JH IM Board Review - Coronary Artery Disease II Flashcards
ACS includes (3):
- UA.
- NSTEMI.
- STEMI.
All 3 syndromes occur when …
A VULNERABLE PLAQUE RUPTURES.
==> PLT activation and aggregation ==> Intracoronary thrombus.
Definition of UA:
- Angina at rest (>20min).
- New-onset exertional angina of at least class III in severity (ie w/ mild exertion).
- Preexisting angina that has increased in frequency or duration or that is now brought on w/ less exertion than before.
Definition of NSTEMI:
Clinically similar to UA, but distinguished by evidence of myocardial necrosis (ie elevation in serum cardiac enzymes).
ECG does not show ST elevation.
Definition of STEMI:
Elevated cardiac enzymes and ECG criteria that include >1mm ST segment elevation in two or more contiguous limb leads.
Or >2mm ST segment elevation in 2 or more contiguous PRECORDIAL leads.
Of note, a new or presumed new LBBB is …
NO LONGER considered a STEMI equivalent. (2013 ACC/AHA)
==> Must employ other ECG criteria to diagnose MI in these cases.
NSTEMI vs STEMI - ECG:
NSTEMI ==> ST depressions, T inversions, nonspecific ST-T changes.
STEMI ==> ST elevation.
NSTEMI vs STEMI - Vessel at time of catheterization:
NSTEMI ==> 30-40% occluded.
STEMI ==> >80%.
NSTEMI vs STEMI - Type of clot?
NSTEMI ==> Rich in PLTs (white).
STEMI ==> Rich in fibrin (red).
NSTEMI vs STEMI - Extent of disease?
NSTEMI ==> More likely collateral formation and multivessel disease.
STEMI ==> More commonly single vessel.
NSTEMI vs STEMI - Tx:
NSTEMI ==> Thrombolysis NOT recommended — GP IIb/IIIa inhibitors can be useful.
STEMI ==> Thrombolysis beneficial — GP IIb/IIIa inhibitors usually not indicated (unless PCI performed).
NSTEMI vs STEMI - Hospital mortality?
NSTEMI ==> Lower.
STEMI ==> Higher.
NSTEMI vs STEMI - Reinfarction rate?
NSTEMI ==> Higher after d/c.
STEMI ==> Lower after d/c.
NSTEMI vs STEMI - Long-term prognosis?
NSTEMI ==> Higher 1y mortality rate after d/c.
STEMI ==> Lower 1y mortality rate after d/c.
Of note, …-…% of ACSs are clinically silent.
20-30%.
TIMI (thrombolysis in MI) risk score for UA/NSTEMI - RFs:
7
- > 65y.
- 3 or more coronary artery RFs.
- Prior coronary stenosis >50%.
- > 2 anginal events in past 24h.
- Aspirin use in past 7 days.
- ST-segment changes.
- Positive cardiac markers.
Risk of adverse cardiac event by TIMI score:
0-1 ==> 4.7% (Low risk).
2 ==> 8.3% (Low risk).
3 ==> 13.2% (Intermediate risk).
4 ==> 19.9% (Intermediate risk).
5 ==> 26.2% (High risk).
6-7 ==> 41% (High risk).
Calculate GRACE (Global Registry of Acute Coronary Events) 2.0 risk score.
Incorporates (7):
- Age.
- HR.
- SBP.
- Killip class.
- Presence of cardiac arrest.
- ST-segment change.
- Troponins.
The GRACE 2.0 score estimates …
6mo mortality.
Always consider other diagnoses that can mimic ACS (3):
- AD.
- Acute pericarditis.
- PE.
AD - ECG can reveal ST elevations if the …
Dissection involves one or more of the coronary arteries.
typically affect the RCA first
Management of UA/NSTEMI - Medical therapy consists of (6):
- Antiplatelet therapy.
- Antithrombotic therapy.
- Beta blockers.
- Nitrates.
- CCBs.
- Statins.
UA/NSTEMI - Antiplatelet therapy consists of …
- Aspirin.
- Thienopyridines.
- GpIIb/IIIa inhibitors.
