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Initial clinical experience with Myxo-ETlogix mitral valve repair ring

      Objective

      Complexity of mitral valve repair for myxomatous disease has led to low adoption. We report initial experience with a new ring designed specifically for myxomatous disease, the Myxo-ETlogix (Edwards Lifesciences LLC, Irvine, Calif).

      Methods

      From March 15, 2006, through November 19, 2007, 129 patients underwent mitral valve surgery for pure myxomatous disease, and 124 valves (96.1%) were repaired. The Myxo-ETlogix ring was used in 100 cases and the Physio ring (Edwards) in 24. The Myxo-ETlogix design includes a 3-dimensional shape to reduce systolic anterior motion and a larger orifice to accommodate elongated leaflets and decrease need for sliding plasty. Direct mitral valve measurements were made. Sizing was based on A2 height, and choice of ring type was based on unresected leaflet heights.

      Results

      There was no operative mortality or lasting perioperative morbidity. The Myxo-ETlogix group had taller A2, P1, P2, and P3 leaflet segments than the Physio group (P ≤ .003). Only 1 sliding plasty was performed for asymmetry in the Myxo-ETlogix group. Predischarge and follow-up echocardiograms (n = 338 in 124 patients) disclosed transient nonobstructive chordal systolic anterior motion in 3 echocardiograms in 3 patients. No patients had 2+ or greater mitral regurgitation. At discharge, 5.7% had 1+ mitral regurgitation; this proportion was 17.3% at last follow-up (mean 6.1 ± 4.4 months).

      Conclusion

      In initial experience with the Myxo-ETlogix ring, nonobstructive systolic anterior motion has been rare and obstructive systolic anterior motion not observed. Ongoing prospective echocardiographic and clinical studies will elucidate the role of this etiology-specific ring.

      Abbreviations and Acronyms:

      MR (mitral regurgitation), MV (mitral valve), SAM (systolic anterior motion)

