Exam 2: Ischemic Heart Disease Spring 2024 Flashcards
1
Q
Risk Factors for Ischemic Heart Disease (IHD)
A
2
Q
2 most important risk factors for the development of atherosclerosis involving the coronary arteries are:
A
male gender and increasing age
3
Q
What percentage of patients will have a risk factor for ischemic heart disease?
A
30%
4
Q
What are the manifestations of IHD?
A
- Angina Pectoris
- Acute MI
- Sudden Death
- Dysrhythmias
5
Q
What is Angina Pectoris
A
Chest pain d/t imbalance between coronary blood flow and myocardial oxygen consumption.
6
Q
When does stable angina develop?
in the setting of what?
A
Stable angina typically develops in the setting of partial occlusion or significant (>70%) chronic narrowing of a segment of coronary artery.
7
Q
What is the most common cause of impaired coronary blood flow resulting in angina pectoris?
A
Atherosclerosis
- but it may also occur in the absence of coronary obstruction as a result of myocardial hypertrophy, severe aortic stenosis, or aortic regurgitation
8
Q
Angina pectoris reflects the intracardiac release of what two substances during ischemia?
A
- Adenosine
- Bradykinin
9
Q
What are the CV effects of adenosine and bradykinin release?
A
- Stimulate Cardiac nociceptors whose afferent neurons converge with the T1 to T5 sympathetic ganglia resulting in chest pain.
*** Slow AV conduction ** - Decrease Contractility
10
Q
How would a patient describe angina pectoris?
A
- Retrosternal chest discomfort
- Elephant sitting on their chest
- Chest discomfort radiates to left shoulder/jaw
- SOB and dyspnea
11
Q
Angina Pectoris affect which dermatomes?
A
- C8 to T4
12
Q
What factors can induce angina pectoralis?
A
- Physical exertion
- Emotional tension
- Cold weather
13
Q
Differentiate Chronic vs Unstable Angina
A
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
14
Q
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.
A
During myocardial ischemia, the standard 12-lead ECG demonstrates ST-segment depression that coincides with the anginal chest pain. This may be accompanied by transient symmetric T-wave inversion.
15
Q
What does a greater degree of ST segment depression on ECG mean in terms of CAD?
A
The greater the ST segment depression, the greater the likelihood of significant coronary artery disease.
16
Q
Specific diagnostic ECG changes for Acute MI during Exercise Stress Test:
- why is exercise stress test used for?
- is it always feasible?
A
Specific Changes: At least 1 mm of horizontal or downsloping ST-segment depression during or w/in 4 minutes after exercise
Uses: for detecting signs of MI and establishing the relationship to chest pain & exercise capacity
Feasible? not always feasible bc pt might not be able to exercise
Other Info from powerpoint:
Exercise ECG is less sensitive (overall sensitivity ∼75%) and specific in detecting ischemic heart disease than nuclear cardiology techniques.
17
Q
What does nuclear stress imaging assess?
A
*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
Thesize of the perfusion abnormality is the most important indicator of the significance of the coronary artery disease detected.
18
Q
What drugs can be administered to produce a rapid HR to create cardiac stress?
A
- Atropine
- Dobutamine
19
Q
What is the chemical tracer used to analyze cardiac blood flow?
A
- Thallium
20
Q
These drugs dilate normal coronary arteries but evoke no change in the diameter of atherosclerotic coronary arteries.
A
- Adenosine
- Dipyridamole
21
Q
What does an ECHO assess in IHD patients?
A
- Wall motion abnormalities
- Valvular functions
22
Q
Purpose of coronary angiography.
A
- Determines the location of occlusive disease
- Diagnose Prinzmetal (variant/spasm) angina
- Assess results of angioplasty/stenting
23
Q
Coronary angiography does NOT measure what?
A
- Stability of the plaque.
- Does not tell you when the plaque will rupture.
24
Q
Treatment for angina pectoralis? (Modifiable)
A
- Cessation of smoking
- Ideal body weight
- Low-fat, low-cholesterol diet (Statins)
- Regular aerobic exercise
- Treatment of hypertension
25
Patients are placed on statins when LDL levels are above ________ mg/dL.
160 mg/dL
*Providers would like a 50% reduction in LDL during statin therapy.*
26
Drug therapy for angina pectoralis
* Antiplatelet drugs
* Nitrates
* β-blockers
* Ranolazine
* CCB
* ACE inhibitors
27
Aspirin inhibits the enzyme _________. This results in the inhibition of ________, which plays an important role in platelet aggregation.
Aspirin inhibits the enzyme **COX-1**. This results in the inhibition of **thromboxane A2**, which stimulates activations for new platelets and is a potent vasoconstrictor.
