The goal of this multicenter, randomized trial is to compare early early left ventricular unloading by Intra-aortic Balloon Pump (IABP) versus conventional approach in patients with cardiogenic shock (CS) undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO). The main question it aims to answer is :

• If left ventricular unloading by IABP as compared with the conventional approach will improve the outcomes in patients undergoing VA-ECMO.

The role of IABP combined with VA-ECMO in patients with CS remains unclear. Therefore, investigators will conduct a prospective randomized clinical trial to explore the effect of early IABP use for LV unloading after VA-ECMO on outcomes in patients with CS. Investigators will randomly assign 358 patients receiving peripheral VA-ECMO to the ECMO+IABP group (n=179) or the ECMO group (n=179). The primary end point was the 30-day mortality.

Inclusion Criteria:

1. Age of ≥18
2. Cardiogenic shock(defined as a systolic blood pressure of less than 90 mm Hg for more than 30 minutes or the initiation of catecholamines to maintain a systolic pressure of more than 90 mm Hg, an arterial lactate level of more than 3 mmol per liter, and signs of impaired organ perfusion)
3. Successful implantation of VA-ECMO
4. Informed consent

Exclusion Criteria:

1. SCAI shock stage A or B
2. Presence of moderate to severe aortic insufficiency or aortic dissection
3. Severe peripheral vascular disease
4. Post-cardiotomy cardiogenic shock(non-CABG procedure) or bridging to cardiac procedure(heart transplantation or LVAD).
5. VA-ECMO for definite non-cardiac causes
6. Isolated right ventricular failure
7. V-A ECMO usage confined to the period during surgery or other interventions
8. Ischemic mechanical complications(eg Ventricular septal defect, papillary muscle rupture)
9. Extracorporeal cardiopulmonary resuscitation
10. LVAD, Impella or IABP in situ.
11. Severe bleeding
12. Terminal malignancy
13. Irreversible neurologic injury
14. Pregnancy or lactation