European Journal of Cardiovascular Medicine

Giant left atrium (LA) was first described by Hewitt in 1849.1 It is a rare disease with frequency of 0.3-10%, which usually develops secondary to rheumatic mitral valve disease. Piccoli et al2 defined giant left atrium as a cardiothoracic ratio >0.7 in combination with transthoracic echocardiographic antero-posterior size of left atrium of >8cm. Oh et al3 recommended a arbitrarily defined cut-off value: more than 6.5 cm. Hurst4 defined gigantic left atrium as ``that touches right lateral wall of chest``.

Giant LA or atriomegaly is a result of longstanding pressure or volume overload of cardiac chamber, and most frequently is due to mitral regurgitation.5 For the diagnosis of a ``giant left atrium`` we accept antero-posterior size of LA >8 cm measured from parasternal long-axis view on transthoracic echocardiography.6 This condition has significant hemodynamic effects and requires specific treatment. Many authors proved, that correction of atriomegaly positively influences early and late postoperative periods, and prognosis and survival of such patients are improved.7,8

In some instances, the treatment for GLA requires a surgical-based approach. Apostolakis and Shuhaiber9 established the following conditions for potential candidates for this surgical intervention: (1) presence of intracardiac or extracardiac compressive symptoms from neighboring organs; (2) presence of thrombus and a history of thromboembolic events; and (3) to restore sinus rhythm (SR) in patients with AF, associated or not with the ablation process.9 Complex atrial surgery merits close surveillance of outcomes in the short- and long term; during this follow-up, monitoring major adverse valve-related events (MAVRE) and echocardiographic evaluation is crucial.10 Currently there is no consensus regarding the management of GLA during mitral valve surgery. Most surgeons fix the mitral valve and do little to large sized left atrium. Others occlude the left atrial appendage. Most of surgeons think that successful mitral valve surgery alone will result in the eventual remodelling of the left atrium and size reduction.9

The enlarged left atrium was found to be a risk factor for early mortality and postoperative higher thromboembolic events, but its management remains controversial.

There are many surgical techniques has been described involving wide range of complications i.e.  long duration of surgery, postoperative bleeding, low cardiac output, thromboembolic events, steep learning curve and unclear surgical efficacy raise many questions about the optimal approach to LA reduction.

The aim of the present study was to assess modified technique for large left atrial reduction in valvular heart surgery.

The present study was conducted in the Department of cardiothoracic and vascular surgery, LPS Institute of cardiology, GSVM Medical college, Kanpur from January 2017 to December 2018 A total of 36 cases in MVR and 24 cases in DVR were included in the study.

Inclusion criteria

Patient undergoing valvular heart surgery with left atrial size more than 65mm on 2D echocardiography.

Exclusion criteria

Coronary artery disease associated with valvular heart disease were not included.

Modified large left atrial reduction technique¹¹

Concept of the less-invasive volume reduction technique by means of left atrial plication.

1. Areas for left atrial volume reduction:
2. main area, the redundant left atrial wall between the mitral annulus and the left pulmonary veins.
3. additional area, the left atrial wall along the right-sided left atriotomy.
4. Plication of the left atrium. The redundant left atrial area was not excised but plicated toward the outside of the left atrial cavity (anatomic isolation).
5. Left atrial appendage plication.
6. Superior surface, area between aorta and right atrium.

LA, Left atrium; LV, left ventricle; PV, pulmonary vein; VR, volume reduction

STATISTICAL ANALYSIS

The results are presented in frequencies, percentages and mean±SD. The Chi-square test was used to compare categorical variables. The Unpaired t-test was used to compare continuous variables between the groups. The Paired t-test was used to compare the change in continuous variables from pre to post-operative within the group. The p-value<0.05 was considered significant. All the analysis was carried out on SPSS 16.0 version (Chicago, Inc., USA).

Table 1: Distribution of age between the groups

The age of patients of MVR and DVR was 33.42±6.86 and 33.38±5.50 years respectively. There was no significant (p>0.05) difference in the age between the groups showing the comparability of the groups in terms of age.

Table 2: Distribution of gender between the groups

More than half of MVR (58.3%) and 12.5% of DVR were males.  There was no significant (p>0.05) difference in the gender between the groups showing the comparability of the groups in terms of gender.

