Abstract
Introduction: Implantation of a left ventricular assist device (LVAD) has been shown to reverse cardiac remodeling through a distinct pattern of gene expression. We sought to determine if the differences in flow rendered by an axial flow pump would produce a distinct transcriptome when compared with a pulsatile device.
Methods: RNA was isolated from paired myocardial tissues taken from the left ventricular apex of LVAD recipients at the time of device insertion and again at transplantation. Three of the patients who were studied underwent implantation of an axial flow pump (Micromed DeBakey VAD) while three patients received a pulsatile device (Heartmate). Double-stranded cDNA was synthesized from total RNA and hybridized to the Affymetrix Human U133 Plus 2.0 Array chip. Normalization and expression value summarization were performed using robust multi-chip average. The local pooled error method was used to determine differential expression.
Results: A total of 2332 genes were found to undergo statistically significant change following LVAD support with an axial flow pump. Of these, 62 genes were found to be significantly changed in the pulsatile device group while 2270 genes were found to be expressed in the axial flow group alone.
Conclusions: These findings suggest that differences in pulsatility during LVAD support induce distinct changes in gene expression. Additional studies are needed to correlate these results with alterations in function.