E-CHALLENGE & CLINICAL DECISIONS

Feroze Mahmood, MD

Madhav Swaminathan, MD

Section Editors

Severe Tricuspid Valve Regurgitation:  

A Case for Laminar Flow

Frederick C Cobey, MD, * Maria Fritock, MD, † … Frederick W. Lombard, MD, † … Donald D.Glower, MD, § Madhav Swaminathan, MD, FAHA, FASE‡

 * Georgetown University, the Washington Hospital Center, Washington, DC

†Department of Anesthesiology, Mayo Clinic, Rochester, MN

§Department of Surgery, Division of Thoracic Surgery, Duke University Health System, Durham, NC

 ‡Department of Anesthesiology, Division of Cardiothoracic, Anesthesiology and Critical Care Medicine, Duke University Health System, Durham, NC

Address reprint requests to Madhav Swaminathan, MD, FAHA, FASE, Department of Anesthesiology, Division of Cardiothoracic, Anesthesiology and Critical Care Medicine, Box  3094/5691F HAFS Building, Duke University Health System, Durham, NC  27710.  Email:  swami001@mc.duke.edu

Key Words:  tricuspid regurgitation, Doppler, laminar flow

A 67-YEAR-OLD WOMAN presented with progressive dyspnea limiting her ability to perform daily activities. Her past medical history was significant for hyperlipidemia and Hashimoto thyroiditis. Upon further workup, a transthoracic echocardiogram (TTE) was performed, which revealed severe mitral regurgitation (MR) with mild tricuspid regurgitation (TR). Subsequently, she was scheduled for mitral valve repair. After an uneventful induction of anesthesia, an intraoperative transesophageal echocardiogram (TEE) was performed using a matrix array transducer and images acquired on an IE33 ultrasound system (Philips Healthcare, Andover, MA). The examination showed biatrial enlargement and prolapse of both the mitral and tricuspid valves. The tricuspid annulus in diastole measured 4 cm in the midesophageal 4-chamber view. The diagnosis of severe MR and mild TR was confirmed. The surgeon proceeded as planned with a mitral valve repair via a minimally invasive port-access approach. After cardiopulmonary bypass (CPB), the TEE showed a satisfactory mitral repair. However, there was hemodynamic evidence of TR with right ventricular dysfunction and an underfilled left ventricle. The central venous pressure was elevated; there were large "v" waves on the pressure waveform. Although the echocardiographic examination clearly showed TR, there was no clearly defined turbulent jet, and, therefore, the TR could not be quantified simply using the vena contracta, the proximal isovelocity surface area, or the jet area. The systolic flow across the tricuspid valve was laminar (Fig 1)and had a low peak velocity of 0.9 m/s. Both hepatic venous systolic flow reversal and a dense triangular-shaped spectral Doppler tricuspid regurgitant flow pattern also were noted. 

Fig 1 The midesophageal right ventricle inflow-outflow view showing laminar regurgitant flow into the right atrium after the discontinuation of CPB after mitral valve repair.

Challenges 

How Should the Severity of TR Be Evaluated and Graded When a Regurgitant Jet Is Laminar?

In typical cases of TR with a turbulent flow regurgitation jet, the simplest, initial, and most common approach is to use color-flow Doppler to visualize the jet. The severity of TR may be graded by mapping the area of the color jet in the right atrium.1-3 Other established approaches include measurement of the vena contracta and proximal isovelocity surface area.2,4,5 However, TR jets are often ellipsoid, often eccentrically directed, and are difficult to accurately capture in a 3-dimensional space with 2-dimensional echocardiographic planes.6 These factors likely contribute to the significant overlap seen in TR severity grades and the underestimation of TR in 20% to 30% of severe cases evaluated with color-flow Doppler.2,7 When flow is laminar, the borders of a color jet can be so difficult to appreciate that even a large jet can be missed entirely.8 Regurgitant laminar flow in contrast to flow that is turbulent allows a much greater regurgitant volume for a given transvalvular pressure gradient. The lower energy loss of laminar flow likely results in a smaller pressure drop and sustained flow. The American Society of Echocardiography (ASE) guidelines for evaluating regurgitant valve lesions suggest integrating different parameters when evaluating TR severity to avoid such errors.7 Right-sided anatomic changes consistent with severe TR include enlarged cardiac chambers with a dilated tricuspid annulus, a lack of leaflet coaptation, paradoxic septal motion, and a distended venous system.7 The morphology of the spectral tracing also may be used, with a dense triangular pattern suggestive of severe TR. A high-velocity jet does not indicate severe TR, and, indeed, laminar jets generally are associated with velocities <2 m/s.7,9,10 Antegrade and retrograde spectral patterns may almost mirror each other relating to the "to-and-fro" flow across the valve.7,10 Hepatic venous systolic flow reversal is a sensitive indicator of severe TR and also should be present.7 If most of the ASE parameters suggest moderate-to-severe TR, even in the absence of a clearly visible turbulent jet, then the presence of a significantly incompetent valve needs to be considered.

How Should Unexpected Moderate-to-Severe TR in the Operating Room Be Managed?

Recently, there has been a paradigm shift in how TR is viewed and when it should be repaired, especially in the context of left-sided valve disease. Although there is general agreement that severe TR should be repaired, guidelines are less clear regarding moderate TR.11,12 The development of late significant TR after left-sided surgery is associated with a higher rate of cardiovascular death, repeat cardiac surgery, and congestive heart failure requiring hospital admission.13 Given such findings, a large meta-analysis concluded that tricuspid dilation may be the most important risk factor for late TR and that the valve should be repaired regardless of the regurgitant severity if significant dilation is present.12 New TR that is present immediately after CPB presents a different management dilemma because this may be related to myocardial stunning or coronary air embolization and may be recoverable.

