Valvular heart disease · Pathophysiology of aortic stenosis Aortic stenosis LV outflow obstruction Modified from Braunwald textbook of cardiovascular diseases LV = left ventricle

Valvular heart disease

Sergio Caravita, MD, PhD

Department of Management, Information and Production Engineering, University of Bergamo

Cardiology Unit, IRCCS Istituto Auxologico Italiano San Luca Hospital, Milano

[email protected]

23/03/2020

Heart valves

We have 4 cardiac valves, 2 in the left heart and 2 in the right heart, 2 atrio-ventricularvalves and 2 ventriculo-arterial valves:

- Mitral valve (left heart, separes the left atrium from the left ventricle)

- Aortic valve (left heart, separes the left ventricle from the aorta)

- Tricuspid valve (right heart, separes the right atrium from the right ventricle)

- Pulmonary valve (right heart, separes the right ventricle from the pulmonary artery)

Valves are thought to separe adjacent chambers in distinct phases of the cardiac cycle, allowing proper cardiac function:

- Atrio-ventricular valves are open during ventricular diastole, to allow ventricular fillingand close during ventricular systole

- Ventriculo-arterial valves are open during ventricular systole, to allow aortic and pulmonary blood flow, and close during ventricular diastole

Heart valves

Heart valves

Valvular physiology

Valves are thought to separe adjacent chambers in distinct phases of the cardiaccycle, allowing proper cardiac function:

- Atrio-ventricular valves are open during ventricular diastole, to allow ventricularfilling and close during ventricular systole

- Ventriculo-arterial valves are open during ventricular systole, to allow aortic and pulmonary blood flow, and close during ventricular diastole

When opened, valve orifices are large enough to accomodate increase in flow without generating significant transvalvular gradients (avoiding high pressure in the backward chamber)

When closed, valves are normally continent, even though a minimal regurgitationcan be visualized by modern technology (echocardiography)

Heart valves

2D, 3D and color-Doppler Echocardiography has revolutioned the noninvasiveassessment of cardiac valves

We can visualize and assess the morphology of all the cardiac valves by 2D and 3D echo

We can assess forward and backward flow taking advantage of color-Doppler echo

https://twitter.com/i/status/1237077581339537409






Valvular diseases

All heart valves can be affected by several pathologic conditions, leading to valve malfunctioning:

- Regurgitation (blood flowing back when the valve should be closed)

- Stenosis (narrowing of the valve orifice obstacling forward blood flow)

- Combination of regurgitation and stenosis

- the left heart is mainly a pressure pump

- the left heart pump blood throughthe high pressure systemiccirculation to several vital organs(systolic function)

- an increase in filling (diastolic) pressure of the left hearttransmittes backward to the lung, promoting pulmonary edema, impairing gas exchange and favoring dyspnea (breathlessness)

- the right heart is mainly a volume pump

- the right heart pump blood throughthe low pressure pulmonarycirculation to the lung for gas exchange, which is maintained evenwith low cardiac output

- An increase in filling pressure of the right heart transmittes backward to the peripheral vein, promoting fluidaccumulation in the recumbent part of the body

This contributes to explain why diseases affecting the right heart (or the right heartvalves), as compared with diseases affecting the left heart (or the left heart valves) can remain asymptomatic for a long time, have generally a slower course, and havebeen neglected by the medical and scientific community for quite a long time.

Keep in mind that:

Manifestations of valvular diseases

Management of valvular heart diseaseThe heart team

Valvular diseases: primary or secondaryregurgitation and stenosis

Primary (regurgitation or stenosis)

- There is a disease primarily affecting the valve or the valve apparatus

Secondary (regurgitation or stenosis)

- There is a disease affecting the cardiac chamber or the arterial vessel, leading to distorsion of the valve or of the valve apparatus

Valvular diseases

Left heart

- Aortic stenosis (frequent in the western world)

- Aortic regurgitation

- Mitral regurgitation

- Mitral stenosis (low frequency in the western world)

Right heart

- Tricuspid regurgitation

Aortic valveThe aortic valve is composed of three semilunar cusps attached to the aortic wall and forming in part, the sinuses of Valsalva.

The highest point of attachment at the leaflet commissures defines the sinotubular junction, and the most ventricular point (i.e., the nadir of the cusps) defines the annular plane.

The coaptation zone of the leaflets (lunulae) are more uniform in thickness except for a slightly more fibrous region at the anatomic midpoint of each cusp or nodules of Arantius.

