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The authors reflect on the guidelines offered by the Xenotransplantation International Society For heart and Lung (ISHLT) Advisory Board. They inform that initial clinic xenogeneic heart transplantation has provided a solution for heart failure patients suffering from severe right ventricular disfunction and coagulation disorders. They mention that xenotransplantation in non-human primates related to their health is time consuming and costly.

OBJECTIVE Since 1992, homografts have been implanted in our institution. After initial sub-coronary implantation of the homograft, our preferred technique for aortic-valve replacement with homografts became root replacement, which poses a surgical challenge whenever redo procedures are necessary. The aim of the present study was to evaluate the outcome after homograft redo surgery, based on prospective data from the biggest patient cohort in Germany for this procedure. METHODS Between May 1992 and August 2009, 363 adult patients underwent aortic-valve replacement with homografts in our cardiac surgery department. Homograft replacement was indicated in 90 of these 363 patients due to degenerative or infective conditions, and these were analysed. RESULTS In these 73 male and 17 female patients (mean age at redo operation 62.0 years), homograft explantation was necessary due to infection (n = 14) or degeneration (stenosis n = 19, regurgitation > IIo n = 57). Mean time between homograft implantation and redo operation was 8.4 ± 3.6 years (range 0.0-15.5 years). Redo valve replacement through the aorta/homograft was done in 86 cases (valve into homograft wall = 80, total replacement of the homograft = 6) and trans-apical homograft replacement with an Edwards Sapien® Trans-catheter valve in four. Thirteen additional procedures were performed: bypass surgery (n = 1), mitral-valve repair (n = 6), replacement of the ascending aorta (n = 5) and tricuspid-valve repair (n = 1). Thirty-day mortality was 8.9% (n = 8, all of these patients presented with a homograft infection; five patients had a homograft reinfection). Survival rates after 1 and 5 years were 86.0% and 77.4%, respectively. CONCLUSIONS The risk for a redo procedure after aortic-valve replacement with a homograft seems to be acceptable when compared with other prostheses. Mortality was, however, elevated in patients with a homograft infection. Trans-apical procedures are safe and feasible and might be our preferred technique for the future. Valve infections still remain a contraindication for trans- apical procedures. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The right ventricle-to-pulmonary artery (RV-PA) shunt in the Norwood procedure (NP) for children with hypoplastic left-heart syndrome (HLHS) provides stable early hemodynamics and improves survival in many centers. However, lower pulmonary-to-systemic flow ratio causes early cyanosis and may require earlier second-stage procedure. The aim of the study was to present shunt-related results after NP with RV-PA shunt and our technique of RV-PA shunt construction. Methods: Between June 2001 and August 2010, 236 children with HLHS and variants underwent NP with RV-PA shunt, and were operated on by the same surgeon. The medical records were retrospectively reviewed. Results: To date, 180 children at a mean age of 7.0±1.6 months with a mean weight of 6.4±0.9kg underwent second-stage procedure. The mean systemic oxygen saturation before stage 2 operation was 74.8±6.6% and mean arterial partial oxygen pressure was 32.8±6.7mmHg. These two parameters were significantly lower than after NP (p =0.029, p <0.001, respectively). Between stage 1 and 2 operation, three children (1.3%) died due to the shunt obstruction. Four children (1.7%) underwent re-operations due to shunt problems (one of them died), and the other four (1.7%), stent implantation in RV-PA shunt. Two infants (1.1%) developed aneurysm of the right ventricle infundibulum, which was resected during stage 2 without complications. One child required early (before fifth month of age) second-stage procedure due to the shunt obstruction. The patients with right-sided to the neo-aorta course of the RV-PA shunt had significantly more frequent delayed sternal closure after NP than children with left-sided shunt (35.5% vs 14.1%; p =0.008). Conclusions: The RV-PA shunt can be a safe and efficient technique in providing optimal pulmonary blood flow in the children with HLHS after Norwood procedure, performed with minimal rate of complications. In our experience, the use of RV-PA shunt in NP does not require earlier second-stage procedure. [Copyright &y& Elsevier]

