Coronary Artery Disease

Question 1

How can Coronary ARtery Disease present?

Answer 1

pain

arrhythmia

mechanical complications like mitral regurg, pump failure, mitral regurg ,myocardial rupture, ventricular septal rupture

Question 2

what is the criteria for diagnoses of an Acute MI?

Answer 2

1. Detection of a rise/fall of cardiac biomarker values preferably cardiac troponin (I or T) with at least one of the following
   
   1. ischaemic symptoms
   2. ECG changes
   3. Development of pathologic Q waves in ECG
   4. imaging evidence of new loss of myocardium or regional wall abnormality
   5. identification of an intracoronary thrombus by angiography or autopsy

Question 3

what can caused a raised cardiac troponin other than MI?

Answer 3

cardiac surgery

myocarditis

cardiotixc agents like Herceptin

heart Failure

stress cardiomyopathy

severe PE

sepsis

renal failure

stroke

strenuous exercise

Question 4

what are the different ‘types’ of MI?

Answer 4

• Type 1= spontaneous MI related to atherosclerotic plaque rupture, ulceration, fissuring, erosion or dissection with resulting intraluminal thrombus
• Type 2 = Mi secondary to ischaemic imbalance - ie) coronary endothelial disfunction, coronary artery spasm, coronary embolism, anaemia, resp. failure, hypotension etc.

Question 5

what diagnoses fall under ‘acute coronary syndrome’?

Answer 5

unstable angina = troponin negative

and

acute MI = troponin positive

Remember the only differece between unstable angina and acute MI is cardiac necrosis (troponin)

Question 6

what part of the cardiac muscle is the first to experience necrosis?

Answer 6

the ENDOcardium b/c it’s the furthest away from the vessel

Question 7

What is a ‘collateral’ blood flow as it pertains to ischaemia of the cardiac muscle?

Answer 7

when the heart muscle experiences chronic ischamia, over time it reopens fetal vessels to divert blood and provide the muscle with ‘it’s own natural bypass’

Question 8

How do we diagnose coronary artery disease?

Answer 8

History

Examination

Investigations

Question 9

How do we treat coronary artery diseae?

Answer 9

‘diet - less fats/cholesterol

Drugs -

Devices (stents, bypass)

Question 10

in a stable patient with coronary artery disease, what would you find on examination?

Answer 10

in stable patient - might be entirely normal upon examination

OR

• may have tachycarida if pain
• BP may be high with pain or low if severe ischamia with rhythm or pump problem

chest may show signs of pulmonary congestion

may have 3rd heart sound

Question 11

how do we diagnose coronary artery disease using laboratory techniques?

Answer 11

• get haemoglobin first, cholesterol, thyroid function, kidney function (before ACE inhibitor)
• cardica Ck and Troponin
• Radiological imaging

Question 12

Describe how Troponin is used to diagnose coronary artery disease?

Answer 12

Troponin - is a cytoskeletal protein that enters circulation when necrosis occurs

it may be normal within the first 2-4 hours of acute infarction

stays elevated for 2-4 weeks

Question 13

If someone comes in with chest pain and they have a raised ST segment elevation, what diagnoses OTHER than MI do you have on your differential?

Answer 13

• aortic dissection
• PE
• Coronary spasm

Question 14

What ECG leads do we look for ST segment elevation in?

Answer 14

in the leads V2 and V3

Question 15

why might a subarachnoid haemorrhage cause an ST elevation?

Answer 15

b/c a bleed in the brain can release mad amounts of catecholamines which effect the ECG reading

Question 16

What is our treatment for a STEMI?

Answer 16

• stabilize patient (ABCD)
• load with antiplatelet agent and anti-coagulate
  
  • aspirin 300mg
  • Clopidogrel 300mg
• Statin to stabilize plaque
• Cath Lab - mechanically open blockage via Primary Percutaneous Intervention (PPCI)
• intravenous Heparin given 700 units/kg

Question 17

if there is ST elevation in ‘anterior’ leads (V1-V5/6), which artery is typically effected?

Answer 17

Left Anterior Descending

Question 18

if there is ST elevation in ‘lateral leads’ (aVL, I, V6) which artery is typically effected?

Answer 18

Left circumflex

or diagonal

Question 19

If there is ST elevation in the ‘inferior leads’ (2,3,avF) which artery is typically effected?

Answer 19

85% Right coronary artery

or

15% Left Circumflex

Question 20

ST depression in V1-V3 leads is indicative of a blockage in what artery?

Answer 20

‘posterior MI’

Left circumflex artery or right Coronary

Question 21

how does treatment differ if STEMI or NSTEMI?

Answer 21

STEMI = PCI within 12 hours of pain onset or thrombolysis ASAP

NSTEMI= not usually urgent angiogram unless instability or patient devellops ST segment elevation (cath lab usually defered 24-48 hours) ex) unstable angina treated as NSTEMI

Question 22

Do we provide coronary angiography for patients with stable angina?

Answer 22

no - fixing the issue doesn’t necessarily improve outcomes - so we meticulously control with diet and drugs, blood pressure, cholesterol etc.

Question 23

Other than thrombolysis or PCI, what can we do mechanically to treat a Coronary Artery Disease?

Answer 23

• CABG = when multi-vessel disease
• Diabetes with Triple vessel disease (controversial)
• patients who cannot take uninterrupted dual anti-platelet therapy
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