Ischemic Heart Disease (Exam II) Flashcards
What chemical mediators are released from ischemia that activate cardiac nociceptors?
Adenosine and Bradykinin
What is the path for cardiac pain signals to reach the spinal cord?
Cardiac nociceptors → Afferent Neurons → T1 - T5 SNS ganglia.
What is the CNS response to cardiac ischemia?
- ↓ AV conduction and thus ↓HR
- ↓ Contractility
3 physical inducers of angina
exertion
emotional tension
cold weather
Differentiate stable vs unstable angina.
- Stable - No change in chest pain severity or frequency in 2-mo period.
- Unstable - Increasing frequency and severity of chest pain.
Are cardiac biomarkers (troponin) present with unstable angina?
NO. If they were, that would be an MI.
What EKG abnormality is associated with old MI’s and/or current ischemia?
T-wave inversion
What is nuclear stress testing utilized for?
Coronary Perfusion assessment
What is the relationship between ST-segment depression and CAD.
The greater the degree of ST-segment depression, the greater the likelihood of significant artery disease
What determines the significance of CAD during a nuclear stress test?
Size of the perfusion abnormality
Arrows point to arrows of lesser perfusion.
What test can differentiate a new vs and old perfusion abnormality?
Nuclear Stress Testing
What nuclear stress test tracers are used with exercise?
Thallium and Technetium
less tracer, less blood flow
What nuclear stress test drugs are used without exercise?
Atropine
Dobutamine
Pacing
What test determines location of occlusive disease, diagnoses prinzmetal angina, and assess results of angioplasty/stenting?
Coronary angiography
When are adenosine and dipyridamole used with nuclear stress testing? Why?
Used after test to dilate normal, non-ischemic areas of the heart.
What test would be useful for imaging wall motion abnormalities or valvular function?
Echocardiography
What is Prinzmetal Angina?
Coronary Spasm
Differentiate old vs. new plaque
Old - lots of collateral blood flow
New - not a lot of collateral blood flow
How do you measure the stability of plaques?
You can’t
Non-pharmacologic tx for IHD
- Cessation of smoking
- Ideal body weight
- Low-fat/low-cholesterol diet
- Statins (LDL > 160 mg/dL)
- Aerobic exercise
- Tx for hypertension
What is the mechanism of action for aspirin?
COX-1 Inhibition → TXA2 inhibition → Plt aggregation inhibition.
Drug therapy for CAD?
ASA (75-325 mg/day)
…unless allergic, then: PY12 inhibitor (clopidogrel, prasugrel, or ticagrelor)
How can aspirin be reversed?
Trick question. It can’t be, platelets are damaged until they die and are replaced.
What is the mechanism of action of abciximab, eptifibatide, and tirofiban?
Platelet glycoprotein IIb/IIIa receptor antagonists
Inhibit platelet activation, adhesion, and aggregation.
What drugs (discussed in lecture) are P2Y12 inhibitors?
Clopidogrel and Prasugrel
What common drug class will antagonize P2Y12 inhibitors?
PPIs
How does Prasugrel compare to Clopidogrel?
More predictable pharmacokinetics but greater bleeding risk.
How do P2Y12 inhibitors work?
Inhibit ADP receptor P2Y12 and thus inhibit platelet aggregation.
What drug classes are synergistic with nitrates?
- β-blockers
- CCBs
When are nitrates contraindicated?
- Aortic Stenosis
- Hypertrophic Cardiomyopathy
What drug class is the only one proven to prolong life in CAD patients?
β-blockers
What properties do β-blockers have?
- Anti-ischemia
- Anti-HTN
- Anti-dysrhythmic
Which β blockers are cardioselective?
- Atenolol
- Metoprolol
- Acebutolol
- Bisoprolol
Which β blockers are non-selective?
- Propanolol
- Nadolol
What risk is associated with non-selective β blockers in asthma patients?
↑ risk of bronchospasm in reactive airway disease patients.
What drug class is uniquely effective is decreasing the severity/frequency of coronary vasospasm?
CCBs
What drug prevents ventricular remodeling, stablizes electrical activity of re-profused heart, and prevents the occurrence of reprofusion arrhythmias?
ACE Inhibitors
also treats hypertension, HF, and cardioprotective
Angiotensin II will increase what four things?
- Myocardial hypertrophy
- Interstitial myocardial fibrosis
- Coronary vasoconstriction
- Inflammatory responses
Is troponin or CK-MB more specific for myocardial injury?
Troponin
How soon with troponin start to increase after myocardial injury?
3 hours
lasts for 7-10 days
What are the 3 categories of acute coronary syndrome?
STEMI
non STEMI
Unstable angina
What diagnostic studies might indicate a myocardial infarction?
- EKG: abnormality (ex. LBBB)
- US: Regional wall motion abnormalities
What are indications for PCI treatment of an MI?
- Contraindicated tPa therapy
- Severe HF and/or pulm edema
- S/S for 2-3 hours
- Mature clot
When is CABG»_space;> PCI
- Significant left main coronary artery disease
- Three-vessel coronary artery disease
- Pt’s with DM who have 2 or 3 vessel CAD
What risks are associated with PCI (percutaneous coronary intervention) ?
- Endothelial destruction
- Bleeding*
- Thrombosis*
What is Dual Antiplatelet Therapy (DAPT) ?
- ASA w/ P2Y12
How long would one want to wait for elective surgery post angioplasty with no stenting?
