Knowledge regarding gender-specific results of percutaneous edge-to-edge mitral valve repair is scarce. The aim of this study was to investigate gender differences in outcomes in a cohort of patients treated with MitraClip implantation. A multicenter registry of 173 patients treated with MitraClip prostheses from 2009 to 2012 at 3 experienced centers was performed. One hundred nine patients (63%) were men. Men were younger (mean age 73 ± 10 vs 79 ± 9 years, p = 0.001) and had a higher prevalence of previous coronary bypass graft surgery (34% vs 13%, p = 0.002), previous myocardial infarction (46% vs 20%, p = 0.001), and diabetes mellitus (26% vs 11%, p = 0.020). There were no differences regarding New York Heart Association (NYHA) functional class before the intervention (NYHA class III or IV in 95% of men vs 97% of women, p = 0.472) or the cause of mitral regurgitation (MR) (functional in 58% of men vs 48% of women, p = 0.233). Men exhibited significantly larger ventricles (mean indexed left ventricular end-systolic diameter 2.4 ± 0.8 vs 2.0 ± 1.6 cm/m 2 , p = 0.002, and mean indexed left ventricular end-diastolic volume 92.7 ± 46.1 vs 59.9 ± 24.6 ml/m 2 , p <0.001). At 1 month, there were no differences between groups in the reduction of MR or NYHA functional class (MR grade ≤2+ in 98.2% of men vs 96.8% of women, p = 0.586, and NYHA class ≤II in 78.3% of men vs 77% of women, p = 0.851). At 6 months, results were maintained (MR grade ≤2+ in 89.5% of men vs 96.8% of women, p = 0.414, and NYHA class ≤II in 73.1% of men vs 74.2% of women, p = 0.912). After a mean follow–up period of 16.1 ± 11.1 months, no difference was found between groups in the incidence of death or admission for heart failure (log-rank p = 0.798). In conclusion, MitraClip implantation seems to be an equally safe and effective treatment of MR in men and women.
Previous reports from surgical series have shown that there are substantial gender-specific differences with regard to mitral valve (MV) pathology, operative strategy, and long-term outcomes after surgical correction of mitral regurgitation (MR). Nonetheless, there is little knowledge regarding gender-specific differences in the results of edge-to-edge MV repair with the MitraClip device (Abbott Vascular, Menlo Park, California). Likewise, there are no current data with regard to the effect of body surface area (BSA) in postimplantation parameters such as mean gradient, percentage of MR reduction, and functional class improvement. Because BSA is usually significantly different between male and female patients and is strongly correlated with MV area, this fact may account for some of the differences between these subgroups. Thus, we sought to investigate gender differences in baseline characteristics and clinical and echocardiographic outcomes in a cohort of patients treated with MitraClip implantation.
Methods
From August 2009 to November 2012, 173 patients (mean age 75.5 ± 10 years, 63% men) were treated with the MitraClip device at Royal Brompton Hospital (London, United Kingdom), Rigshospitalet (Copenhagen, Denmark), and Karolinska University Hospital (Stockholm, Sweden). All patients with degenerative and functional MR were included in a retrospective analysis according to predefined inclusion and exclusion criteria.
Before intervention, all patients underwent clinical assessment and transthoracic or transesophageal echocardiography to assess New York Heart Association (NYHA) functional class, MR severity, and MV morphology. The immediate postprocedural result was assessed with transesophageal echocardiography. Transthoracic echocardiography was repeated at discharge, as was the assessment of NYHA functional class. During follow-up, death of any cause and hospitalization for heart failure were obtained from medical records if available.
The severity of MR at baseline and during follow-up was graded according to current recommendations and was assessed according to the clinical routine in respective center, using a comprehensive analysis of quantitative and qualitative echocardiographic parameters. Procedural success was defined as a reduction of the degree of MR to grade ≤2+.