Abstract: Objective: Pharmacologic preconditioning represents an attractive myocardial protection strategy. Tumor necrosis factor-alpha plays an important role in myocardial ischemia-reperfusion injury. We aimed to determine the effect of Monophosphoryl lipid A-induced delayed preconditioning on diastolic and systolic left ventricular function and tumor necrosis factor-alpha synthesis during ischemia and reperfusion. Methods: Rats (n=10) were pretreated with Monophosphoryl lipid A (350μg/kg) or vehicle (n=9). Twenty-four hours later, the hearts were isolated and perfused on a Langendorff apparatus. Hemodynamic measurements, tumor necrosis factor-alpha mRNA expression and protein content were studied after stabilization (baseline), after 35min of global ischemia and at 40min of reperfusion. Results: Left ventricular developed pressure and peak rate of left ventricular developed pressure (dP/dt) rise were comparable between the animals in the control and Monophosphoryl lipid A treated groups during baseline but were higher in Monophosphoryl lipid A group at reperfusion (74±4 vs 51±5mmHg, 3340±172 vs 2240±156mmHg/s, respectively, P&#60;0.01). dP/dt fall was significantly lower in the MLA group (2630±225v 1580±210mmHg/s, P&#60;0.01) at 40min of reperfusion as well as end diastolic pressure. Baseline tumor necrosis factor-alpha mRNA (expressed as arbitrary densitometry units) were higher in the Monophosphoryl lipid A group (1.3±0.1 vs 0.5±0.03, P&#60;0.05) but remained constant after ischemia and reperfusion (1.3±0.1 and 1.4±0.03, P=0.2), while further increase was observed in the control group (from 1.0±0.1 to 1.4±0.1, P&#60;0.05). Tumor necrosis factor-alpha protein content from heart effluent in the control group was increased during reperfusion (79±30 and 200±22pg/ml, P&#60;0.05) but was undetectable in the Monophosphoryl lipid A group. Marked TNF-alpha immunostaining of left ventricular tissue was observed only in the control group but no TNF-alpha staining was evident in the Monophosphoryl lipid A treated group at 40min of reperfusion. Conclusion: Monophosphoryl lipid A-induced preconditioning renders the heart more tolerant to ischemia-reperfusion in terms of left ventricular diastolic and systolic function, and prevents tumor necrosis factor-alpha production during ischemia, through aborting the translation phase of tumor necrosis factor-alpha synthesis. [Copyright &y& Elsevier]

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 μg/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. [Copyright &y& Elsevier]

Objectives: There has been frequent report on transcranially detected microembolic signals (HITS) following cardiac surgery using extracorporeal bypass support. The clinical relevance of HITS, however, has yet to be clarified. The incidence of thromboembolic events is increased following mechanical heart valve replacement. The purpose of this study was to quantify postoperative HITS after implantation of two types of prosthetic aortic valves and to compare both types of mechanical valves with respect to the generation of HITS. In addition, HITS rates were correlated with clinical, echocardiographical and laboratory findings. Methods: Forty-two patients following implantation of either a Sorin Biomedica® heart valve (n=22, group A) or a Tekna Duromedics® mechanical valve (n=20, group B) were examined. A group of ten healthy volunteers served as control. Clinical, echocardiographic, carotid artery duplex and laboratory examinations were performed in all patients. A 60 min bilateral transcranial doppler monitoring of the medial cerebral artery (MCA) was also carried out in order to evaluate cerebral blood flow. Results: In group A 14 of 22 patients were positive for HITS (53%), with an average of 16.4±19 HITS/pt.h. In group B 15 of 20 patients were HITS positive (75%) with an average amount of 14.4±24 HITS/pt.h. The incidence of HITS was not significantly different between the two groups. No correlation was seen between the HITS-rate/h and neurological findings, duplex sonographic results, mechanical valve size and anticoagulation regimen (P>0.05). However, a negative correlation was observed between patient age and HITS-rate (P=0.02) as well as between the NYHA degree and HITS-rate (P=0.018). The HITS-rate also correlated with postoperative time (P=0.042). No HITS were detected in the control group. Conclusions: HITS do not correlate with the individual clinical status and, thus, cannot predict the occurrence of neurological deficits in patients following mechanical aortic valve implantation. [Copyright &y& Elsevier]