Ischemic Heart Disease I Flashcards
Risk factors for cardiovascular disease?
- Male
- Age
- High cholesterol
- HTN
- Smoking
- DM
- Obesity
- Inactivity
- Genetics
- Stress
Main cause of ischemic heart disease?
Imbalance of myocardial oxygen supply and demand due to occluded coronary artery.
Name the metabolites released from an occluded artery.
- Adenosine
- Bradykinin
- Lactic Acid
Description of Angina
- Substernal pain
- May radiate to neck or arm
- Lasts minutes
- Relieved by rest or NTG
Differentiate between chronic (stable) angina and unstable angina
- Chronic: Does not change in intensity or duration over 2+ months.
- Unstable: Rest pain or increased severity/frequency
Name ways to diagnosis CAD. What is the gold standard?
- Subjective Symptoms
- EKG
- Nuclear imaging,
- Echocardiography
- Coronary angiography (gold standard)
What EKG pattern correlates with Subendocardial ischemia coinciding with chest pain?
- ST segment depression
- Transient T-wave inversion
What are the various types of ST segment depression?
Which one has a higher correlation to angina?
- Upsloping
- Downsloping
- Horizontal (more likely to be angina related)
Negative Exercise EKG test makes chance of ________ vessel disease unlikely.
Three Vessel Disease
What test assess coronary perfusion and provides a greater sensitivity for ischemia than exercise testing?
Nuclear Stress Imaging
Tracers in nuclear imaging?
- Thallium
- Technetium
What does significant tracer uptake in nuclear stress imaging mean?
- Normal circulation
- Increase circulation with exercise
What does decrease tracer uptake in nuclear stress imaging mean?
Perfusion abnormality
What does absent uptake in nuclear stress imaging mean?
Old MI
When is pharmacologic stress testing (Nuclear Imaging w/o Exercise) used?
- Musculoskeletal issues
- Patient is deconditioned
- PVD
What drugs/methods will produce tachycardia to create cardiac stress in Nuclear Imaging?
- Atropine
- Dobutamine
- Pacing
What drugs are given in Nuclear Imagining to dilate coronary arteries?
- Adenosine
- Dipyridamole (Persantine)
Coronary dilation will be indicated by increased tracer.
No dilation of atheroscolerotic arteries indicated by decreased tracer.
Purpose of echocardiography?
- Detects wall motion abnormalities (site of ischemia)
- Assess valve function
- Assess EF
Indications for coronary angiography?
- Diagnosing ischemia
- Assessing survivors of sudden cardiac death
- Evaluating revascularization
What prognosis can be made from a coronary angiography?
- Extent of atherosclerosis
- Left Ventricular Function (EF)
- Stability of plaque
Describe a “vulnerable plaque” seen in a coronary angiography.
- Large Lipid Core
- Thin fibrous capsule/cover
- More likely to rupture and occlude
5 main drug classes used to treat for ischemic heart disease?
- Anti-platelets
- ACE inhibitors.
- β-blockers
- CCB
- Nitrates
MOA of Aspirin
Inhibits COX-1 → Inhibits thromboxane A2 → Inhibits platelet aggregation.
- Aspirin Dose: 75-325 mg/day
- Decrease the risk of a cardiac event
MOA of Clopidogrel (Plavix)
- Inhibits ADP receptor (P2Y12) to reduce platelet aggregation
- Active metabolite variable in action (20% variability)
Clopidogrel is used in patients intolerant of ASA
Clopidogrel’s effectiveness is decreased with this drug.
- PPI
- PPI inhibit the enzyme that metabolizes clopidogrel from prodrug to active
MOA of Prasugrel (Effient)
- Inhibits ADP receptor (P2Y12) to reduce platelet aggregation
- Requires P450 enzyme to convert from prodrug to active metabolite
Key differences between Prasugrel and Clopidogrel?
- Prasugrel is more rapidly absorbed
- Prasugrel has faster onset of action
- Prasugrel has less variability, more predictable
- Prasugrel is more potent (higher risk of bleeding)
Nitrates’ primary effect?
- Dilate coronary arteries
- Decrease peripheral vascular resistance
- Reduce afterload
- Lower myocardial oxygen demand
Nitrates effect is synergistic with what drugs?
