Superior Vena Cava Stenosis Manifesting with Brain Abscess 2 Decades after Atrial Septal Defect Repair

Supplemental material is available for this article.

Key Points

• ■ It is important to have a low index of suspicion for a systemic-to-pulmonary venous shunt in patients presenting with a brain abscess, especially in the setting of congenital heart disease.

• ■ The physician should be able to develop a differential diagnosis of anatomic defects causing right-to-left shunt.

• ■ Multimodality imaging plays an essential role in the postoperative evaluation of congenital cardiomyopathies, and the identification of late postprocedural complications is crucial for the appropriate treatment of these patients.

Introduction

Superior vena cava (SVC) stenosis has been described as a rare complication of atrial septal defect surgical repair, especially for the superior sinus venosus type with partial anomalous pulmonary venous drainage, in which the SVC is surgically manipulated.

Contrary to an acute SVC occlusion that manifests with the classic signs and symptoms of SVC syndrome—facial and neck swelling, dyspnea, plethora—an insidious SVC obstruction can go unrecognized because of the development of venovenous collateral circulation. This alternative drainage pathway allows the patient to remain oligo- or asymptomatic for a longer period of time.

We report a case of SVC stenosis with development of intrapulmonary venovenous collaterals, first manifesting with a brain abscess 21 years after atrial septal defect repair.

Case Report

A 23-year-old woman presented to the emergency department with 1 week of progressive bilateral frontal and parietal headaches with nausea, vomiting, photophobia and phonophobia, dizziness and weakness, as well as two episodes of syncope. The patient denied fever or chills or a prior history of headaches. She had a history of atrial septal defect surgical repair at 2 years of age and subsequently was lost to follow-up. On presentation, the patient was in no acute distress, afebrile, normotensive, and acyanotic (oxygen saturation, 95% on room air). Heart rate and rhythm were normal, and there were no cardiac murmurs. The findings of the neurologic examination were normal.

Images from CT of the head and subsequent MRI of the brain showed a large right frontal lobe mass with vasogenic edema, suggestive of a frontal abscess (Fig 1). The patient underwent emergent right frontal craniotomy with evacuation of the abscess without complications. Culture of surgical material revealed Streptococcus intermedius, and the patient was treated with ceftriaxone.

Figure 1:

MRI of the brain. A, Diffusion-weighted and, B, postcontrast T1-weighted images show a right frontal ring-enhancing lesion with restricted diffusion compatible with an abscess.

The diagnostic workup of a patient presenting with a brain abscess includes excluding infective endocarditis and a right-to-left venous shunt, especially in the setting of a history of congenital heart disease. The right-to-left shunt would allow pathogens in the venous bloodstream to bypass the defenses of the pulmonary capillary bed, gaining free access to the arterial circulation.

A transthoracic echocardiogram with agitated saline injection revealed initial intense opacification of the left chambers following the saline injection through a left arm peripherally inserted central catheter (Fig 2, Movie 1 [supplement]), followed by faint opacification of the right chambers. In the presence of an interatrial communication, one would expect agitated saline to opacify the right atrium prior to the left atrium. A left SVC to an unroofed coronary sinus without a bridging vein was suspected. The history of congenital heart defect and the findings on the saline contrast media injection transthoracic echocardiogram warrant further investigation of the systemic venous anatomy via cross-sectional imaging (1–3).

Figure 2:

Still frame of echocardiogram with agitated saline (apical four-chamber view) demonstrates intense initial opacification of the left chambers.

Movie 1.

Download video file ^{(11.1MB, mp4)}

Echocardiography with agitated saline injection shows immediate initial opacification of the left chambers.

Findings from cardiac MRI demonstrated normal biventricular size and function (left ventricular end-diastolic volume index, 70 mL/m²; left ventricular ejection fraction, 67%; right ventricular end-diastolic volume index, 71 mL/m²; right ventricular ejection fraction, 56%). Severe stenosis of the SVC–right atrial junction was noted. Flow in the innominate vein was retrograde, draining directly to the left upper lobe via an anomalous left upper pulmonary vein. Intrapulmonary venovenous collaterals connected the left upper pulmonary vein to a large accessory vein that drained into the left atrium (Movie 2 [supplement]). The remaining pulmonary veins connected normally to the left atrium. Surgical material noted in the proximal SVC, as well as its connection to the right atrial appendage, suggested a prior Warden procedure for a superior sinus venosus defect (SVD), in which the SVC is transected and connected to the right atrial appendage with baffling of the right upper pulmonary vein to the left atrium (Figs 3, 4).

Figure 3:

A, Image from transthoracic echocardiography with agitated saline injection of region of the superior vena cava–right atrial appendage anastomosis (yellow arrow) demonstrates surgical material and severe stenosis. B, Maximum intensity projection reformat shows anomalous connection from the left upper pulmonary vein to the left innominate vein (white arrow). Large venovenous intrapulmonary collaterals (blue arrow) connect the left upper pulmonary vein to a large accessory vein (red arrow) that drains into the left atrium. The left lower pulmonary vein drains normally to the left atrium (black arrow).

