CARDIOGENIC SHOCK

Question 1

Define cardiogenic shock.

Answer 1

Cardiogenic shock is a state of end-organ hypoperfusion due to cardiac failure and the inability of the cardiovascular system to provide adequate blood flow to the extremities and vital organs.

Patients manifest persistent hypotension with severe reduction in cardiac index in the presence of adequate or elevated filling pressure.

Question 2

What are the various types of shock?

Answer 2

The three main types of shock are:
* Hypovolemic
* Vasogenic (or distributive)
* Cardiogenic

Examples include gastrointestinal bleeding for hypovolemic shock and septic shock for vasogenic shock.

Question 3

What is the most common cause of cardiogenic shock?

Answer 3

Acute myocardial infarction (AMI) is the most common cause of cardiogenic shock.

It occurs in 5% to 8% of hospitalized patients with ST-segment elevation MI (STEMI).

Question 4

What are the clinical signs observed in cardiogenic shock?

Answer 4

Clinical signs include:
* Hypotension
* Oliguria
* Clouded sensorium
* Cool and mottled extremities

Distended jugular veins and rales may also suggest cardiogenic shock.

Question 5

Do all patients with cardiogenic shock have an increased heart rate?

Answer 5

No, some patients can present with bradycardia, especially those related to third-degree heart block or drug overdose.

Temporary transvenous pacemaker implantation may be required.

Question 6

What is the normal range for central venous pressure (CVP)?

Answer 6

The normal central venous pressure (CVP) is 5 to 12 cm H2O.

Intravascular volume, intrathoracic pressure, RV function, and venous tone all affect CVP.

Question 7

How can one differentiate cardiogenic from septic shock?

Answer 7

In septic shock, systemic vascular resistance (SVR) and pulmonary capillary wedge pressure (PCWP) are reduced, and cardiac output is increased, opposite to cardiogenic shock findings.

Significant decreases in cardiac output may occur in advanced sepsis stages.

Question 8

What is the role of neurohormonal activation in cardiogenic shock?

Answer 8

Neurohormonal activation promotes salt and water retention, which may improve perfusion but exacerbate pulmonary edema.

It can also lead to increased afterload.

Question 9

List major cardiovascular causes of cardiogenic shock.

Answer 9

Major causes include:
* Acute myocardial infarction with severe left ventricular dysfunction
* Aortic dissection
* Endocarditis
* Cardiac tamponade
* Massive pulmonary embolism
* Chronic congestive cardiomyopathy
* Takotsubo cardiomyopathy
* Brady- or tachyarrhythmias
* Critical mitral or aortic stenosis
* Toxins or drugs
* Traumatic cardiogenic shock
* Left atrial myxoma

Mechanical complications after myocardial infarction should also be considered.

Question 10

What is the significance of a loud holosystolic murmur in a patient with shock after acute myocardial infarction?

Answer 10

It may indicate either acute mitral regurgitation or an acute ventricular septal defect (VSD).

These conditions can cause shock due to reduced forward blood flow.

Question 11

What is the mortality rate of cardiogenic shock?

Answer 11

The mortality rate ranges between 30% and 50%, with severe refractory cardiogenic shock exceeding 50%.

The SHOCK trial showed long-term survival benefits from early revascularization.

Question 12

What is the mainstay therapy for cardiogenic shock complicating myocardial infarction?

Answer 12

Acute reperfusion and prompt revascularization improve survival substantially.

The SHOCK study demonstrated lower mortality in the early revascularization group.

Question 13

Which is the best revascularization strategy in patients with cardiogenic shock complicating myocardial infarction?

Answer 13

Among patients assigned to revascularization, PCI accounted for 64% and CABG for 36% of initial revascularization attempts.

Survival rates were similar with both strategies.

Question 14

Fill in the blank: Cardiogenic shock is characterized by _______.

Answer 14

[end-organ hypoperfusion due to cardiac failure]

Question 15

True or False: All patients with cardiogenic shock will show warm skin.

