M.A. Kuhn

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.

The Medium-Term Findings in Coronary Arteries by Intravascular Ultrasound in Infants and Children After Heart Transplantation

OBJECTIVES The study purposes were to determine 1) whether intravascular ultrasound (IVUS) was more sensitive than angiography for the detection of post-transplant coronary artery disease (PTCAD) in pediatric patients; and 2) whether those transplanted as neonates reacted differently than older patients. BACKGROUND Experience with IVUS for the diagnosis of PTCAD in children is limited. METHODS Patients were divided into two groups: those transplanted as neonates (early group) and those transplanted in infancy or childhood (late group). Morphometric analysis was performed, including maximal intimal thickness (MIT) and intimal index (II). Stanford classification was used to grade lesion severity. Acute rejection and cytomegalovirus (CMV) status were correlated with MIT and II. RESULTS Thirty children were studied (early group, n = 13; late group, n = 17). All segments studied were angiographically normal. Mean MIT and mean II were significantly greater in the late group (0.26 +/- 0.14 vs. 0.13 +/- 0.04 mm, p < 0.001 and 0.11 +/- 0.07 vs. 0.07 +/- 0.03 mm, p = 0.04, respectively). There was a significant correlation between MIT and II in those who had acute rejection in the late group. Patients in the late group who were CMV-positive had a significantly higher MIT compared with those in the late group with negative serology (p = 0.04). CONCLUSIONS Intravascular ultrasound was more sensitive than angiography in detecting PTCAD after pediatric heart transplantation. There is a possible role for acute rejection and CMV in the development of PTCAD.

Right coronary artery occlusion as a complication of accessory pathway ablation in a 12-year-old treated with stenting.

We describe a complication of radiofrequency ablation of a posteroseptal pathway that resulted in acute occlusion of a distal right coronary artery in a pediatric patient. The complication was treated with coronary stenting after unsuccessful angioplasty. Cathet. Cardiovasc. Intervent. 46:59–61, 1999.

Usefulness of cardiac transplantation in children with visceral heterotaxy (asplenic and polysplenic syndromes and single right-sided spleen with levocardia) and comparison of results with cardiac transplantation in children with dilated cardiomyopathy

Surgical mortality is high in children with visceral heterotaxy (VH), particularly if atrioventricular valve insufficiency, ventricular dysfunction, or aortic atresia is present. This study reviews the outcome of cardiac transplantation (CT) in infants and children with VH and congenital heart disease who are at high risk for standard palliative or corrective surgery. We reviewed CT outcomes in 29 children with VH, congenital heart disease, atrioventricular valve insufficiency, ventricular dysfunction, and/or aortic atresia. Median age at CT was 3.1 years. Cardiac surgery had been performed in 20 patients (69%) before CT. Follow-up since CT has been 8.5 ± 2.2 years. Outcomes were compared with 45 children who underwent transplantation for dilated cardiomyopathy. Actuarial graft survival in the VH group at 30 days and 1, 5, and 10 years was 100%, 86%, 68%, and 50%, respectively, compared with 100%, 96%, 83%, and 68% in children who underwent transplantation for dilated cardiomyopathy (p = 0.12). Splenic status, cardiac position, age at CT, number of prior cardiac surgeries, or systemic venous anomalies were not predictors of mortality after CT. Cardiopulmonary bypass and graft ischemic times were longer in the VH group; time on the ventilator after CT, length of hospitalization, and rejection, infection, post-transplant lymphoproliferative disease, and transplant coronary artery disease rates were equal. Thus, CT is a viable alternative therapy for high-risk patients with VH, possibly offering improved survival over standard surgical management.

Cardiac allograft vasculopathy in pediatric heart transplant recipients

Metabolic parameters for coronary allograft vasculopathy (CAV) have not been well defined in children. CAV (by angiography or autopsy) was studied in 337 heart recipients on a cyclosporine‐based steroid‐sparing regimen. Freedom from CAV for all was 79% at 10 years. Fifty‐nine patients (18%) developed CAV at a mean of 6.5 ± 3 years post‐transplant. First year rejections were significantly higher in CAV, mean 2.3 vs. 1.4, P = 0.003, odds ratio (OR) 1.8. Rejection with hemodynamic compromise beyond 1 year post‐transplant was associated with CAV, P < 0.001, OR 8.4. There was no significant correlation among human leukocyte antigen DR (HLA DR) mismatch, pacemaker use or homocysteine levels and the development of CAV. Maximum cholesterol and low density lipoprotein (LDL) levels were not significantly different. Neither diabetes nor hypertension was significant predictors of CAV on multivariate logistic regression analysis. In conclusion, frequent and severe rejection episodes may predict pediatric CAV. Neither glucose intolerance nor lipid abnormalities appeared to alter risk for CAV in this population.

Moderate acute rejection detected during annual catheterization in pediatric heart transplant recipients.

