[Chronic pain after thoracotomy].
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Chronic Disease↗
Biomedical subjects
B Reichart
Publications and source records attributed to B Reichart.
Oxidative metabolism of the transplanted human heart assessed by positron emission tomography using C-11 acetate.
For investigation of the metabolic profile of the transplanted human heart, positron emission tomography with C-11 acetate was performed to compare global and regional oxidative metabolism in 14 transplant patients with that in 10 healthy volunteers. Because no difference between transplants and normals could be observed, the results suggest that oxidative metabolism remains stable after transplantation, whereas cardiac work remains the major determinant.
Carbon Radioisotopes↗
Serial assessment of sympathetic reinnervation after orthotopic heart transplantation. A longitudinal study using PET and C-11 hydroxyephedrine.
BACKGROUND: Little is known about the progressiveness of sympathetic reinnervation late after cardiac transplantation (HTX). The aim of the present study was to describe individual growth of sympathetic terminals after HTX by a longitudinal quantitative assessment. METHODS AND RESULTS: In 20 patients after HTX, dynamic PET with C-11 hydroxyephedrine (HED) was performed twice within 3.0+/-0.5 years. According to the time interval between HTX and first PET, subgroups of patients early (group A, <1.5 years; n=7), intermediate (group B, 1.5 to 7 years; n=7) and late (group C, >7 years; n=6) after HTX were defined. At the time of first HED PET, 10 patients were completely denervated (7 in group A, 2 in group B, and 1 in group C). Only 3 remained denervated at second PET. A significant increase of reinnervated myocardium between first and second PET was found in all 3 groups (0% to 9+/-9% of left ventricle for group A, P<0.05; 13+/-12% to 23+/-17% for group B, P<0.05; 21+/-21% to 37+/-23% for group C, P<0.05). The magnitude of increase was similar between groups. Reinnervation was first surveyed in the basal anterior region, then toward apex, septal, and lateral wall. Inferior wall remained denervated. The largest reinnervated area surveyed in an individuum was 66% of the left ventricle. CONCLUSIONS: The present data confirm the low likelihood of sympathetic reinnervation within 18 months after HTX. Once the reinnervation process is initiated, a continuous growth is observed even late after HTX, suggesting a progressive nature of reinnervation. Reinnervation, however, remained regionally heterogeneous, and a complete restoration was not found until 15 years after HTX.
Adult↗
[Homografts for mitral valve replacement in florid endocarditis--an alternative to prosthetic replacement].
INTRODUCTION: Homografts for valve replacement are indicated in acute valve endocarditis. It is assumed that they possess anti-infective properties. Homografts are an established indication in aortic valve replacement. We present our early results with homografts for mitral valve replacement in acute endocarditis. PATIENTS AND METHODS: Between July 1996 and March 1998 we used cryopreserved homografts for mitral valve replacement in seven patients. In three cases (age 24, 42, and 34 years) the indication was an acute endocarditis with subsequent severe mitral valve insufficiency. The size of the required homograft was measured preoperatively using transesophageal echocardiography. For implantation the technique described by A. Carpentier was used; for stabilization of the mitral anulus a valvular ring (Physio) was implanted. Follow-up was done every six months including clinical and echocardiographical examinations. After the first postoperative year an Ultrafast-CT was done in addition. RESULTS: One patient had complete mitral valve replacement, in the other two cases the diseased parts of the valve were completely excised and the valve was repaired using a partial homograft. There were no perioperative deaths. In the follow-ups, up to 24 months of uneventful homograft function was documented by echocardiography; no insufficiency > degree I was seen on color Doppler echocardiography. At the last follow-up (mean follow-up 16 months, range 12 to 24 months) the average mitral valve orifice was 2.5 +/- 0.5 cm2, the mean pressure gradient 2.8 +/- 0.8 mm Hg. In Ultrafast-CT no morphological abnormalities of the mitral valves and no dilatation of the left ventricle were seen. There were no signs of a recurrence of the endocarditis in any patient during the follow-up period. CONCLUSION: Homografts for mitral valve replacement are an interesting alternative to prosthetic valve replacement, especially in younger patients. In cases with acute endocarditis, in which mechanical prosthesis should not be used, a reconstruction or repair of the mitral valve with preservation of the ventricular geometry is possible even if large parts of the mitral valve are infected.
Adult↗
Mitral commissurotomy, a technique outdated? Long-term follow-up over a period of 35 years.
