Carl W. Chipman

Pediatric arteriovenous extracorporeal membrane oxygenation (ECMO) as a bridge to cardiac transplantation

BACKGROUND Since 1990, extracorporeal membrane oxygenation (ECMO) has been used as a bridge to cardiac transplantation in 47 patients. METHODS A review of the ECMO database, approved by the Arkansas Childrens Hospital institutional review board, forms the basis of this report. We made statistical comparison using Fishers exact probability testing. The ECMO circuitry was a roller occlusion pump with computer-assisted perfusion system technology. RESULTS Thirty-two (68%) patients underwent transcatheter septostomy for cardiac decompression. Diagnosis at presentation was either congenital heart disease (CHD, n = 15) or cardiomyopathy (n = 32). Ages ranged from 1 day to 22 years old (median, 18 months old), and weight ranged from 2.9 to 100 kg (median, 10 kg). The average duration of support was 242 hours (range, 22-1078 hours). Overall long-term survival was 47%, with 16 (34%) patients successfully bridged to cardiac transplantation (of which 9 [56%] survived) and 13 (28%) successfully weaned from ECMO. Patients undergoing ECMO after cardiotomy had 31% survival. Survival was improved significantly (p < 0.02) in patients with cardiomyopathy (59%) vs those with CHD (20%). Patients with cardiomyopathy underwent 8 transplantations with 7 survivors (88%), whereas in the CHD group, there were 8 transplantations with only 2 survivors (25%), p < 0.05. Sub-analysis of the cardiomyopathy group revealed that patients with acute cardiomyopathy in association with documented viral illness had a 75% chance of being weaned from ECMO without undergoing transplantation. Complications during ECMO occurred in 45% of survivors and were more frequent in non-survivors. Infectious complications were most frequent, followed by neurologic complications, technical ECMO problems, and renal insufficiency. CONCLUSIONS Patients with cardiomyopathy has a better prognosis than did those with CHD when using ECMO as a bridge to transplantation or survival. Complications are significant and increase with the duration of support. Extracorporeal membrane oxygenation for salvage and subsequent transplantation in this high-risk group of patients requires critical review. Alternative support options must be developed in the pediatric population that will allow improved outcomes, comparable with outcomes achieved in the adult population.

Extracorporeal Membrane Oxygenation for Cardiac Failure After Congenital Heart Operation

Despite continuing improvement in myocardial protection and surgical technique, the repair of complex congenital heart lesions can result in cardiopulmonary compromise refractory to conventional therapy. In a 29-month period, 24 patients (aged 14 hours to 6 years) were treated with extracorporeal membrane oxygenation (ECMO) 28 times for profound cardiopulmonary failure. Four patients required ECMO after each of two cardiopulmonary bypass procedures. Seventeen patients required ECMO to be initiated in the operating room: 12 (71%) were weaned successfully from ECMO, and 8 (47%) survived. Seven patients had ECMO initiated in the intensive care unit: 6 (86%) were weaned, and 5 (71%) survived. Serial echocardiograms demonstrated substantial recovery of cardiac function in 18 of 21 instances (86%) of ventricular failure from myocardial dysfunction. Overall, 18 of 24 patients (75%) were successfully weaned from ECMO including all 4 who underwent 2 ECMO treatments. We conclude that ECMO can successfully salvage children who have serious cardiopulmonary failure immediately after a congenital heart operation and that long-term survival is possible after two ECMO treatments.

Preliminary single center North American experience with the Berlin Heart pediatric EXCOR device.

