acute coronary syndrom

• Define myocardial infarction?


  -Permanent occlusion of a coronary blood vessel usually due to a plaque rupture & thrombus formation

  -Occlusion rapidly results in rapid necrosis of myocardial tissue
• When does necrosis begin as a consequence of occlusion?

  -Starts within 30mins of occlusion & if not removed permanent necrosis will occur after 6-12 hours
• What is infarction described in terms of?

  -Presence or absence of significant ST segment elevation

  -Describes a newly identified group of pats. w/ an adverse prognosis presenting w/ elevated serum cardiac troponin levels w/out elevation of total serum creatinine kinase
• What is Q-wave myocardial infarction now referred to as?

  ST segment elevation myocardial infarction or ST segment elevated acute coronary syndrome (STEMI/STEACS)
• What is non-Q-wave myocardial infarction now referred to as?

  Non ST segment elevation myocardial infarction or non ST segment elevated acute coronary syndrome (NonSTEMI/NSTEMI/NSTEACS)
• What is the diagnosis of unstable angina, minor myocardial damage & non-STEMI considered as?

  -A continuum
• What is prognosis & treatment closely related to for unstable angina, minor myocardial damage & non-STEMI?

  -Serum troponin levels
• What are cardiac troponins?

  -Sensitive & specific markers of myocardial injury

  -
• What confirms myocardial damage?

  -Presence of cardiac troponin I or T (TnI to

  -Presence of cardiac troponin correlates w/ subsequent risk of cardiac death
• What is better at predicting adverse events CK-MB or troponins?

  Troponins superior
• When should cardiac troponins be measured after onset of chest pain to exclude myocardial injury?

  -6-8 hours after onset
• how can cardiac troponins be used to tailor therapy?

  -As they predict response to treatment w/:

  -LMWH in acute coronary syndromes w/out ST

  elevation

  -Tirofiban in acute coronary syndromes w/out ST

  elevation

  -Adjunctive use of abciximab w/ percutaneous

  coronary intervention
• Diagnosis of acute coronary symptoms?

  -Treatment guidelines utilise initial 'working diagnosis' based on risk stratification to guide early treatment Strat.

  -Final diagnosis takes time, as time is needed for the markers of myocardial necrosis to become evident
• What is considered as a medical emergency for acute chest pain & what should the pat. do?

  -Chest pain at rest or for long period of time (>10 mins, not relieved by SL nitrates)

  -Recurrent chest discomfort

  -Discomfort associated w/ syncope or acute heart failure

  
  

  -Pat. should go to hospital ASAP
• The presentations of ACS & what pat. should do if experiencing them?

  -Back, neck, arm or epigastric pain

  -Chest tightness

  -Dyspnoea

  -Diaphoresis (excessive sweating)

  -N & V

  -Sharp pain more common in women, diabetics & elderly

  
  

  -Seek medical help 999

  -Access to defibrillator to avoid early death from reversible arrhythmias
• Actions in transit for suspected ACS?

  -Aspirin 300mg (chew & swallow) unless has been already given or c/i

  -o2

  -GTN & IV morphine if req.

  
  

  If avail. in ambulance:

  -12 lead ECG

  -Warn hospital of impending arrival
• Action on arrival to hospital?

  Initial investigation?

  -Immediate ECG

  -Dr to see pat. w/in 10 mins of arrival

  -Commence o2

  -pain relief

  -Blood tests for biomarkers

  -Aspirin 300mg unless already given
• Early management of STEMI?

  -Offer 300mg loading dose of aspirin ASAP & cont. aspirin indefinitely unless c/i-Immediately assess for reperfusion therapy if eligible, offer ASAP-Angiography w/ follow-on primary PCI-offer if presenting in 12 hours of symptoms & PCI can be delivered in 120 mins-Consider if presenting > 12 hrs after symptoms & continuing myocardial ischaemia or cariogenic shock

  -Fibrinolysis-Offer if presenting in 12 hrs of symptoms & PCI not possible in 120 mins-Give an antithrombin at same time
• Aims of treatment for management of STEMI?

  -Relieve pain

  -Achieve coronary reperfusion & minimise infarction size

  -Prevent & treat heart failure, shock or other complications

  -Prevent & treat cardiac arrest

  -Unnecessary anxiety
• What is STEMI presentation defined as?