Discussion

In the case presented, the decision was made not to repair the tricuspid valve given the lack of a firm preoperative diagnosis and the absence of a conventional turbulent jet that was difficult to quantify. The patient required significant inotropic support, and on the 3rd postoperative day a TTE confirmed the presence of a laminar tricuspid jet and worsening right ventricular function (Fig 2).The patient was taken back to the operating room for possible tricuspid valve repair. The intraoperative TEE confirmed the presence of laminar TR (Fig 3)with hepatic vein systolic flow reversal (Fig 4)that resolved after the tricuspid ring annuloplasty (Fig 5).Subsequently, the patient had an uneventful postoperative recovery and was discharged in a routine fashion. A summary of echocardiographic video clips and spectral Doppler images is provided in Video 1. Upon retrospective review of the echocardiographic images, certainly repairing both valves initially could have been considered given the dilated tricuspid annulus with a prolapsing valve. The TR jet seen on both the initial TTE and prebypass TEE was also laminar and arguably misinterpreted by 2 different echocardiographers. An early case series suggested that up to a quarter of severe tricuspid jets are laminar.9 Although this number seems high, it certainly is possible that laminar TR may be an under appreciated entity. 

Fig 2 The transthoracic apical 4-chamber view showing severe TR with a laminar jet in the right atrium on the 2nd postoperative day after mitral valve repair.

Fig 3 The midesophageal 4-chamber view confirming a large laminar jet of TR before tricuspid valve repair.

Fig 4 The pulsed-wave Doppler of hepatic vein flow showing systolic flow reversal (arrow).

Fig 5 The midesophageal 4-chamber view showing a satisfactory repair of the tricuspid valve without evidence of TR on color-flow Doppler.

Conclusions

The case presented highlights the difficulty in quantifying a TR jet that shows laminar flow. When this occurs immediately after CPB intraoperatively in the setting of mitral valve surgery, the issues become even more complex. Surgical decision making is also complicated after decannulation, especially in the minimally invasive approach. Given the growing body of evidence that early intervention may be indicated in cases of TR, especially in the setting of left-sided valve surgery and the possibility of laminar flow, vigilance for identifying such cases of "silent" regurgitation is warranted.9,12 

References

1. Y. Shapira, A. Porter, M. Wurzel, et al. Evaluation of tricuspid regurgitation severity: Echocardiographic and clinical correlation J Am Soc Echocardiogr 11:652-659, 1998

2. G. Grossmann, M. Stein, M. Kochs, et al. Comparison of the proximal flow convergence method and the jet area method for the assessment of the severity of tricuspid regurgitation Eur Heart J 19:652-659, 1998

3. F. Gonzalez-Vilchez, J. Zarauza, J.A. Vazquez de Prada, et al. Assessment of tricuspid regurgitation by Doppler color flow imaging: Angiographic correlation Int J Cardiol 44:275-283, 1994

4. S. Yamachika, C.L. Reid, D. Savani, et al. Usefulness of color Doppler proximal isovelocity surface area method in quantitating valvular regurgitation J Am Soc Echocardiogr 10:159-168, 1997

5. W.I. Yang, C.Y. Shim, M.K. Kang, et al. Vena contracta width as a predictor of adverse outcomes in patients with severe isolated tricuspid regurgitation J Am Soc Echocardiogr 24:1013-1019, 2011

6. J.M. Song, M.K. Jang, Y.S. Choi, et al. The vena contracta in functional tricuspid regurgitation: A real-time three-dimensional color Doppler echocardiography study J Am Soc Echocardiogr 24:663-670, 2011

7. W.A. Zoghbi, M. Enriquez-Sarano, E. Foster, et al. Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography J Am Soc Echocardiogr 16:777-802, 2003

8. S. Akamatsu, N. Ueda, E. Terazawa, et al. Mitral prosthetic dehiscence with laminar regurgitant flow signals assessed by transesophageal echocardiography Chest 104: 1911-1913, 1993

9. K. Yoshida, J. Yoshikawa, T. Akasaka, et al. Silent severe tricuspid regurgitation: A study by Doppler echocardiography J Cardiol 19:187-194, 1989

10. S. Minagoe, S.H. Rahimtoola, P.A. Chandraratna. Significance of laminar systolic regurgitant flow in patients with tricuspid regurgitation: A combined pulsed-wave, continuous-wave Doppler and two-dimensional echocardiographic study Am Heart J 119:627-635, 1990

11. R.O. Bonow, B.A. Carabello, K. Chatterjee, et al. Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 guidelines for the management of patients with valvular heart disease): Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons Circulation 2008:e523-e661, 2008

12. G. Bianchi, M. Solinas, S. Bevilacqua, et al. Which patient undergoing mitral valve surgery should also have the tricuspid repair? Interact Cardiovasc Thorac Surg 9:1009-1020, 2009

13. H. Song, M.J. Kim, C.H. Chung, et al. Factors associated with development of late significant tricuspid regurgitation after successful left-sided valve surgery Heart 95:931-936, 2009

Fig 1 The midesophageal right ventricle inflow-outflow view showing laminar regurgitant flow into the right atrium after the discontinuation of CPB after mitral valve repair. 

Fig 2 The transthoracic apical 4-chamber view showing severe TR with a laminar jet in the right atrium on the 2nd postoperative day after mitral valve repair.

Fig 3 The midesophageal 4-chamber view confirming a large laminar jet of TR before tricuspid valve repair.

Fig 4 The pulsed-wave Doppler of hepatic vein flow showing systolic flow reversal (arrow).

Fig 5 The midesophageal 4-chamber view showing a satisfactory repair of the tricuspid valve without evidence of TR on color-flow Doppler.