The feasibility of transcatheter mitral valve therapy (edge-to-edge or valve-in-ring technique) in patients with significant mitral regurgitation (MR) recurrence after surgical restrictive mitral valve annuloplasty remains unknown. The aim of the present study was to investigate the eligibility for transcatheter mitral valve therapy of high-surgical-risk patients with significant MR recurrence after initial successful restrictive mitral valve annuloplasty. A total of 47 patients (age 67 ± 10 years, 47% men) with significant MR recurrence (effective regurgitant orifice area ≥20 mm 2 , regurgitant volume ≥30 ml/beat, or vena contracta ≥3 mm) after restrictive mitral valve annuloplasty were identified. The long-term outcome of patients dichotomized according to the surgical risk was evaluated. The echocardiographic parameters of mitral valve geometry and hemodynamics at the moment of diagnosis of MR recurrence were assessed to evaluate the eligibility for transcatheter valve therapy. During a median follow-up of 3 years, 23 patients (48.9%) died. The patients with a high-surgical risk (logistic European System for Cardiac Operative Risk Evaluation score ≥20%) had significantly worse long-term survival than those with a low-surgical risk (logistic European System for Cardiac Operative Risk Evaluation score <20%; 50% and 88%, respectively; p = 0.002). All high-surgical-risk patients showed geometric mitral valve features that would allow transcatheter mitral valve therapy (mitral annular area 7 ± 2.0 cm 2 , coaptation length 6 ± 1.6 mm, anterior and posterior mitral leaflet length 24 ± 2.8 mm and 15 ± 3.1 mm, respectively). In conclusion, patients with significant MR recurrence after initial successful restrictive mitral valve annuloplasty and a high risk of redo mitral valve surgery had lower long-term survival rates than patients who could undergo repeat surgery.
Functional mitral regurgitation (MR) is an important prognostic determinant of patients with heart failure. Optimal medical management can improve heart failure symptoms and halt progression of left ventricular remodeling but does not affect survival. Surgical mitral valve repair is an effective therapy that provides significant improvements in symptoms and left ventricular function. However, despite significant advances in surgical techniques, the operative risks of patients with heart failure and significant functional MR are not negligible, and MR recurrence rates can reach almost 20% at long-term follow-up. Reoperation of these high-risk patients has been associated with high mortality. New minimally invasive or transcatheter-based mitral valve repair and replacement techniques might be feasible therapeutic options for patients with recurrent MR after surgical mitral valve repair. The percentage of patients who might be candidates for percutaneous mitral valve repair or replacement techniques after restrictive mitral annuloplasty remains unknown. Accordingly, the present study aimed at evaluating the long-term survival of patients with significant MR recurrence after successful surgical restrictive mitral valve annuloplasty and to investigate whether patients with a high risk of surgical reoperation would be suitable for transcatheter valve therapy.
Methods
A total of 47 patients with significant recurrence of MR after initially successful surgical mitral valve repair were identified from an ongoing clinical registry. Successful surgical restrictive mitral valve annuloplasty was defined as no residual MR and coaptation of the mitral leaflets of ≥8 mm at the level of the central scallops on the transesophageal echocardiogram performed in the operating theater. Significant MR recurrence was defined as an effective regurgitant orifice area of ≥20 mm 2 , regurgitant volume of ≥30 ml/beat, or vena contracta ≥3 mm. Patients with significant MR recurrence due to dehiscence of the mitral ring were excluded. The clinical and echocardiographic characteristics were collected at the diagnosis of significant MR recurrence. The patients were divided into 2 groups according to the operative risk, which was calculated using the logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE): patients with a high operative risk were defined by a logistic EuroSCORE of ≥20% and those with a low operative risk were defined by a logistic EuroSCORE of <20%. The survival rates of each group were retrospectively evaluated with the follow-up period starting with the diagnosis of MR recurrence. In addition, the eligibility for transcatheter valve therapy (edge-to-edge repair or valve-in-ring procedure) was evaluated according to various hemodynamic and geometric parameters of the mitral valve measured on the transthoracic echocardiogram. The clinical and echocardiographic data were recorded at the departmental Cardiology Information System (EPD-Vision, Leiden University Medical Center, Leiden, The Netherlands) and the echocardiographic database and were retrospectively analyzed. The follow-up data were recorded from a review of the medical records and retrieval of the survival status through municipal civil registries. The end point was all-cause mortality.
