Developing a Risk Score to Predict Mortality in the First Year After ICD implantation. Data from the Israeli ICD Registry

Roman Nevzorov ICCU, Barzilai University Medical Center, Ashqelon Ilan Goldenberg Cardiology Department, Sheba Medical Center, Tel Hashomer, Israel Yuval Konstantino Electrophysiology and Pacing Unit, Soroka University Medical Center, Beer Sheva, Israel Gregory Golovchiner Electrophysiology and Pacing Unit, Rabin Medical Center, Petach-Tikva, Israel Boris Strasberg Electrophysiology and Pacing Unit, Rabin Medical Center, Petach-Tikva, Israel Mahmoud Souleiman Electrophysiology and Pacing Unit, Rambam Health Care Campus, Haifa, Israel Vladimir Khalameizer Electrophysiology and Pacing Unit, Barzilai University Medical Center, Ashqelon, Israel Ron Sela Electrophysiology and Pacing Unit, Galilee Medical Center, Nahariya, Israel Shimon Rosenheck Electrophysiology and Pacing Unit, Meir Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Kfar Saba Nahum A. Freedberg Electrophysiology and Pacing Unit, HaEmek Medical Center, Afula, Israel Michael Geist Electrophysiology and Pacing Unit, Edith Wolfson Hospital, Holon, Israel Natalie Gabrielov-Yusim Cardiac Research Center, Sheba Medical Center, Ramat Gan, Israel Diklah Geva Cardiac Research Center, Sheba Medical Center, Ramat Gan, Israel Michael Glikson Electrophysiology and Pacing Unit, Sheba Medical Center, Ramat Gan, Israel Moti Haim Electrophysiology and Pacing Unit, Soroka University Medical Center, Beer Sheva, Israel

Background: Although ICD implantation is an effective therapy in specific groups of patients, in some patients ICD Implantation is less effective or not effective at all in preventing death. Life expectancy of less than 1 year is usually a contraindication for ICD implantation.

Aim: To develop a model aiming to identify patients at risk of death during the first year after Implantable Cardioverter Defibrillator (ICD) implantation

Methods: Patient population was derived from the Israeli ICD Registry - a prospective national registry of all patients that were implanted with an ICD or received cardiac resynchronization therapy with a defibrillator (CRT-D) in Israel. Two groups of patients were compared: those who died during the first year after ICD implantation and those who were still alive one year after ICD implantation. Factors associated with 1 year mortality were identified on a derivation cohort (n= 1306) and a risk score was established. It was validated on a validation cohort (n= 1310) Association between the score and 1 year mortality was examined.

Results: A total of 2617 patients have completed at least one year of follow up after first-time ICD or CRTD implantation at 22 centers. In the initial cohort (n=1306) during first year after ICD implantation there were 63 (4.8%) fatal events. Age > 75 years (hazard ratio [HR]:2.7; 95% confidence interval[CI]: 1.6 to 4.4) , history of atrial fibrillation (HR: 1.9; 95% CI: 1.12 to 3.17), chronic lung disease ( HR:2.0; 95% CI: 1.1 to 3.76) , anemia (Hb level less than 13 Gr/dl in men and less than 12 Gr /dl in women ) (HR: 2.3; 95% CI: 1.3 to 3.93) and eGFR level < 30 min/ml/1.73mÂ²)( HR: 3.4; 95% CI: 1.74 to 6.6) were found to be independent risk factors for one-year mortality after ICD implantation. We propose a simple score for prediction of one year mortality after ICD implantation ("triple A , double C " AAACC) including : Age more than 75 years (3 points), Anemia (2 points), history of Atrial fibrillation (1 point), significant Chronic renal failure (GFR< 30 min/ml/1.73mÂ² (3 points) and Chronic lung disease (1 point). Mortality risk increased with increasing number of points on the score. Risk of 1 year death increased from 1% in pts with 0 points toÂ 12.5%Â in pots with score >4. The risk score was evaluated with ROC curve and the AUC of the validation curve is 0.71 (95% CI 0.66-0.76) which indicates fair to good prognostic value of the developed 1 year mortality score.Â

Conclusions: In the present study advanced age (more than 75 years), history of atrial fibrillation, chronic lung disease, anemia and decreased eGFR level (< 30 min/ml/1.73mÂ²) were found as independent risk factors for one-year mortality after ICD implantation. The resulting AAACC risk score that consists of clinical parameters may identify patients at high risk of death during one year after ICD implantation

Roman Nevzorov

Israel