Impact of partial- to full-support escalation with microaxial flow pumps prior to durable left ventricular assist device implantation

Objectives: Microaxial flow pumps (mAFP) effectively bridge cardiogenic shock patients to durable left ventricular assist device (dLVAD) implantation. The partial-support mAFPs provide only up to 3.5 L/min, which might be insufficient for an effective circulatory support and preconditioning for a dLVAD implantation. Alternatively, patients with refractory shock on partial-support may benefit from an escalation to a full-support mAFP. Methods: A retrospective analysis of 130 patients was performed across 17 European cardiac centers who underwent dLVAD implantation following mAFP with or without venoarterial extracorporeal life support (VA-ECLS) between February 2015 and August 2022. Ninety-two patients (70.8%) were bridged on partial-support mAFP, while 38 patients (29.2%) underwent an escalation to full-support mAFP. Results: Median support duration was significantly longer in the escalation group (7d [4, 11] vs 12d [9, 21], p < 0.001). Patients in the escalation group were more likely to be weaned from va-ECLS before dLVAD implantation, 10 (71.4%) vs 6 (11.3%), p < 0.001. 30-day survival was similar between the escalation and no-escalation groups, 89.5% vs 84.8% (IPTW-weighted OR 1.00 [95% CI: 0.46, 2.22], p = 0.992). Estimated 1-year survival was higher in the escalation group: 84.0% [95% CI: 73.0, 96.6] vs 63.7% [95% CI: 54.3, 74.6], HR 0.41 [95% CI: 0.17, 0.99], p = 0.048. Patients with combination of partial-support mAFP and VA-ECLS had a higher mortality risk than all other patients, HR 2.06 [95% CI: 1.16, 3.36], p = 0.013. Conclusions: In patients with partial-support mAFP and concomitant VA-ECLS, an escalation to a full-support mAFP may translate to improved survival and should be considered to facilitate VA-ECLS weaning.