Hellenic Journal of Cardiology (2016) 57, 145e151

Available online at www.sciencedirect.com

ScienceDirect

journal homepage: http: / /www.journals .elsevier .com/hel lenic- journal-of-cardiology/

REVIEW ARTICLE

Echocardiographic Evaluation of TricuspidProsthetic Valves: An Update

Dimitrios Maragiannis, MD, FASE, FACC a,*,Constantina Aggeli, MD b, Sherif F. Nagueh, MD, FASE c

a Cardiovascular Imaging Section, 401 General Army Hospital of Athens, Athens, Greeceb 1st Department of Cardiology, National and Kapodistrian University of Athens, Hippokration GeneralHospital, Athens, Greecec Houston Methodist DeBakey Heart and Vascular Center, Houston, TX, USA

Received 21 November 2014; accepted 8 June 2015Available online 12 July 2016

KEYWORDSTricuspid valve;Prosthetic valvedysfunction;Three-DimensionalEchocardiography

* Corresponding author. Dimitrios MCardiovascular Imaging Section, 401Athens, Athens, Greece. Tel.: þ30693

E-mail address: dmarajohn@gmail.Peer review under responsibility

Society.

http://dx.doi.org/10.1016/j.hjc.20151109-9666/ª 2016 Hellenic Cardiologilicense (http://creativecommons.org/

Abstract This review focuses on the diagnostic value of novel echocardiographic techniquesand the clinical application of recently described algorithms to assess tricuspid prostheticvalve function.ª 2016 Hellenic Cardiological Society. Publishing services by Elsevier B.V. This is an open ac-cess article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Accurate prosthetic valve assessment is of great impor-tance for clinical decisions. Current guidelines recommendnoninvasive evaluation in patients with tricuspid prostheticvalves (TPV) with Doppler echocardiography.1 NormalDoppler derived indices such as transprosthetic peak ve-locity, mean transprosthetic pressure gradient and pressurehalf time (PHT) have been reported, although not vali-dated. Studies using large series of early postoperative data

aragiannis, MD, FASE, FACC,General Army Hospital of

7303553.com (D. Maragiannis).of Hellenic Cardiological

.06.002cal Society. Publishing services bylicenses/by-nc-nd/4.0/).

have proposed additional parameters and clinically helpfulalgorithms to evaluate both bioprosthetic and mechanicalvalves in the tricuspid position.2,3 The addition of newertechniques such as three-dimensional echocardiographymay also add value to traditional tricuspid prosthetic valveevaluation. The purpose of this review is to focus on thesenew proposed indices to better describe the nature ofpathologic TPV dysfunction.

2. Echocardiographic Evaluation of TricuspidProsthetic Valve Function

2.1. 2D Echocardiography

Comprehensive evaluation either with transthoracic echo-cardiography (TTE) or transesophageal echocardiography

Elsevier B.V. This is an open access article under the CC BY-NC-ND

146 D. Maragiannis et al.

(TEE) has been traditionally used to assess TPV function andstructure. Standard transthoracic (RV inflow, four chamber,RV inflow-outflow and subcostal views) and transesophagealviews (mid-esophageal (ME) 4 chamber, the ME inflow-outflow, the ME-modified bicaval TV and the transgastric(TG) RV inflow-outflow view)4 can visualize the appropriateseating of the TPV in the annulus, diagnose TPV degener-ation due to leaflet calcification and thickening andpossibly identify causes of obstruction (thrombus, pannus,vegetation) or regurgitation (vegetation, dehiscence).Transthoracic imaging can provide excellent quality imagesbecause the tricuspid valve is an anterior structure. 2Dechocardiography may also provide additional informationabout RV and RA size and function, which results in an in-tegrated approach to evaluate the presence and severity ofTPV dysfunction.

2.2. Color Doppler Imaging

Color Doppler shows the blood flow pattern across theprostheses. In bioprosthetic TPVs the diastolic flow jet issmooth and wide, with no apparent aliasing. In mechanicalTPVs, the antegrade color Doppler jet direction and patternmay differ among variable valve types (ball cage, bileafletvalves). Color Doppler is also the preferred method forassessing TPV transprosthetic and periprosthetic regurgi-tation. Mild regurgitant washing jets are apparent in nor-mally functioning mechanical TPVs, while mild regurgitanttransprosthetic jets might be rarely seen in normallyfunctioning bioprosthetic TPVs early post-surgery. Acousticshadowing from the valve’s metallic elements may inter-fere with color Doppler interrogation, and views withminimal shadowing are preferred with TTE (the RV inflowand the subcostal views). Multiplane TEE may offer addi-tional views, avoiding acoustic shadowing, especially incases when significant transprosthetic or periprostheticregurgitation is suspected.