Aortic stenosisEtiology

Predominant etiology: degenerative, calcific, age-related aortic stenosis

Risk factors: age and classic atherosclerotic risk factors (high cholesterol, diabetes, smoking, hypertension)

Alternative etiologies:

- Congenital malformations predisposing to stenosis (i.e. bicuspid aortic valve disease)

- Rheumatic disease

Bicuspid aortic valve

Two aortic valve cusps instead of three

Higher stress

Abnormalities in aortic flow promoting extracellular matrix dysregulation in aortic wallstructure

Higher risk for valve deterioration (earlier than for degenerative aortic stenosis)

Frequent association with aortic dilatation and aortic valve regurgitation

WSS=wall shear stress

Bicuspid aortic valveanatomical variants

Pathophysiology of aortic stenosis

Aortic stenosis

LV outflowobstruction

Modified from Braunwald textbook of cardiovascular diseases

LV = left ventricle


Aortic stenosis


↑ LV systolicpressure

LV hypertrophy, ↑ LV mass


CO = cardiac outputLA = left atriumLV = left ventricle


Aortic stenosis




LV dysfunction



LV dilation


Aortic stenosis




LV dysfunction

↑ LV diastolicpressure

↓ aortic pressure

↓ coronary arteryperfusion pressure

Myocardial ischemia

Myocardial O2

consumption

↓ CO during exerciseand then at rest

↑ LA pressurePulmonary edema



LV dilation

From aortic stenosis to heart failure

Symptoms of aortic stenosis

Myocardial ischemia





↑ LV diastolicpressure

Symptoms of aortic stenosis

Fatigue

Myocardial ischemia

Dyspnea





Angina

Syncope

DiagnosisEchocardiographyAortic valve

- Valve morphology

- Quantification of the severity of stenosis:

- Orifice planimetric area

- Transvalvular gradient

- Orifice «functional» area

Left ventricle

- Volume

- Geometry (concentric remodeling, concentric hypertrophy, eccentric hypertrophy)

- Systolic function (ejection fraction, deformation «strain» analysis)

- Diastolic function and pulmonary pressure

Ascending aorta

Left atrium

Other valvular diseases

Valve morphology and planimetric areaEchocardiography

Transvalvular pressure gradientEchocardiography

LV systolic functionEchocardiography

Left ventricular ejection fraction

(+/- stroke volume / end-diastolic volume)

Left ventricular global longitudinal strain

(systolic deformation of the left ventricle)

Other exams

Cardiac computed tomography

Quantification of calcium (calcium score)

Precise measures of aortic root and ascending aorta (good spatial resolution)

Anatomical assessment of coronaryarteries

Cardiac magnetic resonance imaging

Valve orifice area

LV volume and geometry

Cardiac catheterization

Measure the hemodynamic alterations

Treatment

Aortic valve replacement

Cardiac surgery (biological or mechanical prosthesis)

Transcatheter aortic valve replacement (biological)

Cardiac surgeryAortic valve replacement

Transcatheter aortic valve implantation/replacement (TAVI / TAVR)

https://www.youtube.com/watch?v=ZkgEf1EvRGc

https://www.youtube.com/watch?v=ZkgEf1EvRGc

Aortic regurgitation

Given the anatomy of the aortic valve, AR results from disease of either

- the aortic leaflets (primary AR) and/or

- the aortic root (secondary AR)

that results in valve malcoaptation

Aortic regurgitationetiology

Congenital leaflets abnormalities (bicuspid aortic valve)

Acquired leaflets abnormalities (senile calcifications, infective endocarditis, rheumatic disease, radiation- or toxic- induced valvulopathy)

Acquired aortic root abnormalities (systemic hypertension, idiopathic aortic rootdilatation…)

Congenital aortic root abnormalities

Pathophysiology of aortic regurgitation

Aortic regurgitation

Diastolicregurgitation

↑ LV volume (LV dilation)

↑ LV mass

LV dysfunction

↑ LV strokevolume

↓ effectivestroke volume

↓ myocardial O2

supply

Myocardial ischemia

Myocardial O2

consumption



CO=cardiac outputLA=left atrium

LV=left ventricle

↑ LV end-diastolicpressure


From aortic regurgitation to heart failure

Hemodynamics of aortic regurgitation

Symptoms of aortic regurgitation




LV=left ventricle

↑ LV end-diastolicpressure


Symptoms of aortic regurgitation





Fatigue

Dyspnea

Diagnosis of aortic regurgitationEchocardiographyAortic valve

- Valve morphology

- Quantification of the severity of regurgitation:

- regurgitant volume

- indirect signs (left ventricular dilatation with pressure overload)

Left ventricle

- Volume

- Geometry (concentric remodeling, concentric hypertrophy, eccentric hypertrophy)


- Diastolic function and pulmonary pressure

Ascending aorta

Left atrium


Other exams


Regurgitant volume



Hemodynamic alterations pathognomonic of valve disease

Treatment

Aortic valve replacement or repair

Cardiac surgery (repair vs biological or mechanical prosthesis)

Transcatheter aortic valve replacement (biological)

Cardiac surgeryAortic valve replacement

Cardiac surgeryAortic valve repair

Transcatheter aortic valve implantation/replacement (TAVI / TAVR)

Less evidence than for aortic stenosis

Off-label use of approved devices for aortic stenosis in accurately selected patients

Mitral valve

The MV apparatus includes the anterior and posterior mitral leaflets, the mitral annulus, chordae tendinae, papillary muscles, and the underlying LV myocardium.

