Response to Letters Regarding Article “Determinants of Surgical Outcome in Patients With Isolated Tricuspid Regurgitation”
We thank Drs Raikhelkar and Scurlock for their thoughtful review of our article.1 As pointed out, the pathogenesis of tricuspid regurgitation was functional late after left-sided valve surgery in most of our study subjects, and thus our findings may not be directly applicable in tricuspid regurgitation patients with other organic valve diseases. We agree that this is an important limitation of our study. However, because we prospectively enrolled consecutive patients, we believe our data represent the real patient population in tertiary referral center. Further long-term study is needed to determine predictors of surgical outcome in patients with organic valve diseases.
Evaluation of right-ventricular (RV) size and function using echocardiography is difficult because of complex geometry and the limited definition of the endocardial surface caused by heavy trabeculation. In the present study, we employed RV end-systolic area and fractional area change as echocardiographic markers of RV systolic function because they have been well-validated in many previous studies. We made every effort to obtain a true nonforeshortened apical 4-chamber view. In fact, it was much easier to get a true nonforeshortened right ventricle in our patients because they had a large RV replacing cardiac apex. Cardiac magnetic resonance imaging may offer a better assessment of RV volume and systolic function as we have shown recently.2
We also thank Dr Fayssoil for his thoughtful review of our article.1 We agree that tricuspid annular dilation is an important factor in the development of late tricuspid regurgitation. A long-term follow-up study is needed to determine the threshold to perform tricuspid annuloplasty to prevent late tricuspid regurgitation development.
The majority of the patients had valve replacement, and only 8 patients underwent tricuspid repair mainly using De Vega annuloplasty. Therefore, we could not evaluate the impact of repair versus replacement on surgical outcome. There are a couple of reasons for the high rate of replacement in our study population. First, most of our patients had inadequate coaptation mainly due to severe leaflet tethering and annular dilation, in which the success rate of repair is relatively low. Second, >90% of the patients had a prosthetic valve in the aortic or mitral position, and thus the benefit of the repair is partially reduced.
In addition, we could not demonstrate the difference in prognostic impact between the bioprosthetic and mechanical valves. We believe that longer follow-up with a larger study population is needed to answer this question.
None of the patients had persistent atrioventricular block postoperatively, although transient atrioventricular block was observed early after surgery in some of the patients. One patient underwent postoperative permanent pacemaker implantation due to sick sinus syndrome.
Sources of Funding
This study was supported by a grant of the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A080659).
Kim YJ, Kwon DA, Kim HK, Park JS, Hahn S, Kim KH, Kim KB, Sohn DW, Ahn H, Oh BH, Park YB. Determinants of surgical outcome in patients with isolated tricuspid regurgitation. Circulation. 2009; 120: 1672–1678.
Kim H, Kim Y, Park E, Bae J, Lee W, Kim K, Kim KB, Sohn DW, Ahn H, Park JH, Park YB. Assessment of hemodynamic effects of surgical correction for severe functional tricuspid regurgitation: cardiac magnetic resonance imaging study. Eur Heart J. March 16, 2010. DOI: 10.1093/eurheartj/ehq063. Available at: http://eurheartj.oxfordjournals.org/content/early/2010/03/16/eurheartj.ehq063.long. Accessed June 3, 2010.