Definitions and Morphology
Isolated congenital anomalies of the tricuspid valve (TV) are rare structural malformations that involve one or more components of the TV apparatus and result more commonly in tricuspid regurgitation (TR) and less often tricuspid stenosis (TS). The normal components of the TV include the annulus, three leaflets, chordae, and variable papillary muscle anatomy. When viewed from the ventricular aspect, the annulus is shaped like a reversed D and decreases in area by 30% during systole. The septal leaflet lies against the ventricular septum and is apically displaced in relation to the mitral annulus. The posterior leaflet, also known as the inferior leaflet, makes up the largest portion of the annulus and lies against the inferior wall of the right ventricle. The anterior (anterosuperior) leaflet is the largest and most mobile and extends anteriorly from the right ventricular infundibulum to the inferolateral wall. Each of the relatively small papillary muscles has chordal attachments to adjacent leaflets. A distinct feature of the TV, in comparison to the mitral valve, is its chordal attachments to the ventricular septum.
Tricuspid Stenosis
Isolated congenital malformations of the TV apparatus leading to TS are extremely rare. These include an underdeveloped annulus, shortened chordae, hypoplastic leaflets, underdeveloped fused commissures, parachute deformity (all the chordae arise from a single papillary muscle), and a supravalvular ring at the level of the annulus or midportion of the leaflets. In addition, abnormal persistence of the right venous valve can result in a double-chambered right atrium, also known as cor triatriatum dexter, a condition in which the proximal chamber receives all venous return and the distal chamber contains the TV ( Fig. 44.1 ). This perforated partition within the right atrium mimics the clinical presentation of TS.
Tricuspid Regurgitation
Tricuspid regurgitation in adults is most commonly functional in nature, related to right ventricular enlargement and/or dysfunction because of primary right ventricular (RV) myocardial disease, myocardial infarction (usually the right coronary artery), pulmonary hypertension, or left-sided heart diseases rather than as a result of a congenital deformity of the TV apparatus. Functional TR occurs because of the dilation of the tricuspid annulus and asymmetrical alterations of right ventricular geometry that lead to tethering of the TV leaflets and incomplete leaflet coaptation. On the other hand, the Ebstein anomaly (see Chapter 43 ) is the most common cause of congenital TR, followed by TV dysplasia, in which anatomic malformations can include hypoplastic papillary muscles, asymmetrically foreshortened tendinous chordae tethering the leaflets, and underdeveloped, atypical leaflets that prevent the valve from closing completely during systole ( Fig. 44.2A and B ). Partial or complete agenesis of the valvular tissue is often referred to as an unguarded tricuspid orifice. Both malformations have been associated with pulmonary stenosis and atresia (see Chapter 45 , Chapter 48 ). Other congenital anomalies leading to TR include (1) right-sided congenital partial absence of the pericardium, (2) papillary muscle rupture in the fetus or neonate, (3) the presence of bileaflet TV or cleft of the anterior leaflet (with or without atrial or ventricular septal defects), and (4) Uhl anomaly (best defined as aplasia or hypoplasia of the right ventricular myocardium, transforming it into a thin, passive, unexcitable conduit). The latter condition resembles arrhythmogenic right ventricular dysplasia/cardiomyopathy, in which the right ventricular myocardium is progressively replaced by adipose and fibrous tissue; this condition is often associated with ventricular arrhythmia and sudden death. Congenital deformities of the TV leading to TR can be mistaken for acquired diseases of the TV, including TV prolapse, endocarditis, TV involvement by rheumatic or carcinoid heart disease, or collagen