Transthoracic echocardiography (System Five or Vivid 7, GE Norway, Horten, Norway) was performed in all patients before hospital discharge to confirm the absence of MR and repeated during the follow-up period at the discretion of the treating physician. The left ventricular dimensions, geometry, and function were assessed according to current recommendations. The mitral valve geometry and hemodynamics were evaluated from the echocardiogram that showed significant MR recurrence. That echocardiogram was considered the baseline echocardiogram for the present evaluation. MR severity was quantitatively determined by the proximal isovelocity surface area method and by measuring the vena contracta according to the current guidelines. The geometry of the mitral valve was evaluated in mid-systole, as previously described. The tenting area, coaptation depth, and coaptation length were measured in the parasternal long-axis view. The coaptation length was measured as the length of apposition of the anterior and posterior mitral leaflets at the A2-P2 level ( Figure 1 ). The tenting area was measured as the area enclosed between the annular line and the mitral leaflets. The coaptation depth was defined as the distance between the coaptation point and the annular line ( Figure 1 ). The mobile length of the anterior and posterior mitral leaflets was measured in mid-diastole ( Figure 1 ). The mitral annular area was calculated according to the ellipsoid assumption, measuring the annular diameters at the apical 2- and 4-chamber views.
Of several percutaneous mitral valve repair techniques, the edge-to-edge procedure using the MitraClip device (Abbott Vascular, Abbott Park, Illinois) has the largest experience. The valve-in-ring implantation has been successfully performed for failed surgical mitral ring annuloplasty using the Edwards SAPIEN valve (Edwards Lifesciences, Irvine, California). According to currently used clinical criteria in the assessment of the eligibility of a patient for transcatheter valve therapy, patients with recurrence of significant MR were considered amenable for transcatheter mitral valve therapy if they were at high surgical risk (logistic EuroSCORE ≥20%) for redo mitral valve repair and did not need any other cardiac surgery. Furthermore, they should not have a history of rheumatic valve disease or endocarditis and should have no evidence of acute myocardial infarction in the 12 weeks before the intended treatment. Moreover, transesophageal echocardiography and transseptal catheterization had to be feasible. For the transapical valve-in-ring procedure, a complete annuloplasty ring should have been implanted during the mitral valve repair and the left ventricle had to be transapically accessible (i.e., no previous cardiac support device). For the transcatheter edge-to-edge procedure, the following echocardiographic parameters are of importance: mitral valve orifice area ≥2.0 cm 2 , coaptation length of the mitral leaflets >2.0 mm, and sufficient mitral leaflet tissue for mechanical coaptation, defined as a mitral leaflet length of ≥10 mm.
Continuous variables are presented as the mean ± SD and categorical variables as percentages. Comparisons of the baseline characteristics between the high-risk and low-risk surgical patients were performed using the Student t test for continuous variables and Pearson’s chi-square test for categorical variables. Unadjusted survival rates after significant MR recurrence were calculated using the Kaplan-Meier method, and log-rank tests were applied to evaluate the differences between the survival rates of patients at high and low operative risk. Patients who were lost to follow-up were considered at risk until the date of last contact, at which point they were censored. All statistical tests were 2-tailed, and p <0.05 was considered statistically significant. Statistical analysis was performed using the Statistical Package for Social Sciences, version 17.0.2, for Windows (SPSS, Chicago, Illinois).
