (SD)0.6 mm(2)vs 9.1 (SD)3.3 mm(2), p = 0.02) and the lumen larger (25.2 (SD)5.9 mm(2)vs 9.7 (SD)3.4 mm(2), p < 0.01) than for the NVG. There was also a difference in the lumen cross section area of the NVG, which was larger after combined therapy with clopidogrel and aspirin (17.9 (SD)7.8 mm(2)vs 9.7 (SD)3.4 mm(2), p = 0.04). CONCLUSIONS: in this dog model the sheathing of vein grafts effectively prevents FIMH following bypass surgery. Clopidogrel is effective in NVG.

Animals↗

PubMed2001

Quantification of laser-induced cartilage injury by confocal microscopy in an ex vivo model.

BACKGROUND: The application of lasers in orthopaedic surgery is increasing. However, some investigators have reported that osteonecrosis may occur after laser meniscectomy. The objective of the present study was to evaluate the effect of laser wavelength and energy on cartilage injury in an ex vivo model. METHODS: Fresh bovine articular cartilage was exposed to either holmium:yttrium-aluminum-garnet (Ho:YAG) or erbium:YAG-laser (Er:YAG) irradiation. Both lasers were operated in a free-running mode and at a pulse-repetition rate of 8 Hz. The effect of laser treatment at several energy levels (Er:YAG at 100 and 150 mJ and Ho:YAG at 500 and 800 mJ) was examined. For each light source and energy level, ten cartilage samples were assessed by conventional histological analysis and by confocal microscopy. Thermal damage was assessed by determining cell viability. RESULTS: The extent of thermal damage demonstrated by confocal microscopy was much greater than that demonstrated by histological analysis. The extent of thermal injury after Ho:YAG-laser irradiation was much greater than that after Er:YAG-laser irradiation, which was associated with almost no damage. In addition, the ablation depth was greater after treatment with the Er:YAG laser than after treatment with the Ho:YAG laser. CONCLUSIONS: In the present study, histological analysis underestimated thermal damage after laser irradiation. In addition, our findings highlighted problems associated with use of high-power settings of Ho:YAG lasers during arthroscopic surgery.

Animals↗

PubMed2000

Acute and chronic effects of transmyocardial laser revascularization in the nonischemic pig myocardium by using three laser systems.

BACKGROUND AND OBJECTIVE: Transmyocardial laser revascularization (TMLR) improves symptoms in patients with coronary heart disease. It is based on the hypothesis of direct perfusion of ischemic myocardium by means of laser-created channels. Three different lasers were used to study alternative effects on myocardium. STUDY DESIGN/MATERIALS AND METHODS: The present study was conducted to evaluate comprehensively and compare the short and long-term tissue effects and the basic interaction mechanisms of CO2, Ho:YAG, and Er:YAG laser radiation with myocardium. The dynamics of laser-induced impacts in gel used as tissue phantom was visualized by time-resolved flash photography. Pressure measurements performed during perforation of myocardium in vitro revealed the explosive character of the ablation process. Channels made into the left ventricle of normal pig hearts were examined immediately and 6 weeks after creation. RESULTS: Regardless of laser source, all channels became occluded within 6 weeks by scar. Minimal acute thermal damage by Er:YAG laser corresponded to smaller scars. Pulsed Ho:YAG caused stronger tissue tearing than continuous wave CO2 irradiation. An increased volume density of intramyocardial vessels was found about the scars 6 weeks after treatment with all lasers. CONCLUSION: The laser sources permitted to study outcome of pressure effects and thermal damage in vivo. There were only minor differences between the three laser systems used. Rapid channel occlusion suggests that rather than revascularization, subsidiary physiologic tissue effects elicited by the thermal, oxidative, or mechanical action of the laser impact may contribute to the beneficial clinical effects of TMLR.

Animals↗

PubMed2000

Differential expression of chemokines in normal pancreas and in chronic pancreatitis.

BACKGROUND & AIMS: Cellular infiltrates are present already in early stages of chronic pancreatitis. The mechanisms responsible for their recruitment are unknown. Hence, we determined the differential expression of chemokine genes and their cellular sources in normal and affected pancreatic tissues. METHODS: Pancreatic tissues from 23 patients with chronic pancreatitis and from 4 normal controls were subjected to in situ hybridization for detecting messenger RNA (mRNA) of the chemokine genes interleukin 8, ENA-78, MIG, MCP-1, and I-309. RESULTS: Normal pancreatic tissues lack cells expressing mRNA for IL-8, ENA-78, MIG, and MCP-1. In contrast, pancreatic lobuli with mild to moderate signs of tissue alterations strongly expressed MCP-1 mRNA in centroacinar ducts, endothelia, fibroblasts, macrophages, T cells, and occasionally in nerves. Interleukin 8 and ENA-78 mRNA is preferentially detected in centroacinar ducts of pancreatic lobuli with more advanced alterations. Variable numbers of pancreas-infiltrating T cells express MIG mRNA. I-309 mRNA, however, is consistently observed in normal acini and in tissue with mild to moderate signs of tissue alterations. CONCLUSIONS: The observed differential expression of distinct chemokine genes in pancreatic parenchyma and infiltrates from patients with chronic pancreatitis strongly suggests an involvement of distinct chemokines in the initiation and perpetuation of disease.

