Impact of coronary endothelial dysfunction on adverse long-term outcome after heart transplantation.

BACKGROUND: Coronary vasomotor dysfunction is a common finding in cardiac transplant recipients and is an early marker for the development of graft atherosclerosis. The present prospective study tested whether endothelial dysfunction independently predicts cardiovascular-related events and death after heart transplantation (HTx). METHODS: Functional and structural coronary changes were evaluated in 185 consecutive patients 25+/-33 months after HTx. The following potential risk factors for graft survival were assessed at baseline: hypertension, diabetes, dyslipidemia, donor and recipient characteristics (age, gender, cytomegalovirus-infection, human leukocyte antigen-mismatch), pretransplantation diagnosis, ischemic time, treated rejection episodes, immunosuppressive regimens, and medication.The prespecified prospectively defined endpoints were cardiovascular-related events with progressive heart failure, acute myocardial infarction, coronary revascularization, retransplantation, and death. Patients were followed-up for 60+/-17 months. RESULTS: Event-free survival for the entire group was 73% (25 cardiovascular-related events, 25 deaths). Using multivariate analysis, epicardial endothelial dysfunction (relative risk [RR] 1.97; P=0.028), angiographic cardiac allograft vasculopathy (RR 2.11; P=0.023), diabetes (RR 2.32; P=0.022), high serum levels of CyA (RR 3.54; P=0.006) and Tac (RR 6.82; P=0.002), uncommon reasons for transplantation (RR 4.69; P=0.002), and the absence of statin therapy (RR 0.33; P=0.025) were detected as independent predictors of cardiovascular-related events and death. CONCLUSION: This is the first study showing that epicardial endothelial dysfunction independently predicts outcome in HTx patients providing functional and prognostic information that complete angiographic risk factor assessment.

Levosimendan treatment after primary organ failure in heart transplantation: a direct way to recovery?

Heart transplantation is considered nowadays the gold standard in the therapy of chronic and terminal heart insufficiency. Primary organ failure after heart transplantation is a severe complication generally related to prolonged ischemia time, poor quality of the organ, or acute rejection. All these factors can potentially lead to multiorgan failure. Pharmacological and mechanical support for these patients is limited and often related to side effects. Ca sensitizers have been proposed to increase cardiac contractility without altering intracellular Ca levels, thus avoiding the side effects of Ca overload. We report two cases of heart transplanted patients suffering from acute graft failure in the early postoperative period who recovered after intravenous administration of levosimendan, a Ca sensitizer.

Review of major clinical trials with mycophenolate mofetil in cardiac transplantation.

Over the past 10 years, the addition of mycophenolate mofetil (MMF) to combination immunosuppressive regimens in cardiac transplant patients has resulted in significant outcomes benefits. Randomized trials and other studies have demonstrated that the use of MMF is associated with a decreased risk of rejection and improved survival. This article will provide an overview of these trials, as well as those evaluating MMF in renal-sparing regimens and in pediatric cardiac transplant recipients. In addition, emerging evidence demonstrating that MMF may provide long-term benefits in reducing cardiac allograft vasculopathy and those evaluating the role of MMF therapeutic drug monitoring in cardiac transplant recipients will be discussed.

De novo sirolimus with low-dose tacrolimus versus full-dose tacrolimus with mycophenolate mofetil after heart transplantation--8-year results.

BACKGROUND: Although acute cellular rejection after heart transplantation (HTX) can be controlled by full-dose calcineurin inhibitor (CNI)-based immunosuppressive regimens, cardiac allograft vasculopathy (CAV), nephrotoxicity, and malignancy remain ongoing problems. To evaluate the potential beneficial effects of sirolimus and CNI reduction, we compared de novo low-dose tacrolimus and sirolimus with standard tacrolimus and mycophenolate mofetil (MMF)-based immunosuppression after HTX. METHODS: We analyzed a long-term follow-up cohort of 126 patients who underwent HTX during the period 1998-2005 and received either de novo low-dose tacrolimus/sirolimus (lowTAC/SIR; n = 61) or full-dose tacrolimus/MMF (TAC/MMF; n = 64). RESULTS: Freedom from treatment switch was less in the low TAC/SIR group than in the TAC/MMF group (51.7% vs 73.0%, p = 0.038) 8 years after HTX. Freedom from acute rejection was 90.6% in the low TAC/SIR group vs 80.3% in the TAC/MMF group (p = 0.100). There was no difference in freedom from International Society for Heart and Lung Transplantation CAV grade ≥ 1 (55.4% vs 60.0%, p = 0.922), time until CAV diagnosis (4.2 ± 2.0 years vs 3.2 ± 2.4 years, p = 0.087), and CAV severity (p = 0.618). The benefit of reduced early maximum creatinine for low TAC/SIR treatment (1.8 ± 0.9 mg/dl vs 2.4 ± 1.1 mg/dl in TAC/MMF group, p < 0.001) did not continue 5 years and 8 years after HTX (1.4 ± 0.4 mg/dl vs 1.7 ± 1.2 mg/dl, p = 0.333, and 1.6 ± 1.1 mg/dl vs 1.6 ± 0.8 mg/dl, p = 0.957). The trend for superior survival at 5 years with low TAC/SIR treatment (93.1% vs 81.3% in TAC/MMF group, p = 0.051) could not be confirmed after 8 years (84.7% vs 75.0%, p = 0.138). Multivariate analysis at 8 years did not reveal any benefit of low TAC/SIR treatment. CONCLUSIONS: Reduction of de novo CNI did not result in superior long-term renal function. Low-dose mechanistic target of rapamycin inhibition did not achieve any benefit in CAV prevention compared with full-dose TAC/MMF after HTX.

