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Eur J Cardiothorac Surg 1998;13:240-246
© 1998 Elsevier Science NL
a Division of Cardiac Surgery, IRCCS S. Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
b Cardiac Surgery Department, Civic Hospital, Brescia, Italy
Received 14 October 1997; received in revised form 2 January 1998; accepted 14 January 1998.
Corresponding author. Tel.: +39 2 26437109; fax: +39 2 26437125; e-mail: maisanf@carchisrv.hsr.it
| Abstract |
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Key Words: Mitral valve Valve repair Surgical technique
| Introduction |
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Since 1991, we developed a simple surgical procedure to correct mitral valve prolapse, the edge-to-edge (E-to-E) technique, which restores valvular competence by anchoring the free edge of the prolapsing leaflet to the corresponding free edge of the opposing leaflet. Although originally used only to correct prolapsing lesions, the technique has been effectively extended to correction of MR due to restricted leaflet motion secondary to rheumatic or ischemic disease. Herein is the report of the middle term results of this alternative technique for mitral valve repair.
| Methods |
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Etiology of the disease was degenerative in the majority of patients (82 patients, 68%), as shown in Table 1. Two patients had already been submitted to open heart surgery: one patient had had an aortic valve replacement and one patient had had mitral valve repair (Carpentier ring annuloplasty). The latter patient had a residual severe MR due to flail posterior leaflet.
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Coronary angiography and left heart catheterization was not routinely carried out in the absence of symptoms or risk factors for coronary artery disease.
Surgical technique
Minimal technical modifications of the conduction of the operation were introduced during the study period. Currently, valve repair is routinely carried out through a conventional midline sternotomy, in normothermic cardiopulmonary by-pass, using intermittent normothermic blood cardioplegia. Mitral valve is approached through the left atrium, with the incision done in the interatrial groove.
Following the identification of the prolapsing portion of a leaflet, this is resuspended suturing its free edge to the corresponding edge of the opposing leaflet, usually with a figure of eight stitch using a 50 polypropylene suture, additional mattress sutures reinforced with pericardial pledgets are usually placed in case of thin leaflets ( Fig. 1 ). When the prolapse is in the middle portion of a leaflet, the correction creates a double orifice valve, while, in case of commissural lesions, the correction simply results in a valve with a smaller orifice area (paracommissural repair).
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Excluding annuloplasty, additional procedures to restore leaflet coaptation were needed in 33 patients (Table 3), in the remaining 88 patients (73%) the E-to-E repair alone was sufficient to correct MR even when it was due to multiple or complex lesions. On the other hand an annuloplasty was associated in almost all the patients (113 patients, 93%), it was not done in case of small mitral annulus (6 patients) or in case of rheumatic disease with restricted leaflet motion (2 patients).
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Associated cardiac procedures were carried out as needed: coronary artery by-pass grafting (7 patients); aortic valve replacement (8 patients); aortic valve repair (3 patients); tricuspid valve annuloplasty (6 patients); correction of atrial septal defect (1 patient); and correction of Valsalva sinus aneurysm (1 patient).
Mean cardiopulmonary by-pass time and aortic cross clamp time were 52±11.7 min and 35±4.7 min, respectively. Excluding patients undergoing associated cardiac procedures, mean by-pass and ischemic times were 48±7.3 min and 31±2.7 min.
Echocardiography
After induction of general anesthesia, transesophageal echocardiography with an omniplane probe (HP Sonos 1000) was carried out. The diagnosis and etiology of MR was confirmed in four chambers and short axis transgastric views. Regurgitant blood flow was quantified by jet area of turbulence in left atrium with color Doppler: regurgitation was graded as absent (0); trivial (1+); mild (2+); moderate (3+); and severe (4+). Mitral valve area was measured by modified Bernoulli equation (PHT) and by planimetric method in transgastric short axis view. The measurements were done before and after CPB during hemodynamic stability. Transthoracic approach was preferred for follow-up studies (carried out in 87 patients).
Follow-up
Follow-up information was obtained from all hospital survivors from 1 August 1997 to 5 September 1997. The mean period of follow-up was 2.2±1.5 years (range from 1 month to 6.6 years), for a cumulative follow-up of 269 patient years. Data were collected either through outpatient visit, including echocardiographic examination (87 patients, 73% of hospital survivors), or by telephone contact with the patient or the referring physician.
Statistical analysis
Data were analyzed using the statistical package JMP for Macintosh (SAS Institute, Cary NC). Values are reported as mean±1 S.D. Student t-test was used for comparison between the means of continuous variables. Event-free survival was analyzed with actuarial methods.
| Results |
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Patients who received a prosthetic ring received short term (3 months) anticoagulation, no anticoagulation was prescribed to the other patients, unless atrial fibrillation or a prosthetic aortic valve were present.
