Relationship of IFC Position to Preoperative Anatomy
Table S1 (see Supplemental Material) presents univariate linear regression results for the association between preoperative anatomy and IFC position, while Figure 4 depicts the significant relationships. There was a negative relationship between LVOT angle and anterior-plane IFC angle (beta = -0.534; p = 0.01), indicating a steeper LVOT angle was associated with an inferiorly-directed IFC. Conversely, there was a positive relationship between LVOT angle and lateral-plane IFC angle (beta = 0.517, p = 0.04), indicating a propensity toward laterally-directed IFCs with a more steeply tilted LVOT-apex axis. There was also a significant negative relationship between apex-midline distance and lateral plane IFC angle (beta = -0.204, p=0.04), indicating that a more medial apex predicted lateral-wall malposition, while a laterally displaced apex was associated with a septally-oriented IFC. No anatomic variable predicted total malposition magnitude, and neither LVEDD nor BMI predicted any IFC malposition measure.
Figure 5 depicts the influence of anatomy on IFC position. The pre-LVAD CT demonstrates a more steeply inclined apex-LVOT axis (A: 35.2 degrees; median 32 degrees), while the post-LVAD CTA demonstrates IFC deviation in the inferior (B: -30.6 degrees) and lateral (C: +16.9 degrees) directions as predicted by the regression model.