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
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. (without increase in cardiac biomarkers)
What other systems may cause chest pain not related to IHD?
Cardiac- pericarditis
Vascular- aortic dissection, PE, P HTN
pulmonary- pleuritis, pneumo
GI- GERD, gallbladder, pancreatitis
musculoskeletal- trauma, cervical disk disease
infections- herpes zoster
psychological- panic disorder (hardest to rule out)
How long do troponin levels remain elevated for?
bumps in 3-4 hours, elevated for up to 2 wks
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
ST segment depression is characteristic of what?
subendocardial ischemia
At least _____ of horizontal or downscoping ___________________ during or within _____ minutes after exercise is indicative of ________
1mm, ST segment depression, 4 minutes, significant CAD
Exercise EKG (stress test) is useful for what?
detecting s/sx of myocardial ischemia
often combined with imaging studies to demonstrate areas of ischemic myocardium
What is nuclear stress testing utilized for?
Coronary Perfusion assessment
Is nuclear stress test or exercise testing more sensitive for detection of IHD?
nuclear stress imaging
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?
Tina Turner getting stressed
Thallium and technetium
What nuclear stress test drugs are used without exercise?
Atropine
Dobutamine
Pacing
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
What is coronary angiography used for?
Prinz Logan Does Not Armwrestle
determines location of occlusive disease
diagnose prinzmetal angina
assess results of angioplasty/stenting
does NOT measure stability of plaque
What is the treatment for angina pectoris?
cessation of smoking
IBW
low fat, low-cholesterol diet (Statin)
regular aerobic exercise
treatment of HTN
What is the mechanism of action for aspirin?
COX-1 Inhibition → TXA2 inhibition → Plt aggregation inhibition.
What is the function of TXA2?
stimulates activation of new platelets as well as increases platelet aggregation
How can aspirin be reversed?
Trick question. It can’t be, platelets are damaged until they die and are replaced.
What are examples of IIb/IIIa receptor antagonists?
abciximab, eptifibatide, tirofiban
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.
clopidogrel is a ______
prodrug
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 are the consequences of taking a nitrate? (5)
decrease frequency, duration, and severity of angina
dilate coronary arteries and collaterals
decrease SVR
decreases preload
potential anti-thrombotic effects
What drug class is the only one proven to prolong life in CAD patients?
β-blockers
decreases risk of death and reinfarction in MI pt
What properties do β-blockers have? (3)
- Anti-ischemia
- Anti-HTN
- Anti-dysrhythmic
Which β blockers are cardioselective?
- Atenolol
- Metoprolol
- Acebutolol
- Bisoprolol
- “BAMA”
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, but not as effective as BB in decreasing incidence of myocardial reinfarction
ACE inhibitors inhibit what?
the conversion of ANG I–> ANG II
Angiotensin II will increase what four things?
Feminists Insulted Vibrant Hobos
- Myocardial hypertrophy
- Interstitial myocardial fibrosis
- Coronary vasoconstriction
- Inflammatory responses
How do statins help in IHD
-coronary plaque stabilization
-decreases: lipid oxidation, inflammation, matrix metalloproteinase, and cell death
-reduces mortality, non cardiac surgery, and vascular surgery
When is re-vascularization indicated?
failure of medical therapy
>50% L main coronary artery
>70% epicardial coronary artery
impaired EF <40%
When is CABG preferred over PCI?
significant L main disease, 3-vessel CAD, DM who have 2-3 vessel CAD
How does acute coronary syndrome begin?
focal disruption of an atheromatous plaque
Triggers the coagulation cascade
thrombin generation
arterial occlusion by a thrombus
The majority of STEMI’s are caused by what?
thrombotic occlusion of coronary artery
What are the chemical mediators of thrombogenesis?
collagen, ADP, epi, 5-HT3
TXA2
Glycoprotein IIb/IIIa receptors
fibrin deposit
What diagnostic data is indicative of MI
Is troponin or CK-MB more specific for myocardial injury?
Troponin
How soon with troponin start to increase after myocardial injury?
3 hours
What diagnostic studies might indicate a myocardial infarction?
- EKG: abnormality (ex. LBBB)
- US: Regional wall motion abnormalities
What is the primary goal in management of STEMI?
reestablish blood flow in the obstructed coronary artery as soon as possible
What is the drug therapy for a STEMI?
