Functional tricuspid regurgitation (FTR) often occurs in patients with concomitant left sided valve disease characterized by annular dilatation and right ventricular enlargement.1 There is increasing recognition that persistent FTR is a significant cause for reduced long-term survival and should be corrected during left sided valve surgery.2–6 Although several types of tricuspid valve annuloplasty (TVA) have been described,7–11 there is no consensus on the management of FTR. Herein we report our early experience with a modified technique of TVA. This study compared early and midterm outcomes of modified TVA with the traditional Kay annuloplasty in an age, gender and time period, matched patient group.
Between January 2007 and January 2010, 60 patients (29 men and 31 women) with a mean age of (45.3±7.6) years were treated with TVA. The tricuspid regurgitation (TR) was functional and secondary to left sided valve disease in all patients. Patients with rheumatic tricuspid valve disease were excluded from this study. The 60 patients were equally randomized to two groups according to the TVA type: patients in group A received modified annuloplasty and patients in group B received conventional Kay annuloplasty. The severity of TR was graded as not (0), mild (I), moderate (II), moderate to severe (III) and severe (IV) according to the ratio of maximum TR area to right atrial area. Of these 60 patients, 44 received mitral valve replacement, seven received aortic valve replacement and nine received combined mitral and aortic valve replacement. The preoperative regurgitation grade was I in three cases, II in six cases, III in 12 cases and IV in nine cases in group A, and I in two cases, II in eight cases, III in nine cases and IV in 11 cases in group B. Twenty-six patients in group A and 22 patients in group B were in NYHA class III or IV. The study protocol was approved by the Ethics Committee of Nanjing Medical University. The operating procedure was described to all patients who then signed the informed consent before the operation.
The indications for tricuspid annuloplasty were mild TR associated with at least one of the following factors: (1) rheumatic heart disease; (2) the ratio of maximum diastolic tricuspid annular diameter to body surface area greater than 21 mm/m2; (3) dilation of the right heart and inferior vena cava and (4) overload of the right ventricle.12–14 TVA was performed in all patients with TR. All surgical procedures were performed under general anaesthesia through median sternotomy. The ascending aorta and both venae cavae were cannulated to establish a cardiopulmonary bypass using moderate systemic hypothermia. During the operation, the myocardium was protected by intermittent perfusion with cardioplegic solution via the aortic root or the coronary sinus at intervals of 20 minutes. The left sided valve disease was corrected first and then TVA was performed with the aorta unclamped and the heart beating.
A series of 3–0 Ethibond multifilament, mattress sutures was used for annuloplasty. In group A, the clockwise mattress suture was entered along the root of the annulus at the low aspect of the anterior annulus according to the degree of anterior annulus dilation and finally came out of the septal annulus at the upper margin of the coronary sinus. The other end penetrated the anterior annuls vertically from outside to inside at the same level of the first stitch and then penetrated the septal annulus vertically from inside to outside at the upper margin of the coronary sinus. The two needles penetrated through another pad, pulled and knotted until the tricuspid valve orifice could hold 2.5 fingers with the annular diameter about 30 mm (Figure 1). The conventional Kay annuloplasty was sutured from the anteroposterior commissure to the posteroseptal commissure along the posterior annulus by placing a double pledget supported, mattress suture of 3–0 Ethibond and obliterated the posterior leaflet. Special attention was paid to passing the needle deep enough to grasp the fibrous tissue securely.
Tricuspid valve regurgitation, right atrium (RA) diameter and right ventricle (RV) endodiastolic dimension were assessed and measured pre- and post-operatively by echocardiography. The efficacy of annuloplasty was evaluated by intraoperative transesophageal echocardiography.15 The follow-up rate was 54/54 patients who survived three years and did not have ring annuloplasty. Clinical endpoints were ring annuloplasty for failing suture annuloplasty or death.
Statistical analysis was performed using Software R (version 2.4.1, R Foundation for Statistical Computing). All data were expressed as mean±standard deviation (SD) or as percentage. Intergroup comparisons were performed using the unpaired Student's t test for measurement data and the χ2 test for categorical variables. Doppler echocardiographic data during different periods were compared between the two groups by repetitive measure analysis of variance (ANOVA).16 The Kaplan-Meier curves were used to analyse TR recurrence. A P <0.05 was considered statistically significant.
The preoperative patient characteristics are shown in Table 1. There was no statistically significant difference in age, gender, NYHA functional class, ejection fraction (EF) or TR grade between the two groups. Three patients (one in group A and two in group B) who underwent ring annuloplasty using a semirigid Carpentier-Edwards ring for failing suture annuloplasty were excluded from the follow-up study. One patient in group A required early reoperation for mediastinal bleeding. Pulmonary complications were observed in two patients in group B, ventilation associated pneumonia in one patient and pulmonary embolism in the other. Inpatient data included operation time, cardiopulmonary bypass time, ICU stay, mechanical ventilation time and hospital stay (Table 2). There was no statistically significant difference in these parameters between the two groups. All patients were discharged uneventfully. The follow-up time was (32±7) months in group A and (30±7) months in group B. There was no prosthesis related, complication such as prosthetic endocarditis, ring dehiscence or conduction system injury during the follow-up period. There was one late death (pulmonary infection) in group A and two deaths (intractable heart failure and cerebral haemorrhage) in group B. No patient required late reoperation after discharge from the hospital. The latest follow-up visit (February 2012) showed that NYHA functional class had improved significantly in all surviving patients. Twenty-six patients in group A improved to NYHA class I and two to class III. Twenty-three patients reached class I and three class II in group B. In group A, the mean TR grade was 2.90 before operation, 0.53 at postoperation day 9, 0.55 at 6 months, 0.66 at 12 months, 0.68 at 24 months and 0.71 at 36 months. In group B, the mean TR grade was 2.97 before operation, 0.48 at postoperation day 9, 0.52 at 6 months, 0.71 at 12 months, 0.83 at 24 months and 0.92 at 36 months. The mean postoperative regurgitation grade in the modified Kay group was lower than that in the conventional Kay group at 12, 24 and 36 months (Figure 2), although there was no statistically significant difference. According to the latest clinical records, the postoperative regurgitation grade in group A was 12 cases in 0, 13 in I, two in II and one in III. By comparison, group B has 10 cases in 0, 11 in I, three in II, one in III and 1 in IV. TR increased by more than two grades in twelve patients in group A, but in only eight patients in group B.
