Hemolysis is a recognized complication of mechanical circulatory support and may contribute to acute kidney injury in patients with cardiogenic shock. Early hemolysis during Impella support, particularly compared with intra‐aortic balloon pump (IABP), remains incompletely characterized.

We retrospectively analyzed a single‐center registry of consecutive patients with cardiogenic shock treated with IABP or Impella between August 2022 and October 2024. Serum haptoglobin was measured at intensive care unit admission and every 12 hours during device support. Low haptoglobin was defined as <19 mg/dL.

Among 91 patients (IABP, n=67; Impella CP, n=24), baseline haptoglobin levels were similar. Patients supported with Impella exhibited a significantly greater decline in haptoglobin beginning 12 hours after intensive care unit admission, particularly in the absence of concomitant venoarterial extracorporeal membrane oxygenation. Low haptoglobin occurred more frequently with Impella than with IABP (67% versus 31%, P=0.004), whereas the incidence of overt clinical hemolysis was low and comparable between devices. Impella use (odds ratio, 2.82 [95% CI, 1.45–5.95]; P=0.001), concomitant venoarterial extracorporeal membrane oxygenation support (odds ratio, 16.52 [95% CI, 4.65–174.56]; P<0.001), and lower mean arterial pressure at intensive care unit admission (OR, 0.95 [95% CI, 0.89–0.99]; P=0.006) were independently associated with low haptoglobin.

In patients with cardiogenic shock, Impella CP support was associated with earlier and more frequent decline in serum haptoglobin compared with IABP, suggesting more frequent subclinical hemolysis. Although overt hemolysis was uncommon, early monitoring using serial serum haptoglobin measurements may help inform device management strategies.