Long-term self-management of anticoagulation therapy after mechanical heart valve replacement in outside trial conditions

In this investigation, we hypothesize that quality of oral anticoagulation (OA) and long-term outcome after mechanical heart valve (MHV) replacement with self-management (Self-M) of OA is superior to conventional anticoagulation treatment (Conv-T), even in outside trial conditions. One hundred sixty patients (78.8% aortic valve replacements) were trained in international normalized ratio Self-M and 260 patients (86.2% aortic valve replacements) preferred Conv-T. Mean follow-up was 8.6 ± 2.1 years, representing 3612 patient-years. During follow-up, 37.2% bleedings and 10.6% thromboembolic events were recorded in the Self-M group versus 39.6% bleedings (P = 0.213) and 15.4% thromboembolic events (P = 0.064) in the Conv-T group. Serious adverse events were significantly lower in the Self-M group [grade III bleeding events causing disability or death: 0 versus 4.6% (P = 0.03); grade III thromboembolic events: 0.6 versus 5.0% (P = 0.011)]. Patients with Self-M were significantly more satisfied with their OA management and their quality of life (P < 0.001). Actuarial survival after 1, 5 and 10 years was 100, 99 and 97 with Self-M and 100, 95 and 81% with Conv-T, respectively (P < 0.001). Univariate risk factors for mortality were age (P = 0.008), type of operation (P = 0.021) and conventional OA (P < 0.001). In multivariate analysis, only conventional OA reached significance (P < 0.001). We conclude that in a routine setting under outside trial conditions Self-M of OA improves long-term outcome and treatment quality.

Adeno-associated virus-mediated gene transfer in a rabbit vein graft model

BACKGROUND

Stenoses of venous grafts represent a major limitation in coronary artery bypass surgery. The use of viral vectors to facilitate over-expression of factors within the graft to promote long-term patency is a promising new therapeutic concept. One of the viral vector systems is the adeno-associated virus (AAV); a non-pathogenic single stranded DNA virus, which elicits only low immunological responses.

METHODS AND RESULTS

Recombinant AAV vector coding for beta-galactosidase was produced and transferred ex vivo using intraluminal application to previously harvested rabbit internal jugular vein grafts (n = 8). The 30 min after application, an end-to-end anastomosis of each graft as a bypass to the carotid artery was performed in a previously established rabbit bypass model. X-Gal-staining of the grafts was performed after killing the animals to quantify gene expression. AAV transduction was successful in 100% of the grafts. After 30 days, beta-galactosidase gene expression could be assessed in the medial layer of the graft. Furthermore, no signs of inflammation could be detected.

CONCLUSIONS

These findings suggest that recombinant AAV vectors are an alternative to the widely used adenoviral based vectors. These data support the further use of AAV vectors to overcome intimal hyperplasia after vein graft coronary artery bypass surgery.

ALCAPA with the ectopic orifice at the non-facing sinus: successful anatomic repair by creation of an autologous extrapulmonary tunnel

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital defect. This anomaly leads to a coronary hypoperfusion phenomenon and to substantial left ventricular dysfunction caused by abnormal perfusion of the left ventricle. The optimal surgical management of such cases is not clearly established. Here, we report the successful anatomic repair of ALCAPA arising from the non-facing sinus of Valsalva of the pulmonary artery in a 5-kg patient. In order to perform the repair, we created an autologous extrapulmonary tunnel (from a pulmonary artery flap and autologous pericardium), which we implanted into the ascending aorta. Because of post-cardiotomy heart failure, we implanted an extracorporeal membrane oxygenation device during the same procedure. After recovery of the failing heart, the device was easily ex-planted, and the patient was discharged from the hospital on postoperative day 30.

Tissue engineering of autologous human heart valves using cryopreserved vascular umbilical cord cells

BACKGROUND

Tissue engineering of autologous heart valves with the potential to grow and to remodel represents a promising concept in pediatric cardiovascular surgery. Currently we are exploring the impact of cryopreserved human umbilical cord cells (CHUCCs) for the fabrication of tissue-engineered heart valves for patients diagnosed prenatally with congenital heart lesions, potentially enabling heart valve replacement in the early years of life.

METHODS

Human umbilical cord cells were isolated from vascular segments of umbilical cords and cryopreserved in a cell bank. After 12 weeks the cryopreserved cells were again expanded in culture and characterized by histology, immunohistochemistry, and proliferation assays. Trileaflet heart valve scaffolds were fabricated from a porous polymer (P4HB, Tepha Inc, Cambridge, MA) and sequentially seeded with CHUCCs (n = 10). Five of the heart valve constructs were grown for 7 days in a pulse duplicator and, as a control, five constructs were grown under static cell culture conditions for 7 days. Analysis of all tissue-engineered heart valves included histology, immunohistochemistry, electron microscopy, functional analysis, and biomechanical and biochemical examination.

