case 9 - chest pain

Question 1

Which blood vessels develop atherosclerotic plaques?

Answer 1

Elastic arteries, and large/medium muscular arteries

Question 2

What is the pathophysiological process of the formation of atherosclerotic plaques?

Answer 2

1.) endothelial cell injury increases vascular permeability, platelet adhesion and leukocyte recruitment
2.) lipoproteins, particularly oxidised LDL, seep into arterial intima
3.) cytokines released, attracts monocytes which take up LDL forming foam cells.
4.) smooth muscle cells proliferate and deposit ECM, then become foam cells. T cells are recruited.

Question 3

What are the key gross features of an atherosclerotic plaque?

Answer 3

Fibrous cap on media of artery, underlying lipid core/necrotic centre with lipids and inflammatory cells

Question 4

Which type of lipoprotein is associated with the development of atherosclerotic plaques?

Answer 4

(oxidised) LDL

Question 5

What is a myocardial infarction?

Answer 5

A cardiac event in which blood flow is obstructed to a region of myocardium, causing cell death.

Question 6

What are the key stages in the development and progression of a myocardial infarction?

Answer 6

Atherosclerotic plaque development, plaque rupture/acute plaque change, coronary artery occlusion, ischaemia, infarction, inflammatory response, fibrosis

Question 7

Why can acute plaque change cause an MI?

Answer 7

Exposure of the necrotic centre of plaque causes coagulation, forming a thombus that can occlude the vessel.

Question 8

What is an infarction of the heart?

Answer 8

When ischemia of the myocardium causes permanent damage, causing necrosis of the issue and the release of troponins and inflammatory mediators into the blood stream.

Question 9

What type of necrosis occurs at a myocardial infarct?

Answer 9

Coagulative necrosis

Question 10

What process do MIs heal through?

Answer 10

Fibrosis - forms a collagenous, fibrous scar

Question 11

What features of a patient history may suggest MI?

Answer 11

Smoking, hypercholesterolaemia, history of MI

Question 12

What is the most significant symptom of MI?

Answer 12

Chest pain

Question 13

How is MI chest pain often described?

Answer 13

Crushing pain, with radiation to the mandible and left arm

Question 14

What are the symptoms associated with MI?

Answer 14

nausea, sweating, lightheadedness, tachycardia

Question 15

What imaging techniques can be used to diagnose MI?

Answer 15

Coronary angiography, echocardiography

Question 16

Which cardiac biomarkers indicate probable MI?

Answer 16

troponin (CTn1), creatine kinase-MB

Question 17

What ECG changes are present in a STEMI?

Answer 17

Significant and persistent ST segment elevation or anterior ST segment depression

Question 18

What ECG changes are present in a NSTEMI?

Answer 18

ST segment depression or T wave inversion

Question 19

During exercise stress testing, what does ST segment depression indicate?

Answer 19

Reversible myocardial ischaemia

Question 20

What are the ECG changes visible during symptomatic episodes of stable angina?

Answer 20

ST depression

Question 21

What are the key differences between an episode of stable angina vs a myocardial infarction?

Answer 21

Myocardial infarction:
can come on at rest, lasts longer, not relieve by nitrate sprays, troponin.ck-mb positive, ST elevation

Question 22

What are the non-modifiable risk factors for CVD?

Answer 22

Genetic predisposition, family history, increased age, male gender, history of CVD

Question 23

What are the modifiable risk factors for CVD?

Answer 23

Smoking, hypertension, LDL cholesterol, sodium intake, Diabetes Mellitus type II, stress, alcoholism, physical inactivity, obesity, inflammation

Question 24

What are the ways that hypertension increases the risk of CVD?

Answer 24

damage to endothelium causes plaques to form, increased resistance to pumping causes ventricular hypertrophy, increased risk of plaque rupture and embolism/MI, high pressure stretches arterial walls causing aneurysms

Question 25

What is the immediate treatment for stable angina?

Answer 25

Vasodilator - usually glyceryl trinitrate sublingual spray for rapid symptoms relief

Question 26

What are the short term/complication reducing treatments for stable angina?

Answer 26

Antiplatelet agent, e.g. low dose aspirin.

Question 27

What are the long term management strategies for stable angina?

Answer 27

statin, antihypertensives, dietary changes, green prescription, exercise, smoking cessation.

Question 28

What are the ratios of fuel sources used for cardiac metabolism in adults in a normal state?

Answer 28

70% carbohydrates, 30% lipid

Question 29

What is fuel utilization in cardiac metabolism modulated by?

Answer 29

Substrate availability, hormones, oxygen availability, workload/exercise

Question 30

Which hormones modulate fuel utilization in cardiac metabolism?

Answer 30

Insulin, glucagon

Question 31

Which type of metabolism does the heart usually utilise?

Answer 31

Oxidative metabolism - citric acid cycle drives the electron transport chain

Question 32

What is the main substrate of cardiac metabolism in the fed state?

Answer 32

Carbohydrates

Question 33

What is the main substrate of cardiac metabolism in the fasting state?

Answer 33

Lipids/fatty acids

Question 34

How does cardiac metabolism change in the ischemic heart?

Answer 34

Oxidative metabolism drops due to poor O2 supply, the heart relys of glycolysis (an anaerobic process using glucose)

Question 35

What are some of the classes of medicines used to ease symptoms/prevent complications in the treatment of MI?

Answer 35

nitrates for vasodilation, opioids for pain, fibrinolytics to break down thrombi, antiemetic for nausea/vomiting, anticoagulants to prevent thrombus formation

Question 36

What medicines are used to prevent further complications in MI treatment?

Answer 36

Statins, dual antiplatelet therapy

Question 37

What is the key medicine used to alter disease progression following MI?

Answer 37

ACE inhibitors - an antihypertensive

Question 38

What is the role of fibrinolytics in MI treatment?

Answer 38

Administered after MI diagnosis, help to break down clots/thrombi

Question 39

What is the basic mechanism of action of fibrinolytics?

Answer 39

They facilitate the conversion of plasminogen to plasmin, which is an enzyme that helps to break down fibrin in clots.

Question 40

Which fibrinolytic is typically used for MI treatment?

Answer 40

Tenecteplase

Question 41

Which anticoagulant (LMWH) is typically used in MI treatment?

Answer 41

Enoxaparin

Question 42

What are the trends in IHD mortality in NZ from the 1940s to present?

Answer 42

From 1940s to 1960s there was an upward trend is IHD, then afterwards there was a decline in mortality. This trend was observed in males and females, though males have a higher rate of mortality.

Question 43

Which sex has a greater prevalence of IHD mortality?

Answer 43

Male

Question 44

What are some of the reasons for declining IHD mortality since the 1960s?

Answer 44

treatment advances, emergency infrastructure, preventative medications, tobacco control, diet/exercise awareness, primary care screening

Question 45

What is a green prescription?

Answer 45

A health intervention aimed at providing individuals/whanau with tools to improve their lifestyle and health.