Cardiovascular Anesthesia Pt. 1 (Exam III) Flashcards
What are some risk factors for CAD?
- Male
- Age
- ↑ cholesterol
- HTN
- Smoking
- DM
- Obesity
- Sedentary lifestyle
- Genetics
- Personality/Stress
Angina is an imbalance between myocardial _____ and ______.
demand & supply
What is the pain pathway of angina?
Partially occluded coronary artery
→ Adenosine, bradykinin, lactic acid release
→ nociceptive receptors w/ afferent neurons to upper five thoracic sympathetic ganglia
→ thalamic & cortical stimulation = pain
Which spinal levels are responsible for myocardial pain receptors?
Thoracic 1 - 5
What are the two types of angina?
- Chronic (stable) angina = no change in pain intensity or duration over 2 months
- Unstable = pain at rest or increasing in severity/frequency
What two EKG changes are often indicative of subendocardial ischemia?
- ST segment depression
- Transient T-wave depression
What is the name of the point where the transition from the QRS to the ST-segment occurs?
J-Point
What are the three types of ST-Segment depression?
- Up-sloping
- Down-sloping
- Horizontal
What type of ST-segment depression is most likely to be related to coronary disease?
Horizontal ST depression
More ST depression = ______ likelihood of significant CAD.
higher
What diagnostic test assesses coronary perfusion and has greater sensitivity for ischemia than exercise testing?
Nuclear stress test
Which tracers are used with nuclear stress testing?
Thallium & Technetium
What would an absent uptake of nuclear stress test tracers indicate?
Old MI (fibrous tissue)
What would an significant uptake of nuclear stress test tracers indicate?
normal circulation
What would a decreased uptake of nuclear stress test tracers indicate?
Perfusion abnormality
How is non-exercise nuclear stress testing done?
Induced tachycardia w/
- Atropine
- Dobutamine
- Pacing
Which two drugs are coronary dilators used in nuclear stress testing?
Adenosine
Dipyridamole
What type of coronary plaque is considered unstable?
Large lipid core with thin cover
Very likely to rupture.
What does aspirin inhibit?
COX-1
Thromboxane A2
How long does the effect of platelet inhibition due to aspirin last?
For the life of the platelet (irreversible)
What is the “lifespan” of a human platelet?
7 - 10 days
How does Clopidogrel (Plavix) work?
Inhibition of ADP receptor (P2Y12)
What drug class can greatly change the effects of Plavix due to enzyme inhibition?
PPI’s
What drug is similar to clopidogrel in the following:
- Requires P450 enzyme for conversion from prodrug to active metabolite
- Inhibits ADP P2Y12
Prasugrel (Effient)
What are the pros & cons of Prasugrel vs Plavix?
Prasugrel Pros:
- Rapidly absorbed
- Faster onset
- Less individual variability
Cons:
- Higher risk of bleeding (much more potent)
What two conditions were mentioned in lecture as contraindications for nitrate administration?
- Hypertrophic Cardiomyopathy
- Aortic Stenosis
Nitrates have a synergistic effect with what drug classes?
β blockers & CCB’s
What are the effects of nitrates?
- Subendocardial artery dilation
- ↓ SVR
- ↓ afterload
- ↓ myocardial O₂ consumption
Which two cardiac disease processes necessitate a maintenance of a high afterload?
- Hypertrophic Cardiomyopathy
- Aortic Stenosis
Can nitrates be given around the clock?
No, 8 - 12 hours of the day need to be nitrate free.
Sensitization occurs w/ around the clock therapy.
What is the principal drug for stable angina?
β blockers
How do β blockers improve coronary perfusion?
- ↓ myocardial O₂ demand
- ↑ diastole time
In what scenarios are β blockers contraindicated?
- Severe bradycardia
- Sick sinus syndrome
- Severe Asthma
- 2ⁿᵈ & 3ʳᵈ degree heart block
- Uncontrolled CHF
What common cardiac drug class will mask the signs of hypoglycemia?
β blockers
What are the SCIP protocol measures for β blockers?
- If already on β blocker, must receive dose within 24 hours of surgery
- If not on β blocker, do not initiate unless 1-4 weeks out from non-cardiac surgery.
What type of calcium channels do CCB’s bind to?
L-type Ca⁺⁺ channels
Where are the effects of L-type Ca⁺⁺ channel blockade seen?
