Acute Embolic Myocardial Infarction and Heart Failure in a Fontan Patient: Recovery with Impella Device and Successful Transplantation

Use of microaxial flow pumps in adolescents

Objectives

The Impella 5.5 has been successfully used in the adult population; however, safety and efficacy data in patients aged less than 18 years are limited.

Methods

Six pediatric patients, aged 13 to 16 years and weighing 45 to 113 kg, underwent axillary artery graft placement and attempted placement of the Impella 5.5 device at our institution between August 2020 and March 2023.

Results

Indications for implantation were heart failure secondary to myocarditis (2), rejection of prior orthotopic heart transplant, idiopathic dilated cardiomyopathy (2), and heart failure after transposition of the great arteries repair. Placement was unsuccessful in a 13.8-year-old female patient due to prohibitively acute angulation of the right subclavian artery, and venoarterial extracorporeal membrane oxygenation cannulation was performed via the axillary graft. In 5 patients with successful Impella 5.5 placement, median duration of support was 13.5 days (range, 7-42 days). One experienced cardiac arrest secondary to coagulation-associated device failure, requiring temporary HeartMate3 implantation. Four patients were bridged to transplant; 3 patients received a transplant directly from Impella 5.5, and 1 patient received a transplant after HeartMate3. The final patient received the HeartMate3 on Impella day 42 and is awaiting transplant.

Conclusions

Although exact size cutoffs and anatomy are still being determined, our experience provides a framework for use of the Impella 5.5 in adolescents.

Coronary artery embolism in a patient with Fontan palliation: a rare complication

Coronary artery embolism is extremely rare in children with Fontan palliation. We report a 10-year-old boy with hypoplastic left heart syndrome post-Fontan procedure who presented with acute onset chest pain and ST-segment changes on electrocardiogram. Cardiac catheterisation revealed coronary artery emboli requiring stent placement. Our case highlights the importance of evaluating chest pain in a systematic manner in Fontan patients as acute coronary artery embolism can be a part of the spectrum of well-known thromboembolic complications.

Percutaneous coronary intervention following Fontan procedure

Fontan procedure is known to increase the risk of thromboembolic events. However, coronary artery thrombotic occlusion is rarely reported in patients with Fontan procedure. We present a case of a 10-year-old boy with hypoplastic left heart syndrome palliated with a Fontan procedure who presented with myocardial infarction secondary to thrombotic occlusion of the left circumflex coronary artery. He underwent successful percutaneous coronary intervention with thrombus aspiration, balloon angioplasty, and stent placement, highlighting the necessity of collaboration between congenital and adult cardiologists to treat acute coronary syndrome among this challenging young population.

Biventricular Impella use in pediatric patients with severe graft dysfunction from acute rejection after heart transplantation

Rejection with severe hemodynamic compromise is a significant source of morbidity and mortality for pediatric heart transplant patients. Traditionally, treatment for these patients includes inotropes and escalation to extracorporeal membrane oxygenation (ECMO) when necessary. There is increasing interest in using percutaneous ventricular assistive devices in the pediatric population as a less invasive alternative to ECMO. We report the largest case series to date of biventricular support using percutaneous Impella devices. Retrospective case series was performed by chart review. Hemodynamics, left ventricular ejection fraction (LVEF), and indices of end organ function were collected before and after Impella placement. A 14-year-old male, 18-year-old male, and 19-year-old female, all status post heart transplant, presented with severely decreased biventricular function due to presumed clinical rejection, requiring maximal inotropic support without improvement. In all the three cases, simultaneous Impella CP and RP devices were placed percutaneously. Prior to implantation, LVEFs were 40%, 23%, and 25%, respectively. Hemodynamics measured invasively prior to device placement showed elevated filling pressures. Adverse events while on support included bleeding, hemolysis, and right femoral arterial dissection during implantation. All patients were successfully weaned from the devices and survived to discharge. The average time of right-sided support and total support was 11 days and 13 days, respectively. After device removal, right-sided pressures and echocardiographic measurements showed improvement in all patients. Bilateral Impella configuration (BiPella) is a viable option for temporary mechanical circulatory support in pediatric patients with significant graft dysfunction.