Approach
Clinically significant tricuspid stenosis (TS) can be suspected based on a history of acute rheumatic fever (ARF) as a child, presenting symptoms (fatigue, extremity swelling, fluttering neck discomfort, abdominal discomfort, or dyspnea), and on classic physical examination findings.[27] However, further studies such as ECG, echocardiogram, and cardiac catheterization are typically used to confirm the diagnosis. By far the most common presentation is as a late result of a single severe case or, multiple recurrent episodes of ARF and typically occurs anywhere from 16 to 40 years after initial group A streptococcus (GAS) exposure.[28]
History
Although the age range can vary, patients usually present at ages 20-39 years.[6] Most patients with symptomatic TS will present with fatigue, extremity swelling, fluttering neck discomfort, abdominal discomfort, or dyspnea that is slowly progressive over a period of months to years. The fatigue usually relates to some degree of limited cardiac output. The dyspnea usually results from concomitant rheumatic mitral stenosis, and is usually more pronounced when attempting exercise. The other symptoms relate to systemic venous congestion causing hepatomegaly, elevated jugular venous pressure (JVP), ascites, and edema.
A critical piece of information to acquire is whether or not there is an antecedent history of ARF. Many adult patients may not have been informed of their actual diagnosis during childhood or the disease may have never been discovered. These patients may only remember an illness with a prolonged fever, rash, or severe joint pain. Similarly, the patient may only remember having had to endure a prolonged period of bed rest and being away from school. A history of persistent heart murmur beginning in late childhood that has been passed-off as benign or innocent may also be the only historical clue to antecedent episode of ARF. If a history of ARF is denied or unknown, these historical items should be sought out specifically.
Features of flushing, diarrhea, and bronchospasm should raise the possibility of carcinoid syndrome, and these patients have a 50% chance of cardiac involvement. The vast majority of patients with cardiac involvement present with signs of right heart failure secondary to severe dysfunction of the tricuspid and pulmonary valves.
Patients may present with unremitting or recurrent fever with generalized malaise and other physical stigmata of bacterial endocarditis. The patient may have an antecedent history of tricuspid valve replacement or intravenous drug use.
Congenital stenosis usually presents in infancy or at an early age with symptoms of right heart failure and cyanosis and is often associated with other structural heart defects.
Physical examination
The patient's vital signs are often normal. Jugular venous pulsations are often elevated and a prominent presystolic a-wave during atrial contraction is considered to be a classic finding. However, in the presence of atrial fibrillation (patients with rheumatic TS may present with atrial fibrillation) when atrial systole is lost, this classic finding is absent, resulting in a lower index of suspicion for TS.
Hepatomegaly, ascites, and peripheral edema are often observed in patients with moderate to severe TS.
Focused cardiac examination reveals cardinal signs of TS. The precordium is usually quiet without a right ventricular lift or heave. A soft, low-frequency presystolic murmur can usually be auscultated at the lower left sternal border in the fourth intercostal space. The murmur can be intensified with maneuvers that increase blood flow across the valve (e.g., inspiration, squatting, and isotonic exercise). An opening snap can sometimes be heard, but is often confused with the opening snap of a stenotic mitral valve, which is also often present. Similarly, the presystolic murmur of TS is often missed or attributed to mitral valve stenosis. Although there are characteristics of the two murmurs that can help differentiate one from the other, a high index of suspicion must be maintained for tricuspid valve involvement in a patient with polyvalvular rheumatic heart disease (RHD).
Patients with endocarditis-associated TS will present with the same physical findings discussed above, occasionally with the physical stigmata of bacterial endocarditis (e.g., splinter hemorrhages, Osler nodes, and Janeway lesions).
Hypoxemia predominates with congenital TS secondary to right-to-left atrial level shunting.
There are no specific physical examination findings in patients with carcinoid heart disease that distinguish it from other forms of TS.
Laboratory evaluation
CBC and blood cultures should be used to evaluate for bacterial endocarditis. Comprehensive metabolic profile should be obtained to evaluate for significant hepatic congestion associated with systemic venous hypertension and as a general estimate of end-organ dysfunction (e.g., renal insufficiency). If carcinoid heart disease is suspected, 24-hour urinary excretion of 5-hydroxy-indole acetic acid (5-HIAA) may be used to determine whether it is present.
Specialist referral, ECG, and imaging
If a patient presents to a physician with a history concerning for ARF and many of the signs and symptoms described, it is appropriate to refer the patient to a cardiologist for further evaluation. The cardiology evaluation is likely to include repeat physical examination, chest x-ray, ECG, echocardiogram, and possibly referral for cardiac catheterization. Echocardiogram should be performed at the time the diagnosis is being considered; in general this is performed and interpreted by a specialist. Initial echocardiogram is usually transthoracic (2D or Doppler); however, transesophageal or 3D studies may be necessary if adequate images cannot be obtained. This includes cardiac MRI, which can help delineate tricuspid valve morphology and function as well as evaluate for underlying causes of tricuspid stenosis or better characterize the hemodynamic impact of tricuspid stenosis (e.g., right atrial dilation).[29]
Although there are no clearly defined criteria in the literature for TS severity, severe TS is usually defined by the onset of overt symptoms accompanied by a mean gradient by echocardiogram or cardiac catheterization of ≥5 mmHg or >7 to 10 mmHg depending on the method and definition.[30][31][32][33] Mild to moderate TS is usually asymptomatic, and has no clearly defined gradient range beyond the definition of TS diagnosed on a gradient of ≥2 mmHg. [Figure caption and citation for the preceding image starts]: Hemodynamic tracings obtained during cardiac catheterization from a woman with moderate to severe rheumatic tricuspid valve stenosisFrom the personal collection of Martin Bocks; used with permission [Citation ends].
Cardiac MRI may be useful in identifying valve abnormalities in carcinoid heart disease and reliably detecting progressive dilatation and right ventricle dysfunction.[34][35][36]
Other imaging to consider includes cardiac computed tomography angiography (CTA) and [18F] fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), particularly to detect valvular lesions and confirm endocarditis in cases where echocardiography has been inconclusive.[2]
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