Early results after pediatric cardiac transplantation with triple immunosuppression therapy

Transplant coronary artery disease in pediatric heart transplant recipients

BACKGROUND

Transplant coronary artery disease (TxCAD) contributes to a large percentage of late morbidity and mortality among adult heart transplant recipients. Intracoronary ultrasound (ICUS) is a sensitive tool in the diagnosis of TxCAD in adult patients and has allowed analysis of factors contributing to disease development. Experience with ICUS in pediatrics, however, has been limited. By using ICUS we sought to determine the overall prevalence of TxCAD in pediatrics and to characterize factors associated with its development in this population.

METHODS

Eighty-six studies were performed in 51 pediatric patients a median of 3.4 years after heart transplantation. Evaluation included angiography and ICUS in 83 and angiography alone in 3 studies. Donor and recipient characteristics were obtained. The ICUS images were analyzed for intimal thickening and compared with coronary angiograms. The presence of any intimal thickening on ICUS was considered TxCAD. An intimal index and point of maximal intimal thickening (MIT) were measured. Vessel disease was graded 0 to 4 based on these results. Four patients had evidence of vasculopathy by angiography, whereas 32 patients (63%) had evidence of intimal proliferation by ICUS. Grade 2 or greater disease was present in 19 (37%) patients. A positive correlation was found when comparing time from transplant with intimal index and MIT (p < 0.001). No other factors were found to predict the development of disease. The overall prevalence of disease was 74% in patients studied at least 5 years after transplant. Intracoronary ultrasound can be performed safely in pediatric patients. Transplant coronary artery disease is common in infants and children after heart transplantation, although its prevalence appears to be less than in adult recipients at similar time intervals. We found no factor other than time from transplant was associated with development of disease.

Rejection with heart failure after pediatric cardiac transplantation

BACKGROUND

Rejection associated with heart failure or death occurs after pediatric cardiac transplantation but has had limited analysis.

METHODS

We analyzed the records of 96 consecutive pediatric cardiac transplant recipients who survived to hospital discharge.

RESULTS

Eighteen patients (19%) experienced 23 episodes of heart failure or death associated with rejection. Univariate analysis demonstrated black race (p = 0.041), transplantation after 12 months of age (p = 0.032), later time after transplantation (p = 0.037), rejection episode in the first year after transplantation (p = 0.001), and history of two or more rejection episodes (p < 0.001) were significantly associated with rejection seen with heart failure. A multivariate regression analysis identified two or more rejection episodes to be the only independent risk factor for the development of rejection with heart failure (odds ratio 20; 95% confidence limits, 4-104; p < 0.0001).

CONCLUSIONS

This study identified pediatric heart transplant recipients with a history of previous rejection episodes to be at a higher risk for symptomatic or fatal rejection. Further studies are needed to determine if intensification of maintenance immunosuppression, long-term rejection surveillance, or both in patients with multiple rejection episodes could reduce morbidity and mortality from rejection.

Dobutamine stress echocardiography for assessing coronary artery disease after transplantation in children

OBJECTIVES

The purpose of this study was to determine the feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography (DSE) for evaluating posttransplant coronary artery disease (TxCAD) in children, and to determine the frequency of selected cardiac events after normal or abnormal DSE.

BACKGROUND

Posttransplant coronary artery disease is the most common cause of graft loss (late death or retransplantation) after cardiac transplantation (CTx) in children. Coronary angiography, routinely performed to screen for TxCAD, is an invasive procedure with limited sensitivity. The efficacy of DSE for detecting atherosclerotic coronary artery disease is established, but is unknown in children after CTx.

METHODS

Of the 78 children (median age 5.7 years, range 3 to 18) entered into the study, 72 (92%) underwent diagnostic DSE by means of a standard protocol, 4.6 +/- 1.9 years after CTx. The results of coronary angiography performed in 70 patients were compared with DSE findings. After DSE, subjects were monitored for TxCAD-related cardiac events, including death, retransplantation and new angiographic diagnosis of TxCAD.

RESULTS

No major complications occurred. Minor complications, most often hypertension, occurred in 11% of the 72 subjects. The sensitivity and specificity of DSE were 72% and 80%, respectively, when compared with coronary angiography. At follow-up (21 +/- 8 months), TxCAD-related cardiac events occurred in 2 of 50 children (4%) with negative DSE, versus 6 of 22 children (27%) with positive DSE (p < 0.01).

