Association of Outflow Cannula Angulation with Adverse Neurological Events in Patients with CF-LVAD

Abstract

<h3>Purpose</h3> Adverse neurological outcomes are the Achilles heel of the current day LVAD technology and are associated with worse survival. Our previous data suggests that outflow cannula (OFC) angles measured using cardiac CT may correlate with stroke in continuous-flow HeartMate II patients. Therefore, the aim of our study was to assess the relationship of inflow cannula (IFC) and outflow cannula (OFC) position with neurological outcomes centrifugal flow pumps (HM3 and HVAD). <h3>Methods</h3> 108 patients underwent LVAD implantation between 2015 and 2019 at our institution. Of these, 68 patients underwent cardiac CT, and 6 were excluded due to poor image quality. Of these patients, a total of 32 neurological events (NE) occurred in 20 patients. These cases were compared to patients with CT data who did not have NEs. 2D angle measurements were performed on positions of OFC relative to the ascending aorta and IFC relative to the mitral valve. Further we used a novel point-based 3D measurement system to determine the angles in an x-y-z plane. Baseline demographic data and outcome data were collected for all patients. Optimal cut-point of the OFC angle was determined using ROC curve analysis. <h3>Results</h3> Of the 62 patients recruited for this study, 65% had HM3 and 35% had HVAD. The median OFC angle on 2D in patients with NE was 59.8 degrees relative to the aorta, compared with a median angle of 51.7 degrees in patients without NE (p=0.02). Similarly on 3D angle measurements, a median OFC angle of 86.7 degree was observed in patients with NE, compared to a median angle of 77.4 degrees in patients without NE (p=0.01). IFC angle was not associated with an increased risk of NE. The ROC curve analysis showed optimal OFC angle was < 53 degrees in 2D measurements, with sensitivity of 79% and specificity of 61% at predicting NEs. In 3D measurements the optimal OFC angle was less than < 83 degrees with a sensitivity of 79% and a specificity of 61% at predicting NEs. <h3>Conclusion</h3> Optimal angulation of the outflow cannula in LVAD patients can lead to decreased risk for HRAE. Using cardiac CT chest imaging for 2D and 3D measurements, an optimal outflow cannula angulation of < 53 degrees and < 83 degrees, respectively, should be preferred to minimize the risk for HRAE in patients with centrifugal flow LVAD support.