Thoracoscopic Resection of a Massive Atrial Myxoma Causing Functional Mitral Stenosis

An otherwise healthy 58-year-old woman was evaluated for lower back and abdominal pain. She underwent a computed tomography scan of the abdomen, and the upper abdominal slices revealed a hypodense lesion occupying the left atrium (LA). The patient had no signs or symptoms of heart failure, but she did have a "positional" middiastolic murmur. A transthoracic echocardiogram revealed a large 5 x 4 cm mass occupying the LA, causing mild mitral stenosis with a diastolic transvalvular gradient of 3.5 mm Hg. The mass was prolapsing into the left ventricle (LV) during diastole. Preoperative cardiac catheterization revealed a tumor blush originating from a feeding vessel from the proximal right coronary artery. Cardiac magnetic resonance imaging better revealed the diastolic prolapse into the LV. Based on these findings, the decision was made to perform a thoracoscopic resection of the LA mass.

The exposure has been described before. The patient was intubated with double lumen endotracheal tube and positioned in a semilateral position. A 3 cm incision was made, and the right chest was entered at the fourth intercostal space. A transseptal approach was chosen for entering the LA. Bicaval cannulation was performed with a 15 Fr arterial Bio-Medicus™ cannula placed percutaneously in the superior vena cava under transesophageal echocardiographic (TEE) guidance prior to positioning the patient. The right femoral vein was cannulated with a 22 Fr vacuum assist venous cannula (Edwards Lifesciences), and the tip was placed in the inferior vena cava under TEE guidance. A 16 Fr Fem-Flex cannula was used for arterial return in the right femoral artery. Both the femoral artery and femoral vein cannulations were performed under ultrasound guidance. Two Perclose sutures were placed in the femoral artery and one Perclose suture was placed in the femoral vein in order to allow the cannulation and closure of the cannulation sites to be performed totally percutaneously. Both cavae were snared with looped umbilical tapes, an antegrade cardioplegia cannula was inserted in the proximal ascending aorta, and the aorta was cross-clamped with a transaxillary clamp.

The right atrium was opened with an incision parallel to the right atrioventricular groove and the fossa ovalis was incised. The tumor stalk was identified, and it was attached to the lateral atrial wall as well. The tumor was massive, and careful attempts were performed to deliver it en bloc through the incision of the fossa ovalis.

This was unsuccessful, and the remaining mass was removed with extreme caution to avoid any dislodgement. After the mass was removed, it was evident that there was a residual tumor stalk attached to the lateral atrial wall. A pericardial suture was used to bring the stalk into better view, and this was resected as well. Reconstruction of the interatrial septum and lateral atrial wall was performed using bovine pericardium. Sutures were placed carefully in order to reapproximate the endothelial surface of the atrial wall. The sutures were tied down using minimally invasive instruments. The aortic cross-clamp was removed, the heart was allowed to beat, and the right atrial atriotomy was closed in a regular fashion.