New guidelines redefine cardiogenic shock

An expert consensus document endorsed by four major cardiology societies redefines cardiogenic shock based on patient descriptions, physical markers and a standardized set of vocabulary.

Published in Catheterization and Cardiovascular Interventions during this year’s Society for Cardiovascular Angiography and Interventions (SCAI) meeting in Las Vegas, the new definition takes a five-step approach to cardiogenic shock diagnosis. According to a statement from SCAI, outcomes for cardiogenic shock—especially shock accompanying MI—haven’t improved in three decades.

SCAI convened a multidisciplinary writing group of industry experts in interventional and advanced heart failure, noninvasive cardiology, emergency medicine and critical care to outline the best practices for treating patients with cardiogenic shock. Right now the national standard is emergent angioplasty and stenting, but physicians across the U.S. are working on different wavelengths.

“The main areas we may have failed in the fight to improve mortality in cardiogenic shock is, quite simply, not speaking the same language when describing these patients,” Srihari S. Naidu, MD, chair of the writing group, said in the release. “Without that, we can’t even begin to understand these patients, how sick they are, what might work and what does not work. This is the most important first step and it is important to use this classification system to reset our understanding of cardiogenic shock and restart the trials very much needed in this space.”

The system takes the form of a lettered five-section pyramid, where A—the broad “at-risk” subgroup—makes up the base of the pyramid and E—the smaller “extreme” subgroup—sits at the top. Naidu and his team created a comprehensive chart that details the biochemical markers, hemodynamics and physical symptoms that accompany each level.

At-risk patients were characterized by normal jugular venous pressure (JVP), clear lung sounds, strong distal pulses and normal mentation, as well as normal renal function, lactic acid and hemodynamics. Symptoms continue to get more dire as the pyramid narrows, eventually reaching a state of near-pulselessness, cardiac collapse and uncontrolled hypotension in the most extreme cases.

In brief, these are the writing group’s five stages of cardiogenic shock:

  • A (At-risk): The patient has risk factors for cardiogenic shock but isn’t experiencing any signs or symptoms.
  • B (Beginning): The patient has clinical evidence of relative hypotension or tachycardia without hypoperfusion and has elevated JVP, strong distal pulses and normal mentation. Lactate is normal, with minimal renal function impairment and elevated BNP.
  • C (Classic): The patient presents with hypoperfusion that requires intervention beyond resuscitation. They look ashen, need mechanical ventilation, may see acute alteration in their mental status and exhibit elevated BNP, doubled creatinine and higher lactate.
  • D (Deteriorating): The patient fails to respond to initial interventions. Most of the symptoms are the same as stage C, with the addition of deterioration.
  • E (Extremis): The patient is supported by multiple interventions but isn’t responding to them. This stage is characterized by cardiac collapse, high lactate, no SBP without resuscitation and hypotension.

The American College of Cardiology, American Heart Association, Society of Critical Care Medicine and the Society of Thoracic Surgeons all endorsed the guidelines, which can be found in full here.