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© 2003 European Association of Cardio-Thoracic Surgery
Atrial versus biatrial approaches for cardiac myxomasResearch Center and Department of Surgery, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
* Corresponding author. Research Center, Montreal Heart Institute, 5000 Belanger Street East, Montreal, Quebec, H1T 1C8 Canada. Tel.: +1-514-376-3330; fax: +1-514-376-1355 Received March 7, 2003; received in revised form June 19, 2003; accepted June 21, 2003
Myxomas are the most common primary benign tumors of the heart. The objectives of this study were to review the different surgical approaches to intracardiac myxomas and to assess the long-term prognosis of these patients. We present a retrospective review of 58 intracardiac myxomas surgically removed at the Montreal Heart Institute between September 1975 and May 2002. Nineteen male and 38 female patients with a mean age of 56±13 years were operated for cardiac myxoma. Atrial and biatrial approaches were used in 41 and 59% of cases, respectively. The mean follow-up was 8.8±6.4 years. Supraventricular arrhythmias and conduction disturbances were the most frequent complications following surgery (39%). One patient died early from malignant arrhythmia and eight other patients succumbed during the follow-up period with two cardiac-related deaths from recurrent myxoma and endocarditis, respectively. The overall 10-year actuarial survival was 86±6%. The retrospective comparison of atrial versus biatrial approaches showed marginal difference in the procedural time and no significant difference in blood losses, transfusion requirements, length of stay, postoperative NYHA functional class and survival. Notwithstanding the approach performed, the surgical treatment of cardiac myxomas is associated with a low operative mortality and good long-term outcome.
Key Words: Cardiac myxoma; Outcome; Surgical approaches Myxomas are the most common primary benign tumors of the heart [1,2]. Bjessmo and Ivert [3] recently reported the Stockholm experience with cardiac myxomas in 63 patients with a 13-year median follow-up. Myxoma excision is associated with a low reported mortality and morbidity [3–13], and excellent long-term results with 20-year actuarial survival of 85–95% [3–5]. The objectives of this study were to review the different surgical approaches to intracardiac myxomas and to assess the long-term prognosis of these patients over a 25-year period.
1.1. Patients characteristics Between September 1975 and May 2002, 58 intracardiac myxomas were removed surgically at the Montreal Heart Institute. There were 19 male and 38 female patients with a mean age at operation of 56±13 years including one female patient operated twice due to recurrence. Atrial and biatrial approaches were used in 41 and 59% of patients, respectively. The biatrial approaches group included patients operated through a left+right atriotomy (LA+RA,  ), a right atriotomy+transseptal incision (RA+TS,  ) or a left+right atriotomy+transseptal incision (LA+RA+TS,  ). Criteria to select either technique were left at the surgeon's discretion. All medical records were reviewed. The late outcome and survival data were obtained through outpatient clinic visits, telephone interviews and review of government records. Clinical data were retrospectively compared for patients operated through an isolated atrial approach ( ) versus the biatrial approaches ( ) (Table 1). The two groups' characteristics were similar except for a better preoperative functional class (NYHA class III–IV: 58% for atrial versus 26% for biatrial approaches,  ) and higher rate of preoperative embolization in the biatrial approaches group (4% for atrial versus 50% for biatrial approaches,  ).
1.2. Surgical technique Bicaval cannulation and snaring for venous return was always employed with special attention to manipulation of the heart prior to aortic cross-clamping to avoid tumor fragmentation and systemic embolization. Cold hyperkalemic crystalloid cardioplegia was used initially and then changed in 1992 to blood-crystalloid (4:1) cardioplegia with mild systemic hypothermia (31 °C). Left atrial myxomas were excised through a left atrial approach in 22 patients (41%), an LA+RA in 24 (45%), an RA+TS in 4 (8%) and an LA+RA+TS in 3 (6%). Right atrial myxomas were excised through an RA approach in two patients (40%), an LA+RA in two (40%), and an RA+TS in one (20%). Atriotomy were performed to obtain a good exposure of both the tumor base and septum. With the atrial approaches, preoperative and intraoperative echographic confirmation of the absence of contralateral myxoma was obtained. With the biatrial approaches, both atria and ventricles were carefully inspected for tumor fragments or other myxomas. The objectives of the resection were complete tumor excision with removal of the attachment base to prevent recurrence, with a full thickness resection performed in 88% of the cases. Intramural resections (subendocardial) (12%) were used when a full-thickness resection would have led to disruption of structural or functional integrity. Seventeen patients (29%) had associated procedures, evenly distributed in both approach groups: six CABG, 10 mitral valve repair or replacement and one aortic valve replacement. 1.3. Statistical analysis Data are expressed as mean±SD. Proportion analysis was performed with 2 test. Analysis of survival was performed with the Kaplan–Meier method. The level of statistical significance was established at 95% ( ). The statistical analyses were performed using NCSS 2001 (NCSS Statistical Software, Kaysville, Utah).
