What are the SCAI (Society for Cardiovascular Angiography and Interventions) guidelines for managing patients with cardiogenic shock undergoing percutaneous coronary intervention (PCI)?

SCAI Guidelines for Managing Patients with Cardiogenic Shock Undergoing PCI

Primary PCI is strongly recommended for patients with acute myocardial infarction who develop cardiogenic shock and are suitable candidates, as it is the only treatment proven to decrease mortality rates. 1

Patient Selection for Revascularization

• Class I recommendation (Level of Evidence: B):

  • PCI for patients with acute MI who develop cardiogenic shock and are suitable candidates 1
  • Particularly beneficial for patients <75 years old with ST elevation or left bundle-branch block who develop shock within 36 hours of MI 1
  • Revascularization should be performed within 18 hours of shock onset 1

• Class IIa recommendation (Level of Evidence: B):

  • PCI is reasonable for selected patients ≥75 years with good prior functional status who develop shock within 36 hours of MI 1

Hemodynamic Support

• Class I recommendation (Level of Evidence: B):
  • A hemodynamic support device is recommended for patients with cardiogenic shock after STEMI who do not quickly stabilize with pharmacological therapy 1
  • Options include intra-aortic balloon pump (IABP) counterpulsation or percutaneous LV assist devices 1
  • Early implementation is recommended in patients with profound shock unlikely to reverse with culprit lesion PCI alone 2

Initial Management Protocol

1. Pharmacological Therapy:

   • Standard therapies including aspirin, P2Y12 receptor antagonist, and anticoagulation 1
   • Inotropic and vasopressor therapy to improve perfusion pressure 1
   • Avoid negative inotropes and vasodilators 1

2. Respiratory and Cardiac Support:

   • Endotracheal intubation and mechanical ventilation with positive end-expiratory pressure for respiratory failure 1
   • Temporary pacemaker placement for bradycardia or high-degree AV block 1
   • Pulmonary artery catheter to guide inotrope and pressor dosing 1

3. Procedural Considerations:

   • Minimize contrast medium injections 1
   • Orthogonal angiograms of left coronary artery and left anterior oblique angiogram of right coronary artery are usually sufficient to identify the infarct artery 1

Revascularization Strategy

• Culprit Lesion Approach:

  • PCI of the culprit lesion only, with the option of staged revascularization of non-culprit lesions, is associated with lower 30-day risk of death or severe renal failure compared to immediate multivessel PCI 3

• Multivessel Disease Considerations:

  • In patients with multivessel disease, consider emergency CABG for severe 3-vessel or left main disease 1
  • Mortality increases with the number of diseased vessels (from 34.2% with single-vessel disease to 51.2% with 3-vessel disease) 4

• Stent Selection:

  • Bare metal stents (BMS) are often used because compliance with long-term dual antiplatelet therapy (DAPT) is often unclear in emergency settings 1
  • Conflicting data exists on stenting versus balloon angioplasty in shock patients 1

Prognostic Factors

• Predictors of Mortality:

  • Increasing age 5
  • Lower systolic blood pressure 5
  • Increasing time from randomization to PCI 5
  • Lower post-PCI TIMI flow (TIMI 0/1 vs 2/3) 5, 4
  • Multivessel PCI 5
  • Presence of severe mitral regurgitation 5

• Importance of Coronary Flow:

  • Mortality is 38% if TIMI flow grade 3 is achieved, 55% with TIMI grade 2 flow, and approaches 100% with TIMI grade 0/1 flow 5
  • Successful PCI reduces mortality to 39% compared to 85% with unsuccessful PCI 5

Implementation Considerations

• Patients presenting to hospitals without PCI capability should be emergently transported to a PCI center 1
• Despite guideline recommendations since 1999, implementation has been suboptimal, highlighting the need for increased adherence 6
• Revascularization attempts may be futile and not indicated in cases of severe multiorgan failure 1

Caveat

While early revascularization has significantly improved outcomes, in-hospital mortality remains high (decreased from 60.3% in 1995 to 47.9% in 2004) even with successful PCI 6, emphasizing the need for comprehensive care beyond revascularization.