CONCLUSIONS

DSE is a feasible, safe and accurate screening method for TxCAD in children. Positive DSE identifies patients at increased risk of TxCAD-related cardiac events. Negative DSE predicts short-term freedom from such events.

Long-term results of triple-drug-based immunosuppression in nonneonatal pediatric heart transplant recipients

BACKGROUND

Few reports document long-term results of pediatric cardiac transplantation in which triple therapy (cyclosporine, azathioprine, and corticosteroids) was the mainstay of immunosuppression. This report details a single center's pediatric transplant experience and analyzes the relative contributions of selected pre/posttransplant risk factors on long-term morbidity and mortality.

METHODS

Retrospective data were collected for all non-neonatal pediatric transplant recipients including: presenting diagnosis, cardiac hemodynamics (particularly pulmonary vascular resistance index), donor ischemic time, occurrence of postoperative infections, episodes of allograft rejection, incidence of posttransplant lymphoproliferative disease or coronary artery disease (CAD), and overall survival. Analysis of single variables and a Cox-proportional hazards model were utilized to determine the impact of pre/posttransplant risk factors on long-term survival.

RESULTS

From 1984 to 1995, 64 patients (mean age, 8.3 years), 46 of whom had cardiomyopathy and 18 who had inoperable complex congenital heart disease, underwent cardiac transplantation and received triple-drug immunosuppression. Orthotopic transplantation was performed unless the pulmonary vascular resistance index remained >6 um2 (despite use of pulmonary vasodilator). One patient required heterotopic transplantation. Average donor ischemic time was 217 min. An average of 1.2 rejection episodes/patient occurred (average follow-up period: 50 months). No patient developed posttransplant lymphoproliferative disease, but 22 patients (34%) developed CAD. Overall survival was 80%, 60%, and 57% at 1, 5, and 10 years, respectively. Of outcome variables analyzed, rejection frequency was significantly increased in patients who subsequently developed CAD, but the presence of CAD was not significantly correlated with mortality.

CONCLUSION

Triple-drug-based immunosuppressive maintenance therapy in pediatric heart transplant recipients results in good long-term graft survival.

Angiographic, intravascular ultrasound and functional findings early after orthotopic heart transplantation

Accelerated graft atherosclerosis is responsible for increased mortality and morbidity among heart transplant recipients. The aim of this in-vivo study was to evaluate coronary atherosclerotic vessel alterations and endothelial function. Seventeen patients (14 males; mean age 49.3 years; range 24 to 69) were studied an average of 11 weeks (range 5 to 21) after heart transplantation because of coronary artery disease (n = 8), dilative cardiomyopathy (n = 7), mitral valve replacement (n = 1) and left atrial metastases of a leiomyosarcoma (n = 1). Mean age of the donor hearts (9 males) was 29 years (range 12 to 55). All recipients underwent biplane ventriculography and coronary angiography. In this study population, a total of 120 coronary segments (main stem, 21; left anterior descending artery, 85; circumflex artery, 14) were analyzed by intravascular ultrasound (20 MHz, 3.5F). In 13 patients, acetylcholine was infused into the proximal left anterior descending artery (10(-8) to 10(-5) M) to evaluate vasomotion within this segment. Regional contraction abnormalities were documented in 2 patients. Nine segments angiographically showed non-critical stenoses (5 patients). Intravascular ultrasound detected 52 cross-sectional areas with a three-layer pattern indicating intimal thickening. Mean circumferential extension of intimal proliferation was 192 degrees, mean intimal thickness 0.35 mm. Only 5 segments of the sonographically pathological cross-sectional areas showed angiographical evidence of atherosclerotic lesions. Intracoronary administration of acetylcholine at doses of 10(-8) and 10(-7) M resulted in vasoconstriction of the examined coronary segment in only 2 patients; the intracoronary application of acetylcholine at doses of 10(-6) and 10(-5) M revealed coronary vasoconstriction in 10 of the total of 13 patients. Using intravascular ultrasound, coronary artery lesions in heart transplant recipients can already be depicted at a very early stage. The abnormal response to acetylcholine in most of the heart recipients is independent of the extent of atherosclerotic vessel abnormalities documented by ultrasound or angiography.