Tacrolimus or cyclosporine: which is the better partner for mycophenolate mofetil in heart transplant recipients?

BACKGROUND: The aim of this single-center study was to investigate whether trough level adjusted mycophenolate mofetil (MMF) is more efficacious in combination with tacrolimus (TAC) or cyclosporine (CsA) and to evaluate the impact of either drug on MMF dosage. METHODS: Sixty patients (TAC, n = 30; CsA, n = 30) undergoing heart transplantation were randomized into a prospective, open-label, controlled trial. Immunosuppression consisted of TAC or CsA in combination with MMF and corticosteroids. Target blood trough levels of TAC, CsA, and mycophenolic acid (MPA) were in the range of 10 to 15 ng/mL, 100 to 300 ng/mL, and 1.5 to 4.0 microg/mL, respectively. Acute rejection episodes (ARE); survival data; and adverse events with a special emphasis on infections, diabetes, hypertension, hypercholesterolemia, and the development of graft vessel disease (GVD) were recorded. RESULTS: Baseline characteristics were well balanced. All patients were successfully withdrawn from corticosteroids within 6 months of transplant. Freedom from acute rejection was significantly higher (P = 0.0001) and the incidence of ARE per 100 patient days significantly lower in the TAC-MMF group than in the CsA-MMF group (0.03 vs. 0.15; P = 0.00007). Overall patient survival during follow-up was similar (93% vs. 90%). To achieve the targeted MPA blood levels, a significantly lower dose of MMF was required for TAC versus CsA patients. After a follow-up time of 2 years, the mean GVD score was 1.85 +/- 3.18 in the TAC-MMF group and 3.95 +/- 4.8 in the CsA-MMF group (P = 0.08). CONCLUSIONS: At the selected doses and target levels for TAC and CsA used in this study, trough level adjusted MMF was more efficacious in combination with TAC for prevention of ARE. Furthermore, CsA patients need significantly more MMF to achieve similar MPA levels.

Beneficial effects of quinaprilat on coronary vasomotor function, endothelial oxidative stress, and endothelin activation after human heart transplantation.

BACKGROUND: We evaluated the potential of angiotensin-converting enzyme inhibition (ACEI) to modulate resting coronary vasomotor tone and endothelial dysfunction, and to decrease vascular oxidative stress and endothelin (ET)-1 activity in human heart transplant recipients. METHODS: Coronary vasomotor responses and transcardiac metabolism of glutathione, oxidized glutathione, and ET-1 were determined before and after quinaprilat infusion in 32 heart transplant recipients. Furthermore, the potential effects of ACEI on endothelial oxidative stress, ET-1 activity, and nitrosoglutathione formation were investigated using endothelial cell cultures. RESULTS: Epicardial diameter increased in response to quinaprilat by 6% +/- 1% (proximal segments; P<0.05) and 14% +/- 3% (distal segments; P<0.01). Coronary flow velocity increased by 2.2 +/- 0.2 (P<0.03). Coronary vasodilation to quinaprilat was negatively correlated with preexisting functional and structural coronary alterations. Quinaprilat selectively improved epicardial vasomotor response in segments with endothelial dysfunction, whereas microvascular endothelial dysfunction was unchanged. Transcardiac glutathione and big ET levels decreased after quinaprilat, whereas oxidized glutathione and ET-1 concentrations remained unchanged. Cell culture studies showed antioxidative effects of quinaprilat, revealed concentration-dependent down-regulation of endothelial ET-1 release, and indicated formation of nitrosoglutathione by quinaprilat. CONCLUSION.: ACE regulates resting coronary vasomotor tone. Quinaprilat reduces vascular oxidative stress and ET-1 activity and mediates formation of nitrosoglutathione, effects that might contribute to long-term vasculoprotective effects of ACEI after heart transplantation.

