Graphical abstract
Keywords: Minimally invasive cardiac surgery, Cor triatriatum sinister
Highlights
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CTS is characterized by a membrane that divides the left atrium into two chambers.
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This patient also presented with mitral regurgitation.
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The authors present multimodality images and intraoperative video clips.
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In this case, repair was performed with a minimally invasive approach.
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Intraoperative echocardiography is an essential element of patient care.
Introduction
Cor triatriatum sinister (CTS) presents uncommonly in adults and is characterized by an anomalous fibromuscular membrane separating the left atrium into upper and lower chambers with a communicating orifice. The size of this orifice determines the severity of obstructive symptoms experienced, which often mimic mitral stenosis. Larger communications are often asymptomatic or become symptomatic in adulthood. Definitive management requires surgical resection, traditionally approached through median sternotomy. Minimally invasive cardiac surgery offers a number of potential benefits, including quicker recovery time, reduced hospitalization time, and more cosmetically appealing results. We present the case of a patient with CTS, atrial fibrillation, and mitral regurgitation who underwent successful minimally invasive repair through an endoscopic, right minithoracotomy approach.
Case Presentation
A 72-year-old female marathon runner presented with a 1-year history of intermittent dyspnea that occurred unpredictably both on exertion and at rest. She had a history of mitral valve prolapse with mild to moderate regurgitation and previous breast augmentation surgery. An implantable loop recorder showed episodes of paroxysmal atrial fibrillation, and repeat echocardiography ordered by her primary care physician demonstrated progression to moderate to severe mitral regurgitation, trace tricuspid insufficiency, and a tricuspid annular diameter measuring 35 mm. She was referred for possible mitral valve repair. Physical examination demonstrated a pansystolic murmur best heard over the apex of the heart and a high-pitched diastolic murmur. Respiratory examination was unremarkable. She had no ankle edema, and her jugular venous pressure was normal.
Electrocardiography in the clinic revealed sinus rhythm. Computed tomography confirmed the divisive membrane consistent with CTS in the left atrium (Figure 1) and normal pulmonary venous connections (Videos 1 and 2). Transthoracic and transesophageal echocardiography (TEE) demonstrated bileaflet prolapse of the mitral valve with severe regurgitation (Figure 2, Video 3), left atrial enlargement, and surprisingly a large membrane separating the left atrium into upper and lower chambers (Figure 3, Video 4).
Figure 1.
Computed tomography of the chest showing sagittal and coronal views of the heart, with left atrium (LA) divided into two chambers by the membrane (arrow). LV, Left ventricle; RA, right atrium; RV, right ventricle.
Figure 2.
Multiplanar reconstruction of the mitral valve shows Barlow's pathology with significant billowing or prolapse of the mitral valve.
Figure 3.
Echocardiography demonstrating the left atrium (LA) divided by the membrane (arrow). Ao, Aorta; LV, left ventricle.
At the time of operation, the patient was placed in a 20° left lateral decubitus position. Her previous inframammary crease incision was reopened, and her previous breast implant was temporarily removed. A port incision was made through the fourth intercostal space, midaxillary line, and cardiopulmonary bypass was initiated through jugular and femoral access. Intraoperative TEE again demonstrated the CTS membrane dividing the left atrium into two compartments. The proximal chamber was continuous with all four pulmonary veins, with the distal chamber containing the mitral valve. Color flow Doppler demonstrated a small calcified communication within the membrane with turbulent blood flow between the proximal and distal chambers. Three-dimensional TEE localized this communication close to the posterior wall of the left atrium (Figure 4). A transverse left atriotomy was used, and a 5-mm endoscope provided optimal exposure of the CTS membrane (Figure 5, Video 5). After complete resection of the membrane, the left atrial chamber was completely visualized, with a normal view of the pulmonary veins and mitral valve apparatus (Video 6). A left-sided cryomaze ablation was performed, and the mitral valve was repaired with a 32-mm remodeling annuloplasty ring (Figures 6 and 7). Despite mild tricuspid prolapse, the tricuspid valve was not repaired, as the patient had trace tricuspid insufficiency, a nondilated tricuspid annulus, and no symptoms of right-sided heart failure. TEE confirmed successful resection of the CTS and effective repair of the mitral valve (Video 7). After closure of the intercostal space, she underwent bilateral revision breast augmentation.
Figure 4.
Color Doppler echocardiography demonstrating flow through a fenestration (arrow) in the CTS membrane (Mn). Three-dimensional echocardiographic image demonstrating a fenestration (arrow) in the membrane. LA, Left atrium; MV, mitral valve.
Figure 5.
The membrane was visualized under direct vision with identification of the fenestration (arrow). The membrane was resected under endoscopic visualization with the mitral valve revealed behind the membrane.
Figure 6.
The repaired mitral valve with annuloplasty ring.
Figure 7.
Three-dimensional TEE shows en face view of the repaired mitral valve.
