CAD, ACS/MI, angina, and revascularization

Coronary artery disease

Narrowing/blockage of blood vessels that supply the heart

Primary cause of CAD

atherosclerosis

Atherosclerosis

Accumulation of lipids (plaque) in the lining of arterial blood vessel walls

CAD s/s

• Angina

• MI

• SOB

• Palpitations

• Indigestion

• Fatigue

Non-modifiable risk factors for CAD

• Age

• Male gender

• Family history/genetics

• PAD

• Diabetes mellitus

• Metabolic syndrome

Modifiable risk factors for CAD

• High cholesterol

• Smoking/tobacco use

• HTN

• Obesity

• Physical inactivity

• Unhealthy diet

Angina

Chest pain caused by inadequate blood flow to the myocardium

What happens to the heart muscle during angina

It does not receive enough oxygenated blood

Common triggers of angina

• Physical exertion

• Cold exposure

• Emotional stress

• Heavy meals

Types of angina

1. Stable

2. Unstable

3. Intractable (refractory)

4. Variant (prinzmetal’s)

5. Silent

Stable angina

Predictable, consistent chest pain that occurs with exercise, stress, or cold; relieves by rest/nitroglycerin

Unstable angina

New, worsening, more frequent chest pain that may occur at rest; does not respond to rest or nitroglycerin

Intractable (refractory) angina

Chronic, persistent, severe chest pain that doesn’t respond to treatment

What is intractable (refractory) angina often associated with

Advanced CAD

Variant (Prinzmetal’s) angina

Angina caused by coronary artery spasm; typically occurs at rest, especially at night

What medications usually relieve variant angina

Calcium channel blockers and nitrates

Silent angina

Reduced blood flow/O2 to the myocardium without noticeable chest pain / symptoms

Nitrate effects on angina

• Vasodilation

• Improves blood flow to heart

• Decreases myocardial O2 consumption

• Reduces preload + afterload

• Decreases BP

Are nitrates short acting or long acting

Can be either

Nitrate contraindications

• Recent ED medication use

• Hypovolemia/hypotension

• Bradycardia

• Increased intracranial pressure

• Severe anemia

Medications used for angina

• Short acting nitrates

• Beta blockers

• Calcium channel blockers

• Antiplatelets/anticoagulants

• Glycoprotein IIb/IIIa Agents

Beta blockers mechanism of action

Blocks beta-adrenergic sympathetic stimulation to the heart

Affects of beta blockers

• Decreased BP

• Slows conduction of impulses / decreases HR

• Decreases myocardial oxygen consumption

• Decreases contractility

Beta-blockers suffix

-olol

Beta blocker contraindications

• Severe bradycardia

• Heart block

• Hypotension

• Acute heart failure

Calcium channel blockers mechanism of action

Binds to calcium channels, blocking inward flow of calcium ions

Affects of calcium channel blockers

• Decreases SA/AV node activity

• Decreases HR

• Decreases contractility / workload

• Dilates smooth muscle of coronary arterioles

• Decreases myocardial oxygen demand

Calcium channel blockers suffix

-dipine

What lab value must be monitored with heparin

aPTT

aPTT measures…

amount of time it takes for a blood clot to form

What are thienopyridines?

Type of antiplatelet that blocks P2Y12 receptors on surface of platelets

What are glycoprotein IIb/IIIa agents

Type of antiplatelet that blocks GP IIb/IIIa receptors on surface of platelets (final common pathway for platelet aggregation, prevents fibrinogen adhesion)

most common thienopyridine

Clopidogrel (Plavix)

Example of glycoprotein IIb/IIIa

Abciximab (ReoPro)

Does angina cause permanent myocardial necrosis?

No

Acute coronary syndrome

Sudden, acute reduction in blood flow to the myocardium- often resulting in myocardial death

S/s of acute coronary syndrome

• Chest pain

• SOB

• N/V

• Anxiety

• Cool/pale/moist skin

What diagnostic test should be obtained for suspected ACS?

• ECG

• Blood test (troponin)

Within how many minutes should an ECG be obtained for suspected ACS?

