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Pediatric Mechanical Circulatory Support Systems in Latin America

2016; Wiley; Volume: 40; Issue: 10 Linguagem: Inglês

10.1111/aor.12816

1525-1594

Luiz Fernando Canêo, Marcelo Biscegli Jatene,

Cardiac Structural Anomalies and Repair

These devices require extensive human and economic resources. Because the adoption of new technologies should be cost-effective and followed by good results, the health priorities in developing countries, and the status of their health systems are likely to be the limiting factors to incorporate these highly advanced devices. However, an effort should be made to implement MCS programs in countries in epidemiological transition with active pediatric cardiac surgery and transplant programs despite the reduced capabilities. MCS can be used for short- and long-term support. In the short-term group, the most commonly used devices in the pediatric population are extracorporeal membrane oxygenation (ECMO) and centrifugal pumps. ECMO can be effectively used in a variety of settings to provide support to critically ill patients with acute cardiac failure. Although it has become a standard of care in many pediatric cardiac centers, its use is limited to short-term support, and it is not a good option as a bridge to transplantation. Several devices for long-term support are readily available in the USA and Europe for adults, but fewer options are available for children 1, 2. The Berlin Heart EXCOR Pediatric ventricular assist device (VAD) represents the most important tool for long-term support to help pediatric patients of all age groups, from newborns to teenagers, to survive until a donor heart can be identified. The use of these devices has significantly increased the number of children successfully bridged to transplant with an overall survival of 75% at 12 months (including 64% who reached transplantation, 6% who recovered, and 5% who were alive on the device) 3. Historically, in Latin America (LATAM), ECMO was strongly related to cardiac surgery and the first step to start a MCS program 4, 5. Therefore, the ECMO scenario in LATAM can help to understand the difficulties to have a well-established MCS program in this region. Since the first successful utilization of ECMO in 1975 more than 69 000 patients have been supported worldwide, but less than 1% of the Extracorporeal Life Support Organization (ELSO) registry patients are from LATAM countries. In 2012, the Latin-American ELSO's chapter was founded in order to enhance the use of ECMO and its credibility in the region, through the helpful guidelines and expertise of the organization 6. Following ELSO guidelines for training, centers from Chile, Colombia, and Brazil started a standard education process, with the support of experts from the USA, Europe, and Canada. From 2012 to nowadays, the number of registered centers reporting their data to ELSO in LATAM increased from 4 to 33, and the number of scientific publications by LATAM authors augmented almost 10 times. Recently, we published the positive impact of team training and new technology incorporation on the short-term results of patients undergoing postcardiotomy ECMO in pediatric patients and patients with congenital heart disease in our center 7. Colombia also reported a successful cost-effective model of care with nurses as ECMO specialists supported by a multidisciplinary team 8. Although cardiac transplantation (HTX) is considered the best treatment for terminal heart failure, the scarcity of donors is limiting its use. While the International Society of Heart and Lung Transplantation (ISHLT) has shown that the number of adult and pediatric HTX performed worldwide are stable, LATAM reports (Sociedad de Transplante de America Latina y El Caribe Report – 2015 9) are showing an increasing number of HTX in this region. In the last 15 years, only 7976 HTX, less than 12% of the population's needs, were performed in LATAM. Because of its population, Brazil counts for more than half of the total number of HTX performed in LATAM, followed by Argentina and Colombia. The Brazilian National Transplantation System coordinates and regulates perhaps the largest public transplantation program worldwide. Besides the financial support by the public national health system, the number of heart transplants (adults and children) performed in Brazil is only 1.7 per million population (pmp), 4.7 times less than the calculated population needs—a questionable efficiency 10. Pediatric HTX is even less frequent, representing only 0.6 pmp. The number of donations is not the only limiting factor, the quality of heart donors is an important issue for allocation. As a result, less than 17% of the donors' hearts are implanted, suggesting the need of implementing an educational program in the country to improve donor recovery, assessment, and utilization 10. Considering the LATAM as a whole, there are centers doing pediatric HTX in Brazil, Argentina, Colombia, Chile, Uruguay, and Paraguay. Three of these centers represent 50% of all LATAM experience: the Heart Institute at University of São Paulo in Brazil, the Hospital Garrahan in Argentina, and the Fundación Cardiovascular in Colombia 11, 12. Eighty percent of all Brazilian pediatric HTX are performed in three centers located in São Paulo, Fortaleza, and Brasilia, with the Heart Institute at University of São Paulo being the highest volume center in LATAM. The scarcity of donors, particularly for the pediatrics population, and the advanced heart failure of these patients upon arrival in heart transplantation centers, make mandatory the implementation of MCS in selected places in LATAM. The waiting list time in LATAM is two times higher than the USA and one time higher than