MMCTS
(August 10, 2006). doi:10.1510/mmcts.2004.000950
Copyright © 2006 European Association for Cardio-thoracic Surgery
Procedure
Open mitral commissurotomy
Manuel J. Antunes*
Cardiothoracic Surgery, University Hospital, Coimbra 3000, Portugal
* Corresponding author: * Tel.: +351-39-400418; fax: 351-39-829674. E-mail: antunes.cct.huc{at}sapo.pt
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Summary
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Closed mitral commissurotomy for rheumatic mitral valve stenosis was used in many tens of thousands of patients with excellent immediate results and durability, many patients having survived more than 20 years without reoperations. Gradually, this procedure was displaced by the open commissurotomy which has the advantage of direct visualisation of all valve components with immediate assessment of the anatomical and functional result. Open commissurotomy is applicable even in moderately fibrosed and/or calcified valves and in the presence of intra-atrial thrombus. Its results are well established and have not yet been bettered by less invasive procedures, such as percutaneous balloon mitral commissurotomy.
Key Words: Mitral stenosis • Open commissurotomy • Surgery
Logic, which together with good sense remains an important quality, dictates that any experienced surgeon should be able to open, undervision, a mitral valve better than a relatively soft rubber balloon can do blindly.
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Introduction
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Before open-heart surgery, closed mitral commissurotomy for rheumatic mitral valve stenosis was used in many tens of thousands of patients. The immediate results were excellent and the durability of the procedure became well established, many patients having survived more than 20 years without reoperation [1,2].
When it became possible, open commissurotomy gradually displaced the closed procedure, essentially because it is not blind, permitting the surgeon to work on all valve components with direct visualisation of the anatomical results, and confirmation of the valvular function. Besides, open commissurotomy is applicable where non-open methods are not, including moderately fibrosed and/or calcified valves, presence of intra-atrial thrombus, and permits concomitant treatment of other valve pathologies [3,4].
More recently, percutaneous balloon mitral commissurotomy was introduced [5]. Besides the obvious advantage of a less invasive procedure, the supporters of this method claim results similar or superior to those of surgery, based on a few randomised studies [6,7,8]. However, its long-term results are yet to be confirmed and it is already evident that a larger proportion of patients requires re-intervention in the medium-term [9,10].
I, therefore, remain faithful to surgery. In this work, the technique of open mitral commissurotomy is described in detail.
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Echocardiographic assessment
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Indications for surgery are patients with predominant or pure severe mitral valve stenosis (valve area <1.2 cm2), with or without symptoms. The mitral valve apparatus must be mobile with no or little fibrosis and /or calcification, as assessed by transthoracic and/or transoesophageal echocardiography (Videos 1 and 2).
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Video 1 Echocardiogram (longitudinal axis view) of a mitral valve which is amenable to open commissurotomy. There is predominant stenosis with no or little regurgitation. The leaflets are mobile, especially in the base of implantation, i.e. in the hinges, without significant calcification in the commissural areas, and with a normal or only mildly thickened subvalvular apparatus. In the longitudinal axis view, the anterior leaflet forms a typical ‘elbow’. The less fibrosis there is the greater the likelihood of the commissurotomy and of a good long-term result.
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Video 2 Echocardiogram (4-chamber view) of the same patient as in Video 1.
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Valves with mild to moderate fibrosis and/or calcification, which are not amenable to balloon commissurotomy, are not a contraindication to surgical commissurotomy (Photo 1). Under these circumstances, preservation of the valve depends on the experience of the surgeon and on the need to avoid valve replacement dictated by the characteristics of the patient with regards to his or her compliance to anticoagulation necessary after mechanical valve replacement or whose age contraindicates the use of a bioprosthesis.
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Photo 1 Transthoracic echocardiogram of a patient with severe mitral stenosis. The valve is moderately fibrosed but mobility of the leaflets at ‘hinge’ is still adequate. The valve was successfully treated by commissurotomy.
