Ischemic Heart Disease (Exam IV) Flashcards
Risk Factors for Ischemic Heart Disease (IHD)
What percentage of patients will have a risk factor for ischemic heart disease?
30%
What are the manifestations of IHD?
- Angina Pectoris
- Acute MI
- Sudden Death
*dysrhythmias
What is Angina Pectoris
Chest pain d/t imbalance between coronary blood flow and myocardial oxygen consumption.
Stable angina typically develops in the setting of partial occlusion or significant (>______%) chronic narrowing of a segment of the coronary artery.
- > 70%
Angina pectoris reflects the intracardiac release of what two substances during ischemia?
- Adenosine
- Bradykinin
What are the CV effects of adenosine and bradykinin release?
- Stimulate cardiac nociceptors whose afferent neurons converge with the T1 to T5 sympathetic ganglia, resulting in chest pain
- Slow AV conduction
- Decrease Contractility
improving balance between supply and demand
How would a patient describe angina pectoris?
- Retrosternal
- radiates to left shoulder/jaw/neck/ or arm (especially ulnar)
- radiate to any dermatome C8-T4
- SOB and dyspnea
short lasting, relieved by rest
Angina Pectoris affect which dermatomes?
- C8 to T4
What factors can induce angina pectoralis?
- Physical exertion
- Emotional tension
- Cold weather
Differentiate Chronic vs Unstable Angina
Chronic stable: Chest pain that does NOT change in frequency or severity in a 2-month period
Unstable: Chest pain increasing in frequency and/or severity without an increase in cardiac biomarkers
- at rest chest pain lasting >10 min
During myocardial ischemia, the standard 12-lead ECG demonstrates ST-segment _______ that coincides with the anginal chest pain. This may be accompanied by transient symmetric _________ inversion.
ST-segment depression
T-wave inversion
What does the Exercise Stress Test evaluate on the EKG?
- Degree of ST-segment depression
The greater the degree of ST-segment depression, the greater the likelihood of significant coronary artery disease.
What does nuclear stress imaging assess?
- Assesses coronary perfusion (greater sensitivity than other tests)
- Tracer activity in perfused vs ischemic areas
- Estimates LV systolic size and function
- Differentiates new perfusion abnormality vs. old MI
The size of perfusion abnormality will correlate with the significance of CAD.
What drugs can be administered to produce a rapid HR to create cardiac stress?
- Atropine
- Dobutamine
and pacing
What is the chemical tracer used to analyze cardiac blood flow?
Thallium
Technetium
the greater the coronary lesion, the greater reduction in tracer in that area
These drugs dilate normal coronary arteries but evoke no change in the diameter of atherosclerotic coronary arteries.
Adenosine
Dipyridamole
What does an ECHO assess in IHD patients?
- Wall motion abnormalities
- Valvular functions
*not indicated for typical ECG AMI… BUT useful for LBBB or abnoraml ECG where AMI is uncertain
Purpose of coronary angiography.
- Determines the location of occlusive disease
- Diagnose Prinzmetal (variant/spasm) angina
- Assess results of angioplasty/stenting
Coronary angiography does NOT measure what?
- Stability of the plaque.
- Does not tell you when the plaque will rupture.
Treatment for angina pectoralis?
- Cessation of smoking
- Ideal body weight
- Low-fat, low-cholesterol diet (Statins)
- Regular aerobic exercise
- Treatment of hypertension
Patients are placed on statins when LDL levels are above ________ mg/dL.
160 mg/dL
Providers would like a 50% reduction in LDL or <70 mg/dL during statin therapy.
Drug therapy for angina pectoralis
- Antiplatelet drugs
- Nitrates
- β-blockers
- Ranolazine
- CCB
- ACE inhibitors
Aspirin inhibits the enzyme _________. This results in the inhibition of ________, which plays an important role in platelet aggregation.
COX-1
thromboxane A2: stimulates activations for new platelets and is a potent vasoconstrictor.
Are the effects of aspirin reversible?
What is the dose for aspirin?
- No, COX-1 inhibition will last for the duration of platelet lifespan (7 days)
- 75-325 mg/day
How do platelet glycoprotein IIb/IIIa receptor antagonists work?
What are examples of these antiplatelet drugs?
Inhibit platelet activation, adhesion, aggregation
- Abciximab, Eptifibatide, Tirofiban
Name 2 Thienopyridines (P2Y12inhibitors) drugs
- Clopidogrel (Plavix)
- Prasugrel: higher risk of bleeding
Is Clopidogrel reversible?
No, Clopidogrel is irreversible.
MOA of Clopidogrel
Blocks ADP from binding to P2Y12 receptor, which will inhibit platelet aggregation.
