Experience of Percutaneous Coronary Intervention in the Management of Pediatric Cardiac Allograft Vasculopathy

Use of drug-coated balloon instead of drug-eluting stent for pediatric cardiac allograft vasculopathy

Cardiac allograft vasculopathy (CAV) sometimes leads to restenosis, even after percutaneous transcatheter intervention. Recently, drug-coated balloons (DCBs) have been successfully used to treat coronary artery disease, especially CAVs, in adults. However, no studies have used DCBs in pediatric CAVs. We encountered a patient with CAV who underwent cardiac transplantation for restrictive cardiomyopathy at the age of 2 years. Nine years after the transplantation, severe stenosis of the proximal left anterior descending branch was observed. Considering the patient's young age and the possibility of restenosis, we performed an intervention with DCB. Follow-up conducted 7 months after the intervention showed no restenosis. Cardiac coronary artery lesions following transplantation are more likely to result in restenosis earlier than arteriosclerotic lesions. In pediatric patients, restenosis might require multiple stents and prolonged antiplatelet therapy. Our findings provide evidence supporting the possibility of an effective treatment of CAV in children.

Current state of pediatric cardiac transplantation

Pediatric heart transplantation is standard of care for children with end-stage heart failure. The diverse age range, diagnoses, and practice variations continue to challenge the development of evidence-based practices and new technologies. Outcomes in the most recent era are excellent, especially with the more widespread use of ventricular assist devices (VADs). Waitlist mortality remains high and knowledge of risk factors for death while waiting and following transplantation contributes to decision-making around transplant candidacy and timing of listing. The biggest gap impacting both waitlist and overall survival remains mechanical support options for infants and patients with single ventricle physiology. Though acute rejection has decreased progressively, both diagnosis and management of antibody-mediated rejection has become increasingly challenging and complex, as has the ability to understand the implication of anti-HLA antibodies detected both pre- and post-transplantation-including when and how to intervene. Trends in immunosuppression protocols include more use of induction therapy and steroid avoidance or withdrawal protocols. Common long-term morbidities include renal insufficiency, which can be mitigated with surveillance and renal-sparing strategies, and infections. Functional outcomes are excellent, but significant psychosocial challenges exist in relation to neurodevelopment, non-adherence, and transition from child-centered to adult-centered care. Cardiac allograft vasculopathy (CAV) remains a barrier to long-term survival, though it is more apparent that objective evidence of an impact on the allograft is important with regards to impact on outcomes. Retransplantation is rare in pediatric heart transplant recipients. Pediatric heart transplantation continues to evolve in order to address the challenges of the diverse group of patients that reach end-stage heart failure during childhood.

Percutaneous coronary artery revascularization procedures in pediatric heart transplant recipients: A large single center experience

OBJECTIVES

To describe our experience, at a large pediatric heart transplant center, with percutaneous coronary interventions (PCI) for cardiac allograft vasculopathy (CAV).

BACKGROUND

CAV is a leading cause of late graft failure, mortality, and re-transplantation in pediatric heart transplant (HTx) recipients. Studies of PCI in adult patients have shown some short-term improvements, but no significant change in long-term outcomes. There are limited data on PCI for CAV in pediatric patients. We describe the largest single-center experience to date.

METHODS

We performed a retrospective chart review of all pediatric HTx recipients who underwent PCI for a diagnosis of CAV from 2005 to 2014.

RESULTS

Twenty-three procedures were performed in 13 patients, at a median age of 16.4 years (range 5.6-21.2) and median time from HTx to first PCI of 8.3 years (range 2.9-20.3). Three cases consisted of angioplasty alone, two cases had bare metal stents implanted, and the remaining 18 had drug-eluting stents implanted. There was acute procedural success in all but one case, and there was only one procedure-related complication (rebleeding from access site). During the follow-up interval (median 10.4 months, range 0.2-111.8), 7/13 patients had repeat PCI performed, two patients died (at 1.8 and 5.8 months post-PCI), and five were re-transplanted (range 0.2-18 months post-PCI). Freedom from death or retransplant by Kaplan-Meier analysis was 54% at 1 year.

CONCLUSIONS

PCI can be performed safely and effectively in pediatric HTx recipients with CAV. Similar to the adult experience, there remains a high rate of disease progression and graft failure. © 2016 Wiley Periodicals, Inc.

Percutaneous coronary intervention in pediatric and adolescent patients

OBJECTIVE

Percutaneous coronary intervention (PCI) is commonly used in adult patients with coronary artery disease, but data on PCI in children and adolescents remain limited. Herein, we describe our experience with the use of PCI in pediatric and adolescent patients.

DESIGN

This is a retrospective review.

SETTING

The study was conducted at Mayo Clinic, Rochester, MN.

