Utility of cardiac computed tomography for inflow cannula patency assessment and prediction of clinical outcome in patients with the HeartMate II left ventricular assist device.

Abstract

Proper inflow cannula orientation during implantation of the HeartMate II (HMII) left ventricular assist device (LVAD) is important for optimal pump function. This article describes our experience with cardiac computed tomography (CCT) to evaluate inflow cannula patency and predict future adverse outcomes (AE) after HMII LVAD implantation. Ninety-three patients underwent HMII LVAD implantation for end-stage cardiomyopathy from January 2010 until March 2014. A total of 25 consecutive patients had CCT after the implantation; 3 patients were excluded from the analysis due to associated abnormality of the outflow graft. The 22 patients with CCT after HMII LVAD were censored for adverse events related to LVAD malfunction after HMII LVAD implantation. The maximum percentage of inflow cannula obstruction on CCT was recorded. We analysed the predictive value of CCT in addition to other clinical and diagnostic variables for future AEs. Seven of the 22 patients (32%) experienced AEs after HMII LVAD implantation. The degree of inflow cannula obstruction was higher in the group of patients who experienced an AE (70 vs 14%; P < 0.001). Inflow cannula obstruction >30% showed excellent correlation with AE longitudinally based on receiver operating curve (0.829). The group with AEs more frequently experienced CHF symptoms (P = 0.054). Inflow cannula obstruction >30% on CCT predicts future adverse events in patients with HMII LVAD; the need for surgical intervention in terms of LVAD exchange or urgent listing for heart transplantation should be considered in good surgical risk patients. Cardiac computed tomography should be considered routinely postoperatively in patients with HMII LVAD.