#cardiogenic-shock #heart-failure #acute-myocardial-infarction #hemodynamic-monitoring #mechanical-circulatory-support

Cardiogenic Shock

Definition

A cardiac disorder that results in both clinical and biochemical evidence of sustained tissue hypoperfusion, irrespective of blood pressure. CS is one of the most common causes of admission to contemporary cardiac ICUs, carrying 30–40% short-term mortality and ~50% 1-year mortality.

Key Concepts

Epidemiology

Short-term (in-hospital) mortality 30–40%; 1-year mortality approaching or exceeding 50% sources/cardiogenic-shock-acc-2025 (very high)
In-hospital mortality of AMI-CS (Killip IV) fell from 62.2% (1997) → 36.3% (2017) in Swiss AMI registry over 20 years sources/mcs-jic-2023 (high)
Tokyo CV Care Unit Network: in-hospital mortality 38.5% (2007) → 27.2% (2016) in AMI-CS — similar trend in Japan sources/mcs-jic-2023 (high)
Japanese DPC database (n=160,559; 2010–2020): IABP-alone use fell 80.5% → 65.3%; Impella rose 0% → 5.0%; ECMO 19.5% → 29.6% — tMCS landscape shifting toward more powerful devices sources/mcs-jic-2023 (high)
Non-infarction CS now outnumbers AMI-CS in contemporary registries — epidemiological shift from improved MI prevention/revascularization sources/cardiogenic-shock-nejm-2026 (very high)
71% of AMI-CS patients have frailty — major prognostic factor sources/cardiogenic-shock-nejm-2026 (very high)
Mortality by etiology (SHARC registry; n=8,974): mixed CS 48% > AMI-CS 41% > new HF-CS 31% = secondary CS 31% > acute-on-chronic HF-CS 25% sources/cardiogenic-shock-nejm-2026 (very high)
Cause of death: persistent shock (dominant) > arrhythmia > anoxic brain injury > respiratory failure
AMI-CS has historically predominated in RCTs; HF-CS is increasing in prevalence over the past decade in the US
Notable differences in baseline characteristics, comorbidities, resource utilization, and outcomes between AMI-CS and HF-CS

Phenotypes / Etiologies (Shock Academic Research Consortium)

AMI-CS: CS due to AMI (STEMI or non-STEMI); includes LV, RV, or biventricular dysfunction; mechanical complications of MI; arrhythmias and advanced heart block in setting of AMI
HF-CS: CS from primary myocardial dysfunction (ischemic or non-ischemic cardiomyopathy); de novo HF-CS vs acute-on-chronic HF-CS; subtypes include myocarditis, takotsubo, peripartum, tachycardia-related cardiomyopathy, HCM, cardiac amyloidosis, sarcoidosis
Postcardiotomy CS: after cardiac surgery
Secondary CS: arrhythmias, valvular disease, pericardial disease, other etiologies
Mixed shock: cardiogenic shock with ≥1 additional concurrent cause (e.g., septic, hypovolemic); highest mortality (48%) sources/cardiogenic-shock-nejm-2026 (very high)
Post-cardiac arrest CS phenotype: cardiac stunning after ROSC; high lactate from no-flow does NOT correlate with cardiac index; 20–30% die from brain injury rather than circulatory failure sources/cardiogenic-shock-nejm-2026 (very high)
Ventricular involvement: RV present in 44% of AMI-CS; even more common in non-AMI-CS; biventricular profile carries adverse prognosis sources/cardiogenic-shock-nejm-2026 (very high)

SUSPECT CS — Early Diagnosis Mnemonic

Symptoms/Signs → altered mental status, cold/clammy extremities, low pulse pressure (<25% SBP), JVP elevation, crackles, orthopnea
Urine output → <30 mL/h (<0.5 mL/kg·h)
Sustained hypotension → SBP <90 mmHg, MAP <65 mmHg for >30 min (or >30 mmHg drop from baseline), or pharmacological/mechanical support to maintain SBP
Perfusion → lactate >2 mmol/L; ALT >200 U/L; creatinine ≥2× ULN; pH <7.2; metabolic acidosis
ECG/Echocardiogram → acute ischemia, STEMI, wall motion abnormalities; LV/RV dysfunction; valvular pathology
Congestion → physical/hemodynamic evidence; LV vs RV vs biventricular
Triage → shock team activation or transfer sources/cardiogenic-shock-acc-2025 (very high)

Initial diagnosis does NOT require invasive hemodynamics — clinical/laboratory/imaging data sufficient
Normotensive CS (end-organ hypoperfusion without hypotension) is associated with increased mortality and must not be missed

Severity Classification — SCAI Staging

See concepts/SCAI-Shock-Classification for full staging details.