PATIENTS

All patients ≤18 years old who underwent PCI from 2004 to 2012 were included.

INTERVENTIONS

Intravascular ultrasound and balloon angioplasty were performed in all patients, with subsequent stent placement in 6/7 (86%) procedures.

OUTCOME MEASURES

Residual postintervention stenosis, early procedural morbidity and mortality were the outcome measures.

RESULTS

Overall, seven unique PCI procedures were performed in five patients (four males, mean age 13.2 ± 3.8 years, range 8-18 years). Mean follow-up interval was 2 (0.6-5.5) years. Indications for the procedures included transplant coronary vasculopathy (n = 1), coronary dissection (n = 1), and acute coronary thrombosis/myocardial infarction (n = 1). Additionally, there were two patients (n = 2) who experienced coronary compression as a sequelae of prior heart surgery. Intravascular ultrasound and balloon angioplasty were performed in all patients, with subsequent stent placement in 6/7 (86%) procedures. A total of eight stents were placed (average stent diameter 3 ± 0.5 mm), including six (75%) drug-eluting stents. The targeted coronary artery lesions were successfully treated in all seven procedures. There was no early procedural morbidity or mortality. Two patients were noted to have angiographic evidence of in-stent restenosis at 3 and 15 months postdeployment, respectively, despite treatment with aspirin and clopidogrel.

CONCLUSION

PCI in children and adolescents can be utilized to improve coronary blood flow in a variety of clinical situations. It may be particularly effective in cases of postsurgical coronary compression. Close angiographic follow-up is critical as these patients are at risk for in-stent restenosis.

Heart transplantation in children

In the last 40 years, orthotopic heart transplantation has been established as a realistic treatment strategy for infants and children with severe forms of congenital heart disease and cardiomyopathy. The evaluation, management, and outcomes of these patients have continued to improve. These achievements have advanced pediatric cardiac transplantation and allowed more attention to be focused on improving quality of life after transplantation and reducing the long-term complications.

Percutaneous coronary intervention using drug-eluting stents in pediatric heart transplant recipients

PCI has been used for palliation of CAV in adults, but there are limited data available in children. We sought to evaluate our experience with PCIs for CAV in pediatric heart transplant recipients. Retrospective review of the medical records of all four patients who were diagnosed with CAV, including demographic data and catheterization reports was performed. Of the 149 pediatric heart transplant recipients followed at our institution, 10 were identified with CAV. Four of these 10 underwent 12 PCI procedures for CAV. One donor heart had documented coronary artery disease. Two patients had significant risk factors for coronary artery disease including morbid obesity, hyperlipidemia, and systemic hypertension. PCI involved deployment of bare metal stents (n = 2), paclitaxel-eluting stent (n = 6), and sirolimus-eluting stents (n = 4) with procedural success in all and no early or late mortality. One procedure was complicated by coronary dissection that was successfully treated with stent placement. One patient has been re-transplanted while the other three are not candidates for re-transplantation and have remained asymptomatic as palliation with PCI. PCI using coronary stents is a safe and effective palliative measure for CAV in pediatric heart transplant recipients.

Prevention of pediatric graft coronary artery disease: atorvastatin

Graft coronary artery disease is a significant cause of late graft failure and death after cardiac transplantation. HMG-coenzyme A reductase inhibitors have been used safely in children but their preventative effects against GCAD are not well known. We investigated whether atorvastatin when initiated early could prevent against the development of pediatric GCAD. Pediatric patients (transplanted between October 28, 1992 and July 9, 2004) were stratified into two groups based on whether or not they received atorvastatin early after transplant. Angiograms were reviewed by a single observer blinded to the treatment strategies and clinical outcomes. Actuarial survival method and the Mantel-Cox test were used to assess statistical significance. Freedom from GCAD was higher among those treated with atorvastatin early in the post-transplant course. One, three, and five-yr freedom from GCAD was significantly greater in the early treatment group (97%, 93%, and 93% respectively) compared with the control group (72%, 65%, and 60% respectively, p < 0.005). The early treatment group was also noted for fewer rejection episodes in the first post-transplant year. The use of atorvastatin when initiated early in the post-transplant course appears protective against graft coronary artery disease.

Heart transplantation in pediatric age

Heart transplantation, formerly the final option for terminally ill children, has now become the treatment of choice for a number of serious acquired or congenital cardiac conditions, which cannot be treated conservatively. Nevertheless, several problems remain unsolved. First of all the shortage of donors, mainly in the first months and years of life, which has become more and more significant with time, regardless of the country, religious belief or culture of the people. Secondly, the long-term impact of immunosuppression in a developing organism, and its possible inter-relation with the primary disorder, which leads to intractable heart failure. Whether a heart transplant is a cure or an ongoing disease for both the child and the family is another matter of concern. These and other topics are covered in this article.