The MitraClip device is an 8-mm-wide cobalt-chromium implant with 2 arms that are opened and closed using the delivery-system handle. The MitraClip procedure has been described elsewhere. Briefly, with the patient under general anesthesia and using fluoroscopic and transesophageal 2- and 3-dimensional echocardiographic guidance, the MitraClip device was advanced through the transseptal route across the mitral annulus into the left ventricle. With the 2 arms of the clip extended, the device was retracted to capture, and subsequently closed to coapt, the mitral leaflets, thereby emulating the surgical double-orifice technique.
Anticoagulation management was based on an individualized protocol. Patients receiving warfarin before clip placement continued on an identical warfarin regimen after the intervention; in the remainder of patients, acetylsalicylic acid (75 to 150 mg/day) was prescribed for 3 months and clopidogrel (75 mg/day) for 4 weeks. Clinical and echocardiographic follow-up was performed at discharge and at 1 and 6 months after the procedure.
Results are presented as mean ± SD for continuous normally distributed variables, as median (interquartile range) for continuous data not normally distributed, and as percentages for categorical data. Analysis of normality was performed with the Kolmogorov-Smirnov and Shapiro-Wilk tests. Categorical data and proportions were compared using chi-square tests or Fisher’s exact tests as required. Comparisons of continuous variables were analyzed using unpaired Student’s t test and the Mann-Whitney U test as appropriate. Survival analysis and survival curves were obtained using the Kaplan-Meier method. A p value <0.05 was considered to indicate statistical significance. All analyses were performed with SPSS version 20.0 for Windows (SPSS, Inc., Chicago, Illinois).
Results
Among the 173 consecutive patients who received MitraClip implantation from August 2009 to November 2012 at our centers, 109 patients (63%) were male. Baseline clinical characteristics in the 2 groups are listed in Table 1 . Male patients were younger and had a higher prevalence of previous revascularization, previous myocardial infarction, and diabetes mellitus. Men exhibited as well higher values of serum creatinine before the procedure. In contrast, women had a greater prevalence of chronic obstructive pulmonary disease. However, logistic European System for Cardiac Operative Risk Evaluation score did not differ between the groups.
| Variable | Overall (n=173) | Male (n=109) | Female (n=64) | p-value |
|---|---|---|---|---|
| Age (years) | 75.5±10.0 | 73.5±10.2 | 78.9±8.8 | 0.001 |
| BSA (m 2 ) | 1.9±0.2 | 2.0±0.2 | 1.8±0.2 | <0.001 |
| Diabetes mellitus | 35 (20%) | 28 (26%) | 7 (11%) | 0.020 |
| Hypertension | 107 (62%) | 66 (61%) | 41 (64%) | 0.646 |
| COPD | 32 (19%) | 15 (14%) | 17 (27%) | 0.036 |
| Stroke | 15 (9%) | 12 (11%) | 3 (5%) | 0.154 |
| Previous MI | 63 (36%) | 50 (46%) | 13 (20%) | 0.001 |
| Previous PCI | 41 (24%) | 31 (28%) | 10 (16%) | 0.056 |
| Previous CABG | 45 (26%) | 37 (34%) | 8 (13%) | 0.002 |
| Previous AVR | 14 (8%) | 11 (10%) | 3 (5%) | 0.208 |
| Previous AF | 78 (45%) | 50 (46%) | 28 (44%) | 0.418 |
| NYHA functional class | 0.356 | |||
| II | 8 (4%) | 6 (6%) | 2 (3%) | |
| III | 138 (80%) | 89 (82%) | 49 (77%) | |
| IV | 27 (16%) | 14 (13%) | 13 (20%) | |
| Functional MR | 94 (54%) | 63 (58%) | 31 (48%) | 0.233 |
| Logistic EuroSCORE (%) | 18.7±14.9 | 18.3±14.3 | 19.4±16.1 | 0.645 |
| Baseline creatinine (μmol/L) | 119.4±62.5 | 126.6±62.6 | 106.9±60.7 | 0.046 |
| Baseline haemoglobin (g/dL) | 12.1±1.8 | 12.1±1.8 | 11.9±1.7 | 0.388 |
Echocardiographic parameters are listed in Table 2 . There were significant differences between baseline characteristics of the groups with larger ventricles and a trend toward lower ejection fractions in the male group. Likewise, male patients had significantly larger annular areas (n = 108, median 6.7 cm 2 /m 2 [interquartile range 5.5 to 8.0] vs 5.9 cm 2 /m 2 [interquartile range 4.8 to 7.0], p = 0.012).