BACKGROUND: The objective of this study was to evaluate long-term survival, valve-related complications as well as prognostic factors for early and late outcome after open and closed mitral commissurotomy covering a follow-up period of 35 years. METHODS: From 1955 to 1977, 183 patients with mitral stenosis underwent mitral commissurotomy at our institution. Closed valvotomy was performed on 143 patients (group A) and open valvotomy on 40 patients (group B). RESULTS: Survival rates after 10, 20, and 30 years were 89%, 67.8%, and 49.1% in group A and 91.7%, 66.7%, and 45.9% in group B (p = not significant). The risk of late death increased significantly with an advanced preoperative New York Heart Association functional class, atrial fibrillation, higher age at operation, pre- or postoperative mitral regurgitation, and leaflet calcification. Forty-four patients in group A and 5 patients in group B required reoperation (p < 0.05). Independent predictors for reoperation in a multivariate analysis were a remaining postoperative mitral stenosis or regurgitation. A total of 68 patients showed valve-related complications. The linearized rate of valve-related morbidity and mortality was 2.1% per patient-years in group A versus 1.1% per patient-years in B (p < 0.01). CONCLUSIONS: Long-term survival for open and closed commissurotomy are excellent, showing no difference between the groups. However, both the incidence of reoperation as well as valve-related morbidity and mortality were significantly lower after open commissurotomy. In well-selected patients with pure mitral stenosis and no leaflet calcification, open commissurotomy still remains a valid surgical option.
Adult↗
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↗
Less invasive, continuous hemodynamic monitoring during minimally invasive coronary surgery.
BACKGROUND: Minimally invasive coronary surgery has gained more and more clinical acceptance. A clear contrast to the minimally invasive idea is the highly invasive pulmonary artery catheter used for hemodynamic monitoring during the operation. We evaluated a less invasive device which calculates cardiac output (CO) and hemodynamics based on arterial pulse-contour analysis. METHODS: In 20 patients revascularized by the off-pump technique with the octopus system, agreement of CO by pulse-contour was compared to pulmonary arterial and femoral arterial thermodilution and hemodynamic alterations during the operation were recorded. Pulse-contour CO is computed by measuring the area under the arterial pressure waveform and dividing it by aortic impedance. Aortic impedance is determined by an arterial thermodilution at the onset of the system. RESULTS: Correlation of pulmonary arterial and arterial thermodilution CO to pulse-contour CO was 0.91 and 0.90 respectively (both p<0.01). Coefficients of variations were 6.2% and 6.7%. The bias was 0.1 L per minute and standard deviations were 0.42 L per minute and 0.55 L per minute. Hemodynamic changes during the operations were seen mainly during the distal anastomosis of the first diagonal branch; only slight changes occurred during the anastomosis of the left anterior descending coronary artery. CONCLUSIONS: Arterial pulse-contour analysis is easy to use and minimally invasive, thus qualifies as a reliable routine monitoring tool during minimally invasive coronary surgery with tissue stabilizers.
Aged↗
Robotically assisted endoscopic coronary artery bypass procedures without cardiopulmonary bypass.
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Adult↗
Use of the voice-controlled and computer-assisted surgical system ZEUS for endoscopic coronary artery bypass grafting.
OBJECTIVE: With the aim of performing a completely endoscopic coronary bypass anastomosis, we have undertaken an experimental and clinical study using robotic instrumentation and voice-controlled camera guidance. METHODS: The ZEUS Robotic Surgical System (Computer Motion Inc, Goleta, Calif) 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) positions the endoscope via voice control. PHASE I: In a phantom model, vascular grafts were anastomosed to the left anterior descending coronary artery (LAD) of 50 pig hearts with either 2- or 3-dimensional visualization. PHASE II: In 6 dogs (FBI 20-25 kg) the left internal thoracic artery (LITA) was harvested endoscopically. Then the animals were placed on an endovascular cardiopulmonary bypass system (Port-Access, Heartport, Inc, Redwood City, Calif). Anastomosis of the LITA to the LAD was performed endoscopically with the telemetric ZEUS instruments. Flow rates through the LITA were measured by Doppler analysis. PHASE III: Two patients were operated on with the ZEUS system. After endoscopic harvesting of the LITA and cardiopulmonary bypass with the Port-Access system, the bypass graft (LITA-LAD) was anastomosed endoscopically with the ZEUS system through three thoracic ports. RESULTS: In the dry laboratory, the time range required for the robotically assisted coronary anastomosis was 35 to 60 minutes with 2-dimensional visualization and 16 to 32 minutes with 3-dimensional visualization. In the animal experiments, the median time for endoscopic harvesting of the LITA was 86 minutes (range 56-120 minutes) and for the anastomosis, 42 minutes (range 35-105 minutes); flow rates through the LITA ranged between 22 and 45 mL/min. In the clinical cases, preparation times for the LITA were 83 and 110 minutes, respectively, and anastomosis times, 42 and 40 minutes, respectively. Doppler flow rates measured 125 and 85 mL/min, respectively. Both patients had an uneventful follow-up angiogram and postoperative course. CONCLUSIONS: With sophisticated robotic technology, a completely endoscopic anastomosis of the LITA to the LAD is possible, allowing technically precise operations within acceptable time limits.
