Mitral Valve Part I

The most common errors encountered in determining these parameters are (Quantitative volumetric method.)

(1) failure to measure the valve annulus accurately (error is squared in the formula), (2) failure to trace the modal velocity (brightest signal representing the velocity of the majority of blood cells) of the pulsed Doppler tracing, and (3) failure to position the sample volume correctly, and with minimal angulation, at the level of the annulus

Various Zones of the Mitral leaflets

(C) clear (R) rough (B) Basal

Describe the echo findings of mitral regurgitation for the following pathology: Ischemic Cardiomyopathy

(Leaflet tethering ) the leaflet area is deficient relative to the dilated left ventricle and the leaflets are stiffer and undergo fibrosis The prevalence rate of development of mild or greater MR after myocardial infarction has been estimated to be up to 50% and is associated with a worse prognosis. Patients who present with congestive heart failure from systolic dysfunction have an approximately 50% incidence rate of moderate or greater MR.

List common diseases of the mitral valve leaflets

1. Myxomatous disease 2. Rheumatic disease 3. Endocarditis 4. Marfan syndrome 5. Rare disorders such as • Infiltrative diseases (e.g., amyloid, sarcoid, or mucopolysaccharidosis) • systemic inflammatory disorders (e.g., systemic lupus erythematosus, or rheumatoid arthritis)

3 TYPES OF MV CHORDAE TENDINAE

1. Primary connect with the coaptation margins of the leaflets primary chorde that maintain coaptation of the leaflets failure of these corde lead to prolapse or flail leaflets 2. Secondary attach to the transition zone between rough and smooth leaflets basic support for length from pap to leaflet 3. Tertiary (Basal) very small in number arise from the basal myocardium provides structural support

three measures of regurgitation severity

1. The EROA, the fundamental measure of lesion severity. 2. The RVol per beat, which provides a measure of the severity of the volume overload. 3. The regurgitant fraction (RF) provides a ratio of the RVol to the forward SV specific to the patient

Discuss the shape and function of the mitral valve annulus

1. The mitral annulus is mostly a muscular structure that is attached to the left atrium by fibrous connections. 2. It is saddle shaped, with two high and two low points. 3. The region of the mitral annulus that is not muscular is the site of aortic mitral fibrous continuity.

Discuss mitral valve prolapse repair and review a case study

1. Triangular Resection Mitral Valve Repair 2. Abnormal segment has been removed. Leaflet edges are sewn together. 3. Annuloplasty completes the repair.

echocardiographic Parameters in the evaluation of valvular regurgitation

1. clinical information 2. image of the valve 3. Doppler echo of the valve 4. Quantitative Parameters of regurge 5. 3D echo 6. other echocardiographic data

the three components of the regurgitant jet need to be assessed:

1. flow convergence, 2. VC, 3. and the regurgitant jet direction and area into the receiving chamber

SAM has two main consequences:

1. flow is accelerated within the narrowed LVOT, creating a pressure gradient increase in afterload 2. disruption of normal leaflet coaptation, causing mitral regurgitation of variable severity (no coaptation) SAM results from the combination of septal hypertrophy, creating accelerated, posteriorly‐directed left ventricular outflow velocities, with a mitral valve susceptible to SAM because of elongated leaflets that are positioned anteriorly by displaced papillary muscles

Factors that are associated with worse prognosis in the mitral valve prolapse spectrum:

1. leaflet thickness of more than 5 mm 2. moderate or greater MR LV 3. LV ejection fraction of less than 50%.

The Mitral Valve vs The Tricuspid Valve

1. the MV has no septal insertion (septophobic) 2. The MV has direct continuity to AoV 3. MV has only two leaflets

the five anatomical components that form the mitral valve complex

1. the valves annulus 2. valve leaflets 3. commissures 4. tendinous cords 5. papillary muscles and LV myocARDIUM

The mitral valve area is increased, and LVOT obstruction relates to a combination of:

1. upper septal hypertrophy 2. leaflet elongation 3. papillary muscle displacement anteriorly and towards each other.

Sufficient Coaptation surface of Valves

8-10 mm Mitral Valve 4-10 mm Tricuspid Valves 1-2 mm semilunar valves

several core principles to pay attention to in order to maintain quality control of PISA

A.Timing of measurements Since the PISA calculation provides an instantaneous peak flow rate, the EROA calculated by this approach may not be equivalent to the average regurgitant orifice throughout the regurgitant phase. B. Duration of regurgitation: the issue of instantaneous versus average measurement comes particularly into play for ''partial'' regurgitation C. Shape of PISA: the standard method assumes that the valvular plane from which the regurgitant orifice arises is planar and that the flow convergence is homogeneous, but this is not always the case. D. Shape of the regurgitant orifice a factor that complicates PISA calculations is the shape of the regurgitant orifice itself.