Figure 4:

Volume-rendered three-dimensional reconstruction. Region of the superior vena cava–right atrial appendage anastomosis (yellow arrow), anomalous connection from the left upper pulmonary vein to the left innominate vein (white arrow), and large venovenous intrapulmonary collaterals (blue arrow).

Movie 2.

Download video file ^{(1.9MB, mp4)}

Bolus tracking MR angiography sequence. Contrast is injected through a right peripherally inserted central catheter and progresses to the innominate vein into the anomalous left upper pulmonary vein, then through intrapulmonary venovenous collaterals back to the left atrium.

A right heart catheterization was performed to relieve the SVC stenosis. The SVC–right atrial anastomosis was nearly completely occluded (Movie 3 [supplement]) and was accessed simultaneously via the right jugular and right femoral veins. A covered stent was placed in the area of stenosis without complication (Fig 5). Subsequent contrast agent injection in the SVC showed antegrade flow in the left upper pulmonary vein and innominate vein. No residual flow was seen through the intrapulmonary collateral system. The patient was prescribed 75 mg of clopidogrel daily and discharged home.

Figure 5:

Still images from Movie 3 (supplement) of right heart catheterization show, A, stenosis at the superior vena cava–right atrial junction, B, superior vena cava–right atrial anastomosis after balloon dilation, and, C, covered stent placement with, D, satisfactory flow.

Movie 3.

Download video file ^{(5MB, mp4)}

Fluoroscopy cine demonstrating almost total occlusion of the superior vena cava and the intrapulmonary collaterals.

Discussion

When assessing postsurgical cardiovascular complications, it is important to choose the one imaging modality that best answers the clinical question, taking into account different patient characteristics such as age, renal function, and hemodynamic stability. In our case, MRI was considered the method of choice, as it allows anatomic visualization and functional evaluation in an adult patient without sedation while avoiding exposure to ionizing radiation. Electrocardiographically gated multidetector CT is usually widely available and would allow excellent three-dimensional evaluation of cardiovascular structures. However, high heart rate and arrhythmias are important limitations of the method. Especially in young patients, avoiding ionizing radiation is a high priority, and prior severe allergic reactions and renal dysfunction are known contraindications of iodinated contrast media.

SVC stenosis is generally related to surgical injury, indwelling catheters or pacemaker leads, infection, thrombosis, or malignancy. In our case, the patient developed SVC stenosis after cardiac surgical repair in childhood, which had gone unrecognized for more than 20 years. In one series, only half of the patients with SVC obstruction presented with classic signs of obstruction such as SVC syndrome, pleural effusions, ascites, or frequent chest infections (4). In that same series, only 10% of patients who developed SVC stenosis after cardiac surgical repair presented with acute symptoms of SVC obstruction. SVC obstruction can be insidious and thus go unrecognized because collaterals form via the intercostal veins and azygous and hemiazygos circulation to restore the venous circulation (5).

The cardiac MRI findings suggested a Warden procedure, which is the procedure of choice for surgical correction of a superior SVD per current guidelines (6). However, we could not clearly distinguish a patch redirecting the right upper pulmonary vein to the left atrium, which can be difficult many years following the repair of small defects. SVC stenosis has been described as a rare complication after repair of a superior SVD where the SVC is involved in the defect and surgically manipulated (7,8).

In the superior type of SVD, there is a deficiency of the common wall between the SVC and the right upper pulmonary vein resulting in anomalous drainage of the right upper pulmonary vein into the right atrium and biatrial drainage of the SVC (1). It is often associated with additional anomalous pulmonary venous connections.

The previously unrepaired connection between the left upper pulmonary vein and the innominate vein allowed the decompression of the upper body venous circulation into the left lung. The insidious development of intrapulmonary venovenous collaterals eventually draining into the left atrium via an accessory pulmonary vein created a systemic-to-pulmonary venous shunt and allowed the SVC obstruction to go unrecognized. This also facilitated the hematogenous spread of the bacteria, resulting in a brain abscess.

Percutaneous intervention has been described as treatment of various causes of SVC stenosis, with greatly satisfactory results for both stent and balloon angioplasty, with no difference in the long-term success between the modalities (4,9).

Our patient underwent percutaneous covered stent placement with excellent re-establishment of laminar flow. Follow-up transthoracic echocardiogram demonstrated laminar flow across the SVC stent. Flow in the innominate vein and left upper pulmonary vein was antegrade. No right atrial or right ventricular dilatation is seen.

Stenosis of the SVC is a known complication of SVD surgical repair, which can be progressive, culminating with the development of collaterals. The SVC can be difficult to assess with transthoracic echocardiography in adults with congenital heart disease, and therefore, cross-sectional imaging plays an important role in assessing the location, severity, and cause of the SVC obstruction. It is of great importance for the imager to assess for SVC stenosis after SVD repair. In our case, the partial anomalous pulmonary venous drainage and intrapulmonary collateralization resulted in a systemic-to-pulmonary venous shunt, which ultimately led to the development of brain abscess.