Use of Zirconia ceramic in the DexAide right ventricular assist device blood journal bearing

Objective: To evaluate the effects of replacing the titanium (Ti)stator housing in the DexAide right ventricular assist device with one fabricated from biocompatible Zirconia oxide(Zr)ceramic.

Methods: Pump hydraulic performance,journal bearing reliability,biocompatibility,and motor efficiency of the Zr stator were evaluated in vitro and in vivo (4 chronic bovine experiments) and compared with those using the Ti stator.

Results: Compared with the Ti stator,the Zr stator showed increased battery life by 38% from 8 hours and 55 minutes on fully charged batteries at 2,500 rpm and 5.0 L/min to 12 hours and 20 minutes.In vitro hydraulic performance was unchanged with the exception of a 20% decrease in power consumption when using the Zr stator. Average in vivo pump flows and speeds using a Zr stator were comparable to the average values for 14 prior Ti stator in vivo studies with the exception of a 19% reduction in power consumption.Hemolysis and platelet aggregation tests were comparable for both stator types.Post explant evaluation of the Zr blood journal bearing surfaces showed no biologic deposition or signs of wear indicating favorable biocompatibility.

	Pump Speed (rpm)	Pump Flow (L/min)	Motor Power (watts)
Titanium Stator (Average of 14 Experiments)	2,539±88	6.0±1.9	3.2±0.2
Zirconia Stator (Experiment #1)	2,504±70	5.2±0.4	2.6±0.2
Zirconia Stator (Experiment #2)	2,499±99	5.9±0.4	2.6±0.2
Zirconia Stator (Experiment #3)	2,367±129	4.7±0.9	2.3±0.3
Zirconia Stator (Experiment #4)	2,098±138	4.1±0.	1.8±0.2

Fig. 1: In vivo pump speed, flow, and power correlations

Conclusions: The results of these studies showed that Zr ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.