RESULTS

We found that CHUCCs remained viable after 12 weeks of cryopreservation and showed a myofibroblast-like morphology that stained positive for alpha-actin and fibroblast specific marker. Histology of the tissue-engineered heart valves showed layered tissue formation, including connective tissue between the inside and the outside of the porous scaffold. Immunohistochemistry was positive for collagen (types I, III, and IV), desmin, laminin, and alpha-actin. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer during maturation in the pulsatile flow system. Biochemical examination showed an increase of extracellular matrix formation in constructs after pulsatile flow exposure compared with the static control group. Functional analysis demonstrated a physiological increase of the intracellular Ca2+ concentration of the recultivated cells and the conditioned constructs after stimulation with histamine.

CONCLUSIONS

This study demonstrates in vitro generation of viable and functional human heart valves based on CHUCCs and biomimetic flow culture systems. The CHUCCs demonstrated excellent growth potential and abilities of in vitro tissue formation. These findings suggest the potential benefit of establishing autologous human cell banks for pediatric patients diagnosed intrauterinely with congenital defects that will potentially require heart valve replacement in the early years of life.

Surgical management in paediatric patients with left abnormal subclavian artery and right aortic arch

Left abnormal subclavian artery and right aortic arch is described as a rare cause of dyspnoea and dysphagia in paediatric patients. The optimal surgical management of such cases is not clearly established. We propose a single-stage repair by transection of the patent ductus arteriosus or ligamentum arteriosum and an additional transection of the left abnormal subclavian artery with reimplantation into the common carotid artery.

Stereolithographic Models for Surgical Planning in Congenital Heart Surgery

PURPOSE

Currently we are exploring the impact of using rapid prototyping techniques for surgical planning and intraoperative orientation during the correction of complex congenital malformation.

DESCRIPTION

We studied a patient with a left abnormal subclavian artery and right descending aorta as a rare cause of dyspnea and dysphagia. The patient was examined by magnetic resonance imaging angiography. The image data were visualized and reconstructed. Afterward a replica of the malformation was fabricated using a rapid prototyping machine. In addition, a stereolithographic model of an intracardiac lesion (ventricular septal defect) was fabricated with data obtained from a computed tomographic scan.

EVALUATION

Using data derived from a magnetic resonance imaging angiography or computed tomographic scan linked to proprietary software, we were able to create three-dimensional reconstructions of complex vascular pathology and intracardiac lesions. In addition, we fabricated replicas of congenital malformations using a rapid prototyping machine. The models could be sterilized and taken to the operating room for orientation during the corrective surgical procedure.

CONCLUSIONS

Stereolithographic replicas are helpful for choosing treatment strategies, surgical planning of corrections, and intraoperative orientation, and as demonstrations on life-like models for the patient.

Short-term testing of heart rate variability in heart-transplanted children: equal to 24-h ECG recordings?

INTRODUCTION

Heart rate variability (HRV) is reduced in adults and children after cardiac transplantation. Testing of HRV has been used to assess re-innervation of the cardiac graft; its reliability in ruling out acute graft rejection is still under investigation. This study used a short-term test on HRV in 23 heart and heart-lung transplanted children and adolescents and compared the results with 24-h ECG recordings.

PATIENTS AND METHODS

Twenty-three subjects (16.3+/-4.2 yr; 10 females) underwent a 10-min HRV test at two occasions and one 24-h ECG. HRV was calculated according to the time domain method (RR interval, standard deviation of RR interval) and the frequency domain method (total power, LF and HF for assessment of sympathovagal modulation of heart rate).

RESULTS

Correlation between the short-term tests and 24-h ECG was high with regard to the frequency domain analysis of HRV. Correlation was less pronounced in the time domain method.

CONCLUSIONS

In heart and heart-lung-transplanted children and adolescents, due to reduced overall HRV short-term testing may give as reliable data as 24-h ECG. Therefore, especially when power spectral analysis has to be performed as a longitudinal assessment of re-innervation of the cardiac graft, short-term testing may offer an easily applicable and non-invasive diagnostic tool. Further studies are warranted to investigate whether HRV testing may contribute to rule out acute graft rejection.

Late-onset Tacrolimus-associated Cerebellar Atrophia in a Heart Transplant Recipient

Tacrolimus is a macrolide immunosuppressant frequently used after solid-organ transplantation. Moderate and severe neurologic side effects have been reported in patients receiving tacrolimus. Cerebral neurotoxicity is a rare but fatal calcineurin inhibitor-related complication, especially in kidney and liver transplant recipients. Often a reduction or a change in immunosuppressive regimen is the only means of clinical management. Herein we report a case of a 31-year-old man who developed cerebellar atrophia while under immunosuppressive therapy 9 years after heart transplantation. His neurologic constitution ameliorated after an immunosuppressant switch from tacrolimus to sirolimus.