2.3. Spectral Doppler Echocardiography

Doppler echocardiography is currently recommended forTPV evaluation early post implantation.1 The trans-prosthetic velocity can be noninvasively estimated withcontinuous wave (CW) Doppler and pressure gradient (peakand mean) can be estimated by applying the simplifiedBernoulli equation. Adequate Doppler alignment with flowappears to be superior with traditional TTE views, whereasvalve interrogation with CW by the TEE approach might bechallenging in some cases. Current guidelines1 reportnormal transprosthetic gradient and pressure half timevalues; however, additional Doppler derived parameterssuch as the effective orifice area (EOA) and time velocityintegral (TVI) ratio have been recently described in largerpopulation studies2,3 to provide a comprehensive evalua-tion of TPV function.

Respiratory transprosthetic velocities may vary duringthe respiratory cycle; therefore, Doppler measurementsfrom at least five cycles have been proposed to be averagedin current guidelines whether the patient is in sinus rhythmor atrial fibrillation. In cases of significant Doppler velocityvariation, more cycles might be averaged.1

2.4. Mean Gradient

Current guidelines state that normally functioning tricuspidprostheses have a mean gradient <6mmHg.1 Recently,Blawet et al. have shown that a transvalvular meangradient <9mmHg identifies normally functioning bio-prosthetic tricuspid valves.2 They included a variety ofdifferent types of valves and sizes (Carpentier-EdwardsDuraflex, Medtronic Mosaic, St. Jude Medical Biocor,Carpentier-Edwards Perimount and Medtronic Hancock II).In another study evaluating mechanical tricuspid bileafletvalves, a mean gradient <6 mmHg reflected normallyfunctioning valves.3 However, it should be noted that themean gradient may be altered significantly in high flowstates (anemia, hyperthyroidism, sepsis), where the valvesare still functioning normally despite higher reported gra-dients.1 Other conditions such as constrictive pericarditis orelevated right ventricular diastolic pressures can alsoaffect transprosthetic gradients. Although high right atrialpressure or a noncompliant right atrium can affect thecontour of the continuous wave Doppler in cases oftricuspid regurgitation reflecting the relation of pressuresacross the prosthesis, their contribution to the trans-valvular diastolic mean gradient assessment remainsunclear.

2.5. Pressure Half-Time

Pressure half time (PHT) is the time it takes for thetransprosthetic peak gradient measured by Doppler todecline to half of its initial value. Current guidelinesrecommend that a PHT<230 msec indicates the absence ofsignificant valve stenosis.1 It should be noted, that roundedspectral Doppler contours are not uncommon and PHTcannot be reliably evaluated in these cases. The normalvalue of 200-238 msec has been proposed as an upper limitfor bioprosthetic TVPs.5,6 Blawet et al recently showed thatnormally operating bioprostheses in the tricuspid positionhave a PHT <200 msec.2 Different values have been pub-lished for the normal mechanical tricuspid prostheses. In arecent study, a PHT<130 msec was associated with normalfunction in bileaflet mechanical tricuspid prostheses (St.Jude Medical Standard, CarboMedics Standard).3 This isconsistent with previously published reports, where themean PHT ranged between 102-120 msec for St Judebileaflet mechanical valves (St. Jude Medical Standard).7,8

In a past study in which older prostheses types were used,Conolly et al. demonstrated that mean PHT for normal ballcaged valves was 144� 46 msec.5

2.6. TVI Ratio for Tricuspid Prosthetic Valves

Similar to mitral mechanical prosthetic valves, a ratio of(TVITPV) to the left ventricle outflow tract TVI (TVILVOT) hasbeen investigated as a useful index of tricuspid prostheticvalve function. Blauwet et al. demonstrated that a peaktricuspid E velocity <2.1 m/sec, TVITPV/TVILVOT<3.3 andPHT<200msec were predictive of normal TPV function intricuspid valve bioprostheses.2 The same group has alsoproposed the use of the TVI ratio for the evaluation ofmechanical tricuspid valve prostheses. A peak tricuspid E

