Ischemic Heart Disease Flashcards
Why is PCI preferred over thrombolytic therapy for severe heart failure?
Because they will probably end up needing assistive devices anyways (balloon pump, impella, etc)
Indications for Percutaneous Coronary Intervention for a STEMI:
- If there is contraindications to thrombolytic therapy
- Severe HF and/or pulmonary edema
- Symptoms present for 2-3 hours
- Mature clot
The combination of what 2 things provide the maximum chance of achieving normal antegrade coronary blood flow and decreases the need for a subsequent revascularization procedure?
Intracoronary stents and antiplatelet drugs
What is the ideal timeframe to perform an angioplasty for a STEMI?
Within 90 minutes of arrival and within 12 hours of symptom onset
What situations would need a CABG for a STEMI?
- Coronary anatomy that inhibits PCI
- Failed angioplasty
- Evidence of infarction-related ventricular septal rupture or mitral regurg
Causes of unstable angina/NSTEMI:
- Reduction of myocardial oxygen supply
Rupture or erosion of a coronary plaque - Dynamic obstruction due to vasoconstriction
- Worsening coronary luminal narrowing
- Inflammation
- Myocardial ischemia
Presentation for 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
Why is chronic angina pectoris more easily occuring in unstable angina?
Because of the narrowing of the vessel so there’s less blood flow
What is the acute phase of treatment for unstable angina/NSTEMI directed at?
Decreasing myocardial oxygen demand and stabilizing culprit lesion
What is the longer term phase of treatment for unstable angina/NSTEMI directed at?
Prevention of disease progression and future plaque erosion and rupture
Treatment for unstable angina/NSTEMI:
- Bedrest, oxygen, analgesia, and B-blocker therapy
- Sublingual or IV nitroglycerin
- Calcium channel blockers
- Aspirin, clopidogrel, prasugrel or ticagrelor and heparin therapy
_____ _____ is not indicated in UA/NSTEMI and has been shown to increase mortality.
Thrombolytic therapy
Risks for PCI:
- Thrombogenesis from vessel injury
- Bleeding/rupture
- Can increase ischemia (completely occluding artery for a short period of time)
What are the 3 types of PCI?
- Balloon angioplasty
- Bare-metal stent
- Drug eluding stent
Reendothelialize after balloon angioplasty-
2-3 weeks
Reendothelialize after bare-metal stent placement-
12 weeks
Reendothelialize after drug-eluting stent:
A full 1 year or longer
____ ____ discontinutation is the most significant independent predictor of stent thrombosis
P2Y12 inhibitor
Most common combination of meds for dual antiplatelet therapy:
Aspirin with P2Y12 inhibitor
How soon do you D/C DAPT before surgery to reduce bleeding risk?
- Clopidogrel or ticagrelor - 5 days
- Prasugrel - 7 days
- Continue ASA if possible
Timing of the operation after PCI
What are important parts of the pre-op assessment for ischemic heart disease?
- Determine presence of risk factors
- Evaluate METs
- Co-existing non-cardiac disease
- Physical exam
- Specialized testing
Ischemic heart disease medications:
- Beta blockers
- Alpha 2 agonists (decrease sympathetic outflow, BP and HR)
- ACE Inhibitors
- Statins
- DAPT
- Control hyperglycemia
Revised Cardiac Risk Index:
Components of RCRI:
Functional Capacity:
It is suggested that more than __ days should elapse after a recent MI before noncardiac surgery is undertaken
60
Active cardiac conditions that may increase the risk of perioperative adverse cardiac events:
- Unstable coronary syndromes
- Unstable or severe angina
- Decompensated heart failure
- Severe valvular heart disease
- Significant dysrhythmias
- Age
What are risk factors for ischemic heart disease? (1st 2 are most important)
Male Gender
Increasing Age
Hypercholesterolemia
HTN
Smoker
DM
Obesity
Sedentary lifestyle
Genetics
____% of surgical patients have ischemic heart disease
30%
What are the first manifestations of ischemic heart disease?
- Angina pectoris
- Acute MI
- Sudden death (dysrhythmias)
Stable angina develops in partial occlusion or >____% narrowing of coronary artery
70%
How is stable angina characterized?
Chest pain relieved by rest
What vital sign changes are associated with decreased coronary blood flow? What about if you are under GA?
- ↓BP and ↑ HR
- EKG changes when under anesthesia
What causes Angina Pectoris?
Imbalance between coronary blood flow and myocardial O2 consumption
________ is the most common cause of impaired coronary blood flow resulting in angina
Atherosclerosis
What mediators are released with angina and what do they do?
- Release of adenosine and bradykinin
-Stimulate cardiac nociceptors→ afferent neurons coverage T1-T5 sympathetic ganglia→ produce thalamic and cortical stimulation causing chest pain
-Slow AV conduction and decrease cardiac contractility (attempting to balance O2 supply and demand)
What are common signs and symptoms of angina pectoris
- Retrosternal chest pain, pressure, heaviness
-Radiates to neck, left shoulder, left arm, or jaw - SOB, Dyspnea
Which group of people have atypical presentation of angina pectoris?
