A simple approach to risk stratification in adult heart transplantation

Abstract

Objective: While there are numerous reports in the literature of risk factors for graft failure after heart transplantation, simple models for risk stratification are lacking. This study describes a simple method for risk stratification in adult heart transplantation that can be applied when the size of a dataset is insufficient for formal regression modelling.

Methods: Multi-centre prospective cohort study. Fourteen risk factors documented in the literature as increasing post transplant graft failure were used to formulate a model. Risk factors included in the model were recipient age >50 years, pre-operative ventilatory support, pre-operative circulatory support, >1 previous sternotomy, pulmonary vascular resistance >2.5 wood units, male with body surface area >2.5 m2, retransplant, ischaemic time >3.5 h, donor age >45 years, donor inotropic support >10 microg/kg per min dopamine, female donor, ratio donor/recipient body surface area <0.7, donor with diabetes and history of donor drug abuse. Four risk groups were defined depending on the number of risk factors present: Low, none; moderate, 1; high, 2 or 3; very high, 4 or more. Graft survival to 30 days was chosen as the primary outcome. The model was tested on 373 adult transplants performed in the UK between April 1995 and December 1996.

Results: Twenty eight transplants were low risk, 82 moderate, 201 high and 62 very high. The 30-day survival (70% CI) for the risk groups was low, 97% (93-100), moderate 95% (92-98), high 87% (84-89) and very high 80% (75-83) (P = 0.02).

Conclusions: This preliminary model enables some stratification of heart transplant procedures according to donor and recipient risk profile. Further work will be directed at refining and validating the model.