Patients and Methods

After our Institutional Ethics Committee's approval of this retrospective study, we searched our hospital's database for demographic, preoperative, intraoperative, and postoperative data on patients with TR. Of 507 who had undergone TV surgical repair at our hospital from January 2009 through December 2014, 48 also underwent implantation of expanded PTFE (e-PTFE) neochordae. These 48 patients had undergone transthoracic echocardiography (TTE) preoperatively and before discharge from the hospital, as well as intraoperative transesophageal echocardiography (TEE) before and after repair.

Surgical Techniques

All patients underwent median sternotomy. All procedures were performed with use of cardiopulmonary bypass (CPB) and moderate hypothermia. After an oblique right atriotomy was performed for optimal exposure, MV repair and concomitant procedures were completed through a transseptal approach. Subsequently, the structure and function of the TV were evaluated by means of intraoperative saline injection leak-testing. We clamped the pulmonary artery while the RV was filled with saline solution. Secondary TV regurgitation was corrected by ring annuloplasty or bicuspidization (Kay annuloplasty). Our strategy for TV repair was to perform Kay annuloplasty in patients who had a tricuspid annular diameter ≥40 mm and mild TR. If TR was moderate or severe, we performed ring annuloplasty.

In performing tricuspid ring annuloplasty, we determined the appropriate ring size from the surface area of the leaflet tissue attached to the chordae arising from the anterior papillary muscle. Tricuspid valve bicuspidization is accomplished by plicating the annulus along the posterior leaflet.⁷ We used 5-0 e-PTFE sutures when replacing the chordae tendineae. The e-PTFE neochordae were implanted by initially attaching the suture to the head of the papillary muscle and subsequently passing it through the free margin of the prolapsed TV leaflet, from the ventricular side to the atrial side. The length was adjusted by using the nonprolapsed leaflet as a guide. Finally, more than 10 knots were used to tie the suture. In patients with rheumatic TV disease, nerve hooks were used to analyze the TV morphology and to detect valvular lesions (Fig. 1).

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Commissurotomy with division of fused chordae and resection of secondary chordae was frequently performed as the initial procedure. Primary chordae resection was performed in some patients to enable leaflet mobilization. We used artificial neochordae in these patients to repair prolapsed segments that resulted from the primary chordae resection. We evaluated TV competence after annuloplasty by filling the RV with saline solution and observing leaflet coaptation. We used TEE for our final evaluation of the repair after the patients were completely weaned from CPB. When TEE showed suboptimal results, a second cross-clamp was placed to achieve satisfactory repair.

All patients received anticoagulation for 3 months to maintain an international normalized ratio between 2 and 2.5. Lifelong anticoagulation was prescribed for patients who had atrial fibrillation (AF) or mechanical prostheses.

Results

Table I documents the preoperative characteristics of the 48 patients. The median age was 62 years (range, 4–77 yr), and 24 (50%) of the patients were women. The mean preoperative left ventricular ejection fraction was 0.59 ± 0.06.

Table I. Preoperative Characteristics of the 48 Patients

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Thirty patients (63%) were in New York Heart Association (NYHA) functional class III, and 11 (23%) were in class II. Preoperatively, 22 patients had AF. Cardiovascular comorbidities included MV disease in 42 patients and secundum atrial septal defects in 5 (Fig. 2). Table II shows the intraoperative data.

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Table II. Intraoperative Data of the 48 Patients

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Tricuspid Valve Disease and Repair

Table III lists the types of TV disease identified during surgery. Nineteen patients had anterior leaflet prolapse; 6 had involvement of both the posterior and septal leaflets. Commissural fusion was identified in 11 patients.

Table III. Types of Tricuspid Valve Disease in the 48 Patients

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Patients with annular dilation and prolapse underwent bicuspidization (n=13) or ring annuloplasty (n=33) in addition to neochordae implantation and other techniques (commissurotomy or resection of chordae tendineae). Figure 3 shows the distribution of the prosthetic ring sizes.

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In total, 103 chordae were replaced, as follows: 55 in the anterior leaflets of 30 patients, 33 in the septal leaflets of 12 patients, 3 in the posterior leaflets of 3 patients, and 12 in the septal and posterior leaflets of 3 patients.