7 days after cessation of clopidogrel, ____% of platelets will have recovered normal aggregation function.
80%
Clopidogrel is a _______ that is metabolized into an active compound in the liver.
Prodrug
metabolized into active compound in the liver
________ % of patients taking clopidogrel demonstrate resistance or hyperresponsiveness.
10-20%
_________ can affect the enzyme that metabolizes clopidogrel to its active compound and thereby can reduce the effectiveness of clopidogrel.
PPI
What drug has a similar mechanism action as clopidogrel, more predictable pharmacokinetics, and a higher risk of bleeding?
Prasugrel
How does Nitrate treat myocardial ischemia?
- Decrease the frequency, duration, and severity of angina pectoris.
- Dilate Coronary Arteries and Collaterals
- Decrease peripheral vascular resistance
- Decrease Preload
- Anti-thrombotic effects
Nitrates will increase the amount of exercise required to produce ST-segment depression
Nitrates are contraindicated with what heart conditions?
- Severe aortic stenosis
- Hypertrophic cardiomyopathy
The decrease in preload in these conditions will not be good
Nitrates are synergistic with what drugs?
- β-Blockers and CCB
greater anti-anginal effects
The only drug to prolong life in CAD patients and decrease the risk of death and reinfarction in MI pts.
β blockers
anti-ischemic
anti-hypertensive
anti-dysrhythmic
Effective Beta Blockade is resting HR 50-60 BPM
Effects of β1 antagonist (atenolol, metoprolol, acebutolol, bisoprolol).
- ↓ HR
- ↑ Diastolic Time, ↑ Coronary Perfusion
- ↓ Myocardial contractility
- ↓ Myocardial O2 demand
Effects of β2 antagonist (propranolol, nadolol).
- ↑ Bronchospasm
Do not give this drug to asthma patients.
__________ are uniquely effective in decreasing the frequency and severity of angina pectoris due to coronary artery spasm (Prinzmetal or variant angina).
- CCB
Effects of CCB
- Dilation of coronary artery
- ↓ Vascular smooth muscle tone , decrease coronary spasms
- ↓ Contractility
- ↓ O2 Consumption
- ↓ Systemic BP
CCB is not as effective as β-blockers in what aspect?
- β-blockers are more effective in decreasing the incidence of MI/mortality
CCB second line for people that dont respond to BB
- CBB less resonse to BP, more sensitive to HR
- CCB dilate coronary arteries
Functions of ACE-inhibitors
- Tx HTN
- Tx HF
- Cardioprotective
What does ANG II increase?
- Blood Pressure
- Myocardial Hypertrophy
- Interstitial Myocardial Fibrosis
- Coronary Vasoconstriction
- Inflammatory Response
What drug is used for coronary plaque stabilization?
Statins
What do statins decrease?
- Lipid oxidation
- Inflammation
- Matrix metalloproteinase
- Cell death
reduce mortality in noncardiac surgery and vascular surgery
When will revascularization be indicated?
- Revascularization by CABG or PCI is indicated when optimal medical therapy fails to control angina pectoris.
Revascularization is indicated when there is:
Stenosis of left main coronary artery stenosis of > _____%
Stenosis of epicardial coronary artery > _______%
Impaired EF < ______%
Stenosis of left main coronary artery stenosis of > 50%
Stenosis of epicardial coronary artery >70%
Impaired EF <40%
When will CABG be preferred over a PCI?
Significant left main CAD
3-vessel CAD
DM pts who have 2 or 3-vessel CAD
What is ACS?
What is it caused by?
- Acute or worsening imbalance of myocardial oxygen supply to demand
- Plaque rupture → Coagulation cascade → Thrombin generation → Arterial occlusion
ACS → No ST-elevation → Troponin/CK-MB negative → ________
ACS →No ST-elevation → Troponin/CK-MB positive → ________
ACS →ST-elevation → Troponin/CK-MB postivie → ________
- Unstable Angina
- NSTEMI → MI
- STEMI → MI
STEMI occurs when coronary blood flow decreases abruptly. This decrease in blood flow is attributable to acute thrombus formation. This creates a local environment that favors ________.
When plaques rupture, various chemical mediators such as ______, _______, _______, and _______ stimulate platelet aggregation.
The potent vasoconstrictor ________ is released, which further compromises coronary blood flow.
- Thrombogenesis
- Colloagen, ADP, Epi, Serotonin
- Thromboxane A2
_________ receptors on the platelets are activated, which enhances the ability of platelets to interact with adhesive proteins and other platelets and causes growth and stabilization of the thrombus.
Further activation of coagulation leads to the strengthening of the clot by _______. This makes the clot more resistant to thrombolysis.
