Acute Coronary Syndromes Flashcards

1
Q

Acute Coronary Syndromes (ACS) in the US

How many Americans a year have an MI? How many will die from a MI?

A
  • 750,000 americans
  • 116,000 will die (about 15%)
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2
Q

Acute Coronary Syndromes (ACS) in the US

Heart disease accounts for 1 in ?? deaths in U.S., killing over 370,000 per year.

A

7 deaths

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3
Q

ACS

Describe the continuum of ACS.

A
  1. unstable angina
  2. Non-ST-elevation MI (NSTEMI)
  3. ST-elevation MI (STEMI)
  • 1 and 2 and due to partially occlusive intracoronary thrombus.
  • 3 is due to totally occlusive intracoronary thrombus
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4
Q

ACS

What are both Unstable Angina (UA) and Non-ST elevation myocardial infarction (NSTEMI) caused by?

A

partially occlusive intracoronary thrombus from plaque rupture

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5
Q

ACS

What is it called when a partially occluded intracoronary thrombus causes some necrosis?

A

NSTEMI

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6
Q

ACS

What is it called when a partially occluded intracoronary thrombus causes no necrosis?

A

UA

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7
Q

Acute Myocardial Infarction: STEMI

Coronary thrombosis results from plaque rupture with superimposed:

A
  1. rapid platelet aggregation (clumping at site of rupture)
  2. vasoconstriction: stimulated by the release of thromboxane A2 from platelets
  3. formation of intracoronary fibrin clot
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8
Q

Acute Myocardial Infarction: STEMI

What percentage of acute STEMI are due to acute vasospasm?

A

10%

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9
Q

Normal Hemostasis

What are the 3 primary steps in normal hemostasis?

A
  1. vasoconstriction of the blood vessel
  2. platelet plug
  3. blood coagulation
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10
Q

Normal Hemostasis

What is the purpose of vasoconstriction?

A

to reduce blood flow and prevent blood loss

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11
Q

Normal Hemostasis

What are the main secreting cells that stimulate vasoconstriction?

A

endothelial cells and platelets

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12
Q

Normal Hemostasis

What triggers the vasoconstriction in blood vessels?

A

reduced nitric oxide bioavailability

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13
Q

Normal Hemostasis

What is a platelet plug?

A

temporary blockage of bleeding

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14
Q

Normal Hemostasis

What portion of hemostasis is the platelet plug considered?

A

primary hemostasis

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15
Q

Normal Hemostasis

What is blood coagulation?

A

formation of a clot that seals the hole until tissues are repaired

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16
Q

Normal Hemostasis

What portion of hemostasis is blood coagulation considered?

A

secondary hemostasis

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17
Q

Normal Hemostasis: Primary

Define Primary hemostasis.

A

1st line of defense against bleeding which occurs within seconds

18
Q

Normal Hemostasis: Primary

Describe the general first 4 steps of primary hemostasis.

A

a. endothelial surface of blood vessel damaged
b. platelets become activated
c. formation of platelet plug
d. Thromboxane (TXA2) causes vasoconstriction

19
Q

Normal Hemostasis: Primary

What does the exposure of the subendothelium collagen attract? Why?

A
  • platelet attraction and adhesion
  • collagen is very thrombogenic
20
Q

Normal Hemostasis: Primary

After adhesion to subendothelium collagen, what do platelets begin to release? What does this cause?

A
  • release ADP and fibrinogen
  • causes aggregation of platelets
21
Q

Normal Hemostasis: Primary

What do the aggregated platelets become at the site of the vessel injury?

A

the platelet plug

22
Q

Normal Hemostasis: Primary

How does thromboxane (TXA2) prevent blood loss?

A

inducing vasoconstriction

23
Q

Normal Hemostasis: Secondary

How long does it take for secondary hemostasis to occur?

A

within hours

24
Q

Normal Hemostasis: Secondary

What are the 3 general steps of secondary hemostasis?

A

a. subendothelial tissue factor
b. formation of a fibrin clot
c. tissue plasminogen activator (tPA)

25
Q

Normal Hemostasis: Secondary

What activates plasma coagulation pathways when exposed?

A

subendothelial tissue factor

26
Q

Normal Hemostasis: Secondary

What is the purpose of a fibrin clot formation?

A

stabilization and strengthening of platelet plug

27
Q

Normal Hemostasis: Secondary

What cell type produces tPA?

A

endothelium

28
Q

Normal Hemostasis: Secondary

What is the purpose of tPA?

A

dissolving the fibrin clot via the enzyme plasmin after injury becomes healed

29
Q

Tissue Factor (Extrinsic) pathway

Step 1: Trauma (plaque rupture) causes ?? to become exposed.

A

tissue factor

30
Q

Tissue Factor (Extrinsic) pathway

Step 2: Tissue factor converts ?? into ??.

A
  • factor X
  • factor Xa
31
Q

Tissue Factor (Extrinsic) pathway

Step 3: Factor Xa activates enzyme ?? to form ??.

A
  • prothrombin
  • thrombin
32
Q

Tissue Factor (Extrinsic) pathway

Step 4: Thrombin converts ?? to ??.

A
  • fibrinogen
  • fibrin
33
Q

Tissue Factor (Extrinsic) pathway

Step 5: Fibrin is crucial for the formation of ??.

A

cross-linked clot

34
Q

Tissue Factor (Extrinsic) pathway

During normal hemostasis, the process concludes with lyses by which enzyme? What activates this enzyme?

A
  • plasmin
  • tissue plasminogen activator (tPA)
35
Q

Tissue Factor (Extrinsic) pathway

Why is normal lyses ineffective during a plaque rupture?

A

tPA is overwhelmed and cannot keep up with the clot formation

36
Q

Possible Symptoms of Acute MI

List any symptoms that can be solo or in combination with any other:

A
  • angina
  • dyspnea
  • diaphoresis
  • pallr
  • hypotension
  • syncope or pre-syncope
37
Q

Two important points of acute MI

Up to 25% of patients have ?? during MI.

A

no symptoms

38
Q

Two important points of acute MI

?? are more common to have atypical symptoms that go unrecognized.

A

Women

39
Q

What are the 3 Goals of Acute MI Therapy?

A
  1. restore balance of myocardial oxygen supply/demand
  2. pain relief
  3. prevent complications that may arise post-MI
40
Q

Goals of Acute MI Therapy

How can the balance of mycardial demand/balance be restored?

A

reduction of ischemia by increasing supply of demand of MVO2

41
Q

Goals of Acute MI Therapy

What type of pain relief is the main focus?

A

reduction of angina symptoms

42
Q

Goals of Acute MI Therapy

What type of complications can be prevented post MI?

A
  • re-infarction
  • dangerous arrhythmias
  • congestive heart failure
  • death