BACKGROUND Acute rejection commonly occurs within the first year after heart transplantation, and then decreases in frequency with time. Recently, the long-term utility of endomyocardial biopsy during routine annual catheterization has been questioned. The purpose of this study was to retrospectively review the prevalence of biopsy-proven rejection during routine annual catheterization in our patient population, determine whether biopsies late after transplant are useful, and identify factors that correlate with late unsuspected rejection. METHODS Biopsy results from the annual catheterization were evaluated from 1986 to August 2000. The prevalence of moderate rejection was evaluated and compared with the patients immunosuppressive regimen; the prevalence of late rejection; and how late rejection correlated with recipient age, number of first-year rejections and presence of sub-therapeutic cyclosporine. RESULTS A total of 1108 biopsies were performed in 269 children with a mean follow-up of 5 +/- 3 years (median 5 years, range 1 to 11 years). Three-drug immunosuppressive therapy, including steroids, was used in 93 patients. There was a persistent 8% to 10% prevalence of moderate rejection at up to 10 years post-transplantation. Moderate rejection was more likely in patients: (1). on 3-drug immunosuppressive therapy; (2). with a recipient age >1 year; and (3). with a relatively lower cyclosporine level. CONCLUSIONS These data suggest that continued surveillance of pediatric transplant patients for acute rejection is indicated for long-term follow-up.

Outcome of infants with hypoplastic left heart syndrome who undergo atrial septostomy before heart transplantation.

This study evaluated the procedural and long-term outcome of infants who underwent atrial septostomy while awaiting transplant. The results suggest that septostomy improved outcome in these patients although infants needing a transseptal perforation were at higher risk.

Posttransplant recoarctation of the aorta: a twelve year experience

OBJECTIVES This study was undertaken to investigate the incidence of posttransplant recoarctation of the aorta, delineate the mode of presentation, identify risk factors that predict recoarctation and examine the results of intervention for posttransplant recoarctation. BACKGROUND Patients with aortic arch hypoplasia require extended arch reconstruction at transplant, with an inherent possibility of subsequent recoarctation of the aorta. METHODS This was a retrospective review of all children (age <18 years) who underwent cardiac transplantation over a 10-year period. Collected data included pretransplant diagnosis, details of the transplant procedure and posttransplant data including development of recoarctation of the aorta, interventions for recoarctation and the most recent follow-up assessment of the aortic arch. RESULTS Two hundred eighty-eight transplants were performed on 279 children (follow-up = 1,075 patient-years; range 0 to 133 months, median 43.7). Thirty-two of 152 patients (21%) who underwent extended aortic arch reconstruction subsequently developed recoarctation. All but one patient developed recoarctation within 2 years after transplant; 87% were hypertensive at presentation. Of 30 patients who underwent intervention for recoarctation (balloon angioplasty [n = 26] and surgical repair of recoarctation [n = 4]), 26 (87%) have remained recurrence-free (follow-up = 133 patient-years; range 8 to 106 months, median 47). CONCLUSIONS The high frequency of recoarctation after cardiac transplantation with extended aortic arch reconstruction mandates serial echocardiographic evaluation of the aortic arch. Patients typically present with systemic hypertension within the first two years after transplantation. Balloon angioplasty is a safe, effective and durable method of treatment.

Scoring system to determine need for balloon atrial septostomy for restrictive interatrial communication in infants with hypoplastic left heart syndrome

BACKGROUND Restrictive interatrial communication (IAC) causes morbidity and mortality in infants with hypoplastic left heart syndrome awaiting cardiac transplantation. We sought to create a scoring system, based on echocardiographic and clinical findings, to serve as a guide for determining the need for balloon atrial septostomy (BAS). METHODS We retrospectively reviewed echocardiograms of 44 infants with hypoplastic left heart syndrome. Infants were studied from the time of admission to the final end-point of transplantation, Norwood procedure, or death. Seventeen infants underwent BAS for clinical indications of oxygen saturation <80% in room air. Data collected included age at BAS, maximum velocity (V(max)), and IAC diameter throughout the clinical course. We assigned higher IAC scores to smaller IAC diameter, greater V(max) through the IAC, and lower oxygen saturation value. The minimum score was 3, and the maximum score was 9. RESULTS Only 10% of infants with a score <6 at presentation required BAS, whereas 67% of those with scores > or =6 required BAS. Higher IAC scores at presentation were associated with earlier need for BAS (p = 0.04). CONCLUSIONS The IAC scoring system can serve as a reliable clinical guide for identifying infants with hypoplastic left heart syndrome who are likely to require BAS for relief of critically restrictive IAC while awaiting cardiac transplantation.

A Comparative Study of Pediatric Coronary Allograft Vasculopathy between Single Centers in North America and United Kingdom

BACKGROUND Coronary allograft vasculopathy (CAV) is the leading cause of death after pediatric heart transplantation from 1 year postoperation. Anecdotal evidence suggests a difference in the severity of disease between UK and North America. We performed a comparative study using intravascular ultrasound (IVUS). METHODS Consecutive IVUS procedures from a single year were included from each center. Using standardized techniques, measurement of the vessel area, lumen area, and maximal intimamedial thickening (IMT) were performed with calculation of intimal index (II) for each slice. Mean II, mean IMT, and absolute maximum IMT were calculated along the left coronary artery for each patient. Transplant demographics and treatment details were included in the analysis. RESULTS One hundred four patients were included between the 2 centers. Interobserver variability for IVUS analysis was excellent. Patients were aged mean 14.2 (SD 3.3) years at the time of the study and 9.2 (SD 6.0) years earlier post-transplant procedure. UK patients were older, at transplant for a shorter time, and demonstrated more severe CAV. Multiple regression analysis demonstrated the detrimental effect of donor age and time from transplant on CAV severity and benefits of sirolimus use. CONCLUSIONS The data show more severe CAV in the UK cohort despite significantly shorter time post-transplant. Donor age and time post-transplant were associated with more severe CAV and sirolimus use was associated with a reduction in IMT. This study demonstrates a marked difference in the prevalence of CAV in children between UK and North America. The causes are likely to be multifactorial; however, younger donors and recipients have significantly less disease.