Anastomosis, Surgical↗
New alternative coronary bypass graft: first clinical experience with an autologous endothelialized cryopreserved allograft.
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Aged↗
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↗
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↗
Surgical versus medical care for postoperative cardiac surgical patients at the general ward.
OBJECTIVES: To shorten hospital stay after cardiac surgery, several risk factors have been defined to identify patients who can be discharged early. These risk factors are dependant on the patient; no studies exist on the influence of the treating physician himself on postoperative patient stay. METHODS: In a university affiliated cardiac surgical clinic we investigated patients who were postoperatively treated either on medical wards with no cardiac surgeon's presence or on a cardiac surgical ward; at both types of wards physicians had several years experience with cardiac surgical patients. Taking several risk factors for postoperative morbidity into account, postoperative length of stay and incidence of wound healing complications have been compared. RESULTS: Within a 3-month period, 84 patients were treated at the cardiac surgical ward, 102 patients at the medical wards. Risk factors for postoperative morbidity were present in 87% of patients, statistically independent of postoperative wards. Although demographic data and median ICU-stay of both patient groups was comparable, the median post-ICU stay was 9 days at the surgical and 13 days at the medical wards (P < 0.0001). Incidence of wound healing complication was higher (19.6%) at the medical wards than at the surgical ward (10.7%), without reaching statistical significance. CONCLUSION: As patients at the respective wards were statistically not different, the difference in post-ICU stay, infection and costs must depend on the treating physicians. As a consequence, postoperative care for cardiac surgical patients in all cases should include direct cardiac surgical participation.
Aged↗
Minimally invasive mitral valve surgery using three-dimensional video and robotic assistance.
Different techniques have been developed for the common goal to minimize surgical trauma for mitral valve surgery. This article focuses on Port-Access (Heartport, Inc, Redwood City, CA) mitral valve replacement or repair (PAMVR) with emphasis on three-dimensional video and robotic assistance. PAMVR was undertaken using a small right anterior minithoracotomy using an endovascular cardiopulmonary bypass (CPB) system. A three-dimensional minicamera allowed visualization of the mitral valve apparatus during this limited access surgery. The three-dimensional (3D) image was displayed inside a helmet just above the real surgical image (VISTA system [Vista, Inc, Westborough, MA]). In addition, the camera was attached to a robotic arm (AESOP [Computer Motion, Inc, Goleta, CA]) that allows stabilization and voice-activated movement of the camera. Fifty patients (16 men, 34 women), aged 36 to 77 years (median, 61.5 years) underwent PAMVR. The underlying diseases were mitral valve insufficiency (n = 36) and combined mitral valve disease (n = 14). With optimal visualization, mitral valve repair was performed in 26 patients with quadrangular resection of the posterior leaflet (n = 26) and repair of the anterior leaflet (n = 3) together with insertion of a posterior or complete anuloplasty ring. The valve was replaced in 24 patients with a mechanical valve prosthesis. Intraoperative and postoperative mortality was 0%. One patient (2%) needed reoperation after a failed repair of an anterior leaflet prolaps. Three-month follow-up was complete in 40 patients, with 34 patients (85%) in New York Heart Association (NYHA) class I and 6 patients in class II. In conclusion, using 3D video and robotic assistance, it was possible to minimize the length of skin incision but at the same time to optimally visualize the whole mitral valve apparatus to perform true Port-Access mitral valve surgery, including complex repair techniques.
Adult↗
Combination therapy with tacrolimus and mycophenolate mofetil following cardiac transplantation: importance of mycophenolic acid therapeutic drug monitoring.
BACKGROUND: Interest has recently been expressed in tacrolimus and mycophenolate mofetil (MMF), two potent immunosuppressants, for a variety of transplant indications. The efficacy of this combination was assessed as primary therapy following cardiac transplantation. METHODS: Forty-five patients were enrolled; 15 into Phase I and 30 to Phase II of the study. Intravenous tacrolimus was administered for 2-3 days to all patients prior to conversion to oral therapy; target blood concentrations were 10-15 ng/mL. Treatment also consisted of steroids and MMF. During Phase I, a fixed 2 g/day dose of MMF was given whilst doses were adjusted according to mycophenolic acid (MPA) plasma levels during Phase II (target range 2.5-4.5 microg/mL). Mean follow-up was 696 +/- 62 days and 436 +/- 88 days for Phases I and II, respectively. RESULTS: Phase I: Patient survival was 100%. Rejection was diagnosed in 66.7% of patients (mean number of episodes per patient 1.33 +/- 1.18). Retrospective analyses indicated that whereas mean MPA plasma levels >3.0 microg/mL were not associated with rejection, no correlation was found with tacrolimus blood concentrations. Phase II: A survival rate of 96.7% was evident, one patient having died from aspergillosis. Diagnoses of rejection were made in 10.0% of patients (0.10 +/- 0.31 episodes per patient) and confounding factors were present in all 3 cases. MPA trough levels were 1.0 +/- 0.3 microg/mL at this time. Resolution was apparent following pulse steroid therapy. Steroids were successfully withdrawn from all patients who completed 6 months' treatment. CONCLUSIONS: Combination therapy with tacrolimus and MMF is associated with suppression of acute myocardial rejection; however, this is dependent upon routine therapeutic drug monitoring.
