Are the Clinical Implications of Lactic Acidosis Similar Post-Cardiac Transplantation Verus Post-LVAD Implantation?

Abstract

Purpose Lactic acidosis is common in critically ill patients and is frequently observed early post orthotopic heart transplantation (OHT). Several mechanisms have been postulated to explain this finding including circulatory shock, use of high-dose inotropes and vasopressors, metabolic derangements from chronic advanced heart failure, or from high dose corticosteroid immunosuppression. Our objective was to determine if lactic acidosis after OHT had the same characteristics and effect on postoperative outcomes as lactic acidosis observed after elective left ventricular assist device implantation (LVAD). Methods and Materials We retrospectively reviewed plasma pH, lactate and glucose levels for the first 48 hours post-op and determined 30 day mortality in 279 adult patients who received OHT or LVAD with in the UTAH Cardiac Transplant Program in Salt Lake City, Utah between Jan 1, 2000 and October 31, 2012. Comparisons between OHT and LVAD at the time point of peak lactate level were made using Student T test. Mortality at 30 days was analyzed by chi-square test. A p value Results [Table 1] Conclusions Patients undergoing OHT have a greater degree of post-operative lactic acidosis and hyperglycemia then patients undergoing LVAD. However, OHT patients had a better 30 day outcome compared to LVAD patients. This suggests that the lactic acidosis may be transient and a more benign disorder post OHT. A possible explanation may be induction of a type B lactic acidosis with corticosteroids after OHT but further studies are necessary. OHT (n = 146) LVAD (n=133) p pH 7.28±0.08 7.39±0.07 Lactate (mmol/L) 7.73±4.27 4.22±3.78 Glucose (mg/dL) 209±63 150± 41 Deaths at 30 days 1 (0.7%) 8 (6.0%) 0.012