HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Jose L. Navia Nicolas A. Brozzi Chanapong Kittayarak Edward R. Nowicki Eugene H. Blackstone Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Navia, J. L. Articles by Blackstone, E. H. Search for Related Content PubMed PubMed Citation Articles by Navia, J. L. Articles by Blackstone, E. H. Related Collections Valve disease

---

Original Articles: Adult Cardiac

Moderate Tricuspid Regurgitation With Left-Sided Degenerative Heart Valve Disease: To Repair or Not to Repair?

Departments of Thoracic and Cardiovascular Surgery and Cardiovascular Medicine, Heart and Vascular Institute, and Department of Quantitative Health Sciences, Research Institute, Cleveland Clinic, Cleveland, Ohio

Accepted for publication August 11, 2011.

^_* Address correspondence to Dr Navia, Department of Thoracic and Cardiovascular Surgery, Heart and Vascular Institute, Cleveland Clinic, 9500 Euclid Ave, Desk J4-1, Cleveland, OH 44195 (Email: naviaj{at}ccf.org).

Presented at the Forty-seventh Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31–Feb 2, 2011.

	Abstract

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
Background: Uncertainty about long-term effects of surgically unaddressed moderate (2+) secondary tricuspid valve (TV) regurgitation (TR) accompanying left-sided degenerative heart valve disease led us to identify reasons for and factors associated with TV repair, compare safety and clinical effectiveness of relieving TR, and identify factors associated with severe (3/4+) postoperative TR.

Methods: From 1997 to 2008, 1,724 patients with 2+ TR underwent 830 mitral, 703 aortic, and 191 double-valve procedures; 91 (5%) had concomitant TV repair. Logistic regression analysis was used to identify factors associated with TV repair and for propensity-matched comparison of safety (in-hospital morbidity, mortality) and effectiveness of TV repair (longitudinal echocardiographic assessment of postoperative TR and New York Heart Association class, TV intervention, survival).

Results: Factors associated with TV repair of 2+ TR included larger right ventricles and left ventricles (p < 0.001), greater TV tethering height (p = 0.0002), and prior concurrent mitral valve procedures (p 0.004). In-hospital complications, subsequent TV interventions, and intermediate-term survival were similar for matched patients. The TV repair patients had less 3/4+ TR at discharge (7% versus 15%), sustained out to 3 years. No TV repair (p = 0.05), female sex (p < 0.0001), and mitral valve replacement (p = 0.008) were associated with 3/4+ TR.

Conclusions: A TV repair for moderate TR concomitant with surgery for degenerative left-sided heart valve disease is reasonable to provide an opportunity to prevent its progression and development of right ventricle dysfunction, particularly for patients with important right ventricle remodeling and evidence of right ventricular failure, and for patients with advanced left-sided disease requiring mitral valve replacement.

	Introduction

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
At one time, moderate or less tricuspid valve (TV) regurgitation (TR) secondary to degenerative left-sided heart valve disease was expected to diminish or disappear after surgical correction of left-sided valve pathology [1]. This led to a conservative approach to secondary TR. As far back as the 1970s, however, some recommended addressing secondary TR, and some do today if the TV anulus is dilated [2-5]. Yet, the small number of TV procedures performed compared with left-sided ones suggests that the conservative approach still prevails. Therefore, we sought to identify reasons for and factors associated with TV repair for 2+ TR concomitant with surgery for degenerative left-sided heart valve disease, to compare safety and clinical effectiveness of relieving TR, and to identify factors associated with severe postoperative TR.

	Patients and Methods

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
Patients
From January 1997 to January 2008, 11,788 patients underwent surgery for left-sided degenerative heart valve disease at Cleveland Clinic. Among these, 5,629 (48%) had no TR (0+), 3,544 (30%) had mild TR (1+), 1,724 (15%) had moderate TR (2+), 636 (5.4%) had moderate-to-severe TR (3+, with TV surgery in 371 [58%]), and 253 (2.2%) had severe TR (4+, with TV surgery in 220 [87%]) on preoperative transthoracic echocardiogram (TTE), assessed in awake patients in all cases. Of the 1,724 with 2+ TR, 91 (5.3%) underwent TV repair concomitant with 830 mitral, 703 aortic, and 191 aortic and mitral valve procedures (Table 1). The TV repair consisted of prosthetic annuloplasty in 64 (70% [Cosgrove-Edwards annuloplasty band in 52, McCarthy-Carpentier in 7, Carpentier-Edwards in 5]), Kay commissuroplasty in 26 (29% [combined with an edge-to-edge procedure in 3]), and edge-to-edge repair in 1 (1.1%). Additional concomitant procedures included coronary revascularization (n = 23), maze procedure (n = 30), closure of a patent foramen ovale or atrial septal defect closure (n = 9), and ascending aorta repair (n = 3).

