Valvular Heart Disease: Difference between revisions

The four cardiac valves consist of either cusps or leaflets that close to prevent the blood from flowing backwards. When pressure behind the valve builds up, the valve opens, after blood has passed through, the pressure is reduced and the valve closes, actively or passively.

Valvular heart diseases are a major burden to society and it is expected that the prevalence will increase.  

== Pathophysiology ==

All cardiac valves have similar well defined interstitial cell layers, covered by endothelium.  The three cell layers have specific features, and are named fibrose, spongiosa, and the ventricularis.  During the cardiac cycle, the spongiosa rich in glycosaminoglycans, facilitates the relative rearrangements of collagenous and elastic layers.  Valvular interstitial cells (VIC) are abundant in all layers of the cardiac valves and comprise a diverse, dynamic population of resident cells. Regulation of collagen and other matrix components is ensured by enzymes, synthesized by VICs. Integrity of valvular tissue is maintained by interaction of valvular endothelial cells (VECs) with VICs. Changes and remodeling of valvular interstitial and endothelium cell leads to changes in properties of the valve and potentially also valve function.  

The tricuspid aortic valve separates the left ventricle outflow tract from the aorta.  Behind the three semilunar shaped cusps of the aortic valve are dilated pockets of the aortic root, called sinuses of Valsalva. The right coronary sinus gives rise to the right coronary artery, the left coronary sinus gives rise to the left coronary artery. The commissures are the areas where attachments of two adjacent cusps to the aorta meet.  

The commissure between the left en non coronary leaflets is positioned along the area of mitro-aortic continuity.  The three cusps ascend towards the commissures and descend to the basal attachment with the aorta. Opening and closure of the aortic valve is a passive, pressure driven mechanism in contrast to the mitral valve.  Tissue of the aortic cusps is stretched via backpressure in diastolic phase with elongation and stretching of elastin. In the systolic phase, recoil of elastin ensures relaxation and shortening of the cuspal tissue.<cite>Rajamannan</cite> Optimal functioning of the valve requires perfect alignment of the three cusps.

The mitral valve was named after a Mitre, by Andreas Vesalius (De Humani Corporis Fabrica, 1543).<cite>Di</cite> This active valve is located at the junction of the left atrium and left ventricle. The mitral valve apparatus contains five functional components; leaflets, annulus, chordae tendineae, papillary muscles and subajacent myocardium.  The annulus is a junctional zone of discontinuous fibrous and muscular tissue that joins the left atrium and ventricle. The anterior leaflet spans about one third of the primary fibrous, anterior part of the annulus. Part of the mitral valve anterior leaflet is in direct fibrous continuity with the aortic valve annulus, the mitro-aortic continuity. The posterior, ventricular leaflet is attached to the posterior predominantly muscular half to two third of the annulus. Due to the asymmetric leaflets, the mitral valve orifice has a funnel shape.

The mitral valvular complex comprises the mitral valve apparatus and left atrial en ventricular myocardium, endocardium and the mitro-aortic continuity. It contributes to the formation of the left ventricular outflow tract. The timed passage of blood through the valve as well as the tight closure during systole is facilitated by combined actions of the mitral valvular complex.<cite>Muresian</cite>

The structure of the pulmonary valve is analogous to the aortic valve structure. The leaflets are semilunar shaped, with semilunar attachments. The pulmonary valve has no traditional annulus. Anatomically, three rings can be distinguished, superior at the sinotubular junction, at the musculoarterial junction and a third ring at the base of the sinuses.<cite>MillWilcoxAnderson</cite>

The tricuspid valve is located at the junction between the right atrium and right ventricle. The tricuspid valve apparatus consists of 3 leaflets, chordae tendinae, an anterior, posterior and often a third papillary muscle. The peripheral ends of the septal, anterosuperior and inferior or mural leaflets are referred to as commissures. The tricuspid valve has no well defined collagenous annulus. The three leaflets are attached to a fibrous elliptic shaped annulus. The direct attachment of the septal leaflet is a distinctive feature of the tricuspid valve. The prominent papillary muscles support the leaflets at the commissures.   

Valvular insufficiency, defined as reverse flow caused by failure of a valve to close completely, may result from either intrinsic disease of the valve cusps or from damage to or distortion of supporting structures without primary cuspal pathology

=== Rheumatic valve disease ===

Chronic rheumatic valve disease is characterized by chronic, progressive deforming valvular disease. Anatomic lesions combine to varying degrees fibrous, or fibrocalcific distortion of leaflets or cusps, valve commissures and chordae tendineae, with or without annular or papillary muscle deformities.  

