Cardiogenic Shock

Definition

A cardiac disorder that produces both clinical and biochemical evidence of sustained tissue hypoperfusion, irrespective of blood pressure. There is no specific blood-pressure threshold; lactate >2 mmol/L supplies the biochemical evidence of hypoperfusion. Cardiogenic shock is one of the most common causes of admission to contemporary cardiac intensive care units, carrying 30%–40% short-term mortality and approximately 50% at one year. (sources/cardiogenic-shock-acc-2025, rating: very high)

This page covers the condition and its management. Decompensated heart failure without shock — decompensated left- and right-sided failure and acute pulmonary oedema — is on concepts/Decompensated-HF-Management; device mechanics are on concepts/IABP, concepts/ECPELLA and concepts/Pulmonary-Artery-Pulsatility-Index; individual trials have their own entity pages.

Key Concepts

Epidemiology

Phenotypes and Aetiology — the SARC Classification

The Shock Academic Research Consortium divides shock by cause rather than by device, because cause predicts outcome more strongly than haemodynamics:

Early Recognition — SUSPECT CS

Diagnosis does not require invasive haemodynamics; clinical, laboratory and imaging data suffice.

Letter Domain Threshold
S Symptoms and signs Altered mental status, cold/clammy extremities, pulse pressure <25% of systolic, raised JVP, crackles, orthopnoea
U Urine output <30 mL/h (<0.5 mL/kg·h)
S Sustained hypotension SBP <90 or MAP <65 mmHg for >30 min, a fall of >30 mmHg from baseline, or support needed to maintain pressure
P Perfusion Lactate >2 mmol/L; ALT >200 U/L; creatinine ≥2× ULN; pH <7.2
E ECG and echocardiogram Acute ischaemia, STEMI, wall-motion abnormality, LV/RV dysfunction, valvular pathology
C Congestion Physical or haemodynamic evidence; LV versus RV versus biventricular
T Triage Shock-team activation or transfer

(sources/cardiogenic-shock-acc-2025, rating: very high)

Normotensive shock — end-organ hypoperfusion without hypotension — carries increased mortality and is the presentation most easily missed.

Severity — The SCAI Stages

The Society for Cardiovascular Angiography and Interventions system classifies severity from "at risk" to "extremis" on clinical, haemodynamic and biochemical grounds. The ACC 2025 guidance endorses it as the standard severity tool. (sources/cardiogenic-shock-acc-2025, rating: very high; sources/cardiogenic-shock-nejm-2026)

Stage Features
A — At risk No signs of shock, but at risk (large MI, HF exacerbation); normal haemodynamics; lactate ≤2 mmol/L
B — Beginning Relative hypotension or tachycardia without hypoperfusion; filling pressures may be elevated; lactate ≤2 mmol/L
C — Classic Hypoperfusion requiring intervention; lactate >2 mmol/L; CI <2.2 L/min/m²; PCWP >15 mmHg
D — Deteriorating Rising or persistently elevated lactate; escalating pressors or addition of MCS; deterioration despite support
E — Extremis Lactate >8 mmol/L; profound hypotension despite maximal support; often cardiac arrest or CPR

Right heart catheterisation values map onto the stages:

Phenotype RAP PAWP CI (L/min/m²) MAP SVRi Profile Lactate
A — At risk ≤10 mmHg ≤15 mmHg ≥2.5 ≥60 mmHg normal warm and dry normal
B — Beginning >10 mmHg >15 mmHg ≥2.5 ≥60 mmHg normal warm and wet normal
C — Classic >10 mmHg >15 mmHg <2.5 <60 mmHg increased cold and wet ≥2 mmol/L
D — Deteriorating >10 mmHg >15 mmHg <2.2 <60 mmHg decreased cold and wet ≥2 mmol/L
E — Extremis >10 mmHg >20 mmHg <1.8 <60 mmHg decreased cold and wet ≥8 mmol/L

(sources/rhc-hf-ehj-2025, rating: high)

The framework also discriminates the two important mimics, which SCAI staging alone does not: (sources/rhc-hf-ehj-2025)

Phenotype PAWP CI (L/min/m²) SVRi Profile
Vasodilatory (septic, allergic) ≤15 mmHg ≥2.5 decreased warm and dry
Mixed shock >15 mmHg <2.2 or ≥2.2 decreased or normal warm or cold and wet
Isolated right ventricular <18 mmHg (RAP:PAWP ≥0.8) <2.2 increased RAP >14 mmHg; RVSWI low

Prognosis is stepwise and trajectory-dependent:

Systems of Care and the Shock Team

Invasive Haemodynamic Monitoring

Vasopressors and Inotropes

No vasoactive agent has demonstrated a mortality benefit in shock. Use the lowest dose for the shortest duration, and address congestion in parallel: IV loop diuretics → thiazide augmentation → ultrafiltration or renal replacement. (sources/cardiogenic-shock-acc-2025, rating: very high)

Agent Class Key data Caution
Norepinephrine Vasopressor First-line; balanced alpha/beta activity —
Dopamine Vasopressor/inotrope More arrhythmic events vs norepinephrine (n=1,679); no mortality difference Avoid as first-line
Epinephrine Vasopressor/inotrope Similar cardiac index to norepinephrine but worse heart rate and lactic acidosis Metabolic confound
Phenylephrine Pure vasopressor Reflex bradycardia reduces cardiac output Strongly discouraged as first-line
Dobutamine Inotrope Equivalent to milrinone (DOREMI) Tachyarrhythmia
Milrinone Inodilator Equivalent to dobutamine (DOREMI) Renally cleared, long half-life — caution with worsening renal function
Levosimendan Calcium sensitiser / inodilator Failed a dedicated VA-ECMO weaning RCT; the only inotrope with zero myocardial oxygen cost Monotherapy only if SBP >90 mmHg