Preoperative Right-Side and Left-Side Heart Morphology and Function
Preoperative TTE variables were retrieved for propensity-matched patients (see Data Analysis), and 40 de novo measurements were made of right-side and left-side heart morphology and function, with Institutional Review Board approval. Measurements were made off-line using ProSolv CardioVascular Analyzer 3.5 (Indianapolis, IN) according to American Society of Echocardiography guidelines and definitions [6].

Endpoints
Safety
Safety endpoints included in-hospital morbidity and mortality compiled according to The Society of Thoracic Surgeons Adult Cardiac Database definitions (see: http://www.ctsnet.org/file/rptDataSpecifications252_1_ForVendorsPGS.pdf).

Clinical Effectiveness
Clinical effectiveness endpoints included TR grade after surgery before discharge and its progression in the intermediate term, TV-related reoperation after index procedure, New York Heart Association (NYHA) functional status, and long-term survival.

Echocardiography
Postoperatively, 166 of the 182 propensity-matched patients (see Data Analysis) had a total of 343 TTEs performed with TR grade assessed in the echocardiographic laboratory according to American Society of Echocardiography criteria, including evaluation of the color TR jet area (right atrial area, vena contracta, proximal isovelocity surface area) and hepatic vein flow reversal. Although TR severity ranged from 1+ to 4+, TR grades 3+ and 4+ were combined in analysis because of small numbers.

Patient Follow-up
The TV-related reoperations, NYHA class, and vital status were assessed by routine active follow-up at 2 and 5 years postoperatively, and at 5-year intervals thereafter, using an Institutional Review Board–approved mailed questionnaire or telephone follow-up script. Of the 1,724 patients, 411 have incomplete follow-up. In all, 5,859 patient-years of systematic active anniversary-type follow-up (median 3.0) data for reoperative events were available for analysis, with 10% of patients followed more than 6.8 years. For vital status, these data were supplemented by interrogation on May 27, 2011 of the Social Security Administration Death Master File [7]. Combined cross-sectional passive and active follow-up for vital status resulted in 10,650 patient-years (median, 7.1 years) of follow-up data, with 10% of patients followed more than 11 years.

Data Analysis
Factors Associated With TV Repair for 2+ TR
Multivariable logistic regression was used to identify factors associated with performing TV repair for 2+ TR. Variables considered in this analysis are listed in the Appendix. Bagging was used to identify reliable predictors with random resampling and automated stepwise selection (entry criterion of p 0.10, retention criterion p 0.05) [8]. Variables or clusters of variables that entered 50% of 1,000 models were chosen for the final model. A measure of reliability accompanies each variable in the analysis and should be interpreted as the probability that p is 0.05 or less.

View larger version (12K): [in this window] [in a new window]   Fig 1. Propensity score distribution and results of propensity score matching. (A) Mirrored histogram of distribution of propensity scores. No tricuspid valve (TV) repair group appears above the horizontal line of zero and tricuspid valve repair group below it. Dark bars indicate distribution of propensity scores of matched patients. (B) Covariate balance for selected variables before matching (filled triangles) and after matching (filled squares). Values on the horizontal axis represent the percent standardized difference [1] between tricuspid valve repair and no-repair groups. Data from Austin and Mamdani [29]. (AV = atrial valve; MV = mitral valve; RV = right ventricular.)

The TR grade across time was estimated by longitudinal repeated-measures analysis (PROC MIXED; SAS Institute, Cary, NC). Because of the ordinal nature of TR grade, it was assumed to have a multinomial distribution. Using this assumption, a longitudinal cumulative logit model was used to model the temporal trend of TR.