- Diabetics
- Females
Me ;)
What are some things discussed in class that can cause chest pain?
- Physical exertion
- Emotional tension
- Cold weather
Describe chronic stable angina:
Chest pain that does NOT change in frequency or severity in 2-month period
What causes chronic stable angina?
Distal occlusions
What are characteristics of unstable angina?
Angina at rest (>10min)
Unstable angina is chest pain increasing in frequency and/or severity without increase in cardiac biomarkers
What are some chest pain differential diagnoses?
(I’m sorry I simply could not type this one)
What diagnostic tests can be done when someone presents with chest pain?
- 12 lead EKG
- Exercise stress test
- Nuclear stress imaging
- Echo
- Coronary Angiography
What EKG changes correlate with likelihood of significant coronary artery disease?
Greater ST depression = more significant CAD
Which test has the greatest sensitivity for detecting ischemic heart disease?
Nuclear stress imaging
What does the nuclear stress imagining assess?
- Coronary perfusion
- Size of perfusion abnormality
- Estimates LV systolic size/fxn
- Differentiates new from”Old” MI
What tracers are used for nuclear stress imaging?
- Thallium
- Atropine, Dobutamine, Pacing
- Adenosine, Dipyridamole
What diagnostic study is used to diagnose Prinzmetal angina?
Coronary angiography
What does and area of ischemia look like in an echo?
Wall motion abnormalities
Which diagnostic for chest pain can determine the location of occlusive disease?
Coronary angiography
(does not measure stability of plaque)
Non-pharmacologic treatment for angina?
- Stop smoking
- Lose weight
- Low fat/low CHO diet
- Regular exercise
- HTN treatment
Primary drug therapy for angina pectoris:
- ASA
-Platelet glycoprotein IIb/IIa receptor antagonists - P2Y12 inhibitors
- Prasugrel (short term in cathlab)
- Nitrates
- Beta blockers
- CCB
- ACE inhibitors
- Statins
All patients with suspected AMI should receive ______.
Aspirin
if allergic should get P2Y12 inhibitor
MOA of aspirin and dose:
- Irreversibly inhibits COX-1 (thromboxane A2)
- 75 – 325 mg/day
MOA of glycoprotein IIb/IIa receptor antagonists:
- IV, more effective than ASA (short half lives)
- Inhibit platelet activation, adhesion, and aggregation
What is a typical platelet lifespan?
7-14 days
MOA of Clopidogrel (Plavix):
- Inhibits ADP receptor P2Y12 and platelet aggregation
- Irreversible, platelet life span
-D/C ~ 80% of platelets recover to normal function - Prodrug: variability from person to person
What class of drug is Prasugrel? When is it used?
P2Y12 inhibitor (Thienopyridines)
-More predictable pharmacokinetics than plavix
- Higher risk of bleeding (given short term in cath lab)
What are characteristics of Nitrates?
-Decrease frequency, duration, and severity of chest pain
-Increase exercise to produce ST-segment depression
- Dilate coronary arteries and collaterals
- Decrease peripheral vascular resistance
- Decreases preload
- Potential anti-thrombotic effects
What are drug interactions with Nitrates?
- Synergistic with beta blocker and CCBs
What diseases are nitrates contraindicated?
-Aortic stenosis
- Hypertrophic cardiomyopathy
What class of drug is the only drug to prolong life in CAD patients?
Beta blockers
Do you stop beta blockers preop?
No, want to continue them or stop and give something similar (esmolol)
Which drugs are B1 selective beta blockers?
-Atenolol
-Metoprolol
- Acebutolol
- Bisoprolol
Beta 2 adrenergic blockers:
-Propranolol
- Nadolol
What are the benefits of beta 1 blockade for angina?
- Lower HR
- Increase diastolic time
- Decrease myocardial contractility
- Decrease myocardial O2 demand
Which patients do you want to avoid beta 2 blockers in?
Reactive airway → increase risk of bronchospasm
What type of angina are CCB appropriate for?
- Prinzmetal/ Variant Angina
- Uniquely effective for decreasing frequency/severity of spasm
What is the MOA of CCBs?
- Dilated coronary arteries
-Decreases vascular tone - Decreases contractility
- Decreases O2 consumption
- Decreases Systemic BP
What do ACE inhibitors treat?
- Hypertension
- Heart failure
- Cardioprotective
ACE inhibitors block conversion of angiotensin I to angiotensin II. What does angiotensin II do?
- Increases myocardia hypertrophy
- Increases interstitial myocardial fibrosis
- Increases coronary vasoconstriction
- Increases inflammatory responses
What is the purpose of statins?
- Coronary plaque stabilization
- Decreases lipid oxidation
- Decreases inflammation
- Decreases matrix metalloproteinase
- Decreases cell death
What drug reduces mortality in noncardiac surgery and vascular sugery?
Statins
When is revascularization (PCI) indicated?
- Meds fail
- > 50% L main coronary artery
- > 70% epicardial coronary artery
- Impaired EF <40%
When is CABG preferred treatment over PCI?
- 50% LAD occulsion
- Coronary artery stenosis 70& occluded
- 3 vessel coronary artery disease
- DM pt who have 2-3 vessel CAD
What is acute coronary syndrome?