SCAI Stage B patients are at highest risk of escalating shock severity within 24 hours
Most patients change SCAI stage within the first 24 hours — serial reassessment is critical

Systems of Care — Regionalized CS Centers

Level 1: full 24/7 expertise; full tMCS; durable LVAD + transplant capable
Level 2: intermediate capabilities; some tMCS
Level 3: community hospital; basic CV care only
AMI-CS refractory post-revascularization → almost always transfer to Level 1
≥1 vasoactive agent, tMCS consideration, or cardiac arrest → contact regional Level 1 center immediately
"It is never too early to contact the CS regional center" (writing committee) sources/cardiogenic-shock-acc-2025 (very high)
High-volume CS centers (≥107 CS cases/year) associated with improved outcomes in observational data — AHA 2017 hub-and-spoke threshold sources/cardiogenic-shock-aha-2017 (high)
Mobile ECMO teams as emerging strategy for high-acuity interhospital transfer sources/cardiogenic-shock-aha-2017 (high)

Shock Team Activation

Standardized interdisciplinary shock team associated with lower risk-adjusted CICU mortality
Core members: critical care cardiology, advanced HF/transplant, interventional cardiology, cardiac surgery ± ECMO/perfusion ± palliative care
Early contact with regional Level 1 center for Level 2/3 hospitals

Invasive Hemodynamic Monitoring

See concepts/Invasive-Hemodynamic-Monitoring-CS.

Cardiac power output/index is the single strongest hemodynamic predictor of mortality in CS (SHOCK trial registry) — superior to CI or MAP in isolation sources/mcs-ehj-2014 (medium)
CPO formula: CPO (watts) = (MAP × CO) / 451 sources/mcs-jic-2023 (high)
CPO/lactate stratification at 12–24h: CPO <0.6 W + lactate >4 mg/dL → device escalation; CPO >0.6 W + lactate <4 mg/dL → consider weaning catecholamines and tMCS sources/mcs-jic-2023 (high)
MODS severity (APACHE II / SAPS II) and SIRS biomarkers (IL-6, RAGE) predict mortality more accurately than hemodynamic indices after the first 24h; CI alone is unrelated to survival beyond 24h in AMI-CS sources/mcs-ehj-2014 (medium)
PAC use associated with improved outcomes (retrospective/registry data); no CS-specific RCT (PACCS trial ongoing)
Complete hemodynamic profiling (vs incomplete/none) → lower in-hospital mortality
Early hemodynamic assessment within 12 hours → improved clinical outcomes
Congestion profiles: LV dominant (PCWP >15 mmHg), RV dominant (CVP >15 mmHg + normal PCWP), biventricular (both elevated) — biventricular and RV profiles carry adverse outcomes

Pharmacological Management

Norepinephrine: reasonable first choice for most hypotensive CS patients
Pure vasopressors (phenylephrine alone) as first-line: strongly discouraged (reflex bradycardia reduces CO)
Inodilators/vasodilators: consider in normotensive CS with elevated SVR
Milrinone: caution with worsening renal function (renal clearance, long half-life)
DOREMI trial: dobutamine vs milrinone — no difference in primary composite endpoint sources/cardiogenic-shock-acc-2025 (very high)
No superior inotrope/vasodilator for mortality benefit established (Cochrane analysis)
Levosimendan: did NOT facilitate VA-ECMO weaning in a recent RCT; ongoing trials for other endpoints sources/cardiogenic-shock-nejm-2026 (very high)
Dopamine vs norepinephrine (n=1,679): dopamine → substantially more arrhythmic events; no mortality difference sources/cardiogenic-shock-nejm-2026 (very high)
Epinephrine vs norepinephrine: similar cardiac index but epinephrine → worse HR and lactic acidosis sources/cardiogenic-shock-nejm-2026 (very high)
Ongoing RCT: MAP 55 vs 65 mmHg target in AMI-CS sources/cardiogenic-shock-nejm-2026 (very high)
β-blockers and RAAS inhibitors: do NOT initiate or continue in active CS; resume only after hemodynamically stable ≥24 hours off vasopressors/inotropes sources/cardiogenic-shock-aha-2017 (high)
Use lowest possible dose for shortest possible duration
Address congestion: IV loop diuretics → thiazide augmentation → ultrafiltration/RRT
Fluids: only if hypovolemia without congestion AND leg-raise test positive; tailor strategy to LV-dominant vs RV-dominant failure

Temporary MCS

See concepts/Temporary-Mechanical-Circulatory-Support.

Routine tMCS in all CS patients is strongly discouraged
DanGer Shock: first positive tMCS RCT — microaxial flow pump in select STEMI-CS improved 180-day survival (HR 0.74; 12.7% absolute mortality reduction); benefit sustained up to 10 years sources/cardiogenic-shock-acc-2025 (very high) sources/cardiogenic-shock-nejm-2026 (very high)
Only 5% of all CS patients and 32% of STEMI-CS patients meet DanGer Shock eligibility criteria sources/cardiogenic-shock-nejm-2026 (very high)
IABP-SHOCK II and ECLS-SHOCK: negative (no mortality benefit); Altshock-2 (HF-CS; n=101): IABP also negative in HF-CS
4-trial VA-ECMO IPD meta-analysis: no mortality benefit + consistently higher complication rates across all devices sources/cardiogenic-shock-nejm-2026 (very high)
IPD meta-analysis (9 tMCS trials; n=1,059; 6-month follow-up): no overall mortality benefit; benefit only in LV-dominant, low hypoxic brain injury risk subgroup (HR 0.77; P=0.024)
VA-ECMO potential harm: retrograde aortic flow increases LV afterload; LV venting strategies (including transseptal cannula) showed no mortality benefit in RCT
Goal: ventricular unloading + restore perfusion; bridge to recovery, advanced therapies, or palliation
HF-CS: MCS only if chance of myocardial recovery OR eligible for durable LVAD/transplant
Early palliative care consultation if not candidate for durable LVAD/transplant/recovery

