Outflow Graft Narrowing of the HeartMate 3 Left Ventricular Assist Device

Background: In patients with the HeartMate 3 (HM3, Abbott) left ventricular (LV) assist device (LVAD), outflow graft narrowing has been reported as a result of accumulation of biodebris either internal or external to the graft. This study describes the prevalence, imaging findings, and clinical outcomes associated with HM3 LVAD outflow graft narrowing.

Methods: A single-center retrospective cohort study was performed in patients who received an HM3 LVAD between November 2014 and July 2019. All patients with a computed tomographic (CT) angiogram or a CT scan with intravenous contrast sufficient to evaluate the outflow graft lumen were included. Narrowing was defined as a hypodensity of ≥3 mm.

Results: Of 165 HM3 LVAD recipients, 46 (28%) had qualifying imaging. Outflow graft narrowing was present in 33% (15/46). One patient had complete obstruction requiring emergency surgery, whereas 14 patients had a median hypodensity of 4.5 mm (interquartile range, 3.3-5.8 mm). The presence of outflow graft narrowing was significantly associated with a longer duration of LVAD support (588.2 ± 277.5 days vs 131.5 ± 170.9 days; P < .0001). One-year survival after identification of narrowing was 93%, with death occurring in 1 patient with complete obstruction. LV unloading (mean percent decrease in LV end-diastolic diameter at time of CT imaging vs pre-LVAD) was 16.7% vs 17.7% in patients with and without narrowing, respectively (P = .86).

Conclusions: Among patients with adequate imaging, one-third have evidence of narrowing. Outflow graft narrowing secondary to biodebris was more likely to be found in HM3 LVAD recipients with longer duration of LVAD support. There was no significant difference in LV unloading between patients with and without narrowing.