Follow-Up Findings

Table IV shows the early and late complications after TV repair. Early (<30-d) death occurred in one patient who had low cardiac output syndrome. The mean intensive care unit stay for all patients was 2.9 ± 1.4 days, and mean hospital stay, 9 ± 4 days (Table II). New-onset AF in 6 patients was medically resolved in all cases. Six patients needed inotropic support for longer than 24 hours. One patient had a cerebrovascular accident.

Table IV. Early and Late Morbidity and Death in the 48 Patients

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Late follow-up data were obtained in 47 cases at an average of 44.3 ± 20.2 months postoperatively. One patient died of noncardiac causes. One patient who needed reoperation to treat infective endocarditis underwent mechanical valve replacement 14 months after MV and TV repair.

Repair was satisfactory in all except 5 patients who had moderate TR when discharged from the hospital. The TV repair was successful in 38 patients, who presented with absent or minimal or with mild TR. Seven patients (including 3 who had moderate TR at hospital discharge) presented with moderate TR, which was asymptomatic with medical therapy. Four of these patients had undergone Kay annuloplasty in addition to artificial neochordae implantation. We identified left ventricular dysfunction in 4 of the 7 patients who had moderate TR during follow-up. Severe TR developed in 2 patients who had undergone concomitant MV replacement and had left ventricular dysfunction (ejection fraction, ≤0.50). Table V and Figure 4 report the echocardiographic follow-up data of the patients.

Table V. Results of Operation on Tricuspid Regurgitation Grade

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Discussion

Functional TR, which results mainly from dilation of the tricuspid annulus secondary to RV enlargement, is the most prevalent type of TV insufficiency.⁴ Later in the course of the disease, tethering of the tricuspid leaflets due to displacement of the papillary muscles may also contribute to TR.¹⁰ The principles of treatment for secondary TR include correcting increased RV afterload (by treating left-sided heart disease and optimizing left ventricular function) and correcting tricuspid annular dilation and dysfunction, usually by TV annuloplasty.⁴ Traditionally, the primary goal of surgical treatment for secondary TR has been to correct tricuspid annular dilation by means of suture annuloplasty or ring annuloplasty. Most suture annuloplasty techniques are modified versions of Kay's bicuspidization technique or De Vega annuloplasty, which consist of plicating the posterior and anterior annulus.^7,11 In prosthetic ring annuloplasty, the annulus is permanently fixed in a systolic position, and the physiologic shape of the TV is restored.¹² However, none of these techniques has consistently eliminated functional TR.

The recurrence rate of substantial tricuspid insufficiency after tricuspid annuloplasty ranges from 8% to 15% as early as one month after surgery.^9,13 Dreyfus and colleagues¹⁴ reported excellent outcomes, with only a 2% recurrence rate after tricuspid ring annuloplasty for functional TR. However, this series did not include patients with severe TR or severe leaflet tethering, in whom reported recurrence rates have ranged from 15% to 30%.^9,15 It has long been recognized that ring annuloplasty is unlikely to successfully treat severe leaflet tethering resulting in TR; several repair techniques have been suggested for these cases, including suture bicuspidization of the TV, and the clover technique.^16,17 Aoyagi and colleagues¹⁸ reported a TR recurrence rate of 11.6%, a 10-year survival rate of 88.2%, and a freedom-from-reoperation rate of 97.6% after modified De Vega annuloplasty. However, when functional TR results from both severe annular dilation and leaflet tethering, annuloplasty alone is unlikely to be successful.⁸ In these circumstances, several additional techniques have been proposed to achieve effective, durable repair. Augmentation of the anterior leaflet with autologous pericardium has been used in patients with substantial tethering, and different procedures have been combined with annuloplasty in the presence of prolapse or flail, including chordae replacement, leaflet resection, chordal transposition, and papillary muscle reimplantation.^19–23

During the past 10 years, e-PTFE sutures have been used to replace chordae tendineae, especially in patients with MV prolapse. Reports of artificial chordae tendineae implantation for the treatment of TR regurgitation are sparse. Marin and co-authors²⁴ reported the case of a 72-year-old woman in NYHA class III who underwent successful TV repair with implantation of artificial neochordae; her preoperative echocardiograms revealed severe TV regurgitation caused by prolapse of the anterior leaflet (A1–A2) and annular dilation. Artificial chordal implantation is also used in the repair of traumatic TR, which is associated with chordal disruption, rupture of the anterior papillary muscle, leaflet laceration, and leaflet retraction.^19–21 Tricuspid valve malformations such as papillary muscle elongation and congenital absence of the papillary muscle can also be treated by artificial chordae implantation. Ito and colleagues²⁵ reported the use of artificial chordae to repair isolated congenital TR in a 23-year-old woman. These reports have suggested that artificial chordal implantation is a viable technique for the surgical repair of TR.

