SCAI Releases Updated Shock Classification Statement

Srihari S. Naidu, MD

The Society for Cardiovascular Angiography and Interventions (SCAI) has released an updated consensus statement for the classification of cardiogenic shock.

The statement, which is an update to their first shock classification document released in 2019, has received endorsement from multiple other organizations, including the American College of Cardiology, American College of Emergency Physicians, American Heart Association, European Society of Cardiology, and more.

“The new updated definition is easier to use, with tables that have eliminated relatively unnecessary variables and highlighted the more commonly present ones in each shock stage, a more useful cardiac arrest modifier, and a 3-axis model that places the shock stages in context of other variables that need to be considered for the patient in front of you,” said writing group chair Srihari S. Naidu, MD, director of the Cardiac Catheterization Laboratory at Westchester Medical Center and SCAI Trustee, in a statement from the SCAI.

Since the release of the original statement in 2019, new studies have added to the existing knowledge base related to management and outcomes of patients with cardiogenic shock. Composed by Naidu and a team of 15 coauthors, the updated statement is 11 pages in length and cites 34 reference documents.

With the aim of improving the classification model, authors incorporated a more comprehensive model leveraging data related to predictors of mortality and nonmodifiable risk factors. Authors also intended to provide more granularity to the cardiac arrest modifiers and the constituent domains of classification as well as allow for gradations of risk within each SCAI SHOCK stage.

“Cardiac arrest remains an important predictor of mortality in patients with cardiogenic shock, but we clarify the risk is in patients with unclear neurogenic status,” said statement vice-chair Timothy Henry, MD, president of SCAI.

The statement is broken down into sections, with the 3 largest sections dedicated to a review of published SCAI SHOCK stage validation studies, lessons learned from the validation studies, and the updated classification pyramid and table. The authors also dedicated a portion of the document to provide perspective on future considerations and research.

In the section dedicated to future considerations and research, authors suggest incorporation of shock stage classification system as a risk marker of acuity, as inclusion or exclusion criteria, or to stratify interventions across shock stages could improve cardiogenic shock registries and clinical trials. Authors also note the SCAI SHOCK is designed to be applied through all phases of care, but more work is required to understand optimal reassessments intervals and associations between mortality risk and temporal changes in shock stages from presentation through deterioration and recovery, destination therapy, or palliation.

“We have made it much clearer how patients move up and down the stages if they deteriorate or recover, what these changes do to survival, and how support strategies such as mechanical support devices or vasopressors tie into the various stages,” Naidu added.

This statement, “SCAI SHOCK Stage Classification Expert Consensus Update: A Review and Incorporation of Validation Studies,” was simultaneously published in the Journal of the Society for Cardiovascular Angiography & Interventions and the Journal of the American College of Cardiology.