Aortic Stenosis

Knowledge Check

Exam-style MCQs aligned with these notes. Available to Hyperexcision Scholar members.

Last updated: April 12, 2026Bookmark

Aortic stenosis is the narrowing of the aortic orifice due to atherosclerosis, calcification, or fibrosis. It leads to left ventricular outflow tract obstruction, which can progress to left ventricular failure.

It peaks at 70+ years, and affects men and women equally.

Causes
- Age-related degenerative calcification
- Bicuspid aortic valve
  - This predisposes to early calcification and stenosis
- Rheumatic heart disease
  - Leads to a mixed aortic valve disease (stenosis and regurgitation)
- Unicuspid and quadricuspid aortic valve
- Williams syndrome
- Exposure to chest radiation
- Familial hypercholesterolaemia
Patient history
- Elderly patient with chest pain, exertional dyspnoea, or syncope
- Classical triad of angina, syncope, and heart failure
Pathophysiology
- Valve leaflet calcification and fibrosis → decreased valve area → pressure overload on the left ventricle → left ventricular hypertrophy → diastolic dysfunction
- Hypertrophic left ventricle and decreased aortic valve area → reduced coronary perfusion → ischaemia
- Diastolic dysfunction and ischaemia → left ventricular failure
Signs and symptoms
- Exertional dyspnoea
  - Reduced exercise tolerance
  - Easy fatiguability
- Exertional angina
- Exertional syncope or presyncope
- Signs of heart failure
Physical examination
- Loud mid-to-late paking systolic ejection murmur
  - Early peaking is associated with mild to moderate stenosis
  - Late peaking is associated with severe stenosis
  - Radiates to the carotids
  - More prominent with sitting forward and in expiration
  - Becomes softer the more severe the stenosis
  - May radiate to the apex and have a musical quality (Gallavardin phenomenon)
- Slow-rising and low-volume carotid pulse (pulsus parvus et tardus)
- Soft or absent S2
- Narrow pulse pressure
- Reverse splitting of S2
- Heaving apex beat
- Systolic thrill
- S4
Differentials
- Coronary artery disease
- Heart failure
- Cardiac arrhythmia
- Aortic sclerosis
- Mitral regurgitation
- Hypertrophic cardiomyopathy
Investigations
- Electrocardiogram
  - Atrial fibrillation
  - Left ventricular hypertrophy with a strain pattern
  - P-mitrale
  - Left axis deviation
  - Poor R-wave progression
  - LBBB or complete atrioventricular block (due to calcified ring)
- Chest X-ray
  - Left ventricular hypertrophy
  - Calcified aortic valve
  - Post-stenotic dilatation of the ascending aorta
- Transthoracic Echocardiogram for diagnosis
  - Peak gradient
  - Valve area
  - Aortic jet velocity
- Exercise stress testing or Dobutamine stress echocardiogram
- B-type natriuretic peptide to assess for heart failure
- Multi-slice CT to determine the extent of calcification
- Cardiac MRI to quantify myocardial fibrosis
- Cardiac catheterization, if non-invasive tests are non-diagnostic
Treatment
- Regular follow-up
- Treat heart failure
- Maintain sinus rhythm
- Control hypertension
- Surgical aortic valve replacement (SAVR)
- Transcatheter aortic valve implantation (TAVI)
- Percutaneous balloon valvotomy
  - Palliative care for patients who are not suitable for cardiac surgery, or in children with congenital aortic stenosis
Complications
- Heart failure
- Sudden cardiac death
- Arrhythmias
  - Atrial fibrillation
  - Ventricular arrhythmias
- Gastrointestinal bleeding
  - Heyde’s syndrome – aortic stenosis, anaemia due to bleeding, and acquired coagulopathy
  - Von Willebrand multimers are broken as they pass through the narrow aortic valve
- Endocarditis