Freedom from TV-related reoperation and survival after index valve surgery was estimated nonparametrically by the Kaplan-Meier method and parametrically by multiphase hazard methodology [10]. (For additional details, see: http://my.clevelandclinic.org/professionals/software/hazard/default.aspx.)

The NYHA class across time was estimated by using a generalized nonlinear mixed model with temporal decomposition of phases (PROC NLMIXED; SAS Institute) [11].

Presentation
Continuous variables are summarized by mean ± SD or by median and 15th and 85th percentiles, consistent with ± 1 SD. Categorical data are summarized by frequencies and percentages. Model coefficients are accompanied by ± 1 SE. Survival and longitudinal point estimates are presented with asymmetric 68% confidence limits (CL) equivalent to ± 1 SE.

	Results

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
Reasons for and Factors Associated With TV Repair
Nonmutually-exclusive reason for TV repair, abstracted from operative reports, was pulmonary hypertension in 35 patients (38%), right ventricular (RV) dilation or dysfunction in 25 (27%), anular dilation in 20 (22%), and avoidance of yet another future reoperation in 12 (13%). In 23 patients (25%), no reason was documented. Patient factors associated with repair were female sex (p = 0.0001), elevated bilirubin (p = 0.02), prior mitral valve procedure (p = 0.004), concurrent mitral valve procedure (p < 0.0001), and atrial ablation procedure (p = 0.003). Echocardiographic factors associated with repair included larger right and left ventricles and greater TV tethering height (Table 2).

View larger version (22K): [in this window] [in a new window]   Fig 2. Bubble plot of predischarge grade of tricuspid regurgitation (TR) compared with preoperative level 2+ among propensity-matched patients stratified by undergoing tricuspid valve (TV) repair or not.

View larger version (14K): [in this window] [in a new window]   Fig 3. Percent of propensity-matched patients in each grade of tricuspid valve (TV) regurgitation (TR) postoperatively: (A) TR 0; (B) TR 1+; (C) TR 2+; (D) TR 3+/4+. Horizontal lines are point estimates enclosed within dashed 68% confidence bands. These have been adjusted for repeated measures. Symbols represent data grouped (without regard to repeated measurements) within time frames to provide a crude verification of model fit.

NYHA Class After Surgery
Among matched patients, approximately 70% who underwent TV repair were in NYHA class I after surgery, and this was sustained over 6 years of follow-up. Among patients without TV repair, approximately 60% were in NYHA I early after surgery, drifting to 55% over 6 years (Fig 4).

View larger version (12K): [in this window] [in a new window]   Fig 4. Percent of propensity-matched patients in each New York Heart Association (NYHA) functional class, depicted from operation to 6 years postoperatively: (A) NYHA class I; (B) NYHA class II; (C) NYHA class III; (D) NYHA class IV (depiction is as in Figure 3). (TR = tricuspid regurgitation; TV = tricuspid valve.)

View larger version (14K): [in this window] [in a new window]   Fig 5. Survival of propensity-matched patients with or without a tricuspid valve (TV) repair. Each symbol represents a death, vertical bars 68% confidence limits, and numbers in parentheses patients remaining at risk. Solid lines enclosed within dashed 68% confidence bands are parametric survival estimates.

	Comment

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

For many years, the concept that secondary TR decreases after mitral valve surgery alone has largely been accepted. This has led to a conservative nonsurgical approach to functional TR [1, 17, 18]. However, untreated functional TR can persist or worsen despite correction of the left-sided valve pathology [4, 5, 19], leading to changes in RV morphology and function and symptoms and signs of right-side heart failure [20]. Reoperation in this setting is associated with substantial hospital mortality [21]. That raises the question of whether an opportunity has been missed to address TR earlier, at time of left-sided valve surgery.

Principal Findings
Heretofore, surgical correction of 2+ TR has not been common practice in our center—91 of 1,724 patients (5%). During the timeframe of this study, less invasive surgery became the dominant approach to left-sided heart valve disease [22-24]. Less invasive approaches may focus attention on a single valve, ignoring moderate TR, even though the TV is accessible.

