Drug Treatment of Angina and Acute Coronary Syndromes

Question 1

What is resting coronary blood flow usually? How does that change during exercise?

Answer 1

At rest 200ml/min (4% of output)

During exercise Coronary blood flow increases by 3 -4 timex initial amount but cardiac output increases by 6 - 9 times. The reason for this is that coronary circulation is blocked during systole and can only occur during diastole

Question 2

How does oxygen demand increase from rest to exercise levels?

Answer 2

From 8 -> 70 ml O2/min per 100grams

Question 3

What does oxygen demand of the heart depend on?

Answer 3

Heart work which is determined by heart rate cardiac contractility and afterload.

Question 4

How can oxygen demand of myocardium be reduced?

Answer 4

Reducing heart rate and contractility through beta adrenoceptor blockers and calcium channel blockers.

Heart work can also be reduced by dilating peripheral vessels through the use of nitrates and calcium channel blockers (dihydropyridines)

Question 5

What are nitrates?

Answer 5

Peripheral Vasodilators

Question 6

How was glycerol trinitrate discovered as a vasodilator?

Answer 6

Workers with angina working in dynamite factories were reported to feel reduction in their symptoms on weekdays which returned on weekends.

Question 7

What are some examples of Nitrates?

Answer 7

Glyceryl trinitrate

Isosorbide dinitrate

Question 8

What compound do Glycerol trinitrate and isosobide dinitrate form?

Answer 8

NO (nitric oxide) which is a potent vasodilator

Question 9

What enzyme forms NO from GTN and isosorbide dinitrate?

Answer 9

Organic Nitrate Ester Reductase

Question 10

How is GTN taken in?

Answer 10

must be given via sublingual spray, IV, or transcutaneous patch.

Question 11

How is isosorbide mononitrate?

Answer 11

Can be taken orally through a sustained release tablet

Question 12

What is the limitation of using nitrates in the long term?

Answer 12

Tachyphylaxis: Effect loss over time (~24 hour). Should be taken intermittently as a result because the effect of NO is eventually lost

Question 13

What do antiplatelet drugs do?

Answer 13

Used in all forms of coronary artery diseases

Question 14

What are some examples of antiplatelet drugs?

Answer 14

Aspirin

Clopidogrel

Prasugrel; ticagrelor

Question 15

What are acute coronary syndromes?

Answer 15

Unstable states where underlying pathology is a ruptured plaque and accumulation of platelets on it.

Question 16

What are some examples of acute coronary syndromes?

Answer 16

Unstable angina

Non-ST elevation Acute MI

ST-elevation MI

Question 17

What are some early drug management strategies for acute coronary syndromes?

Answer 17

Analgesia (morphine for pain relief)

Limitation of infarct size (coronary thrombolysis)

Antiplatelet and anticoagulant therapy (aspirin / heparin)

Management of acute heart failure (ACE inhibitors, nitrates, diuretics)

Anti-arrhythmic drugs (eg. beta adrenoceptor blockage)

(ALAMA)

Question 18

What are some thrombolytic agents?

Answer 18

Streptokinase or altepase (decrease infarct size, complication, and mortality)

Question 19

What are the forms of antiplatelet and anticoagulant therapy?

Answer 19

Aspirin and clapidogrel (inhibit platelet aggreggation on coronary plaque)

LMW heparin prevents thrombotic and embolic complications

Question 20

What is the use of beta adrenergic blockers in early management of MI?

Answer 20

It limits infarct size

Helps pain

Question 21

How can coronary heart disease be managed in the long term?

Answer 21

By limiting adverse outcomes of myocardial infarction:

Cardiac remodelling (drugs administered to decrease load on heart are made to prevent hypertrophy from occuring resulting in more MI)

Recurrent myocardial infarction

Arrhythmia and sudden death

Question 22

What are the strategies to manage long term coronary heart disease?

Answer 22

Continued therapy:

Antiplatelet agents (reducing to single agent at 1 year)

Anticoagulants (where persisting thrombosis/embolism risk)

Beta 1 adrenergic blockage (to diminish risk of arrhthmia and cardiac remodelling)

Initiating new therapies must be done:

Risk factor management

Specific interventions

Question 23

How are risk factors managed in people with acute coronary artery diseases?

Answer 23

Diabetes control

Blood Pressure control

Lipids (statins, and reduced target concentrations with anyone that has a history of coronary heart disease)

Stop smoking

Question 24

What does a stemi look like on an ECG?

Answer 24

elevated T segment

Question 25

What is the initial management of a STEMI?

Answer 25

MOAN

Morphine (opioids)
Oxygen
Aspirin +clopidogrel
Nitrates

Question 26

What are the treatments of a STEMI after the initial management?

Answer 26

Primary cutaneous coronary intervention (using a deflated balloon)

Fibrinolytic therapy (streptokinase, alteplase)