New-onset graft dysfunction after heart transplantation--incidence and mechanism-related outcomes.

BACKGROUND: Graft dysfunction (GD) after heart transplantation (HTx) is a major cause of morbidity and mortality. The impact of different pathophysiologic mechanisms on outcome is unknown. In this large, single-center study we aimed to assess the incidence of GD and compare the outcomes with different histopathologic mechanisms of rejection.
METHODS: We analyzed a data set of 1,099 consecutive patients after their HTx at Columbia University Medical Center between January 1994 and March 2008, and identified all patients hospitalized with new-onset GD. Based on the histopathologic data, patients were divided into GD-unexplained (Group-GD-U), GD-antibody-mediated rejection (Group-GD-AMR), GD-cardiac allograft vasculopathy (Group-GD-CAV) and GD-acute cellular rejection (Group-GD-ACR) groups. We compared the in-hospital and 3-, 6- and 12-month mortality across these groups using the chi-square test. We also compared the 3-, 6- and 12-month survival curves across groups using the log-rank test.
RESULTS: Of 126 patients (12%) identified with GD, complete histology data were available for 100 patients. There were 21, 20, 27 and 32 patients identified in Group-GD-U, Group-GD-AMR, Group-GD-CAV and Group-GD-ACR, respectively. The in-hospital mortality rates were 52%, 20%, 15% and 6%, respectively. The in-hospital mortality rate was significantly higher in Group-GD-U compared with all other groups (p = 0.0006). The 3-, 6- and 12-month survival rate was also significantly lower in Group-GD-U compared with all other groups.
CONCLUSION: A significant proportion of patients presenting with new-onset GD have unexplained histopathology. Unexplained GD is associated with a significantly higher mortality rate. New diagnostic tools are necessary to better understand and detect/predict this malignant phenotype. Crown