2 - 4 weeks
How long would one want to wait for elective surgery post angioplasty with bare-metal stent placement?
At least 30 days (12 weeks preferable)
What is responsible for acute thrombus formation?
Vulnerable plaques
more prone to rupture w/rich lipid cores and thin fibrous caps
How long would you wait for elective surgery post angioplasty with drug-eluting stent placement?
At least 6 months (12 months if post ACS)
How long would you wait for elective surgery post-CABG?
At least 6 weeks (12 weeks preferable)
How long would you wait for elective surgery post angioplasty w/o stenting?
2-4 weeks
How long would you wait for elective surgery post bare metal stent placement?
At least 30 days, 12 weeks prefered
Is glycopyrrolate or atropine preferred for treatment of bradycardia?
Glycopyrrolate
Are β blockers or ACE-inhibitors continued peri-operatively?
β-blockers
Are β blockers or ACE-inhibitors discontinued 24 hours prior to surgery?
ACE inhibitors
Are statins or ACE-inhibtors discontinued 24hrs prior to surgery?
ACE-inhibtors
What components are worth 1 point on the Revised Cardiac Risk Index (RCRI) ?
What % risk of major cardiac events would be conferred by a RCRI score of 0 ?
0.4%
What % risk of major cardiac events would be conferred by a RCRI score of 1 ?
1.0%
What % risk of major cardiac events would be conferred by a RCRI score of 2 ?
2.4%
What % risk of major cardiac events would be conferred by a RCRI score of ≥3 ?
5.4%
What does 1 MET equal?
3.5mLO₂/kg/min
What drug is the preferred treatment for tachycardia?
Esmolol
What anticholinergic is the better option for treatment of bradycardia in CAD patients?
Glycopyrrolate > Atropine
What coronary artery would you expect to be effected from abnormalities noted on II, III, and aVF?
RCA
What coronary artery would you expect to be effected from abnormalities noted on I and aVL?
Circumflex artery
What coronary artery would you expect to be effected from abnormalities noted on V3 - V5?
LAD
Two biggest risk factors for developing atherosclerosis in the coronary arteries
Male gender
Increasing age
% of surgical patients w/IHD
30%
What diagnostic data is indicative of a myocardial infarction, select 2
- Detection of rise and/or fall of cardiac biomarkers
- Evidence of myocardial ischemia indicated by one of the following… Q waves, symptoms of ischemia, ST changes, etc.
What is pseudonormalization of the T wave?
Return of T-waves to an upright position after having chronically inverted T waves resulting from a previous MI
What is the primary goal for management of STEMI?
Reestablish blood flow in the obstructed coronary artery ASAP
time is tissue
Drug therapy for MI
MONA (Fentanyl better than Morphine)
P2Y12 inhibitors
IIb/IIa inhibitors
Unfractionated heparin
B blockers
RAAS
*ASA
In what time frame should tPA be initiated?
Within 30-60 min of hospital arrival
Within 12hrs of symptom onset
Presentation of unstable angina/STEMI
Angina at rest, lasting >10min
Chronic angina pectoris - a crescendo pattern of occurance
New-onset angina that is severe, prolonged, or disabling
What therapy is not indicated in unstable angina/NSTEMI?
Thrombolytic therapy - increases mortality
Treatment includes: bed rest, oxygen, analgesia, B-blockers, nitro, CCB, ASA, clopidogrel, prasugrel, ticagrelor, and heparin
Reendothelialization times….
Ballon angioplasty:
Bare-metal stent:
Drug-eluting stent:
Ballon angioplasty: 2-3 weeks
Bare-metal stent: 12 weeks
Drug-eluting stent: 1 year +
*drug-eluting has the longest reendothelialization time
thrombosis is major concern
What is the most significant independent predictor of stent thrombosis?
P2Y12 inhibitor discontinuation
Perioperative glucose goal
< 180 mg/dL
What are neuroendocrine stress responses that will cause increased cardiac oxygen demand in surgery?
↑HR
↑BP
Metabolic changes (↑ blood sugar)
….also postoperative shivering
What inflammatory responses caused by surgery might result in a perioperative MI?
Hypercoaguable state
Plaque rupture
What are examples of high-risk surgery?
- Abdominal aortic aneurysm
- Peripheral vascular operation
- Thoracotomy
- Major abdominal operation
What is a good pre-op MET score?
= or > 4 METS
raking leaves, gardening
What is a MET?
Metabolic Equivalent of Task
Emergent vs. Urgent vs. Time-Sensitive
Emergency - ☠️ or 🦵🏻 threatened if surgery doesn’t proceed within 6hrs
Urgent - ☠️ or 🦵🏻 threatened if surgery doesn’t proceed withing 6-24hrs
Time-sensitive - delays exceeding 1 to 6 weeks would adversely affect patient outcomes
In what kind of case would you need to skip a pre-op cardiac assessment?
Emergency case
How many days should elapse after a recent MI before noncardiac procedure?
60 days
in the absence of coronary intervention
What are examples of active cardiac conditions?
- Unstable coronary syndrome
- Unstable or severe MI
- Decompensated HF
- Severe valvular disease (aortic/mitral stenosis)
- Significant dysrhymias
- Age???
Maintain BP/HR within _______ % of normal awake baseline
20
Why should you avoid hyperventilation when trying to meet myocardial O2 needs?
Hypocapnia may cause coronary artery vasoconstriction
True/False - The use of nitrogen is contrindicated in patients with CAD
FALSE