RADIAL: a novel primary graft failure risk score in heart transplantation

Primary graft failure (PGF) is the leading cause of early mortality after heart transplantation (HT). Our aim is to propose a working definition of PGF and to develop a predictive risk score.

PGF was defined by four criteria reflecting significant myocardial dysfunction, severe hemodynamic impairment, early onset after HT, and absence of secondary causes of graft dysfunction. We identified independent risk factors for PGF in a derivation series of 621 HTs and constructed a predictive model. After proving its internal consistency we tested the model in a prospective validation series.

The incidence and lethality of PGF in our series were 9% and 80%, respectively. We identified 6 multivariate risk factors for PGF (Right atrial pressure ≥ 10 mm Hg, recipient Age ≥ 60 years, Diabetes mellitus, Inotrope dependence, donor Age ≥ 30 years, Length of ischemic time ≥ 240 minutes--i.e., RADIAL). Analysis of isolated right ventricular failure showed similar predictors. The RADIAL score was obtained by adding 1 point for each of these factors present in a given HT. PGF incidence increased significantly as the RADIAL score increased (p < 0.001 for trend). Rates of actual and predicted PGF incidence for RADIAL subgroups showed a good correlation (C-statistic = 0.74). In a prospective validation cohort, RADIAL score kept its predictive ability.

PGF as defined by these criteria showed a high impact on early post-HT mortality in our series. The RADIAL score showed good ability to predict the development of PGF, and could be useful in the prevention and early treatment of this complication.