Fig. 4.

PDF Results at ROI regions—PDF results obtained from the flow straightener ROI populated a similar low SA range in both VADs, and similar tail region distributions were found. The PDF results from the rear hub ROI populated a similar low SA range between two VADs; however, higher probability density (thrombogenic potential) was found at the HMII tail region comparing to the distribution of the HA5 tail region. Very different PDF distributions between the HMII and HA5 were found at the impeller-shroud gap ROI; the main mode of the HA5 is left-shifted (toward lower SA range) compared to the HMII, and higher distribution at the HMII tail region (riskier high SA range) comparing to the HA5. PDF results from the impeller blade ROI indicated that the main modes of both VADs populated a similar low SA range; however, the tail region of HMII's PDF showed higher density at higher SA range than the HA5. The PDF results from the front hub ROI showed that the main mode of HMII was right-shifted (toward higher SA range) comparing to HA5's main mode, and an additional mode was observed at the tail region of HMII comparing to HA5. The PDF result from the diffuser ROI indicated the main mode of HA5 was right-shifted compared to HMII, but very similar distribution was found at the tail region of both VADs.