Departments of Cardiac Surgery, Radiology, and Cardiology, Montreal Heart Institute, University of Montreal, Montreal, Quebec,Canada
We describe a simple and reproducible technique per-mitting both effective left atrial reduction plasty and safemitral annulus reconstruction, using a patch of leftatrium tissue. In a 64-year-old patient undergoing redomitral valve replacement for mechanical prosthesis disin-
sertion, a giant left atrium and extensive calcification of
Surgery, Montreal Heart Institute, 5000 Bélanger St, Montréal H1T 1C8,Quebec, Canada; e-mail: [email protected].
the mitral annulus were noted. This technique permitteda safe mechanical mitral prosthesis re-replacement and asignificant reduction of left atrial volume by 70%.
In rare instances, chronic mitral valve disease is asso-ciated with a giant left atrium, which may result in
respiratory dysfunction due to bronchial compression,hemodynamic disturbance produced by compression ofthe left ventricle, and a thromboembolic risk despiteanticoagulant therapy. Left atrium size is a major predic-tive factor of death, thus reduction of its volume couldimpact patients’ prognosis [1].
Extensive calcification of the mitral valve annulus isoften observed in this context of giant left atrium andrepresents an added technical difficulty for implantingprosthetic valves.
We describe a technique permitting both effectiveleft atrial reduction plasty and safe mitral annulusreconstruction.
Technique
A 64-year old man presented with a 6-month history ofNew York Heart Association class III dyspnea. His pastmedical history was significant for mechanical mitralreplacement with a Lillehei-Kaster tilting-disc prosthesisdue to rheumatic valve disease at age 26 and long-standing persistent atrial fibrillation.
Transthoracic echocardiography revealed severe mitralparavalvular leak, ejection fraction of 0.65 and dilated leftatrium. Computed tomography confirmed a giant leftatrium without endocavitary thrombus and nearly totaloccupation of the middle-lower portion of the righthemithorax with compression of the right lung. Left atrialdimensions were 18.5 � 16 � 14 cm (Fig 1 A and B) withan estimated volume of 2,160 mL. The decision wastherefore made to replace the prosthesis and perform aleft atrial reduction.
Accepted for publication Oct 15, 2012.
Address correspondence to Dr El-Hamamsy, Department of Cardiac
After median sternotomy, the heart and the caval veinsin particular were cleared from adhesions and cardiopul-monary bypass was initiated with aortic and bicavalcannulation. The left atrium was circumferentially dis-sected from pulmonary veins to the mitral valve. TheSondergaard plane was then isolated; a wide left atri-otomy incision revealed a redundant left atrium rollingon itself. The left atrial appendage and the posterior leftatrial wall were prolapsing into the luminal area of theleft atrium. The mechanical mitral valve was foundextensively detached on its left lateral portion (7 o’clockto 10 o’clock). After prosthesis removal, the mitral annu-lus appeared densely calcified, particularly in its poste-rior part. A large rectangular segment of left atrium wasremoved between the right pulmonary veins and theinteratrial septum and used for mitral annulus recon-struction. A circumferential left atrial reduction was per-formed internally by plicating the left atrial wall fromnear the origin of the left superior pulmonary vein,clockwise toward and including the entire left atrialappendage, continuing posteriorly to the circumflex ar-tery down to and along the posterior mitral annulus (Fig2A;B), with a running 5-0 polypropylene suture. Partialplication of the inferior atrial wall was associated toresection of the right lateral wall and resulted in exten-sive reduction. The left atrial patch was then tailoredapproximateIy 2-cm larger than the defect in the mitralannulus (2-cm wide and 7-cm long). The circular marginof the patch was sutured to the endocardium of the leftventricle with a continuous 4-0 polypropylene suture (Fig2C). A 33-mm St Jude mechanical mitral prosthesis wasinserted (Fig 2D). The left atrial reduction plasty wascompleted on the right side by excising all redundanttissue between the right-sided pulmonary veins and theinteratrial septum, extending down below the inferiorvena cava. Cross-clamp and cardiopulmonary bypasstimes were 153 and 189 minutes, respectively.
The postoperative course was uneventful and the patient
was discharged home on postoperative day 10. Transtho-
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racic echocardiography confirmed a well-functioning pros-thetic mitral valve, trace tricuspid insufficiency, and signif-icant reduction in left atrial dimensions.
The cardiothoracic ratio on the chest roentgenogramwas markedly reduced from 90% to 67%. The chestcomputed tomography (Fig 1C) clearly demonstrates thereduced size of the left atrium (9.5 � 15 � 8 cm) with anestimated volume of 590 mL (ie, 72% reduction comparedwith preoperative).
