Current status of ventricular assist devices in the pediatric population

Sixth Annual Report of the Pedimacs Registry (2012–2021), Evaluating 1,355 Devices in 1,109 Patients Under 19 Years of Age

Ventricular assist devices (VADs) are a crucial therapeutic tool for managing patients with decompensated congestive heart failure. Unlike the adult population, experience in children is limited. However, this has not prevented a “boom” in their utilization over the past two decades. For instance, in 2005, only 10% of heart transplant recipients had a VAD prior to transplantation, whereas this figure is now approximately one-third.

The Pediatric Interagency Registry for Mechanical Support (Pedimacs), under the STS, has recently published its sixth annual report on VAD use in the pediatric population. This report includes data spanning nine years (2012–2021) covering 1,355 devices implanted in 1,109 patients (<19 years) across 42 U.S. hospitals. Key findings are as follows:

Most common indications: cardiomyopathy (58%), congenital heart disease (26%), and myocarditis (9%).
Most popular devices: implantable continuous-flow (40%), paracorporeal pulsatile (28%), and paracorporeal continuous-flow (27%).
Device selection influenced by patient characteristics: Patients supported with paracorporeal continuous-flow VADs tended to be younger, had more complex congenital heart defects, and were in worse clinical condition.
Outcomes at six months: >80% of patients were well, whether transplanted, recovered, or alive with a VAD. For the subgroup with implantable continuous-flow devices, this figure exceeded 90%.

The first two weeks post-implantation presented the highest risk for adverse events, primarily bleeding and neurological complications, which negatively impacted long-term survival.

COMMENTARY:

This report attempts to capture the current landscape of pediatric VAD use, highlighting the challenges of a heterogeneous pediatric population. The registry includes children with congenital heart defects (univentricular physiology accounts for two-thirds of congenital cases), biventricular physiology, primary cardiomyopathies, and acquired heart conditions. Primary diagnosis significantly influences baseline condition, age, type of device implanted, and, consequently, survival outcomes. Added to this is the variability in clinical management, such as timing of VAD indication, particularly in high-risk groups (e.g., single ventricles, cardiogenic shock, restrictive or hypertrophic cardiomyopathies).

When interpreting data from implantable continuous-flow VADs, it is essential to consider that most experience was with the HeartWare device, which was withdrawn by the FDA in 2021. The approval of HeartMate 3 for pediatric use is a recent milestone achieved in December 2020. Positive outcomes associated with these devices are partly attributable to their use in older, less complex, and less critically ill children.

In conclusion, Pedimacs data cannot be entirely extrapolated to other contexts due to inherent biases in a voluntary registry and significant differences between healthcare systems in the U.S. and Spain. However, Pedimacs does illustrate the growing trend of VAD use in the pediatric population—a trend that is already being observed in our country.

REFERENCE:

Adachi I, Peng DM, Hollander SA, Simpson KE, Davies RR, Jacobs JP, et al; Pedimacs Investigators. Sixth Annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report: The Society Of Thoracic Surgeons Pedimacs Annual Report. Ann Thorac Surg. 2022 Nov 17:S0003-4975(22)01433-3. doi: 10.1016/j.athoracsur.2022.10.042.