HLA-DR matching improves survival after heart transplantation: is it time to change allocation policies?

BACKGROUND

HLA matching has improved outcome in kidney transplantation but is not considered in current allocation policies in heart transplantation. The aim of this single-center study was to assess the impact of HLA matching on long- term outcome after heart transplantation.

METHODS

The records of 240 consecutive heart transplant recipients (time period 1995 to 2002; mean age 51.8 +/- 11.7 years; mean follow-up 5.9 +/- 1.8 years) were analyzed retrospectively. According to the renal allocation policy, HLA mismatches (MM) on the major antigen loci HLA-A, HLA-B and HLA-DR were calculated, demonstrating 0 to 6 MM. Patients with primary graft failure were excluded from statistical analysis.

RESULTS

Survival analysis revealed a statistically significant impact of HLA-DR MM on survival. Five-year survival was 90% in patients without HLA-DR MM (n = 10), 79% in patients with 1 HLA-DR MM (n = 113), and 68.1% in patients with 2 HLA-DR MM (n = 117) (1 MM vs 2 MM: p < 0.05). Freedom from cardiac allograft vasculopathy after 5 years was 89% in HLA-DR-identical recipients (n = 10), 61% in patients with 1 HLA-DR MM (n = 102), 54% in patients with 2 HLA-DR MM (n = 104). Conventional matching with 6 mismatches over the three major HLA antigen loci revealed a trend toward a higher relative risk for adverse outcome in patients with increased MM.

CONCLUSIONS

HLA-DR matching had a significant impact on survival after heart transplantation (HTx) at our center. In the effort to achieve the best comparative use of scarce donor organs the inclusion of HLA-DR matching into allocation policies might improve long-term outcome after HTx.

Calculating sympathovagal balance from heart rate variability: are there alternatives in adolescents?

OBJECTIVE

Assessing sympathovagal balance by calculating LF/HF-ratio from power spectral analysis (PSA) of heart rate variability (HRV) may be difficult in adolescents as chaotic breathing leads to methodical bias and metronomic breathing is not easy to perform. Diastolic blood pressure variability (dBPV) is less influenced and may therefore offer more stable values for calculations. The present study was performed on 72 paediatric subjects to investigate possible alternative LF/HF-calculations from PSA of HRV and dBPV.

METHODS AND RESULTS

Seventy-two paediatric individuals in three groups: 12 controls, 17 heart- and heart-lung-transplanted children (TX) and 43 adolescents born small for gestational age (SGA). Short-term beat-to-beat HRV and BP-recordings were made supine and during active standing. Ratios calculated: LF/HF from HRV, LF/HF from dBPV, LF-dBPV/HF-HRV and LF-HRV/HF-dBPV. LF/HF from dBPV as well as LF-HRV/HF-dBPV did not correlate with LF/HF-HRV. Correlation of LF/HF from HRV and LF-dBPV/HF-HRV was high especially in TX and in patients with resting heart rate of above 90 beats per minute.

CONCLUSIONS

In adolescents, the ratio of LF-dBPV/HF-HRV may be an alternative method for calculating sympathicovagal balance being less influenced by breathing patterns. In younger patients with elevated resting heart rate, but also in patients with very low HRV such as TX-patients this method could be a supplemental diagnostic tool whenever autonomic nervous control on the cardiocirculatory system has to be assessed.

Preventing cardiac allograft vasculopathy: long-term beneficial effects of mycophenolate mofetil

BACKGROUND

The impact of long-term mycophenolate mofetil (MMF) treatment on the development of cardiac allograft vasculopathy (CAV) after heart transplantation is an area of much recent interest. This study analyzed the effects of various immunosuppressive combinations, including cyclosporine (CsA), azathioprine (Aza), tacrolimus (Tac) and MMF, on the time of onset, extent and progression of CAV.

METHODS

Two hundred seventy-three consecutive heart transplant recipients (mean age: 51.2 +/- 12.2 years; mean follow-up: 6.8 +/- 1.9 years) were examined by coronary angiography on a yearly basis between 1995 and 2003. The extent of CAV was evaluated using a scoring system based on the severity of vessel stenosis. The onset of CAV was analyzed using Kaplan-Meier estimates and the log rank test for four treatment combinations, CsA/Aza (n = 47, 17.2%), CsA/MMF (n = 26, 9.5%), Tac/Aza (n = 62, 22.7%) and Tac/MMF (n = 138, 50.5%), and for the primary and the secondary immunosuppressants alone.