When repair was performed, surgeons documented RV morphologic changes, such as anular and RV dilation, RV dysfunction, and pulmonary hypertension, all harbingers of progression of right-sided disease [25]. Although not all components of a surgeon's decision to repair the TV were explicitly documented, this study clarifies several of the criteria. First, patients with clinical evidence of RV impairment, with documented biomarkers, tended to undergo TV repair. Second, surgical observations of morphologic changes of right-heart structures, both by preoperative echocardiography and direct vision, including of TV anular dilation and right atrial and RV enlargement, were often documented. Third, our retrospective measurements of heart structure and function identified the combination of right-side and left-side heart dilation with TV tethering as being strongly related to the surgical decision to repair the TV. Fourth, repair was sometimes performed to avoid subsequent reoperation, because of high risk [22]. This was the case for 12 patients who underwent concomitant left-sided heart valve reoperations at time of TV repair.

Female sex, a planned mitral valve versus aortic valve procedure, presence of atrial fibrillation with planned ablation procedure for atrial fibrillation, and elevated bilirubin emerged as factors associated with TV repair. These factors mirror those identified by others as predisposing patients to development of more severe TR in left-sided heart valve disease [26, 27].

Safety
Adding TV repair did not importantly increase surgical times. Complications with or without repair were infrequent and similar except, curiously, for more strokes in the TV repair group. These 5 patients were all in atrial fibrillation preoperatively. One also had experienced two previous strokes. Another had transient memory loss without neuromotor sequelae; head computed tomography scan revealed focal ischemic changes. Two had debridement of extensive mitral anular calcium. In 1e, who had an anterior right thoracotomy, an aortic endoscopic clamp was used. One patient had a patent foramen ovale. These comorbid and surgical factors seem not to implicate TV repair in the causal chain.

We conclude that performing a TV repair at the time of surgery for left-sided heart valve disease does not jeopardize clinical outcome.

Clinical Effectiveness
Despite repair of left-sided valve pathology, only 20% of patients with 2+ TR who did not have TV repair had no TR postoperatively, compared with more than half after TV repair. Indeed, 39% remained in 2+ TR, compared with 11% after TV repair. Importantly, 15% had worse TR, compared with 7% after TV repair. These levels of predischarge TR were sustained in the midterm in both groups, including the discrepancy in TR between groups. Patients who progressed to 3+ TR during follow-up after TV repair had a Kay repair in 4 cases, edge-to-edge stitch in 1 case, and flexible mitral annuloplasty ring in 1 case. These findings agree with our previous study on long-term outcomes after repair for severe TR secondary to degenerative left-sided valve disease, for which rigid ring annuloplasty provided better midterm and long-term results [28].

Study Limitations
This is a single-institution, nonrandomized clinical experience. There was clearly selection of patients for TV repair, and we used propensity methods to attempt to reduce bias from this. We were limited by number of accessible follow-up echocardiogram studies; the echocardiogram studies used were primarily those of patients routinely followed at our institution, regardless of severity of their condition.

In summary, TV repair for moderate (2+) TR concomitant with surgery for left-sided degenerative heart valve disease is safe, with little penalty in terms of operative time and morbidity, and provides a clinically effective benefit in preventing worsening of TR. Thus, we now question the prevailing conservative strategy of ignoring 2+ TR and recommend a TV procedure, particularly for patients with advanced left-sided degenerative disease requiring mitral valve replacement, and for patients with important RV remodeling and evidence of RV failure. We believe this approach provides an opportunity to prevent further RV remodeling and dysfunction and progression of TR to severe, and to avoid later reoperation.

	Appendix

 

	Discussion

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
DR ROBERT DION (Genk, Belgium): I am puzzled about the grading of tricuspid regurgitation. As you know, the right ventricle and tricuspid valve function are very much dependent on preload. And a grade 3 tricuspid regurgitation can, after a few days of diuretics, come down to grade 1. You told us that some of your colleagues are more aggressive in repairing the tricuspid valve, based on the grading of the tricuspid valve insufficiency, but it is not really reliable. That is why we have tried to find a parameter that is not dependent on preload, namely, the chronic dilation of the tricuspid annulus. So my question is, did you try to correlate the grading of the tricuspid regurgitation with the dimensions of the tricuspid annulus or the right ventricle?