For children requiring mechanical circulatory support as a bridge to cardiac transplantation in North America, options previously were limited to extracorporeal membrane oxygenation (ECMO) or centrifugal pump ventricular assist, both of which were suitable for only very short term application and were associated with significant complications and limitations. The Berlin Heart EXCOR ventricular assist device (VAD) was recently introduced into practice in North America to address this deficiency. We report a preliminary single center experience with the EXCOR in 17 children, 13 who received only a left-sided pump and four who required biventricular support. Before EXCOR placement, six patients were on ECMO, and one was on a centrifugal VAD. Eleven children were bridged to transplantation, one was bridged to recovery, and one remains on support. Three children died during support and one died after explantation. There was one late death nearly 2 years after transplant. Complications included stroke in seven patients, two of which were ultimately fatal. Five patients required re-operations for bleeding or evacuation of hematoma. Despite a disappointing rate of neurologic morbidity, our preliminary experience with the EXCOR has been very encouraging.

Standardized Management Improves Outcomes after the Norwood Procedure

BACKGROUND In the past decade, many advances in the care of patients undergoing the Norwood procedure (NP) have been reported, but management remains nonstandardized at many institutions. We studied the impact of a standardized management protocol for neonates undergoing NP. METHODS Care of NP patients has been protocol-driven at our institution since 2005, with routine use of regional low flow perfusion; near infrared spectroscopy; phenoxybenzamine with cardiopulmonary bypass; delayed sternal closure; peritoneal drainage; gastrostomy tubes; postoperative vocal cord assessment; and a home surveillance program of daily weight and oxygen saturation measurement. Patients undergoing NP from 2001 to 2004 (n = 40, group 1), in whom these interventions were only selectively employed, were retrospectively compared with those receiving standardized management from 2005 to 2007 (n = 40, group 2), with endpoints of survival in-hospital and to stage 2 palliation (S2P). Effect of protocol elements on outcome was evaluated by univariate and multivariate analyses. RESULTS Hospital survival (95% vs. 70%, P= .003) and survival to S2P (85% vs. 58%, P= .006) was better in group 2. By univariate analysis, regional low flow perfusion, gastrostomy usage, and near infrared spectroscopy were associated with improved hospital and survival to S2P. In multivariable analysis, gastrostomy usage was associated with improved hospital survival (P= .027) and survival to S2P (P= .049), while our home surveillance program was a predictor of survival to S2P (P= .016). CONCLUSION Protocol-driven management of NP patients was associated with better hospital survival and survival to S2P. Among protocol elements, gastrostomy usage was linked to both improved hospital survival and survival to S2P. Home surveillance was associated with increased survival to S2P.

Single-institution experience with interhospital extracorporeal membrane oxygenation transport: A descriptive study.

Objective: Patients with refractory cardiopulmonary failure may benefit from extracorporeal membrane oxygenation, but extracorporeal membrane oxygenation is not available in all medical centers. We report our institutions nearly 20-yr experience with interhospital extracorporeal membrane oxygenation transport. Design: Retrospective review. Setting: Quaternary care childrens hospital. Patients: All patients undergoing interhospital extracorporeal membrane oxygenation transport by the Arkansas Childrens Hospital extracorporeal membrane oxygenation team. Interventions: Data (age, weight, diagnosis, extracorporeal membrane oxygenation course, hospital course, mode of transport, and outcome) were obtained and compared with the most recent Extracorporeal Life Support Organization Registry report. Results: Interhospital extracorporeal membrane oxygenation transport was provided to 112 patients from 1990 to 2008. Eight were transferred between outside facilities (TAXI group); 104 were transported to our hospital (RETURN group). Transport was by helicopter (75%), ground (12.5%), and fixed wing (12.5%). No patient died during transport. Indications for extracorporeal membrane oxygenation in RETURN patients were cardiac failure in 46% (48 of 104), neonatal respiratory failure in 34% (35 of 104), and other respiratory failure in 20% (21 of 104). Overall survival from extracorporeal membrane oxygenation for the RETURN group was 71% (74 of 104); overall survival to discharge was 58% (61 of 104). Patients with cardiac failure had a 46% (22 of 48) rate of survival to discharge. Neonates with respiratory failure had an 80% (28 of 35) rate of survival to discharge. Other patients with respiratory failure had a 62% (13 of 21) rate of survival to discharge. None of these survival rates were statistically different from survival rates for in-house extracorporeal membrane oxygenation patients or for survival rates reported in the international Extracorporeal Life Support Organization Registry (p > .1 for all comparisons). Conclusions: Outcomes of patients transported by an experienced extracorporeal membrane oxygenation team to a busy extracorporeal membrane oxygenation center are very comparable to outcomes of nontransported extracorporeal membrane oxygenation patients as reported in the Extracorporeal Life Support Organization registry. As has been previously reported, interhospital extracorporeal membrane oxygenation transport is feasible and can be accomplished safely. Other experienced extracorporeal membrane oxygenation centers may want to consider developing interhospital extracorporeal membrane oxygenation transport capabilities to better serve patients in different geographic regions.

