MITRAL VALVE REGURGITATION QUALITATIVE EXAMINATION: EVALUATE MECHANISM OF MR
TYPES AND SOURCE OF MV LEAFLET MOTION •
Normal leaflet motion (type I) (Figure 9.1A) u Mitral annular dilatation (dilated
u Leaflet perforation (endocarditis) u Congenital cleft valve
Excessive leaflet motion (type II) (see Figures 9.1B and C) u Prolapse, billowing, flail u Chordal/papillary muscle elongation (myxomatous, Marfan syndrome) u Chordal/papillary muscle rupture (MI) u Criteria for prolapse: (best viewed in ME LAX) – >2 mm displacement of leaflet above annulus Restrictive leaflet motion (type III) u Restriction in systole and diastole (type IIIa) – Commissural fusion/fibrosis (rheumatic)
Purpose: To evaluate the following: Is valve coaptation preserved? Are leaflets displaced superiorly, above the mitral annulus (prolapse, billowing)? Is leaflet structure disrupted (flail)? Is there systolic anterior leaflet flutter (consider presence of AI)? Are the LV and LA dilated (increased diastolic volume)? Is global LV function preserved (if not, consider mitral annular dilation as cause of MR)?
9 Mitral Valve
2D ME 4 Chamber (0°, 60°, 90°, 120°)
9 Mitral Valve
First order Second order
C Figure 9.1 Examples of normal and excessive leaflet motion. (Sidebotham et al: Practical Perioperative Transesophageal Echocardiography, 2003, Butterworth-Heinemann.)
Mitral annular calcification
Ischemia (ischemic papillary muscle, most often posteromedial)
u Restriction only in systole (type IIIb)
Color Flow Doppler (CFD) Jet direction in LA Direction
Eccentric (in relation to affected leaflet) Away
IDENTIFY THE AFFECTED SEGMENT(S)
Figure 9.2 TG SAX mitral annulus view. (Sidebotham et al: Practical Perioperative Transesophageal Echocardiography, 2003, Butterworth-Heinemann.)
L L P1 A1 A2 A3
A2 A1 P1 R
Figure 9.3 ME 4-chamber view (0°–20°). (Sidebotham et al: Practical Perioperative Transesophageal Echocardiography, 2003, Butterworth-Heinemann.)
Turn right LA P3 P1
Figure 9.4 Commissural view (60°).
LA P3 A3 A2 A1
Figure 9.5 ME 2-chamber view (90°).
Turn left LA P2 A2
Turn right P1
Figure 9.6 ME LAX view (120°).
SEMIQUANTITATIVE EXAM: EVALUATE SEVERITY CFD Spatial Area Mapping (Planimetry of Jet) •
Limitation: color gain, pulse repetition frequency, image density, LA size, LA compliance, LA–LV pressure gradient, hemodynamics, and mitral orifice size and shape; overall poor correlation with
severity; jet area/LA (increase gain until “snow” is present then decrease to no “snow”) u Mild (MR/LA ratio) <20% u Moderate (MR/LA ratio) 20–40% u Severe (MR/LA ratio) >40% Color flow jet area (select frame with largest jet, including mosaic) 2 u Mild <4 cm 2 u Moderate 4–10 cm 2 u Severe >10 cm Jet/vena contracta width* ME LAX; least sensitive to color gain, PRF, and atrial compliance (less valid with multiple jets) u Mild 0.3 cm u Moderate 0.3–0.69 mm u Severe ≥0.7 mm
Proximal Isovolumic Surface Area (PISA) (rarely performed intraoperatively) Based on the principle of flow conservation; the volume of blood that regurgitates through the regurgitant orifice is equal to the volume of blood converging toward the LV side of the MV in systole. LV blood accelerates as it approaches MV orifice (during regurgitation), causing aliasing seen as a change in color. (Figures 9.7 and 9.8) The larger the radius of color, the worse is the MR. Set color aliasing velocity so that flow convergence can be easily measured. *Vena Contracta: thinnest part of a jet as it traverses between two chambers during systole. Using the zoom mode, select the frame with the widest vena contracta.
4-chamber view LA
MR jet PML
r = radius of convergence zone Convergence zone LV
Figure 9.7 Schematic image from ME 4-chamber view of MR regurgitant jet and convergence zone. Flow acceleration in the region proximal to the regurgitant orifice forms concentric hemispheres of increasing isovelocity.