      CTSNet classification

      Mitral valve (MV) prolapse is common, occurring in 1% to 2.5% of the population.
      • American College of Cardiology/American Heart Association Task Force on Practice Guidelines
      • Society of Cardiovascular Anesthesiologists
      • Society for Cardiovascular Angiography and Interventions
      • Society of Thoracic Surgeons
      • Bonow R.O.
      • Carabello B.A.
      • et al.
      ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons.
      Myxomatous mitral regurgitation (MR) is characterized by elongation and thickening of the valve leaflets with annular and dilatation prolapse (Carpentier type II).
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Filsoufi F.
      Current concepts in mitral valve repair for degenerative disease.
      Numerous studies have demonstrated that mitral repair generally gives a more favorable result than does MV replacement, but because of the complexity of the pathology and therefore the procedure required, it is performed in fewer than 50% of cases according to data from the United States and Europe.
      • Braunberger E.
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      Very long-term results (more than 20 years) of valve repair with Carpentier's techniques in nonrheumatic mitral valve insufficiency.
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      • Ferguson Jr., T.B.
      • DiSesa V.J.
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      Survival advantage and improved durability of mitral repair for leaflet prolapse subsets in the current era.
      Furthermore, the considerable interpatient variability has required the surgeon to approach valve repair as an art, and valve repair has been concentrated such that a minority of surgeons perform the majority of repairs. Consequently, it has been difficult for a low- or medium-volume mitral repair surgeon to develop the numerous skills necessary for successful repair, considering the wide variety of surgical techniques that may be required for complex repairs.
      An additional repair problem specific to myxomatous disease is the development of systolic anterior motion (SAM), which has been reported in 2% to 16% of patients after mitral repair.
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Abascal V.
      • Salzberg S.P.
      • Filsoufi F.
      Large annuloplasty rings facilitate mitral valve repair in Barlow's disease.
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      • Levine R.A.
      Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease.
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      • et al.
      Left ventricular outflow obstruction after mitral valve repair (Carpentier's technique). Proposed mechanisms of disease.
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      • Acar C.
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      • Latremouille C.
      • et al.
      Left ventricular outflow tract obstruction after mitral valve repair. Results of the sliding leaflet technique.
      Transient SAM may be seen during first weaning from cardiopulmonary bypass and may be easily treated by volume infusion from the pump to increase the systemic blood pressure (afterload) if the patient is hypotensive and vasodilated and by stopping positive inotropes. More troublesome is persistent SAM, which may require additional medical or surgical therapy. SAM is precipitated by elongated leaflets and may cause left ventricular outflow tract obstruction and residual or recurrent MR. SAM may be caused by a short distance between the point of leaflet coaptation to the nearest point on the ventricular septum, which may be seen when the posterior leaflet is too tall or the annuloplasty ring placed is too small.
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Abascal V.
      • Salzberg S.P.
      • Filsoufi F.
      Large annuloplasty rings facilitate mitral valve repair in Barlow's disease.
      • Maslow A.D.
      • Regan M.M.
      • Haering J.M.
      • Johnson R.G.
      • Levine R.A.
      Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease.
      An elongated anterior leaflet may also contribute to SAM, and numerous techniques can be used to avoid or eliminate SAM, such as shortening the anterior leaflet, creating a double orifice (edge-to-edge approximation), or even myectomy.
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Filsoufi F.
      Current concepts in mitral valve repair for degenerative disease.
      • Deloche A.
      • Jebara V.A.
      • Relland J.Y.
      • Chauvaud S.
      • Fabiani J.N.
      • Perier P.
      • et al.
      Valve repair with Carpentier techniques. The second decade.
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      • Tripodi A.
      • Mebazaa A.
      • et al.
      Edge-to-edge technique to treat post-mitral valve repair systolic anterior motion and left ventricular outflow tract obstruction.
      • Quigley R.L.
      Prevention of systolic anterior motion after repair of the severely myxomatous mitral valve with an anterior leaflet valvuloplasty.
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      • McCarthy P.M.M.
      • Smedira N.G.
      • Lam B.K.
      • Rajeswaran J.
      • Blackstone E.H.
      Edge-to-edge (Alfieri) mitral repair: results in diverse clinical settings.
      • Civelek A.
      • Szalay Z.
      • Roght M.
      • Arnold R.
      • Klövekorn W.P.
      • Vogt P.R.
      • et al.
      Post-mitral valve repair systolic anterior motion produced by non-obstructive septal bulge.
      • Raney A.A.
      • Shah P.M.
      • Joyo C.I.
      The ‘Pomeroy procedure’: a new method to correct post-mitral valve repair systolic anterior motion.
      Reducing the height of the posterior leaflet (sliding plasty) is the most common technique.
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Filsoufi F.
      Current concepts in mitral valve repair for degenerative disease.
      • Jebara V.A.
      • Mihaileanu S.
      • Acar C.
      • Brizard C.
      • Grare P.
      • Latremouille C.
      • et al.
      Left ventricular outflow tract obstruction after mitral valve repair. Results of the sliding leaflet technique.
      • Zegdi R.
      • Carpentier A.
      • Doguet F.
      • Berrebi A.
      • Khabbaz Z.
      • Chauvaud S.
      • et al.
      Systolic anterior motion after mitral valve repair.
      Although some would argue that SAM may be managed medically with long-term β-blocker therapy and a low late need for reoperation, persistent SAM may be associated with continuing MR, and a young patient requiring long-term β-blocker therapy has had an imperfect operation.
      • Brown M.L.
      • Abel M.D.
      • Click R.L.
      • Morford R.G.
      • Dearani J.A.
      • Sundt T.M.
      • et al.
      Systolic anterior motion after mitral valve repair: is surgical intervention necessary?.
      • Schiavone W.A.
      • Cosgrove D.M.
      • Lever H.M.
      • Steward W.J.
      • Salcedo E.E.
      Long-term follow-up of patients with left ventricular outflow tract obstruction after Carpentier ring mitral valvuloplasty.
      In an age when surgery is being performed early, in symptom-free patients, this result is less than ideal.
      • American College of Cardiology/American Heart Association Task Force on Practice Guidelines
      • Society of Cardiovascular Anesthesiologists
      • Society for Cardiovascular Angiography and Interventions
      • Society of Thoracic Surgeons
      • Bonow R.O.
      • Carabello B.A.
      • et al.
      ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons.
      Ideally, the repair procedure would avoid SAM altogether and not require long-term medical management.
      We sought to develop a new MV repair ring designed to accommodate the specific pathologic conditions of myxomatous disease. This etiology-specific ring, the Myxo-ETlogix (Edwards Lifesciences LLC, Irvine, Calif) ring has a larger orifice than does a Physio (Edwards Lifesciences) ring (which is based on normal anatomy) to accommodate the elongated leaflets. It also has a 3-dimensional shape that moves the coaptation point away from the septum (increasing the distance between the point of leaflet coaptation to the nearest point on the ventricular septum), thereby reducing the risk of SAM.
      • Maslow A.D.
      • Regan M.M.
      • Haering J.M.
      • Johnson R.G.
      • Levine R.A.
      Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease.
      • Bhudia S.K.
      • McCarthy P.M.M.
      • Smedira N.G.
      • Lam B.K.
      • Rajeswaran J.
      • Blackstone E.H.
      Edge-to-edge (Alfieri) mitral repair: results in diverse clinical settings.
      Because this etiology-specific ring has a larger orifice, a secondary advantage would be that extensive leaflet reconstruction to reduce the size of the leaflets back to “normal” (sliding plasty) would not be needed, or at least would be needed much less frequently. This would reduce the complexity of myxomatous valve repair and ideally make it more generalizable. Furthermore, the larger orifice leads to a low or normal gradient. This is the first report of the concepts behind the new Myxo-ETlogix, the impact that it had on our use of other mitral repair rings and techniques, and the initial clinical results.