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Surgical technique
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A median sternotomy is generally used, but a right antero-lateral thoracotomy through a submammary incision is an excellent optional approach for mitral commissurotomy and may be preferred for cosmetic reasons. If a previous procedure, such as closed commissurotomy, had been performed, the pericardial adhesions are dissected. The procedure is performed under cardiopulmonary bypass, conducted as usual for other types of open heart surgery, aortic cross-clamping and perfusion of cardioplegia in the aortic root. Access to the mitral valve is usually made through the classical left atriotomy, just behind the right interatrial grove, previously dissected (Video 3).
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Video 3 Access to the mitral valve through the classical left atriotomy. A Cooley retractor is used for exposure of the valve, but special self-retaining retractors (Carpentier, Cosgrove, etc) have been developed and are used by many surgeons.
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Alternative entries to the left atrium, such as the superior and the transeptal approaches, have been used by many surgeons and give a good, unobstructed view of the mitral valve.
The anatomical characteristics of the valve are analysed to confirm pre-operative echocardiographic assessment. The subvalvar apparatus is often accessible only after commissurotomy (Video 4 and Schematic 1).
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Video 4 The anatomical characteristics of the valve are analysed to confirm pre-operative echocardiographic assessment. Nerve hooks are utilised to retract the edges of the leaflets. By pulling up both leaflets simultaneously, it is possible to demonstrate the line of fusion through which the commissural incision is to be made. Retraction also facilitates analysis of the subvalvular apparatus, as the incision progresses.
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Schematic 1 Technique of commissural incision (al = anterior leaflet; an = annulus; pl = posterior leaflet).
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If there is localised calcification of the commissures, debridement with a rongeur is carefully performed first, avoiding injury of the leaflets (Photo 2). We have successfully treated quite heavily calcified commissures with excellent results.
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Photo 2 Moderately calcified mitral valve successfully subjected to open commissurotomy, after removal of the calcium with a rongeur.
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The anterolateral commissurotomy is then initiated (Videos 5,6,7).
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Video 5 The incision is commenced at the central orifice and progresses towards the annulus. Small strokes of the scalpel are made, slowly advancing though the fusion line between the sometimes also fused attachments of the chordae tendineae. To facilitate the incision, the surgeon retracts the posterior leaflet and the assistant pulls on the anterior leaflet, with nerve hooks. The anterior commissural area is treated first. An angled-handle scalpel is used in this commissure because the blade becomes better oriented with the incision line and the chordae tendineae.
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Video 6 As the incision progresses, the nerve hooks are moved progressively towards the commissure, to facilitate exposure. The incision stops at approximately 2–3 mm from the annulus.
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Video 7 Often, the commissural chordae are thickened and shortened and the papillary muscle may even come right to the leaflet. When this happens, the head of the muscle is incised longitudinally to permit a wide separation of the leaflets.
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Often, the commissural chordae are thickened and shortened and the papillary muscle may even come right to the leaflet. When this happens, the head of the muscle is incised longitudinally to permit a wide separation of the leaflets (Schematic 2).
Once the anterior commissure has been treated, attention is directed to the posterior commissure, which is treated in a similar fashion (Videos 8,9,10).
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Video 8 For the posterior commissure a straight-handle scalpel is preferred. The orientation of the incision line is adjusted by traction of the free edges of the leaflets with the nerve hooks.
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Video 9 As the incision progresses, the surgeon observes the position of the insertions of the free-edge chordae tendineae. If lesion of these structures happens, they can be re-sutured to the leaflet or an artificial chorda may be created of PTFE.
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Video 10 When the incisions have been completed, a clear picture of the valve orifice emerges and the subvalvular area is assessed. Valve areas in excess of 3.0 cm2 have been regularly obtained, which are far greater than those reported after percutaneous balloon commissurotomy.
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Occasionally, resection of thickened chordae inserted in the ventricular surface or base of the posterior leaflet helps mobilisation of the leaflet (Photo 3). Each chorda is individualised, and held and retracted with a fine arterial forceps, and then ‘shaved’ off the surface of the leaflet. Thickened/fused free-edge chordae may be fenestrated to facilitate cusp mobility and circulation of blood through valve orifice (Schematic 3).
