Tricuspid Regurgitation

TR represents backflow of blood from the RV to RA typically occurring during systole, but in rare conditions (atrioventricular block, atrial flutter, restrictive cardiomyopathy, etc.) it may also occur during diastole. (EACVI Textbook of Echocardiography)

TR is a relatively frequent finding in adult patients. Trivial or mild functional TR without any detectable abnormality of the TV is seen in 65–75% of healthy subjects and is considered benign, while significant functional TR is associated with poor prognosis. (EACVI Textbook of Echocardiography)

With a meticulous search for valve regurgitation, MR can be detected in 70% to 80%, tricuspid regurgitation in 80% to 90%, and pulmonic regurgitation in 70% to 80% of normal individuals. This small degree of regurgitation is normal and has no adverse clinical implications. (Otto, Clinical Echocardiography 6e)

Tricuspid regurgitation occurs with abnormalities of the supporting structures (annulus, RV) or the leaflets themselves. (Otto, Clinical Echocardiography 6e)

The aetiology of TR is generally divided into primary (or organic, having intrinsic structural changes of TV leaflets) and secondary (or functional, no structural leaflet abnormalities). (EACVI Textbook of Echocardiography)

Primary TR represents only a minority of severe TR (8–10%), and is due to various aetiologies. (EACVI Textbook of Echocardiography)

Secondary TR is the predominant mechanism of TR, developing as consequence of deformation of the TV apparatus, such as TA enlargement with abnormal shape, and increased leaflet tethering related to RV dilatation with papillary muscle displacement. (EACVI Textbook of Echocardiography)

Common conditions evolving with functional TR are left-sided heart valve diseases, pulmonary hypertension, congenital heart defects (e.g. atrial septal defects), atrial fibrillation, and cardiomyopathies. (EACVI Textbook of Echocardiography)

The pathophysiology of functional TR is rather complex and starts as a vicious circle in which regurgitation leads to further RV dilation, which increases TA dilation, leaflet tethering, and, as a result, more TR. (EACVI Textbook of Echocardiography)

Tricuspid regurgitation secondary to annular dilation often is due either to primary RV dilation and systolic dysfunction or to pulmonary hypertension. (Otto, Clinical Echocardiography 6e)

Abnormalities of the tricuspid valve leaflets also are a cause of tricuspid regurgitation. Rheumatic disease involves the tricuspid valve in approximately 20% to 30% of cases, nearly always occurring in conjunction with mitral and aortic valve involvement. (Otto, Clinical Echocardiography 6e)

Carcinoid heart disease (seen with metastatic carcinoid tumor to the liver) is characterized by thickened, shortened, and immobile tricuspid valve leaflets with resultant tricuspid regurgitation or, less often, tricuspid valve stenosis. (Otto, Clinical Echocardiography 6e)

Endocarditis may involve the tricuspid valve, which results in tricuspid regurgitation, and is most common in patients with a history of intravenous drug abuse. (Otto, Clinical Echocardiography 6e)

Ebstein anomaly of the tricuspid valve is a congenital abnormality in which one or more leaflets of the tricuspid valve are displaced from the tricuspid annulus toward the ventricular apex. (Otto, Clinical Echocardiography 6e)

Myxomatous disease: causes TV prolapse, most commonly accompanying mitral valve prolapse/flail, but occasionally found isolated as well. (EACVI Textbook of Echocardiography)

Trauma: blunt chest trauma (e.g. after car or motor vehicle accident, sports injury, or falling from a height) is the most common cause of chordal or papillary muscle rupture. Anterior leaflet is most frequently involved. (EACVI Textbook of Echocardiography)

Drugs: ergotamine, cabergoline, pergolide, fenfluramine, and benfluorex are among the most commonly cited valvulopathic drugs, causing abnormal thickening of valve leaflets, resulting in a restrictive motion, thickening, and shortening of the chordae tendineae and leaflet tethering with mal-coaptation. (EACVI Textbook of Echocardiography)