RESULTS

The rate of freedom from CAV at 5 years was 47% with CsA/Aza, 66% with CsA/MMF, 60% with Tac/Aza and 70% with Tac/MMF. After 5 years, the Tac/MMF group showed a significantly lower incidence of CAV than the CsA/Aza group (log rank 7.58, p = 0.0059). CsA (n = 73) was compared with Tac (n = 200) and MMF (n = 164) with Aza (n = 109): the rate of freedom from CAV was 51.2% in CsA patients vs 66.1% in Tac patients (log rank 5.7, p = 0.017), and 54.6% in Aza patients vs 67% in MMF patients (log rank 4.36, p = 0.037). Multivariate Cox regression analysis revealed that MMF decreased the incidence of CAV significantly (p = 0.041). In this patient cohort, Tac or CsA medication was not an independent risk factor for incidence of CAV nor for decreased survival.

CONCLUSIONS

The choice of immunosuppression has an impact on the incidence of CAV. In terms of prevention of CAV, MMF is superior to Aza in either combination. A trend toward improved survival in MMF patients was noted. The lower number of rejection episodes in the MMF groups may have contributed to these results.

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.

Freedom From Graft Vessel Disease in Heart and Combined Heart- and Kidney-transplanted Patients Treated With Tacrolimus-based Immunosuppression

BACKGROUND

In end-stage cardiomyopathy where concomitant chronic renal failure is a contraindication for cardiac transplantation (HTx), simultaneous heart and kidney transplantation (HKTx) may be the only feasible therapeutic option. Due to the increased donor shortage, the clinical outcome of combined HKTx patients on tacrolimus-based immunosuppression was assessed and compared with a group of HTx patients.

METHODS

Three hundred forty-nine HTxs, including 13 (4%) combined HKTxs, were performed since 1995. Two hundred twenty-one HTx and all HKTx recipients received tacrolimus-based immunosuppression. Acute rejection episodes (AREs), infections, renal function and clinical outcome were evaluated. Pre-operative renal diagnoses for HKTx patients included cystic nephropathy (n = 4), glomerulonephritis (n = 4), cytostatica-induced nephropathy (n = 1), chronic rejection after renal transplant (n = 1), reflux nephropathy (n = 2) and chronic calcineurin-inhibitor -induced nephropathy after HTx (n = 1). Twelve patients (92%) were on hemodialysis pre-operatively, 1 underwent implantation of a left ventricular assist device (LVAD) before HKTx.

RESULTS

After 4.7 +/- 2 years, 92% of HKTx compared with 85% of HTx patients had survived (p = 0.42). Acute cardiac rejection episodes were more frequent in HTx than in HKTx patients (0.04 +/- 0.09 vs 0.02 +/- 0.04 ARE/100 patient-days; p = 0.07). Incidence of infection was comparable (0.3 +/- 0.2 vs 0.5 +/- 0.4 infection/100 patient-days). Freedom from transplant vasculopathy was 100% in the HKTx group compared with 71% in the HTx group after 4 years (p = 0.04).

CONCLUSIONS

Tacrolimus-based immunosuppression yields promising long-term results in HKTx and HTx. The incidence of transplant vasculopathy seems to be lower after HKTx than after HTx. If these results are secondary to a protective effect of tacrolimus-induced tolerance or of tolerance-associated co-transplantation they will need to be investigated in prospective multicenter trials.

The Need for a Tailored Immunosuppression in Older Heart Transplant Recipients

Advanced recipient age is considered a relative contraindication for heart transplantation because it might be associated with increased morbidity and mortality. We analyzed 349 consecutive heart transplantations performed at our institution from 1995 to 2002 (n = 349, mean follow-up 3.5 +/- 2.5 years). The survival rate was lower in older recipients. Less chronic rejection but increased risk for infectious complications, renal failure and neoplasms indicate the need for decreased immunosuppression and effective infection prophylaxis in older recipients.

Mechanical Circulatory Support in Infants and Adults With the MEDOS/HIA Assist Device

Mechanical circulatory support is successfully applied to patients with low cardiac output. The MEDOS/HIA-System provides pulsatile ventricular assistance for pediatric and adult patients. Our experience with 13 consecutive patients with the MEDOS is reported. Perioperative survival was 84.6%, complications occurred in 61% (31% thrombembolism, 23% rethoracotomy, 7% infections). Mean duration of support was 17.6 +/- 14.6 days (1-45 days). Bilirubin decreased from 3.9 +/- 2.3 to 2.7 +/- 1.6 mg/dL; creatinine from 1.6 +/- 1 to 1.4 +/- 0.8 mg/dL; lactate from 5.8 +/- 4.2 to 1.7 +/- 1.5 (P = 0.027; Wilcoxon). All patients who underwent subsequent heart transplantation (6 of 13; 46%) were discharged from hospital. For 38.5% of the patients no organ offer was received. Mechanical circulatory support with the MEDOS/HIA-System can be performed successfully for bridging to transplantation. Secondary organ functions improve under this pulsatile circulatory assistance. Hemorrhage and thromboembolic events are the most frequent complications.