28
Are the effects of aspirin reversible?
What is the dose for aspirin?
* No, COX-1 inhibition will last for the duration of platelet lifespan (7-14days)
* 75-325 mg/day
29
How do platelet glycoprotein IIb/IIIa receptor antagonists work?
What are examples of these antiplatelet drugs?
* Inhibit platelet aggregation
* Abciximab, Eptifibatide, Tirofiban
30
Thienopyridines (P2Y12 inhibitors)
examples
* Clopidogrel (Plavix)
* Prasugrel
31
Is Clopidogrel reversible?
No, Clopidogrel is irreversible.
32
MOA of Clopidogrel
* Blocks ADP from binding to P2Y12 receptor, which will inhibit platelet aggregation.
33
7 days after cessation of clopidogrel, ____% of platelets will have recovered normal aggregation function.
* 80%
34
Clopidogrel is a _______ that is metabolized into an active compound in the liver.
* Prodrug
35
________ % of patients taking clopidogrel demonstrate resistance or hyperresponsiveness.
* 10-20%
36
_________ can affect the enzyme that metabolizes clopidogrel to its active compound and thereby can reduce the effectiveness of clopidogrel.
* PPI
37
What drug has a similar mechanism action as clopidogrel, more predictable pharmacokinetics, and a higher risk of bleeding?
* Prasugrel
38
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.*
39
Nitrates are contraindicated with what heart conditions?
* Severe aortic stenosis
* Hypertrophic cardiomyopathy
*The decrease in preload in these conditions will not be good.*
40
Nitrates are synergistic with what drugs?
* β-Blockers and CCB
41
The only drug to prolong life in CAD patients and decrease the risk of death and reinfarction in MI pts.
β blockers
42
effects of B1 and examples
(atenolol, metoprolol, acebutolol, bisoprolol).
* ↓ HR
* ↑ Diastolic Time, ↑ Coronary Perfusion
* ↓ Myocardial contractility
* ↓ Myocardial O2 demand
43
Effects of β2 antagonist
(propranolol, nadolol).
* ↑ Bronchospasm
*Do not give this drug to asthma patients.*
44
__________ are uniquely effective in decreasing the frequency and severity of angina pectoris due to coronary artery spasm (Prinzmetal or variant angina).
* CCB
45
Effects of CCB
* Dilation of coronary artery
* ↓ Vascular smooth muscle tone
* ↓ Contractility
* ↓ O2 Consumption
* ↓ Systemic BP
46
CCB is not as effective as β-blockers in what aspect?
* β-blockers are more effective in decreasing the incidence of MI.
47
Functions of ACE-inhibitors
* Tx HTN
* Tx HF
* Cardioprotective
48
What does ANG II increase?
* Blood Pressure
* Myocardial Hypertrophy
* Interstitial Myocardial Fibrosis
* Coronary Vasoconstriction
* Inflammatory Response
49
What drug is used for coronary plaque stabilization?
Statins
50
What do statins decrease?
* Lipid oxidation
* Inflammation
* Matrix metalloproteinase
* Cell death
Reduces mortality noncardiac surgery and vascular surgery
51
When will revascularization be indicated?
* Revascularization by CABG or PCI is indicated when optimal medical therapy fails to control angina pectoris.
52
Revascularization is indicated when there is:
* Stenosis of left main coronary artery stenosis of **> 50%**
* Stenosis of epicardial coronary artery **>70%**
* Impaired EF **<40%**
53
When will CABG be preferred over a PCI?
* Significant left main CAD
* 3-vessel CAD
* DM pts who have 2 or 3-vessel CAD
54
What is ACS?
What is it caused by?
* Acute or worsening imbalance of myocardial oxygen supply to demand
* disruption of an atheromatous plaque
→ Coagulation cascade → Thrombin generation → Arterial occlusion
55
ACS → 12-Lead EKG → No ST-elevation → Troponin/CK-MB negative → ________
ACS → 12-Lead EKG → No ST-elevation → Troponin/CK-MB positive → ________
ACS → 12-Lead EKG → ST-elevation → Troponin/CK-MB postivie → ________
* Unstable Angina
* NSTEMI → MI
* STEMI → MI
56
Which substances contribute to thrombogenesis?
- Collagen, ADP, epinephrine, serotonin
- Thromboxane A2
- Glycoprotein IIb/IIIa receptors
- Fibrin deposit
Pathway:
- A platelet monolayer forms at the site of ruptured plaque, and chemical mediators like collagen, ADP, epinephrine, & serotonin stimulate platelet aggregation.
- The potent vasoconstrictor thromboxane A2 is released, which further compromises coronary blood flow.
