Disclosure
Background: Tricuspid valve disease involves the atrioventricular valve apparatus that separates the right atrium (RA) from the right ventricle (RV). Tricuspid regurgitation (TR) and tricuspid stenosis (TS) are commonly encountered. Isolated tricuspid valve disease is rare. It most often occurs as a secondary condition. TR is more common than TS and usually develops in association with pulmonary hypertension in patients with mitral stenosis or regurgitation. Most patients with rheumatic tricuspid valve disease present with TR or a combination of stenosis and regurgitation. Rheumatic TS does not occur as an isolated lesion, but it often accompanies mitral and aortic valve disease. Some patients may develop TR because of trauma or infective endocarditis. TS is nearly always rheumatic in origin. However, congenital tricuspid atresia, RA tumors, obstruction of RV inflow due to endomyocardial fibrosis in carcinoid syndrome, tricuspid valve vegetations, presence of a pacemaker lead, or compression due to extracardiac tumors may also produce a clinical picture similar to that of TS. Echocardiography provides excellent images and can be used to detect and quantitate tricuspid regurgitation. It also permits assessment of the dimensions of cardiac chambers, determination of RV and pulmonary pressures, and delineation of associated valvular diseases. Pathophysiology: In most patients with TR, RA and RV pressures are increased. The RA pressure tracing usually reveals an augmented a wave, absence of x descent, and a prominent v or c-v wave. These findings may not be discernible in mild TR, but they are always present in moderate or severe TR. As the severity of TR increases, the shape of the RA pressure pulse begins to resemble the RV pressure pulse. The usual decrease in RA pressure on deep inspiration is not seen; rather, a paradoxical increase may be noted. Measurement and analysis of the pulmonary arterial or RV systolic pressure may indicate whether the TR is primarily due to disease of the valve or secondary to RV dilatation. A pulmonary arterial or RV systolic pressure less than 40 mm Hg suggests a primary cause, whereas a pressure greater than 55 mm Hg suggests that TR is secondary. Frequency:
Mortality/Morbidity: Most patients with tricuspid valve disease remain asymptomatic for many years.
Race: No particular racial predilection is observed, though endomyocardial fibrosis with shortening of the tricuspid leaflets and chordae tendineae is an important cause of TR in tropical Africa. Sex: TS is more common in women than in men. Age:
Anatomy: Tricuspid stenosis TS involves commissural fusion of the valve cusps along with fusion and shrinkage of the chordae tendineae similar to rheumatic mitral stenosis. When the valve opens, it resembles a tentlike structure with a fixed central opening. Valvular calcification is rare. The RA develops pressure overload and tends to become thick walled and dilated. The pressure overload leads to further passive congestion, causing enlargement of the liver and spleen. A small rise in the transvalvular pressure gradient, such as a gradient of 5 mm Hg, can usually augment the mean RA pressure enough to cause systemic venous congestion. Jugular venous distention, ascites, and edema develop as a result. In patients with a sinus rhythm, the a wave of the RA may be tall, and it may increase to the level of the RV systolic pressure. Resting cardiac output is decreased and it shows an absence of augmentation on exercise. The mean diastolic pressure gradient across the tricuspid valve may be as low as 2 mm Hg, and it may be enough to consider the diagnosis of TS. Increase in the gradient is seen with exercise, deep inspiration, rapid fluid infusion, or intravenous atropine. TS is rheumatic in origin in most instances. Unusual causes include congenital tricuspid atresia; right atrial tumors, which may produce a clinical picture suggesting rapidly progressive TS; carcinoid syndrome, which more frequently produces tricuspid regurgitation; and obstruction to right ventricular inflow due to endomyocardial fibrosis, tricuspid valve vegetations, a pacemaker lead, or compression due to extracardiac tumors. Marfan syndrome usually causes aortic regurgitation. It may cause tricuspid regurgitation, but it does not cause TS. Tricuspid regurgitation TR is usually secondary to increased pulmonary pressures and mitral valve disease. A systolic RV pressure of 55 mm Hg can cause functional TR. Other causes include RV infarction, pulmonic stenosis, primary pulmonary hypertension, and cor pulmonale. TR can also occur as a consequence of dilatation of the annulus in Marfan syndrome. Functional TR may decrease or disappear as the RV decreases in size in the treatment of heart failure with diuretics. Primary TR can occur as part of an Ebstein anomaly, with an atrioventricular canal defect or corrected transposition of the great arteries, and occasionally with aneurysm of the ventricular septum. Rheumatic fever may directly involve the tricuspid valve by causing scarring