Mechanical Circulatory Support in Pediatric Patients with the MEDOS Assist Device

Mechanical circulatory support is successfully applied to patients with low cardiac output. The MEDOS-System provides pulsatile ventricular assistance for patients of all age groups, including neonates. We report our experience with seven consecutive pediatric patients with the MEDOS-VAD. The indication was bridge to transplantation in all patients. Mean age was 7.3 +/- 6.5 years (range 0.75-16.9 years) and mean weight was 26.3 +/- 21.7 kg (range 5.9-60 kg). Perioperative survival was 100%; complications occurred in six patients (86%; two cerebral embolism/bleeding, two rethoracotomy, two exchange of pump chamber due to thrombus formation after 4 and 9 days). Mean duration of support was 20.4 +/- 10.8 days (range 6-38 days). Bilirubin decreased from 3.5 +/- 2.6 mg/d to 2.1 +/- 1.2 mg/d. Hospital mortality was three of seven patients who did not receive an organ offer in time. All patients who underwent subsequent heart transplantation (four of seven patients; 57%) were discharged from the hospital. Mechanical circulatory support with the MEDOS-System can be performed successfully in pediatric patients of any age. Secondary organ functions improve under this pulsatile circulatory assistance. Hemorrhage and thromboembolic events are the most frequent complications.

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.

A Low-Flow Adaptation Phase Improves Shear-Stress Resistance of Artificially Seeded Endothelial Cells

INTRODUCTION

The purpose of this study was to evaluate the effect of different adaptation phases on the shear-stress resistance of endothelial cells seeded artificially onto vascular prostheses and biological heart valves.

MATERIAL AND METHODS

Human endothelial cells (EC), fibroblasts (FB), and smooth muscle cells (SMC) were isolated from vena saphena magna pieces and expanded in culture. Group A: 15 polyurethane vascular grafts (20 mm diameter) were seeded with FB and SMC (53 +/- 1.2 million cells), followed by EC seeding (39 +/- 0.9 million cells). Group B: eight stentless porcine valves (Freestyle, Medtronic, USA) were seeded with FB (68 +/- 1.5 million cells) and EC (42 +/- 1.1 million cells). Shear-stress testing was done under pulsatile flow (pulse rate: 80 pulses/min.). Adaptation phase: flow was set to 0.9 +/- 0.3 l/min (systolic pressure: 40 - 50 mm Hg). High flow was 3.2 +/- 0.6 l/min. (systolic pressure: 140 - 160 mm Hg) and lasted over four hours in all groups. The vascular grafts were divided into three groups (n = 5 each): group 1 (high flow immediately), group 2 (adaptation phase of 15 minutes), and group 3 (adaptation phase of 30 minutes). The valves either were given high flow immediately (n = 4) or had an adaptation phase of 30 minutes (n = 4). Specimens were obtained after cell seeding, before, and after perfusion.

RESULTS

A confluent EC layer was achieved on all grafts. After perfusion without adaptation, large defects within the cell layer were found. No FB and SMC were seen at the bottom of these defects. In group B, the defects were largest on the ventricular surface of the leaflets. After an adaptation phase of 15 minutes in group A, only a few defects within the EC layer were detected with a still confluent FB and SMC. After a 30-minute adaptation phase defects within the EC layer were very rare and no interruption of the underlying FB and SMC layer was seen. Immunohistochemical staining for factor VIII and CD31 proved the EC to be viable and staining for collagen IV and laminin revealed the formation of a basement membrane. After perfusion, the specimen also stained positive for eNOS.

CONCLUSION

An adaptation phase of 30 minutes proved to be sufficient to allow artificially seeded endothelial cells to adapt to shear stress. The formation of a basement membrane was of great importance for the maintenance of a confluent EC layer.

Results of Pediatric Cardiac Transplantation - Long-Term Results of a 15-Year Experience

INTRODUCTION

Heart transplantation (HTx) has increasingly become a therapeutic option for end-stage heart failure of any origin in children. Short- and mid-term results are promising. However, long-term outcome has been a matter of concern because of acute or chronic rejection and side effects of immunosuppression. We performed a retrospective study of up to 15-years of follow-up on this patient entity.

METHODS

Between 1988 and 2004, 58 HTx were performed in 55 children (cardiomyopathy (DCM) 32, congenital heart disease (CHD) 23, Re-HTx 3). Mean age was 9.1 +/- 7.2 years (4 days - 17.9 years). Twenty-nine patients had a total of 51 previous operations.

