A Single-Institutional Experience with 36 Children Smaller Than 5 Kilograms Supported with the Berlin Heart Ventricular Assist Device (VAD) over 12 Years: Comparison of Patients with Biventricular versus Functionally Univentricular Circulation

Abstract

Objectives We reviewed outcomes in all 36 consecutive children <5 kg supported with the Berlin Heart pulsatile ventricular assist device (VAD) at the University of Florida, comparing those with univentricular circulation (n  =  23) to those with biventricular circulation (n  =  13). Methods The primary outcome was mortality. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival after VAD insertion. T-tests using estimated survival proportions and standard errors were used to compare groups at specific time points. Results Of all 82 patients ever supported with Berlin Heart at our institution, 49 (49/82  =  59.76%) weighed <10 kg and 36 (36/82  =  43.90%) weighed <5 kg. Of these 36 patients who weighed <5 kg, 26 (26/36  =  72.22%) were successfully bridged to transplantation. Of these 36 patients who weighed <5 kg, 13 (13/36  =  36.1%) had biventricular circulation and were supported with 12 biventricular assist devices (BiVADs) and 1 left ventricular assist device (LVAD) (Age [days]: median  =  67, range  =  17–212; Weight [kilograms]: median  =  4.1, range  =  3.1–4.9), while 23 (23/36  =  63.9%) had univentricular circulation and were supported with 23 single ventricle-ventricular assist devices (sVADs) (Age [days]: median  =  25, range  =  4–215; Weight [kilograms]: median  =  3.4, range  =  2.4–4.9). Of 13 biventricular patients who weighed <5 kg, 12 (12/23  =  92.3%) were successfully bridged to cardiac transplantation. Of 23 functionally univentricular patients who weighed <5 kg, 14 (14/23  =  60.87%) were successfully bridged to cardiac transplantation. For all 36 patients who weighed <5 kg: 1-year survival estimate after VAD insertion  =  62.7% (95% confidence interval [CI]  =  48.5%-81.2%) and 5-year survival estimate after VAD insertion  =  58.5% (95% CI  =  43.8%-78.3%). One-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 49.7% (95% CI  =  32.3%-76.4%) in univentricular patients, P  =  0.018. Three-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 41.4% (95% CI  =  23.6%-72.5%) in univentricular patients, P  =  0.005. Conclusion Pulsatile VAD facilitates bridge to transplantation in neonates and infants weighing <5 kg; however, survival after VAD insertion in these small patients is less in those with univentricular circulation in comparison to those with biventricular circulation.