6.2 MTB Step 3 - Valvular Heart Disease (Aortic Stenosis)

Question 1

AORTIC STENOSIS (AS)

What are (5) Common Clinical Presentations of AS?

Answer 1

1. Older Patient w/ hx of HTN
2. CHEST PAIN (most common)
3. CAD (in upto 50% of patients)
4. Syncope
5. CHF

Question 2

AORTIC STENOSIS (AS)

What is the Prognosis in the following (3) types of patients with AS?

1. AS + CAD
2. AS + Syncope
3. AS + CHF

Answer 2

1. AS + CAD = 3 - 5 year average survival
2. AS + Syncope = 2 - 3 year average survival
3. AS + CHF = 1.5 - 2 year average survival

Question 3

AORTIC STENOSIS (AS)

What is the Mechanism of Syncope/Angina in AS?

Answer 3

A stiff valve just proximal to the entry point of coronaries blocks blood flow into the vertebral and basilar arteries and carotids:

• No Flow to Brain = Passing out.
• Thus, AS causes LV Hypertrophy.
• LV Hypertrophy = Increased Demand
• AS = Blocked Flow with Increased Demand = Chest Pain

Question 4

AORTIC STENOSIS (AS)

What Type of Murmur does AS give?

Answer 4

Crescendo-Decrescendo Systolic Murmur

Question 5

AORTIC STENOSIS (AS)

What is the Mechanism of Crescendo/Decrescendo Murmur of AS?

Answer 5

The first part of the Cardiac Cycle is Isovolumetric contraction:

• With Isovolumetric contraction, no blood moves.
• No blood moving = No murmur.
• Peak flow occurs in Mid-Systole.
• Peak Flow = Peak Noise.
• Hence, AS yields a Diamond-shaped Crescendo-Decrescendo murmur.

Question 6

AORTIC STENOSIS (AS)

1. What is the Best INITIAL Test for AS?
2. What is a MORE Accurate Test for AS?
3. What is the Most ACCURATE Test for AS?

Answer 6

1. TTE
2. TEE
3. Left Heart Catheterization - also allows the most accurate method of assessing the Pressure Gradient across the Aortic Valve (normal aortic valve gradient = 0).

Question 7

AORTIC STENOSIS (AS)

1. What is considered Mild AS?
2. What is considered Moderate AS?
3. What is considered Severe AS?

Answer 7

Left Heart Catheterization:

1. Mild AS = gradient < 30 mmHg
2. Moderate AS = gradient 30 - 70 mmHg
3. Severe AS = gradient > 70 mmHg

Question 8

AORTIC STENOSIS (AS)

What is the Best INITIAL Therapy for AS?

Answer 8

Diuretics

• However, they will NOT alter Long-term prognosis
• Further, overdiuresis is Dangerous, and use of diuretics needs to be VERY judicious.

Question 9

AORTIC STENOSIS (AS)

What is the Most Common definitive Treatment for AS?

Answer 9

Valve Replacement Surgery:

• Bioprosthetic Valves (porcine, bovine) last 10 years on average, but do NOT require anticoagulation with Warfarin.
• Mechanical Valves last 15 - 20 years on average, but MUST be treated with Warfarin to an INR = 2 - 3.

Valve replacement is well tolerated, even in the elderly.

Answer for “Which procedure has a Higher Risk of AKI and A-Fib?” = SURGERY

Question 10

AORTIC STENOSIS (AS)

What is considered an Acceptable Alternative to the Most Common definitive Treatment for AS?

Answer 10

Transcatheter Aortic Valve Replacement (TAVR)

• Valve Replacement deployed through a catheter.
• Slightly lower risk of death compared with surgery.
• NOT an option for Regurgitant Lesions (i.e., AR, MR)
• Answer* *for “Which procedure has a Higher Risk of Residual Aortic Regurgitation and Need for Pacemaker Placement?” = TAVR