Impact of postoperative hyperlactatemia in orthotopic heart transplantation.

Hyperlactatemia (HL) is a common phenomenon after cardiac surgery which is related to tissue hypoperfusion and hypoxia and associated with poor outcomes. It is also often seen in the postoperative period after orthotopic heart transplantation (OHTx), but the association between HL and outcomes after OHTx is not well known. We evaluated the incidence and outcome of HL after OHTx. This was a retrospective study of 209 patients who underwent OHTx between January 2011 and December 2020. Patients were classified into 3 groups according to their peak lactate levels within the first 72 h postoperatively: group 1, normal to mild hyperlactatemia (<5 mmol/L, n = 42); group 2, moderate hyperlactatemia (5–10 mmol/L, n = 110); and group 3, severe hyperlactatemia (>10 mmol/L, n = 57). The primary composite endpoint was all-cause mortality or postoperative initiation of veno-arterial extracorporeal membrane oxygenation (VA ECMO) within 30 days. Secondary endpoints included duration of mechanical ventilation, intensive care unit length of stay, and hospital length of stay. Patients with higher postoperative peak lactate levels were more commonly transplanted from left ventricular assist device support (33.3 % vs 50.9 % vs 64.9, p < 0.01) and had longer cardiopulmonary bypass time [127 min (109–148) vs 141 min (116–186) vs 153 min (127–182), p = 0.02]. Composite primary endpoint was met in 18 patients (8.6 %) and was significantly more common in patients with higher postoperative peak lactate levels (0.0 % vs 6.4 % vs 19.3 %, p < 0.01). Severe hyperlactatemia following orthotopic heart transplant was associated with an increased risk of post-transplant VA ECMO initiation and mortality at 30 days. [Display omitted] • Postoperative hyperlactatemia (HL) >5 mmol/L was seen in 79.9% of patients after OHTx. • Postoperative HL was associated with a higher rate of death and or use of VA ECMO. • Threshold value was high around 10 mmol/L (sensitivity 61.1%, specificity 75.9%). • Total ischemic time was not significantly associated with the peak lactate levels. • Cardiopulmonary bypass time and preoperative durable left ventricular assist device were associated with postoperative severe HL. [ABSTRACT FROM AUTHOR]