UA/NSTEMI - Aspirin leads to more than …% relative reduction in risk of MI and death.
50%.
Should be continued INDEFINITELY.
UA/NSTEMI - Thienopyridines - Clopidogrel:
Reduces adverse cardiac events in pts with UA/NSTEMI when given in addition to aspirin.
==> Continue for at least 12mo if PCI with DES.
==> 1 month if PCI with BMS.
==> 9 mo if NO PCI.
UA/NSTEMI - Prasugrel should be avoided in pts who may be potential candidates for …
CABG.
UA/NSTEMI - Role of GpIIb/IIIa:
Clear benefit demonstrated in both UA and NSTEMI.
==> The greatest benefit is seen in pts who have positive troponins and are treated with PCI.
Abciximab has clear benefit in …
UA/NSTEMI undergoing PCI.
NO BENEFIT in pts with UA/NSTEMI who do NOT require PCI.
Antithrombotic therapy is a/w …
Lower rates of MI and death in pts with ACS.
Enoxaparin compared to UFH in UA/NSTEMI?
Superior to UFH in reducing death, MI, and recurrent ischemic events in pts who are treated CONSERVATIVELY.
==> No difference in pts treated invasively, and also a/w higher rate of bleeding.
Fondaparinux can be used …
Both with conservative strategy and as an invasive strategy in pts with UA/NSTEMI.
==> Preferable to UFH or enoxaparin in pts with increased risk of bleeding.
Direct thrombin inhibitor - Bivalirudin is an option only in pts in whom …
An early invasive approach is planned.
==> If high risk of bleeding exists, then bivalirudin monotherapy can be considered instead of heparin/GpIIb/IIIa inhibition combination.
Beta blockers in UA?
Reduce ischemia + shown to reduce subsequent infarction.
Beta blockers in NSTEMI?
- Reduce ischemia + infarct size.
- Help prevent reinfarction.
- Decr mortality.
Administer beta blockers orally if there is no evidence of …
Acute heart failure.
Do not give diltiazem, verapamil, or nifedipine in pt with LVEF
40%.
Statins in UA/NSTEMI?
They have been shown to have antiplatelet and antioxidant properties as well.
Thrombolytics in UA/NSTEMI?
NOT indicated.
Cardiac catheterization in UA/NSTEMI - Emergent indications:
3
- Persistent ischemia despite medical tx.
- Hemodynamic instability.
- V-tach, v-fib, SCD.
Catheterization in UA/NSTEMI - Indications in pts stabilized w/ medication tx:
- Stress test — positive high-risk results.
- ECG: ST depression suggesting ischemia in a large territory.
- ST depression on ECG + elevated enzymes.
- DM.
- CKD.
- Low EF.
- TIMI risk score: High or intermediate risk.
- GRACE score >140.
Thrombolytic tx in STEMI is successful in …%
60%.
Thrombolytics for STEMI are most effective when given in the first …, but can be given up to … after onset of pain.
6h
12h
Between …-…, only consider thrombolytics if there is no available PCI, and the STEMI pt has hemodynamic compromise or a large myocardial area at risk.
12-24h
Thrombolytic tx in STEMI — Indication?
Duration of sx <12h.
Thrombolytic tx in STEMI — Absolute contra:
7
- Hx of ICH.
- Known cerebral vascular lesion (eg AVM).
- Known malignant intracranial neoplasm.
- Ischemic stroke within 3mo.
- Suspected AD.
- Active bleeding or bleeding diathesis.
- Closed-head or facial trauma within 3mo.
Thrombolytic tx in STEMI — Relative contra:
8
- SBP >180 or DBP >110 AT PRESENTATION.
- Hx of ischemic stroke >3mo.
- Prolonged CPR (>10min).
- Major surgery within <3wks.
- Recent internal bleeding (within 2-4wks).
- Pregnancy.
- Active PUD.
- For strepto/anistreplase ==> Prior exposure >5 days ago or prior allergic reaction.
Thrombolytics a/w hemorrhagic stroke — Which groups are more prone to?
(5)
- Elderly.
- Women.
- HTN.
- DM.
- Pts w/ previous stroke or treated w/ warfarin.