Table 3: Comparison of LA size between the groups

LA size was insignificantly (p>0.05) lower in patients of MVR than DVR at both pre and post-operative. The decrease in LA size from pre to post-operative was higher in MVR (2.81±0.38) than DVR (2.68±0.44). However, the decrease was significant (p=0.0001) in both the groups.

Table 4: Comparison of duration of surgery between the groups

Both Aortic cross clamp time and CPB time were significantly (p=0.0001) lower in patients of MVR than DVR.

Table 5: Comparison of post-operative AF between the groups

The post-operative AF was present among 58.3% patients of MVR and among 87.5% patients of DVR. However, there was no significant (p>0.05) association of post-operative AF with groups.

Table 6: Comparison of thromboembolic complications, post-operative low cardiac output and Post-operative respiratory failure between the groups

CVA was present in 8.3% patients of MVR and 25% patients of DVR. Peripheral embolism was present in 8.3% patients of MVR and was nil in patients of DVR. However, there was no significant (p>0.05) association of thromboembolic complications with groups. Post-operative low cardiac output was present in 16.7% patients of MVR and in 25% patients of DVR. However, there was no significant (p>0.05) association of post-operative low cardiac output with groups. Post-operative respiratory failure was present in 16.7% patients of MVR and in 25% patients of DVR. However, there was no significant (p>0.05) association of post-operative respiratory failure with groups.

Table 7: Comparison of post-operative bleeding re-exploration, post-operative bleeding- Blood transfusion (no. of units), Post-operative pacemaker implantation and mortality between the groups

Post-operative re-exploration was present in 16.7% patients of MVR and in 25% patients of DVR. However, there was no significant (p>0.05) association of post-operative re-exploration with groups. Two units of blood were transfused among more than half of patients in both MVR (58.3%) and DVR (62.5%). However, there was no significant (p>0.05) association of post-operative blood transfusion with groups. There was no post-operative pacemaker implantation in patients of MVR and implanted in 12.5% patients in DVR.  However, there was no significant (p>0.05) association of post-operative pacemaker implantation with groups. The mortality was in 16.7% patients of MVR and in 25% patients of DVR.  However, there was no significant (p>0.05) association of mortality with groups.

Table 9: Comparison of relief of compressive symptoms between the groups

Dysphagia was in 58.3% patients of MVR and in 62.5% patients of DVR.  Hoarseness of voice was nil in patients of MVR and was present in 12.5% patients of DVR. However, there was no significant (p>0.05) association of relief of compressive symptoms with groups.

Rheumatic heart disease (RHD) continues to be a common health problem in the developing world, causing morbidity and mortality among both children and adults. The occurrence of large LA is higher than the 0.3% as reported in the literature.12 The exact aetiology of giant left atrium (GLA) remains unknown, but a strong association occurs with chronic rheumatic mitral valve disease. Other conditions such as left ventricular failure, chronic atrial fibrillation, and left to right shunts such as patent ductus arteriosus and ventricular septal defects can also lead to left atrial enlargement, but thus is rare. The giant left atrium is a frequent finding with rheumatic heart disease. The mechanism of large LA remains unknown but is possibly related to inherent weakening of the atrial wall tissue.9

Clinical relevance of this is that the recovery of LA global function can augment LV filing and LV stroke volume. The relative contribution of LA functions becomes more dominant in the setting of high risk patients with LV dysfunction.13 In addition, LA volume reduction may contribute to the prevention of stroke or thromboembolism by increasing the blood flow velocity in the left atrium. These contributions may improve the morbidity and mortality of high- risk patients both early and late after the surgery.14 The cause of deaths were right heart failure, biventricular failure, respiratory failure, and brain haemorrhage. With respect to rates of early mortality and morbidity, there were no significant differences.

The classic plication16 technique involves occluding the left atrial appendage and plicating just the inferior wall of the left atrium. This technique results in a modest left atrial volume reduction and may leave an uneven and potentially thrombogenic surface within the left atrium. Partial plication or resection15,16 of both inferior and superior atrial walls is a more extensive reduction, which combines both superior and transseptal approaches and the posterior-inferior wall and roof of the left atrium. However, it may result in an increased risk of bleeding and conduction abnormalities inherent to the transseptal exposure.16 The partial heart auto transplantation16,17 technique provides the most extensive reduction and excellent exposure of the mitral valve; however a major disadvantage includes the extensive additional suture lines in non diseased anatomic structures (inferior vena cava, pulmonary artery, aorta) and prolonged cardiopulmonary bypass times.