MONA
If ASA cannot be used, use P2Y12 inhibitors
platelets, glycoprotein IIb/IIIa inhibitors
unfractionated heparin
Beta blockers (not given if heart block is present)
RAAS
thrombolytics included in reperfussion therapy?
tPA, streptokinase, reteplase, tenecteplase
–>restores normal integrate blood flow
_____is >thrombolytic therapy
PCI
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
Presentation of unstable angina
angina at rest, lasting >10minutes
Chronic vs new-onset angina pectoris
chronic: more frequent and more easily provoked
new-onset: severe, prolonged, or disabling
What drug therapy is not indicated in unstable angina or NSTEMI
thrombolytics
What risks are associated with PCI (percutaneous coronary intervention) ?
- Bleeding
- Thrombosis
-endothelial injury
When is a CABG indicated for reperfusion?
coronary anatomy not conducive to stents
failed angioplasty
evidence of infarction related ventricular septal rupture or mitral regurgitation
How long until reendothelialized after…
balloon angioplasty?
bare metal stent placement?
drug-eluting stent?
2-3 weeks
up to 12 weeks
a full year or longer
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)
How long would one want to wait for elective surgery post angioplasty with drug-eluting stent placement?
At least 6 months (12 months if post ACS)
ACS= acute coronary syndrome
How long would one want to wait for elective surgery post-CABG?
At least 6 weeks (12 weeks preferable)
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
KNOW THIS CHART according to Cornelius
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% (considered LOW risk if risk is <1%)
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% (considered ELEVATED risk if >1%)
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
Urgency of surgery criteria
emergency: life or limb threatened if surgery does not proceed within 6 hours
urgent: life or lim threatened if surgery does not proceed within 6-24 hours
time-sensitive- delays exceeding 1-6 weeks could adversely affect pt outcomes
____ days should elapse after a recent MI before non-cardiac surgery is performed
60
Surgical patients with significant risk who should avoid surgery
US SAD
unstable or severe angina
decompensated heart failure
severe valvular disease
significant dysrhythmias
Age- considered a risk factor when associated with frailty
we should avoid _______________ our patients because __________may cause coronary artery constriction
hyperventilating, hypocapnia
What are the effects of volatiles in patients with IHD?
may be beneficial by decreasing myocardial oxygen requirements, making the heart able to tolerate ischemic events
could also be detrimental by decreasing BP and coronary artery perfusion
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 do we use to treat hypotension?
sympathomimetics or a fluid bolus
What coronary artery would you expect to be effected from abnormalities noted on II, III, and aVF?
RCA (RA, RV, SA/AV node, inferior LV)
What coronary artery would you expect to be effected from abnormalities noted on I and aVL?
Circumflex artery (lateral LV)
What coronary artery would you expect to be effected from abnormalities noted on V3 - V5?
LAD (anterolateral LV)
How many leads should we monitor the heart with?
2 leads has been the standard, but 3 leads may improve ability to detect ischemia
What are the 2 most important risk factors for the development of atherosclerosis involving the coronary arteries?
Male gender and increasing age
What are the 1st manifestations of IHD?
angina pectoris, acute MI, sudden death
(dysrhythmias major cause of sudden death)
What are all of the risk factors for IHD
Male gender,
increasing age,
hypercholesterolemia
HTN
Cigarette smoke
DM
Obesity
Sedentary lifestyle
Genetics/family history
Stable angina develops in the setting of partial or significant occlusion. significant occlusion is indicated by what percent of occlusion
70%
What is the physiology of angina pectoris?
Release of adenosine and bradykinin stimulate cardiac nociceptive and mechanosensitive receptors whose afferent neurons converge with the upper five thoracic sympathetic ganglia and somatic nerve fibers in the spinal cord and ultimately produce thalamic and cortical stimulation that results in the typical chest pain of angina pectoris.
What substances produce chest pain and also slow the AV conduction and decrease cardiac contractility?
adenosine and bradykinin
What is the most common cause of impaired coronary blood flow resulting in angina pectoris?
atherosclerosis
How is angina diagnosed?
retrosternal chest pain, pressure, heaviness
radiates to any dermatome from C8-T4- often the neck, L shoulder/arm, jaw, and occasionally to the back or down both arms (especially the ulnar surfaces)
SOB
lasts several minutes
What are examples that may induce angina
physical exertion, emotional tension, cold weather (shoveling snow)