To prevent TR recurrence, we use artificial neochordae implantation as an adjunctive procedure to ring or suture annuloplasty, neither of which has proved completely effective in achieving TR repair. Since 2009, we have used artificial chordae to treat TR resulting from annular dilation associated with prolapse or severe tethering of multiple leaflets. If leaflet tethering persists after annuloplasty, we resect the native chordae of the leaflet and replace them with longer artificial neochordae. Lapenna and associates²⁶ used the clover technique to manage multiple prolapse and flail of the tricuspid leaflets in the presence of traumatic or degenerative TR and severe leaflet tethering secondary to advanced RV remodeling. In that series, TR was absent or mild in 55 patients (88.7%), moderate in 6 (9.6%), and severe in one (1.6%).²⁶ In our institution, the size of the prosthetic ring is chosen on the basis of the surface area of the leaflet tissue attached to the chordae arising from the anterior papillary muscle. In our study, prolapse of the anterior or posterior leaflet was observed in 9 patients whose functional TR resulted from the restriction of the tricuspid annular motion by the ring. Ten other patients with functional TR presented with prolapse of one or multiple TV leaflets after Kay annuloplasty. In these complex cases, we used artificial neochordae implantation as an adjunct to annuloplasty, to restore valvular competence and avoid post-repair leak and the need for valve replacement.

Surgical valve repair is now firmly established as the gold standard for valvular heart disease. Some researchers have analyzed the outcomes of surgical treatment for functional TV regurgitation, but reports on patients with organic TV disease predominate in the medical literature.^15,27–29 Surgical repair of rheumatic TV disease often fails because of severe anatomic distortion of the valve apparatus. The results of this procedure are less satisfactory than those of functional TV repair because, in patients with rheumatic TV disease, the durability of repair is compromised by the active and rapidly progressive nature of the disease process. Bernal and colleagues³⁰ reported that 38 patients (25.3%) with rheumatic valvular heart disease needed TV reoperations after mitral and TV repair. Tang and colleagues³¹ obtained favorable outcomes of rheumatic TV repair with use of autologous pericardium; follow-up echocardiograms showed mild regurgitation in 8 patients (25.8%) and moderate regurgitation in one (3.2%). Among other modern techniques for repairing complex TV lesions is edge-to-edge valve plasty, which has been used as an effective adjunct procedure in patients with residual TR.³² Because TV replacement is a high-risk procedure in patients with rheumatic heart disease³³ and is associated with high recurrence of TR, we chose to repair rheumatic TV by implanting artificial neochordae. This procedure was performed in 15 of our patients with rheumatic TV disease. Other techniques, including commissurotomy, leaflet mobilization, annuloplasty, and prosthetic ring implantation, were performed as needed. Primary chord resection was performed in those 15 patients in addition to secondary chord resection because of the thickened chordae. The consequent prolapse of the TV leaflets was corrected by implanting artificial neochordae. Follow-up echocardiograms showed no or mild TR in 9 of the 15 patients. Five patients had moderate TR and were treated medically. One patient had severe TR. Our results suggest that rheumatic pathology plays a role in determining the durability of TV repair.

Upon discharge from the hospital, only 5 of our surviving 47 patients had moderate TR; the remaining 42 had absent or minimal TR or mild TR. Follow-up TTE showed that TR was absent, minimal, or mild in 80.8% of patients. Seven patients (14.9%) had moderate TR, and 2 (4.3%) had severe TR. Our treatment approach might substantially increase the rate of successful repair in difficult cases, such as those described in our study. However, careful intraoperative evaluation of the anatomic lesions underlying TR is necessary to decide if this technique can be applied with a reasonably high probability of success.