Introduction and objectives: Heart transplantation (HT) is the gold standard treatment for patients with end-stage heart failure. It significantly reduces mortality and improves quality of life. However, the availability of donors limits the number of heart transplants. The aim of this study is to evaluate donor and recipient risk factors associated with survival within one year of heart transplantation in a reference center in Latin America and to derive a mortality risk index for heart transplant patients on the waiting list.
Methods: A single-center retrospective cohort study evaluated 310 adult patients who underwent transplantation at the Heart Institute (Incor HC-FMUSP) between January 2013 and December 2019. Univariate and multivariate Cox regression analyses were conducted to identify independent predictors of 1-year survival among well-established prognostic clinical characteristics described in the literature. Patients were followed until death or the last observation on October 12, 2022. The analysis of donor and recipient data in 299 heart transplant cases with complete medical records resulted in a final model of clinical variables that showed statistical significance. A simple risk index was created based on the hazard ratio of each factor.
Results: Four variables observed during the last clinical assessment in the Intensive Care Unit (ICU) within 24 hours before surgery were statistically significant in predicting one-year survival after HT: maximum SOFA score (< 5 and >=5), creatinine clearance (ml/min/1.73 m2) in 3 quartile categories (>= 84 between 42 and 84 and <= 42), C-reactive protein (CRP) (mg/dL) in 3 categories (<= 6 between 6 and 33 and >=33) and white blood cell count (WBC) (leukocytes /mm3) in 3 categories (<=5590 between 5590 and 9237 and >=9237). The model demonstrated good discrimination (C-Index=0.74) and calibration. The group at high risk (>20 points) exhibited significantly higher mortality rates at 30 days and 1 year compared to the low-risk group (<=20 points), with rates of 27.6% and 44%, respectively, versus 7.9% and 14.6%, respectively (p<0.001).
Conclusions: This analysis identified four independent predictors of survival one year after heart transplantation (HT): maximum SOFA score greater than 5, creatinine clearance less than 40 ml/min/1.73 m2, CRP level higher than 33 mg/L, and absolute leukocyte count greater than 9200/mm3. These factors were analyzed in the ICU 24 hours before HT and were found to be independent predictors of reduced survival one year after HT.