PISA flow = MRjet flow 2πr × PISAvel = EROA × MRvel 2
EROA = 2πr2 × PISAvel / MRvel PISAvel = aliasing velocity MRvel = peak velocity of MRjet EROA = effective regurgitant orifice area
Adult Echo X7-2t 13Hz 10cm
TIS0.5 MI 0.7 0
M4 M4 +56.2
2D 53% C 50 P Off Gen CF 48% 6482Hz WF 583Hz 4.4MHz
PAT T: 37.0C TEE T: 39.6C 87 bpm
Figure 9.8 ME 4-chamber view of MR. Note color aliasing velocity set at 56 cm/s. As the blood accelerates toward the regurgitant opening, it forms isovelocity shells. The line represents the radius of the proximal shell, “r.”
Effective Regurgitant Orifice Area (EROA) Mild
Mitral Inflow: Presence of MR increases the LA–LV pressure gradient because of dual filling of the atrium; from pulmonary veins (normal) and the LV (abnormal). Increased mitral E wave velocity >1.2 m/s is suggestive of severe MR. Pulmonary Venous Flow (LUPV): u As MR worsens, PVsystolic wave decreases, and PVdiastolic wave increases. u PVsystolic reversal always means severe MR 71
QUANTITATIVE Mitral regurgitant volume (RV) is based on the concept that the volume of blood passing through an orifice = area of the orifice × the velocity–time integral of the orifice. VTI is calculated from the CWD through the MV during diastole. RVmitral = SVmitral 2SVLVOT SVmitral = (MVA) × (MVVTI ) SVLVOT = (LVOTarea ) × (LVOTVTI ) LVOTarea = 0:785 d2 Mild <30 ml Severe >60 ml Regurgitant fraction (RF) is the ratio of the regurgitant volume to the total SV. RF = RVmitral / SVmitral Mild <30% Severe ≥ 50% Effective regurgitant orifice area (EROA) EROA = RVmitral =VTIregurg × jet Mild <0:20 cm2 Severe > 0:40 cm2
Signs of Severe MR 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
Coanda Effect: wall-hugging jet Jet reaches posterior LA wall Jet enters LAA Jet enters PV Width of jet ≥0.7 cm LA dilation (>5.5 cm) Flail leaflet/chord Emax velocity >1.2 m/s Pulmonary vein systolic flow reversal EROA ≥0.4 cm2 RV ≥60 ml/beat RF ≥50%
STANDARD DIAGNOSTIC EXAMINATION FOR MITRAL REGURGITATION (PRE-CARDIOPULMONARY BYPASS [CPB]) Systematically determine severity, location, and mechanism of MR by using 2D, CFD, and PWD. 2D: Evaluate for coaptation defect, leaflet structure, and LA size. Measure annulus size in ME LAX and commissural views. Evaluate for the possibility of postrepair Systolic anterior motion of mitral valve (SAM) by using the following criteria (Figure 9.9): • AL/PL (blue lines) ratio <1.3 is predictive. • C-sept (coaptation-septum) (red line) ≤2.5 is predictive.
LA A2 A1 P1
Figure 9.9 Schematic ME 4 chamber showing measurements to stratify SAM risk.
CFD: Evaluate for the following: • Jet area/LA >40% • VC ≥0.7 cm • Jet direction hints to mechanism PWD: pulmonary vein systolic reversal (Figure 9.10).
TEE X7-2t 33Hz 10cm
M4 M4 +56.2
CF 48% 6482Hz WF 583Hz 4.4MHz PW 50% WF 150Hz SV4.0mm 2.9MHz 3.2cm
2D 62% C 50 P Off Gen
Pulm Sys Vel Vel 28.2 cm/s PG 0 mmHg Pulm Dias Vel Vel 58.1 cm/s PG 1 mmHg Pulm S/D 0.5
80 40 cm/s
Systolic flow reversal
Figure 9.10 PWD of pulmonary vein flow showing systolic flow reversal.
UNIQUE INTRAOPERATIVE EXAMINATION (POST-MV REPAIR) • • •
Evaluate leaflet mobility. Examine for SAM (Figure 9.11). Obtain maximum and mean pressure gradients (e.g., rule out stenosis).
TIS0.1 MI 0.4
TEE X7-2t 53Hz 9.0cm
2D 49% C 50 P Off Gen
LA X3 G P
“SAM” of AML
PAT T: 37.0C TEE T: 38.1C
Figure 9.11 ME AV LAX view showing SAM of anterior leaflet of MV into the LVOT.
N OTE S