RESULTS

Operative mortality was 4/58 (6.8 %) due to primary graft failure. Late mortality was 7/54 (12.1 %) due to acute rejection (2), pneumonia (2), intracranial hemorrhage (1), suicide (1) and lymphoma (1). Mean follow-up was 5.2 +/- 4.2 years. One-, 5-, and 10-year survival was 86 %, 80 % and 80 %, respectively, and improved significantly after 1995 (92 % and 92 %; p = 0.04). Survival was comparable for DCM and CHD patients (1-year: 88 % vs. 82 %; p = 0.19; 5-years: 84 % vs. 77 %; p = 0.12). Three patients with therapy resistant rejection and assisted circulation required retransplantation and are alive. Freedom from acute rejection was 46 % with primary cyclosporine immunosuppression and 63 % with tacrolimus. Ninety-eight percent of the survivors are at home and in excellent cardiac condition.

CONCLUSION

Pediatric heart transplantation is a curative treatment for DCM and CHD with excellent clinical mid-term results. However, further follow-up is necessary to evaluate long-term side effects of immunosuppressants. Donor shortage remains a problem.

Surgical epicardial left ventricular lead versus coronary sinus lead placement in biventricular pacing☆

OBJECTIVE

Biventricular pacing has demonstrated improvement in cardiac function in treating congestive heart failure (CHF). Two different operative strategies (coronary sinus vs. epicardial stimulation) for left ventricular (LV) pacing were compared.

METHODS

Since April 1999, a total of 86 patients (pts, age: 63+/-10 years) with depressed systolic LV function (mean ejection fraction 24+/-9%), left bundle-branch-block (mean QRS 182+/-22 ms) and congestive heart failure NYHA III or higher were enrolled. For biventricular stimulation coronary sinus (CS) leads were placed in 79 pts. Nine of these devices were converted to surgical epicardial LV-leads, because of CS-lead failure. In 7 patients epicardial LV-leads were initially implanted surgically, accounting for a total of 16 pts with surgical placed epicardial steroid-eluting LV-leads. For these, a limited left-lateral thoracotomy (7+/-4 cm) was used. Thirty-three (38%) pts had an indication for a defibrillator. The mean follow-up time was 16.4+/-15.4 months (0.1-45 months), representing 107.1 patient-years.

RESULTS

In the biventricular pacing mode, QRS duration decreased to 143+/-16 ms (P<0.001). Threshold capture of the CS-leads increased significantly compared to surgically placed epicardial leads (18 month control: 2.2+/-1.4V/0.5 ms vs. 0.7+/-0.3V/0.5 ms), which had no increase in threshold (P<0.001). At the 18 month follow-up 7 CS-leads had a threshold of >4V/0.5 ms vs. epicardial leads which were under 1.1V/0.5 ms, except for one (1.8V/0.5 ms). After CS-lead implantation 25 LV-lead related complications occurred, (failed implantation, CS-dissection, loss of pacing capture, diaphragm stimulation or lead dislodgment), vs. one dislodgement after surgical epicardial lead placement (P<0.05). Correct lead positioning (obtuse marginal branch area) was achieved in all surgical epicardial placements but only in 70% with CS-leads (P<0.03). In the follow up period, 9 pts died (4 cardiac related). Heart transplantation was necessary in 4 pts due to deterioration of the cardiomyopathy.

CONCLUSIONS

Surgical epicardial lead placement revealed excellent long-term results and a lower LV-related complication rate compared to CS-leads. Although, the approach via limited thoracotomy for biventricular pacing is associated with 'more surgery', it is a safe and reliable technique and should be considered as an equal alternative.

Cardiac Transplantation in Pediatric Patients: Fifteen-Year Experience of a Single Center

BACKGROUND

Pediatric heart transplantation is a surgical therapy for dilated cardiomyopathy and for complex congenital heart defects with low pulmonary artery resistance. However, it is still discussed as controversial because of uncertain long-term results. We report our experience with pediatric heart transplantation in a heterogeneous population.

METHODS

Since 1988, 50 heart transplants were performed in 47 patients (30 with dilated cardiomyopathy, 17 with congenital heart disease). Mean age was 9.4 +/- 6.9 years (range, 4 days to 17.9 years). Twenty-three patients had a total of 36 previous operations. Clinical outcome was evaluated retrospectively.