Obstruction of the left ventricle outflow can occur at subvalvular level (eg hypertrophic cardiomyopathy), supravalvular level or valvular level. Aortic valve stenosis is left ventricle outflow obstruction at valvular level.

Prevalence of aortic valve abnormalities increases due to age-related pathology in the ageing population.  

The first detectable macroscopic modifications of the calcification process is named aortic valve sclerosis. <cite>Rajamannan</cite> Aortic sclerosis, seen as calcification or focal leaflet thickening with normal valve function,  was detected in 25% of people at 65 years of age, this increases to 48% in people aged >75% in a population-based echocardiographic study.<cite>Otto</cite> <cite>Otto2</cite>

Calcified degenerative aortic valve stenosis was previously considered to be the result of a passive degenerative process due to longterm mechanical stress in combination with calcium accumulation. Recently this concept is revised. Calcified degenerative aortic stenosis is considered an active pathobiological process, including  proliferative and inflammatory changes, lipid accumulation, renin-angiotensin system activation, valular interstitial cell transformation, ultimately resulting in calcification of the aortic valve.<cite>RajamannanGershBonow</cite><cite>Rajamannan2</cite> <cite>OBrien</cite> <cite>Mohler</cite> Risk factors for development of calcific aortic stenosis are similar to those for vascular atherosclerosis such as diabetes, hypertension, and cholesterol levels.<cite>Stewart</cite> <cite>Stritzke</cite>  Progressive calcification leads to immobilization of the cusps causing stenosis.

Aortic stenosis is assessed by estimating the mean systolic pressure gradient and aortic valve area (AVA). The normal aortic valve area is 3-4 cm2.  Mild aortic stenosis is defined as an aortic valve area 1.5 cm2, mean gradient less than 25 mm Hg, or jet velocity less than 3.0 m per second, moderate aortic stenosis as an area of 1.0 to 1.5 cm2, mean gradient 25 to 40 mmHg, or jet velocity 3.0 to 4.0 m per second. A valve area of <1 cm2,  a mean gradient greater than 40 mm Hg, or jet velocity greater than 4.0 m per second  implies severe aortic stenosis The valve area may decrease by as much as 0.12 ±  0.19cm2  per year.<cite>OttoBurwaskLegget</cite> In late stages of severe aortic stenosis, cardiac output declines due to systolic dysfunction of the left ventricle, with a decline in the transvalvular gradient.

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!Aortic stenosis severity

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Symptoms of degenerative aortic stenosis manifest with progression of the disease. The first symptoms usually commence in the seventh or eight decade. Symptoms are typically noted on exertion. Dyspnoea on exertion is the most common encountered first symptom. Other symptoms are angina, precipitated by exertion and relieved by rest, syncope and heart failure. The findings on physical examination vary with the severity of the disease. On auscultation, a systolic ejection crescendo-decrescendo murmur, radiating to the neck is audible, often accompanied by a thrill. An elevated left ventricular pressure in patients with aortic stenosis, in conjunction with mitral annulus calcifications predisposes to rupture of mitral chordae tendineae, which may produce a regurgitant systolic murmur.<cite>Brener</cite> <cite>Mihaljevic</cite>

When stroke volume and systolic pulse pressures fall in severe aortic stenosis, a pulsus parvus (small pulse) may be present. A wide pulse pressure is also characteristic of aortic stenosis. A pulsus parvus et tardus (the arterial pulse is slow to increase and has a reduced peak) can be appreciated by palpating the carotid pulse of patients with severe aortic stenosis. The stenotic valve decreases the amplitude and delays the timing of the carotid upstroke. Rigidity of the vasculature may hamper this sign in the elderly.

In aortic stenosis, cardiac silhouette and pulmonary vascular distribution are normal unless cardiac decompensation is present. Post-stenotic dilatation of the ascending aorta is frequent. Calcification of the valve is found in almost all adults with severe aortic stenosis; however, fluoroscopy may be necessary to detect it. A late feature in patients with aortic valve stenosis is cardiomegaly. In patients with heart failure, the heart is enlarged, with congestion of pulmonary vasculature.  

In approximately 85% of patients with aortic stenosis, left ventricle hypertrophy, with or without repolarization abnormalities is seen on electrocardiography (ECG). Left atrial enlargement, left axis deviation and conduction disorders are also common. Atrial fibrillation can be seen at late state and in older patients or those with hypertension.  

The best non-invasive diagnostic tool to confirm the diagnosis of aortic stenosis, assess the number of cusps and the annular size, is ultrasonic examination of the heart. Quantification of valvular calcification is possible. In 1998, the American college of cardiology/American Heart Association (ACC/AHA) task force <cite>Bonow</cite> recommended the diagnostic use of echocardiography.

