Decision making for mechanical cardiac assist in pediatric cardiac surgery

Current Treatment Options for the Failing Fontan Circulation

The Fontan operation was introduced in 1968. For congenital malformations, where biventricular repair is unsuitable, the Fontan procedure has provided a long-term palliation strategy with improved outcomes compared to the initially developed procedures. Despite these improvements, several complications merely due to a failing Fontan circulation, including myocardial dysfunction, arrhythmias, increased pulmonary vascular resistance, protein-losing enteropathy, hepatic dysfunction, plastic bronchitis, and thrombo-embolism, may occur, thereby limiting the life-expectancy in this patient cohort. This review provides an overview of the most common complications of Fontan circulation and the currently available treatment options.

Options for the failing ventricle in pediatric heart disease

The management of the pediatric patient with the failing ventricle poses its own therapeutic challenges, not least because patient size limits options available. Once medical management has hit its ceiling, attention is turned to surgical options for mechanical support. The approach to these options has to bear in mind that there may be many potential causes for pump failure, and that these occur often in the context of pulmonary hypertension and poor gas exchange. Although extracorporeal life support has been the mainstay of treatment for acute heart failure, in the last decade, attention has been focusing on longer-term options to bridge to recovery or eventual transplant. Added to this are more novel applications of ventricular assist devices, notable in the management of the failing Fontan circulation where there are no perfect solutions. There is growing interest in the use of such devices to power this delicate circulation and extend the functional capacity of patients without resorting to transplantation. In this review article, we explore the role each of these surgical modalities has to play in the management of the child with acute and chronic heart failure, and explore the recent developments in the rapidly growing field of pediatric ventricular assist.

Mechanical circulatory support for end-stage heart failure in repaired and palliated congenital heart disease

Approximately one in one hundred children is born with congenital heart disease. Most can be managed with corrective or palliative surgery but a small group will develop severe heart failure, leaving cardiac transplantation as the ultimate treatment option. Unfortunately, due to the inadequate number of available donor organs, only a small number of patients can benefit from this therapy, and mortality remains high for pediatric patients awaiting heart transplantation, especially compared to adults. The purpose of this review is to describe the potential role of mechanical circulatory support in this context and to review current experience. For patients with congenital heart disease, ventricular assist devices are most commonly used as a bridge to cardiac transplantation, an application which has been shown to have several important advantages over medical therapy alone or support with extracorporeal membrane oxygenation, including improved survival to transplant, less exposure to blood products with less immune sensitization, and improved organ function. While these devices may improve wait list mortality, the chronic shortage of donor organs for children is likely to remain a problem into the foreseeable future. Therefore, there is great interest in the development of mechanical ventricular assist devices as potential destination therapy for congenital heart disease patients with end-stage heart failure. This review first discusses the experience with the currently available ventricular assist devices in children with congenital heart disease, and then follows to discuss what devices are under development and may reach the bedside soon.

Mechanical support availability in pediatric cardiac surgery: program size should not matter

Intractable heart failure may require Extracorporeal Life Support (ECLS) techniques for rescue therapy. Nevertheless, in many small to middle-sized centers in Europe, this valuable resource is not available. In our University pediatric intensive care unit 0.9% of 1360 open-heart surgical patients required mechanical assistance over the latest 9 years with a survival rate of 69.2% and low residual morbidity. This favorable overall outcome suggests that regardless of the program size, it is possible to ensure the availability of efficient mechanical assistance that appears to be fundamental in a center performing surgery for complex congenital or acquired cardiac diseases.

Pediatric ventricular assist devices

Ventricular assist device therapy is continuing to evolve in the practice of pediatric cardiac surgery. Although ECMO is still the most often applied mechanical support for infants and young children, a broader range of pulsatile, paracorporeal, as well as implantable ventricular assist devices are now available for pediatric application. A number of these innovative devices have been developed specifically for pediatric use with miniaturized pumps and optimized cannulas suitable for the entire age range of pediatric patients including neonates. Unlike ECMO, these devices can offer medium- to long-term support and have been successfully utilized as a bridge to transplant as well as a bridge to recovery. This review examines the different types of devices currently available, their clinical indications for use, future devices, and the current results of pediatric ventricular assist device therapy in the treatment of heart failure in the pediatric population.

Recent developments in the perioperative management of the paediatric cardiac patient

PURPOSE OF REVIEW

Survival of infants born with complex cardiac anomalies has dramatically improved, and the growing population of patients with congenital heart disease reaching adulthood has resulted in an increased incidence of long-term complications related to the perioperative period. This review focuses on recent advances in strategies to prevent, detect, treat, or predict early and late complications arising from open heart surgery for congenital heart disease.

RECENT FINDINGS

Aprotinine and recombinant factor VIIa may effectively reduce the risk of excessive perioperative bleeding, and the use of steroids, complement component C4A, heparin-coated circuits, and modified ultrafiltration may play a role in the control of the postoperative inflammatory response. Milrinone is becoming increasingly popular in the prevention and treatment of the reduced postoperative cardiac output, and extracorporeal life support has become a well established and successful form of support for postoperative myocardial dysfunction, even in the functionally univentricular heart. In recent years interest increased in optimizing myocardial protection using contents-differentiated and temperature-differentiated blood cardioplegia and in optimizing cerebral protection using a higher haematocrit during bypass and by using selective regional perfusion in favour of circulatory arrest.

