Coronary Artery Disease

Question 1

What is the most important contributor to ECG/electrophysical changes of ischemia?

Answer 1

increased K+ leakage

Question 2

Why is aspirin given to patients with CAD?

Answer 2

Proven to reduce adverse events (MI, CVA, death); for those w/stable angina, unstable angina, acute MI, prophylaxis

Question 3

What is a drug that may be given for CAD if allergic to aspirin? Why is it not really used?

Answer 3

Ticlopidine

Causes Neutropenia and, rarely, TTP and has not shown a decrease in adverse events in pts w/ stable angina

Question 4

What are 2 thienopyridine antiplatelet agents that are more potent alternatives to aspirin? How do they work?

Answer 4

Clopidogrel (plavix)
Prasugrel
inhibits ADP binding to P2Y12 (inhibits platelet aggregation)

Question 5

In what patients are Clopidogrel and Prasugrel used? Which one has serious toxicity effects and is limited to use in healthy patients under 75?

Answer 5

Used in patients with stent placement as an antithrombotic

Prasugrel is very potent and assoc. with increased bleeding events

Question 6

Which drug is a ADP receptor blocker that inhibits platelet aggregation but has a black box warning against use with aspirin doses above 100mg?

Answer 6

Ticagrelor

Question 7

What is the mechanism of action and therapeutic use of Dipyridamole?

Answer 7

Mech: Dipyridamole inhibits the phosphodiesterase enzymes that normally break down cAMP (increasing cellular cAMP levels and blocking the platelet response to ADP); inhibits the cellular reuptake of adenosine into platelets, red blood cells and endothelial cells leading to increased extracellular concentrations of adenosine.
Use: patients with peripheral vascular disease if NO CAD present

Question 8

What are 4 effects of Angiotensin II?

Answer 8

1. vasoconstriction of arterioloes
2. increased GFR since caused more constriction in efferent arterioles of glomerulus
3. stimulates aldosterone release
4. stimulates ADH release

Question 9

What are the therapeutic uses of ACEI?

Answer 9

Often used as an add-on antihypertensive for anyone with chronic kidney disease/proteinuria, CHF, left ventricular hypertrophy, or post-MI (prevents left ventricular remodeling); reduces incidence of future CAD events, may reduce risk of diabetes

Question 10

What are 4 side effects and 4 contraindications of ACEIs?

Answer 10

SE: Dry cough (10-30%), angioedema, hyperkalemia (decreased aldosterone), hypotension
Contraindicated in: pregnancy, renal artery stenosis, hyperkalemia, and prior angioedema (no ARB allowed, either); caution in renal failure

Question 11

What are 3 therapeutic effects of Beta-blockers?

Answer 11

1. decrease O2 demand of heart (decrease contractility, HR)
2. Class II antiarrhythmics
3. increase AP duration / refractory period

Question 12

What are 4 contraindications to Beta-blocker use?

Answer 12

1. severe bradycardia
2. high degree AV block
3. sick sinus syndrome
4. unstable LV failure / acute HF
   (also relative contraindication is asthma, severe depression, peripheral vascular disease)

Question 13

What part of the vascular system predominates in Nitrates effects? What are the effects?

Answer 13

Venous dilation –> reduces ventricular preload –> reduces ventricular wall stress –> reduced O2 demand

Question 14

Which drugs can be used to treat Prinzmetal’s angina?

Answer 14

• Nitrates (causes dilation of coronary arteries and collateral vessels which increases O2 delivery and relieves coronary vasospasm)
• Ca+ channel blockers (dihydropyridines)

Question 15

What are 4 contraindications for use of Nitrates?

Answer 15

1. Hypertrophic cardiomyopathy
2. Severe aortic stenosis
   (since in both, need adequate preload to generate contraction force)
3. Significant hypotension
4. Use of phosphodiesterase inhibitors [viagra]

Question 16

Besides vasodilatory effects, what are 2 other actions of endothelial-derived NO?

Answer 16

1. inhibits platelet aggregation

2. inhibits leukocyte-endothelial interactions (anti-inflammatory)

Question 17

What are 4 side effects of Nitrates?

Answer 17

1. tolerance- need infrequent dosing or “nitrate free” periods to counteract
2. headaches (may diminish with long-term use)
3. hypotension
4. Bezold-Jarisch reflex (cardiac receptors sense decreased preload which causes increase in vagal input and sinus bradycardia)

Question 18

What is the mechanism of action of felodipine and others in its class?

Answer 18

(Ca+ channel blockers)
Interact with L-type voltage gated plasma membrane Ca channel –> decreased calcium entry into vascular smooth muscle cell, preventing contraction

Question 19

Which subclass of Ca+ channel blockers are vasoselective and which are more heart-specific? What are the consequences?

Answer 19

Dihydropyridines are vasoselective
–> dilate coronary arteries and arteriolar resistance vessels which may relieve coronary vasospasm and decrease arterial pressure
Non-dihydropyridines are heart-specific
–> true negative ionotropes, decrease firing of aberrant pacemaker sites, decrease HR

Question 20

Name a 1st generation dihydropyridine. Name 3 2nd generation. What is the difference?

Answer 20

1st generation: Nifedipine
2nd generation: Amlodipine, Felodipine, Isradipine
*1st generation not as selective and has some negative ionotropic effects

Question 21

What are 2 Non-dihydropyridines?

Answer 21

Verapamil

Diltiazem

Question 22

In what patients are Ca+ channel blockers contraindicated?

Answer 22

Contraindicated in overt decompensated heart failure, bradycardia, sinus node dysfunction, high-degree AV block

Question 23

What is the most common side effect of Ca+ channel blockers? What are 6 others?

Answer 23

• Most common- constipation
• hypotension
• worsening HF
• peripheral edema
• headache
• flushing
• bradycardia / AV block (non-dihydro’s)