PBL1: Jonathan Chalmers

Question 1

What is a systolic murmur?

Answer 1

Heard in aortic stenosis and mitral regurgitation and coarctation of the aorta. Sound is heart after S1 (mitral and tricuspid valves shut) and before the end of S2 (aortic and pulmonary valves shut) as there is incomplete/delay closing of the aortic valve.

Question 2

Where do you listen for a systolic murmur?

Answer 2

Right 2nd intercostal space where aortic valve would be

Question 3

What is coarctation of the aorta?

Answer 3

A narrowing of the aorta normally near the ductus arteriosus and distal to the origin of the left subclavian artery.

Question 4

What are the types of coarctation of the aorta? How do they differ?

Answer 4

Pre ductal - proximal to the ductus arteriosus (means there is still sufficient blood flow to perfuse the body and legs)
Ductal - when the ductus arteriosus closes
Post ductal - distal to the ductus arteriosus (poor perfusion to body and legs so rely on collateral circulation)

Question 5

How is coarctation of the aorta caused?

Answer 5

Defect in the development of the 4th and 6th aortic arches. Leads to a posterior shelf forming as the tunica media undergoes posterior infolding. Aorta circumference extends so it can twist/turn/become tortuous.

Question 6

What are the main symptoms?

Answer 6

Congestive heart failure in early life
Hypertension
Headaches
Nosebleeds
Leg cramps
Muscle weakness
Cold feet
Neurological signs

Question 7

Explain why individuals get congestive heart failure during early life.

Answer 7

There is insufficient pumping of blood as it tries to pass through and against the narrowed aorta resulting in a build up of fluid. This leads to acidosis and poor perfusion.

Question 8

Explain the headaches, nosebleeds and hypertension

Answer 8

Increased flow in arteries leaving the heart from the aorta where it is forced past the constriction resulting in greater pressures.

Question 9

Explain the leg cramps, muscle weakness and cold feet.

Answer 9

Reduced flow to the lower body as there is not enough blood leaving the heart due to constriction and low pressure.

Question 10

What is seen in histology?

Answer 10

• Medial lesions as thickening ridges protrude into the aortic lumen
• Elastic tissue disruption distal to the coarctation
• Innermost aortic wall injured so blood flows between the layers blocking other arteries and causing ruptured aneurysms

Question 11

What are the main diagnostic methods?

Answer 11

Physical Exam
Chest X ray
Barium Oesophagram
Doppler ultrasound

Question 12

What is looked for on a physical exam?

Answer 12

Blood pressure difference between the upper and lower limbs
Pulse delay between upper and lower limbs
Diminished peripheral distal pulses
Left arm may be smaller causing low blood pressure
Auscultate for a systolic murmur

Question 13

Why may the left arm be smaller?

Answer 13

Subclavian artery may be compromised reducing blood flow to muscles there resulting in muscle wasting because of hypoxia and necrosis.

Question 14

What would a chest x-ray show?

Answer 14

Cardiac enlargement

Pulmonary venous congestion

Question 15

What would a barium esophagram show?

Answer 15

Classic E signs as the oesophagus is compressed from the dilated left subclavian artery
Post stenotic dilatation in the descending aorta

Question 16

What would a doppler ultrasound show?

Answer 16

blood pressure difference in the aorta

Question 17

What are some complications of coarctation of the aorta?

Answer 17

• Impaired diastolic left ventricular function
• Persisting myocardial hypertrophy
• Aortic stenosis
• Ventricular septal defects
• Aortic arch hyperplasia
• extra cardiac nonvascular abnormalities in 25%

Question 18

How must it be monitored in the future?

Answer 18

Blood pressure should be checked every 1-2 yeas post repair as there is an increased risk of developing hypertension and aortic valve problems

Question 19

What is the prognosis?

Answer 19

if not treated less than 20% reach 50 yrs

if repaired before 14 years 91% survival rate
if repaired after 14 years, 79% survival rate

Question 20

What may patients need advice on?

Answer 20

Exercise

Endocarditis and endarteritis prevention

Question 21

What are the main treatment methods?

Answer 21

• resection (remove coarctation site and end-end anastomose)
• patch angioplasty (cut obstruction and replace synthetically)
• left subclavian flap angioplasty (transect subclavian artery and use flat to enlarge/repair the aorta)
• balloon angioplasty (introduce a catheter with deflated balloon, inflate to enlarge the narrowed aorta, then remove)