SUMMARY

Hearts can be mended, but salvation of hearts and brains needs further rigorous attention.

Intra-aortic balloon pumping in children undergoing cardiac surgery: an update of the Liverpool experience

OBJECTIVE

Intra-aortic balloon pumping in children remains a rarity. We report our experience in supporting pediatric cardiac surgical patients with intra-aortic balloon pumping.

METHODS

We reviewed the cases of 24 children supported with intra-aortic balloon pumping after cardiac surgery in our institution from 1994 through 2003.

RESULTS

Mean age at the time of the operation was 5.0 +/- 5.6 years (range, 7 days-17.5 years). Ten patients were infants less than 6 months old. Mean weight was 18.9 +/- 18.1 kg (range, 3.5-58.7 kg). Indications for intra-aortic balloon pump deployment were postoperative hemodynamic deterioration (n = 11, 8 survivors), failure to wean off cardiopu(n = 7, 5 survivors), and prophylaxis before weaning off cardiopulmonary bypass (n = 6, 5 survivors). The balloon was inserted through the ascending aorta in infants and through the femoral artery in children. Eighteen children (7 infants) were weaned off the intra-aortic balloon pump successfully (intra-aortic balloon pump survival, 75%). Mean duration of intra-aortic balloon pump support was 121.3 +/- 140.60 hours (range, 8-670 hours). There were 3 post-intra-aortic balloon pump in-hospital deaths (survival to hospital discharge, 62.5%). Severe intra-aortic balloon pump-related complications were mesenteric ischemia in 1 patient and lower limb ischemia requiring intra-aortic balloon pump removal in 1 patient. At a mean follow-up of 85 +/- 31 months (range, 18-124 months), all 15 long-term survivors were alive and well.

CONCLUSIONS

Use of an intra-aortic balloon pump is an effective modality of cardiac support in properly selected pediatric cardiac surgical patients with refractory low cardiac output. It can be safely used in small infants and neonates. In selected cases with known left ventricular dysfunction, there is a place for prophylactic use of an intra-aortic balloon pump.

Mechanical cardiac support in the young with the Berlin Heart EXCOR pulsatile ventricular assist device: 15 years' experience

The pediatric-size pneumatically driven pulsatile extracorporeal ventricular assist device (VAD) Berlin Heart EXCOR (Berlin Heart Mediprodukt GmbH, Berlin, Germany) was introduced into clinical practice by the German Heart Institute Berlin in 1992. Until July 1, 2005, Berlin Heart EXCOR systems have been used for circulatory support in 68 children up to 18 years of age with severe circulatory failure resistant to pharmacologic therapy. These were patients suffering from cardiomyopathy, fulminant myocarditis, end-stage congenital cardiac defects, and acute heart failure following congenital heart surgery. Mean VAD support time was 35 days (range, 0 to 420 days). Forty-two patients (62%) survived to transplantation or after weaning; 37 patients (54%), including eight infants, were discharged home. These results in patients with very advanced disease have improved significantly in recent years because of technical developments and growing experience in the treatment of patients on the device, in postoperative care and optimal timing for VAD implantation. Timely implantation of the Berlin Heart EXCOR in the course of progressive heart failure now appears to be justified because the system has undergone the necessary modifications and the accumulation of clinical knowledge has made its use highly reliable and safe.

Clinical Outcomes of 84 Children with Congenital Heart Disease Managed with Extracorporeal Membrane Oxygenation after Cardiac Surgery

The purpose of our research was to study the clinical outcomes of children with congenital heart disease (CHD) requiring extracorporeal membrane oxygenation (ECMO) support after cardiac surgery at a tertiary care children's hospital. Retrospective review of all patients with CHD who required postcardiotomy ECMO between January 2001 and September 2004 (45 months) was undertaken. Various outcome predictors were tested for any association with survival to hospital discharge using univariate analysis. A total of 84 children were placed on ECMO after CHD surgery; 39 (46.4%) were placed on ECMO in the operating room. Median age of the patients was 128 days (1 day to 5 years) and median weight was 4.53 kg (2-18 kg). Active cardiopulmonary resuscitation was ongoing at the time of cannulation in 27 children (32%). Fifty-two children (61.9) survived > 24 hours after decannulation and 31 (36.9%) survived to discharge. High arterial serum lactate levels at the time of ECMO initiation were strongly correlated with nonsurvival (p = 0.004). Nonsurvivors had longer duration on ECMO than survivors (p = 0.003). The odds of survival dropped significantly after 144 hours (day 6) of ECMO. ECMO support results in improved outcomes in patients who suffered hemodynamic collapse post cardiac surgery. Underlying cardiac lesion, age, weight, gender, initial arterial pH, location of ECMO initiation, need for hemofiltration and placement of ECMO after active ongoing cardiopulmonary resuscitation did not increase the mortality risk. Initial arterial serum lactate level and inability to wean off by 6 days were strongly correlated with nonsurvival.