Bridge to recovery with Berlin Heart EXCOR in children <10 kg with dilated cardiomyopathy: a histological analysis

Objectives: This study aimed to identify the histological characteristics associated with bridge to recovery using Berlin Heart EXCOR® (BHE) in paediatric patients <10 kg with dilated cardiomyopathy.

Methods: Of the 10 consecutive patients <10 kg with dilated cardiomyopathy who underwent BHE implantation between 2013 and 2018, 4 patients showed improvement in left ventricular (LV) function, resulting in successful BHE explantation (recovery group). The remaining 6 patients showed persistent LV dysfunction and underwent heart transplantation (non-recovery group). The following variables were compared between the 2 groups: (i) histological findings in LV myocardium obtained at BHE implantation and (ii) LV function after BHE implantation assessed with echocardiography and cardiac catheterization.

Results: The degree of myocardial fibrosis was significantly lower, and the capillary vascular density was significantly higher in the recovery group than in the non-recovery group [16% (standard deviation 5.9%) vs 28% (5.9%), P = 0.021, and 65 (11) vs 43 (18) units/high-power field, P = 0.037, respectively]. The changes during 3 months after BHE implantation in LV diastolic dimension (z-score) and ejection fraction were significantly greater in the recovery group than in the non-recovery group [-9.6 (3.5) vs -3.6 (4.5), P = 0.045, and 36% (13%) vs 13% (13%), P = 0.032, respectively].

Conclusions: In paediatric patients <10 kg with dilated cardiomyopathy, bridge to recovery with BHE implantation was achieved in patients with less injured LV myocardial histology at BHE implantation.