Tricuspid Prosthetic Valve Evaluation 147

velocity <1.9 m/sec, TVITPV/TVILVOT<2.0 and PHT<130msec was found to be predictive of normal mechanical TPVfunction.3

2.7. Effective Orifice Area (EOA)

Effective orifice area (EOA) represents the area throughwhich streamline or frictionless flow occurs, and it has beentraditionally evaluated by echocardiography either usingthe pressure half time or the continuity equation method.However, the use of either the continuity equation or thepressure half time method to calculate EOA for TPVs hasnot been validated with in vitro data. In a small studyincluding only five TPVs, Fawsy et al., using both echocar-diography and catheterization data, demonstrated thatEOAZ 190/PHT by echocardiography compares well withthe invasively derived EOA.9 Recent comprehensive Dopplerechocardiography retrospective studies have shown thatEOA calculated by the pressure half time method was largerthan the one calculated with the continuity equation.2,3

Those studies have also proposed normal reference valuesfor bioprosthetic and mechanical valve EOA in the tricuspidposition.

Figure 1 The figure shows a two-dimensional (2D) and continuous(red arrow) in a 66-year-old female and the same valve one month laa normal mechanical tricuspid valve in the apical four-chamber vmeasured at a heart rate of 86 bpm. Panel B: 2D and CW in an obstruone month later due to valve thrombosis. Severely elevated transprate of 97 bpm.

3. Tricuspid Prosthetic Valve Obstruction

Both tricuspid bioprostheses and tricuspid mechanicalvalves may fail early or late after implantation. Commonmechanisms of valve obstruction include leaflet degenera-tion, pannus formation, thrombus or vegetation obstructingtransvalvular flow (Figure 1). Bioprosthetic TPV obstructionis not uncommon and occurs due to leaflet thickening andcalcification. It has been reported that leaflet degenerationvaries between 0.4 and 2.2% patient-years in previouslypublished studies.10,11 Mechanical TPVs are commonlyobstructed by thrombus or pannus formation, and throm-bosis has been reported at 0.5%-3.3% patient-years inearlier studies.11e13 Doppler measurements have beenshown to accurately predict TPV stenosis when comparedwith invasive hemodynamic data.14,15 Current guidelinesrecommend 2D echocardiography and Doppler derived pa-rameters to assess TPV dysfunction due to valve stenosis.1

3.1. 2D Echocardiography

Both TTE and TEE may verify abnormal leaflet structure dueto degeneration with calcification and abnormal motion,

-wave (CW) examination of a normal mechanical tricuspid valveter after acute thrombosis. Panel A: 2D and CW examination ofiew. Normal transprosthetic mean gradient of 2.8 mmHg wascted mechanical tricuspid valve (red arrow) of the same femalerosthetic mean gradient of 15 mmHg was measured at a heart

Figure 2 The figure shows the transesophageal echocardio-gram (TEE) images from a 40-year-old woman with moderateprosthetic valve regurgitation. Severely thickened and calci-fied leaflets and moderate tricuspid regurgitation in a degen-erated tricuspid bioprosthesis (red arrow).

148 D. Maragiannis et al.

with visualization of vegetations or thrombi when present.TEE may also measure thrombus size and impact the deci-sion on whether to use thrombolytic therapy.16

3.2. Color Flow Imaging

Color Doppler may add supportive information to TPVevaluation. Obstructive flow is usually turbulent and ap-pears as a high velocity narrow color jet with aliasing. Aflow convergence zone may be noted proximal to the rightatrium, although acoustic shadowing may conceal thisfinding.

3.3. Spectral Doppler

In a large series of patients with different types of tricuspidbioprostheses during the early postoperative period, Bla-wet et al. have demonstrated that a PHT �200 msec ispredictive of valve stenosis.2 These findings are in line withcurrent guidelines (PHT>230 msec).1 In another study, thesame group has reported that a PHT�130 msec identifiesobstructed bileaflet tricuspid mechanical valves.3 Additiveparameters to the diagnosis of TPV obstruction are elevatedmean gradient �9 mmHg, which is highly suggestive oftricuspid bioprosthetic valve stenosis, and �6 mmHg inmechanical TPVs, an elevated velocity �2.1 m/sec intricuspid bioprostheses, whereas an abnormal value formechanical bileaflet prostheses has been reported to be�1.9 m/sec. An abnormal EOA is also supportive of TPVobstruction.2,3