Short-term angiopeptin therapy and the incidence of graft vessel disease after heart transplantation.

BACKGROUND: Graft vessel disease, the major limitation for long-term success after heart transplantation, is triggered by injury to the graft vessel endothelium, resulting in the expression of adhesion molecules, the migration of leukocytes into the graft, and the release of growth factors. Angiopeptin, a stable analog of somatostatin, is a growth-hormone inhibitor with additional anti-proliferative effects. We evaluated angiopeptin for prevention of graft vasculopathy after cardiac transplantation in the first prospective, randomized, double-blind, clinical trial. METHODS: Thirty-one patients received treatment with either angiopeptin (n = 13) or placebo (n = 18). Patients were randomized according to the presence of hypercholesterolemia, recipient cytomegalovirus-antibody status, and donor age. All patients received standard triple-drug immunosuppression. Angiopeptin 1.5 mg or placebo was given subcutaneously immediately before surgery and twice a day after transplantation from Day 1 to Day 14. Furthermore, 1.5 mg was added to each liter of cardioplegic solution, 1.5 mg was given intravenously during surgery, and another 3 mg was given during the first 6 post-operative hours. During the first post-operative year, angiopeptin 1.5 mg or placebo was added to each treatment for acute rejection (twice a day subcutaneously). Baseline angiography was performed within the first 4 post-operative weeks and annually thereafter. Twenty-three patients each underwent an additional intracoronary ultrasound. RESULTS: One- and 4-year survival rates were comparable: 85% and 85% for the group receiving angiopeptin, and 89% and 78% for the placebo group, respectively. One patient in the control group died of myocardial infarction caused by graft vessel disease. Although the mean number of rejection and infection episodes was similar, the overall incidence of newly occurring graft vessel disease after 2 and 4 years was greater in the control cohort: 9% vs 38% after 2 years and 27% vs 44% after 4 years (p = 0.183, 0.448). Comparison of the results of intracoronary ultrasound performed in a sub-group of patients confirmed that trend: the modified Stanford score, the mean intimal thickness, and the mean intimal index were lower in the angiopeptin group. Again, because of the relatively small number of patients available for evaluation, the difference did not reach statistical significance. CONCLUSIONS: Short-term peri-operative angiopeptin treatment along with additional injections during rejection episodes within the first year resulted in a marked decrease in graft vessel disease 2 and 4 years after heart transplantation. Based on our results, continuous, long-term application of slow-release angiopeptin could significantly decrease or even prevent graft vessel disease.

Ten-year results of a randomized trial comparing tacrolimus versus cyclosporine a in combination with mycophenolate mofetil after heart transplantation.

BACKGROUND: Long-term results of prospective randomized trials comparing triple immunosuppressive strategies combining tacrolimus (TAC) or cyclosporine A (CsA) with mycophenolate mofetil (MMF) and steroids after heart transplantation (HTX) are rarely published. Therefore, we collected long-term follow-up data of an intervention cohort 10 years after randomization. METHODS: Ten-year follow-up data of 60 patients included in a prospective, randomized trial between 1998 and 2000 were analyzed as intention-to-treat (TAC-MMF n=30; CsA-MMF n=30). Baseline characteristics were well balanced. Cardiac allograft vasculopathy (CAV) was graduated in accordance with the new ISHLT classification. RESULTS: Survival at 1, 5, and 10 years was 96.7%, 80.0%, and 66.7% for TAC-MMF and 90.0%, 83.3%, and 80.0% for CsA-MMF (P=ns). Freedom from acute rejection (AR) was significantly higher in TAC-MMF versus CsA-MMF (65.5% vs. 21.7%, log-rank 8.3, P=0.004). Freedom from ISHLT≥CAV1 after 5 and 10 years was in TAC-MMF 64.0% and 45.8%, and in CsA-MMF 36.0% (log-rank 3.0, P=0.085) and 8.0% (log-rank 9.0, P=0.003). No difference in long-term results for freedom from coronary angioplasty or stenting, renal dysfunction, diabetes mellitus, CMV infection, or malignancy was detected. CONCLUSION: Cross-over effects because of treatment switch may result in impairment of significance between the groups. The long-term analysis resulted in a significant difference in manifestation of CAV between the groups after 10 years. Less rejection in the TAC-group might have contributed to the lower incidence of CAV. Superior freedom from AR and CAV in the TAC-MMF group did not result in better long-term survival.

