Highlights
The EXCOR Active Driver, a new driving system for the Berlin Heart EXCOR Pediatric ventricular assist device, showed no major device malfunctions across both the investigational device exemption cohort and the continued access cohort.
Among the 40 prospectively enrolled investigational device exemption patients, 90-day mortality was 0%, with most patients either remaining successfully supported or proceeding to transplantation, recovery, or another support strategy.
In the larger continued access population of 118 additional children, survival at 90 days was 98.1%, reinforcing the reliability of the platform in routine real-world use.
The study also offers an important regulatory proof of concept: pediatric class III device evaluation can be conducted using prospective registry-linked infrastructure, potentially reducing cost and improving feasibility in rare, high-risk populations.
Background and Unmet Clinical Need
Mechanical circulatory support in children remains one of the most technically and logistically challenging areas in cardiovascular medicine. Pediatric patients with advanced heart failure, especially infants and small children who are too small for implantable continuous-flow devices designed for adults, often depend on paracorporeal pulsatile systems as a bridge to transplantation or, less commonly, myocardial recovery. In the United States and many other settings, the Berlin Heart EXCOR Pediatric has been the principal durable ventricular assist device option specifically available for this purpose.
Its clinical importance is well established. The EXCOR platform expanded survival opportunities for children who previously had few realistic bridging options. However, the system’s traditional external driver, the IKUS, has meaningful practical limitations. Large external hardware, reduced portability, and constrained battery-supported mobility can materially affect developmental activity, rehabilitation, family interaction, and overall quality of life during prolonged support. These concerns are particularly relevant in pediatrics, where device support is not merely a technical bridge but also a lived experience for the child and caregivers.
The EXCOR Active Driver was developed to address these gaps. The new system is intended to improve mobility, extend battery-supported operation, and permit greater physiological adaptability while maintaining the core safety requirements expected of a life-sustaining class III device. For clinicians, the central question is straightforward: can mobility and usability be improved without compromising reliability, hemodynamic support, or patient safety? The present prospective multicenter evaluation directly addresses that question.
Study Design
Overall design and regulatory framework
This was a prospective, multicenter clinical trial performed under a U.S. Food and Drug Administration-approved investigational device exemption, followed by a continued access protocol. The design is notable not only for evaluating the device itself, but also for testing a pragmatic regulatory model that leverages clinical registry infrastructure for data capture and oversight in a rare pediatric population.
Study population
Forty children were enrolled in the investigational device exemption cohort. Their mean age was 38.2 months, underscoring that many were infants or very young children. Congenital heart disease was present in 55% of this group, confirming that the study population reflected a clinically complex pediatric heart failure population rather than a narrowly selected cardiomyopathy-only cohort.
After initial enrollment, 118 additional patients were treated under a continued access protocol. Taken together, these cohorts provide both a tightly adjudicated prospective trial dataset and a broader real-world experience.
Intervention
All patients received support using the Berlin Heart EXCOR Pediatric ventricular assist device driven by the EXCOR Active Driver. The study did not compare the Active Driver against a randomized control device or against the legacy IKUS driver. Instead, its focus was performance, safety, and clinical outcomes in a prospective multicenter setting.
Endpoints and adjudication
Primary endpoints included major device malfunction, adverse events, and successful outcomes at 90 days postimplantation. Successful outcomes were defined pragmatically as survival to transplantation, recovery explant, or continued support at 90 days. This endpoint structure is clinically appropriate in pediatric VAD research, where transplantation timing is highly dependent on donor availability and where “alive and supported” is often a meaningful therapeutic success.
Adverse events were adjudicated by an independent Clinical Events Committee, and a Data Safety Monitoring Board provided oversight. Such safeguards are particularly important in device studies where event definitions, causality assessment, and attribution can otherwise vary substantially across centers.
Outcomes were summarized using descriptive statistics and competing risk models. The use of competing risk methodology is methodologically sound in this context because transplantation, recovery, death, device conversion, and continued support are mutually informative, clinically relevant events that cannot be adequately represented by a single Kaplan-Meier survival estimate alone.
