SCAI shock classification system predictive of mortality in cardiogenic shock
The SCAI shock classification system may provide mortality risk stratification of patients at risk for or who experienced cardiogenic shock, a speaker reported.
According to data presented at the virtual Society for Cardiovascular Angiography and Interventions Scientific Sessions, mortality risk in cardiogenic shock was modifiable by factors including older age and rising SCAI stage at 24 hours.
“We wanted to look at whether the recently published SCAI shock classification was able to provide mortality risk stratification, the presumption here being that patients with a greater severity of shock would be sicker and therefore more likely to die,” Jacob Jentzer, MD, critical care specialist at Mayo Clinic, said during the presentation. Because the SCAI shock classification was developed based on expert consensus rather than a data-driven approach, it was important to see whether this hypothesis was testable in reality.”
In a previous consensus statement published in Catheterization and Cardiovascular Interventions (Baran DA, et al. Catheter Cardiovasc Interv. 2019;doi:10.1002/ccd.28329), SCAI proposed an alphabetical system for describing stages of cardiogenic shock:
- stage A is “at risk” for cardiogenic shock;
- stage B is “beginning” shock;
- stage C is “classic” cardiogenic shock;
- stage D is “deteriorating;” and
- stage E is “extremis.”
According to the consensus statement, hypoperfusion is present in stages C and higher; stage D implies that the initial intervention has not restored stability and adequate perfusion; and in stage E the patient is highly unstable, often with CV collapse.
The cardiogenic shock consensus statement was endorsed by the American College of Cardiology, the American Heart Association, the Society of Critical Care Medicine and the Society of Thoracic Surgeons in April 2019.
For this analysis, researchers reviewed 15 studies that included more than 15,000 critically ill patients (one prospective; no randomized trials) that assessed seven separate definitions of the SCAI shock stages. The goal of this study was to determine if the SCAI shock stages provided any utility for mortality risk stratification.
Overall, the prevalence of the SCAI cardiogenic shock stages were as follows: A, 0% to 46%; B, 0% to 41%; C, 13% to 61%; D, 7% to 55%; and E, 1% to 31%.
According to the presentation, each study demonstrated a stepwise increase of 30-day in-hospital mortality for each higher SCAI shock stage (A, 1% to 5%; B, 0% to 34%; C, 11% to 54%; D, 24% to 68%; E, 42% to 77%). This observation was consistent in all subgroups.
For every SCAI cardiogenic shock stage, factors such as cardiac arrest, older age, rising SCAI stage at 24 hours, poor hemodynamics, abnormal echocardiography, systemic inflammation and acute kidney injury were associated with lower observed survival.
“Regardless of the definition that was used, the SCAI shock classification was able to provide mortality risk stratification in essentially every group of patients where it's been studied,” Jentzer said during the presentation. “Although the risk for mortality was higher at each higher shock stage, we found that this mortality risk could be modified by numerous variables as well as the population that was being studied. We're using information gleaned from this research to help us better inform an updated SCAI shock classification that we're hoping to present this fall at the SCAI Shock 2021 meeting.”
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Jentzer JC, et al. Featured Clinical Research: Acute coronary and cardiogenic shock. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; April 28-May 1, 2021 (virtual meeting).
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