One of the advantages of the open commissurotomy is the possibility of immediate assessment of the valve anatomy and function. This is usually done by pressurising the left ventricle with saline injected through the mitral valve with a bulb syringe (Video 11).
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Video 11 The valve is tested by injecting cold saline into the LV either through the valve with a bulb syringe or, as we prefer, through an apical LV vent connected to the cardioplegic line, pumped by the roller pump. A fine central jet of regurgitation, resulting from orificial fibrosis, is usually present but of little haemodynamic and clinical significance. Commissural jets of regurgitation are indicative of an ill placed commissurotomy which may require correction.
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Often, the posterior portion of the annulus is enlarged and displaced posteriorly by traction of the posterior wall of the left atrium, especially when this cavity is significantly enlarged. Significant regurgitation occurs during testing (Video 12).
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Video 12 By applying anterior traction through a suture placed in the mid-portion of the posterior annulus the valve is rendered competent.
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To correct or to prevent this, we have recently used a posterior annuloplasty of the Paneth/Burr type, almost routinely (Videos 13,14,15).
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Video 13 Method of posterior annuloplasty. A double suture of 3/0 polyester, anchored to a small Teflon felt pledget, is commenced in the mid portion of the annulus and continues with small bites until the fibrous trigone is reached. The needle bites the annulus 1–2 mm behind the hinging line of the leaflet.
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Video 14 To obtain a regular and smooth plication, the bites in the second row of the suture intercalate those of the first row. The two ends of the suture are tied in the commissure over another small pledget.
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Video 15 The degree of plication is just enough to obtain apposition of the leaflets without significant stenosis. For the medial portion of the annulus, I find it technically easier to start the suture at the posteromedial commissure.
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The valve is tested again to confirm competence (Video 16). Generally, we confirm competence by pumping the saline through an apical LV cannula connected to a pumphead of the cardiopulmonary bypass machine (Schematic 4), which is thereafter used as an LV vent.
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Video 16 Repeat test of the valve confirms competence. During testing, the aortic root must be vented to minimise the risk of air embolism to the coronary arteries.
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Schematic 4 Method of testing by pumping saline through an apical LV vent cannula. Air is allowed to escape through an aortic root vent.
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Results and discussion
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From 1988 to date, we have used this technique in more than 1,200 patients. In a previously published work [11], we have described a group of 100 patients with pure pliable mitral valve stenosis, subjected to open mitral commissurotomy from 1998 through 1991. They represented 42% of the 240 patients with pure or predominant mitral valve stenosis subjected to open mitral commissurotomy during the same period. They were selected for this study by a cardiologist, upon reviewing preoperative echocardiograms (Wilkins echocardiographic score  10). These characteristics matched the contemporary most commonly accepted selection criteria for percutaneous balloon commissurotomy. The selection was blind with regards to the results of the commissurotomy. Mean postoperative mitral valve areas was 2.88±0.49 cm2 (mean preoperative valve area, 0.99 cm2). Valve areas in excess of 2.0 cm2 were obtained in all cases and 37% of the patients had a post-commissurotomy area  3 cm2. This is far in excess of values described after balloon commissurotomy. A minimum follow-up of 10 years was achieved in all patients. Ten-year actuarial survival was 96% and freedom from re-operation for mitral valve disease was 98% (Graph 1). Mean mitral valve area at the end of follow-up was 2.37 cm2 (Graph 2).
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Graph 2 Actuarial survival and freedom from reoperation and from valve-related complications in patients subjected to open mitral commissurotomy.
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In my experience, as in those of other authors [12,13,14,15], the results of open mitral commissurotomy are superior to those of valve replacement.
