My DDU point form notes on mitral stenosis…
- ASSESSMENT
- CAUSES
- rheumatic disease
- mitral annular calcification (MAC)
- D/DX
- QUANTITATION
- mean transmitral gradient
- VALVE AREA
- planimetry
- pressure half time valve area
- continuity equation
- other
- CONSEQUENCES
- left atrial enlargement / thrombosis
- pulmonary hypertension
- mitral regurgitation
- rheumatic heart disease of other structures
- LV response
- SPECIFIC PATIENT POPULATIONS
- pre commisurotomy
- post commisurotomy
The rest of my DDU notes are here.
ASSESSMENT
anatomy, mobility, calcification
mean transmitral gradient
valve area by
planimetry 2D/3D
pressure half time
pulmonary artery pressures
MR
TTE good
TOE better
except subvalvular
3D useful
degree and asymmetry of commissural fusion
planimetry
CAUSES
rheumatic disease
commonest cause by far
tips affected most
(cf MAC)
bowing / doming due to commissural fusion → tips restricted > base and mid
tip thickening ± base and mid
commonly also affects subvalvular apparatus
chordal shortening, fusion, fibrosis, Ca2+
assessment
leaflet
thickening
Ca2+
mobility
subvalvular involvement
mitral annular calcification (MAC)
commonly found in elderly
is a CV risk factor
LV side of posterior annulus → entire posterior annulus ± AMVL (especially if calcific AS)
can cause mild-moderate MR
occasionally, extends onto base of leaflet → functional MS
D/DX
other causes of pulmonary congestion
LV systolic / diastolic dysfunction
AV disease
MR
rarities
myxoma
cor triatrium
QUANTITATION
Normal | Mild | Moderate | Severe | |
---|---|---|---|---|
Pressure half time (ms) | 40-70 | 71-139 | 140-219 | >219 |
UL 1 x 70 | UL 2 x 70 | UL 3 x 70 + 10 | ||
Mean pressure drop (mmHg) | <5 | 5-10 | >10 | |
Valve area (cm2) | 4-6 | 1.6-2.0 | 1.0-1.5 | <1 |
~same as AS | same as AS | same as AS |
mean transmitral gradient
uses CWD VTI → simplified Bernoulli averaged over curve
if PWD used will underestimate if not placed at narrowest area of flow
depends on transmitral volume flow rate as well as area
∴ if SV down (e.g. due to LV diastolic problems) → relatively low mean gradient
also, with tachycardia and significant MR, gradient can ↑ without MS → in this case deceleration slope of early diastolic filling will not be ↓ (cf MS)
VALVE AREA
planimetry
orifice elliptical, more planar than AS ∴ planimetry useful
validated cf catheter determined valve area, area at surgery
approach
PSAX + zoom
funnel shaped inflow ∴ start mid-pap in PSAX, tilt slowly slightly medially and superiorly until entire orifice just visible
use the highest possible transducer frequency
optimise gain, dynamic range and focus so the
mitral orifice is clearly delineated
use mid-diastolic frame
inner margins of the leaflets at the blood-tissue interface
average 3-5 beats
ideally consecutive, avoid post ectopic beats
3D more reproducible (align image in plane of minimal orifice)
pressure half time valve area
assumptions
assumes rate of pressure decline relates to CSA orifice
neglects LAP, LV compliance issues
PHT
time to halve from max early diastolic pressure gradient
defined invasively initially
for an individual, independent of exercise induced Δ flow rate
Doppler equivalent: time from Vmax to Vmax / √2
empirically: MVA = 220 / PHT
correlates with invasive valve areas
technical considerations
parallel
CFD helpful to align
PWD or CWD
Bonita seems to use CWD
PWD “better definition of maximum velocity and early diastolic slope” per Otto
fails if
arrhythmias
average multiple beats, exclude v short early diastolic periods (can’t measure slope accurately due to next beat / A wave)
non-linear or curvilinear diastolic slopes
if can’t get a linear slope, use mid-diastolic slope
acute changes in LA compliance, LV diastolic dysfunction
∴ not true for 72 hrs post balloon commisurotomy
significant aortic regurgitation (severe)
fills LV → ↓ PHT
can cause functional MS (Austin-Flint) → ↑ PHT
atrial shunt
continuity equation
MVA = transmitral SV / VTIMS jet
VTIMS jet from CWD
SV from
CSALVOT x VTILVOT (if no MR or AR)
CSAPA x VTIPA
only accurate if
no significant MR, AR if using LVOT to get SV
parallel VTIMS jet
useful with Δ chamber compliance
other
PISA not used – doesn’t work due to need to integrate volume flow rate over diastolic filling period
CONSEQUENCES
left atrial enlargement / thrombosis
pressure → enlargement
enlargement + low volume flow rate due to MS → stasis → thrombus
thrombi in LAA > on wall, IAS (laminated)
more common in AF
TTE <50% sensitive
can’t see LAA well
best views
PSAX @ aortic valve + lateral angulation
A2C + superior tilt
beamwidth artefact / poor penetration contribute
TOE 99% specific and sensitive
high frequency (5-7MHz)
closer
pulmonary hypertension
MS → ↑ LAP → pulmonary venous HT → arterial HT
initial passive ↑ pulmonary arterial pressures (PVR unΔ)
reversible
later Δ vascular bed → ↑ PVR
exercise testing if symptoms > expected for degree of MS
measure immediately post exercise
mitral regurgitation
common
significant → CI to commisurotomy
PHT valve area and planimetry still accurate, continuity not accuate
rheumatic heart disease of other structures
aortic valve
AR and MS jets together can complicate assessment of AR
assess just proximal to AV (in LVOT) to avoid problems
tricuspid valve
TS hard to see on 2D
Doppler useful
assess TR carefully – may need annuloplasty at time of MV surgery
LV response
usually LV is small
dilated → look for MR, AR, IHD etc
diastolic function impaired due to small orifice
SPECIFIC PATIENT POPULATIONS
pre commisurotomy
scoring systems predict haemodynamic results and complications
leaflet mobility, thickness, Ca2+
commissural Ca2+
subvalvular involvement
CI if moderate or worse MR
LA thrombus
may be dislodged by procedure
post commisurotomy
MR
ASD size @ transeptal puncture site
PHT valve area method inaccurate
PASP
from BSE except where noted
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Tags: DDU DDU Notes mitral stenosis