Adult↗

PubMed2000

Effect of azithromycin plus rifampin versus amoxicillin alone on eradication and inflammation in the chronic course of Chlamydia pneumoniae pneumonitis in mice.

The effects of treatment with azithromycin plus rifampin (A+R), amoxicillin (A), or placebo (P) on the chronic course of experimental Chlamydia pneumoniae pneumonitis in mice were assessed by culture, PCR, and immunocytochemistry as well as by degree of inflammation in lung tissue. Eradication of the pathogen was significantly more frequent and inflammation in tissue was significantly reduced after treatment with A+R compared to after treatment with A or P. Combination therapy with azithromycin plus rifampin showed favorable effects in the chronic course of C. pneumoniae pneumonitis.

Amoxicillin↗

PubMed1999

Diastolic dysfunction and collagen structure in canine pacing-induced heart failure.

Heart failure is characterized not only by systolic, but also by diastolic dysfunction. The present study tested whether or not diastolic dysfunction is associated with changes in tissue properties and collagen network structure. Heart failure was induced in seven chronically instrumented, conscious dogs by rapid left ventricular pacing (2 50 min(-1)). After 2-5 [mean: 4+/-1 (S.D.)] weeks pacing, heart failure was apparent from clinical symptoms (ascites, cachexia, edema, exercise intolerance) and hemodynamic parameters (significant increases of heart rate and left ventricular end-diastolic pressure and decreases of left ventricular maximal pressure, dP/dtmax and systolic wall thickening). The left ventricle was dilated, as indicated by a decrease of end-diastolic wall thickness (6.3+/-2.0 v 7.2+/-2.1 mm; P<0.05; sonomicrometry). The left ventricular end-diastolic pressure-strain relation (strain: relative change of end-diastolic wall thickness) was obtained during alterations of loading conditions by inferior caval vein and descending thoracic aortic occlusion. The slope of this relation increased from 85+/-20 to 428+/-188 in heart failure, indicating an increase of left ventricular stiffness. Collagen was stained with picrosirius red and analyzed using polarized light microscopy. In heart failure, the collagen volume fraction remained unchanged (1.9+/-1.2 v 2.3+/-1.3%; N.S.), while the nonuniformity of collagen orientation, as reflected by its standard deviation, was increased (11.1+/-1.8 v 6.1+/-0.4 o; P<0.05). The nonuniformity of collagen fiber orientation correlated with left ventricular stiffness [r=0.75].

Animals↗

PubMed1999

Cortical regions contributing to the anterior commissure in man.

The human anterior commissure is believed, by extrapolation from data obtained in macaque monkeys, to convey axons from the temporal and orbitofrontal cortex. Reports of interhemispheric transfer and sexual dimorphism related to the anterior commissure, however, make more precise data on the human anterior commissure desirable. We investigated the connectivity of the human anterior commissure in six adults (male and female) that had circumscribed hemispheric lesions in temporal, frontal, parietal or occipital cortices or in infrapallidal white matter using the Nauta for anterogradely degenerating axons. Axons originating in the inferior part of temporal or occipital lobes, occipital convexity and possibly central fissure and prefrontal convexity were found to cross the midsagittal plane in the anterior commissure. The largest contingent of commissural axons originated in the inferior part of the temporal lobe; it displayed a roughly topographic organization, preferentially running through the inferior part of the commissure. The inferior temporal contingent seemed to reach homotopic and heterotopic targets in the opposite hemisphere. Among the latter were the amygdala and possibly the orbitofrontal cortex. The present data suggest that the human anterior commissure conveys axons from much larger territories than expected from work on non-human primates. Similarly to the human and non-human primate corpus callosum, the anterior commissure is roughly topographically organized and participates in heterotopic connectivity.

Aged↗

PubMed1998

Improvement of patency rate in heparin-coated small synthetic vascular grafts.