RESULTS

Perioperative mortality was 6% due to primary graft failure. Late mortality (12%) was caused by acute rejection (n = 2), pneumonia (n = 2), intracranial hemorrhage (n = 1), and suicide (n = 1). Mean follow-up was 5.24 +/- 3.6 years. Actuarial 1, 5, and 10 year survival was 86%, 86%, and 80% and improved significantly after 1995 (92% [1 year]; 92% [5 years]). There was no significant difference between patients with dilated or congenital heart disease (1 year: 86% vs 82%; 5 years: 83% vs 74%; 10 years 83% vs 74%; p = 0.62). Three patients with therapy resistant acute or chronic rejection and assisted circulation underwent retransplantation and are alive. Freedom from acute rejection after 5 years was 40% with primary cyclosporine immunosuppression regime and 56% with tacrolimus. Since the introduction of mycophenolate mofetil, freedom from acute rejection increased to 62%. All survivors are at home and in good cardiac condition.

CONCLUSIONS

Pediatric heart transplantation is the treatment of choice for end-stage dilated cardiomyopathy as for congenital heart disease with excellent clinical midterm results. It is a valid alternative to reconstructive surgery in borderline patients. However, further follow-up is necessary to evaluate the long-term side effects of immunosuppressants.

Interleukin-6 and procalcitonin in serum of children undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

The aim of our study was to investigate the systemic inflammatory response in children with congenital heart disease undergoing surgical correction with cardiopulmonary bypass. We wanted to discuss interleukin 6 and procalcitonin as components of the systemic inflammatory response syndrome to cardiopulmonary bypass and evaluate postoperative kinetics of these parameters in case of an uncomplicated course.

METHODS

Procalcitonin and interleukin 6 were determined before and after cardiopulmonary bypass surgery in 37 children on the day of surgery, the first and fourth postoperative day. The increased procalcitonin and interleukin 6 levels were evaluated in relationship to intraoperative variables such as duration of aortic cross clamping, incisional trauma and cardiac bypass temperature.

RESULTS

Peak levels of procalcitonin were detected on the first postoperative day, while interleukin 6 reached its highest values on the day of surgery. In contrast to interleukin 6 the median values of procalcitonin differed significantly between short versus long aortic clamping time and atriotomy versus ventriculotomy. Interleukin 6 reached normal levels on the fourth postoperative day, while procalcitonin was still clearly above normal.

CONCLUSIONS

Serum concentrations of procalcitonin and interleukin 6 were influenced by systemic inflammatory response syndrome following cardiac surgery with cardiopulmonary bypass. Even in case of an uncomplicated course both parameters were elevated for at least four days. While procalcitonin serum concentrations were dependent on aortic clamping time or incisional trauma, interleukin 6 showed no significant relation with these intraoperative variables.

The Aristotle score: a complexity-adjusted method to evaluate surgical results1

OBJECTIVES

Quality control is difficult to achieve in Congenital Heart Surgery (CHS) because of the diversity of the procedures. It is particularly needed, considering the potential adverse outcomes associated with complex cases. The aim of this project was to develop a new method based on the complexity of the procedures.

METHODS

The Aristotle project, involving a panel of expert surgeons, started in 1999 and included 50 pediatric surgeons from 23 countries, representing the EACTS, STS, ECHSA and CHSS. The complexity was based on the procedures as defined by the STS/EACTS International Nomenclature and was undertaken in two steps: the first step was establishing the Basic Score, which adjusts only the complexity of the procedures. It is based on three factors: the potential for mortality, the potential for morbidity and the anticipated technical difficulty. A questionnaire was completed by the 50 centers. The second step was the development of the Comprehensive Aristotle Score, which further adjusts the complexity according to the specific patient characteristics. It includes two categories of complexity factors, the procedure dependent and independent factors. After considering the relationship between complexity and performance, the Aristotle Committee is proposing that: Performance = Complexity x Outcome.

RESULTS

The Aristotle score, allows precise scoring of the complexity for 145 CHS procedures. One interesting notion coming out of this study is that complexity is a constant value for a given patient regardless of the center where he is operated. The Aristotle complexity score was further applied to 26 centers reporting to the EACTS congenital database. A new display of centers is presented based on the comparison of hospital survival to complexity and to our proposed definition of performance.

CONCLUSION

A complexity-adjusted method named the Aristotle Score, based on the complexity of the surgical procedures has been developed by an international group of experts. The Aristotle score, electronically available, was introduced in the EACTS and STS databases. A validation process evaluating its predictive value is being developed.

Sirolimus and mycophenolate mofetil as calcineurin inhibitor–free immunosuppression in a cardiac transplant patient with chronic renal failure

Chronic renal failure triggered by calcineurin inhibitor (CNI)-based immunosuppression is a common complication after cardiac transplantation. Sirolimus and mycophenolate mofetil (MMF) are 2 newer immunosuppressive agents with no documented nephrotoxic side effects. This case report describes a patient with ongoing chronic renal failure 10 months after cardiac transplantation on cyclosporine-based immunosuppressive therapy. Conversion of the immunosuppressive regimen from cyclosporine to sirolimus and MMF resulted in freedom from acute rejection, excellent cardiac graft function and consistently improved renal function. This case illustrates the beneficial potential of sirolimus and MMF as CNI-free and safe long-term immunosuppression in a patient with chronic renal failure after heart transplantation.