4. Tricuspid Valve Patient Prosthesis Mismatch

Patient prosthesis mismatch (PPM) occurs when the pros-thesis is small for a patients’ body size. Clinically, it pre-sents with an elevated transprosthetic valve gradient and asmall valve EOA. Blawet et al. defined PPM as an indexedEOA (iEOA) <1.2 cm2/m2. Severe PPM was defined as iEOA�0.9 cm2/m2.2,3 A PHT�200 msec for bioprosthetic and�130 msec for mechanical tricuspid valve prostheses candifferentiate the obstructed TPV from one with PPM.

5. Tricuspid Prosthetic Valve Regurgitation

TTE is the primary technique to diagnose pathologictricuspid prosthetic valve regurgitation. TEE may offeradditional information, showing the cause and the locationof regurgitation when TTE is not diagnostic. Currentguidelines recommend an integrated approach to quantifyregurgitation using 2D, color Doppler and spectral Dopplerparameters.1 Pathologic regurgitation can occur in bothbioprosthetic and mechanical tricuspid prostheses(Figure 2). However, no echocardiographic parametersassociated with significant pathologic prosthetic tricuspidparavalvular or transprosthetic regurgitation have beenreported in clinical studies. In bioprosthetic valves, trans-prosthetic regurgitation is usually caused by valve degen-eration with thickening and calcification of valve leaflets orleaflet perforation due to endocarditis. In mechanicalprostheses, pathologic regurgitation may occur when

pannus, thrombus or vegetation prevent complete leafletclosure. Paravalvular tricuspid regurgitation, although rare,occurs when blood leaks backward during systole outsidethe prosthetic ring. Paravalvular regurgitation reflectsusually suture loosening or infective endocarditis with thepresence or absence of abscess formation.

A limited amount of regurgitation is normal in mechanicaltricuspid prostheses. Regurgitant jets have a low velocityprofile, they appear smooth and homogenous with colorDoppler, and they are of short duration. Their flow patternvaries within different valve types. Regurgitation is notusually present in bioprosthetic valves; however, in the earlypostoperative period, some trace of backflow may be seen.

5.1. 2D Echocardiography

2D echocardiography using standard views with either TTEor TEE may provide a clear delineation of prosthetic valvepathology and etiology of regurgitation (dehiscence,degeneration, endocarditis, mechanical leaflet fixed in anopen position). Identifying the cause of regurgitation isextremely important because clinical decisions will bebased upon the echocardiographic diagnosis. The presenceof substantial enlargement in the right chamber is sup-portive of significant prosthetic valve regurgitationalthough other causes may commonly affect the size of theright chamber. Inferior vena cava dilatation is also associ-ated with significant TPV regurgitation.

5.2. Color Flow Imaging

Although color Doppler has proven to be a useful methodfor quantifying regurgitant lesion severity in nativetricuspid valves, its value in pathologic TPV regurgitationmay be more limited due to acoustic attenuation and re-verberations by the prosthesis. Importantly, TTE can iden-tify transprosthetic or paravalvular regurgitation, assessqualitatively and quantitatively the severity of

Tricuspid Prosthetic Valve Evaluation 149

regurgitation by using the radius of flow convergence andvena contracta measurements. Similar to native valves, avena contracta width >0.7 cm is highly specific and sensi-tive for severe TR.1 An alternative strategy involving TEEmay add more precise information about regurgitant jetlocation and its direction and size, especially when TTE isnot conclusive.

5.3. Spectral Doppler

Spectral Doppler derived parameters should be consideredin addition to 2D and color flow imaging. An elevatedtricuspid peak E velocity (�1.9 m/sec in bioprosthetic or�2.1 m/sec in mechanical TPVs) and a holosystolic flowreversal in hepatic venous flow by Pulse Wave (PW) Dopplerare associated with significant regurgitation. However,existing data suggest that both parameters may not be al-ways specific for severe TR. Another common feature ofseverity by continuous wave (CW) Doppler is a dense, earlypeaking jet. Recently, Blawet et al. have reported thatspectral Doppler parameters increase the confidence ofidentifying severe regurgitant lesions. With severe bio-prosthetic TR, peak tricuspid E velocity is usually �2.1 m/