Valve thickening and calcification, as well as reduced leaflet motion can also be assessed using Doppler.  

Although the role of computed tomography (CT) in clinical management is currently not well defined, this imaging modality could improve assessment of the ascending aorta. CT has an established role in evaluating the presence and severity of aortic root and ascending aortic dilatation in patients with associated aortic aneurysms. The high sensitivity and specificity of CT in detecting high-grade coronary artery stenosis could be useful to preoperatively rule out coronary artery disease.

Both electron beam and multislice cardiac CT can be useful in quantifying valve calcification, which have been shown to correlate with echocardiographic assessment and clinical outcome.  Prior to transcatheter aortic valve implantations, CT provides information concerning the aortic valve area, annulus size, and the distance between the aortic cusps and the coronary ostia.  

Cardiac MRI (CMR) has an established role in evaluating aortic root and ascending aorta anatomy. It can be used to measure the aortic valve area, but the role of CMR in the management of aortic stenosis is currently not well defined.  

Cardiac catheterization remains the gold standard to detect coronary artery disease. Currently, in patients with aortic stenosis, cardiac catheterization is most often performed to identify the presence of concomitant coronary artery disease (CAD). In patients with inconclusive noninvasive tests, hemodynamic abnormalities can be assessed by cardiac catheterization. Coronary angiography is recommended prior to aortic valve replacement.  

Since aortic stenosis is a progressive disease, most common in the elderly population, many patients with aortic stenosis do not recognize gradually developing symptoms and cannot differentiate fatigue and dyspnea from aging and physical deconditioning. Lifestyle modification may mask symptoms. Although contraindicated in patients with severe aortic stenosis, Exercise testing is useful for risk stratification and eliciting symptoms. Under supervision, it is reasonable to propose exercise testing in patients >70 years who are still highly active.  

For many years the standard of care for patients with significant aortic valve stenosis has been to provide antibiotic prophylaxis against infective endocarditis.  However, current AHA guidelines for prevention of infective endocarditis no longer recommend antibiotic prophylaxis for this group of patients. Exceptions are patients with a prior episode of endocarditis, patients with prosthetic valves or with additional complex cardiac lesions with a high risk for the development of endocarditis.  Patients who have had rheumatic fever should still receive antibiotic prophylaxis against recurrences of rheumatic fever  

   

No medical treatment has proven to delay the progression of aortic stenosis. Surgery is inevitable for symptomatic patients. Patients at prohibitive risk for intervention may benefit from medical treatment including digitalis, diuretics, ACE inhibitors, or angiotensin receptor blockers, if experiencing heart failure. Beta-blockers should be avoided in these circumstances.  

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!Current Guidelines  

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|'''Class IIa'''

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#AVR may be considered for asymptomatic patients with severe AS and abnormal response to exercise (e.g., development of symptoms or asymptomatic hypotension). (Level of Evidence: C)

#AVR may be considered for adults with severe asymptomatic AS if there is a high likelihood of rapid progression (age, calcification, and CAD) or if surgery might be delayed at the time of symptom onset. (Level of Evidence: C)

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|'''Class III'''

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The infinitive treatment for aortic valve stenosis is aortic valve replacement.  

In 1962 Donald Ross implanted the first aortic valve allograft. In 1967 he replaced a patient’s malfunctioning aortic valve with the patients own pulmonary valve. An aortic or pulmonary valve homograft was then used to replace the patient’s pulmonary valve. This procedure is known as the Ross Procedure.  Currently, the Ross procedure may be considered for bicuspid aortic valve stenosis, in particular for young women of reproductive age.   

In 2002, the first transcatheter aortic valve implantation was performed by Dr. Alain Cribier <cite>Cribier</cite>. A transcatheter aortic valve implantation is a less invasive treatment option for patients at prohibitive risk for conventional aortic valve replacement.  In this technique, the native valve is not excised. After balloon valvuloplasty, the prosthetic valve is implanted in the aortic position, with the frame of the prosthesis covering the native valve. The bioprosthesis can be implanted retrograde or antegrade. Currently 4 different approaches may be used in this technique. (table…). Transcatheter aortic valve implantation is assessed in randomized clinical trials and registries.  

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|Transfemoral, retrograde

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Aortic valve stenosis has a severe prognosis when any symptoms are present, with survival rates of only 15–50% at 5 years. Strongest predictors of poor outcome in the elderly population are  high New York Heart Association (NYHA) class (III/IV), associated mitral regurgitation and left ventricular dysfunction. Survival is only 30% at 3 years with the combination of these three factors.  

