| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2007;83:1303-1309
© 2007 The Society of Thoracic Surgeons
a Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, Stockholm, Sweden
b Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
c Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
Accepted for publication November 21, 2006.
* Address correspondence to Dr Sartipy, Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, SE-17176 Stockholm, Sweden (Email: ulrik.sartipy{at}karolinska.se).
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
Methods: From March 1997 to July 2002, 31 patients with left ventricular aneurysm or ischemic dilated cardiomyopathy and functional ischemic mitral regurgitation grade II (n = 18), III (n = 10), and IV (n = 3) underwent SVR and edge-to-edge repair without annuloplasty with concomitant coronary artery bypass grafting. Long-term valve competence was assessed by echocardiography. Early and late survival and hospital readmission for heart failure were analyzed.
Results: Early mortality was 5 (16%) of 31 patients. At 1, 3, and 5 years, actuarial survival was 77%, 55%, and 48%. The cumulative follow-up was 117 patient-years (4.5 years mean follow-up). Late echocardiograms performed at a mean of 3.1 years postoperatively showed patients had mitral regurgitation at grade 0 (n = 4), I (n = 10), II (n = 9), and III (n = 1). Two patients underwent reoperation owing to grade III–IV recurrent mitral regurgitation. Freedom from hospital readmission or cardiac death was 56% at 1 year and 48% at 3 years.
Conclusions: Combined mitral valve repair and SVR carries high operative risk and long-term prognosis is worse than after SVR alone. The edge-to-edge repair without annuloplasty for functional ischemic mitral regurgitation seems to be fairly durable in conjunction with SVR. To improve results a transventricular annuloplasty may be added.
|
Introduction |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
Edge-to-edge repair [8, 9] is an attractive option for correction of functional ischemic MR and can readily be performed by a transventricular approach during SVR. However, concerns have been raised about the durability of the edge-to-edge repair without annuloplasty, particularly in patients with ischemic cardiomyopathy [10, 11]. In a recent study, we found a strong association between increasing grade of preoperative MR and both long-term mortality and readmission for heart failure [12].
The objective of this study was to analyze the durability of edge-to-edge mitral valve repair performed without annuloplasty in combination with SVR in patients with functional ischemic MR and LV aneurysm or ischemic dilated cardiomyopathy. The primary variable of interest was the grade of MR at late follow-up. Secondary outcome measures were early and late all-cause mortality and readmission for heart failure.
|
Patients and Methods |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
Patient Selection
From May 1994 to October 2005, 138 patients underwent SVR by the Dor procedure for a postinfarction dyskinetic LV aneurysm or a large nonaneurysmal akinetic left ventricle at our institution. Patients were selected for SVR if they demonstrated an enlarged dyskinetic or akinetic left ventricle accompanied by LV dysfunction after myocardial infarction and had symptoms of angina, heart failure, or both. Assessment of LV volume and geometry was made by ventriculography and, late in this series, also by magnetic resonance imaging.
A mitral valve procedure was performed in 37 patients. All patients had ischemic MR, defined as MR in patients with a prior myocardial infarction but with normal leaflets. One patient received a mechanical prosthesis. Mitral valve repair was accomplished in 2 patients with a rigid ring annuloplasty, which was combined with an Alfieri edge-to-edge plasty [9] in one patient. The edge-to-edge technique was associated with a posterior annuloplasty without a ring in 3 patients, as described by Menicanti and colleagues [5]. The study population consisted of 31 patients with functional ischemic MR who underwent the mitral valve repair that was done solely by the edge-to-edge technique, without annuloplasty, in combination with SVR by the Dor procedure.
Echocardiography
The mitral valve function was assessed preoperatively by transthoracic echocardiography (TTE). Intraoperative transesophageal echocardiography (TEE) was used in all patients to confirm preoperative findings and to assess valve morphology and postoperative result after weaning from extracorporeal circulation. TTE was performed before hospital discharge and at late follow-up. The degree of MR was assessed in a semiquantitative way, using the following scale: 0, absent; I, trivial; II, mild; III, moderate; IV, severe.
