Prognostic Implication of Longitudinal and Peak Lactate Levels after LVAD Implantation

Abstract

Serial measurements of lactate levels are commonly performed after LVAD implantation, but the prognostic implications have not been well studied. The objective of this study is to evaluate the association of lactic acid levels with in-hospital mortality, after LVAD implantation. We retrospectively identified all patients at our Institution who underwent implantation of a durable LVAD between 1/1/2009 and 12/1/2018 and had lactate levels recorded in the immediate 48-hour postoperative period (n=507). We excluded patients who received biventricular mechanical support (N=19). Baseline characteristics were compared using T-test/Wilcoxon rank-sum test and Chi squared test. Multivariable logistic regression was used to assess peak-lactate levels between those who were discharge alive after index LVAD implant hospitalization (S-group) vs. those who died during the index hospitalization (M-group). A total of 488 patients were included in the analysis. The baseline characteristics of the S-group (N=432) and the M-group (N=56) are compared in the Table. The two groups had similar preimplant lactate levels (1.1 [0.9-1.4] vs. 1.0 [0.9-1.3] mmol/L, p=0.72). However, peak lactate levels were significantly lower in the S-group compared to the M-group (2.8 [2.0-4.2] vs. 4.6 [2.8-6.9] mmol/L, p<0.0001). Furthermore, the time to peak lactate was significantly lower in the S-group compared to the M-group (4.9 [3.1-9.8] vs. 9.2 [4.4-21.8] hours, p<0.0001). After adjusting for age, sex, BMI, race, LVAD type, INTERMACS profile and ischemic cardiomyopathy, peak lactate was significantly associated with mortality during the index admission OR: 1.2 (95% CI: 1.1-1.4), p=0.001. Lactate level in the first 48-hours after LVAD implantation surgery is an independent predictor of mortality. Further research is needed to assess the mechanisms responsible for elevated postoperative lactate levels and whether targeted therapy will improve clinical outcomes. Baseline Characteristics.