Graft-infiltrating dendritic cells and coronary endothelial dysfunction after human heart transplantation.

BACKGROUND: Indirect allorecognition is involved in chronic transplant rejection. We prospectively characterized graft-infiltrating dendritic cells (DCs) in sequential myocardial biopsies (n = 64; 1 to 24 months after transplantation) from 16 patients after heart transplantation (HTx) and analyzed the relation between graft immune activation and structural and functional coronary changes during follow-up. METHODS: DC invasion (immunostaining) in the human myocardium was detectable early after HTx, increased further during the first year, and decreased constantly thereafter. Also, graft-infiltrating DCs expressed markers of immaturity and maturity and were time-dependently clustered with CD3-positive T cells. RESULTS: Both epicardial and microvascular endothelial dysfunction were associated with elevated CD209-positive DCs at 12 months. CD209 positivity early after HTx was an independent marker for coronary endothelial dysfunction during follow-up. Intimal hyperplasia or angiographic disease during follow-up was not associated with myocardial DC infiltration. CONCLUSIONS: DCs frequently infiltrate the cardiac allograft with a peak during the first post-operative year and time-dependently cluster with T cells. Migratory active graft-infiltrating DCs may serve as a predictor for allograft coronary endothelial dysfunction.

Successful management of antibody-mediated cardiac allograft rejection with combined immunoadsorption and anti-CD20 monoclonal antibody treatment: case report and literature review.

Chronic rejection is still the major limitation of long-term outcome of heart transplant recipients. Several recent studies demonstrated that a not negligible proportion of chronic allograft rejection episodes are not only mediated by T-cell response but also triggered by pre-transplant and de novo post-transplant donor-specific alloantibodies. This points at a fundamental role of humoral immune response mechanisms that contribute to early and late graft failure. This type of rejection is an unsolved problem solid organ transplantation because current immunosuppressive regimens are generally intended to interfere in T-cell signalling pathways. Various options for the removal of circulating alloantibodies and the prevention of alloantibody formation by B-cell depletion have been described. Nevertheless, effective standardized schemes for the treatment of antibody-mediated graft rejection have to be defined. We present a heart transplant recipient with sustained antibody-mediated graft rejection who was successfully managed with a combination treatment consisting of 3 cycles of immunoadsorption and a single-dose administration of the anti-CD20 monoclonal antibody rituximab.

Successful endothelialization of porcine glutaraldehyde-fixed aortic valves in a heterotopic sheep model.

PURPOSE: The purpose of our study was to evaluate the stability of an artificially seeded endothelial cell layer on porcine aortic prostheses under in vivo conditions in the arterial system. DESCRIPTION: Ten female sheep were divided into two groups. Animals of the study group (n = 7) had dissection of their right external jugular vein for cell harvesting. Myofibroblasts and endothelial cells were labelled with PKH-26, seeded onto pretreated (10% citric acid) porcine glutaraldehyde-fixed aortic valves (Freestyle, Medtronic Inc, Duesseldorf, Germany), and the valves were implanted into the descending aorta. Controls (n = 3) received pretreated but unseeded valves. A shunt between the aortic arch and the left atrial appendage ensured systolic or diastolic leaflet motions, or both, that were documented by sonography. After 3 months the valves were explanted. Specimens for scanning electron microscopy and immunohistochemical staining were taken prior to implantation and after explantation. EVALUATION: A neointimal proliferation was detected in the control group. No endothelial cells were found on the leaflets and the sinuses, but erythrocytes and thrombocytes were seen entrapped within the collagen fibers. Thrombus formation was documented macroscopically and histologically on the leaflets and the sinuses. In the study group a confluent endothelial cell layer was documented on the walls and leaflets. Neither neointimal proliferation nor any clots were seen. Some cells were still labelled positively indicating their origin from the initial cell seeding. No dilatation of any prosthesis was observed, but all valves showed slight thickening of the leaflets. CONCLUSIONS: The artificially seeded endothelial cell layers remained stable under in vivo conditions in the arterial system. Biocompatibility of the prostheses seemed to be improved by reduction of thrombogenicity.

Coronary endothelial vasomotor function and vascular remodeling in heart transplant recipients randomized for tacrolimus or cyclosporine immunosuppression.