Patient Characteristics
There were 23 men and 8 women (n = 31), their mean age was 66 ± 9.6 years (range, 48 to 79 years), and 26 (84%) were in New York Heart Association (NYHA) functional class III or IV. The mean preoperative LV ejection fraction was 0.21 ± 0.08 (range, 0.05 to 0.40). MR grade II was present in 18 patients (58%), and 13 patients (42%) had MR grade III–IV. In 25 patients, the mean ± standard deviation (SD) LV end-diastolic diameter was 65 ± 9 mm (range, 47 to 79 mm). Baseline characteristics and indications for surgery are presented in Table 1.
|
Data Collection and Follow-Up
A national registration number is allocated to every Swedish citizen. In August 2006, survival was determined in the cohort by using the continuously updated population register, the Total Register of the Swedish Population, Statistics Sweden. By this procedure all patients could be assigned a date of death or identified as being alive on August 21, 2006. Data collection consisted of review of patients’ records, our institutional database, and data from the national Cause of Death Register, Centre for Epidemiology at the National Board of Health and Welfare, Sweden.
Time to readmission was defined as the time from the operation to the combined end-point of first hospital readmission owing to heart failure or cardiac death in the 26 operative survivors. The date for the first hospital readmission owing to heart failure was established by use of the Swedish In-patient Register, Centre for Epidemiology at the National Board of Health and Welfare, Sweden, and confirmed by hospital records. The validity of the diagnosis of heart failure in the Swedish In-patient Register has recently been examined and found to be very high (96%) in patients treated at an internal medicine or cardiology department or when heart failure was the primary diagnosis [15].
Postoperative MR was evaluated by TTE in the four-chamber view and semi-quantitatively assessed applying a categoric grading from 0 (absent) to IV (severe).
Outcome Measures
The primary variable of interest was the grade of MR at the most recent TTE at follow-up. Secondary outcome measures were early and late all-cause mortality and the combination of first readmission for heart failure or cardiac death, which was defined as death owing to cardiac failure, ischemic events, or sudden death.
Statistical Analysis
Continuous variables are reported as mean ± standard deviation. Cumulative survival rates are presented as Kaplan-Meier estimates. Differences between survival curves were analyzed by using the log-rank test. Relationship between risk factors and early mortality were analyzed by using contingency tables and the Fisher exact test for categoric variables and Mann-Whitney U test for continuous variables. Statistical analyses were performed using SPSS 14.0 (SPSS Inc, Chicago, IL).
|
Results |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
|
|
Postbypass TEE valve assessment showed grade 0 MR in 17 patients and grade I MR in 7. Two patients with preoperative grade II MR had a residual grade II MR immediately after surgery. Detailed TEE postbypass data were not available in 5 patients, including the intraoperative fatality. No patient left the operating theatre with grade III–IV MR.
Predischarge TTE valve assessment in operative survivors showed grade 0 MR in 6 patients and grade I MR in 13. Five patients were discharged with grade II MR, of whom 1 had grade IV MR, 2 had grade III MR, and 2 had grade II MR before surgery. Detailed TTE predischarge data were not available in 2 patients. Both had grade II MR at late follow-up. No patient was discharged with grade III–IV MR. The MR grade at different time-points is shown in Figure 1.
|
|
Recurrence of mitral regurgitation
Two patients underwent reoperation at 3 and 13 months after the primary operation, respectively, owing to recurrent grade III–IV MR. In one patient, the Alfieri stitch had torn, resulting in a large MR; in the other, the edge-to-edge plasty was intact and the mechanism for the MR was progressive annular dilation. Both underwent mitral valve replacement. The patient with the annular dilatation had a preoperative LV end-diastolic diameter of 74 mm and a residual MR grade II at discharge. He underwent successful heart transplantation 1 year after mitral valve replacement.
Mitral valve status at late follow-up
The MR grade at late follow-up is shown in Figure 1. Valve assessment by TTE in operative survivors at late follow-up showed grade 0 MR in 4 patients, grade I MR in 10, and grade II MR in 9. Only 1 patient had MR grade III at follow-up 2 years after surgery. Five years later, at the end of this study, this patient was alive at age 78. She has refused further TTE examinations, leaving us unaware of her present mitral valve status.
