Cardiogenic shock
SCAI stages A (at risk) → B (beginning, no hypoperfusion) → C (classic hypoperfusion) → D (deteriorating) → E (extremis).
The vicious cycle
Low cardiac output raises preload (wet) and drops MAP; the body answers with high SVR (cold); stroke volume falls further. The way out is to restore MAP, then CO, then get a reversible lesion to the lab — not to stack inotropes while you wait for “one more lactate.”
A
At risk
Ischemia, cardiomyopathy, or valve disease without hypoperfusion yet. Watch and prevent.
B
Beginning
Hemodynamically unstable (hypotension, tachycardia) without hypoperfusion. This is the last easy save.
C
Classic
Hypoperfusion: oliguria, ↑ lactate, ↑ creatinine. May still answer to the first pressor / inotrope / revascularization.
D
Deteriorating
No improvement on the first round. Escalate — second agent, MCS, team — do not linger.
E
Extremis
Refractory to escalated therapy: arrest, collapsing MAP, crashing gas exchange. Crash MCS or it is over.
JSCAI 2021;1:1. Stage, not just “on levo,” is what you sign out.
Warm · dry
Compensated
Not . Do not start inotropes for a number on the echo.
Warm · wet
Congested, perfused
Diurese; vasodilate if SVR is high. Nitroprusside is superb afterload reduction and dangerous in unrevascularized CAD.
Cold · dry
Empty and hypoperfused
Fill if CVP is low; then inotrope. Phenylephrine if the lesion is HOCM or critical AS.
Cold · wet
The death spiral
Norepinephrine for MAP, inodilator for CO, diuresis once MAP is safe, early MCS if they are not turning.
Immediate moves
- ECG + troponin for ischemia. TTE to exclude tamponade, mechanical complications, and MCS contraindications.
- AMI, tamponade, or a mechanical lesion → cath lab and/or surgery now ( trial, ). Emergency revascularization improved 6- and 12-month survival.
- Call the team early. Escalating inotropes without a plan tracks with worse outcomes. There is positive evidence for early MCS (DanGer ).
- Stabilize MAP with norepinephrine before you chase fancy numbers.
Central line
- CVP
- ScvO2 — a rough Fick estimate of CO / CI; not as good as mixed venous
PA catheter
- CVP, PAS, PAD, PCWP, MvO2
- CO / CI by Fick (VO2 / [CaO2 − CvO2]) and by thermodilution
Tailored therapy
Trend lactate, LFTs, and creatinine every 4 hours so you know whether the last move worked. The job is perfusion: raise CO by fixing preload, afterload, and contractility.
| Lever | Goal | How |
|---|---|---|
| Preload | PCWP 14–18, PAD 16–20, CVP 8–12 | LVEDV ∝ LVEDP ≈ PCWP; PAD moves with PCWP. Diurese or RRT to come down. Right-heart numbers are the honest volume exam. |
| Afterload | SVR 800–1200, MAP 65–75 | SVR = (MAP − CVP) / CO. For a given MAP, ↓ SVR ↑ CO. Vasodilators down, vasopressors up. |
| Contractility | CI >2.0–2.2, CO >4, MvO2 >60 (or ScvO2 >70) | Inotropes after preload and afterload are no longer the whole problem. |
Vasodilators and vasopressors
- Vasodilators: captopril, hydralazine, isosorbide dinitrate, nitroprusside infusion (avoid unrevascularized CAD), nitroglycerin infusion.
- Once stable, cross-titrate short-acting afterload reducers onto GDMT — the long-acting agents are the ones that remodel the ventricle.
- Vasopressors (norepinephrine, epinephrine, phenylephrine, vasopressin) raise afterload. You still need them to hold MAP in mixed and to offset inodilator vasodilation.
Inotropes
| Drug | Start | Watch |
|---|---|---|
| Dobutamine (inodilator) | 2 mcg/kg/min. β1 > β2, ↑ cAMP | Tachycardia, faster ventricular response to AF, VT, ischemia, hypotension. Tachyphylaxis after 24–48 h. |
| Milrinone (inodilator) | 0.125 mcg/kg/min. PDE-3, ↓ cAMP breakdown | Longer half-life than dobutamine, more pulmonary vasodilation, slightly less chronotropy. Preferred in RV failure. Renally cleared. Common home inotrope. Hypotension, VT, ischemia. |
| Epinephrine (inopressor) | Add when hypotension is severe, often on top of an inodilator | Arrhythmias, digital ischemia. |
- Look for RV failure with PAPi or the CVP / PCWP ratio, and for RV afterload with PVR = (mPAP − PCWP) / CO. See Right ventricular failure.
- If medicines are failing: MCS and transplant evaluation. Call advanced HF. DanGer : early microaxial flow pump (Impella CP) in STEMI cut 180-day mortality, with more bleeding, hemolysis, and limb ischemia.