of the valve leaflets and chordae tendineae, leading to limited leaflet mobility and either isolated TR or a combination of TR and TS. Tricuspid involvement is almost always associated with rheumatic involvement of the mitral values and, often, the aortic valves. In carcinoid syndrome, focal or diffuse deposits of fibrous tissue on the endocardium of the valve leaflets may cause TR or the combination of TR and TS. The white, fibrous carcinoid plaques are most extensive on the right side of the heart, where they are usually deposited on the ventricular surfaces of the tricuspid valve. Endomyocardial fibrosis is sometimes a cause of TR in tropical Africa. It causes shortening of the tricuspid leaflets and the chordae tendineae. TR can also be a result of tricuspid valve prolapse caused by myxomatous changes in the valve and chordae tendineae. It is usually coexistent with the prolapse of the mitral valve. Tricuspid valve prolapse is seen in about 20% of all patients with mitral valve prolapse. It is sometimes associated with an atrial septal defect. Other causes of TR include penetrating and nonpenetrating trauma, dilated cardiomyopathy, infective endocarditis (particularly staphylococcal endocarditis in narcotics addicts), and surgical excision of the tricuspid valve in patients with infective endocarditis that is unresponsive to medical management. Less common causes of TR include cardiac tumors (particularly RA myxoma), transvenous pacemaker leads, repeated endomyocardial biopsy in a transplanted heart, endomyocardial fibrosis, methysergide-induced valvular disease, the administration of fenfluramine-phentermine, and systemic lupus erythematosus involving the tricuspid valve. Clinical Details: Tricuspid stenosisHistory The patient's clinical history includes progressive fatigue, edema, anorexia, and history of rheumatic fever (two thirds of patients). TS has a female preponderance. Orthopnea, paroxysmal nocturnal dyspnea, pulmonary edema, and hemoptysis are rare. Physical examination Physical findings may include wasting, peripheral cyanosis, and distention of the neck veins with prominent v waves. Other findings include hepatic pulsation, ascites, and peripheral edema. On palpation, RV lift can be appreciated over the precordium. On auscultation, TR manifests as a holosystolic murmur, which is maximal at the lower left sternal border and which is accentuated with inspiration. A diastolic rumble may be audible in some patients at the lower left sternal border, which increases in intensity with inspiration. Diagnostic studies ECG shows tall RA P waves and no RV hypertrophy. Chest radiography shows a dilated RA without an enlarged pulmonary-artery segment. Tricuspid regurgitationHistory Patients generally remain asymptomatic in the absence of pulmonary hypertension. After pulmonary hypertension develops, cardiac output declines, and the manifestations of right-sided heart failure become apparent. Symptoms include dyspnea on exertion, fatigue, and, in late stages, edema and abdominal swelling and pain. Patients occasionally have throbbing pulsations in the neck, which increase on effort and are due to jugular venous distention. Systolic pulsations of the eye orbits may be seen. Physical examination On inspection, signs include evidence of weight loss and cachexia. Cyanosis and jaundice are often observed in patients with severe TR. When patients present with palpitations, atrial fibrillation is noted to be present on the ECG. A venous systolic thrill and murmur in the neck may be present in patients with severe TR. The jugular venous pressure is elevated. Normal x and x' descents disappear, and a prominent systolic v wave (also called a c-v wave or an s wave) can be appreciated. The y descent is characteristically sharp. On palpation, the RV impulse is hyperdynamic and may be thrusting in quality. Systolic pulsations of an enlarged, tender liver may be present initially. Ascites and edema are frequently associated findings. As liver cirrhosis develops, the hepatic enlargement recedes. On auscultation, the systolic murmur of TR is high pitched and occupies the entire systole. It is most prominent in the fourth intercostal space in the left parasternal region. In patients with mild TR, the murmur may be short. When TR occurs in the absence of pulmonary hypertension, such as in infective endocarditis or trauma, the murmur is usually of low intensity and early systolic. A right-sided S3 may be present that represents RV enlargement and dysfunction. In patients with pulmonary hypertension, P2 becomes louder. The TR murmur is characteristically augmented in the following conditions: (1) with the Carvallo sign (The TR murmur is enhanced during inspiration. As RV becomes dysfunctional, the inspiratory augmentation may still be elicited by having the patient stand up from a recumbent position.), (2) with the Mueller maneuver (The murmur also increases during the forced inspiration against a closed glottis.), (3) with exercise, (4) with leg raising, and (5) with direct hepatic