Intra-Aortic Balloon Pump

Intra-Aortic Balloon Pump (IABP) counterpulsation is the most widely used mechanical circulatory devices in cardiogenic shock.

Physiology of IABP counterpulsation

  • The device inflates and deflates in concert with the cardiac cycle, increasing the diastolic blood pressure and reducing the systolic blood pressure
  • Balloon deflation provides a rapid, synchronized reduction in impedance (afterload) during isovolemic LV contraction
  • Balloon inflation provides a rapid, synchronized increase in aortic pressure during isovolemic LV relaxation (diastolic augmentation)
  • Combination of balloon deflation and inflation leads to
    • LV systolic unloading
      • reduced stroke work
      • reduced myocardial O2 consumption
    • Diastolic augmentation
      • raises arterial blood pressure
      • provides better coronary arterial perfusion during diastole
      • increased myocardial O2 delivery
  • Myocardial recovery is achieved thanks to the reduction of cardiac work and the simultaneous increase in myocardial O2 supply
  • Success is dependent on the patient having a minimum degree of LV function that in combination with IAPB achieve an adequate cardiac output
  • When minimal CO is not met alternative MCS must be considered

Indications for IABP

  • Absolute indications for IABP as a primary therapy
    • cardiogenic shock
    • uncontrolled angina pectoris
    • acute postinfarction ventricular septal defect (VSD)
    • postinfarction mitral regurgitation (MR) secondary to papillary muscle rupture
    • postcardiotomy left-sided HF with low cardiac output
  • Relative indications include
    • high-risk, catheter-based interventional procedures (LMCA angioplasty)
    • after unsuccessful attempts at catheter-based intervention in patients with poorly controlled ventricular arrhythmias and poor LV function
    • stunned ischemic myocardium
  • Relative contraindications
    • severe atheromatous disease of the descending thoracic aorta
    • descending aortic dissection or aneurysm
    • recent descending thoracic aortic surgery
    • mild to moderate aortic insufficiency
  • Absolute contraindications
    • severe aortic insufficiency: diastolic augmentation cannot be accomplished and LV end-diastolic volume and pressure are increased and not decreased

Insertion of IABP

  • made of a polyurethane membrane mounted on a vascular 7F or 8F catheter
  • percutaneous (Seldinger technique) or by surgical cutdown in the common femoral artery
  • tip positioned just distal to the takeoff of the left subclavian artery in the proximal descending thoracic aorta
  • positioned with TEE or fluoroscopy guidance

Evidences

IABP-SHOCK II Trial (2012)

  • enrolled patients with cardiogenic shock after myocardial infarction
  • no difference in the primary endpoint of 30-day mortality, prespecified secondary endpoints or 1-year outcome between those with and those without IABP support
  • this results downgraded IABP from Class I (before 2012) to Class IIIA recommendation for routine use in cardiogenic shock in the most recent European revascularization and non–ST-segment–elevation ACS guidelines
  • IABP use rates have subsequently declined

Registry studies have reported only minimal improvement in MAP, CI, serum lactate, and catecholamine requirements with IABP counterpulsation

References

Chris C. Cook and Thomas G. Gleason. Mechanical Support in Cardiogenic Shock. Textbook of Critical Care (2017)

Thiele H, Zeymer U, Neumann FJ, et al. Intraaortic balloon support for myocardial infarction with cardiogenic shock. N Engl J Med. 2012;367(14):1287‐1296. doi:10.1056/NEJMoa1208410