== Bicuspid Aortic valve ==

Bicuspid Aortic valve disease affects as many as 1-2% of the population, and is the most frequent congenital cardiovascular malformation in humans.<cite>Fedak</cite>  

Although endocarditis can be a devastating complication of bicuspid aortic valve disease, straightforward bicuspid aortic valve disease is no longer an indication for bacterial endocarditis prophylaxis according to the ACC/AHA practice guidelines. The risk of endocarditis is felt to be low in patients with straightforward bicuspid aortic valve disease. An exception to this recommendation is a patient with a prior history of endocarditis.<cite>Nishimura</cite>

=== Clinical Presentation ===

In infancy, bicuspid aortic valve disease is often asymptomatic. By adolescence an estimate 1 of 50 children born with these abnormalities will have clinically significant obstruction or regurgitation.<cite>Bonow2</cite>

Complications of bicuspid aortic valve disease are common in adulthood.<cite>Tzemos</cite> The abnormal shear stress leads to valve calcification and further aortic root dilation has been reported. <cite>Bonow3</cite> The most common complication is aortic stenosis, caused by premature fibrosis, stiffening, and calcium deposition. The majority of patients under 65 years of age with significant aortic valve stenosis have bicuspid aortic valve disease. A more rare complication of bicuspid aortic valve disease is aortic regurgitation. 15% of all cases of aortic regurgitation in the Euro Heart survey had bicuspid aortic valve disease.  On auscultation, an ejection sound can be audible, best heard at the apex. There may be associated murmurs of aortic stenosis, incompetence, or coarctation of the aorta when these lesions are present.  

=== Diagnostic options ===

Echocardiography is used to confirm the diagnosis of bicuspid aortic valve disease. Reported sensitivities and specificities of echocardiography for detecting BAV anatomy are 92% and 96% respectively. To establish the diagnosis, visualization of the aortic valve in systole in the short-axis view is essential. During diastole, the raphe can make the valve appear trileaflet. In the long-axis view, the valve often has an eccentric closure line and there is doming of the leaflets.  Transesophageal echocardiography may improve visualization of the leaflets in case of inconclusive transthoracic echocardiography.

In all patients, serial transthoracic echocardiography should be performed to evaluate the valve and disease progression.  Annual cardiac imaging is recommended for patients with significant valve lesions or with aortic root diameters >40 mm. Complete imaging of the thoracic aorta should be performed periodically for surveillance.<cite>SiuSilversides</cite>

The thoracic aorta is visualized by alternative imaging modalities such as cardiac magnetic resonance imaging (MRI) or computer tomography (CT). Both cardiac MRI and CT images can help to confirm the bicuspid anatomy of the aortic valve.   

=== Treatment ===

==== Medical treatment ====

In patients with bicuspid aortic valve disease, high blood pressure should be treated aggressively. The ACC/AHA guidelines for the management of adult congenital heart disease and guidelines for the management of patients with valvular heart disease suggest that it is reasonable to use beta-blockers in this population (Class IIa recommendation).<cite>Warnes</cite> This is in accordance with the standard of care at many centers to slow the progression in Marfan-associated aortopathy.

Guidelines suggest that changes in root size more than 0.5 cm/year are an indication for root replacement. Aortic root dimensions of 5.0 cm require intervention and aortic root dimensions of 4.5 cm require intervention if surgery is performed for valvular indications according to current guidelines.  

=== Prognosis ===

Life expectancy in adult patients with bicuspid aortic valve disease is not shortened when compared to the general population. 10-year survival in asymptomatic adults with bicuspid aortic valve disease with a spectrum of valve function, was 96%.<cite>Tzemos</cite> In asymptomatic adults with bicuspid aortic valve disease without significant valve dysfunction the 20-year survival was 90%.<cite>Michelena</cite>

== Aortic Regurgitation ==

A variety of aetiologies can cause aortic regurgitation by preventing proper coaptation of the aortic valve leaflets with a subsequent diastolic reflux of blood from the aorta into the left ventricle. Etiology of aortic regurgitation can be primary valvular, or it can be primarily caused by aortic root or disease.   