Key Results
Device reliability
The most striking finding was the complete absence of major device malfunctions. No episodes of major malfunction occurred in the 40-patient investigational device exemption cohort, and no major malfunctions were reported in the 118-patient continued access cohort either. For a pediatric life-sustaining device intended to improve mobility and usability, this is a highly consequential result. Any redesign that increases portability could theoretically introduce new failure modes involving power, alarms, tubing interfaces, or pneumatic performance. The observed absence of major malfunction therefore supports the engineering robustness of the Active Driver in clinical practice.
That said, absence of major malfunction should not be interpreted as absence of all technical or operational issues. The abstract specifically reports major device malfunction rather than all minor technical events, troubleshooting episodes, or user-interface concerns. Nevertheless, for regulatory and bedside decision-making, the primary signal is reassuring: the device did not demonstrate catastrophic reliability concerns in either cohort.
Clinical outcomes in the investigational device exemption cohort
Among the 40 investigational device exemption patients, 65% remained on support at 90 days. An additional 17.5% had undergone heart transplantation by that time point, and 1 patient was explanted for recovery. Another 15.0% were converted to another support modality. Importantly, 90-day mortality was 0%.
These outcome distributions reflect the realities of contemporary pediatric advanced heart failure care. Continued support at 90 days is not a failure; in many children, prolonged support is expected while awaiting donor organs or while determining whether an alternative mechanical support strategy is preferable. Similarly, conversion to another support modality may represent escalation or adaptation rather than treatment collapse. In this light, the 0% 90-day mortality in the IDE cohort is particularly encouraging.
Stroke incidence in the IDE cohort was 12.5%. This figure requires careful interpretation. Neurologic events remain one of the most feared complications of pediatric VAD support, and the Berlin Heart experience historically has shown that thromboembolic and hemorrhagic neurologic injury remain major determinants of morbidity. A 12.5% stroke rate is not trivial and underscores that improved driver mobility does not eliminate the intrinsic hemocompatibility and anticoagulation challenges associated with pediatric pulsatile support. Still, the rate should be considered in the context of the severe baseline illness of the cohort and historical pediatric VAD experience.
Clinical outcomes in the continued access cohort
The continued access protocol enrolled 118 additional patients and serves as an important test of generalizability. At the time of data abstraction, 37% had undergone transplantation, 31% were alive on device, 6% had the device explanted for recovery, and 23% had been converted to another support modality. Support was withdrawn in 3 patients. Survival at 90 days was 98.1%.
This larger cohort broadly confirms the findings seen in the IDE group. High short-term survival, durable support through transplantation or recovery, and freedom from major device malfunction together suggest that the Active Driver performs reliably not only under formal trial conditions but also in expanded clinical use.
The relatively large proportion of patients converted to another support modality in both cohorts deserves attention. The abstract does not provide granular reasons for conversion. Potential explanations may include patient growth, evolving hemodynamic requirements, need for different ventricular support configuration, or transition to alternative temporary or durable systems. Without detailed indication-level data, conversion should be interpreted cautiously and not automatically categorized as treatment failure.
Safety interpretation
The overall safety signal appears favorable, but not complication-free. The absence of major malfunction and high 90-day survival are strong positives. However, stroke remains clinically important, and the abstract does not provide a full breakdown of bleeding, infection, pump thrombosis, hemolysis, or right heart failure-related complications. Because these adverse events frequently shape the daily burden of pediatric VAD care, full-text review will be necessary for a comprehensive safety comparison with prior EXCOR experience.
Clinical Interpretation
For pediatric heart failure teams, the practical value of the EXCOR Active Driver lies in its potential to improve life during support without sacrificing safety. Mobility matters. It affects physical therapy participation, pulmonary conditioning, developmental stimulation, and family-centered care. A more portable and adaptive driver may also facilitate smoother inpatient workflows and could possibly broaden the circumstances in which patients can engage in rehabilitation or lower-acuity care environments.
These benefits, however, should be understood as adjunctive rather than transformative. The Active Driver does not solve the core biological problems of pediatric mechanical support: thrombosis risk, bleeding risk under anticoagulation, infection vulnerability, and the scarcity of donor hearts. It is best viewed as an important systems-level innovation within an established support platform.