      Materials and Methods

      Patient Characteristics

      Patient information and follow-up data were obtained from the prospectively maintained cardiac surgery outcomes registry of the Bluhm Cardiovascular Institute, which was approved by the Northwestern University Institutional Review Board for use in research. The study ran from the date of first use of Myxo-ETlogix (March 15, 2006) until the date of 100th Myxo-ETlogix implant (November 19, 2007). For the purposes of this study, we analyzed only those patients with MR caused by isolated myxomatous degenerative MV disease (n = 129). The diagnosis of myxomatous disease was determined by echocardiographic and surgical findings of elongated MV leaflets with prolapse (type II). Patients were excluded if they had rheumatic valve disease, ischemic valve disease, cardiomyopathy, endocarditis, or mixed pathology. Among the 129 myxomatous MR cases, MV repair was performed in 124 patients (96.1%), and MV replacement was performed in 5 patients (3.9%). These 5 patients had ages of 65, 72, 74, 78, and 84 years, and all had annular and leaflet calcification. Patients included in this analysis were operated on by two surgeons at a single institution, Northwestern Memorial Hospital.
      In the repair group, 100 patients received the Myxo-ETlogix annuloplasty ring, which is a Food and Drug Administration–approved ring for patients undergoing MV repair. During the same period, the Carpentier–Edwards Physio ring was used to repair 24 valves in patients with myxomatous MV disease. Thus 80.6% of the patients with myxomatous disease underwent repair with the Myxo-ETlogix ring, and 19.4% underwent repair with a Physio ring. According to our practice, all patients in the group were prospectively followed up by a specific valve nurse who was available to answer patient questions, arrange follow-up visits, and facilitate entry into prospective 3-dimensional echocardiographic and other imaging studies. The characteristics of the patients who received the Myxo-ETlogix ring are compared with those of the patients who received a Physio ring in Table 1. Overall, the age of the patients was 57 ± 13 years, and the Myxo-ETlogix patients were younger (P = .047). The Myxo-ETlogix patients had more MR (97% with 4+, P < .001). Other significant differences between the groups included smaller body mass index and more white patients in the Myxo-ETlogix group (patient self-report), whereas patients in the Physio group were more likely to have chronic obstructive pulmonary disease. The 5 patients who underwent MV replacement were significantly older than the 124 repair patients (P < .001), and their operative findings precluded safe, durable MV repair. All these patients underwent valve replacement with a bioprosthetic bovine pericardial valve. In keeping with the trend toward early repair in patients with myxomatous MV disease, most of the patients in the repair group were in New York Heart Association functional class I or II (81.4%).
      Table 1Preoperative patient characteristics by annuloplasty type
      Total (N = 124)Physio (n = 24)Myxo-ETlogix (n = 100)P value
      Age (y).047
      Squared transformation.
       Mean ± SD57.4 ± 13.462.2 ± 12.156.2 ± 13.5
       Range22–8541–8122–85
       Male (No.)76 (61.2%)14 (58.3%)62 (62.0%)NS
      Body mass index (kg/m2).006
      Natural log transformation.
       Mean ± SD25.4 ± 4.527.6 ± 3.924.9 ± 4.5
       Range15.1–39.520.2–34.215.1–39.5
       White race (No.)103 (83.1%)16 (66.7%)87 (87.0%).017
       Previous cardiac surgery (No.)1 (0.8%)0 (0.0%)1 (1.0%)NS
      Comorbidities (No.)
       Previous myocardial infarction2 (1.6%)1 (4.2%)1 (1.0%)NS
       Congestive heart failure16 (12.9%)5 (20.8%)11 (11.0%)NS
       Coronary artery disease19 (15.3%)4 (16.7%)15 (15.0%)NS
       Diabetes3 (2.4%)0 (0.0%)3 (3.0%)NS
       Hypertension (systemic)48 (38.7%)13 (54.2%)35 (35.0%).083
       Hypertension (pulmonary)65 (52.9%)13 (54.2%)52 (52.0%)NS
       Renal failure0 (0.0%)0 (0.0)0 (0.0)NS
       Chronic obstructive pulmonary disease8 (6.5%)4 (16.7%)4 (4.0%).045
      Fisher exact test.
       Hyperlipidemia40 (32.3%)9 (37.5%)31 (31.0%)NS
       Atrial fibrillation or flutter26 (21.0%)7 (29.2%)19 (19.0%)NS
      New York Heart Association functional class (No.)NS
       I35 (28.2%)4 (16.7%)31 (31.0%)
       II66 (53.2%)13 (54.2%)53 (53.0%)
       III–IV23 (18.6%)7 (29.2%)16 (16.0%)
      Prolapse (No.)NS
       Anterior8 (6.5%)2 (8.7%)6 (6.0%)
       Posterior83 (67.5%)19 (82.6%)64 (64.0%)
       Anterior and posterior32 (26.0%)2 (8.7%)30 (30.0%)
      Preoperative echocardiographic mitral regurgitation (No.)<.001
       2+2 (1.6%)2 (8.3%)0 (0.0%)
       3+7 (5.7%)4 (16.7%)3 (3.0%)
       4+115 (92.7%)18 (75.0%)97 (97.0%)
      LV ejection fraction (%)NS
       Mean ± SD59.4% ± 7.5%60.7% ± 7.0%59.1% ± 7.6%
       Range35%–80%50%–80%35%–75%
      LV end-systolic dimension (cm)NS
       Mean ± SD3.6 ± 0.63.6 ± 0.63.6 ± 0.6
       Range2.1–5.12.3–4.42.1–5.1
      LV end-diastolic dimension (cm)NS
       Mean ± SD5.5 ± 0.75.5 ± 0.65.5 ± 0.7
       Range3.9–7.14.3–6.53.9–7.1
      NS, not significant (P > .20); LV, left ventricular.
      Squared transformation.
      Natural log transformation.
      Fisher exact test.

