New — SCAI Shock Staging
Q86 / 110
A patient with acute anterior STEMI has SBP 82 mmHg and tachycardia, but no clinical signs of end-organ hypoperfusion. Which SCAI shock stage best describes this presentation?
Correct answer: B — Stage B — Beginning (pre-shock)
SCAI stage B ("Beginning") describes a patient with hemodynamic instability — hypotension or tachycardia — but without clinical evidence of hypoperfusion. Stage A is reserved for patients at risk for shock but without any hemodynamic abnormality. Stage C requires evidence of hypoperfusion (e.g., elevated lactate, renal dysfunction, altered mental status), either untreated or requiring pharmacologic or mechanical intervention. Stage D requires failure of an initial intervention with need for escalation.
Board pearl: The key distinction between SCAI B and C is the presence or absence of end-organ hypoperfusion, not hypotension alone.
SCAI stage B ("Beginning") describes a patient with hemodynamic instability — hypotension or tachycardia — but without clinical evidence of hypoperfusion. Stage A is reserved for patients at risk for shock but without any hemodynamic abnormality. Stage C requires evidence of hypoperfusion (e.g., elevated lactate, renal dysfunction, altered mental status), either untreated or requiring pharmacologic or mechanical intervention. Stage D requires failure of an initial intervention with need for escalation.
Board pearl: The key distinction between SCAI B and C is the presence or absence of end-organ hypoperfusion, not hypotension alone.
Source(s): Baran DA, Grines CL, Bailey S, et al. SCAI Clinical Expert Consensus Statement on the Classification of Cardiogenic Shock. Catheter Cardiovasc Interv. 2019;94(1):29-37. doi:10.1002/ccd.28329. | Naidu SS, Baran DA, Jentzer JC, et al. SCAI SHOCK Stage Classification Expert Consensus Update. J Am Coll Cardiol. 2022;79(9):933-946. doi:10.1016/j.jacc.2022.01.018.
Q87 / 110
Which statement best describes the prognostic value of the SCAI shock classification?
Correct answer: B — Hospital mortality increases in a stepwise fashion from stage A (~3%) to stage E (~67%)
In the initial validation by Jentzer et al. of 10,004 CICU patients, hospital mortality rose from approximately 3.0% in stage A to 7.1% in B, 12.4% in C, 40.4% in D, and 67.0% in stage E. This stepwise relationship was consistent across patients with ACS, heart failure, and other etiologies of shock. Cardiac arrest at any stage independently increased mortality (adjusted OR 3.99). The Cardiogenic Shock Working Group (CSWG) registry, using refined criteria, confirmed a similar gradient: roughly 14.3% (B), 20.9% (C), 32.7% (D), and 44.8% (E).
Board pearl: SCAI staging predicts mortality across all cardiogenic shock etiologies, not just AMI.
In the initial validation by Jentzer et al. of 10,004 CICU patients, hospital mortality rose from approximately 3.0% in stage A to 7.1% in B, 12.4% in C, 40.4% in D, and 67.0% in stage E. This stepwise relationship was consistent across patients with ACS, heart failure, and other etiologies of shock. Cardiac arrest at any stage independently increased mortality (adjusted OR 3.99). The Cardiogenic Shock Working Group (CSWG) registry, using refined criteria, confirmed a similar gradient: roughly 14.3% (B), 20.9% (C), 32.7% (D), and 44.8% (E).
Board pearl: SCAI staging predicts mortality across all cardiogenic shock etiologies, not just AMI.
Source(s): Jentzer JC, van Diepen S, Barsness GW, et al. Cardiogenic Shock Classification To Predict Mortality in the Cardiac Intensive Care Unit. J Am Coll Cardiol. 2019;74(17):2117-2128. doi:10.1016/j.jacc.2019.07.077. | Scott M, Kyriakopoulos CP, Sheffield E, et al. Application of the Updated Cardiogenic Shock Working Group SCAI Classification for Cardiogenic Shock. Can J Cardiol. 2025. doi:10.1016/j.cjca.2025.03.036.
Q88 / 110
A patient with STEMI-related cardiogenic shock is started on norepinephrine and an Impella CP. After 6 hours, lactate rises from 3.2 to 7.8 mmol/L, ALT increases to 620 U/L, and a second vasopressor is added. Which SCAI stage transition has occurred, and what does it imply?
Correct answer: B — Stage C to D — consider escalation of mechanical circulatory support
This patient has transitioned from SCAI stage C to D. Stage C is defined by hypoperfusion requiring intervention (one drug or one device). Stage D is defined by failure of initial therapy with worsening hypoperfusion (lactate 5–10 mmol/L or ALT >500 U/L) and the need for two to five drugs or devices. The 2022 SCAI update emphasizes that stage D represents the failure of an adequate trial of an initial supportive intervention and should prompt consideration of escalation. The AHA scientific statement on tMCS escalation recommends that if a patient is undersupported on their present device, escalation to a higher level of MCS should be considered.
Board pearl: Stage D is defined by failure of initial therapy — it requires time and an adequate trial of intervention, distinguishing it from stage C.
This patient has transitioned from SCAI stage C to D. Stage C is defined by hypoperfusion requiring intervention (one drug or one device). Stage D is defined by failure of initial therapy with worsening hypoperfusion (lactate 5–10 mmol/L or ALT >500 U/L) and the need for two to five drugs or devices. The 2022 SCAI update emphasizes that stage D represents the failure of an adequate trial of an initial supportive intervention and should prompt consideration of escalation. The AHA scientific statement on tMCS escalation recommends that if a patient is undersupported on their present device, escalation to a higher level of MCS should be considered.
