Unstable Angina And NSTEMI Flashcards
Define unstable angina/angina pectoris
Chronic discomfort with at least one:
1) occurs at rest or with minimal exertion lasting >10mins
2) severe and of new onset within the last 4-6 weeks
And/or
3) occurs with crescendo pattern (more severe, prolonged, frequent)
Define stable angina
Chest or arm discomfort, reproducibly associated with physical exertion or stress, relieved in 5-10 mins by rest or sublinguala
Define NSTEMI
UA + evidence of myocardial necrosis plus elevated biomarkers
4 pathologic processes in ua/nstemi
- plaque rupture or erosion with a superimposed thrombus
- dynamic obstruction like in Prinzmetal’s angina
- progressive mechanical obstruction
- unstable angina secondary to myocardial oxygen demand and/or decreased supply, eg tachycardia or anemia
How many ua/nstemi pts present with LMCA stenosis? With 1 vessel dse? With 2 vessel dse?
5%
40%
30%
While 15 percent have three vessel dse
Compare thrombi of stemi vs nstemi
Stemi - red, fibrin and cell rich
Nstemi, ua - white/platelet rich
PE of ua/nstemi
Can be u/r If large area of ischemia: Diaphoresis Pale, cool skin Sinus tachy 3rd/4th heart sound Hypotension
ECG findings of ua/nstemi
St segment depression
Transient st elevation
T-wave inversion
T wave changes are sensitive for ischemia but less specific unless >=0.3mV
Risk of death in 1 mo. In ua/nstemi
Risk of recurrent infarction
Risk of recurrent ACS
1-10%
3-5%
5-15%
Broadly speaking; anti-ischemic treatment of ua/nstemi
Bed rest, nitrates, beta blockers (use with caution in acute HF[risk of shock] an you can consider CCBs diltiazem or verapamil if contraindicated)
But also start ACEIs and statins eg atorvastatin 80mg
How you give nitrates in ua/nstemi
SL or buccal spray if in pain
Switch tO IV if still in pain after 3doses 5 mins apart:
Nitroglycerin 5-10ug/min in nonabsorbable tubing, titrate in increments of 10ug/min every 3-5 mins until relieved or sbp<100
Can shift to oral nitrates if pain free for past 12-24h
Only absolute contraindications to nitrates
Hypotension
Use of suldenafil or similar in 24-48h
Indication of morphine sulfate in ua/nstemi
Dosing and administration
Pts with ssx not relieved after 3 serial NGL tablets or whose ssx recur with adequate anti-ischemc therapy
Give 2-5mg IV, repeated evey 5-30mins as needed
Dose of aspirin recommended in ua/nstemi
325mg/d as initial dose
75-162 for long term
Clopidogrel: class and MOA
Thienopyridine
Inactive prodrug whose active metabolite blocks the platelet P2Y12 component of ADP receptor
Findings of the CURE Trial re: clopidogrel: ups and downs
In combination with aspirin: 20% less risk of death, MI, stroke
But inc risk of major bleed by 1%
Why do some (up to 1/3) of patients have a low response to clopidogrel?
What do you do about it?
Genetic variant of the cytochrome p450 system: variant of 2C19 gene –> reduced conversion of clopidogrel to active metabolite
Consider prasugrel
When do you avoid beta blockers in ua/nstemi?
PR interval>0.24s Second or third degree heart block Heart rate <90 Shock LV failure Severe reactive airways disease
When to avoid morphine in ua/nstemi
Hypotenstion, resp depression, confusion, obtundation
When not to give CCBs in ua/nstemi
Evidence of LV dysfunction (for diltiazem or verapamil)
Pulmonary edema
Discuss positive and negative aspects of prasugrel vs clopidogrel
Advantage: dec CV death, MI, stroke
Decreased risk of stent thrombosis
Disadvantage: inc risk major bleeding
Contraindications to prasugrel use
Prior stroke
TIA
Reversible ADP inhibitor
Ticagrelor
Dec mortality and cv death without known inc in major bleed
Mainstay of anticoagulant tx
Dosing and administration
Unfractionated hep
Bolus 60-70 u/kg, mac 500 u, IV
Infusion 12-15 U/kg/hr
Titrate to ptt 50-70s
Advantage of LMWH/enoxaparin vs ufh
Administration
Reduced cardiac events
1mg/kg SC q12, can have 30mg IV loading dose
Renal adjustment of lmwh
If crea clearance is less than 30cc/min adjust to half or 1mg/kg OD
Mechanism of action of fondaparinux
Indirect factor Xa inhibitor
Equivalent early efficacy with enox but lower bleeding
Fondaparinux administratiob
2.5mg SC OD
What is early invasive management in ua/nstemi
Coroangio in 48 hours
Then PCI or CABG
When do you give early invasive management? (Class I recommendations) (9)
Recurrent angina at rest or low level activity despite tx
Elevated TnT or TnI
New ST depression
Recurrent angina or ischemia with chf sx, rales, MR
Positive stress test
Ef less than 40%
Decreased BP, sustained VT, PCI less than 6mos/prior CABG