The high proportion of children with congenital heart disease is another notable strength. This subgroup is often underrepresented or difficult to study because anatomy, surgical history, and physiology are highly heterogeneous. Demonstration of reliable performance in such a population enhances confidence that the findings are applicable to the real-world pediatric advanced heart failure population seen at tertiary centers.
Methodological Strengths
Several aspects of the study strengthen its credibility. First, the design was prospective and multicenter, limiting some of the biases associated with single-center retrospective series. Second, adverse event adjudication by an independent Clinical Events Committee improves consistency and reduces site-level subjectivity. Third, Data Safety Monitoring Board oversight is essential for a life-sustaining class III device study. Fourth, the inclusion of a continued access cohort expands external validity and provides insight into performance beyond the initial investigational sample.
The study’s use of registry-enabled infrastructure is also highly important from a policy and regulatory standpoint. Pediatric device development is often hampered by small patient numbers, ethical barriers to randomization, center-level expertise concentration, and high trial costs. A rigorous prospective registry framework may offer a more feasible pathway for post-approval evidence generation and even selected premarket evaluations, provided data definitions, event adjudication, and follow-up completeness remain strong.
Limitations and Remaining Questions
The study also has important limitations. Most obviously, there was no randomized comparator. As a result, one cannot definitively conclude that the Active Driver improves outcomes relative to the prior IKUS driver. The current data show safety and feasibility, not comparative superiority.
Second, the abstract provides limited detail on secondary adverse events and functional outcomes. Because the Active Driver is intended in part to improve mobility and quality of life, the absence of reported patient-centered measures such as rehabilitation participation, caregiver burden, activity tolerance, or discharge disposition limits interpretation of its full clinical value.
Third, follow-up emphasis is on 90-day outcomes. While this is a common and clinically useful milestone in VAD studies, longer-term support outcomes are particularly relevant in pediatrics, where waiting times can be prolonged and cumulative adverse-event burden may increase over time.
Fourth, the conversion-to-other-support category remains somewhat ambiguous without more context. Future reporting should clarify the reasons for conversion, timing relative to implantation, and whether such transitions were elective, rescue-based, or strategy-driven.
Finally, generalizability outside experienced pediatric mechanical support centers remains uncertain. Device performance in specialized institutions may not fully predict outcomes in lower-volume settings, especially when anticoagulation management and neurologic monitoring practices vary.
Implications for Practice and Policy
Despite these limitations, the findings are clinically meaningful. For transplant and heart failure programs caring for infants and small children, the EXCOR Active Driver appears to offer a more modern support interface without an evident penalty in major safety outcomes. If full-text data confirm improved usability and mobility, the device may become an important incremental advance in pediatric bridge-to-transplant care.
Equally significant is the regulatory implication. Rare pediatric conditions often cannot support large conventional trials. The successful use of a prospective multicenter registry-linked framework for a class III device suggests a scalable model for future pediatric cardiovascular technologies. This approach could be especially valuable in congenital heart disease, pediatric electrophysiology, and small-population implantable or external support systems, where innovation has historically lagged behind adult care.
For clinicians, the study reinforces a broader lesson: pediatric device innovation should be assessed not only by survival, but also by reliability, developmental impact, rehabilitation potential, and caregiver experience. In that respect, the Active Driver addresses a genuine unmet need.
Conclusion
The prospective multicenter evaluation of the EXCOR Active Driver provides strong early evidence that improved mobility and modernized driver functionality can be achieved in pediatric ventricular assist support without sacrificing core device reliability. Across both the investigational and continued access cohorts, no major device malfunctions were observed, and 90-day survival was excellent. These findings support the Active Driver as a credible advancement for children requiring durable paracorporeal support as a bridge to transplantation, recovery, or further strategy refinement.
At the same time, the study does not eliminate the persistent clinical challenges of pediatric VAD care, particularly stroke and other support-related complications. Its greatest contribution may therefore be twofold: a safer and more practical support ecosystem for children, and a validated framework for evaluating future pediatric high-risk devices in a rare-disease setting.
Funding and ClinicalTrials.gov
The abstract states that the study was conducted under a U.S. Food and Drug Administration-approved investigational device exemption with subsequent continued access protocol. Specific funding details are not provided in the supplied abstract. A ClinicalTrials.gov registration number is not included in the provided citation or abstract summary and therefore cannot be verified here.
References
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