OBJECTIVES: This study aimed to compare changes in coronary endothelial function, systemic endothelin-1 (ET-1) levels, and vascular remodeling in heart transplant recipients randomized to cyclosporin A (CyA) or tacrolimus (Tac) immunosuppression. BACKGROUND: Functional endothelial abnormalities and intimal thickening are sensitive measures of early cardiac allograft vasculopathy (CAV). METHODS: The randomized, prospective study was performed in two groups of 22 patients, maintained on Tac or CyA and mycophenolate mofetil immunosuppression, 1 and 12 months after heart transplantation. We investigated epicardial luminal diameter, coronary blood flow velocity, and ET-1 plasma levels at 1 and 12 months after transplantation. Structural coronary alterations were determined using intravascular ultrasound. RESULTS: Epicardial vasomotor function at baseline and during follow-up was comparable between the groups. Deterioration of microvascular endothelial function during follow-up was significantly enhanced in the CyA versus Tac group (p < 0.05). Circulating ET-1 concentration increased in the CyA group but significantly decreased over time in the Tac group (CyA +17% vs. Tac -25%; p < 0.05). The time-dependent increase in mean intimal area was significantly enhanced in the CyA versus Tac group, whereas the vessel area significantly increased during follow-up in the Tac compared with the CyA group. CONCLUSIONS: Epicardial endothelial function is comparable between CyA- and Tac-treated patients. Microvascular endothelial function deteriorates more in CyA-treated patients, a finding that correlates with enhanced ET-1 concentration and an increased intimal area during follow-up. The mean vessel area in the Tac group increased over time, indicating positive vascular remodeling. Tac is superior to CyA with respect to microvascular endothelial function, intimal thickening, and vascular remodeling.

Seeding of human endothelial cells on valve containing aortic mini-roots: development of a seeding device and procedure.

PURPOSE: Complete covering of an artificial valvular scaffold with endothelial cells may prevent thromboembolic complications and lead to an excellent biocompatibility. For this purpose, we developed a seeding device for reproducible cell seeding on valve containing aortic roots. DESCRIPTION: Human endothelial cells and fibroblasts were obtained from saphenous vein pieces. Cryopreserved aortic roots (n = 25) were put into an especially developed tube, set on a rotator, and incubated with the cell suspension. The device rotated in two axes (sagittal and axial), ensuring slight movements of the leaflets. The rotation alternated with resting periods, allowing cell attachment to the surface. Different resting periods were tested (groups 1, 2, and 3 were 30, 45, and 60 min, respectively; n = 5 each). Total incubation time was 24 hours followed by further culturing for 6 days. In two further groups (groups 4 and 5; n = 5 each), a modified inlay was used to allow the cell suspension to flow around the entire graft. In group 4 the grafts were again incubated with human endothelial cells; however, in group 5 pre-seeding with autologous fibroblasts was done in addition. Immunohistochemical staining with antibodies against factor VIII, CD31, laminin, collagen IV, and CD90 were done, and scanning electron microscopy was done after initial seeding and after 6 days in culture. EVALUATION: Seeding resulted in homogenous cell layers on the luminal surface of the free walls in all groups. With resting periods of 45 minutes, these results were also obtained on the leaflets, whereas the other resting times resulted in defects of the endothelial cell layer on the cusps. After 6 days under culture conditions, the endothelial cell layers were confluent and viable, with the exception of the leaflets in group 1. With the modified inlay (groups 4 and 5), confluent cell layers were also achieved on the outer surface. In group 5 pre-seeding with autologous fibroblasts resulted in enhanced synthesis of extracellular matrix proteins, as was demonstrated with immunohistochemical staining for collagen IV and laminin. CONCLUSIONS: With this newly developed seeding device, confluent cell layers on valve containing aortic roots were reproducibly achieved. The technique enables further experimental research and even clinical application.

Successful ABO-incompatible heart transplantation in two infants.

In the pediatric age group shortage of donor hearts leads to mortality rates of 30-50% on the waiting list. Because of the immaturity of the immune system of infants, ABO-incompatible heart transplantation may be an option to increase donor availability. We transplanted two infants with blood type O at the age of 7 and 5 months, respectively, with complex congenital heart disease. Intraoperative plasma exchange was performed during cardiopulmonary bypass followed by standard immunosuppression. Both recipients received a blood type A donor organ. Plasma was exchanged up to six times until anti-A antibodies were eliminated. No hyperacute rejection occurred, ventricular function is excellent and there have been no acute rejection episodes up to 4 months after transplantation. Anti-A antibody titers remained low and eventually disappeared. ABO-incompatible cardiac transplantation shows good short-term results in young infants and appears to be a safe procedure to reduce mortality on the waiting list.