- Glycoprotein IIb/IIIa
- Fibrin
Criteria chart for diagnosing an MI
Dx studies for ACS
- Troponin Lab
- Imaging
Troponin is a cardiac-specific protein and biochemical marker for AMI.
Levels of cardiac troponins increase within _____ hours after myocardial injury and remain elevated for 7–10 days.
- 3 hours
Troponins are more specific than CK-MB
the greater the troponin, the greater the MI
Patients with typical ECG evidence of AMI do not require evaluation with echocardiography.
However, echocardiography is useful in patients with _____ or an abnormal ECG in whom the diagnosis of AMI is uncertain.
- LBBB
ECHO will demonstrate regional wall motion abnormalities in most patients with AMI
Drug therapy for ACS
- MONA
- P2Y12inhibitors (clopidogrel, prasugrel, ticagrelor)
- Platelet glycoprotein IIb/IIIa inhibitors
- Unfractionated heparin
- β-blockers
- ACE-inhibitors/ARBs
What drugs can be used for Reperfusion Therapy to restore normal antegrade blood flow?
When can these be initiated for IHD?
Thrombolytics: break up the fibrin
- tPA, Streptokinase, Reteplase, Tenecteplase
- 30–60 min of hospital arrival and within 12 hours of symptom onset.
Indications for PCI
- Contraindication to thrombolytic therapy
- Severe HF and/or pulmonary edema
- Symptoms present for 2 - 3 hours
- Mature clot
PCI > thrombolytics
Indication for CABG
- Bad coronary anatomy
- Failed angioplasty
- Evidence of infarction-related ventricular septal rupture or mitral regurgitation
Causes Unstable Angina/NSTEMI
- Rupture or erosion of a coronary plaque: non-occlusive
- Dynamic obstruction d/t vasoconstriction (vasospasm): prinzmetal-variant angina, cold temperature, cocaine use
- Worsening coronary luminal narrowing
- Inflammation: vasculitis
- Myocardial ischemia: sepsis, fever, tachycardia, anemia
Presentation of Unstable Angina/NSTEMI
chronic vs acute
- Angina at rest, lasting >10 minutes
- Chronic angina pectoris … more frequent and more easily provoked
- New-onset angina severe, prolonged, or disabling
Treatment of Unstable Angina/NSTEMI.
What treatment is NOT indicated?
- Bed rest, oxygen, analgesia, and β-blocker therapy
- Sublingual or IV nitroglycerin
- Calcium channel blockers: especially if ischemia persists w/ BB and nitrates
- Aspirin, clopidogrel, prasugrel, or ticagrelor and heparin therapy (unfractionated heparin or LMWH)
*Fonaparinux: specifically factor X1 inhibitor
- Glycoprotein IIb/IIIa agents
***Thrombolytic therapy is NOT indicated: only for STEMI
What is a PCI?
- Alternative to CABG
- 3 types: Balloon angioplasty, bare-metal stent, drug-eluting stent
- damage of endothelium
Risk of PCI
- Thrombosis
- Bleeding
Re-endothelialization Time of the following:
Balloon Angioplasty
Bare-Metal Stent
Drug-Eluting Stent
- Balloon Angioplasty: 2-3 weeks
- Bare-Metal Stent: 12 weeks
- Drug-Eluting Stent: 1 year
Important to stay on dual antiplatelet therapy (DAPT) - ASA w/ Plavix
When do you want to d/c DAPT before surgery?
Clopidogrel or Ticagrelor
Prasugrel
ASA
- 5 days - Copidogrel or Ticagrelor
- 7 days – Prasugrel
- Continue ASA if possible
Time to wait for Elective Surgery for the following procedures:
Angioplasty w/o stent:
Bare-metal stent placement:
Coronary artery bypass grafting:
Drug-eluting stent placement:
- Angioplasty w/o stent: 2-4 weeks
- Bare-metal stent placement: 30 days - 12 weeks
- Coronary artery bypass grafting: 6-12 weeks
- Drug-eluting stent placement: 6-12 months
Pre-operative Assessment for Cardiac Procedures
- Determine the presence of risk factors
- Evaluate METs (>4)
- Co-existing non-cardiac disease
- Physical Exam
- Specialize testing (EKG)
Meds to continue before surgery for IHD pt.
- β blocker
- α2-agonist
- Statins
- control hyperglycemia (<180 mg/dL)
Meds to d/c before surgery for PCI/IHD patients.
- ACE inhibitor (d/c 24 hours before surgery)
- DAPT (continue ASA if possible)
What is given to a patient experiencing bradycardia in the OR?
Glycopyrrolate.
Atropine is not used d/t the increased risk of dysrhythmias.
Revised Cardiac Risk Index (RCRI)
What is MET?
