Creation of a quantitative recipient risk index for mortality prediction after cardiac transplantation (IMPACT)

Eric S. Weiss, Jeremiah G. Allen, George J. Arnaoutakis, Timothy J. George, Stuart D. Russell, Ashish S. Shah, John Conte

Research output: Contribution to journalArticlepeer-review

190 Scopus citations


Background: No recipient risk index exists predicting short-term mortality after orthotopic heart transplantation (OHT). We utilized United Network for Organ Sharing (UNOS) data to develop a novel quantitative recipient risk score for use in OHT. Methods: A prospectively collected open cohort of 21,378 primary OHT patients (1997 to 2008) was randomly divided into subgroups. The training cohort (n = 17,079) was used for score derivation and the test cohort (n = 4,299) was used for independent validation. Recipient specific variables associated with 1-year mortality (exploratory p value < 0.2) were incorporated stepwise into a multivariable logistic regression model. The final model contained variables which maximized explanatory power (assessed by pseudo R2, area under the curve, and likelihood-ratio test). A risk index was created by apportioning points approximating the relative impact of variables on 1-year mortality. The Kaplan-Meier method was used to assess impact of risk score on short-term survival. Results: The 50-point scoring system incorporated 12 recipient specific variables. Derivation and validation cohort scores ranged from 0 to 33 and 0 to 27, respectively (mean 6.1 ± 3.7 and 6.1 ± 3.7). Each point increased the odds of 1-year death by 14% in the derivation cohort (odds ratio 1.14 [1.13 to 1.15], p < 0.001) and 15% in the validation cohort (odds ratio 1.15 [1.12 to 1.17], p < 0001). One-year survivals in the validation cohort (by increments of 3 points) were the following: 0 to 2 (92.5%); 3 to 5 (89.9%); 7 to 9 (86.3%); and 10 or greater (74.9%); p < 0.001. Patients transplanted with risk scores of 20 or higher had 1-year mortality rates greater than 50%. Conclusions: We present a novel internally validated OHT recipient risk score, which is highly predictive of 1-year mortality. This risk index may prove valuable for patient prognosis, organ allocation, and research stratification in OHT.

Original languageEnglish (US)
Pages (from-to)914-922
Number of pages9
JournalAnnals of Thoracic Surgery
Issue number3
StatePublished - Sep 2011

All Science Journal Classification (ASJC) codes

  • Surgery
  • Pulmonary and Respiratory Medicine
  • Cardiology and Cardiovascular Medicine


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