      Characteristics of the Myxo-ETlogix Ring

      The Myxo-ETlogix ring was designed as a complete annular remodeling ring with etiology-specific variations from the Physio ring (Figure 1).
      • Carpentier A.F.
      • Lessana A.
      • Relland J.Y.
      • Belli E.
      • Mihaileanu S.
      • Berrebi A.J.
      • et al.
      The “physio-ring”: an advanced concept in mitral valve annuloplasty.
      The anteroposterior dimension of the ring was increased 29% to accommodate elongated myxomatous leaflets. Depending on the exact size of the ring, this led to an increase in anteroposterior diameter of 5 to 8 mm, designed to correspond to typical reduction in posterior leaflet height in patients who undergo sliding plasty. Rather than the surgeon performing extensive reconstruction to reduce the height of the posterior leaflet by 5 to 8 mm, instead the ring pulls the posterior leaflet down by a corresponding amount. This also creates a 16% increase in the total orifice area for the Myxo-ETlogix ring. The largest anteroposterior diameter of a size 40 Physio ring is 27.2 mm, which corresponds most closely to a size 32 Myxo-ETlogix ring (28.0 mm). A size 40 Myxo-ETlogix ring has an anteroposterior diameter of 35.0 mm. The Myxo-ETlogix ring was only available in sizes 26 through 36 until mid November 2006, when sizes 38 and 40 became available but sizes 26 and 28 became unavailable. This shortage was due to production of a limited quantity of early rings.
      Figure thumbnail gr1
      Figure 1Myxo-ETlogix ring designed for patients with leaflet elongation historically treated with sliding plasty with risk of systolic anterior motion. Ring has longer anteroposterior diameter (typically 6 mm) to accommodate larger leaflets, corresponding to typical posterior leaflet height reduction from sliding plasty. P2 segment of ring has 4-mm displacement into annulus. Net effect of these two changes moves coaptation point down and away from septum, reducing risk of systolic anterior motion.
      In addition to accommodating the larger leaflets, the Myxo-ETlogix ring was designed to move the coaptation point down, and also away from the septum, by means of a 4-mm shape change centered at the P2 region, pulling the ring into the left atrium (Figure 1) and resulting in an increase in the distance between the point of leaflet coaptation to the nearest point on the ventricular septum. The net effect of these two changes is to pull the coaptation point down and away from the septum.

