Postoperative Veno-arterial PCO2 gap and Lactate Levels as Predictors of Primary Graft Dysfunction after Orthotopic Heart Transplant

Shreyas Kiran1, Phoebe Miller MD, MS2, Andrew Akcelik MD3, Jason Smith MD3, Amy G. Fiedler MD3

1School of Medicine, University of California, San Francisco, CA ; 2Department of Surgery, University of California, San Francisco, CA; 3Department of Cardiothoracic Surgery, University of California, San Francisco, CA

Orthotopic heart transplantation (OHT) remains the gold standard treatment for patients with end-stage heart failure. In the immediate postoperative period, cardiac surgeons often observe elevated lactate levels and an increased venoarterial carbon dioxide partial pressure gradient (V–a PCO₂). While these findings are common after OHT, their clinical relevance and potential prognostic value are not well defined. In particular, few studies have systematically evaluated whether postoperative lactate or V–a PCO₂ levels are associated with primary graft dysfunction (PGD), a major cause of early morbidity and mortality following heart transplantation. Clarifying this relationship may help identify early markers of graft dysfunction and improve postoperative monitoring and management strategies.