Describe the etiology and mechanisms of mitral valve dysfunction Primary mitral regurgitation Secondary (functional) mitral regurgitation

AKA FUNCTIONAL MR 1. ischemic or myopathic LV remodeling 2. lateral displacement of the papillary muscles 3. tethering of the mitral leaflets 4. incomplete leaflet coaptation

AROA

Anatomic Regurgitant Orifice Area

tendinous cords (chordae tendineae)

Anchor valve, maintain vertical geometry, prevent prolapse of the mitral leaflet into the LA during systole Primary: insert into free edge of leaflets Secondary insert at junction of rough and clear zones Basal: attach to basal Zone

Mitral Commissures

Anterolateral and PosteroMedial Divides anterior /posterior leaflets the ends of the closure lines are the mitral annulus the tissue in this area is referred as the "commissure leaflets"

Explain aortic mitral continuity

Aortic Mitral Fibrous Continuity Aortic Mitral curtain Intervalvar Fibrosa ( ALL MEAN THE SAME THING ) the relationship between the MV and the Aortic Valve The anterior leaflet is in fibrous continuity with the noncoronary and left cusps of the aortic valve and hinges from the annulus with support at two commissures by the anterior and posterior papillary muscles

Quantitative volumetric method.

Because blood is incompressible, the total SV ejected by the ventricle in single-valve regurgitation is equal to the SVat the regurgitant valve (SVRegValv). If the forward SV (SVForward) is measurable simultaneously by Doppler or by any other method, the RVol can be calculated. The limitation of the method is the potential pitfall of underestimating true LV volume as noted above and therefore underestimating regurgitation severity.

Secondary MR

Distortion of the MV apparatus due to LV and/or LA remodeling. Most secondary MR is a disease of the LV

Quantitative pulsed Doppler method.

Doppler recording of VTI can be combined with 2D or 3D measurement of flow area to derive SVs at different sites The difference between inflow and outflow SVs of the same ventricle is caused by the RVol in single valvular regurgitation. forward SV at any valve annulus—the least variable anatomic area of a valve apparatus—is derived as the product of CSA and the VTI, measured by pulsed Doppler at the annulus.

FIBROELASTIC DEFICIENCY

Fibroelastic deficiency results from acute loss of mechanical integrity due to abnormalities of connective tissue structure and/or function

FC

Flow convergence

three components of a color flow regurgitant jet of MR

Flow convergence (FC) Vena Vontracta (VC), an Jet area

Calculations of SV can be made at two or more different sites: left ventricular outflow tract (LVOT), mitral annulus and right ventricular outflow tract (RVOT)

In the absence of regurgitation, SV determinations at these sites are equal. In the presence of regurgitation of one valve, without the presence of any intracardiac shunt, the SV through the affected valve is larger than through the other competent valves

Flow convergence method (proximal isovelocity surface area [PISA] method).

In valvular regurgitation, blood flow converges towards the regurgitant orifice forming concentric, roughly hemispheric shells of increasing velocity and decreasing surface area. Color flow mapping offers the ability to image one of these hemispheres that corresponds to the first aliasing threshold (where the displayed color changes from red to yellow) as one moves out from the regurgitant orifice. The radius of the PISA is measured from the point of color Doppler aliasing (abrupt change in color from blue to yellow if jet direction is away from transducer) to the VC. The PISA method is simple conceptually and in its practical calculation It allows a qualitative and a quantitative assessment of the severity of the regurgitation and has become the main method of quantification of regurgitation, particularly on the mitral and TVs.

Color doppler imaging and regurgitant values

Primary method for assessment of regurge severity (origin and size) a. jet characteristics and jet area b. vena contracta c. flow convergence

PISA

Proximal Isovelocity Surface area

PFC

Proximal flow convergence

ROA

Regurgitant Orifice Area

RF

Regurgitant fraction a ratio of the RVol to the total SV across affected valve

Rvol

Regurgitant volume an absolute measure of volume overload

Illustrate the Mitraclip procedure

Repair for Degenerative and Functional Mitral Regurgitation

Summarize the anatomy of the mitral valve

The mitral valve has two leaflets the anterior leaflet below the aortic valve, and the posterior leaflet composed of three scallops: P1, P2, and P3. At the leaflet edges, the chordae tendineae link the leaflets to the PM anchors on the left ventricular wall.

