Preemptive Transvalvular Mechanical Circulatory Support is Safe and Feasible in High-Risk Cardiac Surgery Patients: Results of IMPACT.

Abstract

To assess the safety and feasibility of Impella 5.5-protected cardiac surgery in patients with severe left ventricular dysfunction. IMPACT is a prospective, multicenter, single-arm study assessing the safety and feasibility of initiation of transvalvular left ventricular unloading prior to separation from cardiopulmonary bypass. Eligible patients had a reduced left ventricular ejection fraction with planned elective or urgent conventional cardiac surgery. Patients were supported with the Impella 5.5 for at least 24 hours post-operation. Key exclusion criteria included pre-operative inotropic or mechanical circulatory support. A clinical events committee adjudicated endpoint events. One hundred subjects were enrolled at 18 sites in the United States, all of whom successfully received the Impella 5.5. Baseline left ventricular ejection fraction was 25% (IQR: 21.6, 28.9%) and STS-PROM was 4.1% (IQR: 2.5, 7.1%). The index cardiac procedure was primarily isolated coronary artery bypass graft (56%) or coronary artery bypass graft+valve (35%). Post-cardiotomy cardiac failure through hospital discharge, the primary effectiveness endpoint, occurred in 6% of subjects. The composite of all-cause mortality, stroke and new requirement for renal replacement therapy through 90 days post-operation, primary safety endpoint, occurred in 12% of subjects. The 30- and 90-day mortality were 2% and 4%, respectively. Subjects had a favorable post-operative trajectory with low perioperative VIS (VIS_max <10 within 24 hours post-operation), timely extubation (14.4 hours) and acceptable hospital length of stay (13.9 days). Impella 5.5-protected cardiac surgery appears safe, feasible and is a promising device supported strategy for cardiac surgery patients with severe left ventricular dysfunction.