Andersons pediatric cardiology 1758

Total Artificial Heart The total artificial heart (TAH; SynCardia) is an implantable biventricular, pneumatic compression device that replaces both ventricles anatomically and mechanically (Video 66.1) It is available with a 70-mL chamber, which is FDA approved for use in patients with a BSA greater than 1.7 m2 The TAH was introduced in 1982 by Robert Jarvik as the Jarvik-7 It has since been known as the Symbion, CardioWest, and is currently the SynCardia TAH In 1985 the Jarvik-7 bridged a patient 9 days to transplant, and an IDE for bridge to transplant was initiated By 1993, CardioWest owned the Jarvik-7, and an IDE study was underway for its use as bridge to transplantation or destination therapy In 2001, SynCardia took over the Jarvik-7, and in 2004, the FDA approved the SynCardia TAH for bridge to transplantation Unfortunately, only 30 drivers, known as “Big Blue” (190 kg), existed worldwide, which limited use of the TAH until 2009, when the much smaller Companion Driver was introduced and quickly followed by the portable Freedom Driver (weighing approximately 6 kg) in 2010 Since the introduction of the Freedom Driver, which can be carried in a backpack, TAH use has tripled, and more than 40% of the more than 1750 implants have been performed in the past 6 years compared with the previous 25 years In pediatrics, the TAH is not meant to replace existing devices in the care of children but help care for those children who do not have a great mechanical support option First, by removing both ventricles and atrioventricular valves, there is no right heart failure, atrioventricular valve regurgitation, cardiac arrhythmias, ventricular clots, intraventricular communications, or low blood flow This, combined with a high CO, makes it ideal for patients with chronic rejection postorthotopic heart transplant (where immunosuppression can be stopped), a late failing Fontan circulation with end-organ dysfunction, chronic right heart failure with LVAD, significant biventricular restrictive disease, a large ventricular clot burden, primary arrhythmia-induced heart failure, cancer, or multiple defects that may require repair prior to VAD placement.37 There is very little known about long-term outcomes in pediatrics for the TAH, but a recent compilation of the world experience of patients aged 21 years or younger reported 43 devices implanted from 2005 to 2015.38 Positive outcomes were reported in 63% of the patients at 90 days, which is similar to the adult TAH experience Because of improving results and the increased use of the TAH in pediatrics and congenital heart patients, the SynCardia 50/50-cc TAH was developed It is currently the subject of a clinical trial for BSAs ranging from 1.2 to 1.85 m2 or those who can be demonstrated to fit by virtual implantation technique, which represents the first time that virtual fit has been accepted as a criterion by the FDA Studies such as those by Moore et al.39 have demonstrated that virtual fit changed the eligibility of 33% of patients and allowed fit down to a BSA of 0.9 m2 This has greatly expanded its use in pediatric patients The ongoing IDE trial of this device presently has eight patients in the primary and secondary arms, with a survival of greater than 80% However, the worldwide experience of 60 patients has demonstrated that the 50/50-mL device has had its desired effect, although numbers remain small, of allowing TAH support to increase in congenital patients (4% to 9%), pediatrics (4% to 13%), and perhaps most significantly in women (12% to 70%) Continuous Flow Ventricular Assist Devices The introduction of CF devices to the pediatric field led to several important changes in device design, not least of which was smaller device sizes, allowing for intracorporeal support in pediatrics The CF devices also came with a lower morbidity profile and less pump thrombosis These advantages, coupled with the ability to go home, led to supporting patients on these devices regardless of whether or not they were listed for transplantation With a CF device in place, patients can be discharged, resume most “normal” life activities, and be evaluated at a later date for potential heart transplant However, only approximately 50% of CF VAD pediatric patients are discharged home Heartmate II Thoratec HeartMate II has a rotary, axial flow pump that can provide CF at 2.5 to 10 L/min Due to its size, the HeartMate II is approved for bridge to transplant or as destination therapy in pediatric patients with a BSA of 1.4 m2 or greater and can be used for discharge home This device has been tried and improved in adult patients, with more than 25,000 implants worldwide Of those, 6451 devices have been in place greater than 3 years, 2513 devices more than 5 years, and 46 for more than 10 years This device has a low incidence of thromboembolic events and excellent outcomes in pediatrics, with greater than 95% of patients either transplanted, recovered, or remaining on the device at 6 months after implant in a review of INTERMACS data.40 The most frequent complication was bleeding (21%), and stroke and sepsis occurred in 7% and 11%, respectively Even in this early series (2008–2011) with only 28 patients followed over 6 months, the results of this study are very encouraging for this device As of 2017, Abbott has acquired Thoratec and with it, the HeartMate 3, which was FDA approved for “short-term hemodynamic support (e.g., bridge to transplant or bridge to myocardial recovery)” in late 2017, although it has been available for short- and long-term use in Europe since 2015.41 The HeartMate 3 uses complete magnetic levitation technology to provide frictionless rotor movement, reducing hemolysis and thrombosis As with former CF devices, we anticipate the HeartMate 3 will begin to see use in select pediatric patients (Video 66.2) HVAD HeartWare HVAD (Medtronic) is an intracorporeal centrifugal LVAD that has allowed for discharge to home in children down to a BSA of 1.0 m2 This device is intracorporeal and is smaller than the HeartMate II, improving device comfort and making it useful in patients with poor healing, such as Duchene muscular dystrophy.18 An early multicenter study from 2015 reported excellent outcomes in 12 patients from around the world who were discharged home with a mean support time of 290 days, while commenting on at-home management.42 Patients ranged from 8 to 15 years of age, and the smallest was an 18-kg child with a BSA of 0.8 m2, although implantation down to a BSA of 0.6 m2 has been reported.43 Eight of the children returned to school Thirty readmissions occurred in 10 patients (0.02 events/person per month) most commonly for driveline infection (22%) No pump thrombosis or neurologic thrombotic episodes occurred At the conclusion of the study, five of the patients had been bridged to transplantation, five were awaiting transplant, one device was explanted after recovery, and the final family elected to remain on the device as destination therapy In an analysis of the global experience with the HeartWare HVAD, Conway et al reported on 205 pediatric patients in 2017.43a Males were more frequently implanted (61%), and cardiomyopathy was the most common diagnosis (82%) More than 50% of patients were discharged home, and this number improved with experience At 1 year, 65% had been transplanted, 21% remained on the ... congenital patients (4% to 9%), pediatrics (4% to 13%), and perhaps most significantly in women (12% to 70%) Continuous Flow Ventricular Assist Devices The introduction of CF devices to the pediatric field led to several important... changed the eligibility of 33% of patients and allowed fit down to a BSA of 0.9 m2 This has greatly expanded its use in pediatric patients The ongoing IDE trial of this device presently has eight patients in the primary and secondary arms,... changes in device design, not least of which was smaller device sizes, allowing for intracorporeal support in pediatrics The CF devices also came with a lower morbidity profile and less pump thrombosis These advantages, coupled with the