Postoperative cognitive dysfunction and mortality following lung transplantation

Preliminary evidence suggests that postoperative cognitive dysfunction (POCD) is common after lung transplantation. The impact of POCD on clinical outcomes has yet to be studied. The association between POCD and longer-term survival was therefore examined in a pilot study of posttransplantation survivors. Forty-nine participants from a prior randomized clinical trial underwent a neurocognitive assessment battery pretransplantation and 6 months posttransplantation, including assessments of the domains of Executive Function (Trail Making Test, Stroop, Digit Span), Processing Speed (Ruff 2 and 7 Test, Digit Symbol Substitution Test), and Verbal Memory (Verbal Paired Associates, Logical Memory, Animal Naming, and Controlled Oral Word Association Test). During a 13-year follow-up, 33 (67%) participants died. Greater neurocognition was associated with longer survival (hazard ratio [HR]=0.49 [0.25-0.96], P=.039), and this association was strongest on tests assessing Processing Speed (HR = 0.58 [0.36-0.95], P=.03) and Executive Function (HR=0.52 [0.28-0.97], P=.040). In addition, unadjusted analyses suggested an association between greater Memory performance and lower risk of CLAD (HR=0.54 [0.29-1.00], P=.050). Declines in Executive Function tended to be predictive of worse survival. These preliminary findings suggest that postoperative neurocognition is predictive of subsequent mortality among lung transplant recipients. Further research is needed to confirm these findings in a larger sample and to examine mechanisms responsible for this relationship. Greater neurocognitive performance independently predicts greater long-term survival following lung transplantation, particularly on tests of executive function and processing speed.