compression. Tricuspid valve prolapse, like mitral valve prolapse, may cause a midsystolic click and a late systolic murmur. The murmur is most prominent at the lower left sternal border. With inspiration, the click is delayed, whereas the murmur becomes louder and shortens. Diagnostic studies ECG findings are frequently nonspecific. Incomplete right bundle-branch block, Q waves in lead V1, and atrial fibrillation are often noted. Preferred Examination: Echocardiography is the preferred examination. Tricuspid stenosis The echocardiographic changes of the tricuspid valve in TS include diastolic doming of the valve, thickening and restricted motion of the leaflets, reduced separation of the commissures of the leaflets, and a diminished tricuspid opening. Transesophageal echocardiography improves depiction of the details of valvular structure. Doppler echocardiography shows a delayed slope of antegrade flow that compares well with cardiac catheterization findings in the quantification of TS and in the assessment of associated TR. Tricuspid regurgitation The main purpose of echocardiographic imaging is to diagnose TR, assess its severity, and estimate pulmonary arterial pressure and the status of RV function. In secondary TR, clinically significant enlargement of the tricuspid annulus, RA, and RV are found. In patients with TR due to endocarditis, echocardiography may reveal vegetations on the valve or a flail valve leaflet. Transesophageal echocardiography can depict the TR vividly. Limitations of Techniques: If acoustic windows are poor, transthoracic echocardiograms may be suboptimal. In such instances, transesophageal echocardiography is helpful.
Carcinoid, Gastrointestinal
Findings: In TS, radiographs may show marked cardiomegaly with conspicuous enlargement of the RA (ie, prominence of the right heart border), which extends into a dilated superior vena cava and azygos vein, but conspicuous dilatation of the pulmonary artery may be absent. Vascular changes in the lungs characteristic of mitral valvular disease may be masked, with little or no interstitial edema or vascular redistribution; however, left atrial enlargement may be present. In patients with functional TR, marked cardiomegaly is usually evident, and the RA is prominent. Evidence of elevated RA pressure may include distention of the azygos vein and the presence of a pleural effusion. Ascites with upward displacement of the diaphragm may be present. Systolic pulsations of the RA may be present on fluoroscopy. Degree of Confidence: Findings are generally nonspecific. False Positives/Negatives: False findings are frequent. |
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Findings: CT scans of the heart are rarely needed to delineate structural cardiac abnormalities. Degree of Confidence: The degree of confidence is moderate. False Positives/Negatives: The rate of false findings is low.
Findings: MRI may be helpful in delineating valvular structural abnormalities when echocardiographic assessment is suboptimal. In patients with tricuspid regurgitation, spin-echo (SE) and cine gradient-echo (GRE) imaging can provide important data. SE imaging The major hemodynamic effect of TR is augmentation of the total stroke volume of the RV. SE MRIs can display the RV myocardium well. SE MRI may be the preferred technique for accurate assessment of RV function, such as measurement of RV end-diastolic, end-systolic, and stroke volumes, as well as the ejection fraction. When the RV wall is thickened and hypokinetic, particularly with ventricular arrhythmias or syncope, MRI can be used to look for RV dysplasia (transdifferentiation of myocardium to fat). In addition to the RV, SE MRI can show enlargement of the RA, vena cava, and hepatic veins. Cine GRE imaging Cine GRE images are used to determine the severity of TR by demonstrating the area of the signal void of the regurgitant jet traveling into the RA in systole. It is best imaged in the 4-chamber view and the coronal oblique view displaying the RA and the RV. Velocity-encoded imaging Similar to Doppler echocardiography, velocity-encoded (VENC) MRI permits assessment of the severity of regurgitation by determining the maximum velocity (Vmax) in the regurgitant jet with velocity measurements in a plane parallel to the jet (in-plane measurement). The velocity measurement can then be used to calculate pulmonary arterial systolic pressure (PPA) by adding RA pressure (PRA which is empirically taken as 10 mm Hg) to the RV and RA pressure gradient (P) For this purpose, the following modified Bernoulli equation is used PPA = 10 + (4 X Vmax2) Miscellaneous SE images can show other structural abnormalities, including Ebstein anomaly, pacemaker leads, valvular vegetations, tricuspid prolapse, and carcinoid syndrome. Degree of Confidence: The degree of confidence is high. False Positives/Negatives: The rate of false findings is low. While performing cine GRE imaging, one must remember to keep the echo time somewhat long, as short echo times may not help in showing the signal void well.