Figure 3 Three-dimensional transesophageal echocardiography (Tthe tricuspid position. Panel A, B: Two-dimensional orthogonal londata. Panel C: Short axis (en face) view of the valve surgical ring. Pabioprosthetic valve.

sec, with TVITPV/TVILVOT ratio �3.3 and PHT<200 msec.2

For severe mechanical TR, peak tricuspid E velocity is�1.9 m/sec, TVITPV/TVILVOT ratio �2.0 and PHT<130 msec.3

In summary, dehiscence of the prosthesis by 2D echo-cardiography, a wide vena contracta width (�0.7 cm) and/or the presence of significant flow convergence zone whencombined with dilated right heart chambers are all sup-portive of severe tricuspid prosthetic valvular or para-valvular regurgitation. Spectral Doppler parameterspreviously described may enhance the confidence of thediagnosis.

6. 3D Echocardiography

Multiplane TEE is indicated for the evaluation of prostheticvalve regurgitation (severity and mechanism), the evalua-tion of suspected valve obstruction (presence of thrombusor pannus), the evaluation of endocarditis and associatedabnormalities (vegetation, valve abscess, fistula, pseudoa-neurysm) and for guidance of transcatheter procedures.4

3D TTE and TEE offer additional diagnostic value in iden-tifying pathologic TPVs (Figure 3). A very limited number ofstudies have addressed the role of novel technology in

EE) of a normally functioning 10-year-old bioprosthetic valve ing planes of the bioprosthetic valve, created by the volumetricnel D: 3D volume data, showing the thin leaflets of the tricuspid

150 D. Maragiannis et al.

prosthetic valve evaluation in the last decade, but thenumber of the TPVs evaluated in these studies was verysmall.17,18 According to recently published guidelines, thenative tricuspid valve’s evaluation is enhanced by 3Dechocardiography at the mid-esophageal 4 chamber-viewfrom 0o to 30o or at the 40o transgastric view using anarrow-angle or a wide-angle acquisition with either asingle-beat or multiple-beat acquisition.4,19 Dehiscencelocations, regurgitant jet sites, vegetations, degenerativeleaflets, thrombi and immobile leaflets can be identified by3D TEE.20,21 The limited temporal and spatial resolution areinherent limitations of 3D echocardiography. Stitching ar-tifacts are also prominent in patients with arrhythmias.Further research is needed to investigate the diagnosticrole of 3D echocardiography in evaluating TPV structureand function.

7. Tricuspid Transcatheter Valve-in-valveImplantation

2D and 3D TEE have been successfully used for thedeployment of percutaneous transcatheter valves inseverely dysfunctional bioprosthetic TPVs in high surgicalrisk patients using the transatrial, transjugular or trans-femoral approach. TEE is the modality of choice duringtranscatheter valve in valve implantation.4 Only a fewcases in literature22e29 have been reported, mostlydescribing implantation of either the Melody valve (Med-tronic, Inc., Minneapolis, MN, USA) or Edwards SAPIENtranscatheter valve (Edwards Lifesciences, Irvine, CA,USA). Currently, Doppler parameters and normal referencevalues from surgical prosthetic valves are used in clinicalpractice to assess percutaneous valve function; however,additional data on the hemodynamic performance of thesevalves using Doppler derived parameters in larger patientpopulations are needed.

8. The role of other modalities

An ECG gated multidetector computed tomography col-lecting 3D dataset may reconstruct and visualize the valveanatomy, paravalvular regurgitation on any plane, identifyabscesses, thrombus or pannus in most cases on an offlineanalysis system. MDCT is an accurate modality for identi-fying the mechanism of valve obstruction; however, radia-tion, contrast use and artifacts from the prostheses are stilla concern.

CMR may provide anatomic (anatomic orifice area byplanimetry) and functional information (peak velocitythrough the valve, calculation of regurgitant volume/frac-tion). By using volumetric data from the right ventricleejection fraction calculation and the phase contrast mea-surement of flow through the pulmonary artery, CMR mayevaluate tricuspid regurgitant volume/fraction. However,both bioprosthetic and (especially) mechanical valvesgenerate significant metallic artifacts, which creates diffi-culties in interpretation. Phase contrast measurement ofthrough plane velocity can be underestimated if it is notperpendicular to the flow direction and should be measuredat the location of maximal velocity. The temporal

resolution of CMR is lower than continuous wave Doppler,and annular motion during cardiac cycle generates addi-tional sources of error for velocity measurements. To ourknowledge, there are no published reports describing theaccuracy of CMR measurements for tricuspid valveprostheses.