DR NAVIA: That's a great question. I'm aware about the relationship between the right ventricle and the tricuspid annulus dimension and the degree of tricuspid valve regurgitation, as well as the important role that these structures play in the morbidity and mortality of patients with signs and symptoms of right heart failure. Unfortunately, we haven't analyzed all the morphologic and functionally echocardiographic variables of the right heart in this 11-year retrospective study. The only thing we have measured for this presentation is the different grades of TR before and after surgery and the evolution over time by TTE studies performed with TR grade assessed according to standard American Society of Echocardiography criteria, which included evaluation of the color TR jet area (right atrial area, vena contracta, proximal isovelocity surface area), and hepatic vein flow reversal. We are right now analyzing morphologic and functional echocardiographic variables in 91 propensity-matched patient pairs, and the results will be included in the manuscript.

DR DION: It would be nice to measure the dimensions of the annulus and/or the right ventricle in the patients in whom a valve repair was performed, and try to find some correlation.

DR NAVIA: That's what we're doing right now. Regardless, we have always found very difficult to assess the right side retrospectively owing to the enormous attention given to evaluate the left heart, lack of standard ultrasound techniques in imaging the right heart as well as the normal reference values of anatomic size and function; we are measuring in these matched patient pairs the right heart dimension, right atrium and ventricle end systolic area, pressure, and volumes; as well as RV systolic function using several parameters such as TAPSE (tricuspid annular plane systolic excursion), MPI (myocardial performance index), FAC (fractional area change), ET (ejection time), and so forth. Also we measure tricuspid valve systolic and diastolic annular dimension (TV SAD and TV DAD), tethering leaflet height and tethering leaflet area, and so on. So now we are using these parameters in a prospective way in every ultrasound study to better understand and assess right heart measurement and function for a proper therapy.

DR D. JEONG (Seoul, Republic of Korea): I am very pleased with your well-designed paper and nice presentation. I have several questions. First, how many patients underwent reoperations for TR late after successful left 31 cardiac surgery? And I want to know clinical results of those patients.

DR NAVIA: This is a very good question. We have only 3 patients who had reoperation. There was one reoperation 6 days after TV repair, and no more as far as these patients were followed. Therefore, freedom from TV-related reoperation was 98.9%. This was similar to the matched no-repair group in which two TV-related reoperations were performed, one at 1.7 years and the other at 10 years. The message of this paper, actually, of this presentation, is do not lose the opportunity to repair moderate tricuspid valve regurgitation at the time of surgery for degenerative left-side heart valve disease, because provides a clinically effective benefit in preventing worsening of TR and right heart failure, a situation that makes the patient not suitable for reoperation owing to high risk in morbidity and mortality. We believe this approach provides an opportunity to prevent further RV remodeling and dysfunction and progression of TR to severe, and to avoid later reoperation.

DR JEONG: But I think that the period of occurrence of tricuspid regurgitation is long, and your follow-up duration is very short in analyzing these kinds of studies.

DR NAVIA: Correct.

DR JEONG: The 3 patients are not small 32 considering short-term follow-up.

DR NAVIA: You're correct. This is an intermediate follow-up. We don't have echo data for long term follow up. It could be more realistic, to know which are the results of the annular repairs at ten years. But the data we have right now show that repair strategy improves the recurrence of TR after surgery and if you do not surgically address moderate TR at the time of left heart valve surgery, moderate TR remains the same or becomes worse, at least in 54% of the patients. So it's a very important message for moderate TR.

DR JEONG: Second, the atrial fibrillation, as you know, is predictive of occurrence of right TR. So I want to know the success rate of your maze operation in your series and the effect of atrial fibrillation on your TR.

DR NAVIA: This is an interesting question, because as you know long-standing atrial fibrillation promotes increase the size of the right atrium and also the tricuspid annulus. Female sex, a planned mitral valve versus aortic valve procedure, presence of atrial fibrillation with planned ablation procedure for atrial fibrillation, and elevated bilirubin emerged as factors associated with TV repair. These factors mirror those identified by others as predisposing patients to development of more severe TR in left-sided heart valve disease. The success rate of atrial fibrillation treatment in this study was more than 90%.

DR JEONG: The last question is left ventricular diastolic dysfunction, which may play an important role in right heart failure, such as elevated pulmonary artery pressure or including tricuspid regurgitation. So did you check the left ventricular diastolic function at the time of the left-sided surgery?

