Heart Valve Disease Flashcards
Aetiology of Aortic stenosis
- Vast majority due to ‘Degenerative’ calcific stenosis with tricuspid valve intervention in eight decade (elderly: 65+ 45% population)
- Bicuspid valves are a cause of earlier degeneration (5-6th decade)
- Less common causes include rheumatic disease (accompanied by mitral valve disease, 30-60), radiotherapy (fibrosis), congenital stenosis, William’s syndrome (supravalvular AS)
Pathophysiology of AS
-Progressive restriction of leaflets leads to Valvular obstruction resulting in:
=Hypertrophy and then fibrosis of the left ventricle due to pressure overload
=Inability to augment cardiac output
- Initial insult to endothelium of A valve
- Lipid and inflammatory cell infiltration (analogous to atherosclerosis)
- Fibrosis and calcification (progressive once established)
-Aortic stenosis causes ventricular pressure overload eventually leading to left ventricular dysfunction if untreated
Symptoms of AS
- In general symptoms don’t appear until stenosis is severe
- Angina, often in the absence of obstructive coronary disease (ventricle hypertrophy= oxygen demand supply)
- Exertional syncope (diverted blood to muscles and vasodilatation requires increase in CO, cardiac decompensation)
- Dyspnoea (left atrium and pulmonary veins increase= heart failure)
=CHEST PAIN, SYNCOPE, BREATHLESSNESS
Clinical signs AS
- Ejection systolic murmur (crescendo decrescendo)
- Quiet/ absent second heart sound (ejection of blood more prolonged when worsening, movement reduced so not closing with as much energy)
- Radiation to carotids
- Slow-rising pulse (restricted outflow= prolonged ejection and low volume)
- Forceful but not displaced (volume overloaded) apex beat (hypertrophy so pressure overloaded)
Severe:
=Narrow pulse pressure, slow rising pulse, delayed ESM, soft/absent S2, S4, thrill, duration of murmur, LVH
Treatment of AS
-AS needs treatment when it is severe and:
=Patient has symptoms
OR
=LV function is deteriorating
-Medical treatment is not effective (mechanical problem): diuretics for HF
-Surgical aortic valve replacement (bioprosthetic can deteriorate/ mechanical)
=If asymptomatic but valvular gradient >40mmHg and features of LVSD consider surgery
-TAVI (trans-catheter valve implants) for those not eligible/ high risk- balloon expandable, durability? Balloon valvuloplasty in children with no aortic valve calcification
-Assessment of symptoms and left ventricular function is critical to follow-up of patients with AS
Prognosis of AS
- Prognosis of aortic stenosis even when severe is good when asymptomatic
- Once symptoms appear prognosis dramatically worsens
Long-term care of AS
- Valve replacement improves symptoms in the vast majority of patients and returns them to a near-normal life expectancy although has some risks
- The goal of management is to intervene before irreversible myocardial damage without exposing asymptomatic patients to risks of AVR too early
- Timely surgical or trans-catheter treatment of AS can return prognosis to near-normal
Risks of valve replacement AS
- Operative: death (~1-3%) , Stroke, PPM (pacemaker)
- Long-term: Endocarditis (~0.5%/ year), Thrombo-embolism, Bleeding with anticoagulation (mechanical AVR), valve degeneration bioprosthetic)
Investigations of AS
- ECG= large complexes, strain pattern (T wave inversion in 5 and 6)= left ventricular hypertrophy
- Echo= leaflets thickened and calcified, hypertrophied LV
- Doppler= speed of blow flow across valve= faster velocity
- Transthoracic Echo= trace valve
- CT= heavy calcification, volume of calcium
Aetiology and pathophysiology of Primary MR
-Primary= related the valve itself between left atrium and ventricle, anterior and posterior leaflets)
=Degenerative (most common, includes myxomatous disease and mitral valve prolapse)
=Rheumatic heart disease (with MS)
=Infective endocarditis (leaflet perforation or caudal rupture)
=Acute myocardial infarction (papillary muscle rupture, rare, urgent surgery)
RF: female, lower BMI, age, renal dysfunction, prior MI, collagen
Aetiology and pathophysiology of Secondary MR
-Secondary= caused by dysfunction of the surrounding structure
=Left ventricular dysfunction/ cardiomyopathy (distortion of the sub-valvular apparatus)
Symptoms of MR
- Usually asymptomatic (left atrium compliance increases, LV dilatation for volume overload)
- Dyspnoea – mainly on exertion (heart failure)
- Orthopnoea / paroxysmal nocturnal dyspnoea
- Fatigue
- Palpitations (if the patient goes into AF)
- Swelling of ankles/ pitting oedema
Clinical signs of MR
- May find an irregular pulse (AF)
- Blood pressure and pulse pressure are usually normal
- Hyperdynamic displaced apex beat laterally
- Pansystolic murmur – heard loudest at the apex, usually radiating to the axilla (depending on anterior or posterior leaflet affected), blowing, S1 quiet widely split S2
- Signs of congestive heart failure may be present (elevated JVP, lung crepitations, pitting edema in lower limbs)
Investigations of MR
-Echocardiogram (single most useful test)
=Useful to diagnose MR, assess cause and severity of MR
=Also useful to assess LV size/function and assess for pulmonary hypertension
=Transthoracic echo is suitable for most cases
=Transoesophageal echo may be needed for patients with severe MR being considered for intervention
-ECG
=May see atrial fibrillation or a broad notched p wave
-Chest X-ray
=May see cardiomegaly and/or signs of congestive heart failure
Treatment of severe chronic primary MR
-Ongoing medical therapy with close follow-up (HF and AF)
-Mitral valve repair/replacement
-Transcatheter mitral valve intervention (Mitraclip)
=May be considered in patients with high surgical risk