LVAD Outflow Cannula Position Linked with Higher Stroke Risk

Correct positioning of the outflow cannula for a left ventricular assist device (LVAD) is important, as improper position can lead to an increased risk of stroke, according to new research.

The study, presented at the Heart Failure Society of America Scientific Meeting in Philadelphia, and published in the meeting supplement of the Journal of Cardiac Failure, hypothesized that the way in which varying implant techniques for LVAD inflow and outflow cannula can affect subsequent stroke incidence.

“Stroke remains a major cause of morbidity and mortality in patients with left ventricular assist devices (LVAD),” the researchers wrote. “Although several studies have delineated clinical risk factors for development of stroke, it is not entirely clear whether changes in position/orientation of the LVAD cannula impact incidence of subsequent stroke.”

For their retrospective study, the researchers reviewed all patients who underwent LVAD implantation between 2011 and 2016 in a single center. Baseline demographic information and clinical parameters were ascertained from all patients, as well as inflow and outflow positions assessed by various multidetector cardiac compute tomography parameters. The authors also obtained stroke incidence from implantation to one year post-LVAD implantation.

A total of 311 continuous-flow LVADs were implanted in the study hospital during the study period, with 75 patients from that cohort meeting study inclusion criteria. The study results indicated no significant differences in baseline demographics in patients who suffered stroke versus those who didn’t. The authors reported that patients who did have stroke had a more acute angulation of outflow cannula relative to the aorta versus patients who did not have stroke (42⁰ versus 65⁰, respectively; P=0.026). Patients with stroke also had smaller diameter of anastomosis of the outflow cannula compared to those without stroke (1.3 cm vs. 1.5 cm, respectively; P=0.013). There was no association between the inflow cannula position and the incidence of stroke.

“Our study shows that LVAD outflow cannula orientation and size of anastomosis portend a higher risk of subsequent stroke,” the researchers concluded. “Therefore, it is imperative to optimize LVAD surgical implant techniques and device manufacturing to allow larger anastomosis site and less acute angulation of the outflow cannula.”

Argawal T, Marcos-Abdala H, Araujo-Guitierrez, et al. J Card Fail. 2019;25(8);S12. Abstract 029.