Pediatric heart support with a newly developed catheter based pulsatile 12F rotary blood pump: an animal study.

Background: To evaluate mechanical and hematological compatibility of a pediatric, temporary left heart support system in a lamb model as a less traumatic alternative to the widely used ECMO.

Methods: A small, pulsatile rotary blood pump (target flow 0.5l/m at 80 mm Hg pressure head at 120 pulses per min) was inserted in six lambs (15.1+/-1 kg) via a left thoracotomy, through a purse string in the arcus aortae. With fluoroscopy the tip (=inflow) of the catheter was positioned in the outflow tract of the left ventricle. The outflow part was positioned immediately above the aortic valve. Animals were extubated at the end of the procedure. Mechanical and hematological parameters were followed for 14 days.

Results: Five animals survived a 2-week follow-up. One animal died because of empyema on day 6. Flow maintained stable (0.8+/-0.2l/m) in all animals during the evaluation period. Free hemoglobin as a parameter of hemolysis and hematocrit remained also stable. Necropsy revealed minimal fibrous reaction on one aortic valve leaflet in one animal and small hematoma formation in three. All animals showed mild signs of endothelial damage on the aortic arch at the level of the motor housing. One animal showed signs of old kidney infarction suggesting possible embolization during placement.

Conclusion: This newly developed, catheter based, pediatric heart support system generates a stable flow for 14 days without compromising hematological stability and with acceptable tissue damage due to positioning of the catheter.