Findings: Tricuspid stenosis The echocardiographic changes of the tricuspid valve in TS resemble those observed in the mitral valve in mitral stenosis. Two-dimensional echocardiography characteristically shows diastolic doming of the leaflets (especially the anterior tricuspid valve leaflet), thickening and restricted motion of the other leaflets, reduced separation of the tips of the leaflets, and a reduction in diameter of the tricuspid orifice. Transesophageal echocardiography added details of the valvular structure. Doppler echocardiography shows a prolonged slope of antegrade flow and compares well with cardiac catheterization in the quantification of TS and in the assessment of associated TR. Tricuspid regurgitation The goal of echocardiography is to detect TR, estimate its severity, and assess pulmonary arterial pressure and RV function. In patients with TR secondary to dilation of the tricuspid annulus, the RA, RV, and tricuspid annulus are usually greatly dilated on echocardiography. Evidence suggests RV diastolic overload with paradoxical motion of the ventricular septum similar to that observed in atrial septal defect. Exaggerated motion and delayed closure of the tricuspid valve are evident in patients with Ebstein anomaly. Prolapse of the tricuspid valve due to myxomatous degeneration may be evident on echocardiography. Echocardiographic indications of tricuspid valve abnormalities, especially TR shown on Doppler examination, can be detected in most patients with carcinoid heart disease. In patients with TR due to endocarditis, echocardiography may reveal vegetations on the valve or a flail valve. Transesophageal echocardiography enhances the detection of TR. Contrast echocardiography involves rapid injection of saline indocyanine green dye or sonicated human albumin (Albunex) into an antecubital vein while a 2-dimensional echocardiogram is recorded. The injection produces microcavities that are readily visible on echocardiography and normally travel as a bolus through the circulation. In TR, these microcavities can be seen to travel back and forth across the tricuspid orifice and to pass into the inferior vena cava and hepatic veins during systole. Pulsed Doppler echocardiography reveals systolic flow from the RV to the RA and is a sensitive technique for detecting and quantifying TR. Reverse flow can also be recorded in the inferior vena cava and hepatic veins. The peak velocity of TR flow is useful in the noninvasive estimation of RV (and pulmonary arterial) systolic pressure. Color flow Doppler imaging is a sensitive and specific method for assessing TR and helpful in selecting patients for surgical treatment and in evaluating postoperative results. Degree of Confidence: The degree of confidence is high. False Positives/Negatives: False findings are rare.
Findings: Patients who present with congestive heart failure may require tricuspid valve function as well as LV function assessed by using a first-pass technique (multiple-gated acquisition [MUGA] scanning). Degree of Confidence: The degree of confidence is moderate. False Positives/Negatives: Findings may be nonspecific.