The “spiral” technique16 described by Sugiki and colleagues involves a combined transseptal approach that results in an extensive resection extending from the atrial septum to the right lateral wall of the left atrium through the atrial roof, and lateral, posterior, and inferior walls of the left atrium. However a potential disadvantage of this technique is a risk of bleeding along the extensive suture lines and possible distortion of right atrial anatomy. Advantages of our described technique include avoidance of the right atrial incisions, complete exclusion of the left atrial appendage, aggressive left atrial reduction with a near circumferential resection pattern, relative simplicity, and avoidance of extensive suture lines. This novel technique achieved a 50% decrease in left atrial size, produced no significant postoperative complications, did not significantly increase operative time, and resulted in complete relief of compressive symptoms.16 Hypothetically, this patient may also experience a reduced stroke risk with reduced static blood flow in the left atrium secondary to the left atrial remodelling and complete left atrial appendage exclusion. Ongoing follow-up will be required to assess any long-term effects.16 Aggressive volume reduction procedures with the cut-and-sew technique further extend cardiac ischemic time, affect left ventricular function, increase postoperative bleeding, and might increase perioperative mortality and morbidity.18

To solve these problems, we have established the no bleeding volume reduction technique by means of LA plication. The major advantages of our technique is that it drastically reduces the cross clamp time and the risk of bleeding.

LA reduction surgery not only facilitated sinus rhythm recovery but also helped restore LA mechanical functions and facilitated LA reverse remoulding even in patients with long standing AF and LA enlargement. Moreover, if the associated mitral procedure of choice is valvuloplasty or the implantation of a mitral biological prosthesis, it will be possible to achieve the end point: to maintain the patient free of anticoagulant use.

Further study with large number of patient and longer follow up period especially in a prospective and randomized fashion, is warranted.

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8.       Beppu S, Kawazoe K, Nimura Y, Nagata S, Park YD, Sakakibara H, Fujita T. Echocardiographic study of abnormal position and motion of the posterobasal wall of the left ventricle in cases of giant left atrium. The American Journal of Cardiology. 1982 Feb 1;49(2):467-72.

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11.    Marui A, Nishina T, Tambara K, Saji Y, Shimamoto T, Nishioka M, Ikeda T, Komeda M. A novel atrial volume reduction technique to enhance the Cox maze procedure: initial results. The Journal of Thoracic and Cardiovascular Surgery. 2006 Nov 1;132(5):1047-53.

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13.    Marui A, Saji Y, Nishina T, Tadamura E, Kanao S, Shimamoto T, Sasahashi N, Ikeda T, Komeda M. Impact of left atrial volume reduction concomitant with atrial fibrillation surgery on left atrial geometry and mechanical function. The Journal of Thoracic and Cardiovascular Surgery. 2008 Jun 1;135(6):1297-305.

14.    García-Villarreal OA, Gouveia AB, González R, Argüero R. Left atrial reduction. A new concept in surgery for chronic atrial fibrillation. Revista Espanola de Cardiologia. 2002 May 1;55(5):499-504.

15.    Isomura T, Hisatomi K, Hirano A, Maruyama H, Kosuga K, Ohishi K. Left atrial plication and mitral valve replacement for giant left atrium accompanying mitral lesion. Journal of cardiac surgery. 1993 May;8(3):365-70.

16.    Adams C, Busato GM, Chu MW. Left atrial reduction plasty: a novel technique. The Annals of Thoracic Surgery. 2012 Mar 1;93(3):e77-9.

17.    Lessana A, Scorsin M, Scheublé C, Raffoul R, Rescigno G. Effective reduction of a giant left atrium by partial autotransplantation. The Annals of thoracic surgery. 1999 Apr 1;67(4):1164-5.

18.    Marui A, Nishina T, Tambara K, Saji Y, Shimamoto T, Nishioka M, Ikeda T, Komeda M. A novel atrial volume reduction technique to enhance the Cox maze procedure: initial results. The Journal of Thoracic and Cardiovascular Surgery. 2006 Nov 1;132(5):1047-53.