Postoperatively, the patient recovered well and was discharged home on the fourth postoperative day in normal sinus rhythm. At 1-year follow-up, she was well and without dyspnea (New York Heart Association functional class I). Electrocardiography revealed sinus rhythm. Transthoracic echocardiography showed normal atrial blood flow without obstruction or mitral insufficiency.
Discussion
Cor triatriatum occurs in <0.1% of patients with congenital heart disease.1,2 In CTS, the left atrium is typically divided into a proximal chamber (containing the pulmonary venous return) and a distal chamber (containing the atrial appendage and mitral valve). The proximal chamber communicates with the rest of the heart either through a number of fenestrations in the CTS membrane (most common) or through a number of anomalous venous connections.2 Many cases present in infancy with symptoms of congestion, but CTS with milder degrees of obstruction may go unnoticed until adulthood.1 A small fenestration in our patient allowed the passage of blood into the distal chamber. The orifice was large enough to allow reasonable compensation of the obstruction. However, as her mitral regurgitation progressed, it is likely that the regurgitant flow reduced the pressure gradient between the proximal and distal chambers and effectively reduced the driving force for flow through the fenestration. We postulated that this resulted in worsening obstruction and along with the development of paroxysmal atrial fibrillation led to the progression of symptoms in our patient.3 The concomitant presentation of CTS and Barlow's disease is a rare occurrence and has been previously suggested that the obstructive membrane in CTS may in fact mask or hide the degree of mitral regurgitation in Barlow's disease.4
Multimodal imaging, including two-dimensional and three-dimensional echocardiography and cardiac-gated computed tomography played a critical diagnostic role in our patient but also helped inform the intraoperative guidance of resection and repair.5 Preoperatively, transthoracic echocardiography and three-dimensional TEE are the mainstay of workup for patients with CTS at our center. Computed tomography was used to further delineate the left atrial anatomy, such as identification of unrecognized anomalous venous pathways, and to assess for minimally invasive approaches to repair. Intraoperatively, we rely on TEE to guide repair and provide a real-time assessment of its effectiveness. The 5-mm endoscope aids exposure and complete visualization of the anatomy that would be otherwise impossible through the port incisions. Finally, echocardiography is relied upon for follow-up during both the immediate and long-term postoperative period.
Conclusions
Minimally invasive approaches to repair of cor triatriatum are effective and beneficial in appropriate patients. Multimodal imaging is essential in both planning and execution of these complex repairs and enables the entire team to fully participate in, understand, and visualize the repair without the need for a sternotomy incision.
Footnotes
Conflicts of interest: M.W.A.C. has received speakers honoria from Medtronic, Edwards Lifesciences, Terumo Aortic, Boston Scientific and Abbott Vascular. The other authors reported no actual or potential conflicts of interest.
Supplementary data related to this article can be found at https://doi.org/10.1016/j.case.2019.11.003.
Supplementary Data
Computed tomography of the chest showing the coronal view of the heart, with the left atrium (LA) divided into two chambers by the membrane. Ao, Aorta; LV, left ventricle; Mn, membrane.
Computed tomography of the chest showing the saggital view of the heart with the left atrium (LA) divided into two chambers by the membrane.
Preoperative echocardiography demonstrating Barlow's disease and moderate to severe mitral regurgitation.
Midesophageal view using TEE demonstrating the membrane (Mn) dividing the left atrium (LA) into two chambers. Color flow Doppler demonstrates flow through the fenestration of the membrane. LV, Left ventricle; RA, right atrium.
The membrane (Mn) is visualized with the fenestration observed medially. LA, Left atrium; LV, left ventricle.
The membrane is resected under endoscopic vision with the mitral valve revealed behind the membrane.
Both TEE and transthoracic echocardiography nicely display a well-seated annuloplasty ring at the mitral annulus with no residual mitral regurgitation. At 6-month follow-up, the incisions are well healed, with two small scars visible at the right lateral chest wall.
References
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Computed tomography of the chest showing the coronal view of the heart, with the left atrium (LA) divided into two chambers by the membrane. Ao, Aorta; LV, left ventricle; Mn, membrane.
Computed tomography of the chest showing the saggital view of the heart with the left atrium (LA) divided into two chambers by the membrane.
Preoperative echocardiography demonstrating Barlow's disease and moderate to severe mitral regurgitation.
Midesophageal view using TEE demonstrating the membrane (Mn) dividing the left atrium (LA) into two chambers. Color flow Doppler demonstrates flow through the fenestration of the membrane. LV, Left ventricle; RA, right atrium.
The membrane (Mn) is visualized with the fenestration observed medially. LA, Left atrium; LV, left ventricle.
The membrane is resected under endoscopic vision with the mitral valve revealed behind the membrane.
Both TEE and transthoracic echocardiography nicely display a well-seated annuloplasty ring at the mitral annulus with no residual mitral regurgitation. At 6-month follow-up, the incisions are well healed, with two small scars visible at the right lateral chest wall.