- Smooth muscle
- Cardiac Myocytes
- SA/AV nodes
Are β blockers or CCB’s more effective in prevention of MI?
β blockers
What type of angina are CCBs most useful for?
Prinzmetal’s Angina
What is Prinzmetal’s angina?
Vasospasm related angina (not related to atherosclerosis)
Angiotensin II promotes inflammatory response and what other deleterious cardiac effects?
- Atheroma formation
- Coronary vasoconstriction
- Myocardial hypertrophy
ACE inhibitors are indicated for patients with CAD and what other concurrent diseases?
- HTN
- LV dysfunction
- DM
What antihypertensive is held within 24 hours of anesthesia? Why?
ACE Inhibitors (compounds hypotension from anesthesia).
What is the mortality of STEMI without early reperfusion therapy? How about with reperfusion therapy?
- 20% without
- 6.5% with reperfusion therapy
What is MONA?
Morphine
Oxygen
Nitrates
Aspirin
According to lecture, what is an NSTEMI?
No ST-elevation but:
- New-onset severe and/or prolonged angina
- Angina at rest for more than 20 min
How are NSTEMI’s diagnosed?
- ↑ biomarkers
- ST depression and/or T-wave inversion w/ pain.
What is the major difference in treatment of STEMI vs NSTEMI?
No thrombolytics (tPa) for NSTEMI patients
What is the most common cause of death in acute MI?
Cardiac Dysrhythmias
If ventricular tachycardia is asymptomatic, how can it be treated?
Lidocaine and/or amiodarone
What are the most common atrial dysrhythmias?
Afib / Aflutter
What decreases the occurrence of atrial dysrhythmias during/after MI?
Thrombolytics
What type of MI is commonly seen with sinus bradycardia?
Inferior wall MI
When does pericarditis typically occur after an MI?
1 - 4 days post MI
What position worsens pericarditis pain?
Lying down
Diffuse ST-segment changes would likely indicate ________.
Pericarditis
How is pericarditis treated?
- ASA
- Indomethacin
- Steroids
If pericarditis becomes chronic after an MI, it is called ________ syndrome.
Dressler’s Syndrome
What can occur from ischemic injury causing rupture of the papillary muscles?
Mitral regurgitation
An MI in which wall makes mitral regurgitation much more likely?
Inferior wall MI (can result in papillary muscle rupture).
What is the treatment for Mitral Regurgitation?
- ↓ LV Afterload (diuretics, nitrates)
- ↑ Coronary perfusion (IABP, consider valve repair)
In order to have significant cardiogenic shock, usually ____ % or more of the myocardium must be infarcted.
40% or more
Where is the tip of a IABP positioned?
Just below the Left Subclavian artery
When does an IABP inflate & deflate?
- Inflate during ventricular diastole
- Deflate just prior to ventricular systole
What are contraindications to IABP placement?
- Severe aortic insufficiency
- Aortic Aneurysm
- Severe PAD
- Severe Coagulopathy
What are the possible complications of IABP?
- Limb Ischemia
- Aortic Dissection
- Hemorrhage
- Helium Emboli
- Infection
KNOW 12 LEAD EKG DIAGNOSES
When are bare-metal coronary stents more appropriate than drug-eluting stents?
In patients who need urgent surgeries
What is inhibited by drug-eluting stents?
- Clotting
- Neointimal Hyperplasia
What makes drug-eluting stent placement much more risky?
If antiplatelet therapy is discontinued in 1st year
What is the general risk with coronary stenting?
- Mechanically opening a blood vessel injures the endothelium and increases the risk of thrombosis
How long does re-endothelialization occur (according to current DAPT guidelines) with the following:
- Angioplasty
- Bare-metal stents
- Drug-eluting stents
- 2 weeks
- 6 weeks
- 3 months
What pathologies have shown increased mortality in studies in patients who are who are on DAPT?
- Spinal Cord pathologies
- Aneurysm
- Prostatectomy
Look up DAPT & Neuraxial Interventions
What are the indications for CABG surgery?
- Medical therapy failure
- LM > 50% obstructed
- EF <40% w/ significant disease
- 3 or more diseased vessels
When is emergency CABG surgery indicated?
- Failed angioplasty
- MI septal rupture
- MI mitral regurgitation
- Perforated coronary artery
- Cardiogenic shock
