Cardiovascular Risk Factors

Question 0

Which is more common, primary or secondary hypertension?

Answer 0

Primary (~90% of cases)

Question 1

How is hypertension diagnosed?

Answer 1

Clinic BP is 140/90 or higher
- Take a second measurement
Ambulatory BP is 135/85 or higher
- Hypertension confirmed

Question 2

What are some secondary causes of hypertension?

Answer 2

Renal/Endocrine/Aortic disease
Renal artery stenosis
Drug therapy

Question 3

How does renal artery stenosis cause hypertension?

Answer 3

Decreased renal blood flow
Excess renin secretion
Huge sodium and water retention - plasma volume increases

Question 4

What is Conn’s syndrome?

Answer 4

Excess aldosterone

Question 5

What is Cushing’s syndrome and how does it present?

Answer 5

Excess corticosteroid

Weight gain, rounded face etc

Question 6

What can hypertension lead to?

Answer 6

LVH
CCF
Atheroma
Aneurysm rupture (Berry aneurysm - subarachnoid haemorrhage - thunderclap headache)

Question 7

What is pre-eclampsia?

Answer 7

Hypertension and proteinuria in pregnancy

Resolves after birth

Question 8

What can result due to cardiac Ischaemia?

Answer 8

Angina
Infarct
Cardiac failure

Question 9

How is the heart affected when fibrosis occurs?

Answer 9

Loses elasticity

Decreased EDV and hence decreased SV

Question 10

What can occur if the carotid arteries become stenosed?

Answer 10

TIAs
CVAs
Vascular dementia

Question 11

What can cause an aneurysm can form?

Answer 11

Congenital causes
Syphilis
Mycotic - bacterial infection of artery wall
Iatrogenic
Copper deficiency

Question 12

What is the difference between a true aneurysm and a pseudoaneurysm?

Answer 12

True aneurysm
- Involves all three layers of arterial wall
Pseudo
- Blood leaking completely out of artery into surrounding tissues

Question 13

What is an arterial dissection?

Answer 13

Tunica media split by blood

Question 14

What colour is an arterial thrombus?

Answer 14

White - mainly platelets in fibrin mesh

Question 15

What colour is a venous thrombus?

Answer 15

Red

Question 16

What happens in the coagulation cascade?

Answer 16

Factor X — Factor Xa

Factor Xa stimulates Prothrombin (II) — Thrombin (IIa)

Thrombin stimulates Fibrinogen (soluble) — Fibrin (insoluble)

Fibrinogen and Thrombin cause platelet aggregation

Question 17

Why is and what form is vitamin K required for coagulation?

Answer 17

Used in production of carboxylase enzyme
Reduced form (Hydroquinone)

Question 18

What reaction does carboxylase enzyme mediate?

Answer 18

Activation of precursors (II, VII, IX and X) to gamma-carboxyglutamic acid residues (serine proteases)

Question 19

How does warfarin work?

Answer 19

Prevents reduction of Vitamin K back to hydroquinone by competing for vitamin k reductase

Question 20

What does Antithrombin III do?

Answer 20

Neutralises serine proteases

Question 21

How does heparin work?

Answer 21

Binds to ATIII

Increases its affinity for serine proteases (esp IIa and Xa)

Question 22

How do low molecular weight heparins work?

Answer 22

Inhibit factor Xa

Question 23

Heparin or LMWH; when is each preferred?

Answer 23

Heparin
- Renal failure since LMWH is excreted by the kidneys
LMWH
- In outpatient treatment as it can be given subcutaneously
- Huge PE due to more predictable pharmacokinetics

Question 24

What chemicals cause platelet aggregation and how?

Answer 24

``` ADP 5-hydroxytryptamine (5-HT) Thromboxane A2 (TXA2) ``` Cause expression of GPIIb/IIIa receptors - cross link platelets via fibrinogen

Question 25

How does aspirin work?

Answer 25

Blocks COX-1 irreversibly Prevents TXA2 synthesis Less GPIIb/IIIa expression Less cross linking

Question 26

How does tirofiban work?

Answer 26

Blocks the GPIIb/IIIa receptors | Prevents fibrinogen cross-linking of platelets

Question 27

How does clopidogrel work?

Answer 27

Blocks P2Y12 receptor irreversibly ADP cannot bind to and activate receptor Decreased GPIIb/IIIa expression Less cross linking

Question 28

How does plasminogen work?

Answer 28

Converted to plasmin Promotes conversion of fibrin to fibrin fragments Clot lysis

Question 29

What does streptokinase act as and how?

Answer 29

A fibrinolytic extracted from streptococci | Stimulates conversion of plasminogen to plasmin

Question 30

What patients is streptokinase not suitable in?

Answer 30

Patients with strep infection | Patients who have received it for longer than 4 days - antibodies produced

Question 31

Give examples of tPAs and explain how they work?

Answer 31

Alteplase and Duteplase Convert fibrin-bound plasminogen to plasmin - Selective for clots

Question 32

How can fibrinolytic drug overdose be treated?

Answer 32

Tranexamic acid | Inhibits plasmin production

Question 33

What are some special adaptations of the coronary circulation?

Answer 33

High capillary density High basal blood flow High oxygen extraction into tissues

Question 34

What effect does decreased PaO2 have on coronary arteries?

Answer 34

Vasodilation

Question 35

What effect does adenosine have on coronary arteries?

Answer 35

Vasodilation

Question 36

The coronary arteries are supplied by sympathetic nerves, why don't they vasoconstrict?

Answer 36

Over-ridden by metabolic hyperaemia - functional sympatholysis Adrenaline activates Beta2 receptors - vasodilation

Question 37

What happens to coronary flow if diastole is shortened?

Answer 37

Decreased coronary flow

Question 38

What do the internal carotids and vertebral arteries combine to form?

Answer 38

Basilar artery

Question 39

What is the circle of Willis?

Answer 39

An anastomosis of the basilar artery and internal carotid arteries - Maintains perfusion if one carotid occluded

Question 40

Between what BPs can autoregulation protect the brain against MAP changes?

Answer 40

60-160

Question 41

What happens if intracranial pressure increases?

Answer 41

Decreased cerebral perfusion pressure | Decreased blood flow

Question 42

Why, in hypoxia, do pulmonary arteries vasoconstrict instead of dilate like everywhere else in the body?

Answer 42

To divert blood away from poorly oxygenated alveoli | - Blood taken to areas rich in oxygen to maintain gas exchange

Question 43

Why does skeletal muscle blood flow increase during exercise?

Answer 43

Local hyperaemia overcomes SNS vasoconstrictor tone Adrenaline - Beta2 receptors - Vasodilation Increased cardiac output - increased blood flow