Myosin light chain efflux after heart transplantation in infants and children and its correlation with ischemic preservation time

Total donor ischemic time: relationship to early hemodynamics and intensive care morbidity in pediatric cardiac transplant recipients

OBJECTIVE

Single-center studies have failed to link modest increases in total donor ischemic time to mortality after pediatric orthotopic heart transplant. We aimed to investigate whether prolonged total donor ischemic time is linked to pediatric intensive care morbidity after orthotopic heart transplant.

DESIGN

Retrospective cohort review.

SETTING

Tertiary pediatric transplant center in the United Kingdom.

PATIENTS

Ninety-three pediatric orthotopic heart transplants between 2002 and 2006.

METHODS

Total donor ischemic time was investigated for association with early post-orthotopic heart transplant hemodynamics and intensive care unit morbidities.

RESULTS

Of 43 males and 50 females with median age 7.2 (interquartile range 2.2, 13.0) yrs, 62 (68%) had dilated cardiomyopathy, 20 (22%) had congenital heart disease, and nine (10%) had restrictive cardiomyopathy. The mean total donor ischemic time was 225.9 (sd 65.6) mins. In the first 24 hrs after orthotopic heart transplant, age-adjusted mean arterial blood pressure increased (p < .001), mean pulmonary arterial pressure fell (p = .012), but central venous pressure (p = .58) and left atrial pressure (p = .20) were unchanged. After adjustment for age, primary diagnosis, pre-orthotopic heart transplant mechanical support, and marginal donor factors, longer total donor ischemic time was significantly associated with lower mean arterial blood pressure (p < .001) in the first 24 hrs after orthotopic heart transplant, longer post-orthotopic heart transplant mechanical ventilation (p = .03), longer post-orthotopic heart transplant stay in the intensive care unit (p = .004), and longer post-orthotopic heart transplant stay in hospital (p = .02). Total donor ischemic time was not related to levels of mean pulmonary arterial pressure (p = .62), left atrial pressure (p = .38), or central venous pressure (p = .76) early after orthotopic heart transplant.

CONCLUSIONS

Prolonged total donor ischemic time has an adverse effect on the donor organ, contributing to lower mean arterial blood pressure, as well as more prolonged ventilation and intensive care unit and hospital stays post-orthotopic heart transplant, reflecting increased morbidity.

Association of graft ischemic time with survival after heart transplant among children in the United States

BACKGROUND

Previous studies have found no association between graft ischemic time (IT) and survival in pediatric heart transplant (HTx) recipients. However, previous studies were small or analyzed risk only at the extremes of IT, where observations are few. We sought to determine whether graft IT is independently associated with graft survival in a large cohort of children with no a priori assumptions about where the risk threshold may lie.

METHODS

All children aged <18 years in the U.S. undergoing primary HTx (1987 to 2008) were included. The primary end point was graft loss (death or retransplant) within 6 months. Multivariate analysis was performed to analyze the association between graft IT and graft loss within 6 months after transplant. A secondary end point of longer-term graft loss was assessed among recipients who survived the first 6 months after transplant.

RESULTS

Of 4,716 pediatric HTxs performed, the median IT was 3.5 hours (interquartile range, 2.7-4.3 hours). Adjusted analysis showed that children with an IT > 3.5 hours were at increased risk of graft loss within 6 months after transplant (hazard ratio, 1.3; 95% confidence interval, 1.1-1.5; p = 0.002). Among 6-month survivors, IT was not associated with longer-term graft loss.

CONCLUSIONS

IT beyond 3.5 hours is associated with a 30% increase in risk of graft loss within 6 months in pediatric HT recipients. Although the magnitude of risk associated with IT is small compared with the risk associated with recipient factors, these findings may be important during donor assessment for high-risk transplant candidates.

Successful heart transplantation after 13 hours of donor heart ischemia with the use of HTK solution: a case report

INTRODUCTION

For heart transplantation (HTx), the recommended ischemic time (IT) for donor heart is not to exceed 6 hours. Though Dr Christiaan Barnard used a donor heart with IT of 16 hours, 50 minutes with a portable hypothermic perfusion system in 1981, the recorded IT of donor hearts reported recently is 8 hours, with no adverse effects.

CASE REPORT

The patient, a 14-year-old boy of blood type O, was diagnosed with cardiomyopathy at age 12. In early September 2003, the patient was recommended for HTx. His condition deteriorated 18 days later with low CO, elevated pulmonary vascular resistance, and frequent ventricular tachycardia, further complicated by pneumonia and multiorganism infections, which were contraindications for HTx. On September 22, 2003, a donor heart of blood type O was available 370 km away. Another patient of blood type B with severe heart failure was matched for the HTx. During the intervening time, another donor heart of blood type B became available locally. We matched the type B donor heart to the type B recipient. Since the type O donor heart seemed to be wasted, we performed HTx for the boy. Though preserved for 12 hours in cold cardioplegia, the donor heart was implanted with biatrial anastomosis that took 1 hour. The total IT of this donor heart was 13 hours. The recipient recovered and was discharged 3 months later.

CONCLUSIONS

The IT of 13 hours for this donor heart is believed to be a world record. Our experience demonstrates that preservation time of donor heart may exceed 6 hours.

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.