MITRAL VALVE DYSFUNCTION (Carpentier classification)

Type III leaflet motion is restrictive, commonly seen in the presence of LV dilation (secondary MR) or rheumatic MV disease or other post inflammatory conditions such as collagen vascular disease, radiation injury, carcinoid syndrome, or drug induced inflammatory changes.

VC

Vena Contracta

VCW

Vena Contracta Width

Mitral valve plasticity allows adaptation to __________________ , but adverse processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with worse prognosis

Ventricular remodelling

Flail

With chordal rupture, there is a flail segment of the leaflet such that the leaflet is displaced into the LA in systole, with the tip of the leaflet pointing away from the ventricular apex

Pulsed Doppler and quantitative assessment of valve regurgitation

a. Forward flow. forward stroke volume (SV) across the affected valve during the cardiac cycle is increased b. Flow reversal.

General Principles for evaluation valvular regurge with echo

a. comprehensive imaging b. integrated interpretation c. individualization d. precise language

BARLOW'S DISEASE

an excess of myxomatous tissue, which is an abnormal accumulation of mucopolysaccharides in one or both leaflets and many or only few of the chordae.

papillary muscles

anterior-lateral single body Bifurcates supplied by the LAD and the CX Posterior medial two bodies trifurcates supplied by PDA Prone to complications due to single coronary supply

Tenting

characterized by restricted leaflet motion, with tethering of valve closure resulting in the appearance of "tenting

Describe the echo findings of mitral regurgitation for the following pathology: Mitral Valve Prolapse (myxomatous mitral valve)

characterized histologically by increased mucopolysaccharides and thickening and disarray of the mitral valve leaflet. The leaflets and chordae are thick and redundant but with reduced tensile strength, so they are prone to progressive elongation or rupture. the leaflets are excessively long and increased leaflet compliance. Echo imaging demonstrates thick, redundant leaflets and chordae with systolic displacement of the leaflet tips into the LA in systole. Many patients with mitral valve prolapse have slowly progressive disease leading to severe MR with eventual mitral valve surgery. A more acute course may also be seen due to spontaneous chordal rupture, resulting in a partial flail leaflet segment.

Recording of jet velocity with _______________________provides valuable information as to the velocity and gradient between the two cardiac chambers involved in the regurgitation

continuous-wave Doppler (CWD) a. Spectral density. the signal density of the CWD of the regurgitant jet should reflect the regurgitant flow.term-14 A central jet well aligned with the ultrasound beam may appear denser than an eccentric jet of much higher severity, if not well aligned. b. Timing of regurgitation. The duration and timing of regurgitation can be valuable in the overall assessment of the physiology and hemodynamics of regurgitation. c. Time course of the regurgitant velocity. The spectral velocity profile of a regurgitant jet is determined by the pressure difference between the upstream and downstream chambers

Valve plasticity

defined as the potential for change in cellular phenotype and behavior

During ventricular contraction, the annulus ________________ with a gradual ___________ in annular area, height, and bending angle. This reaches its maximum at end systole and during the period of isovolumic relaxation.

descends, increase

Tethering

displacement of leaflet and papillary muscles related to abnormal tension via the chordae and dilatation of the left ventricle

Prolapse

displacement of the MV leaflet into the LA of >2mm with the leaflet tips directed toward the ventricular apex

Even in adult life, the mitral valve is a _____________ and therapeutically accessible

dynamic structure

limitations of PISA

eccentric jets may present a challenge, for both flow convergence and CWD recording In cases where this is not obvious, a display of simultaneous color and noncolor 2D images or turning off the color-flow imaging may be helpful. In cases where the regurgitant orifice is noncircular, as frequently is seen in functional MR (crescent shape), the PISA shape is also modified and no longer hemispheric. patients with multiple jets, the PISA method can be applied to each orifice, with flows and EROA added together; if one lesion is very mild, it can be neglected.

Describe the echo findings of mitral regurgitation for the following pathology: Hypertrophic Obstructive Cardiomyopathy

elongated leaflets contribute to both mitral regurgitation and left ventricular outflow tract (LVOT) obstruction, and are disproportionate to the reduced cavity size and abnormal LVOT The mitral valve contributes to subaortic obstruction in patients with HCM via systolic anterior motion (SAM) of the mitral leaflets towards the hypertrophied upper septum. This situation creates a long, slack distal residual leaflet portion interposed into the outflow stream at the beginning of ejection, so that ejection pushes this leaflet portion towards the septum

Mitral valve _________________ is an important determinant of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy and might be stimulated by valvular ventricular interactions

enlargement

Mitral valve disease is a major cause of ________ AND __________

heart failure and mortality

Proliferation

increase in numbers

During midventricular systole there is a dominant___________ motion of the annulus in an anterior-posterior direction. This helps maintain an oval shape just when the orifice area is at its ____________, with the added advantage of helping to keep the leaflets together.