Postoperative TR grade II, III and IV were defined as recurrent TR. Three of 28 patients in group A and five of 26 patients in group B developed recurrent TR during the three years of follow-up. Freedom from recurrent TR in both groups is shown in Figure 3. Patients in group A had higher freedom from recurrent TR than those in group B during each postoperative follow-up period.
Colour Doppler echocardiography data before operation, at postoperative day 9 and during the follow-up periods are listed in Table 3. Postoperative and follow-up RA diameter, RV endodiastolic dimension and TR area decreased obviously compared with those before operation in both groups. Comparing RA diameter change before and after operation in both groups showed no significant difference. RV endodiastolic dimension and TR area at postoperative day 9 and during the follow-up periods decreased more in group A as compared with those in group B.
FTR occurs mainly in patients with concomitant left sided valve disease, leading to tricuspid annular dilatation and tricuspid valve leakage during systoles even in the presence of normal leaflets and chordae tendinae.17 Once the tricuspid annulus is dilated, its size cannot spontaneously return to normal and may continue to dilate further.18 Persistent FTR has been increasingly recognized as a significant marker for long-term survival and should be corrected when left sided valve surgery is performed.
Several basic types of tricuspid annuloplasty have been reported in recent years. These suturing methods mainly focus on shortening the annulus and resolving the incomplete tricuspid valve coaptation. If properly applied, they can achieve the desired results. The tricuspid valve has a D shaped annulus and its chronic changes of annulus dilatation are not uniformly distributed. The straight sided, annulus being the base for the septal leaflet is hardly affected by dilatation. The free mural annulus has more expanding capability. An increased length of the mural annulus occupies a dominant position when annular dilatation occurs and this forms the dominant mechanism of FTR.19,20 Regurgitation often occurs primarily at the posteroseptal commissure, for the posterior annulus has the greater expansion and the papillary, chordae tendinae of the posterior leaflet has a weaker pulling force.21
Kay described the technique of suture bicuspidization to correct TR. The figure eight suture, procedure replicating the posterior leaflet is known as reduction annuloplasty and is relatively simple, while it changes the natural anatomy and the physiological state of the annulus. Compared to the Kay method, the modified method is a type of remodelling annuloplasty by shortening the dilated annulus without obliterating the posterior leaflet yet retaining the nonplanar shape of the tricuspid valve, so it can maintain the posterior leaflet coaptation function during the systolic process. It may also provide more normal stress distribution to the leaflet, thus saving the posterior leaflet.
In our surgical procedure, three patients underwent ring annuloplasty using a semirigid Carpentier-Edwards ring for failing suture annuloplasty, in whom the tricuspid annular diameter was dilated to greater than twice the normal size. Other surgical options should be considered for high risk of repair failure.22 Ring annuloplasty was not one of our usual surgical procedures until 2009 in view of costs to the patient.
Changes in preoperative and postoperative TR grade in Figure 2 showed marginal difference between the two groups at 36 months. Significant differences of postoperative data, yearly follow-up and preoperative RV endodiastolic dimension and TR area between the two groups showed that the echocardiographic indexes were advantageous in group A. Although the follow-up TR grades were marginally better in group A, that does not prove that the modified method is better than the conventional Kay annuloplasty. There are at least three reasons for this. Dreyfus et al5 reported that tricuspid insufficiency may persist or recur and produce persistent continued morbidity: persistence of the rheumatic situation may impair the cardiac muscle in a fibrotic manner, leading to irreversible impairment of the tricuspid valve annulus. Another study by Porter et al23 also demonstrated that the haemodynamic basis of the right ventricle and tricuspid valve annulus dilation may continue to exist after operation, thus forming a vicious cycle. In addition, the echocardiographic data obtained from different studies are subject to significant selection and ascertainment bias.24 Our study did not include the influence of atrial fibrillation (AF) on TR. The latest research shows that severe FTR occurs in older patients with chronic AF because of marked right atrial and right ventricular dilation and enlargement of the tricuspid annulus.25,26 So, further studies including AF status are needed to confirm the efficacy of the modified annuloplasty technique. One of our recurrent TR patients died from intractable heart failure and another from cerebral haemorrhage. Although the rest of the recurrent TR patients now have good heart function, further follow-up and larger clinical series are required to establish the long-term stability of this repair technique.
The modified annuloplasty can achieve the same ideal result as Kay annuloplasty at least during the first three years postoperation. Differences in postoperative yearly follow-ups and preoperative, RV, endodiastolic dimension and TR area as well as the echocardiographic indices between the two groups suggest that the modified Kay annuloplasty technique is advantageous as compared with the conventional one. Although recurrent TR occurred in both groups, the follow-up grades were obviously better in the modified Kay annuloplasty group. It could be considered as an option for the correction of functional TR due to simplicity and lower expense.
The authors would like to be grateful to all individuals who voluntarily participated in the study and Dr. XIE Xue-ying (Department of Biomedical Engineering, Southeast University, Nanjing, China) for her insightful suggestions on the manuscript.
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