Revascularisation in AMI-CS

Temporary Mechanical Circulatory Support

Temporary MCS augments cardiac output, unloads the ventricle and restores perfusion as a bridge to recovery, durable LVAD, transplantation or palliation. Common devices are the intra-aortic balloon pump, the microaxial flow pump and VA-ECMO. (sources/cardiogenic-shock-acc-2025, rating: very high)

Why haemodynamics alone are insufficient. Once multiorgan dysfunction is established, raising cardiac output may not reverse end-organ failure. Three prerequisites must hold for MCS to translate into survival: early timing before MODS is established; adequate restoration of cardiac index; and prevention of device-related complications. MCS should therefore not be last-resort therapy — early initiation limits high-dose catecholamine microvascular toxicity. (sources/mcs-ehj-2014, rating: medium)

Device haemodynamics on the pressure-volume loop. Pressure-volume area is linearly related to myocardial oxygen consumption: (sources/mcs-jic-2023, rating: high)

Four mechanistic categories organise the percutaneous devices: LV pressure unloading (IABP), LV volume unloading (TandemHeart, Impella), biventricular support without oxygenation, and biventricular support with oxygenation (VA-ECMO). (sources/mcs-ehj-2014)

What the trial evidence shows:

Trial or analysis Population Result
DanGer Shock (n=360) STEMI-related shock, selected Positive — 180-day HR 0.74 (95% CI 0.55–0.99); 12.7% absolute mortality reduction; benefit sustained to 10 years; more bleeding, limb ischaemia and RRT
IABP-SHOCK II (n=600) AMI-related shock Negative at 30 days and at 6 years
ECLS-SHOCK (n=420) AMI-related shock Negative — routine early VA-ECMO does not improve outcomes
Altshock-2 (n=101) HF-related shock Negative — IABP did not improve survival or bridge to replacement at 60 days
VA-ECMO 4-trial IPD meta-analysis AMI-related shock No mortality benefit; consistently more complications
9-trial IPD meta-analysis (n=1,059) Mixed No overall benefit; HR 0.77 (0.61–0.97) only in LV-dominant, low anoxic-brain-injury-risk patients

(sources/cardiogenic-shock-acc-2025, rating: very high; sources/cardiogenic-shock-nejm-2026)

Device classes in brief. The IABP provides counterpulsation at the lowest support level (~1 L/min increase) with no mortality benefit in either AMI- or HF-related shock and is recommended for mechanical complications in European but not US guidelines; full detail on concepts/IABP. The microaxial flow pump gives continuous LV unloading (CP 4.3 L/min, 5.5 up to 5.5 L/min) and is the only device with a positive RCT, though large propensity-matched series consistently show no benefit with more complications. VA-ECMO gives full cardiopulmonary support up to 6 L/min without unloading the LV. TandemHeart is rarely used. (sources/cardiogenic-shock-nejm-2026)

Routine versus selective use. Routine temporary MCS in all shock patients is strongly discouraged. Selection rests on the cardiac index required, the device's capacity and complication risk, and the haemodynamic profile; a microaxial flow pump may be considered in LV-dominant STEMI-related shock with clinical hypoperfusion. (sources/cardiogenic-shock-acc-2025)

Complication burden scales with device size:

Device Bleeding Limb ischaemia Stroke
IABP 12.9% 1.5% 3.1%
Impella 27.7% 4.2% 4.9%
VA-ECMO 28.2% 14.3% 8.2%

(sources/mcs-jic-2023, rating: high)

Escalation. If support is inadequate for the cardiac index, escalate the device; if unloading is inadequate, increase flow, move to a larger device (CP to 5.5), address afterload by venting the LV on VA-ECMO, or relieve congestion. Delay worsens end-organ perfusion and is lethal.

Right ventricular support and the durable bridge. Impella RP is a percutaneous intracardiac pump from IVC to pulmonary artery, approved under humanitarian device exemption on RECOVER RIGHT; TandemHeart in an RV configuration has case-series data only; CentriMag provides surgical biventricular support up to 10 L/min without RCT evidence. INTERMACS profile 1–2 patients carry 38% 30-day mortality after durable implant, and implants in active shock fell from 40% to 12% between 2006 and 2010 — reflecting recognition that implanting during active shock is prohibitive. A bridge-to-bridge strategy, stabilising on temporary support before durable LVAD, is preferred; 44% of INTERMACS 1–2 durable implants were bridge-to-transplant, and transplant evaluation should run concurrently. (sources/cardiogenic-shock-aha-2017)

Weaning and De-escalation

Assess readiness daily on four axes: haemodynamic stability, total vasoactive drug burden, volume status, and correction of the underlying cause. (sources/cardiogenic-shock-acc-2025, rating: very high)

Organ Support and the Critical Care Sequence

The care pathway runs Recognise/Rescue → Optimise → Stabilise → De-escalate: identify shock and restore perfusion in the first 24 hours; titrate pharmacological support toward MAP >60–65 mmHg; recover end-organ function and mitigate extracardiac derangement; then assess recovery against durable LVAD, transplant or palliation. (sources/cardiogenic-shock-acc-2025, rating: very high)

Contradictions / Open Questions

Connections

Sources