Mitral Regurgitation

Question 1

Symptoms

Answer 1

• symptoms of heart failure
• symptoms of AF
• angina if ischaemic MR
• fever etc if IE as complication

Question 2

Signs

Answer 2

• sternotomy (paravalvular MR in malfunctioning prosthetic valve
• if also vein harvesting scars then could suggest CABG as part of ischaemic MR
• lateral thoracotomy - (MR as part of mixed MV disease or complication of surgical valvotomy
• features of marfans or other CT disorder (mitral prolapse)
• stigmata of endocarditis
• bruising for anticoagulation (valve replacement or AF)
• pulse regular or irregular
• rapid jerky pulse upstroke due to short LV ejection time
• JVP raised in HF or systolic CV waves with 2ry TR
• Apex - May be visible, displaced with volume overload, possible apical thrill
• left parasternal heave of RV pressure overload
• LA heave pre-systole if very enlarged left atrium (more likely to be in AF by this stage)
• palpable P2 if pulmonary HTN

Auscultation

• Soft S1 (if loud or preserves consider prolapse or mixed rheumatic MV disease)
• high-pitched pan-systolic murmur loudest at apex and radiating to axilla. Increasing in intensity with expiration
• widely split S2 esp with severe MR. (A2 earlier due to quicker ejection time of LV
• S3 due to early rapid filling of LV from engorged LA
• S4 due to atrial contraction against a a less compliant, dilated LV (rare as normally AF by now)
• diastolic rumble (rare - occurs as result of high flow in severe MR. Differentiated from MS by soft S1 and absence of an OS

If MR due to mitral prolapse

• normal intensity S1
• single or multiple mid-systolic clicks
• soft high-pitched mid to late systolic murmur
• normal S2 but may develop S3, S4 and loud P2 with increasing severity

Question 3

Tips for mitral prolapse

Answer 3

Anything that makes the heart smaller will allow the leaflets to prolapse further due to the fixed length of chordae tendinae.

• squatting causes increased preload by increasing venous return which makes the heart larger. Also afterload is increased as femoral vessels are clamped, also increasing heart size (due to increased end-systolic volume). So the murmur is quieter and later in systole.
• as the patient stands, venous return and afterload reduces, causing the heart to be smaller and therefore longer, louder and earlier in systole

Question 4

Severity

Answer 4

Severe chronic MR
1. AF
2. Displaced volume overloaded thrusting apex beat 
3. Signs of pulmonary hypertension
4. Signs of cardiac failure
Mild has none of the above features
Moderate has a mix

Question 5

Aetiology

Answer 5

1. Degenerative
2. Functional (2ry to LV dilatation and the causes of this)
3. Ischaemic
4. MV prolapse (1-2.5% of population)
   - hereditary
   - idiopathic
   - marfans and other CT diseases
5. Rheumatic

Question 6

Common pitfalls

Answer 6

1. Don’t confuse mid-systolic click with 2nd HS (otherwise could thinks it’s early diastolic murmur when actually mitral prolapse). Avoid this by timing with central pulse. Can also use dynamic manoeuvres and appreciate high pitch
2. Missing loud S1 which could be only clue of mixed MV disease
3. Incorrectly attributing PSM of TR to radiation from MR or entirely to MR when not present. Distinguish by noting TR murmur oldest during inspiration (carvalho’s sign)

Question 7

Investigations

Answer 7

1. ECG - p-mitrale or AF
2. CXR - congestion or cardiomegaly
3. TTE - to assess severity, mechanism (including leaflet anatomy), LV function and dimensions, pulmonary pressures, RV function.
4. TOE or 3D TOE - to definitively assess severity, mechanism, feasibility of repair and exclude endocarditis
5. As part of pre-operative assessment
   - right and left heart catheterisation (assess pulmonary pressures and coronary anatomy)
   - carotid Doppler
   - orthopentomogram ( to see if dental extractions required before suregery to reduce chance of prosthetic valve endocarditis)

Question 8

Indications for surgery

Answer 8

(No medical treatments known to alter prognosis)

• mild or moderate MR should have annual review with echo
• MV repair surgery or failing this, replacement recommended for:
  1. Asymptomatic patients with EF 30-60% and ESLV dimensions >40mm
  2. Chronic severe MR and new onset AF or PASP >50 even with EF >60%
  3. Severely dilated and impaired LV (EF<30, ESLV >55mm) only if chordal preservationwith durable repair is likely in absence of serious comorbidity and provided medical therapy is optimal
  4. Asymptomatic patients with chronic severe MR and EF >69% and ESLV <40 should be followed up 6 monthly with annual echo

Question 9

Why is MV repair preferable to replacement?

Answer 9

Disconnection of the paravalvular apparatus can result in up to 20% reduction in LV function. So MV replacement without chordal preservation should be avoided when possible.

Question 10

How is ischaemic MR managed differently?

Answer 10

• prognosis of functional ischaemic MR (leaflets normal but movement restricted due to ischaemic injury etc) is worse than organic MR
• the threshold for treatment and definitions of severity are lower. (Severe functional MR is regurgitant orifice of >20mm or regurgitant volume >30ml
• surgery should be considered if undergoing CABG or if (not not undergoing CABG but) EF>30% and symptomatic despite optical medical treatment

Question 11

Are prophylacti abx necessary for dental surgery?

Answer 11

Endocarditis prophylaxis is no longer recommended for uncomplicated MR and MV prolapse