vascular diseases. TR has also been reported after chest radiation, penetrating or blunt chest trauma, right ventricular endomyocardial biopsy, and endocardial lead placement because of leaflet entrapment, adhesion, or perforation or secondary to atrioventricular discordance with asynchronous ventricular pacing. In an observational study of 248 patients who had echocardiograms before and after placement of permanent pacemaker and implantable cardioverter defibrillator leads, TR worsened by at least 1 grade in 24.2%. Patients with an implantable cardioverter defibrillator had a higher rate of TR worsening compared with patients with a pacemaker (32.4% vs. 20.1%; p <.05). TR has also been seen in patients with chronic, and less often acute, atrial fibrillation resulting from related atrial and TV annulus remodeling. We have observed improved TR following restoration and maintenance of sinus rhythm. TR is also a known sequelae after surgical or device repair of ventricular septal defect resulting from fixation of the septal leaflet to the ventricular septum at the point where it was closed with a patch or device. Drugs such as cabergoline (a dopamine receptor-2 agonist used to treat prolactinomas), fenfluramine-phentermine, and ergotamine, which are serotonin-like or can potentiate the effect of circulating serotonin, can lead to valvular injury. In such injury the septal leaflet of the TV becomes thickened and variably fixed to the septum, whereas the anterior leaflet exhibits reduced mobility, resulting in loss of coaptation and TR, and to a lesser extent TS, and at times simulating carcinoid valvular disease. Drug-induced TV disease is often associated with other valve involvement, and in particular, the mitral valve. Furthermore, the use of gadolinium contrast during magnetic resonance imaging in patients with significant chronic kidney disease has been reported to infiltrate the TV causing TR, likely as part of nephrogenic systemic fibrosis. Irrespective of the cause of TR, severe TR is associated with adverse outcomes.
Genetics and Epidemiology
Little is known about the genetic predisposition to congenital TS and TR. In 1991 Sharland et al. reported that of 450 cases of structural heart disease diagnosed prenatally, 22 (4.9%) were of TV dysplasia and 16 (3.6%) were of Ebstein anomaly.
Review of the surgical pathologic analyses of 363 TVs excised and replaced at the Mayo Clinic between 1963 and 1987 demonstrated that 74% were purely regurgitant, 23% were stenotic and regurgitant, and only 2% were purely stenotic. Rheumatic disease was the most common cause (53%), followed by congenital disease (26%). Female patients accounted for 66% of all TVs excised. Male patients accounted for 61% of the congenital disorders, suggesting a male predominance. This study, however, included isolated TV anomalies and those associated with other congenital defects and excluded patients who had TV repair. A subgroup analysis of 45 patients with isolated TV defects showed that Ebstein anomaly was by far the most common (39 patients), followed by TV dysplasia (4 patients) and congenital TS (1 patient). Interestingly, the relative frequency of rheumatic disease decreased from 79% between 1963 and 1967 to 24% between 1983 and 1987. However, the frequency of all congenital TV anomalies requiring TV replacement increased from 7% to 53% during the same time interval.
Early Presentation and Management
Most isolated congenital TV anomalies, especially those leading to TS, present in infancy and childhood and require early intervention. In comparison, congenital TV anomalies resulting in TR can be tolerated for many years and may remain unrecognized until adulthood. Patients may be asymptomatic, and when symptoms begin, often include exertional fatigue or reduced exercise tolerance. If left untreated, symptoms may progress to severe heart failure with evidence of ascites, edema, and low forward stroke volume state with worsening resultant exertional fatigue, dyspnea, and cold extremities.