Board pearl: Stage D is defined by failure of initial therapy — it requires time and an adequate trial of intervention, distinguishing it from stage C.
Source(s): Kapur NK, Kanwar M, Sinha SS, et al. Criteria for Defining Stages of Cardiogenic Shock Severity. J Am Coll Cardiol. 2022;80(3):185-198. doi:10.1016/j.jacc.2022.04.049. | Geller BJ, Sinha SS, Kapur NK, et al. Escalating and De-Escalating Temporary Mechanical Circulatory Support in Cardiogenic Shock: A Scientific Statement From the AHA. Circulation. 2022;146(6):e50-e68. doi:10.1161/CIR.0000000000001076.
Q89 / 110
A patient presents in SCAI stage C cardiogenic shock. At 24 hours, despite Impella CP and one vasopressor, the patient has progressed to stage D. Which statement best reflects the prognostic significance of this trajectory?
Correct answer: B — Patients who progress from any stage to stage E at 24 hours have mortality exceeding 60%
The CSWG serial assessment study by Ton et al. demonstrated that shock trajectory is independently prognostic. Patients who progressed from any baseline stage to stage E at 24 hours had mortality rates of 62–80% (from B: 71.4%, from C: 80%, from D: 62.2%). Conversely, patients who improved from stage D to a lower stage at 24 hours had substantially lower mortality (13.7%). The 2022 SCAI update emphasizes that patient trajectories are important both for communication among clinicians and for decision-making regarding the next level of care and therapeutics, supporting the AHA recommendation for daily reassessment of readiness to escalate or wean tMCS.
Board pearl: Shock trajectory — whether a patient is improving, stable, or deteriorating — is as prognostically important as the baseline SCAI stage itself.
The CSWG serial assessment study by Ton et al. demonstrated that shock trajectory is independently prognostic. Patients who progressed from any baseline stage to stage E at 24 hours had mortality rates of 62–80% (from B: 71.4%, from C: 80%, from D: 62.2%). Conversely, patients who improved from stage D to a lower stage at 24 hours had substantially lower mortality (13.7%). The 2022 SCAI update emphasizes that patient trajectories are important both for communication among clinicians and for decision-making regarding the next level of care and therapeutics, supporting the AHA recommendation for daily reassessment of readiness to escalate or wean tMCS.
Board pearl: Shock trajectory — whether a patient is improving, stable, or deteriorating — is as prognostically important as the baseline SCAI stage itself.
Source(s): Ton VK, Li S, John K, et al. Serial Shock Severity Assessment Within 72 Hours After Diagnosis: A Cardiogenic Shock Working Group Report. J Am Coll Cardiol. 2024. doi:10.1016/j.jacc.2024.04.069. | Naidu SS, Baran DA, Jentzer JC, et al. SCAI SHOCK Stage Classification Expert Consensus Update. J Am Coll Cardiol. 2022;79(9):933-946. doi:10.1016/j.jacc.2022.01.018.
Q90 / 110
A patient in SCAI stage C cardiogenic shock has LV-predominant failure with adequate oxygenation and mild RV dysfunction. Which initial tMCS strategy best matches the phenotype and severity?
Correct answer: B — Impella CP or 5.5
Contemporary frameworks recommend matching tMCS to both SCAI stage severity and ventricular phenotype (LV-dominant, RV-dominant, or biventricular). For LV-predominant stage C shock with adequate oxygenation, the AHA scientific statement suggests initial support with IABP, LV Impella, or TandemHeart, with more severe shock favoring Impella 5.5 over Impella CP. VA-ECMO is reserved for patients with significant concomitant RV dysfunction, hypoxemia, or more severe shock. Protek Duo supports the RV, not the LV. Total artificial heart is premature at this stage.
Board pearl: Device selection in cardiogenic shock requires matching both the SCAI severity stage and the ventricular failure phenotype — LV-dominant, RV-dominant, or biventricular.
Contemporary frameworks recommend matching tMCS to both SCAI stage severity and ventricular phenotype (LV-dominant, RV-dominant, or biventricular). For LV-predominant stage C shock with adequate oxygenation, the AHA scientific statement suggests initial support with IABP, LV Impella, or TandemHeart, with more severe shock favoring Impella 5.5 over Impella CP. VA-ECMO is reserved for patients with significant concomitant RV dysfunction, hypoxemia, or more severe shock. Protek Duo supports the RV, not the LV. Total artificial heart is premature at this stage.
Board pearl: Device selection in cardiogenic shock requires matching both the SCAI severity stage and the ventricular failure phenotype — LV-dominant, RV-dominant, or biventricular.
Source(s): Narang N, Blumer V, Jumean MF, et al. Management of Heart Failure-Related Cardiogenic Shock: Practical Guidance for Clinicians. JACC Heart Fail. 2023;11(7):845-851. doi:10.1016/j.jchf.2023.04.010. | Geller BJ, Sinha SS, Kapur NK, et al. Escalating and De-Escalating Temporary Mechanical Circulatory Support in Cardiogenic Shock. Circulation. 2022;146(6):e50-e68. doi:10.1161/CIR.0000000000001076.