Asian Cardiovasc Thorac Ann 2006;14:382-386
© 2006 Asia Publishing EXchange Ltd
Mitral Valve Annuloplasty With Carpentier-Edwards Physio Ring: Mid-term Results
Daniel TL Chan, MBBS,
Clement SW Chiu, FRCS,
Lik-Cheung Cheng, FRCS,
Timmy WK Au, FRCS
Cardiothoracic Surgical Unit, Grantham Hospital, Hong Kong, China
For reprint information contact: Timmy WK Au, FRCS Tel: 852 2518 2636 Fax: 852 2553 3436 Email: auwingkuk{at}yahoo.com.hk, Cardiothoracic Surgical Unit, Grantham Hospital, Hong Kong, China.
 |
ABSTRACT
|
|---|
The mid-term results of mitral valve repair with the Carpentier-Edwards Physio annuloplasty ring were assessed in 97 consecutive patients in a single tertiary-referral cardiothoracic surgical center. The mean follow-up time was 3.9 years (range, 1 month to 8.9 years). Most patients were in functional class II and III before the operation. Ejection fraction was < 40% in 8 patients. Causes of mitral regurgitation included degenerative disease (66%), infective endocarditis (13.4%), rheumatic disease (10.3%), and ischemic heart disease (9.3%). Thirty-day mortality was 2.1%. Actuarial survival and freedom from re-operation at 8 years were 91% and 90.8%, respectively. The only significant risk factor for re-operation was residual mitral regurgitation. Four patients suffered thromboembolic complications, giving an overall event-free survival of 93% ± 3.7% during the follow-up period. The Carpentier-Edwards Physio ring provides safe and effective repair of mitral regurgitation on mid-term follow-up.
|
INTRODUCTION
|
|---|
Mitral valve (MV) repair is now established as the surgical strategy of choice over prosthetic valve replacement for mitral regurgitation (MR), when technically feasible. Annuloplasty is a key element in successful repair because MR is typically associated with annular deformation that requires an annuloplasty ring for remodeling. Clinical studies have confirmed better long-term results when an annuloplasty ring is used.1–4 There are many types of annuloplasty ring available, broadly classified as rigid, soft, and semi-rigid. The Carpentier-Edwards Physio ring (Edwards Lifesciences, Irvine, CA, USA) is one of the new generation of semi-rigid rings designed to provide better physiological function after annuloplasty. It features a flexible posterior part and a saddle-shaped anterior part to reduce interference with the normal systolic movement of the mitral annulus whilst still maintaining the rigid annular transverse diameter required for remodeling.5 Although previous studies have demonstrated the feasibility and efficiency of repair with the Physio ring, only a few have reported mid- and long-term results.6–8
The aim of this study was to evaluate the mid-term results of annuloplasty with this ring.
|
PATIENTS AND METHODS
|
|---|
Ninety-seven consecutive patients underwent MV repair using the Carpentier Edwards Physio ring at the Grantham Hospital in Hong Kong between 1st July 1995 and 31st March 2004. Ours is a tertiary referral, university teaching hospital. Preoperative clinical data are shown in Table 1
. The mean age of the patients was 56 years (range 23 to 78 years). Most were in New York Heart Association (NYHA) functional class II and III before the operation. Fifty patients had one or more comorbidities. All patients with atrial fibrillation (AF) were put on warfarin preoperatively. The etiology of MR is shown in Figure 1. All patients were assessed preoperatively by clinical examination, blood tests, chest radiography, and echocardiography; coronary angiography was performed in selected patients. All patients were diagnosed with severe MR before surgery. The definitive etiology was based on the pathology report of the excised leaflet or echocardiographic characteristics.
All operations were performed with standard ascending aortic and bicaval cannulation, and hypothermic (30°C–32°C) cardiopulmonary bypass with intermittent blood cardioplegia. The techniques of MV repair and concomitant procedures are listed in Table 2. Intraoperative transesophageal echocardiography was routinely performed by a cardiac anesthetist. Three patients who had to be put back on bypass and converted to MV replacement due to an unsatisfactory repair were excluded from this study. Postoperatively, all patients had routine transthoracic echocardiography on postoperative day 5 to 7. If clinically stable, they were transferred to the referring cardiologist for long-term out-patient follow-up.
