acute coronary syndromes

what 4 problems are related to heart disease

problems relating to:

weakness of the heart pumping

valve problems

rhythm of the heart

coronary artery disease

coronary disease can…

• be completely silent

• cuase myocardial ischemia

• if prolonged myocardial ischaemia can be enough to cause cell death

what is an acute coronary syndrome

recent onset of symptoms related to a problem with the coronary arteries

what is stable angina

• caused by stable coronary lesion

• predictable symptoms due to narrowing

• symptoms relieved by rest

what is acute coronary syndromes caused by

• unstable coronary lesion

• is unpredictable and may occur at rest

in classification of acute coronary syndromes what does evidence of cell death indicate

a myocardial infarction

in classification of acute coronary syndromes what does n evidence of cell death indicate

unstable or crescendo angina

define the term heart attack

often used by doctors to patients/ public to mean a myocardial infarction

what do the public often use the term heart attack to mean and what is the actual term for this

sudden death/aborted death related to a sudden heart problem, this is actually called a cardiac arrest

what is a cardiac arrest

when the heart is not producing enough output to be able to sustain life

what is a cardiac arrest often due to

a sudden change in heart rhythm incompatible with life ot something else affecting heart function, meaning it is not able to pump out enough blood to sustain life

development of coronary heart disease

1. asymptomatic atherosclerotic plaque

2. stable fixed atherosclerotic plaque- stable angina

3. unstable plaque, plaque disruption and platelet aggregation- unstable angina

4. small thrombus- non-ST-segment elevation MI

5. larger thrombus- obstructing the whole lumen- ST-segment elevation MI

how to diagnose a myocardial infarction

detection of cardiac cell death: +ve cardiac biomarkers

AND ONE OF:

• symptoms of ischaemia- chest pain and tightness

• new ECG changes

• evidence of coronary problem on coronary angiogram or autopsy

• evidence of new cardiac damage on another test

why is troponin a good marker of cardiac injury

because it is highly specific to cardiac muscle and is only released into the bloodstream when myocardial cells are damaged and this can be picked up by specific tests

what are other causes other than myocardial injury that can cause a troponin rise

• coronary atherosclerosis

• coronary artery spontaneous tearing

• coronary artery spasm- eg. after cocaine ingestion

• myocardial inflammation- myocarditis or takotsubo cardiomyopathy (broken heart syndrome)

• strain on the heart- arrythmia, pulmonary embolism

• biomarkers leaking out of myocardial cells- sepsis

type 1 MI

spontaneous MI associated with ischemia and due to a primary coronary event such as plaque erosion, rupture, fissuring or dissection

type 2 MI

due to imbalance in supply and demand of oxygen. Result of ischemia but not ischemia from thrombosis of coronary artery

type 3 MI

sudden cardiac death, including cardiac arrest, with syptoms of ischemia, accompanied by new ST elevation or LBBB. verified coronary thrombus by angiography or autopsy but death occuring before blood samples could be obtained or before biomarkers appear in the blood

type 4a MI

MI associated with percutaneous coronary intervention. PCI-related increase of biomarkers greater than 3 X 99th percentile of the upper reference limit is by convention defined MI

type 4b MI

MI associated with verified stent thrombosis via angiography or autopsy

type 5 MI

MI associated with CABG >5 X 99th percentile upper reference limit plus Q waves or LBBB or imaging evidence of new loss

differnt causes of MI

plaque rupture thrombus- type 1

vasospasm or endothelial dysfunction- type 2

fixed atherosclerosis- type 2

supply demand imbalance alone- type 2

history of acute coronary syndrome

chest pain that sounds like related t myocardial ischaemia

• often deny it is a pain, more discomfort or a weight or tightening

• may radiate to neck/arm

• may be associated with nausea, sweating and breathlessness

what are cardiac risk factors

• male

• age

• known coronary disease

• high blood pressure

• high cholesterol

• diabetes

• smoker

• family history of premature heart disease

examination of acute coronary syndrome

• may look very unweel if having a STEMI

• may look completely fine if not

• often no specific examination features to find

• ensure that you check

  • HR,BP- comparing arms- aortic dissection

  • listen for murmurs- significant valve problem

  • listen for crackles- heart failure

what are key investiagtions

prompt ECG and biomarker release

what is the ECG in a complete coronary occlusion

initial ECG- ST elevation

ECG at 3 days- Q waves

what is an ECG in partial coronary occlusion

initial ECG- ST depression, T wave inversion, may be normal

ECG at 3 days- No Q waves

posterior MI

as the posterior wall supplied bu the left circumflex which goes round the back of the heart, may not see any ST elevatin even if the LCx is completely blocked

