LAUSR

Purpose The aim of the study was to evaluate the trend of all the three type of rejection, cellular, humoral and mixed, during 6 years of follow-up , from 2012 to 2017 at the our transplant center, to evaluate pre-transplant clinical predictive factors for acute rejections and mortality. Methods We evaluated 149 patients heart transplanted adult patients transplanted from January 2012 and December 2017 at the university of Padua . Post transplant monitoring EMBs from 2012 to December 2018 were reevaluated . All the pre-transplant clinical were collected in a data base. The statistical analysis was subdivided in two parts. In the first part we analyzed the trend of the three different type of rejections, calculated the rate expressed as a average number of rejections for patients per year, with a Poisson distribution. In the second part we applied Machine learning method (ML), and algorithm Random Forest (RF) to analyzed the pre-transplant factors for the onset of acute rejections and for mortality. Results Of the 149 pts , 108(72,5%) were male and 41 (27,5%) female, mean age at transplantation 53,7±11,9 years for male and 46,2±15,4 for female. Two thousand and thirty three EMBs were performed during follow up with a mean number of 13,5±4,27 EMBs per patient. Of these , 1163 (57,2%) were negative for rejection, 31 (1,5%) positive for humoral rejection (pAMR+), 796 (39,2%) positive for ACR , 43 (2,1%) positive for mixed rejection. For all type of rejection there were a decreasing trend during the 6 years of follow up. The reduction in the mean number of rejection was 53,4% for acute rejection. Pre transplant predictive factors of cellular rejection were the pathology leading to heart transplant with a predictive value of 0,9%, age at transplant with a value of 0,8%. For humoral rejection the predictive factors were preforming antibodies anti HLA class II with a predictive value of 1,9%, previous pregnancies and miscarriage with a predictive value of 1,8% . The risk of mortality was influenced by age of donor with a risk value of 7,8%, the age at transplant with a risk value of 6,6%. Conclusion We have demonstrated that there is a decreasing trend of the three types of rejection during the last 6 years of follow up, in particular of cellular rejection. This is not in relation with changing in immunosuppressive drugs , but probably is due to pre and postoperative better management of heart transplant patients.