Findings: Tricuspid stenosis Angiography performed after the injection of contrast material into the RA and imaging in the 30° right anterior oblique projection characteristically shows thickening and decreased mobility of the leaflets, a diastolic jet through the constricted orifice, and thickening of the normal atrial wall. Tricuspid regurgitation In patients with TR, RA and RV end-diastolic pressures are often elevated in TR, whether the condition is due to organic disease of the tricuspid valve or is secondary to RV systolic overload. The RA pressure tracing usually reveals absence of the x descent and a prominent v or c-v wave (ventricularization of the atrial pressure). Absence of these findings essentially excludes moderate or severe TR. As the severity of TR increases, the contour of the RA pressure pulse increasingly resembles that of the RV pressure pulse. An increase or no change in RA pressure on deep inspiration, rather than the usual decrease, is a characteristic finding. Determination of the pulmonary arterial (or RV) systolic pressure may be helpful in deciding whether the TR is primary (ie, due to disease of the valve or its supporting structures) or functional (ie, secondary to RV dilatation). A pulmonary arterial or RV systolic pressure less than 40 mm Hg suggests a primary cause, whereas a pressure greater than 55 mm Hg suggests that TR is secondary. Intermediate values are not helpful. In many instances, right ventriculography may aid the diagnosis and quantitative assessment of TR. Degree of Confidence: The degree of confidence is high. False Positives/Negatives: False findings are rare.
Intervention: Tricuspid stenosis Although the fundamental approach to the management of severe TS is interventional or surgical treatment, intensive sodium restriction and diuretic therapy may diminish symptoms secondary to the accumulation of excess salt and water. Preparatory diuresis may diminish hepatic congestion and thereby sufficiently improve hepatic function to diminish the risks of the subsequent operation. Most patients with TS have coexisting valvular disease that requires surgery. In patients with combined TS and mitral stenosis, the former must not be corrected alone because pulmonary congestion or edema may ensue. The final decision concerning surgical treatment is often made at the operating table. The feasibility of tricuspid balloon valvuloplasty has been demonstrated, and this procedure may be combined with mitral balloon valvuloplasty. Valvuloplasty or surgical treatment of TS should be performed at the time of mitral valve repair or replacement in patients with TS in whom the mean diastolic pressure gradient exceeds 5 mm Hg and in whom the tricuspid orifice is less than approximately 2.0 cm2. Because TS is almost always accompanied by TR, simple finger fracture valvotomy may not result in significant hemodynamic improvement; it may merely substitute severe regurgitation for stenosis. However, open valvotomy may result in substantial improvement because the stenotic tricuspid valve is converted into a functionally bicuspid valve. The commissures between the anterior and septal leaflets and between the posterior and septal leaflets are opened. Opening the commissure between the anterior and posterior leaflets is not advised because severe regurgitation may result. If open valvotomy does not restore reasonably normal valve function in patients with TS, the tricuspid valve may have to be replaced. A large porcine bioprosthesis is preferred to a mechanical prosthesis in the tricuspid position because of the high risk of thrombosis with the latter and because of the prolonged durability of bioprostheses in the tricuspid position rather than in the mitral or aortic positions. Tricuspid regurgitation At the time of mitral valve surgery in patients with TR secondary to pulmonary hypertension, the severity of the regurgitation should be assessed by palpation of the tricuspid valve. In addition, whether the TR is secondary to pulmonary hypertension, in which case the valve is normal, or whether it is secondary to rheumatic fever should be determined. In the absence of pulmonary hypertension, TR is usually well tolerated, and surgical treatment may not be required. Indeed, both human patients and experimental animals with a normal pulmonary arterial pressure may tolerate total excision of the tricuspid valve as long as the RV systolic pressure is normal. Dilatation of the right side of the heart usually occurs months or years after tricuspid valvectomy (which is usually performed to treat acute infective endocarditis). Patients with mild TR usually do not require surgical treatment; pulmonary vascular pressures decline after successful mitral valve surgery in rheumatic cases with mitral stenosis and TR, and the mild TR tends to disappear. In patients with moderate TR, excellent results are reported with suture annuloplasty of the posterior (unsupported) portion of the annulus. Patients with severe TR and primary rheumatic tricuspid valve disease with commissural fusion require valvotomy and ring annuloplasty. The latter is also used for TR secondary to annular dilatation. A surgical mortality rate of 13.9% is reported. If procedures described do not provide a good functional result at the operating table (as assessed with transesophageal echocardiography), valve replacement with a large porcine mitral heterograft may be required. In TR, surgical treatment of acquired regurgitation secondary to annular dilatation was greatly improved when Carpentier introduced the concept of suturing the annulus to a prosthetic ring. Annuloplasty without insertion of a prosthetic ring (DeVega annuloplasty) was effective in patients with annular dilatation. This technique is now widely used. Medical/Legal Pitfalls:
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