Advances in pediatric heart transplantation

PURPOSE OF REVIEW

Heart transplantation has become a reasonable treatment option for pediatric patients with end-stage heart failure or complex congenital cardiac defects not amenable to conventional surgical intervention. This review will summarize the current state of pediatric cardiac transplantation and review recent advances leading to new therapies.

RECENT FINDINGS

Improvements in early mortality after cardiac transplantation have occurred consistently over time since the 1980s, short-term survival rates are high, and most patients enjoy an excellent quality of life with minimal restrictions. The reduction of late mortality is still a major challenge, however, largely as a result of transplant-related coronary artery disease causing chronic graft failure and arrhythmogenic sudden death. Additional causes of morbidity and mortality occurring late after transplantation include renal dysfunction related to chronic immunosuppressive therapy with calcineurin inhibitors (tacrolimus or cyclosporine) and posttransplant lymphoproliferative disorders related to chronic immunosuppression. Newer agents (sirolimus, everolimus) have shown promise in immunosuppressive regimens that may alter the development or progression of long-term complications.

SUMMARY

New immunosuppressive agents allow alterations in drug regimens to minimize renal complications, and may influence the incidence and progression of transplant vasculopathy. Recent studies on posttransplant lymphoproliferative disorders should result in earlier diagnosis and therapy.

Pediatric cardiac transplantation

Pediatric heart transplantation has undergone major changes over the past two decades, marked by a substantial improvement in survival, reduction in posttransplant complications, and enhancement in quality of life for transplant recipients. Actuarial survival has improved substantially in the last decade. Indications for pediatric heart transplant have changed as surgery for complex congenital heart lesions has evolved. There are now left and right ventricular assist devices that are suitable for use in infants as a bridge to transplantation. New immunosuppressive agents have reduced the risk of rejection while minimizing side effects and strategies to reduce the risk of graft coronary disease are beginning to show promise. Finally, true long-term survival for children after heart transplant has now been demonstrated and quality of life is excellent.

Heart and lung transplantation in children

During the past two decades, several advances have resulted in marked improvement in medium-term survival for infants and children undergoing heart transplantation. Unfortunately, progress has been less dramatic in the field of lung and heart-lung transplantation, where there is little evidence of improved outcomes. The procedures remain palliative and all transplant recipients are at risk for the adverse effects of non-specific immunosuppression, including infections, lymphoproliferative disorders, and non-lymphoid malignancies. In addition, current immunosuppressive agents have narrow therapeutic windows and exhibit a wide array of organ toxicities, posing special challenges for the young patient who must endure life-long immunosuppression. New immunosuppressive regimens have lowered the rates of acute rejection but appear to have had relatively little impact on the incidence of chronic rejection, the principal cause of late graft loss. The ultimate goal is to induce a state of donor-specific tolerance, wherein the recipient will accept the allograft indefinitely without the need for long-term immunosuppression. This quest is currently being realised in animal models of solid organ transplantation, and offers great hope for children undergoing heart and lung transplantation in the future.

Ten- and 20-year survivors of pediatric orthotopic heart transplantation

BACKGROUND

Pediatric heart transplantation is entering its third decade, allowing for the first time an analysis of a large group of true long-term survivors, specifically children who have survived > or =10 years post-transplantation.

METHODS

Fifty-two patients < or =18 years, who had undergone heart transplantation at Stanford between August 1974 and June 1993 and survived > or =10 years, were retrospectively reviewed.

RESULTS

Forty (77%) patients are currently alive. Thirteen survived >15 years and 5 >20 years (the longest being 26 years). Actuarial survival was 79.4% at 14 years and 53.1% at 20 years. Cardiomyopathy was the reason for transplantation in 71% and congenital heart disease (CHD) in 29%. At last evaluation, 71% were on a cyclosporine-based regimen and 23% a tacrolimus-based regimen; 33% were steroid-free. Twenty-seven percent were totally free from treatable rejection, 44% developed serious infections, 69% were receiving anti-hypertensives, and 8% required renal transplantation. Neoplasms occurred in 23%, graft coronary artery disease (CAD) in 31%, and 15% required re-transplantation. Of the 12 deaths, CAD was the most common cause (n = 4), followed by non-specific late graft failure (n = 3), infection (n = 2), rejection (n = 1), non-lymphoid cancer (n = 1) and lymphoid cancer (n = 1). Physical rehabilitation and return to normal lifestyle has been nearly 100%.

CONCLUSIONS

Heart transplantation in pediatric patients is compatible with true long-term survival with a growing cohort of children approaching their second and third decades. The gradual constant-phase decrease in survival noted in earlier studies appears to be continuing. Rejection and infection are low but persistent risks after the first years. Graft CAD and non-specific late graft dysfunction are the leading causes of death after 10 years. Rehabilitation is excellent.