Tex Heart Inst J. 2006; 33(1): 51–53.

Large Left Atrial Myxoma with Severe Mitral Regurgitation
The Inverted T-Shaped Biatrial Incision Revisited

Giuseppe Davoli, MD, Luigi Muzzi, MD, Gianluca Lucchese, MD, Nicola Uricchio, MD, and Mario Chiavarelli, MD

Department of Cardiothoracic Surgery, University of Siena, Italy

Abstract

Cardiac myxomas are primary cardiac tumors. In some cases of atrial myxoma, the standard left atriotomy alone does not enable safe tumor resection and easy access to the mitral valve. We report the cases of 2 patients with huge left atrial myxomas associated with severe mitral valve regurgitation who underwent an inverted T-shaped biatrial incision for tumor excision and mitral repair. This approach reduces tumor fragmentation and permits good mitral valve exposure.

Keywords: Heart Atria, Heart Neoplasms/Surgery, Mitral Valve/Surgery, Myxoma/Surgery

Cardiac myxomas are primary cardiac tumors. In some cases of atrial myxoma, the standard left atriotomy alone does not enable safe tumor resection and easy access to the mitral valve. We report the cases of 2 patients with huge left atrial myxomas associated with severe mitral valve regurgitation who underwent an inverted T-shaped biatrial incision for tumor excision and mitral repair.

Case Reports

Patient
In June 2004, a 37-year-old woman was admitted to our emergency room with symptoms of congestive heart failure. Her recent history included episodes of supraventricular tachycardia and atrial fibrillation. Transthoracic 2-dimensional echocardiography showed enlarged left cardiac chambers: the left ventricular diastolic diameter was 68 mm, and the transverse left atrial diameter was 56 mm. The left ventricular function was depressed, with a 0.25 ejection fraction. A huge left atrial mass was attached to the atrial septum by means of a broad pedicle (Fig. 1). The mitral valve leaflets appeared thin, and there was mild mitral regurgitation. The tumor, which filled most of the left ventricular cavity, had a 103-mm longitudinal diameter, as measured intraoperatively by transesophageal echocardiography.

Cardiopulmonary bypass was established by bicaval cannulation, and cardioplegic arrest was induced by antegrade perfusion of cold blood. We made a horizontal incision of the left atrium in front of the right superior pulmonary vein; then we made a 2nd vertical incision into the right atrium, starting at a point 3 to 4 cm lateral to the atrioventricular groove toward the sulcus terminalis and connecting to the 1st incision on the left atrium. A coronary sinus catheter was inserted for retrograde cardioplegia. We observed that the tumor had its origin near the fossa ovalis. The incision was extended into the interatrial septum, to a point about 5 mm from the pedicle (Fig. 2A). The tumor was excised, along with a wide margin of tissue around its base, and was removed intact through the opening (Figs. 2B and 3). All 4 chambers were inspected for possible multicentric tumors. The mitral valve leaflets and subvalvular apparatus appeared to be normal, but severe central mitral regurgitation was demonstrated by saline injection. Therefore, a 30-mm mitral annuloplasty Carpentier-Edwards Physio ring (Edwards Lifesciences; Irvine, Calif) was inserted, and the atrial septal defect that we had created was patched with glutaraldehyde-treated autologous pericardium (Fig. 2C). Then the free edge of the left atriotomy was sewn to the patch so that the suture line corresponded with the interatrial groove, and the aortic clamp was removed. The right atriotomy was closed at the beating heart with running sutures, and cardiopulmonary bypass was easily discontinued (Fig. 2D). Postoperative transesophageal echocardiography demonstrated trivial mitral regurgitation and did not show evidence of residual tumor or atrial shunting.

The patient was discharged on the 11th postoperative day. At the 3-month follow-up, echocardiography showed a 59-mm left ventricular diameter at diastole and 0.45 ejection fraction, with a competent mitral valve.

Patient 2
In January 2005, a 62-year-old woman was admitted for resection of a large left atrial myxoma. Her clinical history revealed only minor symptoms associated with persistent atrial fibrillation. Transthoracic echocardiography showed a 42-mm left atrial diameter, normal left ventricular size with 0.60 ejection fraction, apparently trivial mitral regurgitation, and a huge mass in the left atrium that was attached to the atrial septum very close to the posteromedial mitral commissure. The mass appeared to prolapse significantly into the left ventricle during diastole.