DR NAVIA: Unfortunately, we do not have the LV diastolic function data of all the patients in our study, so I cannot give you a right answer.

DR THOMAS MACGILLIVRAY (Boston, MA): I have a question. This may be difficult to glean given the nature of the study. It is always difficult to retrospectively try to understand prospective decisions. You mentioned that the charts were reviewed trying to determine from the operative report whether or not to repair the valves. The trouble is that your patient population in the repair group and the not-repair group seem to be the same, or at least very similar. But there was a decision made by the surgeon at the time to repair the valve or not to repair the valve. To then look at the whole patient cohort afterwards and then try to assign which patients were correctly or not correctly managed makes it very difficult. So my question is, were there in these patients any absolute indications to repair the valve, or it was all left up to the surgeon?

DR NAVIA: Obviously, it's a retrospective analysis and the limitation is that, based on operative notes, as I mentioned, nonmutually exclusive reasons for tricuspid valve repair included pulmonary hypertension in 38%, right ventricular dysfunction in 27%, anular dilation in 22%, possible harbingers for future progression of right-sided disease and high-risk reoperation and avoidance of another reoperation in 13%, but it was the surgeon who had the final decision in the operating room, if the tricuspid valve was going to be repaired or not.

DR MACGILLIVRAY: But if I recall your slides correctly, the groups were very similar. Perhaps there was some other difficult to articulate data that differentiated the two groups?

DR NAVIA: Correct, they were very similar, that's why we used propensity matching for fair comparison among them.

	Acknowledgments

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 
This study was supported in part by the Kenneth Gee and Paula Shaw, PhD, Chair in Heart Research (EHB).

	References

Top Abstract Introduction Patients and Methods Results Comment Discussion Acknowledgments References

 

