Purpose: Pediatric patients with end-stage heart failure frequently require mechanical cardiac support while awaiting heart transplantation. The recent availability and increasing use of the Berlin Heart EXCOR¨ Pediatric Ventricular Assist Device (EXCOR¨ Pediatric) – a miniaturized VAD that can be implanted in infants and young children has increasingly replaced earlier strategies of using ECMO for providing long-term cardiac support in children. Cerebrovascular events (CVEs) represent a significant cause of morbidity for children supported with the EXCOR VAD. Given the incidence of CVEs associated with this device, we sought to describe the time of the cerebrovascular events in children on the EXCOR VAD support at our institution with the aim of finding ways to reduce the risk of their occurrence.
Methods: We collected clinically pertinent data on 37 consecutive patients who underwent Berlin EXCOR VAD implantation from April 15, 2005 through September 9, 2011. Frequency of CVEÕs was described overall, in risk per implantation, risk per day, and in reference to the time of routine institution of anticoagulation therapy (at 48 hours post implantation). Linear regression was used to describe overall risk of stroke rate as a function of time. The frequency of CVEs between the two time intervals was analyzed with FisherÕs exact test.
Results: Over the initial 37 Berlin EXCOR VAD implantations, 12 patients have suffered from 14 cerebrovascular events. Incidence of CVEs decreased with institutional experience, as seen in Figure 1 (p=0.04, R2= 0.6768). Four strokes occurred in the initial 48 hours following implantation, while 10 strokes occurred after the first 48 hours. One stroke was noted after explants of the EXCOR device. Stroke occurred more frequently during the initial 48 hours (5.6%/day) compared to times outside the initial window (0.7%/day), (p = 0.0032).
Conclusions: Cerebrovascular event risk is highest in the initial 48 hours of implantation during the inflammatory period following bypass and prior to the institution of therapeutic anticoagulation. Based on our results overall daily risk for stroke on ventricular assist device improved with institutional experience. Further study is warranted into the collective experience in pediatric patients on the Berlin EXCOR ventricular assist device and the feasibility of early introduction of anticoagulation to describe, contribute to the understanding, and decrease future CVEs.