Freedom from recurrence of MR is also shown in Figure 3, where time to event is the time in years between surgery and last available TTE. Freedom from grade III–IV MR was 95% at 1 year, 90% at 2 years, and 83% at 5 years, with 9 patients remaining at risk. Freedom from a combination of death, valve reoperation, and recurrence of MR grade III–IV in the 13 patients with preoperative MR grade III–IV was 59% at 1 year and 25% at 3 years.
|
|
Comment |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
Ischemic Mitral Regurgitation
Functional ischemic MR is generally defined as a condition in which the mitral valve itself is normal but ischemic heart disease has led to changes in LV volume, shape, and function, causing MR. Thus, ischemic MR is considered to be a ventricular disease, not a valve disease. Ischemic MR results from LV remodeling (ventricular enlargement and increased sphericity), with annular dilatation and papillary muscle displacement with associated leaflet tethering and lack of coaptation. Ischemic MR results in LV volume overload, resulting in further LV remodeling with progressive MR, and thus a vicious circle is created.
When Should the Valve Be Repaired?
At present, there is no consensus for when and how to correct mild-to-moderate MR in conjunction with SVR, although it is generally accepted that moderate-to-severe MR is an indication for a direct valve procedure. A 2006 study of patients undergoing isolated CABG without severe MR reported that the presence of moderate, and even mild, functional ischemic MR was associated with decreased survival [16]. Other authors have shown that CABG alone for coronary artery disease with mild-to-moderate ischemic MR leaves many patients with significant residual MR [17, 18], suggesting that lone revascularization is insufficient for treatment of ischemic MR. In a study by Di Donato and coworkers [19], MR was detected after the Dor procedure in 17 of 44 patients, and 14 did not have any preoperative MR. The patients in whom late MR developed had greater preoperative LV volumes than the patients without late MR, suggesting a lower threshold for performing a direct valve procedure in patients with the largest LV volumes. Mickleborough and colleagues [20] presented a large series of LV reconstruction by a modified linear closure technique. In 129 patients with 2+ MR or more, no valve procedure was performed, and in 74 (57%), MR improved by at least 1 grade. The authors proposed possible mechanisms for improvement, including decreased annular dilatation caused by decreased ventricular size, improved papillary muscle function owing to revascularization, and realignment of papillary muscles related to improved LV geometry.
Thus, there is evidence of poor outcome in mild or moderate ischemic MR, not resolved by CABG alone. On the other hand, some less solid data have described a beneficial effect of LV reconstruction on severity of MR [7, 20], theoretically based on improved LV and papillary muscle geometry.
In our series, we elected to repair the mitral valve during SVR in all patients with MR grade III–IV and in about half of the cases with grade II MR. Our threshold was lower in patients with very large ventricles.
How Should the Valve Be Repaired?
Favorable results after restrictive mitral annuloplasty in functional ischemic MR have been reported [21–23]. A study by Braun and colleagues [23] of 87 patients with ischemic MR and LV dysfunction who underwent restrictive mitral annuloplasty with or without revascularization found that reverse remodeling occurred in most patients; however, in patients with a preoperative LV end-diastolic diameter exceeding 65 mm or an LV end-systolic diameter exceeding 51 mm, the probability of reverse remodeling was low. Even in the absence of recurrent MR, reverse remodeling did not occur in such large left ventricles. The authors’ interpretation was that the extent of disease of the left ventricle was the limiting factor in the process of reverse remodeling, and they have changed their approach. They now apply a CorCap Cardiac Support Device (Acorn Cardiovascular, Inc, St Paul, MN) in all patients with ischemic MR and dilated cardiomyopathy with a LV end-diastolic diameter exceeding 65 mm [23].
Ventricular Approach to the Mitral Valve
Menicanti and colleagues [5] reported an innovative technique to repair moderate-to-severe MR during SVR. It consists of reducing the posterior mitral annulus and imbricating the papillary muscles, without a prosthetic ring, through the ventriculotomy during SVR. A study of 108 patients who underwent mitral repair by this method in combination with SVR found that the operative cardiac mortality was 16.6% [7]. The degree of MR went from 2.9 before surgery to 0.7 early after surgery and 1.5 late after surgery. Survival at 3 years was 62%.
A recent anatomic study analyzed mitral valve and ventricular size in ischemic and idiopathic dilated cardiomyopathy [24]. The researchers found that most of the annular dilatation occurred in the posterior mitral annulus. They also found an increase in the intertrigone distance that was proportional to the increase in the posterior annulus. Thus, dilatation of mitral ring is proportional and does not exclusively affect the posterior portion, which suggests that complete mitral annuloplasty techniques might be preferred.
The ventricular approach to the mitral valve during SVR is attractive because it simplifies the procedure and saves time. The Alfieri edge-to-edge technique [9] during SVR has been used by our group [13] and others [11].