9. Conclusion

Echocardiography is the primary diagnostic modality forthe evaluation of tricuspid prosthetic valve function. Earlypostoperative examination and comparative echocardio-graphic follow-up studies may unmask possible valvedysfunction. In the era of multimodality imaging, echo-cardiography remains a widely available inexpensivemethod with enough evidence incorporated in currentguidelines to accurately evaluate tricuspid prostheticvalve function. The diagnostic role of 3D echocardiogra-phy to the routine assessment of tricuspid prostheticvalves warrants further investigation in larger populationstudies.

References

1. Zoghbi WA, Chambers JB, Dumesnil JG, et al. Recommenda-tions for evaluation of prosthetic valves with echocardiographyand Doppler ultrasound: a report From the American Society ofEchocardiography’s Guidelines and Standards Committee andthe Task Force on Prosthetic Valves, developed in conjunctionwith the American College of Cardiology Cardiovascular Imag-ing Committee, Cardiac Imaging Committee of the AmericanHeart Association, the European Association of Echocardiog-raphy, a registered branch of the European Society of Cardi-ology, the Japanese Society of Echocardiography and theCanadian Society of Echocardiography, endorsed by theAmerican College of Cardiology Foundation, American HeartAssociation, European Association of Echocardiography, aregistered branch of the European Society of Cardiology, theJapanese Society of Echocardiography, and Canadian Societyof Echocardiography. J Am Soc Echocardiogr. 2009;22:975e1014.

2. Blauwet LA, Danielson GK, Burkhart HM, et al. Comprehensiveechocardiographic assessment of the hemodynamic parame-ters of 285 tricuspid valve bioprostheses early after implanta-tion. J Am Soc Echocardiogr. 2010;23:1045e1059.

3. Blauwet LA, Burkhart HM, Dearani JA, et al. Comprehensiveechocardiographic assessment of mechanical tricuspid valveprostheses based on early post-implantation echocardiographicstudies. J Am Soc Echocardiogr. 2011;24:414e424.

4. Hahn RT, Abraham T, Adams MS, et al. Guidelines for per-forming a comprehensive transesophageal echocardiographicexamination: recommendations from the American Society ofEchocardiography and the Society of Cardiovascular Anesthe-siologists. J Am Soc Echocardiogr. 2013;26:921e964.

5. Connolly HM, Miller Jr FA, Taylor CL, Naessens JM, Seward JB,Tajik AJ. Doppler hemodynamic profiles of 82 clinically andechocardiographically normal tricuspid valve prostheses. Cir-culation. 1993;88:2722e2727.

6. Aoyagi S, Tomoeda H, Kawano H, Yokose S, Fukunaga S.Doppler echocardiographic evaluation of prosthetic valves intricuspid position. Asian Cardiovasc Thorac Ann. 2003;11:193e197.

7. Aoyagi S, Nishi Y, Kawara T, Oryoji A, Kosuga K, Ohishi K.Doppler echocardiographic evaluation of St. Jude Medical

Tricuspid Prosthetic Valve Evaluation 151

valves in the tricuspid position. J Heart Valve Dis. 1993;2:279e286.

8. Sezai A, Shiono M, Akiyama K, et al. Doppler echocardiographicevaluation of St. Jude Medical valves in the tricuspid position:criteria for normal and abnormal valve function. J CardiovascSurg. 2001;42:303e309.

9. Fawzy ME, Mercer EN, Dunn B, al-Amri M, Andaya W. Dopplerechocardiography in the evaluation of tricuspid stenosis. EurHeart J. 1989 Nov;10(11):985e990.

10. Ratnatunga CP, Edwards MB, Dore CJ, Taylor KM. Tricuspidvalve replacement: UK Heart Valve Registry mid-term resultscomparing mechanical and biological prostheses. Ann ThoracSurg. 1998;66:1940e1947.

11. Garatti A, Nano G, Bruschi G, et al. Twenty-five year outcomesof tricuspid valve replacement comparing mechanical andbiologic prostheses. Ann Thorac Surg. 2012;93:1146e1153.