dont usually put ECG leads on back of the chest so easily missed

but will see opposite changes in the leads opposite those looking at that area

STEMI

ST elevation myocardial infarction

• ‘full blown’ heart attack

• likely they have a completely blocked coronary artery

• ongoing myocardial cell death

• need to get the artet opened ASAP

immediate reperfusion therpay of STEMI

mechanical- in cath lab with balloons and stents- primary percutaneous coronary intervention

pharmacological- with a very long strong blood clot dissolving drug

what is angioplasty

Angioplasty is a minimally invasive procedure that uses a balloon catheter to widen narrowed or blocked arteries, often with the placement of a stent to restore blood flow

thrombolysis

very strong blood clot dissolving medication- can be given anywhere

often will then arrange prompt transfer to a cardiac centre with a cath lab

what are the risks of thrombolysis

• bleeding

• don’t give if recent stroke, or ever had a previous intracranial bleed

• caution if had recent surgery, on warfarin, severe hypertension

deciding between thrombolysis or cath lab for STEMI

• thrombolysis works well if given early

• thrombolysis more likely to cause bleeding problems

• so generally cath lab is better

• but it depends how far away this cath lab is

management of NSTEMI

• admit to hospital

• attach to a cardiac monitor

• gain IV access

• give O2 only if levels low

investigations for NSTEMI

• serial ECGS

  • repeat ECG if not sure if there are any changes

  • think abut doing posterior leads

  • don’t want to miss an evolving STEMI or posterior STEMI

• blood tests

  • check troponin

  • now can do immediate “point of care” test

  • check for Hb, kidney function, cholesterol

treatment of ACS

• glycerol trinitrate

  • vasodilator- opens up coronary arteries

  • can give sub-lingal, or as continuous intravenous infusion if ongoing chest pain

  • wont help if the artery is completely blocked

• analgesia

  • opiates

  • helps relieve anxiety too

  • also help venodilate which may have hemodynamic benefits

anti-thrombotic drugs

dual anti-platelt therapy

• aspirin: 300mg laoding dose (unless already on), then 75mh od

  plus one of the P2Y12 receptor antagonists

• clopidogrel: 300mg loading dose, then 75 mg od or

• ticagrelor: 180mg loading dose, then 90mg od or

• prasugrel: 60mg loading dose then 10mg od

anti-coagulant drugs (given as an injection

• heparin: given as infusion, monitor APTTr

• LMWH: s/c injection once or twice a day

• fondaparinux: 2.5mg od s/c

beta blockers

reduce the work the heart has to fo

beneficial acutely

also reduced the risk of further cardiac events longer term

eg. bisoprolol 2.5mg od

statins

cholesterol lowering drugs

evidence that the lower the cholesterol level

eg. atrovastatin 80 mg od

ACE inhibitors

helps heart muscle recover

eg. ramipril 2.5mg od

should patients with non ST elevatin ACS also have a coronary angiogram

there is evidence to show that those will benefit from early invasive strategy

most patients will get an angiogram unless it seems more likely to be a type II MI, or if the risks of the procedure seem too high

ideally should be done within 48 hours

what is the aim of a coronary artery bypass graft

The aim of coronary artery bypass grafting (CABG) is to restore blood flow to the myocardium by bypassing narrowed or blocked coronary arteries, using a graft (typically from the saphenous vein, internal mammary artery, or radial artery) to improve oxygen supply, relieve angina, and reduce the risk of myocardial infarction and heart failure.

risks of coronary angiography and percutaneous coronary intervention

• die can affect kidney function

• bleeding from arterial access site

• stroke

• myocardial infarction

• coronary perfoatin

• need for emergency CABG

ongoing ACS management in hospital

keep attached to cardiac monitor for first 24-48 hrs

listen for new murmurs and signs of heart failure every day

start secondary prevention medications

organise an echocardiagram

mechanical complications

can have major problems relating to issues with the damaged heart muscle, esp. after STEMI

• myocardial rupture- bleed int pericardium- causes cardiac tamponade

• acute ventricular septal defect

• mitral valve dysfunction due to papillary muscle rupture

always listen fr development of a NEW loud murmur

what is the course taken in hospital

• used to be confined t bed for weeks fllowing an MI

• now usually home within 2-3 days if uncomplicated

• ensure seen by cardiac rehibilitation nurses

• advise about lifestyle measure including smoking, driving, going back to work

• reinforce importance of medication escp during DAPT

• arrange follow up