Cardiothoracic Surgery

Question 1

gold standard imaging technique for heart visualisation

Answer 1

Coronary angiography

Question 2

gated imaging technique for heart visualisation

Answer 2

CT angiography

Question 3

imaging techniques for heart visualisation

Answer 3

ECG
Echo
Coronary angiography
CT angiography
MRI

Question 4

how to put a patient on cardiopulmonary by-pass (on-pump)?

Answer 4

• hole in right atrium to remove blood
• heparinise the blood (per kg) to stop coagulation in the tube, test doing activated clotting time (ACT)
• the blood removed needs and oxygenator (increase O2) and a pump (increase pressure)
• return blood to aorta

Question 5

why put a patient on by-pass?

Answer 5

need to support organ perfusion

able to manipulate:
- flow and pressures
- temperature (DHCA)

Question 6

what is cardiac index?

Answer 6

ability for heart to pump sufficient blood
approx. 2.4L per surface area

Question 7

What is a CABG procedure?

Answer 7

coronary artery bypass graft - involves using a graft blood vessel taken from elsewhere in the body (usually the saphenous vein.

Question 8

What does the LCA divide into?

Answer 8

Left coronary artery (LCA) becomes the circumflex and left anterior descending arteries

Question 9

What does the RCA supply?

Answer 9

right atrium
right ventricule
inferior aspect of the left ventricle
posterior septal area

Question 10

What does the circumflex artery supply?

Answer 10

left atrium
posterior aspect of the left ventricle

Question 11

What does the left anterior descending artery supply?

Answer 11

Anterior aspect of the left ventricle
Anterior aspect of the septum

Question 12

What is atherosclerosis?

Answer 12

Atheromas (fatty deposits in the artery walls)
and sclerosis (the process of hardening of the blood vessel walls)

Question 13

Which arteries does atherosclerosis affect?

Answer 13

Medium and large arteries

Question 14

What causes atherosclerosis?

Answer 14

chronic inflammation and activation of the immune system in the artery wall.

Lipids are deposited in the artery wall, followed by the development of fibrous atheromatous plaques.

plaques stiffen the walls, causing hypertension and strain on the heart

stenosis causes reduced blood flow (angina)

plaque rupture can cause a thrombus and ischaemia (ACS)

Question 15

conditions caused by atherosclerosis

Answer 15

angina
myocardial infarction
transient ischaemic attack
stroke
peripheral arterial disease
chronic mesenteric ischaemia

Question 16

management of coronary artery disease

Answer 16

medical: secondary prevention with statins, aspirin, beta-blockers and ACE inhibitiors
surgical: PCI with coronary angioplasty and CABG
conservative: smoking cessation, diet, exercise, alcohol consumption, sleep, stress

Question 17

What is cardioplegia?

Answer 17

temporary stopping of the heart after cardiopulmonary bypass

Question 18

What drug is used for cardioplegia?

Answer 18

Plegisol - high potassium solution delivered into the coronary circulation

Question 19

What are the three main blood vessel options for CABG?

Answer 19

saphenous vein
internal thoracic artery - from subclavian artery
radial artery

Question 20

Why are arterial grafts preferential to vein grafts?

Answer 20

Vein grafts have a tendency to become stenosed in a process called intimal hyperplasia. The tunica intima layer in the vessel becomes thickened, mostly due to increased pressure.