Mitral regurgitationMechanisms

The mechanism of MR can be divided into two categories, based on whether the mitral leaflets exhibit significant pathological abnormality or not.

In primary MR, an intrinsic abnormality of the leaflets causes the MR, whereas secondary MR results from distortion of the MV apparatus due to LV and/or LA remodeling.

Primary MR

Myxomatous degeneration (mitral valve prolapse)

Fibroelastic deficiency (focal segmental pathology with thin leaflets)

Barlow's disease (diffuse thickening and redundancy, typically affecting multiple segments of both leaflets and chordae)

Secondary MR (atrial or ventricular MR)

The leaflets are intrinsically normal in secondary MR, although minor leaflet thickening and annular calcification can be present

Primary mitral regurgitation

Fibroelastic deficiency is usually seen in individuals older than 60 years.

It is often characterized by single chordal rupture and prolapse of an isolated scallop, most commonly the P2.

The associated mitral regurgitation jet is usually eccentric and directed opposite to the prolapsing scallop.

Barlow’s disease is typically seen in younger patients, 40–60 years old.

It is characterized by excess leaflet tissue.

The leaflets and the chordae appear thickened, redundant and elongated.

Multiple scallops of both anterior and posterior leaflets prolapse or may flail into the left atrium during systole.

These 2 forms of mitral valve prolapse represent the two ends of a spectrum. In clinical practice, most of the patients fall between these two extremes.

Primary MR

Fibroelastic deficiency

https://www-ncbi-nlm-nih-gov.proxy.unimib.it/pmc/articles/PMC6516795/figure/fig-3/

Barlow’s disease




Secondary mitral regurgitation(ventricular functional regurgitation)

Papillary muscle displacement occurs as a result of global LV enlargement or focal myocardial scarring, and can affect 1 or both papillary muscles, causing posteriorly directed or central MR

Secondary mitral regurgitation

Secondary mitral regurgitation

Secondary regurgitation

Secondary mitral regurgitation(atrial functional regurgitation)

The ventricle has generally normal geometry and ejection fraction

Typically, the atrium is severely enlarged

As opposed to ventricular functional regurgitation in which leaflets show significantly increased tethering, in atrial functional regurgitation the leaflets are usually flattened or only slightly tethered into the LV cavity, and the coaptation point is typically found at the annular plane.

In most of the cases of atrial functional regurgitation, the regurgitation jet is central

Annular and leaflet geometry by 3D echocardiography

Hemodynamics of mitral regurgitation

Acute vs chronic MR

Pressure and/or volume overload

Mitral regurgitation - pathophysiology

Small atrium – high pressure

Large atrium – normal pressure

Diagnosis of mitral regurgitationEchocardiographyMitral valve

- Valve morphology



- indirect signs

Left ventricle

- Volume


Left atrium and pulmonary pressure

Mitral annulus


Other exams


Regurgitant volume



Hemodynamic alterations pathognomonic of valve disease

Treatment

Mitral valve replacement or repair


Transcatheter mitral valve repair

Cardiac surgeryMitral valve replacement

Cardiac surgeryMitral valve repair

Mitral valve repairAlfieri’s stitch

Transcatheter mitral valve repair

https://www.youtube.com/watch?v=FVSzWP77nNo

https://www.youtube.com/watch?v=FVSzWP77nNo

Mitral stenosis

Mitral stenosisEtiology

Pathophysiology of mitral stenosisFrom mitral regurgitation to heart failure

Symptoms of mitral stenosis

Diagnosis of mitral stenosisEchocardiographyMitral valve

- Valve morphology



- indirect signs

Left ventricle

- Volume




Valve morphologyEchocardiography

Indirect signsEchocardiography

LV systolic functionEchocardiography

Other exams


…

…


Treatment

Mitral valve replacement


Transcatheter ………….

Cardiac surgeryMitral valve replacement

Transcatheter ()

Tricuspid regurgitation

Tricuspid regurgitationEtiology

Pathophysiology of tricuspidregurgitation From tricuspid regurgitation to heart

failure

Symptoms of tricuspid regurgitation

Diagnosis of tricuspid regurgitationEchocardiographyMitral valve

- Valve morphology



- indirect signs

Left ventricle

- Volume




Valve morphologyEchocardiography

Indirect signsEchocardiography

RV systolic functionEchocardiography

Other exams


Regurgitant volume


Treatment

Tricuspid valve replacement

Cardiac surgery (biological prosthesis)

Transcatheter tricuspid valve repair

Cardiac surgeryTricuspid valve replacement

Transcatheter tricuspid valve repair ()

Documents

Valvular heart disease · Pathophysiology of aortic stenosis Aortic stenosis LV outflow obstruction Modified from Braunwald textbook of cardiovascular diseases LV = left ventricle