Europe. Mean waiting list time for transplantation in Brazil is 6 months at least, but in a 5 kg baby is greater than 10 months. The Berlin Heart EXCOR is the most used long-term MCS in this population, with more than 57 devices (48 in Argentina, with 40 of them at the Hospital Gaharran) 13. The use of long-term implantable devices (implantable rotary or axial pumps and the Total Artificial Heart), mainly in the older pediatric population, are currently limited to a very few centers in the region. Interestingly, the volume of HTX and MCS is higher in those countries where the economic support is provided by the public health system, or by their own institutional funds, as seen in Argentina and Colombia. Late referrals for HTX are common in LATAM, with a great number of patients arriving at hospital in a critically ill condition (Pedimacs level 1 or 2), the one with the higher mortality during the transplant waiting list. Therefore, MCS should be anticipated, and every attempt must be made to initiate the support “urgently” rather than “emergently,” before the presence of dysfunction of end organs or circulatory collapse. Comparing MCS used as bridge to HTX in LATAM with Europe and North America, we note a higher number of emergency patients and more biventricular assist device (BVAD) implantations than left ventricular devices (LVADs) explaining the lower 1-year survival ratio (53%) in LATAM when matched to the worldwide results (1-year survival of 73%) (Table 1). The Heart Institute at the University of São Paulo Medical School HTX program began in 1992, and since then we have performed an average of six pediatric HTX per year up to 2010 14. In the last 5 years, we have averaged 17 transplants annually due to the improvements in the state funding for the long-distance organ procurement with air transportation. In Brazil, the transplant program is public but until now, there is no financial support for any kind of MCS. Our MCS program is supported by our institutional fund and restricted to ECMO and centrifugal pump. During the last 5 years, 76 pediatric heart transplantations were performed and 47 MCS were used in 40 patients, pre- and posttransplant. The Berlin Heart EXCOR was used in only three private patients, one of them still on support: a 1-year-old boy waiting 9 months for HTX. Due to the economic constraints imposed by our public health system, we have used only short-term devices to support these patients. We increased the survival ratio to transplantation and to hospital discharge by using centrifugal pumps with apical cannulation as a short-term MCS 15. The same approach has been used by the Fundación Cardiovascular de Colombia since 2010. They utilized centrifugal pumps as a bridge to transplant in 13 children (7 BVAD, 6 LVAD) with an average support of 75 days (longest support 145 days), 8 (61.5%) were successfully transplanted, 1 had partial recovery, and 4 died during or after support (personal communication). Trying to build an affordable long-term MCS for the Brazilian Public Health System, our Bioengineering Division developed a pneumatic paracorporeal ventricular assist device (VAD) using pericardial bovine valves, that was implanted in a series of adult patients 16. The pediatric version of 15, 25, and 50 mL and a complete set of cannulas were tested in acute and chronic animal models (Fig. 1). Soon after the protocol for clinical use was approved, we did the first clinical application in a 6.8 kg boy with dilated cardiomyopathy, with a good initial result, opening an important opportunity for children with different ages and weights in our practice. Similar initiatives are made by Argentina and other centers in Brazil, trying to develop a device with costs compatible with the local reimbursement policy. Still, new challenges remain regarding the incorporation of MCS by LATAM centers, in which education and training required to use these devices is the key issue to achieve similar results to the centers of excellence abroad. International partnership plays an important role in this scenario, where foreign assistance should be adjusted to the local context avoiding dropping a replica of a proven model into an obsolete system 17. Limited resources are a barrier to development of academic, teaching, and cost-effectiveness MCS programs in LATAM. These programs should be designed based on the local needs, centralized in active transplants centers, and financed by the public national systems. Luiz F. Caneo, MD, PhD and Marcelo B. Jatene, MD, PhD Heart Institute, University of São Paulo Medical School, São Paulo, SP, Brazil E-mail: luiz.caneo@incor.usp.br Acknowledgements: The authors thank Guillermo Moreno, MD, from the Hospital Gaharran, Buenos Aires, Argentina and Leonardo Salazar, MD from Fundación Cardiovascular de Colombia, Bucaramanga, Colombia for sharing their data; Berlin Heart for providing data of Pediatric Berlin EXCOR devices implanted in LATAM; and Rodolfo Neirotti, MD, MPA, PhD, for his valuable suggestions and help in preparing the different parts of this manuscript. Biosketch: Dr. Luiz F. Caneo graduated with a degree in medicine and completed his postgraduate education in Cardiovascular Surgery at the University of São Paulo Medical School. He is currently a pediatric cardiovascular surgeon at the Heart Institute, University of São Paulo Medical School and ECMO Center Director. His special interests are pediatric cardiac surgery and adult congenital heart diseases, public health and pediatric cardiovascular surgery systems, quality program and staff training in cardiovascular surgery, and databases in cardiovascular surgery, ECMO, mechanical circulatory support (VADs,) and pediatric heart transplantation. He is also Chairman of ELSO Latin America.