      Operative Techniques

      Operative techniques were largely based on Carpentier's time-tested concepts of resection of the prolapsing segment, chordal transfer if necessary, leaflet reconstruction, and complete remodeling annuloplasty ring.
      • Braunberger E.
      • Deloche A.
      • Berrebi A.
      • Abdallah F.
      • Celestin J.A.
      • Meimoun P.
      • et al.
      Very long-term results (more than 20 years) of valve repair with Carpentier's techniques in nonrheumatic mitral valve insufficiency.
      • Carpentier A.F.
      • Lessana A.
      • Relland J.Y.
      • Belli E.
      • Mihaileanu S.
      • Berrebi A.J.
      • et al.
      The “physio-ring”: an advanced concept in mitral valve annuloplasty.
      The Myxo-ETlogix ring was used for patients with elongated anterior leaflets or tall remaining posterior leaflet segments after resection. If the remaining posterior and anterior leaflets were normal after resection, then a Physio ring was used. Repair techniques for both groups included leaflet resection, chordal transfer, commissuroplasty, and ring annuloplasty. No artificial chords were used in any patients. Before the Myxo-ETlogix ring was available, sliding annuloplasty was performed in 38% of cases of myxomatous disease (according to our database) when the remaining posterior segments were longer than 20 mm by visual inspection (not by direct measurement, which was not yet available) and sometimes when the posterior leaflet was shorter than 20 mm but there was a wide resection.
      Concomitant cardiac surgical procedures (Table 2) included a maze procedure in 31 patients (25%), tricuspid valve annuloplasty in 12 patients (9.7%), coronary artery bypass grafting in 17 patients (13.7%), and aortic valve replacement in 3 patients (2.4%). There was no difference in concomitant procedures between the Physio and Myxo-ETlogix groups, but the ring size used in the Myxo-ETlogix group was larger (P = .001). The 1 patient (in the Myxo-ETlogix group) who underwent sliding plasty had an unresected remnant P2 height of 27 mm and a P3 height of 16 mm. Because of the extensive size discrepancy and a wide resection (22 mm), the height of the remaining P2 was reduced with a short sliding plasty. A second pump run was performed in 2 cases (1.6%) because of residual MR (1+–2+), with conversion from repair to replacement in an 84-year-old patient and successful additional leaflet repair in another patient.
      Table 2Operative results
      Total (N = 124)Physio (n = 24)Myxo-ETlogix (n = 100)P value
      Ring size (mm).001
       Mean ± SD33.0 ± 3.431.1 ± 2.633.5 ± 3.4
       Range26–4026–3626–40
       Resection (No.)110 (88.7%)20 (83.3%)90 (90.0%)NS
      Width of resection (mm)<.001
       Mean ± SD15.5 ± 6.411.3 ± 3.516.6 ± 6.5
       Range7–367–207–36
       Sliding plasty (No.)0 (0.8)%0 (0.0%)1 (1.0%)NS
       Chordal transfer (No.)20 (16.1%)1 (4.2%)19 (19.0%).119
      Fisher exact test.
      Crossclamp time (min).195
      Natural log transformation.
       Mean ± SD88.1 ± 22.783.5 ± 24.189.2 ± 22.3
       Range52–16952–13855–169
      Cardiopulmonary bypass time (min)NS
       Mean ± SD104.7 ± 26.1101.0 ± 26.5105.6 ± 26.0
       Range67–19067–15967–190
       Commissuroplasty (No.)7 (5.7%)0 (0.00%)7 (7.0%)NS
      Concomitant procedures (No.)
       Coronary artery bypass grafting17 (13.7%)3 (12.5%)14 (14.0%)NS
       Atrial valve replacement3 (2.4%)0 (0.00%)3 (3.0%)NS
       Tricuspid valve annuloplasty12 (9.7%)1 (4.2%)11 (11.0%)NS
       Maze31 (25.0%)8 (33.3%)23 (23.0%)NS
      Postoperative
       Mortality, infection, myocardial infarction, or acute renal failure (No.)0 (0.0%)0 (0.0%)0 (0.0%)NS
       Reoperation for bleeding (No.)1 (0.8%)0 (0.0%)1 (1.0%)NS
       Cerebrovascular accident (No.)1 (0.8%)0 (0.0%)1 (1.0%)NS
      Hospital stay (d)NS
       Mean ± SD5.8 ± 2.96.0 ± 2.65.6 ± 2.9
       Range3–244–153–24
      Intraoperative echocardiography
       Mitral regurgitation (No.)NS
        0121 (97.6%)23 (95.8%)98 (98.0%)
        1+3 (2.4%)1 (4.2%)2 (2.0%)
       Mean gradient (mm Hg)NS
        Mean ± SD3.1 ± 1.53.3 ± 1.93.0 ± 1.4
        Range0.6–10.01.4–10.00.6–9.0
      Predischarge echocardiography
       Mitral regurgitation (No.)NS
        0115 (92.7%)23 (95.8%)92 (93.9%)
        1+7 (5.7%)1 (4.2%)6 (6.1%)
       Mean gradient (mm Hg).134
      Natural log transformation.
        Mean ± SD3.3 ± 1.43.7 ± 1.73.2 ± 1.4
        Range1.2–8.61.5–8.01.2–8.6
      NS, Not significant.
      Fisher exact test.
      Natural log transformation.