Hemodynamically significant tricuspid regurgitation results in progressive RV and RA enlargement due to volume overload. This dilation complicates an assessment of the cause of regurgitation because the dilation itself further increases regurgitant severity. (Otto, Clinical Echocardiography 6e)

RV volume overload is associated with a pattern of abnormal septal motion characterized on M-mode recording by posterior motion of the septum in diastole (because RV filling exceeds LV filling) and anterior motion of the septum in systole, often referred to as paradoxical septal motion. (Otto, Clinical Echocardiography 6e)

Severe tricuspid regurgitation results in systolic flow reversal in the inferior and superior vena cavae, analogous to the physical finding of a systolic pulsation in the neck veins. (Otto, Clinical Echocardiography 6e)

Although well tolerated, severe long-standing TR leads to progressive RV systolic dysfunction and irreversible myocardial damage. (EACVI Textbook of Echocardiography)

Severe chronic TR is commonly associated with RV, RA, and IVC dilation. (EACVI Textbook of Echocardiography)

Work through it in a logical order: define the valve anatomy and the mechanism of regurgitation, build severity from qualitative to quantitative measures, assess the secondary effects on the right ventricle, right atrium, inferior vena cava and pulmonary pressures, then integrate with the clinical picture — always distinguishing primary from secondary disease (and atrial from ventricular functional TR), and acute from chronic.

Useful views for evaluating tricuspid regurgitation include a parasternal short-axis view, the RV inflow view, and the apical four-chamber view. (Otto, Clinical Echocardiography 6e)

Mild to moderate tricuspid regurgitation often is directed along the interatrial septum and must be distinguished from normal caval inflow or from atrial septal defect flow. (Otto, Clinical Echocardiography 6e)

Parasternal short-axis view at aortic valve level: the leaflet adjacent to RV free wall is the posterior leaflet, while the leaflet adjacent to aortic valve can be anterior or, less frequent, septal. (EACVI Textbook of Echocardiography)

Apical RV-focused four-chamber view: the leaflet adjacent to the septum is the septal leaflet, while the leaflet adjacent to the RV free wall is anterior or posterior. (EACVI Textbook of Echocardiography)

A modified TV-focused view can be obtained by moving the transducer from the standard four-chamber view in a higher intercostal space, medially (closer to the sternum and TV), and orientating it almost perpendicular to the skin. In this view the RV will be foreshortened, but TV leaflets and TR jet origin can be better visualized, allowing continuous wave (CW) Doppler sampling even with trivial TR. (EACVI Textbook of Echocardiography)

The Carpentier's classification is the most commonly used functional classification in TR: Type I: normal leaflet motion (annular dilatation; leaflet perforation in infective endocarditis); Type II: excessive leaflet motion (prolapse of one or more leaflets); Type III: restricted leaflet motion (rheumatic disease, carcinoid disease, toxic valvulopathy, excessive tethering in functional TR). (EACVI Textbook of Echocardiography)

Conventionally, a significant TA dilation by 2DE is defined by a diastolic TA diameter in four-chamber view of 40 mm or more, or greater than 21 mm/m2. Significant leaflet tethering is suggested by a coaptation distance bigger than 8 mm in four-chamber view in mid-systole. (EACVI Textbook of Echocardiography)

Meticulous verification of the integrity of all three TV leaflets (preferably by 3DE en face views) is crucial before concluding that TR is secondary, since annular dilation and leaflet tethering can be also found in primary long-standing TR. (EACVI Textbook of Echocardiography)

In most severe cases, the leaflets fail to coapt, resulting in a wide-open TR. Functional TR is also a dynamic phenomenon, which shows respiratory changes of large magnitude. (EACVI Textbook of Echocardiography)

If there is a large coaptation defect or valve flail, TR should be considered severe. (EACVI Textbook of Echocardiography)