Although the initial mortality rates for TV replacement were as high as 30% to 50%, rates have improved to 7% to 17%. Rizzoli et al. reported a postoperative 50% 30-day mortality rate for patients of all age groups with congenital TV diseases. In most cases, death was related to low cardiac output. This high early mortality was due in part to late referral to surgery. The interest in repairing the regurgitant TV has increased more recently. The three basic reconstructive techniques are the Kay plication , in which the posterior (also known as inferior or mural) leaflet is plicated, converting the TV into a functionally bicuspid valve; the de Vega annuloplasty , which uses purse-string sutures to narrow the annulus along the anterior (anterosuperior) and posterior (inferior or mural) leaflets; and the ringed annuloplasty , in which a flexible or rigid ring is placed along the anterior and posterior aspects of the annulus. McElhinney et al. described the possible application of such a repair in children with TV dysplasia. He described two children with this anomaly, primarily with tethering of the septal leaflet because of abnormally short chordae, who underwent the operation at 9 and 11 years of age. The chordae that were tethering the septal leaflet were augmented by interposing appropriate lengths of expanded polytetrafluoroethylene suture and performing commissural annuloplasty. Each patient was reported to be asymptomatic 33 and 42 months after operation respectively. TR resulting from a cleft of the anterior leaflet can be repaired with simple suture and annuloplasty. For patients with Uhl anomaly, various surgical procedures have been performed, including Potts and bidirectional cavopulmonary anastomoses. None was successful in prolonging life. Cardiac transplantation and possibly the RV ventricular assist device appear to be the only options for these patients.
Late Outcome
Survival and Functional Status
When TR is acquired as a result of pulmonary hypertension, left-sided heart diseases, or primary cardiomyopathy, it may be a marker of worse prognosis because it reflects the severity of the underlying disease. Similarly, TR after heart transplantation has also been associated with increased risk of graft failure. However, because isolated congenital TS and TR (excluding Ebstein anomaly) are extremely rare, their natural history is not well defined. Depending on the severity of the TR, survival into adulthood is not uncommon for patients with conditions such as Uhl anomaly, cleft anterior TV leaflet, or acquired TR. Case reports documenting adults with other congenital deformities of the TV, including TV dysplasia, unguarded tricuspid orifice, and cor triatriatum dexter, have been published. The surgical results in these isolated cases are encouraging. However, there are a few reports that focus exclusively on late outcome after medical or surgical treatment of such conditions. Rizzoli et al. reported poorer postoperative survival for patients with congenital anomalies (22% survival rate at 5 years) than for the entire group (54% 5-year survival rate). Most survivors report considerable improvement in exercise tolerance after operation, and their New York Heart Association (NYHA) functional classification improved. With the refinement of surgical techniques and increased experience, improved outcome following TV surgery is expected.
Interestingly, although it had been suggested that biologic valves in the TV position have a lower rate of degeneration than valves in the mitral and aortic positions, this study demonstrated that survival did not significantly differ between patients with mechanical prostheses and those with biologic prostheses in the TV position—a reflection, perhaps, of the newer, low-profile mechanical valve with improved hemodynamics, low gradient, reduced turbulence, and a lower thrombosis rate. As a result of concerns about biologic valve thrombosis, especially in the early postoperative period, anticoagulation with warfarin should be considered especially in the early postoperative period and in patients with RV dysfunction and/or atrial fibrillation or in whom a cavopulmonary shunt was performed at the time of TV replacement.
Because TV annuloplasty is not commonly performed as an isolated procedure in patients with the rare forms of isolated congenital TV disease (other than Ebstein anomaly), its long-term results are poorly known. When TV annuloplasty is performed for functional TR, the freedom from important TV regurgitation is 94% at 10 years. However, this does not accurately reflect the experience of patients with congenital deformities of the TV. Data presented in Chapter 43 on Ebstein anomaly may be more relevant. Nevertheless, it is believed that intermediate and long-term survival and functional status of any patient having a TV operation are compromised by the preoperative presence of edema, pulmonary hypertension, and right ventricular dysfunction. Preoperative right ventricular dysfunction is commonly associated with worse outcome including heart failure and mortality. In patients with TR resulting from isolated flail TV, the severity of TR measured by the effective regurgitant orifice has been noted to herald worse prognosis. Late complications are summarized in Box 44.1 .
- •
Premature death as high as 19% for isolated tricuspid regurgitation (TR). Most related to advanced right ventricular dysfunction or arrhythmia. Rarely resulting from endocarditis or valve thrombosis. Risk factors include earlier date of operation, older age at operation, New York Heart Association (NYHA) functional class, and previous valve surgery.