      Direct MV Measurements and Choice of Myxo-ETlogix Versus Physio Ring

      Direct measurements of the MV were taken with a custom-designed set of measuring calipers. These distance measurements included commissure-to-commissure, trigone-to-trigone, and heights of the leaflet at P1, P2, P3, and A2 segments (Figure 2). Other measurements included width of the resected segment, width of the annulus after compression sutures, height of the middle segment of the posterior leaflet after reconstruction when applicable, and overlaps at P1, P2, P3, A1, A2, and A3. The results of these measurements are depicted in Figure 2. Table 3 compares the measures in patients with Myxo-ETlogix rings with those of patients with Physio rings. Measurements were available for 98 of 100 patients in the Myxo-ETlogix group and 22 of 24 patients in the Physio group.
      Figure thumbnail gr2
      Figure 2Direct measurement with custom calipers provided quantitative data on leaflet length in different segments documenting elongated leaflets in bell-shaped frequency curve. In particular, A2 height was very elongated; this was used to choose appropriate ring type (Physio ring vs Myxo-ETlogix ring) and ring size.
      Table 3Direct preoperative and postoperative mitral valve measurements
      Measurement (mm)TotalPhysio (n = 22)Myxo-ETlogix (n = 98)P value
      A2<.001
       Mean ± SD27.9 ± 4.923.7 ± 5.228.9 ± 4.3
       Range15-4117-3415-41
      P1<.001
       Mean ± SD13.6 ± 4.310.6 ± 2.914.3 ± 4.3
       Range6-276-206-27
      P2.003
       Mean ± SD21.9 ± 5.119.0 ± 4.622.5 ± 5.0
       Range7-349-307-34
      P-middle
      P-middle is the height of the leaflet after P2 resection and reconstruction.
      <.001
       Mean ± SD14.6 ± 2.912.3 ± 1.915.1 ± 2.8
       Range8-2310-168-23
      P3<.001
       Mean ± SD15.1 ± 3.812.5 ± 2.615.7 ± 3.8
       Range6-248-186-24
      Cusp-to cusp.007
       Mean ± SD38.1 ± 6.035.0 ± 4.338.8 ± 6.2
       Range27-5127-4527-51
      Trigone-to-trigone.023
       Mean ± SD24.6 ± 4.222.8 ± 3.425.0 ± 4.3
       Range14-3616-2814-36
      P2 overlap.003
       Mean ± SD6.5 ± 1.95.4 ± 1.46.8 ± 1.9
       Range2-134-92-13
      A2 overlap.070
       Mean ± SD5.7 ± 1.95.0 ± 1.65.8 ± 1.9
       Range2-113-92-11
      P-middle is the height of the leaflet after P2 resection and reconstruction.
      Ring size was chosen according to A2 height. The measurement was referenced to a chart of the anteroposterior diameter of Myxo-ETlogix and Physio rings. Ring size was true sized to A2 height in most cases. Occasionally, a larger Myxo-ETlogix ring was chosen because of an unusually tall (>20 mm) posterior leaflet, a smaller Myxo-ETlogix ring was chosen if there was a short posterior leaflet (<12 mm), or another size was chosen if the closest ring size was not available. Other measurements or judgments (commissure-to-commissure, trigone-to-trigone, anterior leaflet surface area) were not used for sizing.
      The Physio ring was used for the subset of patients who had what Carpentier classifies as “fibroelastic deficiency.”
      • Fornes P.
      • Heudes D.
      • Fuzellier J.F.
      • Tixier D.
      • Bruneval P.
      • Carpentier A.
      Correlation between clinical and histologic patterns of degenerative mitral valve insufficiency: a histomorphometric study of 130 excised segments.
      This group tended to be older, with associated comorbidities such as hypertension and chronic obstructive pulmonary disease, and the pathologic characteristics typically consisted of ruptured chords at the P2 segment with normal lengths of P1, P3, and A2. The pathology at P2 was resected, and the remaining valve leaflet lengths were therefore normal, so the Physio ring was chosen as a design based on normal valve anatomy.
      • Jebara V.A.
      • Mihaileanu S.
      • Acar C.
      • Brizard C.
      • Grare P.
      • Latremouille C.
      • et al.
      Left ventricular outflow tract obstruction after mitral valve repair. Results of the sliding leaflet technique.
      Patients who received a Myxo-ETlogix ring consisted of those with Barlow disease and those with lengthening of unresected segments of the leaflet, the anterior leaflet, or both. Most patients did not fall into two distinct categories (Barlow disease vs fibroelastic deficiency) and instead had more intermediate leaflet length, as depicted in Figure 2.