What does 1 MET equal?
What do you want a patient’s MET to be above?
- Metabolic equivalent of task - tool used to assess cardiopulmonary fitness.
- 1 MET = 3.5 mL of O2/kg/min
- > 4 METs (Can climb at least one flight of stairs).
What is considered an emergency surgery?
- Life or limb would be threatened if the surgery did not proceed within 6 hours or less
- Proceed directly to emergency surgery w/o pre-op cardiac assessment
Urgent Surgery
Urgent – life or limb would be threatened if the surgery did not proceed within 6 to 24 hours.
Time Sensitive Surgery
Delays exceeding 1 to 6 weeks would adversely affect patient outcomes
Active Cardiac Conditions that can cancel a surgery.
- Unstable coronary syndromes
- Unstable or severe angina
- Decompensated HF
- Severe valvular heart disease
- Significant dysrhythmias
- Age = Fraility (depends)
Unstable Coronary Syndrome
It is suggested that more than _____ days should elapse after a recent MI before noncardiac surgery is undertaken (in the absence of coronary intervention).
- 60 days
Anesthetic Goals for IHD
- Prevent myocardial ischemia
- Monitor for ischemia
- Treat ischemia
- Maintain BP and HR within the normal awake baseline (20%)
Anesthetic Preventions for IHD
- Persistent tachycardia
- Systolic HTN
- SNS stimulation
- Arterial hypoxemia
- Hypotension
DL should be less than ______ seconds.
15 seconds
Anesthetic Considerations for IHD Patients
Severe LV function drug induction consideration:
Why avoid neuraxial anesthesia in DAPT pt?:
What type of NMBD to avoid:?
- Severe LV function: Consider Opioid only induction
- Avoid neuraxial anesthesia can cause bleeding.
- Avoid NMBD that can release excessive histamine: atracurium
Lead: I and aVL
Coronary Artery Responsible for Ischemia:
Area Involved:
Lead: I and aVL
Coronary Artery Responsible for Ischemia: Circumflex
Area Involved: Lateral aspect of LV
Lead: V3-V5
Coronary Artery Responsible for Ischemia:
Area Involved:
Lead: V3-V5
Coronary Artery Responsible for Ischemia: LAD
Area Involved: Anterolateral aspect of LV
Lead: II, III, aVF
Coronary Artery Responsible for Ischemia:
Area Involved
Lead: II, III, aVF
Coronary Artery Responsible for Ischemia: RCA
Area Involved: RA, RV, SA & AV Node, Inferior Aspect of LV
In general, myocardial _______ is represented by ST depression and symmetric T-wave inversion (TWI), while myocardial ________ may be indicated by ST elevation with or without T wave changes.
In general, myocardial ischemia is represented by ST depression and symmetric T-wave inversion (TWI), while myocardial injury may be indicated by ST elevation with or without T-wave changes.
Major cause of death with IHD?
dysrhythmias
Two most important risk factors for delevopment of atherosclerosis?
male gender
increasing age
What are causes of impaired coronary blood flow? (4)
*athhlersclerosis
myocardial hypertrophy
severe AS
Aortic regurgitation
What is ST segment depression indicative of?
subendocardial ischemia
- can be accompanied by T-wave inversion
What is pseudonormalization of the T-wave?
patients with chronically inverted T-wave from propr MI may show return of normal upright T-waves during myocardial ischemia
How is a positive exercise stress test indicated?
atleast 1mm of horizontal or downslope of ST depression during or within 4 minutes after exercise
What is less sensitive in detecting ischemic heart disease… Exercise ECG or nuclear cariology?
exercise ECG only 75% indicative
What are vulnerable plaques?
most likely to rupture forming an occlusive thrombus
-its a thin fibrous cap and a large lipid core containing lots of macrophages
NO test to measure stability of plaques
if patient suspected or definitely has AMI… and they are allergic to aspirin, what drug should they take?
P2Y12 inhibitor
- clopidogrel
- prasugrel
- tricagrelor
people on long term nitrates (isosorbide) dont resond well to….?
sublingual nitro
may need to give IV nitro instead
What B1 commonly used in anesthesia?
*labetolol
- metoprolol: great for contractility but not HR
- Esmolol: great fr HR but not contractility
what do people 24 hours post cardiac admission/surgery need?
BB
ACEi vs. CCB/BB
ACEi very cheap
How many pateients have new-onset or change in angina pattern during the 30 days post AMI
2/3
How many patients especially with elederly and DM have no or mild pain during AMI
1/4th
Neuraxial blockade is not advised in patients receiving DAPT due to ____?
spinal hematoma
during the placement of the catheter and removal
What does S3 gallop or rales indicated
LV dysfunction