- Glycoprotein IIb/IIIa receptors on the platelets are activated, which enhances the ability of platelets to interact with adhesive proteins & other platelets --> causes growth and stabilization of the thrombus.
- Further activation of coagulation leads to strengthening of the clot by fibrin deposition. This makes the clot more resistant to thrombolysis
57
Criteria chart for diagnosing an MI
58
What kind of plaques are more prone to rupture?
Vulnerable plaques w/ rich lipid cores and thin fibrous caps
59
Dx studies for ACS
* Troponin Lab
* Imaging
60
Levels of cardiac troponins increase within _____ hours after myocardial injury and remain elevated ?
troponin more specific than?
* 3 hours, 7-10 days
*Troponins are more specific than CK-MB*
61
Patients with typical ECG evidence of AMI do not require evaluation with echocardiography.
However, echocardiography is useful in patients with _____
LBBB or an abnormal ECG in whom the diagnosis of AMI is uncertain.
62
The primary goal in management of STEMI is
**to reestablish blood flow in the obstructed coronary artery as soon as possible
**
63
Drug therapy for ACS
-MONA
- P2Y12 inhibitors (clopidogrel)
- Platelet glycoprotein IIb/IIIa inhibitors
- Unfractionated heparin
- β -blockers
- ACE-inhibitors/ARBs
64
What drugs can be used for Reperfusion Therapy to restore normal antegrade blood flow?
When can these be initiated for IHD?
- tPA, Streptokinase, Reteplase, Tenecteplase
- 30–60 min of hospital arrival and within 12 hours of symptom onset.
65
Indications for PCI
- Contraindication to thrombolytic therapy
- Severe HF and/or pulmonary edema
- Symptoms present for 2 - 3 hours
- Mature clot
66
Indication for CABG
- Bad coronary anatomy
- Failed angioplasty
- Evidence of infarction-related ventricular septal rupture or mitral regurgitation
67
Causes Unstable Angina/NSTEMI
- Rupture or erosion of a coronary plaque
- Dynamic obstruction d/t vasoconstriction
- Worsening coronary luminal narrowing
- Inflammation
- Myocardial ischemia
68
Presentation of Unstable Angina/NSTEMI
- Angina at rest, lasting >10 minutes
- Chronic angina pectoris … more frequent and more easily provoked
- New-onset angina severe, prolonged, or disabling
69
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
- Aspirin, clopidogrel, prasugrel, or ticagrelor and heparin therapy (unfractionated heparin or LMWH
- **Thrombolytic therapy NOT indicated**
70
What is a PCI?
- Alternative to CABG
- 3 types: Balloon angioplasty, bare-metal stent, drug-eluting stent
- PCI will damage endothelium
71
Risk of PCI
* Thrombosis
* Bleeding
72
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
73
most significant independent predictor of stent thrombosis
P2Y12 inhibitor discontinuation
74
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
75
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
76
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)
77
Meds to continue before surgery for IHD pt.
- β blocker
- α2-agonist
- control hyperglycemia (<180 mg/dL)
78
Meds to d/c before surgery for PCI/IHD patients.
- ACE inhibitor (d/c 24 hours before surgery)
- Statins
- DAPT (continue ASA if possible)
79
What is given to a MI patient experiencing bradycardia in the OR?
Glycopyrrolate.
-Atropine is not used d/t the increased risk of dysrhythmias.*
80
Because several pathophysiologic mechanisms can trigger a PMI, it seems reasonable to think that multimodal therapy with _____may be more beneficial than treatment with any single drug
with β-blockers, statins, and insulin may be more beneficial than treatment with any single drug
81
Revised Cardiac Risk Index (RCRI)
82
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).
83
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**
84
Urgent Surgery
Urgent – life or limb would be threatened if the surgery did not proceed within 6 to 24 hours.
85
Time Sensitive Surgery
Delays exceeding 1 to 6 weeks would adversely affect patient outcomes
86
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)
87
**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
88
Anesthetic Goals for IHD
* Prevent myocardial ischemia
* Monitor for ischemia
* Treat ischemia
* Maintain BP and HR within the normal awake baseline (20%)
89
Anesthetic Preventions for IHD
* Persistent tachycardia
* Systolic HTN
* SNS stimulation
* Arterial hypoxemia
* Hypotension
90
DL should be less than ______ seconds.
15 seconds
91
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
92
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**
93
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**
94
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**
95
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.
96
volatile anesthetics may be beneficial bc...
may be detreimental bc...
beneficial decrease myocardial oxygen requirements and may precondition the myocardium to tolerate ischemic events
detrimental because they lead to a decrease in blood pressure and an associated reduction in coronary perfusion pressure.