Interhospital transport of children requiring extracorporeal membrane oxygenation support for cardiac dysfunction.

OBJECTIVE Many centers are able to emergently deploy extracorporeal membrane oxygenation (ECMO) as support in children with refractory hemodynamic instability, but may be limited in their ability to provide prolonged circulatory support or cardiac transplantation. Such patients may require interhospital transport while on ECMO (cardiac mobile [CM]-ECMO) for additional hemodynamic support or therapy. There are only three centers in the United States that routinely perform CM-ECMO. Our center has a 20-year experience in carrying out such transports. The purpose of this study was twofold: (1) to review our experience with pediatric cardiac patients undergoing CM-ECMO and (2) identify risk factors for a composite outcome (defined as either cardiac transplantation or death) among children undergoing CM-ECMO. DESIGN Retrospective case series. SETTING Cardiovascular intensive care and pediatric transport system. PATIENTS Children (n = 37) from 0-18 years undergoing CM-ECMO transports (n = 38) between January 1990 and September 2005. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A total of 38 CM-ECMO transports were performed for congenital heart disease (n = 22), cardiomyopathy (n = 11), and sepsis with myocardial dysfunction (n = 4). There were 18 survivors to hospital discharge. Twenty-two patients were transported a distance of more than 300 miles from our institution. Ten patients were previously cannulated and on ECMO prior to transport. Thirty-five patients were transported by air and two by ground. Six patients underwent cardiac transplantation, all of whom survived to discharge. After adjusting for other covariates post-CM-ECMO renal support was the only variable associated with the composite outcome of death/need for cardiac transplant (odds ratio = 13.2; 95% confidence interval, 1.60--108.90; P = 0.003). There were two minor complications (equipment failure/dysfunction) and no major complications or deaths during transport. CONCLUSIONS Air and ground CM-ECMO transport of pediatric patients with refractory myocardial dysfunction is safe and effective. In our study cohort, the need for post-CM-ECMO renal support was associated with the composite outcome of death/need for cardiac transplant.

The extracardiac Fontan procedure without cardiopulmonary bypass: technique and intermediate-term results

BACKGROUND The extracardiac Fontan procedure (ECF) usually requires cardiopulmonary bypass (CPB). In this report, the results and techniques of this procedure without CPB at a single institution are presented. METHODS Between August 1992 and December 2001, ECF without CPB was achieved in 24 of 44 patients undergoing an ECF. Mean age at surgery was 5.9 +/- 2.9 years, and mean weight was 20.7 +/- 12.6 kg. Diagnoses were tricuspid atresia in 9 patients, single-ventricle with pulmonary outflow tract obstruction in 7, pulmonary atresia/intact septum in 5, and other complex single-ventricle physiology in 3. Initial palliation was by arterial to pulmonary artery shunt in 21 and pulmonary artery banding in 1. A bidirectional cavopulmonary connection was created in 23 patients. A temporary inferior vena caval-to-atrial shunt was used to complete the procedure without CPB. Median graft size was 16 mm (range 14 to 20 mm). RESULTS There was no early mortality, and 68% of patients were discharged without complications. Complications included persistent cyanosis in 4 patients, persistent pleural effusions in 2 (one chylous), and phrenic nerve injury in 1. Median postoperative hospital stay was 16 days (range 10 to 50) days. At a mean follow-up of 44 +/- 28 months, there was no conduit obstruction. One patient died 11 months postoperatively, and 1 patient received a heart transplant 26 months post-ECF. CONCLUSIONS At intermediate term follow-up, the ECF without CPB appears to be safe and technically reproducible in selected cases. Ongoing follow-up of these patients is necessary to document the theoretical advantages of avoiding CPB.

