03-07-2025
Microaxial Flow Pump Reduces Heart Load in Post-MI Shock
TOPLINE:
In patients with ST-segment elevation myocardial infarction (STEMI)-induced cardiogenic shock undergoing hemodynamic monitoring with a pulmonary artery catheter, the use of a microaxial flow pump (mAFP; Impella) reduced the intrinsic mechanical work performed by the heart by reducing native cardiac output and pulmonary pressures while maintaining the power output delivered to the body.
METHODOLOGY:
A previous Danish-German trial showed reduced mortality with early placement of an mAFP in patients with cardiogenic shock following STEMI.
In this substudy, researchers analyzed data of 223 patients monitored in the cardiac ICU with a pulmonary artery catheter to determine the effects of the device on hemodynamics in STEMI-induced cardiogenic shock.
Patients had been randomly assigned to receive either standard care (n = 98; median age, 67 years; 78% men) or an mAFP plus standard care (n = 125; median age, 65 years; 82% men).
Outcomes included cardiac output, mean pulmonary artery pressure, and cardiac power output during the first 48 hours after admission to the cardiac ICU; native cardiac output was defined as the patient's total cardiac output minus the estimated mAFP flow.
TAKEAWAY:
After the initial 6 hours in the cardiac ICU, cardiac output continued to improve in the mAFP group and remained consistently higher than in the standard care group from 12 to 48 hours (P < .001). Native cardiac output also improved after 6 hours but stayed significantly lower in the mAFP group than in the standard care group.
Mean pulmonary artery pressure was initially lower in the mAFP group than in the standard care group (median, 27 vs 31 mm Hg; P < .001) and remained lower at 48 hours. Pulmonary capillary wedge pressure was also lower in the patients with an mAFP.
The initial cardiac power output within 3 hours of arrival to the cardiac ICU was 0.56 W in the standard care group vs 0.68 W in the mAFP group (P = .01), which improved over the next 48 hours.
The mAFP group required lesser vasoactive and inotropic support than the standard care group for the first 6 hours and had lower mortality at 180 days.
IN PRACTICE:
'We consistently found lower pulmonary pressures and a PCWP [pulmonary capillary wedge pressure] during mAFP support, each of which provides confirmation of LV [left ventricular] unloading while on mAFP. Reducing these pressures helps alleviate pulmonary edema, reduce right ventricular afterload, and enhance forward flow,' the researchers wrote.
'By reducing myocardial work and wall stress, unloading may be protective in stunned, postischemic myocardium vulnerable to further insult,' the authors of an editorial accompanying the journal article wrote.
SOURCE:
This study was led by Jacob Eifer Møller, MD, DMSc, Odense University Hospital, Odense, Denmark. It was published online on June 23, 2025, in Journal of the American College of Cardiology.
LIMITATIONS:
Pulmonary artery catheter was used more frequently in patients randomized to the mAFP group compared with the standard care group. Data capture may not have been streamlined or complete as this study involved patients who were critically ill, unstable, and had imminent need for treatment. Hemodynamic monitoring was limited to the first 48 hours and did not account for long-term effects or changes.
DISCLOSURES:
The original trial was supported by the Danish Heart Foundation and Abiomed. Several authors reported receiving research, educational, and/or travel grants, speaker fees, and honoraria; serving on advisory boards; holding stock options; and having other financial ties with various pharmaceutical, healthcare, and other companies, including Abiomed, Novo Nordisk Foundation, and Boston Scientific.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