- β-blockers
- CCB
Nitrates are contraindicated in patients with these cardiac conditions
- Hypertrophic cardiomyopathy
- Aortic Stenosis
- Afterload needs to be maintained in these conditions, nitrates will reduce the afterload
Why do we need an 8-12 hour window of “nitrate-free” zone?
- To prevent nitrate tolerance
- Give time to restore receptor’s sensitivity to nitrates (usually bedtime to morning)
Principle drug for stable angina
β-blockers
Purpose of beta-blockers in ischemia?
- Decrease myocardial oxygen demand
- Prolong diastole (↑coronary perfusion)
- Decrease re-infarction
Name β1-blockers drugs
- Atenolol (commonly used)
- Metoprolol (commonly used)
- Bisoprolol
- Acebutolol
Conditions where β-blockers are contraindicated
- Severe bradycardia
- Sick sinus syndrome (SSS)
- Severe reactive airways
- 2nd/3rd degree heart block
- Uncontrolled CHF
How does β-blockers mask the signs of hypoglycemia?
β-blockers mask Sx of hypoglycemia by blocking the SNS responses, such as tachycardia, tremors, and sweating, which are typical warning signs of low blood sugar.
Three properties of β-blockers
- Anti-anginal
- Anti-hypertensive
- Anti-dysrhythmic
What does the Surgical Care Improvement Project (SCIP) say about patients receiving β-blockers?
- Surgery patients on β-blocker prior to admission must receive dose w/i 24 hr prior to case
- No indication for acute initiation of β-blocker therapy …must initiate 1-4 weeks prior to non-cardiac surgery
Name the specific channels CCB inhibit.
L-type calcium channels located in smooth muscles, cardiac myocytes, and SA/AV nodes
Common CCB used
- Amlodipine (Norvasc)
- Nicardipine (Cardene)
CCB are most useful in treating this type of angina.
Prinzmetal’s ( Variant) Angina
Role of calcium channel blockers?
- Decrease vascular tone
- Dilate coronary arteries
- Improve supply/demand
CCB are potent vasodilators which can lead to these effects.
- Hypotension
- Peripheral Edema
- HA
What does ANG II promote?
- Inflammatory response
- Atheroma formation
- Coronary vasoconstriction
- Myocardial hypertrophy
ACE inhibitors are indicated for patients with CAD and _______, _______, and/or ________.
- HTN
- LV dysfunction
- DM
Consideration of ACE-inhibitors with anesthesia.
- ACE inhibitors SIGNIFICANTLY increases hypotensive effects of anesthesia.
- HOLD 24 HOURS before surgery
Patho of acute coronary syndrome
Focal disruption of a plaque → coagulation cascade → thrombus formation → Imbalance of O2 supply/demand → ACS
STEMI mortality rate with early perfusion vs without
- Early perfusion: 6.5%
- Without: 15-20%
What is the prognosis of a STEMI dependent on?
- LV Function
- Residual ischemia
- Ventricular dysrhythmias
What is the first biomarker to peak with an MI?
When does this biomarker peak?
- Myoglobin
- Peaks at 4-12 hours
If a patient came in 3 days after his chest pain? What biomarkers will be elevated if this patient had an infarction?
- LDH
- Troponin
Order the cardiac biomarkers that peak first to last
- Myoglobin
- Total CK
- CK-MB
- Troponin
- LDH
Treatment for STEMI
- MONA
- Anti-platelet
- β-blockers
- Reperfusion (thrombolytics, angioplasty, stent, CABG)
EKG Diagnosis of a NSTEMI
- ST-depression and/or deep T-wave inversion WITH pain
- Elevated biomarkers
Treatment for NSTEMI
- O2
- β-blocker
- Antiplatelet vs Heparin
- Consider early interventions
These type of drugs should be avoided in NSTEMI, can increase mortality.
- No thrombolytics for NSTEMI patients
- Thrombolytics are only for complete occlusions
When does V-fib occur after an MI.
Treatment.
- 1st four hours
- Defib w/ 200-300 Joules
Asymptomatic VT can be treated with what drugs?
- Lidocaine
- Amiodarone
- Treat symptomatic VT with cardioversion
Treatment for A-flutter/A-fib if patient is unstable.
What can be given for rate control.
- Cardioversion for unstable patients
- β-blockers for rate control
MI to what region of the heart will result in Sinus Brady?
Treatment for Sinus Brady.