After discharge, few morbid events were observed among hospital survivors. In 2 patients they suffered from endocarditis (one causing rupture of the reconstruction, see below), 1 patient had a major hemorragic event (gastrointestinal bleeding), 1 had onset of severe congestive heart failure, no patient experienced thromboembolic events.
Reoperation
No patient required early reoperation for residual MR or for mitral stenosis. There were three late reoperations for an overall freedom from reoperation of 95±4.8% at 6 years (
Fig. 3 ). One patient, whose anterior leaflet prolapse had been corrected with a double orifice repair and Carpentier ring implant, needed valve replacement 45 days after first operation because of severe hemolysis secondary to partial detachment of the prosthetic ring and trivial MR. One patient with erosion of the free edge of the anterior leaflet due to endocarditis, originally treated by double orifice repair, underwent valve replacement 9 months later for rupture of the E-to-E suture probably due to recurrent infection. One patient with preoperative bileaflet prolapse at the commissure, treated by paracommissural E-to-E repair, needed reoperation 3 years later for a new chordal rupture of the posterior leaflet which was successfully corrected by quadrangular resection. Freedom from reoperation at 6 years were 98±1.6% for the anterior leaflet prolapse, 86±13.2% for the bileaflet prolapse, 86±13.2% for lack of coaptation in absence of prolapse. No patient with preoperative posterior leaflet prolapse required reoperation in this series of patients.
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At follow-up transthoracic echocardiography (carried out in 87 patients), mean degree of MR was 0.4±0.83: 79 patients had no or trivial MR (91%); 5 (6%) had mild regurgitation; 1 (1%) had moderate MR; and 2 (2%) had severe MR. These 2 patients underwent reoperation and have been described above. Mean valve area at follow-up (by modified Bernoully method) was 3.0±0.97 cm2, not significantly different from the data obtained intraoperatively with transesophageal echo (P=0.1). Mitral valve area less than 2.5 cm2 was present in 9 patients, who had no clinical symptoms of mitral stenosis and a mean transvalvular gradient of 1.5±2.42 mmHg.
Functional status
Functional status at latest follow up was obtained in 114 patients: 63 patients (55%) were in NYHA class I; 36 (32%) were in class II; 12 (10%) were in class III; and 3 (3%) were in class IV. Functional class was not related to valve dysfunction, but it was dependent on preoperative left ventricular function.
| Discussion |
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Correction of anterior leaflet prolapse is more difficult than reconstruction of the posterior leaflet and it has been associated with less favorable outcome when triangular resection or chordal shortening were used [10] [4]. Although satisfactory results have been obtained with chordal transposition [3] [4] or artificial chordae replacement [11], both techniques are complex and undoubtedly surgically demanding.
In the presence of combined prolapse of the anterior and posterior leaflet, valve repair can be particularly cumbersome since chordal transfer from the anterior to the posterior leaflet is not always possible. Occasionally, the basal chordae of the prolapsing segment of the posterior leaflet can be used as part of the repair, alternatively, multiple chordal replacement is required. In a recent paper, Sousa Uva et al. [3] reported long aortic cross clamp times for the correction of bileaflet prolapse even though this situation was not identified as a risk factor for unfavorable outcome after the correction.
Equally demanding can be the correction of the prolapse of the commissural lesions, not rarely involving both leaflets, suboptimal results have been recently reported in this setting [5]. When the posterior annulus is extremely calcified, decalcification is required to allow annular plication for conventional quadrangular resection as described by El Asmar [7], but this maneuver is potentially dangerous, time consuming and not easily reproducible.
The E-to-E technique appears to be a simple and effective solution for the above mentioned complex situations. We used it extensively for the correction of anterior leaflet prolapse, since it is, in our experience, easier to carry out than other techniques and it allows good results, comparable with those obtained with chordal transfer or replacement (98±1.6% freedom from reoperation at 6 years). It is definitively a convenient alternative in case of bileaflet prolapse because both lesions can be easily corrected with a single surgical maneuver. It was successfully used also in case of Barlow disease with excellent results because double orifice repair corrected regurgitation and prevented systolic anterior movement of the anterior leaflet.
The E-to-E technique can be carried out in a short period of time, as demonstrated by the duration of cardiopulmonary bypass and aortic cross clamping in this series. This is particularly convenient when associated procedures are needed and in patients with poor preoperative conditions or with advanced left ventricular dysfunction. Due to its simplicity, the procedure can be reproducible with predictable results, even when the exposure of the valve is suboptimal due to a small left atrium.
