Understanding the Pediatric Ventricular Assist Device W. James Parks, MSc., MD Pediatric Cardiologist Assistant Professor of Pediatrics and Radiology Children s Healthcare of Atlanta Sibley Heart Center Cardiology Emory University School of Medicine
Understanding the Pediatric Ventricular Assist Device Introduction: Mechanical devices used to support in part or in total, the circulatory hemodynamics required to maintain or sustain the function of the failing or compromised heart. Heart transplantation is today is an increasingly common treatment for end-stage heart failure in all ages. However, many candidates expire or are rendered non-candidates due to the ravages of low cardiac output upon the body. Background: In patients, with severe heart failure prolonged periods of myocardial unloading and support through the use of Ventricular Assist devices has been shown to be critical in providing occasion for full functional recovery or sustainable improvement. Support through the use of these devices can increase the output of present myocardial effort and inotrophic therapy. These devices can provide life sustaining output and thus, critically needed time for recovery ( bridge to recovery ), analysis or donor ( bridge to transplant ) procurement. In those not
considered candidates for additional surgery, it provides destination therapy. Intra-Aortic Balloon Pump: A counterpulsation balloon synchronized to the EKG or arterial waveforms. It reduces myocardial work through afterload reduction and improves myocardial oxygen by augmentation of diastolic blood pressure and coronary perfusion pressure. Extracorporeal Membrane Oxygenation (ECMO): ECMO remains the most often applied mechanical support for infants and young children. Its problems related to anticoagulation and patient bleeding, hematologic factor consumption, cannula and filter thrombosis (dessiminated intravascular coagulation), and time limitations restrict its use after only a few days or weeks. However, now several continuous flow and pulsatile extracorporeal and implantable assist devices are available for pediatric use. These devices were developed specifically for pediatric patients with miniaturized pumps and cannulas suitable for all pediatric patients including neonates. Continuous-Flow Left Ventricular Assist Device A Pulsatile-Flow Left Ventricular Assist Device
Slaughter et al., Advanced Heart Failure Treated with Continuous-Flow LVAD NEJM 361:23 Dec 3, 2009 I. Etiologies of Cardiac Failure: Indications for VAD A. Cardiomyopathy (congenital or acquired) B. Active myocarditis (infections) C. Anomalous coronary arteries with severe nonrecoverable myocardial impairment D. Post surgical heart failure (non-recoverable) E. Congenital Heart Disease (10%, reportedly uncorrectable) F. Toxins G. Tumors H. etc.,
II. Ventricular Assist Devices (LVAD/RVAD/BiVAD): The LVAD is used most commonly used ventricular support device however, if pulmonary arterial resistance is high, right ventricular assistance (RVAD) becomes necessary. The used of Bi-ventricular (BiVAD) support is rarely necessary but is being used increasingly for long-term support if needed in the Pediatric patient. III. Needs / Requirements for success: Team Approach IV. Reported Complications / Limitations: A. Bleeding B. Infection C. C. Thrombo-embolic events D. Right Heart Failure E. Device Failure F. Immunologic Effects and Allosensitization G. Defects in cellular immunity H. B-cell activation V. Device Types and Reported Improvements: A. Medtronic Biomedicus VAD: A ventricular assist device (VAD) for pediatric patients less than five years of age. It is a short-term use nonpulsatile, centrifugal-flow system. It can support patients aged, five to sixteen years. B. The MicroMed DeBakey (VAD) Child: A long-term, non-pulsatile, axial flow ventricular assist system. It is the first FDA approved device for use in children.
C. The Berlin Heart: A long-term pulsatile ventricular assist device (VAD), which can provide support of the left or right ventricle (LVAD/RVAD) or serve as a biventricular device (BiVAD) in heart conditions that can no longer be managed with medication therapy. This system is available in four pump sizes for use infants and adult-sized patients. The Berlin Heart has not received FDA approval, however its use has been allowed on a case-by-case basis as it is one of the only proven long-term assist devices available for use in infants and small children. D. Thoratec paracorporeal VAD: Is used in adult-size patients for longterm, pulsatile-ventricular assistance. It is a versatile system which can also provide left, right or biventricular support to adult-sized patients. This longterm device enables patient mobility and performance of many routine activities as a bridge to recovery or transplantation. E. Impella PERCUTANEOUS Left VAD: Is used in post cardiotomy shock. It is smaller with low cost and easy to place without a teans-septal puncture. F. Newer-generations and future: Magnetic levitation technology with advanced energy system and smaller control consoles. Incor Left VAD: accentuated axial flow pump. Heartmate III: magnetically suspended centrifugal pump VI. Contraindications:
VII. Device Components: VIII. Surgical Techniques: IX. Clinical Results: X. Summary: