Acute Coronary Syndrome Part 1 Flashcards
What is the difference between NSTEMI and STEMI
- stemi: there is completely occlusion of the artery
- nstemi: lumen is occluded only partly- there is still some coronary blood flow
What is the difference between the thrombus is the NSTEMI and STEMI?
stemi: full blown coagulation pathway and see a lot of fibrin here
nstemi: mainly platelets in the thrombus
______ is an enzyme that is released when there is myocardial necrosis
troponin
Where is the worst place to have an occlusion in the heart? Why is this?
- left main coronary artery
- this is the worst place because there is a large amount of downstream blockage
Describe a STEMI
- most severe type of ischema in the pathophysiologic continuum of the acute coronary artery syndrome
- caused by complete occlusion of a coronary artery by clot (rupture of atherosclerotic plaque)
- STEMI comprises approx. 25-40% of MI presentations
- in hospital mortality rates are 4.6% vs 2.2% for patients with STEMI and NTEMI, respectively
What are the classic presenting symptoms of coronary artery syndrome?
- central chest paon (typically radiating to shoulder, down the left arm, to the back or the jaw); may be accompanied by SOB, n/v, diaphoresis
What are the symptoms associated with silent type MIs?
- no chest pain or discomfort
- more often here they describe SOB, indigestion or diaphoresis, other sx like fatigue, faintness, dizziness, light-headedness, anxiety and palpitation
What demographic groups are less likely to have classic symptom presentation?
- elderly, diabetic patients and women
What are the major SIGNS of acute coronary syndrome?
- syncope
- bradycardia (inferior infarction), tachycardia (increased sympathetic activity, decreased cardiac output), other arrhythmias
- elevated or low BP
- diffuse rales, wheezing or respiratory distress usually indicate pulmonary oedema and CHF
- jugular venous distention indicates right atrial hypertension, usually from RV infarction or elevated LV filling pressure
What are the 2 enzymes that are released into the circulation when cardiac cells are damaged?
- creatinine kinase
- troponins
What can be expected from CK (creatinine kinase) levels after an MI?
- these should be detectable in the serum within 3-5 hours after an MI, peaks in 12-24 hours, stays elevated for 2-3 days
- this can be elevated in other non-ACS conditions (e.g. pericarditis, myocarditis, rhabdomyolysis, renal failure)
What is the preferred biomarker for detecting an acute coronary syndrome?
- troponins
What can be expected from troponin levels after a coronary artery syndrome?
- troponin T appears in serum within 4-12 hours after an MI onset peaks in 12-48 hours, and stays elevated for 7-10 days
When should biomarker essays be done after an MI?
- should be done stat on presentation, then should be redone every 4-6 hours for the first 12-24 hours, then periodically
What needs to be seen on lab tests for the diagnosis of a STEMI or an NSTEMI?
- at least 2 elevated CK-MB or 1 TnT exceeding the upper reference range is needed (usually 2 successive blood samples)
What are the advantages of an ECG?
- get results immediately
- can be very indicative of if patient is having a STEMI or something else
- will give the location of the infarct
What signs on an ECG can be indicative of a STEMI?
ST elevation
What signs on an ECG can be indicative of a NSTEMI?
ST depression
T wave inversion
What is the main initial management of acute coronary syndrome? (4 things)
- oxygen at 4 L/min by nasal prong to maintain O2 saturation >90% (preferably 95%)
- ASA 162-325 mg po chew/shallow (if not already given by EMS)
- Nitroglycerin SL or IV
- Morphine 2-5 mg IV q5-30 min prn (could use other analgesics such as fentanyl) -if pain not relieved by nitro
can be described as MONA
What is the main priority in STEMI?
- priority is to quickly reestablish blood flow to the occluded artery as quickly as possible (need to enhance perfusion)
What is the main priority in STEMI?
- priority is to quickly reestablish blood flow to the occluded artery as quickly as possible (need to enhance perfusion)
What are the 2 types of reperfusion strategies in STEMI?
- primary percutaneous coronary intervention (PCI)
2. Fibronolytics (in STEMI, the thrombus is heavily laced with fibrin)
What are the goals of therapy in reperfusion?
- decrease mortality and complications
- reduce or contain infarct size
- salvage functioning myocardium and prevent remodelling
- re-establish potency of the infarct-related artery (clear occlusion, reestablish flow of coronary blood)
What is the recommended method of reperfusion?
- primary PCI (when it can be performed in a timely fashion)
- ideal medical contact to device time of <90 minutes should be targeted for primary PCI
- if fibrinolytic therapy is chosen as the reperfusion strategy, it should be administered within 30 minutes of hospital arrival
Describe the process of a primary PCI?
- diagnostic catheter is placed and advanced through the femoral artery to the aorta and the coronary arteries
- contrast dye is injected once the catheter is in place. X-rays are taken to locate the exact location of coronary occlusion
- a balloon catheter (with or without a stent mounted) is advanced to the blockage site. Once at the site, the balloon is inflated for a few seconds to open the blocked coronary
- the stents are left in place to keep the coronary vessel open
How long should someone be on anti-platelet therapy after a PCI?
- should be on anti-platelet therapy for a minimum of 1 year after a PCI
What is the TIMI grade flow? What TIMI blood flow do we want to achieve?
- adopted scoring system from 0-3 referring to the level of coronary blood flow assessed during a PCI
- we want to achieve TIMI 3 blood flow for complete perfusion
What is the TIMI grade flow? What TIMI blood flow do we want to achieve?
- adopted scoring system from 0-3 referring to the level of coronary blood flow assessed during a PCI
- we want to achieve TIMI 3 blood flow for complete perfusion
Angioplasty without _____ is rarely used in the setting of the ACS now
stenting
—- PCI procedures almost always involve a bare metal send or a drug eluting stent
What is a drug eluting stent and why is it most commonly used?
- a stent that has anti proliferative drugs coating on the stent scaffold, which is released slowly over time to prevent restenosis
- — body will naturally want to endotheliaze around the stent- this is why drug coating is important
Patients who ave received a DES will require dual-antiplatelet therapy for a minimum of _____
1 year
What is the timeframe that fibrinolytics need to be given for the greatest mortality benefit
needs to be given within 0-2 hours (target time of 30 minutes)
Why are fibrinolytics not administered to NATEMI/UA patients?
- this goes back to the pathology of clotting- in STEMI there is a big thrombus made up of heavy fibrin, which is not found in NSTEMI/UA
- fibrinolytic add risk of bleeding and is not worth this risk in anything but STEMI
What fibrinolytic should be given due to its high specificity?
- tenecteplase when possible should be given as a single IV bolus for 5 seconds
What are the main benefits of giving tenecteplase over over fibrinolytics?
- there are 20% fewer major non-cerebral bleeds
- little effect on blood pressure
- most fibrin-specfic agent
What are the absolute contraindications to fibrolytics?
- any prior ICH
- known structural cerebral vascular lesion
- known malignant intracranial neoplasm
- ischemic stroke within 3 months
- suspected aortic dissection
- active bleeding
- significant closed head or facial trauma within 3 months
- severe uncontrolled hypertension
- for streptokinase, prior treatment within the previous 6 months
______ are the cornerstone therapy in STEMI management
antithrombotics (anti platelets and anticoagulants)
When is the use of heparin appropriate for use in ACS with someone ?
- usually initiated on presentation and discontinued after PCI
What should be given to STEMI patients undergoing primary PCI?
- ASA 162-325 mg po should be given before PCI PLUS
a loading dose of a P2Y12 receptor inhibitor as early as possible before PCI
— clopridogrel 600 mg, prasugrel 60 mg or ticagrelor 180 mg —- ticagrelor is the 1st recommended
How long should a P2Y12 inhibitor be used after ACS?
- should be used for the minimum of 1 year (can be used even more though)
What antithrombotics are appropriate to use in STEMI patients receiving fibrinolytics?
- ASA 162-325 mg po should be given on presentation PLUS
- clopridogrel loading dose along with clopridogrel 75 mg po daily for 14 days
What is the appropriate use of heparin in STEMI patients receiving fibrinolytics?
- LMWH or UFH should be initiated at the time of fibrinolysis and continued for a minimum of 48 hours and up to 8 days (or until revascularization)
What is enoxaprin?
- most commonly used LMWH
What heparin needs to be monitored more regularly?
LMWH needs to be monitored more often
- UFH should be used in those that we are not sure of their dose and in renal impairment and the obese
Should enoxaprin always be given as an IV bolus?
- NO
- it should only be given as a bolus dose in STEMI patients under the age of 75
When is the use of heparin indicated in patients?
- should be used in patients >149 kg (little evidence to support LMWH in these patients)
- used for those with renal impairment, CrCl <30 mL/min
Clinical trials suggest better efficacy profile with what combination of drugs when compared to ASA+clopridogrel in patients with STEMI undergoing primary PCI
ASA and prasugrel
ASA and ticagrelor
Prasugrel should not be used in what patients?
in those with a history of stroke or TIA due to higher rates of major bleeding in these populations
Triple therapy of _______ may be indicated in STEMI patients with low ejection fraction or if the patient has a concurrent AF
DAPT and warfarin
What needs to be monitored in a patient after repercussion therapy is done?
Need to monitor for EFFICACY
- signs and sx of ongoing chest pain, ECG changes, serial monitoring of biomarkers
- stent thrombosis
- complications: arrhythmias, HF, pericarditis
Need to monitor for SAFETY
- major and minor bleeding complications
- clinical signs of bleeding include bloody stools, melon, hematuria, hematemesis, bruising, and oozing from arterial or venous puncture sites
What are some of the main complications associated with a STEMI?
- Heart failure
- Cardiogenic shock
- Arrhythmias
- Pericarditis
What causes heart failure after an MI?
- LV myocardium may be ischemic, stunned, hibernating or irrevocably injured after MI
What is used to assess LV ejection fraction?
echocardiography
- intervention is required in those with a LVEF <40%
What causes cariogenic shock after an MI?
- decreased cardiac output and evidence of tissue hypoxia in presence of adequate intravascular volume
- this is often due to an extensive LV infarction
- can also be due to systolic, diastolic and valvular dysfunction
- incidence ~10% of hospitalized STEMI patients
What causes an arrhythmia to arise post MI?
- due to ischemia and severe HF
- there will be some rhythm changes as you are re-gaining oxygen to myocardium
- ventricular arrhythmias are more probable in the peri-infarction period
What is the role that beta blockers will play post MI?
- increase myocardial salvage in the infarct area
- prevent extension of infarction by reducing oxygen consumption/demand
- decrease cardiovascular mortality, recurrent nonfatal MI and all-cause mortality
When are beta blockers indicated after an MI?
- should be initiated within 24 hours post MI
What is the goal HR when giving a beta blocker post MI?
55-60 bpm
What are the contraindications to beta blockers?
- hypotension (systolic BP <90)
- bradycardia (HR <50 bp)
- acute HF
- cardiogenic shock
- asthma
- 2nd or 3rd degree AV block
What is the role of a ACEI after an event?
- minimize ventricular remodeling
- reduce oxygen demand and myocardial wall stress by reducing after load or preload
- reduction in cardiovascular mortality and morbidity
The benefit of and ACEI is greatest in what population?
- anterior infarction, HF (LVEF <40%), patients with diabetes or CKD
- should be initiated win 24 hours of an MI once BP is stabilized
What groups are ACEIs CI’ed in?
- in those with renal impairment and hyperkalemia
What is important to monitor for with an ACEI?
- SCr, electrolytes, watch for hyperkalemia (K>5.5) especial with concurrent spironolactone
What is evolovumab?
- its a monoclonal antibody (biologic) that inhibitrs PCSK9 - lowers the LDL
When would an aldosterone antagonist like spironolactone be used?
- may be indicated if the patient has severe LV dysfunction (EF <40%)
When would aldosterone antagonists be contraindicated in patients?
caution in patients with CrCl <30 ml/min and K 5 mEq
- check the potassium at baseline and within 1 week of initiation
What are some of the non-pharamcological things that can be done to help patients manage after ACS?
- cardiac rehab program
- weight management (BMI 18.5-25, waist circumference, goal of 5-10% weight reduction)
- physical exercise (goal of 30-60 minutes of moderate activity)
- implantable cardioverter/defibrillator assessment for patients with ongoing LV dysfunction
- depression screening/stress management