   

Aortic annulus dilation, without primary involvement of the leaflets may result in aortic regurgitation due to leaflet separation. Aortic regurgitation of primary aortic root or annulus aetiology includes idiopathic aortic root dilatation, aortic dissection, trauma, and chronic severe systemic hypertension. Aortitis represents less than 5% of the aetiologies of aortic regurgitation and may be due to inflammatory disease, such as giant cell, Takayasu and Behcet syndrome. Syphilis and ankylosing spondylitis may affect the aortic valve, but may also be associated with aortic dilatation. Other systemic arteritides and connective tissue disorders such as Marfan syndrome, Reiter disease, Ehlers-Danlos syndrome, osteogenesis imperfecta, and rheumatoid arthritis can lead to annular dilatation and valvular insufficiency. In patients without generalized tissue disease the same pattern of ascending aortic enlargement is known as annuloaortic ectasia. Chronic aortic regurgitation itself may lead to progressive aortic root dilatation.

It is of considerable clinical importance to distinguish between acute aortic regurgitation and chronic regurgitation since acute aortic regurgitation can be life-threatening if not treated immediately, in contrast to chronic regurgitation which can be tolerated for years.  

=== Pathophysiology ===

In patients with aortic insufficiency the regurgitating volume increases the total stroke volume. This volume might equal the effective forward stroke volume in patients with severe aortic regurgitation. In chronic aortic regurgitation, several compensatory mechanisms ensure cardiac output.

==== Chronic Aortic regurgitation ====

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!Causes of chronic aortic regurgitation 

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=== Clinical presentation ===

Patients with aortic regurgitation typically present with symptoms of left sided heart failure including dyspnea on exertion, orthopnea, fatigue, and occasionally paroxysmal nocturnal dyspnea. Angina is less common in patients with aortic regurgitation compared to aortic stenosis. The reduced aortic diastolic blood pressure reduces the coronary blood flow, resulting in angina. The same mechanism is presumed to cause syncope.  

=== Diagnostics ===

==== Chest Radiography ====

Chest Radiography in acute aortic regurgitation reveals minimal cardiac enlargement, with normal aortic root and arch. In acute aortic regurgitation, signs of left heart failure are frequent.  Cardiomegaly with left ventricular enlargement is the main feature on chest radiography in chronic aorta regurgitation. The ascending aorta may be enlarged in case of an aortic aneurysm or aortic dissection but Chest X-ray is not a sensitive examination to detect ascending aortic aneurysm.  

Preoperatively transoesophageal echocardiography is performed to more accurately evaluate the anatomy and mechanism of the aortic valve regurgitation

=== Treatment ===

The only direct method to reduce aortic regurgitation is surgical treatment. However, some patients may benefit from medical treatment.   

The relative reduction of myocardial blood supply due to increased demand and/or associated obstructive coronary artery disease may cause angina. Angina may be treated by reducing aortic regurgitation, reduction of myocardial demand of revascularization of the myocardium. Clinical heart failure is treated with traditional therapy, including digitalis, diuretics, and ACEI. In severe heart failure, parenteral inotropic and vasodilator therapy may be needed.   

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!Current Guidelines: Medical treatment of Aortic Regurgitation

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|'''Class I'''

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|'''Class IIa'''

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|'''Class IIb'''

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|'''Class III'''

Although the prosthetic valve replacement remains the standard for aortic valve regurgitation, aortic valve repair procedures are performed with a combination of different surgical techniques.  The quality of the cusps is essential for repair. The annulus and sinotubular junction can be surgically readapted to the cusps, eliminating the regurgitation.

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!Current Guidelines 

== Mitral Stenosis ==

=== Etiology and pathology ===

The leading cause of mitral stenosis is rheumatic fever, causing postrheumatic deformities. Other rare aetiologies of left atrial outflow obstruction include congenital and degenerative mitral valve stenosis, severe mitral annular and/or leaflet calcification carcinoid disease, neoplasm, left atrial thrombus, infective endocarditis with large vegetations, certain inherited metabolic disorders such as Fabry’s disease, mucopolysaccharidosis,  Whipple’s disease, gout, rheumatic arthritis,  lupus erythematosus, methysergide therapy, and cases related to previous implanted prosthesis or commisurotomy.

   

   

The area of the normal mitral valve orifice is 4-6 cm2. In patients with mitral stenosis, when the valve area approaches 2 cm2 or less, an early, mid and late diastolic transvalvular gradient is present between the left atrium and ventricle. With progressive mitral stenosis, transvalvular pressure gradient increases. Mitral transvalvular flow depends on cardiac output and heart rate. Shortening of diastolic phase in increased heart rate causes symptoms by reducing forward cardiac output.  Mitral stenosis develops gradually, and may be asymptomatic for years.