Cardioverter-defibrillator or pacemaker lead implantation: up to 39% of patients may experience the development of significant lead-induced TR (≥ grade 2). (EACVI Textbook of Echocardiography)

In these cases, 3DE may reveal leaflet perforation or impingement by the lead, most commonly affecting the septal leaflet, with consequent restricted mobility and loss of leaflets coaptation. (EACVI Textbook of Echocardiography)

In case no evident structural abnormalities of TV leaflets are seen in standard 2DE views, especially if TR is isolated with no apparent cause and/or an organic cause is suspected based on patient history (trauma, drug abuse, etc.), additional investigation should involve 3DE and/or TOE in order to rule out a primary TV involvement. (EACVI Textbook of Echocardiography)

Color Doppler with a thin small jet indicates mild tricuspid regurgitation versus a large central jet filling >50% of the RA, which indicates severe tricuspid regurgitation. (Otto, Clinical Echocardiography 6e)

First, colour flow Doppler is used for a visual estimate of the severity from multiple windows, based on the width of jet origin and its area within the RA. Detection of a large central jet or an eccentric, wall-impinging TR jet reaching the posterior wall of the RA is in favour of severe TR. (EACVI Textbook of Echocardiography)

Since jet area planimetry by colour Doppler is affected by many errors and depends on technical and haemodynamic factors, it is no longer recommended to assess TR severity. (EACVI Textbook of Echocardiography)

Vena contracta width <0.3 cm indicates mild tricuspid regurgitation versus ≥0.7 cm indicates severe tricuspid regurgitation. (Otto, Clinical Echocardiography 6e)

PISA radius <0.4 cm is seen with mild tricuspid regurgitation versus >0.9 cm with severe tricuspid regurgitation at a color Doppler Nyquist limit of 30–40 cm/s. (Otto, Clinical Echocardiography 6e)

CW Doppler shows an incomplete or faint signal with mild tricuspid regurgitation but a dense triangular signal with severe tricuspid regurgitation. (Otto, Clinical Echocardiography 6e)

The maximum velocity of the tricuspid regurgitant jet reflects the maximum pressure difference across the tricuspid valve and not the severity of regurgitation. (Otto, Clinical Echocardiography 6e)

However, the intensity of the CW signals relative to the antegrade flow signal intensity does relate to regurgitant severity. In addition, the shape of the velocity-time curve indicates the time course of the instantaneous pressure differences across the valve; an RA v-wave seen in acute regurgitation results in a more rapid decline in velocity in late systole similar to that seen in acute MR. (Otto, Clinical Echocardiography 6e)

The following are clues for a severe TR: peak E velocity greater than 1 m/s by pulsed wave (PW) Doppler in the absence of TS, TV annuloplasty or replacement, and CW Doppler velocity profile of TR with increased density and a steep falloff in velocity in late systole ('cut-off sign'). (EACVI Textbook of Echocardiography)

Hepatic vein flow in systole is normal with mild tricuspid regurgitation but reversed with severe tricuspid regurgitation. (Otto, Clinical Echocardiography 6e)

The systolic hepatic flow reversal represents a specific sign of severe TR, but its absence does not rule out a severe TR. (EACVI Textbook of Echocardiography)

Tricuspid regurgitation is best evaluated by integrating multiple parameters. (Otto, Clinical Echocardiography 6e)

The severity assessment requires the integration of multiple qualitative and quantitative parameters. (EACVI Textbook of Echocardiography)

If the TR is presumably or clearly more than mild, it should prompt a quantitative assessment based on multiple parameters of severity in order to establish its haemodynamic significance. (EACVI Textbook of Echocardiography)

Tricuspid regurgitation (TR) severity often is indeterminate due to poor image quality, technical issues with data, internal inconsistency among echo findings, or discordance with clinical findings. (Otto, Clinical Echocardiography 6e)

Good-quality echocardiographic imaging and complete data acquisition are assumed. If imaging is technically difficult, consider TEE or cardiac magnetic resonance (CMR). (Otto, Clinical Echocardiography 6e)