Follow-up data were retrieved for all 97 patients from the inter-hospital computerized clinical database used by all government hospitals in Hong Kong. Follow-up echocardiogram was performed within 6 months of data collection in 84 patients, and within 2 years in the other 13. Data were supplemented by telephone interviews with the patients regarding their clinical status and any complications requiring hospitalization.
For data analysis, the chi-squared test or Fisher’s exact test were used for categorical data. The Kaplan-Meier method and the log-rank test were used for time-dependent data. A p-value of less than 0.05 was considered significant.
|
RESULTS
|
|---|
On routine echocardiography performed on postoperative day 5 to 7, no MR was found in 34 patients, 42 had trivial MR, and 21 had mild MR. Nineteen patients suffered one or more complications (Table 3); the most frequent was renal dysfunction, defined as a peak creatinine > 200 mmol·dL–1, followed by cardiac complications including inotropic support with 2 agents for 2 days and arrhythmias requiring pharmacological and/or electrical cardioversion. The 30-day mortality was 2.1% (2/97 patients). Preoperative, perioperative, and postoperative factors were analyzed (Table 4). Poor left ventricular function (defined as an ejection fraction < 40% on echocardiography), advanced NYHA class, preoperative renal failure, and a concomitant operation were found to be significant risk factors for early mortality (Table 4).
The mean follow-up time was 3.9 years, ranging from 1 month to 8.9 years. Follow-up data were available for all 97 patients. On mid-term follow-up, 21% of patients were in NYHA class I and 62.4% were in class II. The other 16.6% remained in class III or above. Echocardiography on mid-term follow-up showed that 13.8% of patients had no residual MR, 57.5% had mild MR, and 28.8% had moderate MR. Six patients (6.2%) required re-operation. One developed cardiac arrest soon after the operation, which was believed to be due to mitral stenosis causing low cardiac output after placement of a size 28 ring. After emergency valve replacement, the patient was discharged uneventfully. One patient had ring dehiscence and developed moderate MR on the postoperative echocardiogram, requiring re-operation. The other 4 patients had progressive increases in MR as well as symptoms on follow-up. All of them underwent MV replacement at a mean of 2.3 years from the first operation.
The freedom from re-operation after MV repair with the Physio ring at 4 years and 8 years was 93.8% ± 2.3% and 90.8% ± 1.9%, respectively (Figure 2). Amongst all clinical variables, only postoperative residual MR was significantly associated with re-operation ( p = 0.031). The method of repair or etiology of MR did not affect future risk of re-operation (Table 5). Subgroup analysis of the degree of residual MR was performed (Figure 3). Only one of 34 (2.9%) patients in the nil MR group required re-operation, and 8-year freedom from re-operation was 93.9% ± 4.3%. In the trivial MR group, 2 of 42 (4.8%) patients required re-operation; 8-year freedom from re-operation was 93.9% ± 4.3%. In the mild MR group, 3 of 21 (14.3%) patients required re-operation; 8-year freedom from re-operation was 83.8% ± 8.7%. Correlation of severity of MR with the risk of re-operation was found to be statistically significant by log-rank test ( p = 0.031).
View larger version (8K):
[in this window]
[in a new window]
|
Figure 3. Freedom from re-operation for residual mitral regurgitation (MR) at 8 years. For nil MR: 90.2% ± 6.6% at 4 years and 83.8% ± 8.7% at 8 years. For trivial MR: 97.6% ± 2.4% at 4 years and 93.9% ± 4.3% at 8 years. For mild MR: 100% ± 0% at 4 years and 93.9% ± 4.3% at 8 years.
|
|
The overall actuarial survival was 93.6% at 4 years and 91% at 8 years. Diabetes mellitus and hypertension were found to be independent risk factors for late mortality ( p < 0.05). Four patients (4.1%) had thromboembolic events requiring hospitalization: 3 had a transient ischemic attack and one had a minor stroke. No patient required hospitalization for bleeding complications. The overall event-free survival was 93% ± 3.7% (Figure 4). No risk factors for thromboembolic events were identified by multivariate analysis.