Acute or worsening imbalance of myocardial oxygen supply to demand → leads to chest pain
What are causes of acute coronary syndrome?
- Atheromatous plaque
- Coagulation cascade
- Thrombin generation
- Arterial occlusion
What are the 3 categories of acute coronary syndrome based on 12-lead ECG and cardiac biomarkers?
- STEMI
- Non STEMI
- Unstable angina (cardiac makers - )
What causes an MI?
- Coronary blood flow decreases abruptly
- Acute thrombus formation
What is the process of thrombus formation?
-Collagen, ADP, epinephrine, serotonin
- Thromboxane A2
- Glycoprotein IIb/IIIa receptors
- Fibrin deposit
When is the term myocardial infarction used?
When there is evidence of mycardial necrosis
What diagnostic data is indicative of myocardial infarction:
- Rise/fall of cardiac biomarkers (trop) AND evidence of myocardial ischemia indicated by at lease one of the following:
-Symptoms of ischemia
-ECG changes (new ST, T changes LBBB)
- Pathologic Q waves
- Imaging evidence of new loss of viable myocardium or new regional wall motion
- ID of intracoronary thrombus by angiography
When does troponin increase?
Increase within 3 hours after myocardial injury
What cardiac lab test is more specific for cardiac damage than CK-MB?
Troponin
When would fentanyl be given over morphine for patient having an MI?
Fentanyl over morphine to avoid hypotension
Drug therapy for Acute coronary syndrome:
-MONA
- P2Y12 inhibitors
- Platelet glycoprotein IIb/IIIa inhibitors
- Unfractionated heparin
- βblockers
What meds are used for thrombolytic therapy?
- tPA
- Streptokinase
- Reteplase
- Tenecteplase
What is the time frame to give tPA?
- Earlier the better
- 30-60min of hospital arrival, within 12 hours of symptom onset
What is the goal of thrombolytic therapy?
Restore normal anterograde blood flow in occluded coronary artery
What is the urgency of surgery if life or limb would be threatened if surgery did not proceed within 6 hours or less?
Emergency
What is the urgency of surgery is life or limb would be threatened if surgery did not proceed within 6 to 24 hours?
Urgent
What is the urgency of surgery if delays exceeding 1 to 6 weeks would adversely affect patient outcomes?
Time-sensitive
Pre-op Cardiac Risk Assessment Algorithm
ACC/AHA algorithm recommends that a patient with a functional capacity of ____ METs should proceed directly to surgery
4 or more
Preoperative _____ ______ is most suitable for patients with stress test results suggesting significant myocardium at risk
coronary angiography
What are the goals for anesthesia in patients with ischemic heart disease?
- Prevent myocardial ischemia
- Monitor for ischemia
- Treat ischemia
What are anesthetic considerations for prevention of ischemic heart disease?
- Persistent tachycardia
- Systolic HTN
- SNS stimulation
- Arterial hypoxemia
- Hypotension
**Maintain BP and HR within normal awake baseline
What things are a result of decreased oxygen delivery?
- Decreased coronary blood flow
- Tachycardia
- Hypotension
- Hypocapnia
- Coronary artery vasospasm
- Decreased oxygen content
- Anemia
- Arterial hypoxemia
- Shift of the oxyhemoglobin dissociation curve to the left
In patients with Ischemic HD, hyperventilation must be avoided because _____ may cause coronary artery vasoconstriction
Hypocapnia
What things increase oxygen requirements in patients with ischemic HD?
- SNS stimulation
- Tachycardia
- Hypertension
- Increased myocardial contractility
- Increased afterload
- Increased preload
Why might opioids be preferred at the principal anesthetic?
Patients with severely impaired LV function may not tolerate anesthesia induced myocardial depression
What meds would you give if HTN exists longer than 15 seconds while intubating and why?
Laryngotracheal lidocaine, IV lidocaine, esmolol, fentanyl, remifentanil and precedex
- they can all blunt the increased HR caused by intubation
Anesthetic considerations for ischemic heart disease:
- Succinylcholine, vec, roc, cis
- DL 15 seconds or less
- Volatile anesthetics
- Nitrous oxide
- Opioids
- Neuraxial anesthesia
Why would volatile anesthetics be beneficial in patients with ischemic hd?
they decrease myocardial oxygen requirements and may precondition the myocardium to tolerate ischemic events
Why could volatile anesthetics be detrimental in patients with ischemic hd?
they lead to a decrease in blood pressure and an associated reduction in coronary perfusion
What are the risks of using epidural or spinal anesthesia in patients with ischemic hd?
They decrease blood pressure - prompt treatment of hypotension that exceeds 20% of the preblock blood pressure is necessary
What is the drug of choice for tachycardia in patients with ischemic hd?
Esmolol
What is the drug of choice for bradycardia in patients with ischemic hd?
Glycopyrrolate (over atropine)
Treatment for hypotension in patients with ischemic hd:
- Fluid bolus
- Sympathomimetic drugs: ephedrine preferred over epi because it won’t make you tachycardic
Monitoring for Ischemic HD:
Vessel occlusion:
