Heartmate II Inflow Cannula Position on Chest X-Ray Predicts Inotrope Dependence

Abstract

<h3>Purpose</h3> We hypothesized that LVAD inflow cannula malposition contributes to numerous negative outcomes after device implantation. We further hypothesized that inflow cannula malposition may be determined by early post-operative CXR. <h3>Methods and Materials</h3> We reviewed CXR from 79 consecutive Heartmate II implantations (bridge to transplant or destination therapy). We measured LVAD inflow cannula position relative to the sternum on 1st upright PA and Lateral chest x-ray. [figure 1] We evaluated the following explanatory variables: age, LV diameter, redo sternotomy, BMI, cannula angle relative to sternum on PA CXR, cannula angle relative to sternum on Lateral CXR. We used multivariate logistic regression to evaluate the following implantation complications: TIA, stroke, post-implantation inotrope dependence, hemolysis, thrombosis, new ventricular tachycardia, and death. <h3>Results</h3> Cannula angle on PA CXR is associated with inotrope dependence (OR 1.12, p=0.001). All patients (n=16) with cannula angles outside of the range of 4° to 54° on PA CXR or -45° to 59° on lateral CXR experienced at least one of the studied complications. Additionally, increased BMI is associated with inotrope dependence (OR 1.14, p=0.045) and death (OR 1.13, p=0.049). Redo sternotomy is associated with new onset ventricular tachycardia (OR 5.97, p=0.03). LV diameter is associated with hemolysis (OR 0.27, p=0.043). <h3>Conclusions</h3> All patients with extreme inflow cannula angles experienced at least one major complication. Across all ranges, inflow cannula angulation on PA CXR predicted inotrope dependence. Secondary variables including BMI, redo sternotomy, and small LV were associated with major complications. Technical aspects of LVAD implantation remain paramount in assuring optimum outcomes.