Seven of 31 (22.6%) patients previously in AF reverted to sinus rhythm postoperatively. Five of them had sinus rhythm at the time of discharge and 2 were noted to be in sinus rhythm after 3 months; all remained in sinus rhythm at the most recent follow-up. No significant factor was found for the reversion. There were 39 patients still taking warfarin during follow-up; the period of warfarin treatment ranged from 4 months to 1.2 years.
|
DISCUSSION
|
|---|
The Physio annuloplasty ring was conceived by Carpentier in 1969.5 Its design permits dynamic change in the annulus during systole whilst maintaining annular remodeling.5,6 However, the importance of maintaining annular dynamics remains unclear and the choice of ring depends mainly on the surgeon’s preference and experience. Animal studies demonstrated no difference in annular size and motion between the Physio ring and rigid or flexible rings.9–12 There have been few studies reporting the long-term results of mitral annuloplasty using the Physio ring. Carpentier and colleagues5 published their results in 1995, showing that in 137 patients followed up for 18 months, only 6.8% had residual mild MR and none required re-operation. Kurosawa and colleagues8 also had excellent results in a series of 30 patients, with none requiring redo surgery and only 3.4% with residual MR at 6 months. Sousa and colleagues7 found that 2 of 100 patients required re-operation for systemic anterior motion following mitral annuloplasty, and 15 had mild residual MR at 19 months. Raffoul and colleagues6 reported the longest follow-up results at 23 months; they had no re-operations in 190 patients, but 10.5% had mild MR on follow-up. In other studies, re-operation-free survival at 10 years of 82% to 94.2% has been reported.13–16 Our mean follow-up was 3.9 years and the freedom from re-operation of 90.8% at 8 years confirms that the Physio ring provides durable and effective annuloplasty for MV repair.
Most patients who required re-operation had undergone valve repair in the early phase of this series. Techniques such as chordal shortening and artificial chordae made from Prolene sutures are no longer used in our institute, and are regarded as inferior techniques.1 There was no evidence of mitral stenosis as the cause of cardiac arrest in one of the redo patients. However, a size 28 prosthesis was inserted after excising the leaflet and no other cause of low cardiac output was identified. Previously identified risk factors for re-operation following MV repair include anterior MV prolapse, residual MR, failure to perform annuloplasty, chordal shortening, and rheumatic etiology.1,4,13,16 However, our study suggests that the etiology of MR and the style of repair do not contribute significantly to re-operation risk. Only residual MR significantly increased the re-operation rate in our patients. Intraoperative testing by saline injection and transesophageal echocardiography are important to ensure effective repair before coming off bypass. If necessary, bypass should be re-instituted and revision of the repair or even valve replacement should be carried out. This is the policy adopted in our unit. In the case of more than mild residual MR in the post-repair echocardiogram, further action should be taken. Three patients in this series had MV replacement for this reason; repair was not attempted again because of long bypass time and expected repair failure.
Freedom from thromboembolic complications has been reported to range from 82.5% to 94% at 10 years.14–16 We could not identify any risk factors for thromboembolic complications. There was no correlation with AF or the size of annuloplasty ring. No surgery for AF was performed during the study period. Only atrial plication was carried out if the left atrium was enlarged or if the patient was considered at high risk of thromboembolism. Although AF did not contribute to early postoperative mortality, it was the main reason for continuing warfarin. Surgery alone had a low rate of conversion of AF to sinus rhythm. The time to stop warfarin after repair is difficult to assess. As different referring cardiologists would have different protocols, the data cannot be used meaningfully.
We acknowledge that our study has limitations: it was a retrospective case series, and the patient cohort was heterogeneous in terms of etiology and style of MV repair. Moreover, there were differences in left ventricular function, ranging from normal to severely impaired. Nevertheless, this study confirms that the Physio ring offers effective and durable annular remodeling on mid-term follow-up. Further prospective studies are warranted to define long-term benefits or problems with the Physio ring, and to compare it with other types of annuloplasty ring.
