Hyperlactatemia as a prognostic indicator for contemporary left ventricular assist device implantation.

Background: This study evaluates the impact of early post-operative hyperlactatemia on outcomes after left ventricular assist device (LVAD) implantation.

Methods: Adults undergoing contemporary LVAD implantation between 2009 to 2018 were included. Peak post-operative (within 24-h) lactate level was analyzed. The cohort was stratified into patients with and without post-operative hyperlactatemia, which was defined as peak > 3.5 mMol/L. The primary outcome was survival, and secondary outcomes included post-implant adverse events. Sub-analysis was performed to evaluate the impact of time for lactate normalization, define as lactate < 2 mMol/L. Multivariable cox regression was used for risk-adjustment.

Results: A total of 190 patients were included. 49.5% experienced early post-operative hyperlactatemia. Patients with post-operative hyperlactatemia had significantly higher rates of post-implant complications including re-operation, renal failure, and hepatic dysfunction (all, p ≤ 0.05). The post-operative hyperlactatemia group also had significantly higher 90-day and 1-year mortality rates following LVAD implantation (both, p ≤ 0.05). In multivariable analysis, post-operative hyperlactatemia (HR 1.69, 95% CI 1.09-2.60, p = 0.02) was an independent predictor of overall mortality following LVAD implantation. Increased time for normalization of lactate also adversely impacted risk-adjusted overall mortality following implantation as a continuous variable (HR 1.02, 95% CI 1.01-1.03, p < .001).

Conclusions: This study demonstrates early post-operative hyperlactatemia is associated with increased morbidity and mortality following LVAD implantation. Even early post-operative lactate trends within the first 24 post-operative hours appear to have a useful role in predicting longitudinal survival following implantation. Careful monitoring of post-operative lactate with measures to normalize levels should be considered in the early care of LVAD patients.