Revascularization Strategy in AMI-CS

Early revascularization: no 30-day benefit in SHOCK trial but reduced mortality up to 6 years → highly recommended sources/cardiogenic-shock-nejm-2026 (very high)
70–80% of AMI-CS have multivessel CAD
CULPRIT-SHOCK: culprit-only PCI (45.9%) vs immediate multivessel PCI (55.4%) composite of death+RRT (RR 0.83; P=0.01) — driven by mortality; culprit-only PCI is the standard; staged revascularization after stabilization in most survivors sources/cardiogenic-shock-nejm-2026 (very high)
Pharmacoinvasive approach (fibrinolysis + subsequent PCI): may benefit STEMI-CS with prolonged interhospital transport (observational)
If not amenable to PCI: CABG may be considered

Critical Care — Recognize/Rescue → Optimize → Stabilize → De-Escalate/Exit

Recognize/Rescue: Identify CS, restore tissue perfusion (first 24 hours; "golden hour")
Optimize: Pharmacological support; target MAP >60–65 mmHg
Stabilize: End-organ function recovery; mitigate extra-cardiac derangements
De-Escalate/Exit: Assess myocardial recovery → durable LVAD / heart transplant / palliative care sources/cardiogenic-shock-acc-2025 (very high)

Renal Replacement Therapy

AKI prevalence in CS: 13–28%; ~20% require RRT during hospitalization sources/cardiogenic-shock-aha-2017 (high)
CRRT preferred over intermittent hemodialysis in hemodynamically unstable CS (better tolerance; avoids fluid shifts) sources/cardiogenic-shock-aha-2017 (high)
KDIGO Stage 2 AKI threshold for CRRT initiation; early initiation (before conventional indications) has no outcome benefit sources/cardiogenic-shock-aha-2017 (high)

Complications

Bleeding: up to 60% in AMI-CS; 4× higher limb ischemia with tMCS (large-bore arterial access)
Limb ischemia: 2× higher risk of in-hospital death
Mechanical ventilation: PPV reduces LV afterload and augments stroke volume in LV failure; PEEP effects vary with preload dependence, LV contractility, and RV failure status

tMCS Weaning

Daily readiness assessment: hemodynamic stability, vasoactive drug burden, volume status, cause correction
Stepwise flow reduction: 0.5–1 L/min decrease every 2–4 hours
Advance HF/transplant consult before weaning to determine recovery vs durable LVAD vs transplant eligibility
Acute-on-chronic HF-CS may require prolonged inotrope wean after tMCS removal

Contradictions / Open Questions

tMCS in AMI-CS: DanGer Shock positive (STEMI-CS, HR 0.74) but only 5% of all CS and 32% of STEMI-CS meet eligibility; ECLS-SHOCK and IABP-SHOCK II negative; 4-trial VA-ECMO IPD meta-analysis negative — patient selection is decisive, not device class
VA-ECMO retrograde afterload: VA-ECMO may harm the LV; LV venting strategies proposed but transseptal cannula RCT showed no mortality benefit — optimal unloading strategy unresolved
PAC guidance: no RCT evidence in CS; observational/registry data suggest benefit; ESCAPE trial inapplicable; PACCS trial ongoing — practice currently based on observational data only
Optimal MAP target: >65 mmHg is standard; ongoing RCT testing 55 vs 65 mmHg — lower target may reduce afterload and benefit LV but risks organ hypoperfusion
HF-CS evidence void: all positive RCT data is from STEMI-CS; HF-CS management is expert consensus; Altshock-2 (IABP, n=101) negative; no positive tMCS RCT in HF-CS
Levosimendan: did not facilitate VA-ECMO weaning (RCT); other endpoints in CS unclear pending further trials
Inotrope choice: no mortality-reducing inotrope established; dobutamine ≈ milrinone (DOREMI); epinephrine inferior metabolic profile vs norepinephrine; practice varies widely
Frailty and MCS: 71% of AMI-CS patients are frail — for these patients, device-related complications (bleeding, limb ischemia) may outweigh MCS benefit
Normotensive CS: associated with increased mortality but less studied than hypotensive CS

Connections

Related to concepts/SCAI-Shock-Classification
Related to concepts/Temporary-Mechanical-Circulatory-Support
Related to concepts/IABP
Related to concepts/ECPELLA
Related to concepts/Invasive-Hemodynamic-Monitoring-CS
Related to concepts/Vasoactive-Agents-in-CS
Related to concepts/Pulmonary-Artery-Pulsatility-Index