Cardiogenic shock resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ahmed Zaghw, M.D. [2]

Definition

It is a state of end-organ hypoperfusion due to myocardial dysfunction, associated with hemodynamic changes for 30 mins or more which is not due to hypovolemia and not responsive to fluids alone:

• SBP < 80 mmHg or MAP < 30 mmHg than baseline
• Cardiac index ( CI ) < 1.8 L.Min^-1·M^-2 without vasopressors support or CI 2.0 to 2.2 L.Min^-1·M^-2 with vasopressors support.
• Elevated filling pressures LVEDP > 18 mmHg, RVEDP > 10 mmHg

Causes of Cardiogenic Shock (CS)

• Pump problems: LV failure mainly in anterior wall MI still is the most common cause for CS and cardiomyopathy post-MI is the second most common.
• Mechanical problems: Ventricular septal rupture, contained free wall rupture, and papillary muscle rupture. Mechanical problems are strongly suspected in non anterior MI. However cardiac tamponade, tension pneumothorax) and aortic stenosis are recently considered as obstructive shock.
• Electrical problems: is the least commonly cause for CS and most commonly occurs due toVF or VT and AF.

Prognosis

• CS occurs in 8% of hospitalized STEMI patient with a mortality rate of 50-60% within 30 days.
• CS is associated with more severe lesions in coronary territories with 53% with three vessel diseases and 16 with only left main disease.
• The mortality rate is significantly higher when the culprit lesion is in a left main or saphenous vein graft than in those with circumflex, left anterior descending, or right coronary artery lesions.
• There is no difference in CS mortality rate between STEMI and NSTEMI.
• The left ventricular ejection fraction (LVEF) and severity of mitral regurgitation (MR) are echocardiographic predictors for mortality in the outcomes of CS.

• The only way to prevent CS is an early reperfusion therapy for MI.

Management

Shock

ABCD Airway / O2 / 2 wide bore IV access / 12-lead ECG / focused H&P / CXR PA / Arterial line monitoring

Hemodynamic optimization *Fluid therapy *Vasopressors

Do Not give β Blockers Ca Channel antagonist

ECG evidence of STEMI †

ECG inconclusive

ECG: -ve Clinical history of HF

STEMI

Echocardiography rule out Acute valvular lesions

Heart failure

Echocardiography to associated valvular causes ††

Surgical correction

Treatment of heart failure

PCI capable center

PCI Non-capable center

Urgent PCI

Transfer to PCI center < 120 min

Transfer to PCI center > 120 min

Urgent Transfer to PCI

Thrombolytics

Get stable

Still Non stable * Hypotension * ECG evidence

Transfer to PCI center within 3-24 hrs after Thrombolytics

Urgent Transfer to PCI center

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† New ST elevation at the J point in at least 2 contiguous leads of 2 mm in men or 1.5 mm in women in leads V2-V3 and/or of 1 mm in other contiguous chest leads or the limb leads.

†† Early echocardiography should be done before PCI as long as the patient is not crashing, as it may change the treatment course.

Do's

• Cardiogenic shock occurs in 5-8% of hospitalized STEMI patient.
• Cardiac Echocardiography (Transthoracic) is helpful to rule out mechanical problems when the initial ECG findings are not conclusive or when the cardiogenic shock occurs with the first non anterior MI.
• Echocardiography should be performed early before PCI unless the diagnosis is extensive anterior MI and the patient is undergoing prompt percutaneous coronary intervention (PCI).
• Transfer the STEMI patients with cardiogenic shock to PCI irrespective to time delay from time of presentation.

Don'ts

• Do not routinely use an intraaortic balloon pump (IABP)in all MI patients complicated by cardiogenic shock (CS) whom are planned to have primary percutaneous coronary intervention (PCI) is attempted or performed or in whom fibrinolytic therapy is administered.