Within 10 minutes

What ECG changes should be assessed for during suspected ACS?

• ST segment elevation or depression

• T-wave inversion

• Abnormal Q waves

What does STEMI stand for

ST- elevation myocardial infarction

What usually causes STEMI

Complete, near total blockage of one or more coronary arteries (significant damage)

What happens to heart muscle during STEMI

Prolonged lack of O2 to heart muscle causes myocardial tissue death

What does the ECG show during STEMI?

ST-segment elevation

What treatment does STEMI require?

Immediate reperfusion therapy

What does NSTEMI stand for

Non-ST-elevation myocardial infarction

What usually causes NSTEMI

Partial blockage of a coronary artery- smoke blood/oxygen still flows to heart

How much myocardial damage is associated with NSTEMI compared with STEMI

Less damage to myocardium

Does NSTEMI show ST-segment elevation on ECG?

No

What ECG changes may occur with NSTEMI?

• ST-segment depression

• T-wave inversion

Primary difference between STEMI and NSTEMI

STEMI involves complete coronary blockage, NSTEMI involves partial blockage

Which type of MI often involves the inner layer of the heart muscle?

NSTEMI

what imaging test can evaluate ventricular function during ACS?

Echocardiogram- especially TEE

What cardiac biomarker is assessed during ACS?

Cardiac troponin

What does elevated troponin indicate

Injury/damage to heart muscle

Which specific troponin markers indicate myocardial injury?

• Cardiac troponin I (cTnl)

• Cardiac troponin T (cTnT)

What does elevated CK-MB indicate

Possible acute myocardial infarction

What is myoglobin

Nonspecific marker that can be assess when evaluating possible MI

What can a negative myoglobin result help rule out?

MI

What diagnostic test should be obtained during initial ACS/MI management?

12 lead ECG

What cardiac biomarker should be obtained during initial ACS/MI management?

Troponin

What medication classes may be used to treat ACS/MI?

• Nitrates

• Beta-blockers

• Antiplatelets/anticoagulants

• Thrombolytics/fibrinolytics

Common anticoagulants used during ACS/MI treatment?

• Heparin / LMWH

• Factor Xa inhibitors

• Direct thrombin inhibitors

What are thrombolytics/fibrinolytics?

Medications that dissolve thrombi

What procedures may be performed to restore coronary blood flow during ACS/MI?

• Percutaneous coronary intervention

• Coronary artery bypass grafting

What is percutaneous coronary intervention?

Procedure used to open an occluded coronary artery via radial or femoral artery

What medications may be used for ongoing treatment after ACS/MI?

• Antiplatelets

• Statins

• Beta-blockers

• ACE inhibitors/ARBs

Types of PCI

1. Balloon angioplasty (percutaneous transluminal coronary angioplasty- PCTA)

2. Stent placement

What is PCTA/balloon angioplasty

Procedure using balloon-tipped catheter to widen a narrowed/blocked coronary artery; compresses fatty plaque against artery wall

What is a stent placement

Placement of a small, expandable metal stent inside a coronary artery, keeping it open (may be medicated)

What are possible complications of PCI?

• Coronary artery dissection

• Coronary artery perforation/rupture

• Restenosis (re-narrows)

• Cardiac arrest

• Vasospasm

What type of medication therapy is needed after ACS/PCI?

Dual antiplatelet therapy (DAPT) for at least 12 months

What medication may be administered IV for a vasovagal response after PCI?

Atropine

preferred access site for PCI

radial artery- lower risk of bleeding and vascular complications

CABG

Coronary artery bypass graft- restores blood flow to myocardium using other blood vessels to bypass obstructed coronary arteries

What are indications for CABG?

• Severe CAD

• Uncontrollable angina

• Failed PCI

What conditions may CABG help prevent or treat?

• CAD

• Angina

• Artery blockages

• Ischemia

• MI

• Cardiac arrest

• Dangerous arrhythmias

common vessels used for CABG

• Internal mammary arteries

• Great saphenous vein

possible complications of CABG

• Arrhythmias

• Neurological issues

• MI

• Acute kidney failure

• Lower extremity edema