(P249) CAVO-ATRIAL BYPASS FOR CARDIAC COMPLICATIONS FROM ROSAI-DORFMAN DISEASE

Case background: Rosai-Dorfman disease (RDD) is a non-malignant disease of histiocyte proliferation. The etiology of RDD is poorly defined, with both viral and genetic contributions reported. RDD classically presents with painless cervical lymphadenopathy, although extranodal involvement has been reported in 1/3 of patients. Cardiac involvement is documented in < 0.1% of cases. We present a case of cardiac RDD with obstruction at the inferior vena cava (IVC) – right atrial (RA) junction resulting in multisystem organ dysfunction.

Management Challenges: A 63-year-old female presented to medical attention with non-exertional chest pain and presyncope. She was in atrial flutter without evidence of acute coronary syndrome. A transthoracic echocardiogram showed increased flow velocities (1.4 m/sec) in the pulmonary veins (PV). A cardiac computed tomography scan revealed asymmetric left atrial (LA) thickening with narrowing of the right-sided PVs. Cardiac magnetic resonance imaging showed a soft tissue mass arising from the base of the interatrial septum (IAS) partially obstructing the right-sided PVs and mildly narrowing the superior vena cava (SVC) inflow. A positron emission tomography (PET) scan showed no evidence of malignant metastasis. Oncologic evaluation required a biopsy for definitive diagnosis; however, given the unusual location and appearance of the mass, a percutaneous approach was not possible. Cardiac surgery was consulted for an open diagnostic biopsy as the extensive nature of the tumour precluded tumour debulking or definitive resection.

After median sternotomy, cardiopulmonary bypass (CPB) was achieved via central aortic cannulation and peripheral bicaval cannulation. A firm mass was found to be distorting RA with extensive sub-epicardial infiltration of the LA and IAS impinging on the right-sided PVs. A biopsy was taken from the IAS at the fossa ovalis which was repaired with a bovine pericardial patch. An intraoperative frozen section showed features consistent with reactive, infiltrative, or lymphoproliferative disease. Post-CPB transesophageal echocardiogram (TEE) showed preserved biventricular function, no shunt across the interatrial patch, with no change in the right PV drainage. No obvious RA-IVC obstruction was initially seen. The patient was transferred to the intensive care unit (ICU) on high-dose vasopressor.

On postoperative day 0 (POD0), the patient showed signs of obstructive shock. Mediastinal re-exploration showed no tamponade or other obvious abnormalities. She was transferred to the ICU where she continued to require high-dose vasopressor support with end-organ damage. A bedside TEE showed moderate to severe dilation of the IVC and hepatic vein with near complete obstruction of the IVC at the IVC-RA junction. The patient was initially treated with high-dose steroids for a presumptive diagnosis of cardiac lymphoma. On POD2, her clinical status continued to worsen with a presumptive diagnosis of cardiogenic shock due to severe IVC obstruction. A venogram confirmed a high grade stenosis of the suprahepatic IVC with collateral drainage via the hemiazygous system. Veno-venous bypass of the obstruction was initiated using extracorporeal membrane oxygenation (VV-ECMO). After extensive pathologic investigation, the diagnosis of RDD was confirmed on POD10. As no improvement was seen after 10 days of high-dose steroids and the patient was unable to be weaned off of VV-ECMO, multidisciplinary consensus was that surgical extra-anatomic bypass to circumvent the IVC obstruction would offer the best option for immediate therapy which could then be followed by systemic therapy.

On POD16 the patient underwent open cavo-atrial bypass. Intraoperative TEE showed a large mass extending from the LA and IAS with displacement of the RA and obstruction at the RA-IVC junction. Following an uncomplicated sternal re-entry, the liver was mobilized to expose the retrohepatic IVC. Heparin was given. A 12 mm polytetrafluoroethylene (PTFE) vascular ring graft (W. L. Gore & Associates, Inc., Newark, DE) was anastomosed to the retrohepatic IVC in an end-to-side fashion using a running 4-0 polypropylene suture. The graft was tunnelled through the diaphragm immediately adjacent to the IVC. The patient was fully heparinized and full CPB proceeded with cannulation of the distal ascending aorta and using the VV-ECMO cannulae. The SVC and IVC were clamped and the RA appendage was opened. The proximal end of the 12 mm PTFE graft was anastomosed to the RA appendage in an end-to-end fashion using a running 5-0 polypropylene suture. The graft was deaired and patient was weaned from CPB. The chest and abdomen were closed in usual fashion and patient was returned to ICU in stable condition. The patient made an uncomplicated recovery and was discharged home. Her RDD was treated with a planned 4-week course of rituximab pending results of her molecular testing to further guide targeted therapy options. Regular outpatient PET scans were scheduled to assess for response to rituximab as well as to identify any other focus of disease involvement.

RDD of the heart is extremely rare but may primarily present with cardiac symptoms rather than classic constitutional symptoms. While most primary cardiac masses are benign, definitive diagnosis with a tissue biopsy in a timely manner is paramount. In certain circumstances, sternotomy for a cardiac tissue biopsy may be necessary. Although RDD is a generally benign disease, extensive involvement of vital organs may cause life-threatening complications. In the present case, cavo-atrial bypass was a bridge-to-treatment that spared the patient from long term VV-ECMO while allowing time for systemic therapy to achieve eventual regression of the mass.

There are multiple potential therapies for this disorder. While surgical resection could be considered with more localized cardiac involvement, it was not possible in this case due to the extensive and infiltrative nature of the disease. Furthermore, its very hard texture precluded a debulking strategy. Systemic therapy includes steroids, immunomodulatory therapy, and chemotherapy. There is no consensus on the optimal chemotherapeutic agents and often a trial of different agents may be necessary. As systemic therapy for RDD may have a slow and unpredictable response, a therapy to allow temporary lower body drainage into the RA while the tumor responds and shrinks was necessary. As prolonged VV-ECMO is associated with complications, surgical shunt as a temporizing solution was felt to be the best option. Although cavo-atrial bypass has been previously described to relieve other causes of IVC obstruction, this is a novel approach for RDD-related cardiac involvement.