- •
Complete heart block as high as 28% after tricuspid valve (TV) replacement in adults. Risk increases with concomitant mitral valve operation. Incidence is reduced by keeping sutures superficial.
- •
Valve thrombosis is rare in the absence of coagulation abnormalities. Incidence increases with age and is believed to have sharply decreased with the new, low-profile, bileaflet mechanical prosthesis.
- •
Thromboembolism including systemic (in association with an intraatrial shunt) and pulmonary embolism have rarely been reported (<1%).
- •
Prosthetic valve dysfunction can be subclinical, identified only on echocardiography.
- •
Anticoagulation-related hemorrhage increases with age but has declined as a result of increased awareness.
- •
Endocarditis of prosthetic valves carries a high risk, requiring periodic counseling and strict prophylaxis.
- •
Right ventricular failure is predominantly related to preoperative right ventricular dysfunction or myocardial preservation at operation. This is a major determinant of prognosis.
- •
Atrial arrhythmias are related to right atrial hypertension and enlargement or secondary to surgical scars.
- •
Ventricular arrhythmias are caused by right ventricular dysfunction or dysplasia.
- •
Recurrent TR after TV repair; more than moderate TR is noted in 0% to 12%, necessitating reoperation in 6%.
- •
Reoperation is predominantly because of operation early in life or to bioprosthetic valve degeneration; rarely a result of valve thrombosis; uncommon after repair (< 5%).
Outpatient Assessment
Unoperated Patients
Isolated congenital TS is rare and presents exclusively in infancy and childhood. Therefore whenever TS is suspected clinically or noted on echocardiography in an adult, it is usually the result of acquired heart disease, such as rheumatic or carcinoid heart disease, and less commonly the result of an indwelling central venous catheter or pacemaker wire. In addition, a primary or metastatic right atrial tumor, such as a myxoma (see Chapter 66 ), renal cell carcinoma, and even a right atrial thrombus, can mimic TS by obstructing the TV inflow and possibly precipitating syncope.
Patients with congenital anomalies of the TV or surrounding structures leading to TR can survive well into adulthood with minimal or no symptoms. The typical presentation of adults with TR includes dyspnea, exercise intolerance, palpitation, atrial fibrillation, and less often, heart failure. Some patients complain of cold feet and hands, likely because of reduced forward stroke volume. The presence of cyanosis, at rest or exercise, should alert one to the possibility of concomitant atrial shunt such as a patent foramen ovale or atrial septal defect with a secondary right-to-left shunt. Furthermore, the presence of severe edema, diarrhea, and/or hypoalbuminemia should alert one to the possibility of protein-losing enteropathy. Acquired diseases of the TV and right ventricle should always be considered when evaluating patients with TR. These include prolapse, endocarditis, trauma, irradiation, rheumatic or carcinoid heart disease, collagen vascular diseases, use of drugs such as fenfluramine-phentermine and ergotamine preparations, right ventricular dilation, right ventricular dysfunction, or pulmonary hypertension (functional TR). Many such conditions present similarly and thus can mimic congenital anomalies of the TV, including Ebstein anomaly (see Chapter 43 ). An adequate diagnostic evaluation includes the following:
- •
Careful history and physical examination to assess the severity of TR and to exclude the more common acquired causes of TR ( Box 44.2 )
BOX 44.2
- •
Patients are usually acyanotic unless there is a patent foramen ovale or (less commonly) an atrial septal defect. Under these circumstances the raised right atrial pressure related to tricuspid regurgitation (TR) generates a right-to-left shunt at the atrial level.
- •
Increased venous pressure with large v wave in the neck veins related to severe TR. However, at times the right atrium is so enlarged that it absorbs the regurgitant volume. Other signs of right-sided heart failure (edema, hepatomegaly) are not uncommon.