Comment
We report a simple and effective surgical technique tocarry out at the same time the giant left atrial reductionplasty and mitral annular reconstruction. Giant leftatrium is a condition defined when the left atrial diame-ter exceeds 65 mm [2]. Giant left atrium is commonly
Fig 1. (A) Coronal CT showing preoperative the giant left atrium comatrium and the Lillehei-Kaster tilting-disc prosthesis (arrow), and (C)phy; LA � left atrium; LV � left ventricle; RA � right atrium; RV �
Fig 2. (A) Left atrial resection line and tailor-ing of the left atrial patch. (B) Left atrium re-duction plasty by plicating the inferior wall.(C) After prosthesis removal, reconstruction ofthe mitral annulus with a left atrial patch. (D)Final aspect with prosthesis in position.
associated with mitral valve regurgitation due to excessintracavitary pressure resulting in strain and dilation ofthe left atrial chamber. The enlarged left atrium leads toexpansion of left atrial volume, which in turn can exertpressure on the main bronchus, lung, and left ventriclewith corresponding cardiopulmonary dysfunction. More-over, giant left atrium increases the risk of thromboem-bolism and sudden death [1], and its existence thereforemerits careful evaluation and surgical intervention whenneeded.
Previously described techniques include partial plica-tion, patterned excisions and partial autotransplantationof the heart [3–5]. Classic plication technique involvingthe left atrial appendage and just the inferior wall of theleft atrium [3] results in a modest left atrial volumereduction and may leave a potentially thrombogenicsurface within the left atrium. Resection of both inferior
sing the liver. Axial CT showing (B) preoperative the giant leftostoperative left atrial reduction plasty (CT � computed tomogra-
t ventricle.)
presthe p
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and superior atrial walls [2, 4] results in more extensivereductions but may increase risk of bleeding and conduc-tion abnormalities, particularly if transseptal exposure isused. The partial heart autotransplantation techniquepermits the most extensive reduction and excellent ex-posure of the mitral valve but at the cost of extensiveadditional suture lines in nondiseased anatomic struc-tures (inferior vena cava, pulmonary artery, aorta) andprolonged cardiopulmonary bypass times [5]. Moreover,it is presumably associated with a significantly higheroperative risk.
Advantages of our described technique include avoid-ance of the right atrial incisions, complete occlusion ofthe left atrial appendage, avoidance of extensive suturelines with their inherent risk of bleeding and thrombo-genicity, and limiting resection to easily accessible areas.Despite its relative simplicity, left atrium plication plastyassociated to right lateral wall resection achieved a 70%decrease in left atrial volume, without significant postop-erative complications. It is advisable to perform plicationat some distance from the mitral annulus to avoid injuryto the left circumflex coronary artery. Long-term fol-low-up is nevertheless necessary to ensure the stability ofthe plication, which has been reported to dehisce in somecases.
Extensive calcification of the mitral annulus and dam-aged mitral annulus as a result of iterative mitral valvereplacements are associated with high operative mortal-ity and morbidity, such as prosthetic valve malfunctionand dehiscence [6]. Some authors reported their experi-ence with mitral valve iterative replacement and exten-sive annular calcification. Nataf and colleagues [7] se-cured a prosthetic mitral valve to the left atrial wall byexpanding its sewing cuff with a Dacron collar. Operativemortality rate was 36%, and 20% of survivors requiredreoperation because of prosthesis dehiscence].
Reconstruction of the annulus makes reoperative mi-tral valve surgery safer. David and colleagues [8] re-ported their experience with reconstruction of the mitralannulus, alternatively using fresh autologous pericar-dium, glutaraldehyde-fixed bovine pericardium and Da-cron graft. Operative mortality rate was 8.6%. However,
Dacron graft is a rigid material, difficult to use for
three-dimensional reconstruction, and autologous andbovine pericardium, although flexible and resistant ma-terials still present the main disadvantage of long-termcalcification.
Carpentier and colleagues [9] first reported their expe-rience with left atrium tissue to reconstruct damagedmitral annulus. In the “sliding atrium technique” theatrial edge was dissected free to mobilize an atrial flap,used to cover the decalcified area].
We think that patch of left atrial tissue is the mostappropriate material to reconstruct the mitral annulus,provided adequate structure and thickness (� 2 mm).Anatomically, it restores a normal continuity of the mitralendocardium, which may help in preventing tissue pro-liferation, thickening, and thrombosis. Longer follow-upis still necessary to confirm its resistance to calcificationand long-term durability.
References
1. Reed D, Abbott RD, Smucker ML, Kaul S. Prediction ofoutcome after mitral valve replacement in patients withsymptomatic mitral regurgitation. The importance of leftatrial size. Circulation 1991;84:23–34.
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3. Fujita T, Kawazoe K, Beppu S, Manabe H. Surgical treatmenton mitral valvular disease with giant left atrium: the effect ofpara-annular plication on left atrium. Jpn Circ J 1982;46:420–6.
4. Adams C, Busato GM, Chu MW. Left atrial reduction plasty:a novel technique. Ann Thorac Surg 2012;93:e77–9.
5. Lessana A, Scorsin M, Scheublé C, Raffoul R, Rescigno G.Effective reduction of a giant left atrium by partial autotrans-plantation. Ann Thorac Surg 1999;67:1164–5.
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