=== Clinical presentation ===

Patients with mitral stenosis may be asymptomatic for years. Mean age of presentation of symptoms is fifty to sixty years old. The presenting symptom in patients with mild mitral stenosis is typically dyspnea precipitated by stress or atrial fibrillation. Progression of disease with increasing left atrial and pulmonary venous pressures will cause progressive dyspnea. At advanced stage, patients are often thin and frail and complain of weakness and fatigue due to low cardiac output. When pulmonary hypertension and right ventricular failure develop, signs of tricuspid regurgitation, abdominal discomfort due to hepatomegaly and ascites can be present.

During systole, combined papillary muscle contraction and contraction of the dynamic annulus promote leaflet coaptation. Calcification of the annulus may hinder the sphincter-like contraction of the annulus allowing regurgitation. Secondary mitral regurgitation due to annulus dilation may be caused by ischemic or dilated cardiomyopathy.  The regurgitant volume causes left ventricular enlargement and contractile dysfunction.  Left ventricle dilation may cause enlargement of the mitral annulus and the regurgitant orifice, increasing the mitral regurgitation. Positive inotropes, diuretics and vasodilators reduce the size of the left ventricle and the regurgitant orifice, and decrease the regurgitant flow.

=== Etiology ===

Three different types of primary mitral regurgitation can be defined; leaflet retraction from fibrosis and calcification, annular dilatation and chordal abnormalities (including rupture, elongation, or shortening). Functional mitral regurgitation results from LV dysfunction with or without annular dilation. Mitral regurgitation was classified by Carpentier into three types based on leaflet and chordal motion: normal leaflet motion (type I), leaflet prolapse or excessive motion (type II), and restricted leaflet motion (type III).<cite>FannIngelsMiller</cite>

=== Chronic mitral valve regurgitation ===

Degenerative mitral valve disease is the most common cause of mitral regurgitation in Europe.   

Mitral regurgitation in Barlow syndrome or parachute mitral valve is due to annular dilatation and extensive hooding of leaflets with large amounts of excessive leaflet tissue. In mitral regurgitation, the mass-to-volume ratio of the enlarged, thin walled left ventricle is less than one.<cite>FeiringRumberger</cite>   

=== Clinical Presentation ===

Patients with mild to moderate compensated chronic mitral regurgitation may remain asymptomatic for many years. The adapted left ventricle maintains normal forward cardiac output. The left ventricle ejection fraction in chronic mitral regurgitation may be greater than normal due to the compensatory cardiac adaptations. Progression of severity depends on etiology of regurgitation; in patients with connective tissue disease regurgitation tends to progress more rapidly than patients with mitral valve prolapse or rheumatic mitral regurgitation. Progression in acute rheumatic fever is often rapid. Acute progression may by caused by endocarditis or chordae rupture.  

Early in the disease process of patients with Barlow syndrome, a characteristic midsystolic click can be appreciated, followed by a late systolic murmur; with disease progression the murmur becomes holosystolic, and the midsystolic click may become inaudible.<cite>FannIngelsMiller</cite>

=== Acute mitral regurgitation ===

Immediate intervention is often necessary in acute mitral regurgitation. Etiology can be organic or functional. Organic causes include rupture of a major chorda tendinea (in myxomatous mitral valve disease) or papillary muscle (due to myocardial infarction), leaflet perforation (of endocarditic origin), and dysfunction of a prosthetic valve due to endocarditis or paravalvular regurgitation. Regurgitation of functional etiology results from left ventricular abnormalities such as dyskinetic wall due to ischemia or dilated ventricle due to cardiomyopathy.  

On physical examination no signs of cardiac compensatory mechanisms are present. The increase in left atrial pressure diminishes the pressure gradient between the left ventricle and left atrium by midsystole. The murmur of mitral regurgitation is shortened and of decreased intensity, it may be soft, short of even inaudible. An S3 gallop usually is present. The volume overload is increasing the severity of MR over time, and leads to a greater percentage of the LV stroke volume being ejected in a retrograde fashion.  

=== Diagnostic Options ===

==== Chest Radiography====  

In chronic mitral regurgitation chest radiography demonstrates enlargement of the left ventricle and atrium. The mitral annulus may be calcified. In acute mitral regurgitation, no adaptive left atrium or ventricle enlargement has developed. Signs of interstitial or alveolar pulmonary edema may be present.

==== Cardiac Catheterization====  

Coronary ischemic causes of mitral regurgitation can be identified by cardiac catheterization.  