- Inferior Wall
- Atropine or Pacing to treat sinus brady
When does pericarditis occur after an MI?
- 1-4 days post MI
- 10-15% of patients
Sx of Pericarditis
- Pain is worse laying down
- Pain from inspiration d/t pericardial friction rub
- ST-segment changes through 12-lead EKG
Treatment for Pericarditis
- Self resolves with time
- Treat pain and inflammation w/ ASA, indomethacin, steroids
Describe Dressler’s Syndrome
- Pericarditis that appears weeks to months after an acute MI
- Immune mediated pericarditis
How does MI cause mitral regurgitation?
Ischemic injury to papillary muscle will cause them to rupture
Treatment for mitral valve regurgitation
- LV afterload reduction (diuretics, nitrates)
- IABP to improve coronary perfusion
- MR = FAST, FULL, FOWARD
If the mitral valve regurgitation is severe what can it lead to?
- Pulmonary Edema
- Cardiogenic Shock
Cardiogenic shock is usually developed if more than ____-% of the myocardium is infarcted.
40%
Treatment for Cardiogenic Shock
- Reverse mechanical complications (pap ruptures, MR)
- Improve BP (levo, vaso, dopamine, dobutamine)
- Treat pulmonary edema (diuretics, vent)
- Restore coronary flow (IABP/LVAD)
How does a IABP work?
- Inflates in diastole to improve coronary perfusion
- Deflates before systole to reduce afterload and promotes forward flow
When will IABP be contraindicated?
- Aortic Insufficiency
- Aortic Aneurysm
- Severe PVD
- Severe Coagulopathy
Complications to IABP
- Limb ischemia
- Aortic dissection
- Hemorrhage from insertion site
- Helium emboli
- Infection
High Lateral Leads:
Inferior Leads:
Septal Leads:
Anterior Leads:
Lateral Leads:
High Lateral Leads: Lead I, aVL
Inferior Leads: Lead II, Lead III, aVF
Septal Leads: V1, V2
Anterior Leads: V3, V4
Lateral Leads: V5, V6
The circumflex artery is typically associated with which lead?
- Lateral Leads
- Lead I, aVL, V5, and V6
The right coronary artery is typically associated with which lead?
- Inferior Leads
- Lead II, Lead III, and aVF
The LAD is typically associated with which lead?
- Septal and Anterior Leads
- V1 to V4
- Inverted T-waves seen in V1 to V4 suggesting a NSTEMI
- Myocardial Ischemia to LAD
Please note that these interpretations of the 12-Lead EKG reflect my own analysis and have not been independently verified for accuracy
- Widespread ST-elevation throughout
- Reciprocal ST-depression in aVR
- Pericarditis
Please note that these interpretations of the 12-Lead EKG reflect my own analysis and have not been independently verified for accuracy
- ST-elevation in Lead II, Lead III, and aVF
- Reciprocal ST depression in aVL
- Inferior STEMI affecting right coronary artery
Please note that these interpretations of the 12-Lead EKG reflect my own analysis and have not been independently verified for accuracy
Which type of PTCA will have a lower incidence of restenosis?
Drug-eluting stents (DES)
Although DES have a low rate of stenosis, the risk significantly increases if antiplatelet therapy is d/c in the first year.
When will bare metal stents be appropriate?
More appropriate in patients needing urgent surgeries
How long does re-endothelialization take for angioplasty, bare metal stents, and drug-eluting stents?
- Angioplasty: 2-3 weeks
- Bare metal stents: 12 weeks
- Drug-eluting stents: 1 year
DAPT recommendation length for angioplasty, bare metal stents, and drug-eluting stents?
- Angioplasty: 2 weeks
- Bare metal stents: 6 weeks
- Drug-eluting stents: 3 months
Adverse effects of Stent Placement
- Thrombosis if DAPT is d/c (↑risk w/ DM, low EF)
- Bleeding from operation (increased mortality in spinal cord, aneurysm, and prostatectomy surgery)
DAPT Recommendations and Neuraxial Interventions
Indications for Routine/Scheduled CABG
- Medical therapy fails
- Left main lesion > 50% stenosis
- EF <40% with significant disease
- Three or more vessels with disease
Indications for EMERGENCY CABG
- Failed angioplasty
- MI-related septal rupture
- MI-related mitral regurgitation
- Perforated coronary arteries during stenting
- Cardiogenic shock