      Echocardiographic Techniques

      MR was assessed as follows: none or trivial, 0; mild, 1+; moderate, 2+; moderate to severe, 3+; and severe, 4+. Nonobstructive (chordal) SAM was defined as anterior motion of the MV or subvalvular apparatus without an elevation of the peak velocity or a late peaking velocity profile in the Doppler waveforms in the left ventricle or left ventricular outflow tract. Echocardiography was performed in 100% of patients intraoperatively, at discharge, and, according to our usual practice, at approximately 1 month and between 3 and 6 months after surgery, annually, and any other time as clinically indicated.

      Statistical Analysis

      Demographic and clinical patient characteristics in the Physio and Myxo-ETlogix groups were compared with t tests for continuous variables and χ2 tests for categorical variables. Group differences in intraoperative variables were evaluated with the same methodology. Continuous variables were appropriately transformed if a better approximation of normal distribution could be achieved. Fisher exact test was used for comparisons of categorical variables with a minimum cell count of 5 or less.

      Results

      Postoperative complications were low, with no deaths, no infections, no perioperative infarctions, 1 reoperation for bleeding (0.8%), and 1 stroke on postoperative day 3 from atrial fibrillation that resolved before discharge. Follow-up was 100% complete, and there were no late deaths.
      Predischarge and follow-up echocardiograms totaled 338. No MR or trivial MR was present at discharge in 92.7% of patients, and 1+ was present in 5.7% (Table 2). Mean gradient at discharge showed a trend toward being higher in the Physio group (3.7 ± 1.7 mm Hg vs 3.2 ± 1.4 mm Hg, P = .134, natural log transformation to normalize the data). At most recent follow-up (mean 6.1 ± 4.4 months) 1+ MR was present in the Physio group in 1 patient (10%) and in the Myxo-ETlogix group in 16 patients (18%, differences from baseline and between groups not significant). There was no significant difference between MR at discharge and last follow-up. No patients had 2+ or greater MR.
      After surgery, no obstructive SAM was seen, and nonobstructive chordal SAM was inconsistently seen in 3 patients. In 1 patient (with a 32-mm Myxo-ETlogix valve), SAM was first detected 14 days after discharge, but subsequent echocardiograms on days 82, 214, and 397 had negative results. In a second patient (with a 36-mm Myxo-ETlogix valve), there was no SAM early (predischarge or day 12 after discharge), SAM was recorded on day 160 after discharge, and at 1-year follow-up there was no SAM. In a third patient (with a 34-mm Physio ring), discharge echocardiography showed chordal SAM; this patient has not yet returned for follow-up. Transient intraoperative SAM shortly after weaning from bypass was uncommon (3 patients), depended on volume status and blood pressure, and never required a second pump run or revision. One patient (with a 28-mm Myxo-ETlogix valve with commissuroplasty) had an early uneventful course after repair, with a low gradient (3.5 mm Hg), but had an intense, generalized inflammatory reaction, including both mitral leaflets, and required reoperative MV replacement for mitral stenosis 13 months after repair. Table 2 summarizes operative results for both groups.

