Survival After Left Ventricular Assist Device: A Society of Thoracic Surgeons National Intermacs Database Risk Model...

Several left ventricular assist device (LVAD) risk models exist; however, currently, only 1 LVAD is available. Therefore, we assessed prognostic accuracy of including data from other durable LVADs vs fully magnetic devices only in 3-year survival models.

All patients receiving primary continuous flow LVADs in The Society of Thoracic Surgeons National Intermacs (Interagency Registry for Mechanically Assisted Circulatory Support) Database (January 2013-April 2023) were included. Patients were stratified into 3 cohorts: cohort 1, fully magnetic devices only, 2018-2023 (n = 12,449); cohort 2, hydrodynamic and magnetically levitated and axial flow devices, 2018-2023 (n = 3235); and cohort 3, hydrodynamic and magnetically levitated and axial flow devices, 2013-2017 (n = 14,019). Machine learning multivariable oblique random survival forests compared 3 models predicting 3-year survival in testing sets from the fully magnetic cohort. Model 1 included only cohort 1 patients; model 2 included cohorts 1 and 2; and model 3 included cohorts 1, 2, and 3.

Of the patients with fully magnetic LVADs, 2552 (20.5%) died within 3 years of implantation. Model discrimination, assessed by mean time-dependent area under the curve, was similar for all 3 models (0.706, 0.700, and 0.706). Calibration evaluated by time-dependent delta Brier score demonstrated that model 1 had superior performance compared with model 2 (P = .016) and model 3 (P = .038), particularly after the first-year following implantation.

Models including data from older/alternative durable LVADs showed similar or inferior performance compared with a model using fully magnetic device-only patients. These findings support current methodology including only patients receiving fully magnetic LVADs while also providing a framework for model comparisons in future device eras.