Implantation of an intra-aortic balloon pump (IABP) did not improve 60-day survival or bridge to heart replacement (HRT) therapies in patients with heart failure-cardiogenic shock (HF-CS) compared to standard care, according to a study presented during a Featured Clinical Research session at ACC.25 in Chicago and simultaneously published in JACC. The trial was stopped by the Data Safety and Monitoring Board at the prespecified interim analysis due to futility.

In the multicenter, prospective Altshock-2 study, conducted in seven centers across Italy from 2020 to 2024, 101 patients (median age 60 years, 80% men) were randomized to either IABP and standard care (n=53) or standard care (n=48). The Society for Cardiovascular Interventions stage for HF-CS was stage B in 28%, stage C in 57% and stage D in 15%.

Results showed that at 60 days, 81% of patients in the IABP group and 75% in the control group reached the primary endpoint of survival or successful bridge to HRT (hazard ratio, 0.72; p=0.45). Among patients, four (7.5%) in the IABP arm and two (4.2%) in standard care were escalated to another temporary mechanical circulatory support (tMCS); six (13%) in standard care were moved to IABP. Complications were comparable between the two groups.

"This was the largest trial designed to enroll patients with cardiogenic shock due to [HF] to assess the hypothesis that early intervention with the IABP would improve patient survival compared with standard care," said Alice Sacco, MD, a co-principal investigator on the study. "These results show that early IABP use should not be the default approach to temporary mechanical support of the heart."

In an accompanying editorial comment, Clément Delmas, MD, PhD, et al., call the study "bursting the balloon" of IABP for CS, and write that, "Based on the Altshock-2 results, there is probably no place for IABP as bridge to HRT." They note the study, "advocates for the revision of guidelines to support a class IIIB recommendation for the routine use of IABP in HF-CS patients." They also note the results support changing the current heart allocation score, which currently prioritizes CS patients under IABP support. "Although a few rare indications may still justify the use of IABP, the device's days seem to be numbered."

An additional editorial comment by Alastair G. Proudfoot, MD, PhD, et al., notes that 90% of screened patients were excluded, and that, "The small sample size and substantial crossover (13%) leave the possibility of an unrecognized benefit widely open." They write that, "Large scale, pragmatic clinical trials should interrogate standard of care, including MCS management such as anticoagulation and vascular access strategies. In parallel, we need more ambitious, international [randomized controlled trials], performed across all continents and adequately powered to test the efficacy of MCS devices."