  -Clinical symptoms consistent w/ an ACS w/ ECG features including:

  -Persistent ST-segment elevation of >1mm in 2 contiguous limb leads

  -ST-segment elevation of >2mm in 2 contiguous chest leads or

  -New left bundle branch block
• What is reperfusion therapy?


  medications or procedures used to open a blocked coronary artery
• What are the 2 options of reperfusion therapy?

  -Fibrinolysis

  -or PCI

  (Sometimes CABG may be more apt)
• What is fibrinolysis & give 2 examples?

  Use of clot dissolving drugs (Alteplase, Tenecteplace)
• What is PCI?


  Percutaneous coronary intervention (angioplasty & stenting)
• Pats. w/ STEMI who present within 12 hours of onset of ischaemic symptoms should be given?

  Reperfusion therapy ASAP
• What is generally preferred PCI or Fibrinolysis & why?

  -PCI

  -Better short & long term outcomes (reduced deaths, MIs & stroke if pat. presents w/ STEMI w/in 12hrs of symptom onset
• What does choice of reperfusion therapy depend on?

  -Time delay to PCI

  -Time from presentation to balloon inflation if > 120 mins use fibrinolysis

  -Time from onset of symptoms until medical contact

  -Time to hospital fibrinolysis

  -C/I to fibrinolytic therapy

  -Location & size of infarction

  -Presence of cariogenic shock
• Absolute C/I to fibrinolysis (thrombolysis)

  -Active bleeding (excl. menses)

  -Significant closed head or facial trauma w/in 3 months

  -Suspected aortic dissection

  -Prior intracranial haemorrhage

  -Ischaemic stroke w/in 3 months

  -
• Relative C/I to fibrinolysis (thrombolysis)

  -Concurrent anticoagulants

  -Non-compressible vascular punctures

  -Recent major surgery < 3 weeks

  -Traumatic or prolonged CPR >10mins

  -Recent internal bleeding > 1 month

  -Active peptic ulcer

  -History of chronic, severe, poorly controlled hypertension or severe uncontrolled hypertension on presentation

  -Ischaemic stroke > 3 month, dementia or intracranial abnormality

  -Pregnancy
• Fibrinolysis/thrombolytic therapy options?


  -Streptokinase, Alteplase, tenecteplase
• Info on Streptokinase?


  -Cheap

  -Shouldnt be given to pats. w/ previous exposure >5 days
• Info on alteplase & tenecteplase?

  -Fibrin specific agents

  -Better reduction in mortality compared to streptokinase if given w/in 6 hours of symptom onset
• Clinical significance of alteplase?

  -Superior to streptokinase in pats under 75 yrs & if used w/in 4 hrs of onset of chest pain

  -Given as bolus followed by infusion
• Clinical significance of tenecteplase?

  -Convenient (given as boluses) but more expensive

  -Fibrinolytic of choice

  -Tenecteplase has lower rate of bleeding then alteplase
• Side effects of thrombolytics?

  -Bleeding-major haemorrhage (intracerebral & GI)

  -Allergic reactions, common w/ streptokinase
• what is the management of complications for the treatment of STEMI?

  -Complications are managed as they occur

  -Common problems incl:

  -Persistent or recurrent pain

  -Left ventricular failure

  -Cardiogenic shock

  -Arrhythmias
• Treatment/ early management of NSTEMI?

  -Initial evaluation of pat.

  -Initially pat. assessed for indictions of perfusion therapy

  -If indications not present, then pat is monitored & evaluated for ACS & therapy is guided by risk stratification

  -Chest pain, ECG, cardiac biomarkers, pain relief

  -First objective of evaluation is to determine whether ACS is the actual cause of pats. presentation

  -Most pats w/ ACS will present w/ Hx of prolonged or recurrent chest discomfort, others may present w/ atypical symptoms:

  -neck, jaw, back or epigastric discomfort

  -Excessive sweating, N & V

  -Atypical presentation more common in elderly, diabetics & women

  -ECG may be normal or show minor changes in uptown 50% of cases

  -Second objective to determine risk of short term adverse outcomes:

  -Pats are effectively evaluated & treated based on 6 month risk of death or mI
• Which scoring system used to assess 6-month mortality or risk of CV event?

  GRACE
• How is likelihood of evolving ACS & other causes of chest pain evaluated?

  -Clinical history, examination, ECG, chest x-ray

  -High sensitivity troponin tests performed on all pats.