12. Nakano K, Koyanagi H, Hashimoto A, Ohtsuka G, Nojiri C.Tricuspid valve replacement with the bileaflet St. Jude Medicalvalve prosthesis. J Thorac Cardiovasc Surg. 1994;108:888e892.

13. Peterffy A, Szentkiralyi I. Mechanical valves in tricuspid posi-tion: cause of thrombosis and prevention. Eur J CardiothoracSurg. 2001;19:735e736.

14. Wilkins GT, Gillam LD, Kritzer GL, Levine RA, Palacios IF,Weyman AE. Validation of continuous-wave Doppler echocar-diographic measurements of mitral and tricuspid prostheticvalve gradients: a simultaneous Doppler-catheter study. Cir-culation. 1986;74:786e795.

15. Burstow DJ, Nishimura RA, Bailey KR, et al. Continuous waveDoppler echocardiographic measurement of prosthetic valvegradients. A simultaneous Doppler-catheter correlative study.Circulation. 1989;80:504e514.

16. Tong AT, Roudaut R, Ozkan M, et al, Prosthetic ValveThrombolysis-Role of Transesophageal Echocardiography (PRO-TEE) Registry Investigators. Transesophageal echocardiographyimproves risk assessment of thrombolysis of prosthetic valvethrombosis: results of the international PRO-TEE registry. J AmColl Cardiol. 2004;43:77e84.

17. Sugeng L, Shernan SK, Weinert L, et al. Real-time three-dimensional transesophageal echocardiography in valve dis-ease: comparison with surgical findings and evaluation ofprosthetic valves. J Am Soc Echocardiogr. 2008;21:1347e1354.

18. Krim SR, Vivo RP, Patel A, et al. Direct assessment of normalmechanical mitral valve orifice area by real-time 3D echocar-diography. JACC Cardiovasc Imaging. 2012;5:478e483.

19. Lang RM, Badano LP, Tsang W, et al. EAE/ASE recommendationsfor image acquisition and display using three-dimensionalechocardiography. Eur Heart J Cardiovasc Imaging. 2012;13:1e46.

20. Naqvi TZ, Rafie R, Ghalichi M. Real-time 3D TEE for the diag-nosis of right-sided endocarditis in patients with prostheticdevices. JACC Cardiovasc Imaging. 2010;3:325e327.

21. Cheng HL, Cheng YJ, Wang YC, Fan SZ. A stenotic bioprostheticvalve in the tricuspid position: real-time 3-dimensional trans-esophageal echocardiography as a useful supplement to con-ventional assessment. Anesth Analg. 2012;115:253e256.

22. Hon JK, Cheung A, Ye J, et al. Transatrial transcathetertricuspid valve-in-valve implantation of balloon expandablebioprosthesis. Ann Thorac Surg. 2010;90:1696e1697.

23. Gurvitch R, Cheung A, Ye J, et al. Transcatheter valve-in-valveimplantation for failed surgical bioprosthetic valves. J Am CollCardiol. 2011;58:2196e2209.

24. Hoendermis ES, Douglas YL, van den Heuvel AF. PercutaneousEdwards SAPIEN valve implantation in the tricuspid position:case report and review of literature. EuroIntervention. 2012;8:628e633.

25. Gaia DF, Palma JH, de Souza JA, Buffolo E. Tricuspid trans-catheter valve-in-valve: an alternative for high-risk patients.Eur J Cardiothorac Surg. 2012;41:696e698.

26. Petit CJ, Justino H, Ing FF. Melody valve implantation in thepulmonary and tricuspid position. Catheter Cardiovasc Interv.2013 Dec 1;82(7):E944eE946.

27. Gerosa G, D’Onofrio A, Tessari C, Pittarello D, Rubino M,Colli A. Open transcatheter tricuspid balloon expandablevalve-in-valve implantation for failed bioprosthesis. J ThoracCardiovasc Surg. 2013;146:e3ee5.

28. Ribichini F, Pesarini G, Feola M, et al. Transcatheter tricuspidvalve implantation by femoral approach in trivalvular heartdisease. Am J Cardiol. 2013;112:1051e1053.

29. Daneault B, Williams MR, Leon MB, Paradis JM, Kodali SK.Transcatheter tricuspid valve-in-valve replacement resulting in4 different prosthetic heart valves in a single patient. J Am CollCardiol. 2013; Jan 15;61:e3.