Vena contracta (VC) represents the cross-sectional area of the blood column as it leaves the regurgitant orifice. Thus, the VC reflects the regurgitant orifice area. (EACVI Textbook of Echocardiography)

A VC diameter larger than 7 mm is usually associated with severe TR. Intermediate values are not accurate for distinguishing moderate from mild TR. (EACVI Textbook of Echocardiography)

However, in functional TR, VC is ellipsoidal rather than circular and its longer diameter is oriented in the anteroposterior direction, therefore it does not coincide with the VC displayed in apical four-chamber view. (EACVI Textbook of Echocardiography)

PISA radius greater than 9 mm at a Nyquist limit of 28 cm/s has been associated with the presence of significant TR, while a PISA radius of 5 mm or less suggests mild TR. (EACVI Textbook of Echocardiography)

In functional TR, 2D PISA may underestimate the severity of TR by 30% and is less accurate in eccentric jets. (EACVI Textbook of Echocardiography)

The narrowest segment of the regurgitant jet, the vena contracta, occurs just distal to the regurgitant orifice, with vena contracta diameter reflecting regurgitant orifice area. (Otto, Clinical Echocardiography 6e)

Colour flow TR jet: Severe = Very large central jet or eccentric wall impinging jet. CW signal of TR jet: Severe = Dense/triangular with early peaking (peak < 2 m/s in massive TR). (EACVI Textbook of Echocardiography)

VC width (mm): Mild ≤5; Moderate 6–9; Severe >9. PISA radius (mm): Severe >9. (EACVI Textbook of Echocardiography)

EROA (mm2): Severe ≥ 40. R Vol (mL): Severe ≥ 45. (EACVI Textbook of Echocardiography)

Vena contracta width <0.3 cm indicates mild tricuspid regurgitation versus ≥0.7 cm indicates severe tricuspid regurgitation. (Otto, Clinical Echocardiography 6e)

Since jet area planimetry by colour Doppler is affected by many errors and depends on technical and haemodynamic factors, it is no longer recommended to assess TR severity. (EACVI Textbook of Echocardiography)

As many cases of pulmonary hypertension exhibit high TR velocities and only mild TR, the peak TR velocity should not be regarded as a sign of TR severity. (EACVI Textbook of Echocardiography)

However, due to its geometric assumptions, the 2D PISA method faces several limitations, especially in functional TR when the regurgitant orifice is not circular. (EACVI Textbook of Echocardiography)

The systolic hepatic flow reversal represents a specific sign of severe TR, but its absence does not rule out a severe TR. (EACVI Textbook of Echocardiography)

Severe regurgitation with a normal RV systolic pressure (as seen with tricuspid valve endocarditis) has a low maximum velocity. Mild tricuspid regurgitation in the presence of pulmonary hypertension (as seen with primary pulmonary hypertension) has a high maximum velocity. (Otto, Clinical Echocardiography 6e)

As with pulmonary vein flow reversal for severe MR, hepatic vein systolic flow reversal is specific for severe tricuspid regurgitation only when sinus rhythm is present. (Otto, Clinical Echocardiography 6e)

Hemodynamically significant tricuspid regurgitation results in progressive RV and RA enlargement due to volume overload. (Otto, Clinical Echocardiography 6e)

Conventional indices of longitudinal RV systolic function (TAPSE, S-wave) are load dependent and may not reflect the true global RV systolic function in certain conditions (severe TR, cardiac surgery, or transplantation, etc.), rendering difficult the decision to operate in the absence of symptoms. (EACVI Textbook of Echocardiography)

An end-systolic RV eccentricity index > 2 is in favour of severe TR. In acute severe TR, the RV size is often normal. In chronic severe TR, the RV is classically dilated. (EACVI Textbook of Echocardiography)