2.1. Surgical findings The tumor was located in the left atrium in 53 patients, in the right atrium in four and had a biatrial localization in one (Table 2). There were more myxomas located on the left atrial wall/mitral valve annulus, and less on the left atrial septum in the atrial approach versus the biatrial approaches group. In one case (2%), resection of the myxoma was incomplete because of a deep extension of the left atrial tumor into the left ventricle. The myxoma was attached to the endocardial surface by a fibrous stalk in 43 patients (74%). In 79% of patients, the wide excision around the attachment base (17±10 mm) included a rim of normal interatrial septum. The interatrial septum was closed primarily (72%) or using a Dacron patch (7%), autologous (17%) or bovine pericardial patch (4%).
2.2. Pathological findings A gelatinous, friable or myxoid tumor was found in 48% of the specimens. Histologically, the tumors were composed of polygonal and stellate cells in a vascular myxoid stroma. Intratumoral hemorrhage was present in 38%, calcification in 5% and osteoid formation in 3%. In one patient who presented with tumor recurrence and extracardiac metastasis a specimen of the skin metastasis was analysed by the Armed Forces Institute of Pathology (Washington, DC), which concluded to a probable pleiomorphic sarcoma. The cardiopulmonary bypass and cross clamping times were slightly decreased for the atrial approach versus the biatrial approaches group (  and 0.04, respectively; Table 2). There were no significant differences in the blood losses, transfusion requirement, length of stay, postoperative NYHA functional class and survival. No patients returned to the operating room for bleeding. Early cardiac complications occurred in 28 patients (48%), primarily arrhythmias and conduction disturbances (39%). The prevalence of residual shunts was increased in the atrial approach compared with the biatrial approaches group (). One patient died within 30 days of the operation (operative mortality: 2%). This patient underwent intramural excision of a large left atrial wall myxoma by a left atrial approach with combined single-vessel CABG. On postoperative day (POD) 12, she went into cardiac arrest. Cardiopulmonary resuscitation was unsuccessful and the autopsy was turned down. One year after successful excision of a myxoma by a left atrial approach, one patient had a recurrent myxoma in the right atria at the junction of atrium and superior vena cava which was reoperated through an LA+RA approach. On POD 7, she presented with a superior vena cava syndrome and the cava was later reconstructed with a pericardial patch. Postoperative course was complicated by multiple organ failure and death on POD 72. 2.4. Late results and survival The mean follow-up was 8.8±6.4 years (range of 16 days to 27 years). The follow-up was complete in all patients. Echocardiography was not performed routinely at follow-up, but was obtained in 33 patients (57%) at 7±6 years postoperatively showing only one recurrence (cf. Section 2.3). Eight late deaths were encountered (14%) with only two cardiac-related deaths (Table 3). Excluding deceased patients, only five of 47 patients (11%) were in NYHA functional class III–IV postoperatively compared to 16 of 48 patients (33%) preoperatively ( ). Other late complications were present in seven patients (10%). The actuarial survival was 86±6 and 72±9% at 10 and 20 years, respectively, and was independent of the approach chosen ( ) (Fig. 1).