PCI — Major advantages over thrombolytics:
- Higher reperfusion rates (>90% success rate).
- Decreased incidence of stroke.
- More effective than thrombolytics in pts w/ acute decompensated HF, cardiogenic shock, and prior bypass surgery.
PCI — Major disadvantages over thrombolytics:
Not available in all hospitals.
Terminology — Primary PCI:
Pt w/ STEMI is taken directly to the catheterization lab for PCI instead of receiving thrombolytics.
Terminology — Rescue PCI:
Urgent PCI after failure to reperfuse w/ thrombolytics.
Terminology — Pharmacoinvasive PCI:
PCI after reperfusion w/ thrombolytics.
Approx. …-…% of pts receiving thrombolytics fail to reperfuse and have high mortality rates.
They have better outcomes if they then undergo rescue PCI.
20-30%.
Of note, … suggests successful reperfusion after thrombolytic administration.
Accelerated idioventricular rhythm.
Medications NOT recommended for STEMI tx?
- Empirical antiarrhythmics ==> Proph antiarrhythmic use can actually increase mortality in the peri-MI setting.
- GpIIb/IIIa inhibitors ==> Only useful if undergoing PCI. Not useful in conjunction w/ thrombolytics.
12 complications of MI:
- Bradyarrhythmias.
- Mobitz I.
- Mobitz II.
- 3o AV block.
- BBB.
- Premature ventricular contractions.
- V-tach or V-fib.
- Papillary muscle rupture.
- Ventricular septal rupture.
- Ventricular free wall rupture.
- RV infarct.
- Pericarditis.
Bradyarrhythmias are usually seen in the first …-… for all types.
24-48h.
Mobitz I is usually seen w/ …
IMI ==> Ischemia or increased vagal tone.
Conduction block usually in AV node.
Mobitz I may cause …
Asx hypotension.
Mobitz I responds to …
Atropine and usually resolves in 2-3 days.
Mobitz II is caused usually by …
Anterior MI.
Block typically INFRANODAL.
Mobitz II may cause …
Asx hypotension.
Mobitz II needs …
Temporary pacer b/c high risk for progression to complete block.
==> Many require permanent pacer.
3o degree block is caused by either …
Anterior MI or IMI.
3o degree AV block is treated w/ …
Permanent pacer usually required w/ AMI.
Often resolves spontaneously w/ IMI.
BBB is usually caused by …
Anterior MI.
BBB is usually seen during the first …-… .
24-48h.
BBB - Tx?
Temporary pacer indicated for:
- Alternating LBBB and RBBB.
- RBBB w/ alternating Left Anterior Fascicular Block (LAFB) + LPFB.
- LBBB or RBBB w/ 1o AV block.
***BBB a/w higher mortality.
Premature ventricular contractions are usually caused by …
Any MI.
Premature ventricular contractions are usually caused during the first …-… .
24-72h.
Usually asx.
Tx for premature ventricular contractions:
- Usually not required.
- Avoid lidocaine (can incr. mortality).
- Can use beta blockers.
V-tachy/V-fib are caused by …
MI of any territoery, but commonly AMI.
V-tachy/V-fib are usually seen when?
VT in first 24h ==> Usually transient and benign.
Late VT ==> Consider recurrent ischemia.
Most VF occurs in first 48h.
Beta blockers … the incidence of lethal VFs.
Decrease.
Papillary muscle rupture - Tx:
Intra-aortic balloon pump (IABP) ==> To help stabilize.
Urgent surgery is required.
Ventricular septal rupture - Usually caused by which type of MI?
Both AMI and IMI.
Ventricular septal rupture may occur …-… after MI.
1-20 days.
Ventricular free wall rupture may occur …-… after STEMI.
2-14 days.
Which group is at highest risk for ventricular free wall rupture?
Elderly women.
Implantable defibrillators — Improve survival in pts w/ …
Ischemic cardiomyopathy and low EF (even in the absence of V-arrhythmias).
Implantable defibrillators — Measure EF at least … after MI in pts who are being treated w/ goal-directed medical HF tx.
ICD indicated if EF
40 days.
30%
35%