1. Braunwald NS, Ross J, Morrow AG. Conservative management of tricuspid regurgitation in patients undergoing mitral valve replacement Circulation 1967;35:I63-I69.[Medline]
2. Breyer RH, McClenathan JH, Michaelis LL, McIntosh CL, Morrow AG. Tricuspid regurgitation. A comparison of nonoperative management, tricuspid annuloplasty, and tricuspid valve replacement. J Thorac Cardiovasc Surg 1976;72:867-874.[Abstract]
3. Frater R. Tricuspid insufficiency J Thorac Cardiovasc Surg 2001;122:427-429.[Free Full Text]
4. Colombo T, Russo C, Ciliberto GR, et al. Tricuspid regurgitation secondary to mitral valve disease: tricuspid annulus function as guide to tricuspid valve repair Cardiovasc Surg 2001;9:369-377.[Medline]
5. Dreyfus GD, Corbi PJ, Chan KM, Bahrami T. Secondary tricuspid regurgitation or dilation: which should be the criteria for surgical repair? Ann Thorac Surg 2005;79:127-132.[Abstract/Free Full Text]
6. Rudski LG, Lai WW, Afilalo J, et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography J Am Soc Echocardiogr 2010;23:685-713.[Medline]
7. Boyle CA, Decoufle P. National sources of vital status information: extent of coverage and possible selectivity in reporting Am J Epidemiol 1990;131:160-168.[Abstract/Free Full Text]
8. Breiman L. Bagging predictors Machine Learning 1996;24:123-140.
9. Rubin DB. The design versus the analysis of observational studies for causal effects: parallels with the design of randomized trials Stat Med 2007;26:20-36.[Medline]
10. Blackstone EH, Naftel DC, Turner ME. The decomposition of time-varying hazard into phases, each incorporating a separate stream of concomitant information J Am Stat Assoc 1986;81:615-624.
11. Mason DP, Rajeswaran J, Murthy SC, et al. Spirometry after transplantation: how much better are two lungs than one? Ann Thorac Surg 2008;85:1193-1201.[Abstract/Free Full Text]
12. Come PC, Riley MF. Tricuspid anular dilation and failure of tricuspid leaflet coaptation in tricuspid regurgitation Am J Cardiol 1985;55:599-601.[Medline]
13. Sagie A, Schwammenthal E, Padial LR, Vazquez de Prada JA, Weyman AE, Levine RA. Determinants of functional tricuspid regurgitation in incomplete tricuspid valve closure: Doppler color flow study of 109 patients J Am Coll Cardiol 1994;24:446-453.[Medline]
14. Rogers JH, Bolling SF. The tricuspid valve: current perspective and evolving management of tricuspid regurgitation Circulation 2009;119:2718-2725.[Abstract/Free Full Text]
15. Kuwaki K, Morishita K, Tsukamoto M, Abe T. Tricuspid valve surgery for functional tricuspid valve regurgitation associated with left-sided valvular disease Eur J Cardiothorac Surg 2001;20:577-582.[Abstract/Free Full Text]
16. De Bonis M, Lapenna E, Sorrentino F, et al. Evolution of tricuspid regurgitation after mitral valve repair for functional mitral regurgitation in dilated cardiomyopathy Eur J Cardiothorac Surg 2008;33:600-606.[Abstract/Free Full Text]
17. Duran CM, Pomar JL, Colman T, Figueroa A, Revuelta JM, Ubago JL. Is tricuspid valve repair necessary? J Thorac Cardiovasc Surg 1980;80:849-860.[Abstract]
18. King RM, Schaff HV, Danielson GK, et al. Surgery for tricuspid regurgitation late after mitral valve replacement Circulation 1984;70:I193-I197.[Medline]
19. Porter A, Shapira Y, Wurzel M, et al. Tricuspid regurgitation late after mitral valve replacement: clinical and echocardiographic evaluation J Heart Valve Dis 1999;8:57-62.[Medline]
20. Fukuda S, Gillinov AM, McCarthy PM, et al. Determinants of recurrent or residual functional tricuspid regurgitation after tricuspid annuloplasty Circulation 2006;114:I582-I587.[Medline]
21. McCarthy PM, Bhudia SK, Rajeswaran J, et al. Tricuspid valve repair: durability and risk factors for failure J Thorac Cardiovasc Surg 2004;127:674-685.[Abstract/Free Full Text]
22. Cosgrove DM, Sabik JF, Navia JL. Minimally invasive valve operations Ann Thorac Surg 1998;65:1535-1539.[Abstract/Free Full Text]
23. Cosgrove DM, Sabik JF. Minimally invasive approach for aortic valve operations Ann Thorac Surg 1996;62:596-597.[Abstract/Free Full Text]
24. Navia JL, Cosgrove DM. Minimally invasive mitral valve operations Ann Thorac Surg 1996;62:1542-1544.[Abstract/Free Full Text]
25. Dreyfus GD, Chan KM. Functional tricuspid regurgitation: a more complex entity than it appears Heart 2009;95:868-869.[Free Full Text]
26. Varadarajan P, Pai RG. Tricuspid regurgitation in patients with severe mitral regurgitation and normal left ventricular ejection fraction: risk factors and prognostic implications in a cohort of 895 patients J Heart Valve Dis 2010;19:412-419.[Medline]
27. Singh JP, Evans JC, Levy D, et al. Prevalence and clinical determinants of mitral, tricuspid, and aortic regurgitation (the Framingham Heart Study) Am J Cardiol 1999;83:897-902.[Medline]
28. Navia JL, Nowicki ER, Blackstone EH, et al. Surgical management of secondary tricuspid valve regurgitation: annulus, commissure, or leaflet procedure? J Thorac Cardiovasc Surg 2010;1391473-82.e5.
29. Austin PC, Mamdani MM. A comparison of propensity score methods; a case-study estimating the effectiveness of post-MI statin use Stat Med 2006;25:2084-2106.[Medline]

This article has been cited by other articles:

				V. Katsi, L. Raftopoulos, C. Aggeli, I. Vlasseros, I. Felekos, D. Tousoulis, C. Stefanadis, and I. Kallikazaros Tricuspid regurgitation after successful mitral valve surgery Interact CardioVasc Thorac Surg, July 1, 2012; 15(1): 102 - 108. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Jose L. Navia Nicolas A. Brozzi Chanapong Kittayarak Edward R. Nowicki Eugene H. Blackstone Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Navia, J. L. Articles by Blackstone, E. H. Search for Related Content PubMed PubMed Citation Articles by Navia, J. L. Articles by Blackstone, E. H. Related Collections Valve disease