=== Treatment ===

==== Surgical ====

The hemodynamic overload on the heart caused by mitral regurgitation can ultimately only be corrected by surgically restoring valve competence. For all valve surgery timing of surgery is essential. Irreversible left ventricular dysfunction will result in suboptimal results indelayed surgery. Due to the operative risk and risk of valve prosthesis surgery should however be delayed as long as possible  

The normal valve area of the tricuspid valve is 7–8cm2. Reduction of valve area to <2 cm2 causes a pressure gradient. A small diastolic pressure gradient (<5 mmHg), gradient between the right atrium and ventricle can be present due to tricuspid stenosis. The gradient is increasing on inspiration. A mean pressure gradient >5mmHg is considered indicative of significant TS and is usually associated with symptoms  

A tricuspid opening snap and a characteristic mid-diastolic murmur may be audible along the left sternoid border on auscultation. Carvallo’s sign, an increase of murmur intensity on inspiration, may be present. Distention of jugular veins, ascites, pleural effusion and peripheral edema may be present due to increased right atrial pressures.

Reduced cardiac output causes symptoms of fatigue and malaise. The pulmonary congestion of mitral stenosis may be masked in severe tricuspid stenosis.  

=== Diagnostic Options ===

==== Chest radiography ====

Cardiomegaly with an increase in right atria and pulmonary artery size is demonstrated on chest radiography.

Tricuspid stenosis due to rheumatic disease is characterized by leaflet thickening with reduced motion and frequent commissural fusion.  The chordae are shortened and thickened, and diastolic doming is present.  Carcinoid syndrome is characterized by retraction of leaflets towards the apex during systole. A prolonged slope of antegrade flow across the tricuspid valve can be seen on Doppler. Tricuspid stenosis is considered severe when the mean transvalvular gradient is >5 mmHg.  

=== Treatment ===

The therapeutic approach for tricuspid regurgitation is dictated by the aetiology of the regurgitation and overall condition of the patient.  In a limited number of patients percutaneous balloon tricuspid dilatation has been performed. This is a treatment option in cases of isolated and pure tricuspid stenosis, but it frequently induces regurgitation.<cite>Vahanian1</cite> Tricuspid balloon valvotomy, combining commissurotomy leaflet augmentation and annuloplasty, can be used to treat tricuspid stenosis; however, with this treatment the potential for inducing severe tricuspid regurgitation still exists. A biological prosthesis is preferred in case of tricuspid valve replacement,since it heas satisfactory long-term durability and mechanical prosthesis caries a higher risk of thrombosis.

Functional tricuspid regurgitation results from distortion of the architecture and coordinated actions of the tricuspid leaflets, annulus, chords, papillary muscles, and right ventricular (RV) wall. This distortion is most commonly caused by right ventricular dilation and dysfunction from left sided heart disease with pressure/volume overload conditions.  

Right ventricular infarction with severe regional wall motion abnormality or disruption of the papillary muscle may cause regurgitation. Right ventricular dilatation with annular enlargement and valvular incompetence can be seen in Eisenmenger syndrome and pulmonary hypertension.

=== Clinical presentation ===

A reduction in cardiac output related to tricuspid regurgitation, may cause symptoms of fatigue and weakness. Right-sided heart failure may cause ascites, congestive hepatosplenomegaly, pulsatile liver, pleural effusions, and peripheral edema.

With progression of the disease, patients become cachexic, cyanotic and jaundice may be present. A parasternal pansytolic murmur increasing on inspiration may be appreciated on auscultation(Carvallo’s sign).  An S₃, increasing with inspiration and decreasing with a Valsalva maneuve may be audible, as well as an increased P₂ if pulmonary hypertension has developed.

=== Diagnostic options ===

==== Chest Radiography ====

Cardiomegaly, increased right atrial and ventricular size and a prominent azygous vein can be demonstrated on chest x-ray. Chest Radiography may reveal pleural effusion, and ascites by upward diaphragmatic displacement.  

==== Cardiac catheterization ====

Cardiac catheterization is not necessary to diagnose tricuspid regurgitation. Increased right atrial and right ventricular end-diastolic pressures and the degree of pulmonary artery hypertension can be evaluated by catheterization. Pulmonary artery pressures of over 60 mmHg are usually due to left-sided lesions leading to secondary tricuspid regurgitation.

=== Treatment ===

Treatment strategy for tricuspid regurgitation is dictated by the aetiology and the underlying cause of the disease and the overall condition of the patient. Primary tricuspid regurgitation has a poor prognosis without treatment. Functional tricuspid regurgitation may improve following treatment of its cause. Correction of concomitant mitral regurgitation may worsen tricuspid regurgitation. Risk factors for persistence or worsening of tricuspid regurgitation are reduced right ventricular function and the diameter of tricuspid annulus.  