Accepted cut-off values for non-significant right-sided chambers enlargement (measurements obtained from the apical four-chamber view): Mid-RV dimension ≤ 33 mm, RV end-diastolic area ≤ 28 cm2, RV end-systolic area ≤ 16 cm2, RV fractional area change > 32%, maximal 2D RA volume ≤ 33 mL/m2. (EACVI Textbook of Echocardiography)

On 2D short-axis imaging, the ventricular septum appears 'flattened' in diastole as the increased transtricuspid stroke volume fills the RV. (Otto, Clinical Echocardiography 6e)

Severe chronic TR is commonly associated with RV, RA, and IVC dilation. In the absence of other causes (pulmonary regurgitation, left-to-right shunt, anomalous venous return, etc.), the evidence of enlarged right heart chambers supports the diagnosis of a severe TR, especially in case of conflicting Doppler findings. (EACVI Textbook of Echocardiography)

An IVC diameter < 2.1 cm is considered normal. (EACVI Textbook of Echocardiography)

IVCd of 21 mm or less that collapses by more than 50% suggests normal RA pressure = 3 mmHg (0–5 mmHg); IVCd greater than 21 mm that collapses by less than 50% suggests high RA pressure = 15 mm Hg (10–20 mmHg); otherwise, RA pressure = 8 mmHg (5–10 mm Hg). (EACVI Textbook of Echocardiography)

RA dilation is due to both pressure (v-wave) and volume (tricuspid regurgitation) overload. (Otto, Clinical Echocardiography 6e)

In the absence of a gradient across the pulmonic valve or RV outflow tract, pulmonary arterial systolic pressure (PASP) is equal to RV systolic pressure (RVSP). RVSP can be reliably determined from peak transvalvular pressure gradient (ΔP) using the simplified Bernoulli equation (ΔP = 4V2) where V is the peak velocity of TR jet, and combining this value with an estimate of the RA pressure from inferior vena cava diameter (IVCd) and respiratory changes with a sniff. (EACVI Textbook of Echocardiography)

PASP estimation is not reliable in severe free TR, when peak TR velocity is usually less than 2 m/s. The absence of a recordable TR jet should not be interpreted as a sign of normal PASP and should prompt contrast enhancement of TR signal and/or estimation of mean PAP based on pulmonary regurgitation CW Doppler signal or RV outflow PW Doppler signal. (EACVI Textbook of Echocardiography)

The maximum velocity of the tricuspid regurgitant jet reflects the maximum pressure difference across the tricuspid valve and not the severity of regurgitation. (Otto, Clinical Echocardiography 6e)

Velocities are low because little pressure difference exists between the RA and RV in systole. (Otto, Clinical Echocardiography 6e)

Secondary tricuspid regurgitation (TR) is common and allows estimation of pulmonary artery systolic pressure. (Oxford Critical Care Echo)

At present, surgery on the TV for significant functional TR should occur at the time of mitral valve surgery, as TR does not simply 'go away' after mitral valve surgery. (EACVI Textbook of Echocardiography)

Accordingly, TA dilation at the time of mitral valve surgery is now regarded as a more reliable sign of TR occurrence after surgery than TR severity itself, prompting a TV repair even if TR is mild. (EACVI Textbook of Echocardiography)

Besides TA size, coaptation height and tenting area, reflecting TV tethering, are also important predictors of the severity of early residual TR after TV repair. (EACVI Textbook of Echocardiography)

A preoperative coaptation height greater than 1 cm has been shown to predict a 55% repair failure immediately after surgery. (EACVI Textbook of Echocardiography)

At preoperative evaluation of functional TR, quantitative data regarding TA size and leaflet tethering should be included in the echocardiographic report. (EACVI Textbook of Echocardiography)

Many of these patients have significant coexisting tricuspid regurgitation, and clinical symptoms often persist postoperatively if this condition is not recognized and treated (with tricuspid annuloplasty) at the time of surgery. (Otto, Clinical Echocardiography 6e)