Edge-to-Edge Repair With or Without Annuloplasty
A retrospective analysis of 81 patients with mostly degenerative etiology who underwent edge-to-edge mitral repair without annuloplasty found that 9 patients required reoperation during the follow-up period and overall freedom from reoperation at 4 years was 89% [10]. In another article from the same group, freedom from reoperation was significantly higher in patients who received an annuloplasty procedure compared with patients who did not [8]. Again, the absolute majority of the patients had degenerative cause of MR, and the authors point out that the role of the edge-to-edge plasty in ischemic MR is not clearly defined.
De Bonis and colleagues [22] reported that the association of the edge-to-edge technique with the undersized annuloplasty with a complete ring can significantly improve the durability of the repair in patients with end-stage dilated cardiomyopathy. The etiology was ischemic in 51 patients (67%), and 76% of these had concomitant CABG. The freedom from recurrence of MR grade III IV at 1.5 years was 95% in the edge-to-edge group and 77% in the isolated undersized annuloplasty group (p = 0.04).
The Cleveland Clinic group recently described their experience with the edge-to-edge technique in 224 patients in a diverse clinical setting [11]. The indication for surgery was ischemic cardiomyopathy in 143 patients (64%). LV reconstruction was performed in 48, and the mitral valve approach was transventricular in 20. Most patients (84%) had an associated annuloplasty with a flexible partial band that extended from trigone to trigone, and the most common size in ischemic MR was 26 mm; however, 16 patients had no ring annuloplasty, these were usually patients who underwent LV reconstruction. The authors reported good early term outcome but a disappointing 24% late recurrence rate of moderate-to-severe mitral regurgitation at 2 years. Patients with ischemic cardiomyopathy did worse than patients with dilated cardiomyopathy. Of interest was that among patients with ischemic cardiomyopathy, no difference was found in the recurrence of mitral regurgitation between patients who underwent LV reconstruction and those who did not.
The recurrence rate in our study was at 2 years was 10%; however, these results are not easily comparable partly because of differences in the patient population. In The Cleveland Clinic study [11], 78% of the patients had grade III–IV MR preoperatively; in our study, only 42% of the patients had a preoperative grade III–IV MR.
Study Limitations
This is a retrospective observational study without any control group, which prohibits firm conclusions to be drawn about the preferred approach to mitral valve repair and SVR. Long-term assessment of the mitral valve was not protocol-driven, and our analysis relies on available TTE performed at the discretion of the patient’s cardiologist. This may introduce bias; however, patients presenting with clinical symptoms are more likely to undergo further evaluation, including TTE. This probably leads to patients being identified whose results are less than optimal. Another limitation is the lack of detailed control of concurrent medication. An important limitation of this study is the lack of information on preoperative and postoperative LV volume data in most patients; factors that we know have an important affect on mitral repair durability, prognosis, and survival.
Conclusions
Ischemic MR in ischemic dilated cardiomyopathy worsens the prognosis considerably and amplifies the risk for the patient undergoing surgery. Mitral valve repair during SVR adds to the complexity of the procedure and a simple valve repair technique is therefore desirable. We report in this study our experience with the edge-to-edge repair without supportive annuloplasty during SVR with reasonably good long-term results. However, our own results and reports by other institutions [8, 11] of suboptimal long-term durability convinced us to change our policy, and since 2003, we have added annuloplasty to mitral valve repair during SVR, usually as a posterior plication suture [5].
|
Acknowledgments |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
|
References |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  L. R Sajja, G. Mannam, B. R S Dandu, S. Pathuri, S. Sompalli, and A. Anjaneyulu Outcomes of Mitral Valve Repair for Chronic Ischemic Mitral Regurgitation Asian Cardiovasc Thorac Ann, January 1, 2009; 17(1): 29 - 34. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Lindblom, A. Albage, and U. Sartipy Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration MMCTS, December 17, 2007; 2007(1217): 2816. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Di Donato, S. Castelvecchio, J. Brankovic, C. Santambrogio, V. Montericcio, and L. Menicanti Effectiveness of surgical ventricular restoration in patients with dilated ischemic cardiomyopathy and unrepaired mild mitral regurgitation. J. Thorac. Cardiovasc. Surg., December 1, 2007; 134(6): 1548 - 1553. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
