Assessment of the LVAD Inflow Cannula Position by Cardiac CT

Position of the inflow cannula (IC) within the left ventricle may affect optimal function of the LVAD and contribute to the risk of complications. We evaluated the intraventricular position of the IC in Heartmate II (HM2) and Heartware (HW) LVADs. A single-center retrospective review of the most recent cardiac CT (CCT) of all continuous flow LVAD implants between 10/2006 and 9/2013 was performed. CT acquisitions were completed on a 64 or 256 slice platform using ECG gated helical technique. Measurements were performed in standard 2-chamber and short-axis views. Fisher’s exact and Wilcoxon-Mann-Whitney tests were used to determine statistical difference between groups. A total of 195 patients underwent LVAD implants (101 HM2, 94 HW). At least one CCT was performed on 63 patients. Mean LV end diastolic diameter was 63 ± 11 mm. Apical tip of the IC was more frequently in contact with anterior wall in the HM2 patients (15/24, 62%) compared to HW pumps (5/38, 13%, p<0.001). Basal tip did not abut the anterior wall in any patient. Septal wall contact was 25% vs. 5 % (p=0.05) and lateral wall contact was 29% vs. 25% (p=0.7) in HM2 and HW pumps, respectively. In the total population, the IC was angulated towards the mitral annulus plane (median 33 degrees, IQR 22, 46) and formed a 77-degree horizontal angle in the short axis (IQR 57, 95, figure 1). Angle of the IC was significantly different between HM2 and HW LVADs (table 1). Significant variation exists among patients and between two different types of continuous-flow LVAD with regards to intraventricular position of the inflow cannula. Clinical significance of these variations remains to be determined.