In massive PE the RV is hypokinetic, although there may be sparing of the apex. Secondary tricuspid regurgitation (TR) is common and allows estimation of pulmonary artery systolic pressure. (Oxford Critical Care Echo)

The peak TR velocity is usually 2.5–3.5 m/s (moderate pulmonary hypertension) as the RV can only acutely generate a pulmonary artery systolic pressure up to 60 mmHg. (Oxford Critical Care Echo)

Respiratory variation (pulsus paradoxus) in mitral and tricuspid inflows can be observed in cardiac tamponade. There is an increase in tricuspid inflow and a reciprocal decrease in mitral inflow during inspiration. (Oxford Critical Care Echo)

Functional TR is also a dynamic phenomenon, which shows respiratory changes of large magnitude. (EACVI Textbook of Echocardiography)

Severe tricuspid regurgitation may be associated with pulmonary hypertension; if this is the case, the velocity of the regurgitant jet will be increased. (Practical Perioperative TOE)

Poor acoustic windows and suboptimal patient body habitus can compromise image quality with both 2DE and three-dimensional echocardiography (3DE). In this case, transoesophageal echocardiography (TOE) is commonly performed for further diagnostic refinement. However, since the TV is located further from the transducer and obliquely oriented with respect to the Doppler beam, TOE may be more challenging than for left-sided valves. (EACVI Textbook of Echocardiography)

Several standard and modified TV views can be obtained during a TOE study at mid-oesophageal and transgastric levels. (EACVI Textbook of Echocardiography)

Unless a satisfactory short-axis view of the TV can be obtained by 2DE, the designation of individual leaflets is more reliable by 3DE. When 3D transthoracic echocardiography is unsatisfactory, 3D TOE may provide a more detailed assessment of TV morphology and function. (EACVI Textbook of Echocardiography)

Colour Doppler 3DE enables direct measurements of VC area, which correlates only modestly with VC width by 2DE, supporting the idea that TV regurgitant orifice is too complex to be described by single linear measurements. (EACVI Textbook of Echocardiography)

The hepatic veins are visualized by turning the probe to the right (anticlockwise) at the level of the transgastric mid-short-axis view until the liver is seen. (Practical Perioperative TOE)

Triage status: Sources mined — Otto Clinical Echocardiography 6e (Ch 9 and Ch 12 TR section) and EACVI Textbook of Echocardiography (Ch 37, tricuspid valve disease) provided the bulk of verbatim material; Practical Perioperative TOE (Ch 13, RV/TV/PV) and Oxford Critical Care Echo (RV, PE and tamponade chapters) supplied procedural/TOE and critical-care excerpts. Essential Echocardiography contained only fragmentary table-format TR content. All 19 substantive Q&A documents were filled with 3–7 verbatim excerpts each and are fully assignable. The one gap: the explicit expanded 5-grade scheme (severe/massive/torrential with discrete VC/EROA/RVol cut-offs) is not stated verbatim in any mounted textbook — it derives from Hahn/ASE sources (not mounted); qa-tr-5grade was therefore populated with the closest mounted verbatim cut-offs (EACVI severity table including the 'massive TR' CW note, plus Otto VC thresholds).

Ventricular pacing wires or PA catheters that cross the TV prevent normal leaflet coaptation, resulting in, at worst, mild regurgitation. (Practical Perioperative TOE)

A jet area of less than one third of the RA area is consistent with mild regurgitation. One third to two thirds is consistent with moderate regurgitation, and greater than two thirds is consistent with severe regurgitation. (Practical Perioperative TOE)

However, in the presence of marked RA dilatation, systolic flow may be antegrade despite severe regurgitation. (Practical Perioperative TOE)

The presence of pathology involving both the TV and the PV should always raise the possibility of carcinoid heart disease. (Practical Perioperative TOE)

Endocarditis is the most common cause of tricuspid regurgitation in intravenous drug users. (Practical Perioperative TOE)