Aortic stenosis Flashcards
aortic valve
normal is composed of three thin cusps, projecting from the wall at the origin of the aorta
aortic stenosis (AS) refers to a tight valve
aortic sclerosis is usually considered the precursor of calcified, degenerative AS
sclerosis is more common than stenosis
epidemiology
AS is the most freq type of valvular heart disease in europe and north america
most often presents as calcific AS in adults of advanced age
2-7% of the population aged over 65yo
10% >80yo, with a 50% 2 year mortality unless outflow obstruction is relieved
2nd most common cause, and most common in the younger age group, is congenital
rheumatic AS has become rare in developed countries
risk factors
congenital bicuspid valve predisposes to both regurge and stenosis
presentation
SOB on exertion angina dizziness syncope heart failure of unknown cause (because the murmur may be faint)
the disappearance of the second aortic sound is specific to severe AS, although not a sensitive sign
Sx
may be asymptomatic for many years, but still susceptible to sudden events
only 4% of sudden cardiac deaths in severe AS occur in asymptomatic patients
predisposes to angina, so always auscultate the chest when someone presents with angina
angina presents in 2/3rds of patients with critical AS, of whom 50% have significant coronary artery disease
syncope and even sudden death on exertion
Sx of congenital disease will often present between 10-20yo
chest pain, heart failure and syncope only in 30-40% and usually >50yo
fatigue may be the presentation in children
syncope may be caused by arrhythmia or heart failure and the sudden decline in cardiac output
signs
slow rising, flat character pulse called pulsus parvus et tardus
small pulse pressure (difference between systolic and diastolic) - may be less obvious in the elderly due to rigid aorta
thrills at cardiac apex
LVH
AS murmur
A2 is soft in AS, normal or loud in aortic sclerosis
both are ass. w/ a harsh early systolic murmur, transmitted to the carotids
aortic aneurysm in the proximal aorta may cause a similar murmur. may also cause leakage from the valve and therefore an early diastolic murmur
typical is a crescendo-decrescendo systolic ejection murmur between 1st and 2nd heart sounds
loudest at the base of the heart
most commonly heard in the second right intercostal space
a 4th heart sounds indicates LVH in severe AS
ejection click may be present, esp with bicuspid valves
NB if congestive heart failure leads to a fall in cardiac output then murmur will be quieter
DDx (of murmurs appearing to be from aortic valve)
aortic sclerosis
aortic regurg
subacute bacterial endocarditis
dilation of the root of the aorta (may also lead to leaking valve)
pulmonary valve murmurs in patients with atrial septal defect
investigations
ECG–> LVH or left ventricular strain
CXR may show cardiac enlargement, calcification of the aortic ring. often normal except in advanced disease
echocardiography
key diagnostic tool
confirms AS
assesses:
degree of valve calcification
left ventricular function and wall thickness
other associated valve disease or aortic pathology
consider transoesophageal when transthoracic is of insufficient quality
doppler echo is the preferred technique for assessing AS severity
exercise testing
contraindicated in symptomatic patients with AS
recommended in physically active patients for unmasking Sx
for risk stratification of asymptomatic patients with severe AS
safe in asymptomatic, if performed under supervision of experienced physician monitoring BP, ECG changes and for Sx
multi-slice computerised tomography (MSCT) and cardiac magnetic resonance
provide additional info of the ascending aorta when it is enlarged
medical therapy
progression of AS is an active process
statin therapy not recommended if the only purpose is to slow progression
modification of atheroscelrotic risk factors is highly recommended
digoxin, diuretics, ACE inhibitors if unsuitable for TAVI, or awaiting TAVI if experiencing HF Sx
treat HTN, but carefully monitor to avoid hypotension
use anti-arrhythmic drugs if needed to maintain sinus rhythm (important)
monitoring
stress tests should determine recommended level of physical therapy
echo
reevaluate asymptomatic every 6 months for any change
consider measurement of natriuretic peptides
aortic valve replacement (AVR)
definitive therapy for severe AS
careful weighing f pros and cons if the patient has severe asymptomatic AS
pulmonary autograft replacement (Ross procedure) used in infants and children, use in adults is controversial
