Pathophysiology of aortic stenosis?

Spoiler

Lipid accumulation in the valve → fibrosis, calcification and stiffening → stenosis

What are the symptoms of AS?

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In mild AS
• Asymptomatic
In moderate cases
• Angina
• Syncopal attacks
• Dyspnoea
In severe cases
• Complications: pericarditis & MI
• Sudden death

Triad of aortic stenosis?

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• Syncope
• Anginal pain
• Dyspnoea

What are the complications you may expect?

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• LVH
• VF
• Ventricular tachycardia (VT)
• CHF
• HTN
• Angina
• Intra operative sudden death

Explain syncope in AS?

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Occurs upon exertion when systemic vasodilatation in the presence of a fixed stroke volume and COP causes the arterial systolic blood pressure to decline.

What intraoperative complications can lead to death?

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• Myocardial infarction
• Aortic dissection

What are the anaesthetic considerations?

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Patient will have fixed cardiac output cannot respond to decreased afterload.

What preoperative investigation to do?

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• Transthoracic echocardiography / Transoesophageal echo
• Chest x ray
• ECG

What is the finding in ECG?

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Left ventricular hypertrophy

Why/Explain your finding in the previous answer?

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S wave in V2 + R wave in V6 = more than 35 small squares.
T wave inversion and altered ST segment in V2 to V6.
ECG changes in Aortic stenosis?
Left axis deviation
LVH
Heart block
ST segment change

How to calculate HR based on this ECG?

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300 / number of large squares between two R‑R intervals

What are the advantages and disadvantages of doing AS surgery first VS doing bladder cancer surgery first?

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Doing AS first → reduces risk of complications but increases risk of cancer spread
Doing cancer surgery first → prevents spread of cancer but increases risk of AS complications and death

What to do first, AS or bladder cancer surgery?

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Depends on severity of aortic stenosis
Normal aortic valve surface area: 2.5–3.5 cm²
If aortic valve surface area < 1 cm² → severe stenosis → do AS surgery first

What is antibiotics prophylaxis?

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NICE guidelines: No antibiotics except for major procedures or highly infected procedures (e.g., lower and upper GI surgeries)

What are types of valve in valvular replacement surgery?

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Tissue valve
Mechanical valve

What are the differences between them? Mention 3

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-Mechanical
Made of metal / ceramic
Warfarin for life
Higher thrombo‑embolism & bleeding risk
Excellent durability (>95% at 10 years), can last lifetime
Slight clicking noise
-Tissue Valve
Made of animal / human tissue
No warfarin needed (only first 3 months)
Lower thrombo‑embolism & bleeding risk
Wear out after 10–20 years
Noiseless

What is the non‑surgical option for valvular replacement?

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Transcatheter aortic valve replacement
Right aortic balloon valvuloplasty

Define aortic sclerosis?

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Valve disease with insignificant gradient across the valve that can progress to stenosis

State a common complication from the use of thiazide diuretics that might result in postponing the surgery?

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Hypokalaemia and hyponatraemia

--Note--
You may be asked about intrinsic and extrinsic pathways
Intrinsic Pathway
Trigger: Internal damage to the blood vessel wall (e.g., plaque rupture).
Initiation: Exposure of negatively charged surfaces such as collagen activates factor XII (Hageman factor).
Cascade: Sequential activation of factors XII, XI, IX, VIII, and X.
Extrinsic Pathway
Trigger: External trauma causing tissue injury.
Initiation: Tissue factor (TF) released from damaged cells activates factor VII.
Cascade: Activated factor VII (VIIa) activates factor X.

Activated factor X (Xa) joins the common pathway

Common Pathway
Convergence: Both intrinsic and extrinsic pathways meet at factor X activation.
Thrombin Formation: Factor Xa + factor V + calcium + phospholipids convert prothrombin → thrombin.
Fibrin Formation: Thrombin converts fibrinogen → fibrin, forming a mesh that stabilises the clot.