Prognostic value of vasoactive-inotropic score following continuous flow left ventricular assist device implantation

Background: The purpose of this study is to evaluate the utility of vasoactive-inotropic score (VIS) in predicting outcomes after left ventricular assist device (LVAD) implantation and explore possible mechanisms of post-operative hemodynamic instability.

Methods: Retrospective review was performed in 418 consecutive patients with LVAD implantation. VIS was calculated as dopamine + dobutamine + 10 × milrinone + 100 × epinephrine + 100 × norepinephrine (all μg/kg/min) + 10000 × vasopressin (U/kg/min) after initial stabilization in the operating room and upon arrival at the intensive care unit. The primary outcome was in-hospital mortality. The secondary outcomes were a composite of in-hospital mortality, delayed right ventricular assist device (RVAD) implantation, and continuous renal replacement therapy. The pre-operative biomarkers of inflammation, oxidative stress, endotoxemia and gut-derived metabolite trimethylamine-N-oxide (TMAO) were measured in a subset of 61 patients.

Results: Median VIS was 20.0 (interquartile range 13.3-27.9). VIS was an independent predictor of in-hospital mortality (odds ratio [OR] 1.06, 95% confidence interval [CI] 1.03-1.09, p < 0.001) and composite outcome (OR 1.03, 95% CI 1.01-1.06, p = 0.008). In-hospital mortality increased for each VIS quartile (0% vs 3.9% vs 7.6% vs 12.3%, p = 0.002). VIS was superior to other established LVAD risk models as a predictor of in-hospital mortality (area under the curve 0.73, 95% CI 0.64-0.82). The optimal cut-off point for VIS as a predictor of in-hospital mortality was 20. Pre-operative hemoglobin level was the only independent predictor of VIS ≥ 20 (p = 0.003). Patients with a high VIS were more likely to have elevated TMAO pre-operatively (53.6% vs 25.8%, p = 0.03).

Conclusions: A high post-operative VIS is associated with adverse in-hospital outcomes and is a better predictor of in-hospital mortality compared with existing LVAD risk models. Whether early hemodynamic stabilization using RVAD may benefit patients with a high VIS remains to be investigated.