| Variable | Pre-Clip | Post-Clip (1month) | ||||||
|---|---|---|---|---|---|---|---|---|
| Overall (n=173) | Male(n=109) | Female (n=64) | p ∗ | Overall (n=173) | Male (n=109) | Female (n=64) | p † | |
| Left ventricular end-diastolic diameter (cm/m 2 ) | 3.1±0.5 | 3.2±0.5 | 3.0±0.5 | 0.108 | 3.0±0.5 | 3.1±0.6 | 2.9±0.6 | 0.084 |
| Left ventricular end-systolic diameter (cm/m 2 ) | 2.2±0.7 | 2.4±0.8 | 2.0±1.6 | 0.002 | 2.3±0.7 | 2.4±0.7 | 2.1±0.7 | 0.019 |
| Left ventricular end-diastolic volume (ml/m 2 ) | 80.8±42.6 | 92.7±46.1 | 59.9±24.6 | <0.001 | 75.7±38.0 | 90.3±48.7 | 53.9±24.8 | <0.001 |
| Left ventricular end-systolic volume (ml/m 2 ) | 48.2±24.2 | 59.3±27.0 | 30.4±22.9 | <0.001 | 47.5±27.3 | 59.3±25.3 | 30.6±16.4 | 0.001 |
| Left ventricular ejection fraction (%) | 48.2±18.2 | 42.8±18.3 | 48.1±17.6 | 0.064 | 43.1±17.1 | 41.3±17.0 | 45.8±17.0 | 0.121 |
| MR quantification | ||||||||
| Effective regurgitant orifice area (cm 2 ) | 0.46±0.3 | 0.48±0.3 | 0.42±0.3 | 0.455 | – | – | – | – |
| Vena contracta (mm) | 7.2±2.1 | 7.3±2.2 | 7.0±2.0 | 0.658 | – | – | – | – |
| Regurgitant volume (ml) | 58.7±21.7 | 59.2±31.0 | 57.7±33.0 | 0.822 | – | – | – | – |
| Baseline mean mitral gradient (mmHg) | 2.0±1.0 | 2.1±1.1 | 2.0±1.0 | 0.535 | 3.2±2.2 | 3.1±2.2 | 3.4±2.2 | 0.171 |
| Systolic pulmonary pressure (mmHg) | 50.1±14.6 | 50.9±13.5 | 48.4±16.0 | 0.354 | 43.3±11.4 | 43.1±11.1 | 43.4±12.1 | 0.893 |
Procedural success was obtained in 169 patients (98%), with no significant differences between male patients (n = 107 [98%]) and female patients (n = 62 [97%]) (p = 0.586). With regard to the number of clips implanted, we found no significant difference between groups, although numerically more male patients received >1 clip (40% vs 30%, p = 0.159). Periprocedural complications are listed in Table 3 .
| Variable | Overall (n=173) | Male (n=109) | Female (n=64) | p |
|---|---|---|---|---|
| Clip embolization | 0 | 0 | 0 | – |
| Partial clip detachment | 5 (3%) | 2 (2%) | 3 (5%) | 0.360 |
| Chordal rupture | 1 (1%) | 1 (1%) | 0 | 1.000 |
| Cardiac tamponade | 2 (1%) | 2 (2%) | 0 | 0.531 |
| Stroke | 1 (1%) | 0 | 1 (2%) | 0.370 |
| Transient AV block | 1 (1%) | 1 (1%) | 0 | 1.000 |
| Pneumonia | 1 (1%) | 0 | 1 (2%) | 0.370 |
| Mitral valve surgery | 2 (1%) | 2 (2%) | 0 | 0.531 |
| Death | 4 (2%) | 2 (2%) | 2 (3%) | 0.627 |
| All complications | 17 (10%) | 10 (9%) | 7 (11%) | 0.793 |
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