The major findings of this retrospective study are: (1) atrial and biatrial approaches yield similar surgical results, morbidities and mortalities; and (2) myxoma recurrence should raise the possibility of malignancy. Myxoma is the most common primary cardiac tumor of the heart, accounting for almost 50% of the benign cardiac tumors in the adult [1,2]. The combined experience of the Eisenman French Joint Study and the Broussais Hospital of 444 surgically treated cardiac myxomas was reported with an overall operative mortality of 4.3% and recurrence of 2%[6]. Others [5,7–13] have reported their surgical experience with cardiac myxoma in groups of 4–66 patients with similar results. The present study was performed to add further information concerning the results of surgical treatment according to surgical approach and the long-term prognosis of patients with myxomas. There is general agreement about the necessity to proceed to a full-thickness resection with clear margins to minimize the risk of recurrence [3–13]. Although 12% of patients underwent intramural resection, none presented recurrences at the resection site. Recurrence of a sporadic myxoma is unusual, occurring in 1–3% of cases [7,9]. Only one recurrence was observed (2%) in this series in a patient in whom the atrial approach was used initially. Both atrial resected tumors were histologically identified as benign myxoma, while the skin metastasis was identified as possible pleiomorphic sarcoma with myxoid stroma and could represent a myxoma with malignant potential ("myxoid imitator") as suggested by Attum et al. [14]. Whether the recurrence was due to incomplete removal with failure to explore both atrial cavities or represent the malignant potential of that particular myxoma is unclear. Jones et al. [8], in a review of the largest series of operative approaches to atrial myxomas, illustrated the ongoing controversy about the most appropriate surgical approach given that the atrial, LA+RA and RA+TS approaches were each used in about one-third of cases. In this report the atrial, LA+RA, RA+TS and LA+RA+TS approaches were used in 41, 45, 9 and 5% of patients, respectively, in a single center. There was no clinically significant difference between atrial and biatrial approaches for the procedural time, blood losses, transfusion requirements, length of stay, postoperative NYHA functional class and survival. The LA+RA approach is a safe and efficacious technique which allows excellent exposure, thorough inspection of all four cardiac chambers and both atrioventricular valves, optimal removal of margins, exclusion of multifocal tumors and prevention of intraoperative embolization and recurrence [8– 10]. Although the atrial approach may compromise exposure of large tumors and their attachment base in a non-dilated atrium [8,9], it is an expeditious, simple and effective technique for atrial myxomas excision [2,7,11]. Furthermore, with the advent of TEE, direct visual inspection of all four cardiac chambers may become unnecessary [7]. However, the atrial approach may overlook small tumoral implants not echographically visible. In the present report, residual shunts were more common with that approach, which could be related to an imperfect exposure and inadvertent perforation of the interatrial septum. In our experience, we favoured the biatrial approach when myxomas were attached to the interatrial septum. The principal criticism about the biatrial approaches is the high incidence of arrhythmias and conduction disturbances following resection of left sided myxomas [8,13,15]. In the present report, the incidence of significant dysrhythmias or conduction disturbances using the atrial and biatrial approaches was 46 and 35%, respectively. Atrial flutter or fibrillation occurred mostly in the atrial approach group and complete atrioventricular block occurred most often in patients operated through the biatrial approaches. However, 95% of patients were in normal sinus rhythm at discharge and only one patient required implantation of a permanent pacemaker. The pathophysiology of these arrhythmias and conduction disturbances is unclear but could be related to excessive retraction (atrial approach) or to transitory edema of the conduction system secondary to extensive incisions through the heart (biatrial approaches). Although the early mortality reported in this series is low (2%), the late mortality is higher (14%) than in previous reports. Only two deaths were cardiac-related. The decreased survival at 20 years is explained by three late deaths of unknown origin. The high prevalence of NYHA class III or IV following myxoma resection (seven patients, 14%) is unusual since all those patients except one had isolated myxoma resection and comparable operative data, but could be partly explained by the older age of those seven patients (mean 64 years). The present study has several limitations. Retrospective studies are susceptible to selection and recall bias. For instance, many surgeons think that biatrial approaches help to prevent intraoperative embolization and most patients with preoperative stroke were operated through biatrial approaches. However, considering the rarity of the disease, a prospective randomized study would be impractical. Biatrial approaches were considered as a group of three approaches (LA+RA, RA+TS, LA+RA+TS). This was done to facilitate the comparison between atrial and biatrial approaches. In conclusion, the extended follow-up of patients with intracardiac myxomas shows that surgical excision of such tumors is curative with low mortality and good long-term outcome. Transitory arrhythmias and conduction disturbances remain a significant postoperative occurrence independent of the surgical approach performed. doi:10.1016/S1569-9293(03)00135-X
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Abstract
1. Materials and methods