BACKGROUND: Graft thrombosis and intimal hyperplasia represent the major causes of graft failure. Heparin has been shown to have a beneficial effect on long-term patency and on prevention of intimal hyperplasia. Thus, the purpose of the present study was to evaluate the effect of heparin coating on patency rate and intimal hyperplasia in small synthetic vascular grafts. METHODS AND RESULTS: Two synthetic grafts (expanded polytetrafluoroethylene [ePTFE], and polyurethane) with and without heparin coating were implanted in the infrarenal aorta (diameter, 2 mm) of 40 Whistar rats. Animals survived 8 weeks after implantation. Graft patency, intimal thickness, and percentage of diameter stenosis were determined by light microscopy at the proximal respectively distal anastomosis and in the middle of the graft. Uncoated grafts showed a patency rate of 70% for ePTFE and 60% for polyurethane grafts. Heparin-coated grafts showed a patency rate of 100% for ePTFE and 90% for polyurethane grafts. Intimal hyperplasia was observed in all grafts mainly at the anastomosis site. Intimal wall thickness and percentage of stenosis were significantly more pronounced in the polyurethane than ePTFE grafts (P < 0.01). Heparin coating significantly reduced overall graft thrombosis (P < 0.05) but had no significant effect on intimal hyperplasia. CONCLUSIONS: Small grafts show a high rate of graft thrombosis and an enhanced intimal hyperplasia. ePTFE grafts show significantly less intimal hyperplasia and percentage of stenosis than polyurethane grafts. Heparin coating significantly reduced graft thrombosis but had no significant effect on intimal hyperplasia. Thus, heparin coating seems to be beneficial for graft patency, and ePTFE appears to be superior to polyurethane as graft material.

Animals↗

PubMed1998

Assessment of troponin-T for detection of clinical cardiac rejection.

Non-invasive detection of cardiac rejection still remains a challenge after heart transplantation. We assessed troponin-T as a new serum marker to diagnose cardiac rejection. Twenty-five heart transplant patients (Berne) were monitored prospectively for up to 2 years, and compared to 89 retrospectively assessed patients (Stanford). Blood samples (392 Berne and 320 Stanford) were analyzed (creatine kinase, isoenzymes MB activity and MB mass, troponin-T and troponin-I). Regression analysis between the results of these blood samples and cardiac rejection grading from simultaneously performed endomyocardial biopsies was carried out. Troponin-T tests done in two different laboratories showed a good correlation (r = 0.91; P < 0.0001), whereas troponin-T versus troponin-I showed a lower correlation (r = 0.53; P < 0.0001). Troponin-T and -I in contrast to other enzymes were elevated for a longer period (up to 4 weeks before returning to baseline) after transplantation than during conventional cardiac surgery. Beyond 3 months the following correlations were found between troponin-T (new or old test) and the other enzymes (creatine kinase: r = 0.26, MB activity: r = 0.4, and MB mass: r = 0.68). The correlation between the degree of rejection and the enzyme release is poor, however, the best results were obtained for troponin-T (r = 0.22; P < 0.001). We found a low correlation between troponin-T and the degree of rejection beyond 3 months after heart transplantation. Despite a troponin-T elevation in some patients with rejection, the new test is not sensitive enough to be used alone for the non-invasive diagnosis of cardiac rejection.

Biomarkers↗

PubMed1998

Assessment of cardiac rejection by MR-imaging and MR-spectroscopy.

BACKGROUND: Detection of cardiac rejection is a major problem in cardiac transplantation. The gold standard is, and remains, endomyocardial biopsy. PURPOSE: Evaluation of MR-imaging and MR-spectroscopy for detection of cardiac rejection. METHODS: Orthotopic cardiac transplantation (HTX) was performed in 13 pigs (body weight 30 kg). All animals obtained immunosuppressive (triple) therapy for 1 week after the operation. Thereafter immunosuppression was stopped to induce cardiac rejection. MRI and MRS (1.5 Tesla General Electrics Signa) were performed pre- and post-operatively on days 10, 17, 24 and 31. The degree of rejection was determined post-operatively using endomyocardial biopsy (Texas grading score). RESULTS: (1) MR-imaging: LV function remained unchanged after HTX. LV mass increased (+42%; P < 0.05) with cardiac rejection. (2) MR-spectroscopy: a marked reduction in the ratio of phosphocreatine and adenosine triphosphate, respectively, to inorganic phosphate was observed in the rejecting hearts. (3) Histologic grading confirmed cardiac rejection after stopping immunosuppression. The Texas score was 5.7+/-0.8 at autopsy. CONCLUSIONS: MR-imaging and MR-spectroscopy allow the detection of changes associated with cardiac rejection. Both techniques are correlated with histologic rejection. However, endomyocardial biopsy remains the gold standard for reliable detection of cardiac rejection.

Adenosine Triphosphate↗