Although in this series the E-to-E procedure has been predominantly used to treat MR due to prolapsing leaflets, it was successfully used to correct other types of valve dysfunction as well. In 4 patients, who had rheumatic disease and restricted leaflet motion and severe isolated MR, valvular competence was restored by approximating the free edges of the leaflets, usually associated to leaflet mobilization. Similarly, double orifice correction proved to be effective in ischemic MR, when the dysfunction was due to wall motion abnormalities.
The versatility of the E-to-E technique has allowed correction of MR in 18 selected patients with chronic or acute endocarditis. In these cases the procedure was usually used to resuspend flail leaflets or to promote coaptation when the flogistic process resulted in erosion and retraction of the free edges. Annular dilatation was corrected by autologous pericardium posterior annuloplasty in case of acute disease.
The great majority of patients had annular dilatation and deformation. We almost invariably associated an annuloplasty to the E-to-E repair, although Starling et al. [12] recently reported excellent mitral valve function with the double orifice technique alone after left ventricular reduction surgery for dilated cardiomyopathy.
The effectiveness of the E-to-E technique to repair MR as well as tricuspid valve insufficiency in selected patients has been reported by us previously [10] [13]. The present study, confirms the excellent early results and demonstrates the durability and stability of the repair over the 6 years of follow-up.
No mitral stenosis was documented in this series of patients, although with this technique the mitral orifice is always reduced. The mean postoperative area, determined by planimetric 2D echo, was 2.9±0.57 cm2 and persisted over time. No patient had a significant transvalvular gradient, we think however that this technique should be considered preferably in patients with preoperative annular dilatation.
Late mortality was unrelated to the operative technique or to mitral valve function and as expected, the incidence of late complications was low as in other series of patients treated with mitral reconstruction. Left ventricular dysfunction was the main determinant of the persistence of symptoms in the presence of a competent valve.
| Conclusion |
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| Footnotes |
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| Appendix A. Conference discussion |
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Dr. Maisano: The edge-to-edge technique is applicable even in case of bileaflet prolapse. As a matter of fact, in our series, 14 patients had prolapse of both leaflets in the setting of Barlow disease with elongation of the whole subvalvar apparatus. In all cases a double orifice repair, anchoring the leaflets right in the middle of the valve, was done with excellent results. The suture was 12 cm long. Post-operative valve areas were always larger than 2.5 cm2, since the preoperative ones were usually very large.
Dr. M. Zenati (Pittsburgh, PA): In your abstract you state that in no patient was there any residual mitral stenosis after this edge-to-edge. Do you have any data to support this statement?
Dr. Maisano: Obviously, the edge-to-edge technique reduces the valve area. Nevertheless, post-operative valve area was about 3 cm2. Noteworthy, the technique was reserved only to patients with a large preoperative valve annulus, especially when a double orifice repair was needed to correct the MR. At the end of reconstruction, 9 patients had a valve area less than 2.5 cm2. These patients have no symptoms at the latest follow-up and the mean gradient by echocardiography is less than 5 mmHg.
Dr. C. Alhan (Istanbul, Turkey): Is a friable leaflet a limitation for this technique? Also, what was the reason for 2 patients having large regurgitation?
Dr. Maisano: In the presence of thin leaflets we prefer to add one or two mattress sutures with pericardial pledgets to reinforce the reconstruction. Regarding the causes of reoperation: 1 patient was reoperated on because of hemolysis due to detachment of the Carpentier ring without mitral regurgitation; 1 patient had severe regurgitation because of a new chordal rupture; the third reoperation was done in a patient who had received a double orifice repair in the setting of acute endocarditis associated with free edge erosion. At reoperation we found complete rupture of the reconstruction which could be secondary to the infection or to high tension on the suture line.
Dr. J. Pomar (Barcelona, Spain): One of the points with this technique is that it is going to have two different orifices and there is going to be a distortion of the flow; at least it is not going to be a natural flow. We also know that this can be an incremental risk for endocarditis. And, of course, also for a new problem due to fibrosis of the tissue. Could you elaborate a little bit further on this?
Dr. Maisano: One of our concerns was the possible development of fibrosis in the area of leaflet approximation, but, as you have seen from our results, the mitral valve area remained stable over time. This suggests no tendency toward fibrosis. Regarding the supposed altered intraventricular flow, we had no patients experiencing thromboembolic events, but I do not have the answer to this good question which suggests an intriguing and interesting field of investigation.
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