Intrahospital transport of children on extracorporeal membrane oxygenation: Indications, process, interventions, and effectiveness

Objective: To evaluate indications, process, interventions, and effectiveness of patients undergoing intrahospital transport. Critically ill patients supported with extracorporeal membrane oxygenation are transported within the hospital to the radiology suite, cardiac catheterization suite, operating room, and from one intensive care unit to another. No studies to date have systematically evaluated intrahospital transport for patients on extracorporeal membrane oxygenation. Design: Retrospective cohort analysis. Setting: Cardiac intensive care unit in a tertiary care childrens hospital. Patients: All patients on extracorporeal membrane oxygenation who required intrahospital transport between January 1996 and March 2007 were included and analyzed. Measurements and Main Results: A total of 57 intrahospital transports for cardiac catheterization and head computed tomography scans were analyzed. In 14 (70%) of 20 of patients with cardiac catheterization, a management change occurred as a result of the diagnostic cardiac catheterization. In ten (59%) of 17 patients, bedside echocardiography was of limited value in defining the critical problem. In the interventional group, the majority of transports were for atrial septostomy. In the head computed tomography group, significant pathology was identified, which led to management change. No major complications occurred during these intrahospital transports. Conclusions: Although transporting patients on extracorporeal membrane oxygenation is labor intensive and requires extensive logistic support, it can be carried out safely in experienced hands and it can result in important therapeutic and diagnostic yields. To our knowledge, this is the first study designed to evaluate safety and efficacy of intrahospital transport for patients receiving extracorporeal membrane oxygenation support.

The Midterm Outcomes of Bioprosthetic Pulmonary Valve Replacement in Children

The purpose of this study was to assess the outcomes of bioprosthetic pulmonary valve replacement (PVR) in children. This is a retrospective review of all bioprosthetic PVR in children (≤ 20-year old) between 1992 and 2013 at a single institution. Most outcomes studied included pulmonary valve reintervention and bioprosthetic valve function. A total of 136 bioprosthetic PVRs were identified for 123 patients. The median age and body weight at the time of operation were 13.2 years and 48.4 kg. There were 1 early death and 3 late deaths during the median follow-up of 7.2 years (0-22.0 years). The actuarial transplant-free survival was 97.6% at 10 years. There were 43 bioprosthesis reinterventions with 29 reoperations and 14 catheter-based interventions. The freedom from bioprosthesis reintervention was 89.6% and 55.0% at 5 and 10 years, respectively. Echocardiographic bioprosthesis dysfunction (≥ moderate bioprosthesis insufficiency, ≥ 50 mmHg peak gradient through bioprosthesis, or bioprosthesis endocarditis with vegetation) was found in 57 bioprostheses. The freedom from bioprosthesis dysfunction was 74.0% and 32.8% at 5 and 10 years, respectively. Results from the Cox proportional hazards models showed that age had significant association with freedom from bioprosthesis reintervention and freedom from bioprosthesis dysfunction (P < 0.001 and P = 0.03), whereas bioprosthesis type had nonsignificant association with freedom from bioprosthesis dysfunction (P = 0.068). Bioprosthetic PVR in children had excellent early outcomes but rapidly deteriorating midterm outcomes. Careful and close follow-up are necessary for children with bioprosthesis in the pulmonary position.

Mobile extracorporeal membrane oxygenation

Mobile extracorporeal membrane oxygenation (ECMO) is being offered by select ECMO centers in the United States. Mobile ECMO can be performed for the critically ill patient who is unable to be transported by conventional ambulance transport. This article discusses the logistics and safety considerations associated with mobile ECMO.