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References
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- John S, Bashi VV, Jairaj PS, Muralidharan S, Ravikumar E, Rajarajeswari T, Krishnaswami S, Sukumar IP, Rao PS. Closed mitral valvotomy: early results and long term follow-up of 3724 consecutive patients. Circulation 1983;68:891–896.[Abstract/Free Full Text]
- Toumbouras M, Panagopoulos F, Papakonstantinou C, Bougioukas G, Rammos K, Sbarounis CN, Lazarides DP. Long-term surgical outcome of closed mitral commissurotomy. J Heart Valve Dis 1995;4:247–250.[Medline]
- Frater RW. Balloon vs. surgical commissurotomy. Editorial. J Heart Valve Dis 1995;4:444–445.[Medline]
- Detter C, Fischlein T, Feldmeier C, Nollert G, Reichenspurner H, Reichart B. Mitral commissurotomy, a technique outdated? Long-term follow-up over a period of 35 years. Ann Thorac Surg 1999;68:2112–2118.[Abstract/Free Full Text]
- Inoue K, Owaki T, Nakamura F, Miyamoto N. Clinical applications of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 1984;87:394–402.[Abstract]
- Patel JJ, Shama D, Mitha AS, Blyth D, Hassen F, Le Roux BT, Chetty S. Balloon valvuloplasty versus closed commissurotomy for pliable mitral stenosis: a prospective hemodynamic study. J Am Coll Cardiol 1991;18:1318–1322.[Abstract]
- Reyes VP, Raju BS, Wynne J, Stephenson LW, Raju R, Fromm BS, Rajagopal P, Mehta P, Singh S, Rao DP, Satyanarayama PV, Turi ZG. Percutaneous balloon valvuloplasty compared with open surgical commissurotomy for mitral stenosis. N Engl J Med 1994;331:961–967.[Abstract/Free Full Text]
- Ben Farhat M, Ayari M, Maatouk F, Betbout F, Gamra H, Jarra M, Tiss M, Hammami S, Thaalbi R, Addad F. Percutaneous balloon versus surgical closed and open mitral commissurotomy: seven-year follow-up results of a randomized trial. Circulation 1998;97:245–250.[Abstract/Free Full Text]
- Palacios IF, Tuzcu ME, Weyman AE, Newell JB, Block PC. Clinical follow-up of patients undergoing percutaneous mitral balloon valvotomy. Circulation 1995;91:671–676.[Abstract/Free Full Text]
- Iung B, Cormier B, Ducimetiere P, Porte JM, Nallet O, Michel PL, Acar J, Vahanian A. Immediate results of percutaneous mitral commissurotomy. A predictive model on a series of 1514 patients. Circulation 1996;94:2124–2130.[Abstract/Free Full Text]
- Antunes MJ, Vieira JH, Oliveira JF. Open mitral commissurotomy: the golden standard. J Heart Valve Dis 2000;9:472–477.[Medline]
- Glower DD, Landolfo KP, Davis RD, Cen YY, Harrison JK, Bashore TM, Lowe JE, Wolfe WG. Comparison of open mitral commissurotomy with mitral valve replacement with or without chordal preservation in patients with mitral stenosis. Circulation 1998;98(19 Suppl):II120–123.
- Cotrufo M, Renzulli A, Vitale N, Nappi G, De Feo M, Ismeno G, Di Benedetto B. Long-term follow-up of open commissurotomy versus bileaflet valve replacement for rheumatic mitral stenosis. Eur J Cardiothorac Surg 1997;12:335–339; discussion 339–340.[Abstract]
- Souza LR, Pomerantzeff PMA, Brandão CMA, Cardoso LF, Carrillo LRV, Moreira LFP, Grinberg M, Oliveira SA. Late evolution of mitral commissurotomy in patients with low echocardiographic score. Eur J Cardiothorac Surg 2004;26:640–645.[Abstract/Free Full Text]
- Choudhary SK, Dhareshwar J, Govil A, Airan B, Kumar AS. Open mitral commissurotomy in the current era: indications, technique, and results. Ann Thorac Surg 2003;75:41–46.[Abstract/Free Full Text]
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Summary
Introduction
