999-117 Computerization of the Application of Parametric Multivariable Risk Factor Analyses to Estimate the Risk of Events After Cardiac Transplantation

Abstract

The consideration of multivariable analysis derived risk factors for post transplant events in the evaluation of potential cardiac transplant recipients and donors may serve to improve mortality and morbidity after cardiac transplantation. However, the application of this information is elusive due to the difficulty of applying all identified recipient and donor related risk factors, expressed as dichotomous and continuous variables, in the assessment of the risk of post transplant events for a single patient. The CTRD has reported multivariable risk factor analyses in the hazard function domain for post cardiac transplant events from all primary transplants from 30 transplant centers with 4.5 year follow-up. Variables analyzed in theses reports included multiple recipient and donor demographic information, recipient and donor mismatch variables, pre-transplant recipient and donor clinical variables, hemodynamic variables, surgical variables, initial immunosuppression variables, and post transplant event variables. Specific risk factors for post transplant events were identified and multivariable equations were derived and have been published. In order to facilitate the application of this information, a computer program was developed to allow the calculation of the estimated time-related risk of post transplant events including death, time to first infection, time to first rejection, and number of rejections in the first year. One enters the values for specified variables into the program. The program then calculates (utilizing solutions to the multivariable equations) and then displays the time-related actuarial and hazard function curves, with standard errors, for each event in graphical and tabular formats. Patient data may be stored, and data output may be printed. Different patients or clinical situations for the same patient may be compared on screen. The program is written in Microsoft C, version 6, and runs in PC-DOS. Computer requirements include 640 kb RAM, VGA graphics, and a floating point processor. Utilizing this software package, a clinician may compute and print an individual patient's time related risk profiles for post transplant death, infection, and allograft rejection. This information may be used for pre-transplant recipient education and selection, and donor-recipient matching prior to transplantation.