inward, greatest

CMR study for assessment of LV function

it provides a view of the entire heart without limitations of imaging windows or body habitus, allows free choice of imaging planes as prescribed by the scan operator, is free of ionizing radiation, and does not require contrast administration CMR is an excellent modality for evaluating native valvular regurgitation. While echocardiography remains the first-line modality, CMR is indicated when: A. Echo images are suboptimal B Discordance exists between 2D echocardiographic features and Doppler findings C. Discordance exists between clinical assessment and severity of regurgitation by echocardiography In addition to quantifying the severity of regurgitation, a comprehensive CMR study will also quantitate cardiac remodeling (both atrial and ventricular) and provides insights into the mechanism of regurgitation.

Transient

lasting only for a short time; impermanent.

Redundant

leaflet that is too large or chordae that is too long

Differentiation

make or become different in the process of growth or development.

Myxomatous

mitral valve disease that is characterized by thickened, redundant leaflets and chordae with excessive motion and sagging of portions of the leaflets into the LA in systole

Genetic analysis has revealed that regulation of growth signaling, and cell migration pathways could potentially be modified to limit progression from developmental defects to clinically evident valve degeneration, such as ___________________

mitral valve prolapse

Echocardiography with Doppler is the primary modality for evaluation of __________________________

native valvular regurgitation

Color Doppler is the ___________ method for detection of regurgitation. In evaluating severity of regurgitation with color Doppler,

primary ,

Billowing

prolapse

Ischemic cardiomyopathy with tenting and tethering of the MV

pulling the annulus down

While color Doppler is important, ______ and _________are also essential in providing flow characteristics and dynamics. An integrative interpretation of valvular structure, cardiac size and function, and all Doppler parameters is crucial for assessing regurgitation severity, since each of these parameters has advantages and limitations.

pulsed and CWD

Mechanical stretch can ___________embryonic growth pathways.

reactivate The mitral valve is a dynamic cellular environment that actively adapts to superimposed stresses and is influenced by ventricular pathology.

With rapid ventricular filling there is a rapid ____________ in mitral valve area

reduction

Height, weight, body surface area, heart rate, rhythm, and blood pressure are required clinical parameters in the assessment of _____________

regurgitation.

Starting at end-diastole and with atrial contraction the annulus begins to contract, attaining its _____________ area just before ventricular systole, presumably to aid in a leaflet closure.

smallest

Opacity

the condition of lacking transparency or translucence

Genotype.

the genetic constitution of an individual organism

Describe the echo findings of mitral regurgitation for the following pathology: Flail mitral leaflet

the leaflet tip displaced into the LA with leaflet tip pointing away from the ventricular apex

Echo imaging and Valvular regurge evaluation

the main goal of echo imaging is to define the etiology, mechanism, severity, and impact of regurg on remodeling cardiac chamber a. Valve structure and severity of regurge b. impact of regurge on cardiac remodeling

Explain the mitral valve growth and development

the mitral valve develops from the endocardial cushion undergoes the process of EMT to generate brown cells undergo proliferation and differentiation into collagen secreting valve interstitial cell (VICs) (green) that become progressively aligned along the proximal-distal tissue axis. Finally, the valve elongates and thins. Valve growth and response to stress. In a growing or stressed valve, or a valve stimulated by transforming growth factor β (TGF β ), endothelial cells undergo EMT, increasing the number of matrix producing interstitial cells.

Vena Contracta (VC)

the point of lowest pressure and highest velocity downstream from a primary flow element high-velocity laminar flow measured in zoomed images very small measurement few mm

Phenotype

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Regurgitation severity may be difficult to assess, as it lacks a ____________ and is influenced by_____________ conditions. Quantitative parameters include RVol, RF, and regurgitant orifice area. Recommendations for grading severity of regurgitation are those of mild, moderate, and severe.

true gold standard, hemodynamic

MV Leaflet structure

| The leaflet structure is well organized, with a dense fibrous layer of collagen, known as the fibrosa, which arises from the mitral annulus and faces the left ventricle. The fibrosa is thicker close to the annulus and thinner at the edge of the leaflet. The fibrosa is covered by the spongiosa, a loose connective tissue layer rich in GAGs. The spongiosa is thicker at the leaflet edge and thinner at the annulus.The atrialis is made up of lamellar collagen and elastin sheets, which extend from the left atrial endocardium into the leaflet . Endothelial cells cover the valve. The deep subendothelial layers contain dormant VICs noncontractile, fibroblast like cells that originate from endocardial endothelial cells.