Adolescent↗
Functional and morphological findings in heart transplant recipients with a normal coronary angiogram: an analysis by dobutamine stress echocardiography, intracoronary Doppler and intravascular ultrasound.
BACKGROUND: Coronary angiography is still the routine screening method for cardiac allograft vasculopathy in most transplant centers. This study was designed to analyze functional and morphologic changes in heart transplant recipients with normal angiographic findings. METHODS: Dobutamine stress echocardiography and intracoronary ultrasound were obtained in 56 patients with a normal coronary angiogram 41+/-31 months after heart transplantation. Intracoronary Doppler flow velocity measurements before and after intracoronary adenosine administration were performed in 34 of 56 patients. Any regional wall motion abnormalities detected by stress echocardiography were regarded as abnormal. By quantitative intracoronary ultrasound analysis using a 6-grade scale, a mean grade of all coronary segments >3.0 was defined as significant intimal hyperplasia. RESULTS: Only 17 patients (30%) showed both a normal dobutamine stress echocardiogram and absence of significant intimal hyperplasia by intravascularultrasound. Abnormal findings were observed in 39 patients (70%): both by dobutamine stress echocardiography and intravascular ultrasound in 22 patients, by intravascular ultrasound alone in 11 patients, and by dobutamine stress echocardiography alone in 6 patients. Coronary flow velocity reserve did not discriminate between patients with normal or abnormal intravascular ultrasound or dobutamine stress echocardiographic findings. CONCLUSIONS: Only a minority of heart transplant patients with a normal coronary angiogram is free of pathological changes, when assessed by intravascular ultrasound and dobutamine stress echocardiography. Coronary flow velocity reserve does not seem useful to further characterize these patients.
Adenosine↗
Functional significance of cardiac reinnervation in heart transplant recipients.
BACKGROUND: There is accumulating evidence of structural sympathetic reinnervation after human cardiac transplantation. However, the functional significance of reinnervation in terms of exercise capacity has not been established as yet; we therefore investigated the influence of reinnervation on cardiopulmonary exercise testing. METHODS: After orthotopic heart transplantation 35 patients (mean age, 49.1 +/- 8.4 years) underwent positron emission tomography with scintigraphically measured uptake of C11-hydroxyephedrine (HED), lung function testing, and cardiopulmonary exercise testing. Two groups were defined based on scintigraphic findings, indicating a denervated group (n = 15) with a HED uptake of 5.45%/min and a reinnervated group (n = 20) with a HED uptake of 10.59%/min. RESULTS: The two study groups did not show significant differences with regard to anthropometric data, number of rejection episodes, preoperative hemodynamics, and postoperative lung function data. The reinnervated group had a significant longer time interval from transplantation (1625 +/- 1069 versus 800 +/- 1316 days, p < .05). In transplant recipients with reinnervation, heart rate at maximum exercise (137 +/- 15 versus 120 +/- 20 beats/min, p = .012), peak oxygen uptake (21.0 +/- 4 versus 16.1 +/- 5 mL/min/kg, p = .006), peak oxygen pulse (12.4 +/- 2.9 versus 10.2 +/- 2.7 mL/min/beat, p = .031), and anaerobic threshold (11.2 +/- 1.8 versus 9.5 +/- 2.1 mL/min, p = .046) were significantly increased in comparison to denervated transplant recipients. Additionally, a decreased functional dead space ventilation (0.24 +/- 0.05 versus 0.30 +/- 0.05, p = .004) was observed in the reinnervated group. CONCLUSIONS: Our study results support the hypothesis that partial sympathetic reinnervation after cardiac transplantation is of functional significance. Sympathetic reinnervation enables an increased peak oxygen uptake. This is most probably due to partial restoration of the chronotropic and inotropic competence of the heart as well as an improved oxygen delivery to the exercising muscles and a reduced ventilation-perfusion mismatching.
Adult↗
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↗