Answer 15

False

Question 16

What are the determinants of central venous pressure?

Answer 16

Determinants include:
* Intravascular volume
* Intrathoracic pressure
* RV function
* Venous tone

CVP should be measured at the end of expiration to reduce variability.

Question 17

Describe the pathophysiology of cardiogenic shock in acute myocardial infarction.

Answer 17

LV pump failure causes decreased cardiac output, leading to hypoperfusion, catecholamine release, increased myocardial oxygen demand, and neurohormonal activation.

This can create a downward spiral worsening myocardial ischemia.

Question 18

What percentage relative improvement in 6-year survival was associated with early revascularization?

Answer 18

67%

This improvement is compared with initial medical stabilization.

Question 19

What were the initial revascularization attempts in the SHOCK trial for patients with cardiogenic shock?

Answer 19

• PCI: 64%
• CABG: 36%

PCI stands for percutaneous coronary intervention, and CABG stands for coronary artery bypass grafting.

Question 20

Which revascularization strategy is recommended by the ACC/AHA guidelines for patients with cardiogenic shock and multivessel coronary artery disease?

Answer 20

Coronary artery bypass grafting (CABG)

Staged multivessel PCI may be performed if surgery is not an option.

Question 21

What is established as a superior strategy in patients with AMI-complicated cardiogenic shock according to the CULPRIT-SHOCK trial?

Answer 21

Culprit-lesion-only PCI

This contrasts with STEMI patients without cardiogenic shock, where complete revascularization is safe and effective.

Question 22

What is the desired time from first medical contact to device activation in STEMI patients with cardiogenic shock?

Answer 22

Less than 90 minutes

Timely PCI is crucial for effective treatment.

Question 23

What should be avoided in the medical therapy for patients with cardiogenic shock?

Answer 23

• Beta-blockers
• Calcium-channel inhibitors
• Vasodilators

These can precipitate cardiogenic shock in patients with low cardiac output.

Question 24

What are the common antiplatelet and antithrombotic therapies administered to patients with myocardial infarction?

Answer 24

• Aspirin
• Heparin

These therapies are critical for all patients with MI.

Question 25

What is the role of inotropic agents in the treatment of cardiogenic shock?

Answer 25

Short-term hemodynamic improvement

They increase myocardial ATP consumption, leading to increased oxygen demand.

Question 26

Which vasopressor is recommended for severe hypotension in cardiogenic shock?

Answer 26

Norepinephrine

It is preferred over dopamine due to lower mortality rates.

Question 27

What are percutaneous circulatory assist devices (PCADs) used for?

Answer 27

Support patients with cardiogenic shock before, during, and after revascularization

They help interrupt cycles of ischemia, hypotension, and myocardial dysfunction.

Question 28

What are the advantages of the intra-aortic balloon pump?

Answer 28

• Ubiquitous availability
• Ease of percutaneous implantation
• Minimizes vascular complications
• Fiber-optic technology
• Range of balloon sizes

It can enhance diastolic augmentation and systolic unloading.

Question 29

What are the potential disadvantages of the intra-aortic balloon pump?

Answer 29

• Limited cardiac output support
• Synchronization reliance with cardiac cycle
• Risk of displacement, rupture, or leak
• Infection
• Aortic dissection

These risks can complicate its use in patients.

Question 30

What is the maximum cardiac output augmentation provided by the Impella device?

Answer 30

Up to 4 L/min

This device can support circulation for up to 7 days.

Question 31

What is a significant disadvantage of the TandemHeart device?

Answer 31

Requires specific expertise for implantation

It involves transseptal punctures and has a relatively long implantation time.

Question 32

True or False: The intra-aortic balloon pump device has shown a survival benefit in patients with AMI complicated by cardiogenic shock.

Answer 32

False

The IABP-SHOCK II trial indicated no survival benefit.

Question 33

What is the function of the Impella device in patients with cardiogenic shock?

Answer 33

Unloads the left ventricle and provides short-term mechanical support

It reduces end-diastolic wall stress and improves coronary flow.