Using INTERMACS(IM) to Establish Objective Performance Criteria (OPC) for Clinical Trials in “Less Sick” Advanced CHF Patients: An Analysis of the STS IM Database

Abstract

Purpose Future durable MCS devices are designed to be less invasive, delivered via non-central arterial access and provide partial support. They will be true assist devices and require residual cardiac reserve, ie. the “less sick” advanced CHF population. Lacking equipoise to perform randomized trials with approved LVADs, single arm trials with OPC will be needed to get regulatory approval. This study analyzes IM for completeness and validity and to determine its ability to 1) define the real-world “less sick” patient group and 2) establish OPCs for future MCS trials. Methods Inclusion - IM patients > 45 years, profiles 1-5 and implanted between 2014-2016 with durable LVADs. Patients were stratified into IM1-2 and IM3-5 groups. They were also stratified to real-world sick (S) and less sick (LS) groups using pre-implant hemodynamics (CI 20 mmHg) and the amount of inotropic/temporary MSC support. Survival, transplant rates, adverse events, 6 min walk test and KCCQ were obtained for the 4 groups at 6 and 12 months. Results 6509 patients met inclusion criteria. Patients were grouped into IM1-2 (n=3084), IM3-5 (n=3425), S (n=4026), and LS (n=1808). Re-categorization occurred in 11% from IM1-2 to LS and 43% from IM3-5 to S. 675 patients (10%) could not be placed into the S or LS groups due to lack of pre-implant hemodynamic data. Outcomes (survival, transplanted, death) at 6 and 12 months were similar between the S group and IM1-2 group as well as the LS group and IM3-5 group. Outcomes, adverse events and performance status are reported in table 1. Conclusion Patients in the IM database can be classified by hemodynamic assessment and inotrope/temporary MCS support into a better defined LS patient group than using physician assigned profiles. Interestingly, AEs and outcomes were similar across groups reflecting class effects of current LVADs . IM can be used to establish real-world LS group and OPCs for future single armed MCS trials.