Reference Intervals ›

Biochemistry

ACTH	P: <80 ng/L
ALT	P: 5–35 U/L
Albumin	P: 35–50 g/L
Aldosterone	P: 100–500 pmol/L
Alk. phosphatase	P: 30–130 U/L
α-Amylase	P: 0–180 IU/dL
α-Fetoprotein	S: <10 kU/L
Angiotensin II	P: 5–35 pmol/L
ADH	P: 0.9–4.6 pmol/L
AST	P: 5–35 U/L
Bicarbonate	P: 24–30 mmol/L
Bilirubin	P: 3–17 μmol/L
BNP	P: <50 ng/L
CRP	P: <10 mg/L
Calcitonin	P: <0.1 mcg/L
Calcium (ionized)	P: 1.0–1.25 mmol/L
Calcium (total)	P: 2.12–2.60 mmol/L
Chloride	P: 95–105 mmol/L
Cholesterol	P: <5.0 mmol/L
VLDL	P: 0.128–0.645 mmol/L
LDL	P: <2.0 mmol/L
HDL	P: 0.9–1.93 mmol/L
Cortisol AM	P: 450–700 nmol/L
Cortisol Midnight	P: 80–280 nmol/L
CK ♂	P: 25–195 U/L
CK ♀	P: 25–170 U/L
Creatinine	P: 70–100 μmol/L
Ferritin	P: 12–200 mcg/L
Folate	S: 2.1 mcg/L
FSH	P: 2–8 U/L ♂; >25 menopause
GGT ♂	P: 11–51 U/L
GGT ♀	P: 7–33 U/L
Glucose (fasting)	P: 3.5–5.5 mmol/L
Growth hormone	P: <20 mu/L
HbA1C (DCCT)	B: 4–6%
HbA1C (IFCC)	B: 20–42 mmol/mol
Iron ♂	S: 14–31 μmol/L
Iron ♀	S: 11–30 μmol/L
Lactate (venous)	P: 0.6–2.4 mmol/L
Lactate (arterial)	P: 0.6–1.8 mmol/L
LDH	P: 70–250 U/L
LH	P: 3–16 U/L
Magnesium	P: 0.75–1.05 mmol/L
Osmolality	P: 278–305 mosmol/kg
PTH	P: 0.8–8.5 pmol/L
Potassium	P: 3.5–5.3 mmol/L
Prolactin ♂	P: <450 U/L
Prolactin ♀	P: <600 U/L
PSA	P: 0–4 mcg/mL
Protein (total)	P: 60–80 g/L
Red cell folate	B: 0.36–1.44 μmol/L
Renin (erect)	P: 2.8–4.5 pmol/mL/h
Renin (recumbent)	P: 1.1–2.7 pmol/mL/h
Sodium	P: 135–145 mmol/L
TBG	P: 7–17 mg/L
TSH	P: 0.5–4.2 mU/L
T4	P: 70–140 nmol/L
Free T4	P: 9–22 pmol/L
TIBC	S: 54–75 μmol/L
Triglycerides	P: 0.50–2.3 mmol/L
T3	P: 1.2–3.0 nmol/L
Troponin T	P: <0.1 mcg/L
Urate ♂	P: 210–480 μmol/L
Urate ♀	P: 150–390 μmol/L
Urea	P: 2.5–6.7 mmol/L
Vitamin B12	S: 0.13–0.68 nmol/L
Vitamin D	S: 50 nmol/L

Arterial Blood Gases

pH	7.35–7.45
PaCO₂	4.7–6.0 kPa
PaO₂	>10.6 kPa
Base excess	±2 mmol/L

Urine

Cortisol (free)	<280 nmol/24h
Hydroxyindole acetic acid	16–73 μmol/24h
Hydroxymethylmandelic acid	16–48 μmol/24h
Metanephrines	0.03–0.69 μmol/mmol cr.
Osmolality	350–1000 mosmol/kg
17-Oxogenic steroids ♂	28–30 μmol/24h
17-Oxogenic steroids ♀	21–66 μmol/24h
17-Oxosteroids ♂	17–76 μmol/24h
17-Oxosteroids ♀	14–59 μmol/24h
Phosphate (inorganic)	15–50 mmol/24h
Potassium	14–120 mmol/24h
Protein	<150 mg/24h
Protein/creatinine ratio	<3 mg/mmol
Sodium	100–250 mmol/24h

Haematology

WCC	4.0–11.0 ×10⁹/L
RBC ♂	4.5–6.5 ×10¹²/L
RBC ♀	3.9–5.6 ×10¹²/L
Hb ♂	130–180 g/L
Hb ♀	115–160 g/L
PCV ♂	0.4–0.54 L/L
PCV ♀	0.37–0.47 L/L
MCV	76–96 fL
MCH	27–32 pg
MCHC	300–360 g/L
RDW	11.6–14.6%
Neutrophils	2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes	1.0–4.5 ×10⁹/L (20–45%)
Eosinophils	0.04–0.44 ×10⁹/L (1–6%)
Basophils	0–0.10 ×10⁹/L (0–1%)
Monocytes	0.2–0.8 ×10⁹/L (2–10%)
Platelets	150–400 ×10⁹/L
Reticulocytes	0.8–2.0% / 25–100 ×10⁹/L
Prothrombin time	10–14 s
APTT	35–45 s

Paediatric

Pulse Rate (bpm)
Neonate	140–160
Infant <1yr	120–140
1–5 years	110–130
5–12 years	80–120
>12 years	70–100
Respiratory Rate (tachypnoea)
0–2 months	≥60/min
2–12 months	≥50/min
1–5 years	≥40/min
>5 years	≥30/min
Blood Pressure (mmHg)
Term	65/45
1 year	75/50
4 years	85/60
8 years	95/65
10 years	100/70
Weight Formulas
3–12 months	(a + 9)/2 kg
1–6 years	2a + 8 kg
>6 years	(7a − 5)/2 kg
Haemoglobin (g/dL)
Term newborn	13–20
1 month	11–18
2 months	10–15
1–2 years	10–13
>2 years	11–14
MUAC (6 months–5 years)
Obese	>17.5 cm
Normal	13.5–17.4 cm
At risk	12.5–13.4 cm
Moderate malnutrition	11.5–12.4 cm
Severe malnutrition	<11.5 cm
Developmental Milestones
Social smile	1.5 months
Head control	4 months
Sits unsupported	7 months
Crawls	10 months
Stands unsupported	10–12 months
Walks	12–13 months
Talks	18 months
CSF WBC (/mm³)
Term newborn	0–25
>2 weeks	0–5

Calculator ›

Leave a ReplyCancel Reply