      Discussion

      Overall, in an age of early repair for myxomatous disease, our results demonstrated a safe operation with low morbidity, a high rate of repair (96%), and excellent early results with little residual or recurrent MR (none at least 2+). We have found clinical benefit in precise anatomic measurement of the pathologic tissue, and these data drive our choice of ring size and type of ring prosthesis. This has led to predictable coaptation of the leaflets, without rings or residual leaflet heights we considered too small or too big. Our data indicate that although some patients' leaflets fall into the extremes of Barlow disease versus fibroelastic deficiency, most patients' leaflet lengths fall somewhere between these extremes. Although an artistic, creative approach to complex valve problems with many different techniques is still valuable, we hope to move toward a more standardized, generalizable, reproducible repair that will lead to higher repair rates. Our current approach includes three steps: (1) trapezoidal resection (mean 15.5 ± 6.4 mm) of prolapsing posterior leaflet segments with chordal transfer to extensive anterior prolapsing segments if needed, (2) ring choice and sizing that is based on A2 and remaining posterior leaflet heights, and (3) complete remodeling annuloplasty with a Physio ring for normal remaining leaflets or with a Myxo-ETlogix ring for elongated leaflets. Although sliding plasty (and other complex techniques) should not be forgotten, in our institution we reduced the use of sliding plasty from 38% before this series to less than 1% in this experience. After reconstruction, the ratio of A2 height to posterior leaflet was 1.9 in both groups, which is thought to be optimal. Others routinely use resection without sliding plasty, but SAM does appear to be more common in those series than in ours (2.4% transient nonobstructive SAM and SAM without left ventricular outflow tract obstruction).
      • Brown M.L.
      • Abel M.D.
      • Click R.L.
      • Morford R.G.
      • Dearani J.A.
      • Sundt T.M.
      • et al.
      Systolic anterior motion after mitral valve repair: is surgical intervention necessary?.
      • Gazoni L.M.
      • Fedoruk L.M.
      • Kern J.A.
      • Dent J.M.
      • Reece T.B.
      • Tribble C.G.
      • et al.
      A simplified approach to degenerative disease: triangular resections of the mitral valve.
      Quantitative data, other than from echocardiograms, have been hard to find in mitral repair series. Use of the Adams “ink test” and direct measurement of valve segments should help standardize our results and make it easier to compare results from different series.
      • Anyanwu A.C.
      • Adams D.H.
      The intraoperative “ink test”: a novel assessment tool in mitral valve repair.
      • Adams D.H.
      • Anyanwu A.C.
      Pitfalls and limitations in measuring and interpreting the outcomes of mitral valve repair.
      • Bridgewater B.
      • Hooper T.
      • Munsch C.
      • Hunter S.
      • von Oppell U.
      • Livesey S.
      • et al.
      Mitral repair best practice: proposed standards.
      All these points are important, because we now see symptom-free patients for whom the guidelines recommend repair at experienced centers if there is a greater than 90% chance of repair without residual MR.
      • American College of Cardiology/American Heart Association Task Force on Practice Guidelines
      • Society of Cardiovascular Anesthesiologists
      • Society for Cardiovascular Angiography and Interventions
      • Society of Thoracic Surgeons
      • Bonow R.O.
      • Carabello B.A.
      • et al.
      ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons.
      • Adams D.H.
      • Anyanwu A.C.
      Pitfalls and limitations in measuring and interpreting the outcomes of mitral valve repair.
      • Bridgewater B.
      • Hooper T.
      • Munsch C.
      • Hunter S.
      • von Oppell U.
      • Livesey S.
      • et al.
      Mitral repair best practice: proposed standards.
      Large annuloplasty rings have been recommended for patients with Barlow disease.
      • Adams D.H.
      • Anyanwu A.C.
      • Rahmanian P.B.
      • Abascal V.
      • Salzberg S.P.
      • Filsoufi F.
      Large annuloplasty rings facilitate mitral valve repair in Barlow's disease.
      We agree that this is an important consideration, and more practical than bileaflet resection or reconstruction to reduce leaflet height. The new Myxo-ETlogix ring, designed for these patients, is significantly larger than existing commercial remodeling rings. Barlow disease is not a distinct entity in most cases, however, and even histologic studies have shown a large group of disorders intermediate between Barlow disease and fibroelastic deficiency.
      • Fornes P.
      • Heudes D.
      • Fuzellier J.F.
      • Tixier D.
      • Bruneval P.
      • Carpentier A.
      Correlation between clinical and histologic patterns of degenerative mitral valve insufficiency: a histomorphometric study of 130 excised segments.
      Whereas some surgeons may describe Barlow disease in 1% of patients, others may use that term to describe 50% of their patients with degenerative disease. Furthermore, our data show that some patients may have an elongated A2 segment but normal posterior segments, or vice versa. The choice of a large ring thus is variable by surgeon. Although the average A2 height in our series (29 mm) corresponds most closely to a 34 Myxo-ETlogix ring, larger than the largest Physio ring (27 mm), we commonly used smaller Myxo-ETlogix rings instead of large Physio rings because of the perceived benefit of the 4-mm P2 displacement with the Myxo-ETlogix ring to reduce the risk of SAM. Whether it is the P2 displacement or the large size of the Myxo-ETlogix ring that accounts for our low incidence of SAM is not yet clear.

      Study Limitations

      This was a nonrandomized study of the initial use of a new commercially available ring, but not all ring sizes were available during the study period. The inventor of the ring was the surgeon in the vast majority of cases, and we attempted to reduce this bias with direct quantitative measurements and standard echocardiographic reporting. The data in all tables and figures therefore represent unbiased measurements and clinical results. A randomized trial is certainly feasible but would be best performed at another institution, albeit with experienced surgeons.
      In summary, a new ring was introduced with a change in our clinical practice. The result was simpler MV repair procedures, rare nonobstructive SAM, and excellent clinical and echocardiographic results. Further confirmation at other centers is pending, and late echocardiographic follow-up is ongoing.

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