Results
The baseline demographic and clinical characteristics of the patients are listed in Table 1 . The surgical patient history is listed in Table 2 . Of the 47 patients, 31 were considered to have a high risk of redo mitral valve repair or replacement (logistic EuroSCORE ≥20%), and 16 to have low operative risk. The baseline characteristics were similar in both groups. However, the high-surgical-risk patients were mostly women, were older, and were more likely to have atrial fibrillation than the low-surgical-risk patients. During a median follow-up of 3.1 years (interquartile range 1.4 to 6.4), 23 patients (48.9%) died. Patients with a high risk of reoperation had significantly worse long-term survival than those with a low risk. The cumulative survival curves are presented in Figure 2 . After 3 years of follow-up, the cumulative survival rate of the low-surgical-risk patients was 88% compared with 50% in the group of patients at high risk of reoperation at the diagnosis of MR recurrence (p = 0.002).
| Variable | All Patients (n = 47) | Low-Risk Patients (n = 16) | High-Risk Patients (n = 31) | p Value |
|---|---|---|---|---|
| Age (yrs) | 68 ± 11 | 60 ± 11 | 72 ± 8 | 0.001 |
| Male gender (%) | 47 | 69 | 36 | <0.05 |
| Body surface area (m 2 ) | 2 ± 0.2 | 2 ± 0.2 | 2 ± 0.2 | 0.2 |
| Ischemic cardiomyopathy (%) | 33 | 47 | 26 | 0.2 |
| Atrial fibrillation (%) | 26 | 6 | 36 | <0.05 |
| Hypertension (%) | 50 | 46 | 52 | 0.7 |
| Hyperlipidemia (%) | 53 | 46 | 56 | 0.6 |
| Positive family history for cardiovascular disease (%) | 45 | 54 | 40 | 0.4 |
| Diabetes mellitus (%) | 20 | 8 | 26 | 0.2 |
| Smoking (%) | 11 | 14 | 9 | 0.6 |
| Exsmoker (%) | 41 | 43 | 39 | 0.8 |
| Chronic obstructive pulmonary disease (%) | 17 | 14 | 19 | 0.7 |
| Previous stroke (%) | 13 | 21 | 8 | 0.2 |
| Peripheral vascular disease (%) | 13 | 0 | 20 | 0.07 |
| New York Heart Association functional class (%) | 0.6 | |||
| III | 42 | 36 | 46 | |
| IV | 21 | 18 | 23 | |
| Creatinine (μmol/L) | 149 ± 107 | 156 ± 152 | 145 ± 76 | 0.8 |
| Glomerular filtration rate (ml/min) | 57 ± 31 | 68 ± 42 | 50 ± 21 | 0.2 |
| Cardiac resynchronization therapy (%) | 43 | 42 | 44 | 0.9 |
| Medications (%) | ||||
| β Blocker | 62 | 75 | 56 | 0.3 |
| Angiotensin-converting enzyme or angiotensin receptor blocker | 51 | 42 | 56 | 0.4 |
| Diuretics | 87 | 75 | 92 | 0.2 |
| Anticoagulants | 51 | 58 | 48 | 0.6 |
| Aspirin | 95 | 92 | 96 | 0.6 |
| Statins | 62 | 67 | 60 | 0.7 |
| Digoxin | 35 | 42 | 32 | 0.6 |
| Variable | All Patients (n = 47) | Low-Risk Patients (n = 16) | High-Risk Patients (n = 31) | p Value |
|---|---|---|---|---|
| Previous CABG (%) | 51 | 50 | 52 | 0.9 |
| Previous CorCap cardiac support device (%) | 17 | 13 | 19 | 0.6 |
| Previous tricuspid valvuloplasty (%) | 36 | 27 | 40 | 0.4 |
| Complete, semirigid annuloplasty ring (%) | 100 | 100 | 100 | 1.0 |
| Mitral valve annuloplasty ring size (mm) | 27 ± 2.2 | 28 ± 2.4 | 26 ± 2.0 | 0.07 |
The baseline echocardiographic characteristics of the patients are listed in Table 3 . The geometric and hemodynamic characteristics of the mitral valve are listed in Table 4 . According to their mitral valve characteristics and the clinical and technical criteria, all high-surgical-risk patients with MR recurrence would be amenable for transcatheter valve therapy with the MitraClip device (Abbott Vascular). None of the patients had rheumatic valve morphology or active endocarditis. Previous implantation of a cardiac support device (e.g., CorCap cardiac support device, Acorn Cardiovascular, St. Paul, Minnesota) might, however, have contraindicated a transapical approach for the valve-in-ring procedure in 6 patients (19%). However, an antegrade transseptal approach would be still feasible in these patients.
