Statins + SVT + Takayasu's arteritis

Question 1

What is the MOA of statins?

Answer 1

Statins inhibit the action of HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis.

Question 2

What adverse effects can statins have?

Answer 2

1. Myopathy: includes myalgia, myositis, rhabdomyolysis and asymptomatic raised creatine kinase.
   
   • Risks factors for myopathy include advanced age, female sex, low BMI and presence of multisystem disease such as diabetes mellitus.
   • Myopathy is more common in lipophilic statins (simvastatin, atorvastatin) than relatively hydrophilic statins (rosuvastatin, pravastatin, fluvastatin)
2. Liver impairment: the 2014 NICE guidelines recommend checking LFTs at baseline, 3 months and 12 months. Treatment should be discontinued if serum transaminase concentrations rise to and persist at 3 times the upper limit of the reference range
3. Increase the risk of intracerebral haemorrhage in patients who’ve previously had a stroke. This effect is not seen in primary prevention :. recommend avoiding statins in patients with a history of intracerebral haemorrhage

Question 3

What are the contraindications of statins?

Answer 3

1. Macrolides (e.g. erythromycin, clarithromycin) are an important interaction.
2. Statins should be stopped until patients complete the course
3. Pregnancy

Question 4

Who should receive a statin?

Answer 4

1. All people with established CVD
2. Anyone with a 10-year cardiovascular risk >= 10%
3. Type 2 diabetes mellitus should now be assessed using QRISK2 like other patients are, to determine whether they should be started on statins
4. Patients with type 1 diabetes mellitus:
   
   • who were diagnosed more than 10 years ago
   • are aged over 40
   • have established nephropathy

Question 5

When should statins be taken?

Answer 5

• Statins should be taken at night as this is when the majority of cholesterol synthesis takes place
• This is especially true for simvastatin which has a shorter half-life than other statins

Question 6

What is NICE’s recommendation for prevention of CVD?

Answer 6

Question 7

What is the path of the subclavian artery?

Answer 7

1. The left subclavian comes directly off the arch of aorta
2. The right subclavian arises from the brachiocephalic artery (trunk) when it bifurcates into the subclavian and the right common carotid artery.
3. From its origin, the subclavian artery travels laterally, passing between anterior and middle scalene muscles, deep to scalenus anterior and anterior to scalenus medius.
4. As the subclavian artery crosses the lateral border of the first rib, it becomes the axillary artery
5. At this point it is superficial and within the subclavian triangle.

Question 8

What are the branches of the subclavian artery?

Answer 8

1. Vertebral artery
2. Internal thoracic artery
3. Thyrocervical trunk
4. Costocervical trunk
5. Dorsal scapular artery

Question 9

What is supraventricular tachycardia?

Answer 9

• Refers to any tachycardia that is not ventricular in origin the term
• Generally used in the context of paroxysmal SVT (acute start and end)
• Episodes are characterised by the sudden onset of a narrow complex tachycardia, typically an atrioventricular nodal re-entry tachycardia (AVNRT)
• Other causes include atrioventricular re-entry tachycardias (AVRT) and junctional tachycardias.

Question 10

What is the acute management of SVT?

Answer 10

1. Vagal manoeuvres: e.g. Valsalva manoeuvre, carotid sinus massage
2. Intravenous adenosine 6mg → 12mg → 12mg:
   
   • contraindicated in asthmatics - verapamil is a preferable option
3. Electrical cardioversion

Question 11

How do you prevent SVT?

Answer 11

1. Beta-blockers
2. Radio-frequency ablation

Question 12

What is the definition of syncope?

Answer 12

Syncope may be defined as a transient loss of consciousness due to global cerebral hypoperfusion with rapid onset, short duration and spontaneous complete recovery.

Question 13

What is takayasu’s arteritis?

Answer 13

• Takayasu’s arteritis is a large vessel vasculitis
• It typically causes occlusion of the aorta and questions commonly refer to an absent limb pulse
• It is more common in females and Asian people

Question 14

What are the features of takayasu’s arteritis?

Answer 14

1. Systemic features of a vasculitis e.g. malaise, headache
2. Unequal blood pressure in the upper limbs
3. Carotid bruit
4. Intermittent claudication
5. Aortic regurgitation (around 20%)

Question 15

What is takayasu’s arteritis associated with?

Answer 15

Renal artery stenosis

Question 16

What is the management of takayasu’s arteritis?

Answer 16

Steroids