Presented at the 13th Annual Meeting of the Asian Society for Cardiovascular Surgery, Chiang Mai, Thailand, February 4–8, 2005.
|
REFERENCES
|
|---|
- Gillinov AM, Cosgrove DM, Blackstone EH, Diaz R, Arnold JH, Lytle BW, et al. Durability of mitral valve repair for degenerative disease. J Thorac Cardiovasc Surg 1998;116:734–43.[Abstract/Free Full Text]
- Braunberger E, Deloche A, Berrebi A, Abdallah F, Celestin JA, Meimoun P, et al. Very long-term results (more than 20 years) of valve repair with carpentier’s techniques in nonrheumatic mitral valve insufficiency. Circulation 2001;104(12 Suppl 1):I8–11.
- Gillinov AM, Cosgrove DM, Lytle BW, Taylor PC, Stewart RW, McCarthy PM, et al. Reoperation for failure of mitral valve repair. J Thorac Cardiovasc Surg 1997;113:467–75.[Abstract/Free Full Text]
- Flameng W, Herijgers P, Bogaerts K. Recurrence of mitral valve regurgitation after mitral valve repair in degenerative valve disease. Circulation 2003;107:1609–13.[Abstract/Free Full Text]
- Carpentier AF, Lessana A, Relland JY, Belli E, Mihaileanu S, Berrebi AJ, et al. The ‘physio ring’: an advanced concept in mitral valve annuloplasty. Ann Thorac Surg 1995;60:1177–86.[Abstract/Free Full Text]
- Raffoul R, Uva MS, Rescigno G, Belli E, Scorsin M, Pouillart F, et al. Clinical evaluation of the Physio annuloplasty ring. Chest 1998;113:1296–301.[Abstract/Free Full Text]
- Sousa Uva M, Raffoul R, Belli E, Palsky E, Pouillart F, Rescigno G, et al. Initial results of mitral valvuloplasty using Physio-Carpentier-Edwards ring. Arch Mal Coeur Vaiss 1997;90:789–95.[Medline]
- Kurosawa H, Nakano M, Kawase M, Kasegawa H, Nakano K, Eishi K. Mitral valve repair by Carpentier-Edwards physio annuloplasty ring. Jpn J Thorac Cardiovasc Surg 1999;47:355–60.[Medline]
- Glasson JR, Green GR, Nistal JF, Dagum P, Komeda M, Daughters GT, et al. Mitral annular size and shape in sheep with annuloplasty rings. J Thorac Cardiovasc Surg 1999;117:302–9.[Abstract/Free Full Text]
- David TE, Komeda M, Pollick C, Burns RJ. Mitral valve annuloplasty: the effect of the type on left ventricular function. Ann Thorac Surg 1989;47:524–8.[Abstract]
- Dagum P, Timek T, Green GR, Daughters GT, Liang D, Ingels NB Jr, et al. Three-dimensional geometric comparison of partial and complete flexible mitral annuloplasty rings. J Thorac Cardiovasc Surg 2001;122:665–73.[Abstract/Free Full Text]
- Sharony R, Saunders PC, Nayar A, McAleer E, Galloway AC, Delianides J, et al. Semirigid partial annuloplasty band allows dynamic mitral annular motion and minimizes valvular gradients: an echocardiographic study. Ann Thorac Surg 2004;77:518–22.[Abstract/Free Full Text]
- Mohty D, Orszulak TA, Schaff HV, Avierinos JF, Tajik JA, Enriquez-Sarano M. Very long-term survival and durability of mitral valve repair for mitral valve prolapse. Circulation 2001;104(12 Suppl 1):I1–7.
- Chauvaud S, Fuzellier JF, Berrebi A, Deloche A, Fabiani JN, Carpentier A. Long-term (29 years) results of reconstructive surgery in rheumatic mitral valve insufficiency. Circulation 2001;104(12 Suppl 1):I12–5.
- David TE, Armstrong S, Sun Z, Daniel L. Late results of mitral valve repair for mitral regurgitation due to degenerative disease. Ann Thorac Surg 1993;56:7–12.[Abstract]
- Skoularigis J, Sinovich V, Joubert G, Sareli P. Evaluation of the long-term results of mitral valve repair in 254 young patients with rheumatic mitral regurgitation. Circulation 1994;90(5 Pt 2):II167–74.
TOP
ABSTRACT
INTRODUCTION