Renal recovery after conversion to a calcineurin inhibitor-free immunosuppression in late cardiac transplant recipients

OBJECTIVE

Calcineurin inhibitor (CNI)-related renal failure is a common problem after cardiac transplantation (HTx). The aim of this prospective study was to evaluate the safety and efficacy of a completely CNI-free immunosuppressive regimen [mycophenolate mofetil (MMF) and sirolimus (Sir)] in HTx-recipients with late post-transplant renal impairment.

METHODS

Since 2001, 30 HTx-patients (25 men, 6 women; 0.2-14.2 years after transplantation) with CNI-based immunosuppression and a serum creatinine >1.9 mg/dl were included in the study. Creatinine and cystatin levels were monitored to detect renal function. Conversion was started with 6 mg Sir or 500 mg MMF according to the pre-existing regimen and was continued with the dose adjusted to achieve target trough levels between 8 and 14 ng/ml (Sir) or 1.5 and 4 microg/ml (mycophenolate). Subsequently, the CNIs were tapered down and stopped. Clinical follow-up included endomyocardial biopsies, echocardiography and laboratory studies. Additionally, every HTx-patient treated at our centre between 1996 and 2001 due to chronic renal failure without immunosuppressive conversion and fulfilling the inclusion criteria were retrospectively analysed and acted as control group.

RESULTS

Patient demographics and 1-year survival [93 (conversion) vs 90% (control)] were compared. No acute rejection episode was detected in either group. Renal function improved significantly in the conversion group (creatinine: 3.18+/-0.71 vs 2.22+/-0.79 mg/dl, P=0.001; cystatin pre- vs post-conversion: 2.95+/-1.06 vs 2.02+/-1.1 mg/l, P=0.01). In three patients haemodialysis therapy was stopped completely after conversion. In the control group renal impairment was deteriorating, creatinine increased from 2.44+/-0.8 to 3.28+/-1 mg/dl (P=0.01). In 10 out of 33 patients chronic haemodialysis had to be initiated within 1 year. Although side effects of CNI-free immunosuppression were common (76%), no patient had to be excluded due to adverse effects.

CONCLUSIONS

Conversion from CNI-based immunosuppression to MMF and Sir in HTx-patients with chronic renal failure was safe, preserved graft function and improved renal function.

Mycophenolate mofetil and sirolimus as calcineurin inhibitor-free immunosuppression for late cardiac-transplant recipients with chronic renal failure

BACKGROUND

Calcineurin-inhibitor (CNI)-related renal failure is a common problem after cardiac transplantation (HTx). The aim of this study was to introduce a CNI-free immunosuppressive regimen to HTx recipients with late posttransplant renal impairment and to evaluate the impact of conversion to this new immunosuppression (mycophenolate mofetil [MMF] and sirolimus [Sir]) treatment on renal function.

METHODS AND RESULTS

Thirty-one HTx patients (25 men, 6 women; 0.2-14.2 years after transplantation) with CNI-based immunosuppression and a serum creatinine greater than 1.9 mg/dL were included in the study. Creatinine and cystatin levels were monitored to detect renal function. Mean patient age was 50+/-14 (range 19-74) years. Conversion was started with 6 mg Sir, continued with 2 mg, and the dose was adjusted to achieve target trough levels between 8 and 14 ng/mL. MMF was continued with trough level adjusted (1.5-4 microg/mL). Subsequently, the CNIs were tapered down and stopped. Clinical follow-up (first and every 3 months after conversion) included endomyocardial biopsies, echocardiography, and laboratory studies. Survival was 90% after a mean follow-up of 13+/-95 months. No acute rejection episode was detected during the study period. Renal function improved significantly after conversion: creatinine preconversion vs. postconversion: 3.14+/-0.76 mg/dL vs. 2.14+/-0.83 mg/dL, P =0.001. Cystatin preconversion vs. postconversion: 2.95+/-1.06 mg/L vs. 2.02+/-1.1 mg/L, P =0.01. In three patients, hemodialysis therapy was stopped completely after conversion. Graft function remained stable. Fractional shortening preconversion vs. postconversion: 36.9+/-6% vs. 36.4+/-6%. There were no serious adverse events. One patient had to be excluded because of noncompliance.

CONCLUSIONS

Conversion from CNI-based immunosuppression to MMF and Sir in HTx patients with chronic renal failure was safe, preserved graft function, and improved renal function.