- •
Right ventricular heave is common secondary to right ventricular overload. However, the right ventricle is not palpable in patients with Uhl anomaly.
- •
Normal first heart sound. Split of the first heart sound is suggestive of Ebstein anomaly. Reduced heart sounds suggest Uhl anomaly.
- •
Normal or persistent split of the second heart sound. A loud pulmonary closure sound suggests pulmonary hypertension.
- •
Right ventricle third heart sound as a result of right ventricular dysfunction.
- •
Early systolic click and ejection murmur suggestive of pulmonary stenosis.
- •
Midsystolic click, mid to late systolic murmur suggestive of tricuspid valve (TV) or mitral valve prolapse.
- •
Systolic murmur of TR is typically diamond shaped if mild and holosystolic if severe in the left lower sternal border. It increases with inspiration. This distinguishes it from mitral regurgitation and ventricular septal defect. If the TR is very severe, the murmur may be brief or absent.
- •
Diastolic flow rumble if torrential TR or mixed TS and TR.
- •
Pulsating liver in severe TR.
Clinical Examination of Patients With Tricuspid Valve Regurgitation
- •
- •
Electrocardiography
- •
Chest radiography
- •
Transthoracic echocardiography ( Table 44.1 and Box 44.3 )
TABLE 44.1
Clinical and Echocardiographic Features of Common Non-Ebstein Anomaly Tricuspid Valve Abnormalities
TV Abnormalities
Clinical Findings
Echocardiographic Features
Rheumatic valvular disease
Rheumatic fever, MV involvement
Focal chordal thickening, diffuse fibrous thickening, diffuse marginal or leaflet thickening of the MV or TV, commissural fusions
Tricuspid valve prolapse
Mitral valve prolapse (5% to 52% of patients), especially in older women (F:M ratio 3:1); aortic valve prolapse (rare); dilated cardiomyopathy; pulmonary hypertension; hypertensive heart disease; pectus deformity, scoliosis, and straight-back syndrome on chest radiography
Myxomatous degeneration of the TV or MV, with prolapse of one or more leaflets beyond the annular ring (parasternal or apical view); elongated, redundant chordae; large leaflets; TV annular dilation
TV endocarditis
Pneumonia, use of intravenous drugs, habitual alcoholism, immunodeficiency state
TV vegetations, ruptured chordae, valvular indentation
Traumatic TR
Chest trauma, nonpenetrating within 1 month to 37 years; indwelling catheter, wire, etc.
Ruptured TV tensor apparatus (chordae, papillary muscle), leaflet perforation
RV dysplasia, Uhl anomaly
Ventricular tachycardia (in RV dysplasia), family history (in RV dysplasia), reduced intensity of heart sounds, low QRS amplitude on electrocardiography
RV free wall aneurysm, focal RV thinning, RV dysfunction, abnormal septal motion
Tricuspid annular dilation
RV infarction, pulmonary hypertension (any cause), cardiomyopathy, chronic atrial fibrillation (in the elderly)
TV annular dilation, RV or LV enlargement and dysfunction, biatrial enlargement
TV dysplasia, unguarded
Remote history of heart murmur, pulmonary stenosis
Hypoplastic, diminutive, or absent leaflets; tricuspid orifice underdeveloped, small papillary muscle; shortened chordae with tethering
Carcinoid heart disease
Gastrointestinal hypermotility; bronchospasm, flushing; pulmonary valve involvement
Thickened margins, chordae; retracted, tethered leaflets; endocardial carcinoid plaques on TV or in RV; pulmonary valve involvement
Other: connective tissue disease, radiation therapy, ergotism or use of diet drugs
History of lupus or rheumatoid arthritis; previous chest irradiation; or history of intake of ergot alkaloid preparations or anorexigens (eg, fenfluramine-phentermine)
Leaflet contraction, thickening; shortened chordae; or aortic valve or MV involvement 
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