==Pulmonary valve stenosis==

===Etiology and pathology===

Pulmonary valve stenosis can be caused congenital, carcinoid and rheumatic disorders or extrinsic compression. The typical domeshaped pulmonary valve stenosis is the most common form of right ventricular outflow tract obstruction. Stenosis is caused by fusion of the pulmonary valve leaflets and a narrowed central orifice. The valve is usually mobile and associated with medial abnormalities and dilation of the pulmonary trunk.  

Pulmonary valve stenosis may be associated with Noonan, Williams, Alagille, Keutel or rubella syndromes.<cite>Elizabeth</cite>  

===Clinical presentation===

Most patients with mild to moderate pulmonary valve stenosis are asymptomatic. Severe pulmonary valve stenosis may cause exertional dyspnea and fatigue, chest pain, palpitations and syncope.   

On physical examination, thrill along the left sternal edge, and a long systolic ejection murmur with late peak may be appreciated. S2 may be widely split with reduced or absent P2.

===Diagnostic options===

====Chest Radiography====  

Chest radiography may show dilated pulmonary arteries, occasionally with calcification of the pulmonic valve. In case of severe pulmonary valve stenoisis, oligemic lung fields can be seen.

====Cardiac catheterization====

Cardiac catheterization is not necessary to diagnose pulmonic valve stenosis.  Hemodynamic consequences and severity of pulmonary valve stenosis can be assessed with cardiac catheterization.

===Treatment===

Invasive intervention is recommended in case of symptomatic disease, or when the gradient across the valve is >40 mmHg.  

====Surgical====

The treatment of choice for stenosis at the valvular level is balloon valvuloplasty. Long-term results are satisfactory and the procedure relatively safe. Surgical valvotomy is very effective with minimal recurrence, however significant pulmonary regurgitation may occur.

==Pulmonary valve regurgitation==

===Etiology and pathology===

Physiologic pulmonic regurgitation, qualified as trace to mild, is present in nearly all individuals. Pulmonary valve regurgitation can be caused by valvular disease such as infective endocarditis (rarely involves pulmonic valve) or connective tissue disease, carcinoid, congenital heart disease, or it can be secondary to pulmonary hypertension, which causes dilation of the valve ring. Pulmonic regurgitation can result in impairment of right ventricular function and eventual clinical manifestations of right-sided volume overload and heart failure.

===Clinical presentation===

Patients are often asymptomatic. Symptoms of right-sided heart failure develop when the severity and duration of the regurgitation results in right ventricular enlargement and decompensation. Symptoms include dyspnea on exertion, light-headedness, lethargy, peripheral edema, chest pain, palpitations, and abdominal pain. Often these symptoms are accepted by the patient and attributed to poor physical fitness, causing a delay in presentation.   

The jugular venous pressure is usually increased in pulmonary valve regurgitation.  

A palpable impulse may be present at the left lower sternal border due to right ventricular enlargement. On auscultation P2 may be delayed due to increased right ventricular end-diastolic volume and increased ejection time with large stroke volume. P2 can be accentuated in case of pulmonary hypertension,

The murmur of pulmonary regurgitation is heard best at the third to fourth intercostal space along the left sternal border and increases with inspiration.

===Diagnostic options===

====Chest Radiography====  

Chest radiography of patients with pulmonic regurgitation with tricuspid regurgitation may demonstrate cardiomegaly and enlargement of the right-sided heart contour. Pure pulmonic regurgitation may to have specific signs on chest radiography. Prominent central pulmonary arteries with enlarged hilar vessels and loss of vascularity in the peripheral lung fields suggest severe pulmonary hypertension.

====Echocardiography====

Echodoppler is the main diagnostic tool for recognizing pulmonic regurgitation. Regurgitant jet and velocity is visualized by Doppler. The width of the regurgitating jet can be used to quantify the severity. Diastolic regurgitation as well as early peak flow velocity in systole suggests the presence of pulmonary hypertension.  Echocardiography can reveal right ventricular hypertrophy and dilatation. Right ventricular volume overload is characterized by abnormal septal wall motion. Structural abnormalities of the pulmonic valve or congenital absence of the valve can be demonstrated by echocardiography.  

===Treatment===

The right ventricle normally adapts to low-pressure volume, high-pressure volume overload in contrast, ultimately leads to heart failure. Determining the underlying cause of pulmonic regurgitation and possible coexisting pulmonary hypertension is essential for appropriate therapy.  Treating the cause of pulmonary hypertension can relieve symptoms and decrease the severity of PR

If medical management is insufficient, surgical treatment options should be evaluated. The presence of severe right heart failure due to pulmonic regurgitation surgical pulmonic valve reconstruction or replacement can be considered.

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