Mitral Regurge Flashcards
(40 cards)
What are the 4 grading severities of MR?
- Trivial
- Mild
- Moderate
- Severe
What are the components of assessing MR?
Jet Area (small, variable, large)
Flow Convergence (small, inter, large)
Regurge Vol (ml/beat) (<30,30-60, >60)
Regurge Fraction (<30, 30-50, >50)
Pulmonary Vein (normal, blunt, reverse)
Vena Contracta Width (mm) (<3, 4-7, >7)
EROA - PISA (cm2) (<0.2, 0.2-0.4, >0.4)
What is the Vena Contracta? What are the steps of measuring the Vena Contracta of MR?
The narrowest part of the regurgitant jet as it passes back through the valve
Can be measured on Central or Single Eccentric Jets
- Measured in LAX (perpendicular to the coaptation line)
- Increase the depth to the mitral leaflets
- Colour Box on Origin of Jet
- Set Niqust between 40-70cm/s
- Measure the widest jet (average 3 measurements) [cannot be preformed if multiple jets]
How is the VC influenced by loading in comparison to jet area and jet length?
It is less influenced by loaded
Can you measure Vena Contracta Area? What are the benefits
Yes, using MPR analysis of 3D datasets
Can then calculate the EROA
Benefits:
- no assumption made about the shape of the regurge orifice
- can be used if multiple jets
41mm2 = moderate to severe MR
How is the MR Jet Area quantified?
To the LA Area
if < 20% LA Area = mild
if >40% LA Area = severe
What is an advantage of using Regurge Jet Area?
It is not affected by loading conditions , ventricular function, atrial size compliance or Doppler gain settings
For the same Severity of Regurge:
acute MR, small LA, small jet
chronic MR, larger LA, larger jet
What is a dis-advantage of using Regurge Jet Area?
It cannot be used for eccentric jets
jet area underestimates the severity of eccentric jets due to the choanda effect
Therefore, all wall-hugging jets should be considered severe
Jet Area»_space; Jet Length
On what assumption is Flow Convergence/PISA based?
Blood flow at a point of colour aliasing proximal to the valve is the same as blood flow through the regurge orifice
Discuss the process of PISA measurement to find the EROA
- colour doppler at LV side of the valve
- locate the point where the blood velocity > nquist limit (this is identified by aliasing)
the zone of colour aliasing = a hemisphere of constant known velocity (ie. the Niqust Limit) - the “PISA”
- decrease the NL to 40cm/s (this helps display a well defined PISA hemisphere) [need an accurate PISA measurement as the radius value will be squared]
if you underestimate PISA = underesimate EROA
Write out the Continuity Eqn using PISA to find EROA
Flow at PISA = Flow through Valve
(Flow = Velocity x CSA)
Vpisa x CSApisa = Vorifice x EROA
NL x 2πr-2 = Peak MR Jet Velocity x EROA
EROA = NL x 2πr-2/ V mr
EROA < 0.2cm-2 = mild MR
EROA 0.2 - 0.4cm-2 =-2.2 cm moderate MR
EROA >0.4cm-2 = severe MR
How do you calculate the Regurge Volume?
Regurge Volume = EROA mr x VTI mr
> 60ml = severe MR
For what type of MR Jets is PISA suited? and to what other MR measurement is it similar to?
- more accurate for central rather than eccentric jets
- similar to measuring VC width (as it also assumes a circular regurge orifice)
Why is the Nquist Limit set to 40cm/s when measuring PISA?
This reduces the original equation from
EROA = NL x 2πr-2/ V mr
r2/2
if PISA radius = 1.0cm -> EROA 0.5cm2
so if PISA radius > 1.0cm -> Severe MR
[assuming the LA/LV pressure difference > 100 mmHg……. ie. Vmr 5m/s]
*not when LV function decreased as the LV:LA pressure difference < 100mmHg)
How does MR affect the Pulmonary Venous Flow?
Alter pulmonary venous PW Doppler
Moderate MR: Systolic Blunting (S<D)
Severe MR: Systolic Flow Reversal
What pathologies can cause S wave blunting in Pulmonary Venous Doppler flow?
anything that increases LA pressure:
-MR
- MS
- LV Diastolic Dysfunction
What considerations must be taken into account when assessing MR Severity?
- Haemodynamic State of the Patient
(esp in Secondary MR)
Severity will be decreased when BP decreases (preload, contractility, afterload)
- Variations in the Cardiac Cycle
i) degenerative disease -> increased severity in systole (peaks before the end of systole)
ii) secondary MR = greatest in early systole
iii) AFib - beat-to-beat variations in SV (average)
- Type of Orifice
Vena Contracta/PISA assume a circular orifice
- applicable to segmental prolapse/flail
- not applicable to Secondary MR or Rheumatic MR (often slit-like orifice so will underestimate the severity)
VC doesn’t underestimate for elliptical jets (so good for secondary MR)
When assessing a Secondary MR - what should you be mindful of?
Secondary MR is highly influenced by loading conditions (underestimated by VC/PISA)
If Secondary MR EROA >0.2cm-2 (by PISA) - this is an independent predictor of cardiac death
How does GA affect the severity of MR?
decreases it, as GA will decrease the preload and afterload
it will underestimate the regurge (so don’t go against the pre-op TTE)
What are the four main questions when you begin to look at MR?
- Severity?
- Mechanism?
- Location?
- Repairable?
What are the main causes of mitral regurge?
- Myxomatous Degeneration (developed world)
- Rheumatic Heart Disease (developing world)
- Ischaemia (causing pap muscle dysfunction/rupture)
- Cardiomyopathy (dilation/ IHSS)
- Endocarditis
- Congential (cleft anterior leaflet with AV …. defect)
- CT Disease (Marfan’s, SLE, RA)
What are the 3 types of MV Leaflet Motion as per Carpentier?
Type 1: normal
Type 2: excessive (away from dx leaflet)
Type 3: restrictive (towards dx leaflet)
What are the causes of Carpentier 1 MV?
Type 1: Normal
- hole in leaflet
- annular dilation/malcoaptation
What are the causes of Carpentier 2 MV?
Type 2: Excessive Motion
(away from the diseased leaflet)
- billowing
- prolapse
- flail
