Cardiac power output index to define hemodynamic response to Impella support in cardiogenic shock

Early assessment of response to Impella in cardiogenic shock may guide escalation of mechanical circulatory support. Therapeutic goal and response to Impella have not previously been defined. This study tested the hypothesis that targeting 3-h post- Impella cardiac power output index (CPOi)-"hemodynamic response"-in cardiogenic shock is associated with 12-h lactate clearance.

Single-center study of 37 consecutive patients who underwent left-sided Impella support for cardiogenic shock due to either acute myocardial infarction or decompensated heart failure. Patients who achieved 3-h post-Impella CPOi ⩾ 0.30 W/m² were defined as Impella "hemodynamic responder."

Twelve of the thirty-seven patients achieved 3-h post-impella CPOi  ⩾ 0.30 W/m² ("hemodynamic responders"). Post-Impella CPOi correlated with 12-h lactate (r = -0.779, p < 0.001) and lactate clearance (r = 0.747, p < 0.001). "Hemodynamic responders" had lower 12-h lactate level and greater 12-h lactate clearance (52 (44-58) vs 17 (14-26)%, p < 0.001). Higher pre-Impella norepinephrine dose (-0.341, p = 0.003) and baseline lactate (-0.009, p = 0.003) were independently associated with lower 3-h post-Impella CPOi. Eighteen patients died within 30 days (2/12 "hemodynamic responders" compared to 16/25 "non-responders," p < 0.001).

Patients who achieved early 3-h post-Impella CPOi of ⩾0.30 W/m² have greater lactate clearance and better short-term survival. Early post-Impella CPOi of 0.30 W/m² may be used as a therapeutic goal and define favorable response to Impella in cardiogenic shock.