The same approach (described for Patient 1) was used to excise the tumor, which was 60 x30 mm (Fig. 4). The mitral leaflets were very thick, and severe mitral regurgitation was demonstrated at the level of the posteromedial commissure. We used Alfieri's paracommissural edge-to-edge technique to obliterate leaflets A3 and P3, without positioning a ring. Microwave ablation was used to treat the atrial fibrillation. Transesophageal echocardiography showed no mitral regurgitation and a calculated mitral valve area of 3.5 cm2.

The patient's postoperative course was uneventful. Two months later, she was in sinus rhythm and had a competent mitral valve. At the 6-month follow-up, echocardiography showed normal left ventricular dimensions and systolic function. No mitral regurgitation was observed, and the patient was in good clinical condition, with only 1 documented episode of paroxysmal atrial fibrillation.

In both of these patients, histologic examination confirmed the diagnosis of myxoma.

Discussion

Left atrial access alone does not enable complete heart inspection, requires significant tumor manipulation in the event of a large mass, and may not permit radical resection. Similarly, a right atriotomy with septal incision may not accommodate removal of a large tumor mass without fragmentation. Kabbani and Coole 1 excised a left atrial myxoma using a biatrial approach in 1973, and Jones and colleagues 2 described many advantages associated with this technique. The inverted T-shaped incision was first described by Campanella and co-authors 3 to expose the mitral valve in a small left atrium, and then it was used by Morishita and associates 4 in resecting a large left atrial myxoma. Optimal exposure enables radical excision of the tumor and reduces its manipulation, and at the same time permits exploration of all 4 chambers. Potential complications associated with the biatrial approach include supraventricular arrhythmias, conduction disturbances, and postoperative left-to-right shunting. The superior septal approach can in most cases provide good exposure of the left atrium and the mitral valve, but it has a possible adverse effect on sinus node function, due to its extensive horizontal right atrial incision.

Whether the surgeon is confronting a huge myxoma or secondary mitral valve damage, an extended incision gives better exposure. When a large tumor mass grows from the atrial septum into the left ventricle, it can compromise mitral valve competence even if that is not obvious preoperatively. Mitral regurgitation can be a consequence of ventricular and annular dilatation or of direct leaflet damage. Consequently, severe mitral regurgitation becomes evident after tumor resection.

Large left atrial myxomas are effectively approached via the T-shaped inverted biatrial incision, which enables controlled tumor removal, excellent mitral valve exposure, and 4-chamber inspection, while reducing the risk of sinus node damage that accompanies a vertical right atrial incision.

Footnotes

Address for reprints: Luigi Muzzi, MD, Department of Cardiovascular Surgery, University of Siena, Policlinico "S. Maria alle Scotte." Viale Bracci no. 1, 53100 Siena, Italy

E-mail: luigimuzzi@hotmail.com

References
1.
Kabbani SS, Cooley DA. Atrial myxoma. Surgical considerations. J Thorac Cardiovasc Surg 1973;65:731 --7. [PubMed].
2.
Jones DR, Warden HE, Murray GF, Hill RC, Graeber GM, Cruzzavala JL, et al. Biatrial approach to cardiac myxomas: a 30-year clinical experience. Ann Thorac Surg 1995;59: 851 --6. [PubMed] [Full Text].
3.
Campanella C, Cameron E, Feilberg VL. Mitral prosthetic replacement in small left atria. Ann Thorac Surg 1990;50: 836 --7. [PubMed].
4.
Morishita K, Fukada J, Abe T. Inverted T-shaped biatral incision for large left atrial myxoma. J Card Surg 1997;12: 112 --5. [PubMed].
Figures and Tables
figure 12FF1
Fig. 1 Patient 1: Echocardiographic demonstration of the huge atrial myxoma.
figure 12FF2
Fig. 2 A) Inverted T-shaped biatrial approach. B) Mitral view after tumor resection. C) Patch closure of the atrial septal defect. D) Closure of the T-inverted biatrial incision.
figure 12FF3
Fig. 3 Patient 1: The large atrial myxoma after excision.
figure 12FF4
Fig. 4 Patient 2: This view shows the wide margin of tissue excised around the base.