a 12-month - old girl underwent a complete repair of tetralogy of fallot that included a ventricular septal defect closure and right ventricular outflow tract ( rvot ) reconstruction . on the preoperative echocardiogram ,
rvot reconstruction was performed with an infundibulectomy , infundibular patch enlargement , pulmonary valvotomy , and pulmonary angioplasty .
a thin walled gore - tex ( w.l . gore and associates , flagstaff , az , usa ) vascular graft was used as the material for an infundibular patch , which was attached to the rvot with a continuous 6 - 0 poly - propylene ( surgipro ; covidien , mansfield , ma , usa ) running suture .
on intraoperative transesophageal echocardiography , the pulmonary valve residual pressure gradient was 49 mmhg and systolic pressure ratio between the right and left ventricles was 0.8 mmhg . however , we could not place a trans - annular patch because the patient had an anomalous coronary artery crossing the rvot . the left anterior descending artery originated from the right coronary artery crossing the rvot ( fig .
, we did not continue the procedure and treated the patient with a beta - blocker .
one month later , the patient was readmitted to kyungpook national university hospital complaining of cough , shortness of breath , and facial and upper extremity oedema over the previous three days .
chest radiography revealed enlargement of the left upper cardiac border with a left pleural effusion ( fig .
in addition , transthoracic echocardiography showed a large aneurysmal dilatation of the rvot with narrowing of the superior vena cava and main pulmonary artery , secondary to compression by the aneurysm .
computed tomography ( ct ) showed a narrow communication between the rvot and an aneurysmal sac . through these findings
because of the risk of a spontaneous rupture , we elected to perform emergency surgery .
a careful median resternotomy was performed . a large serous pericardial and pleural effusion was present around the rvot . under cardiopulmonary bypass ,
the aneurysmal sac was opened , revealing patch dehiscence at the proximal suture line between the infundibular patch and the ventriculotomy site .
communication between the rvot and the pseudoaneurysm was confirmed , and the previous infundibular patch and all aneurysmal tissue were excised .
however , in this procedure , the infundibular patch was attached to the rvot with multiple interrupted pledgeted mattress sutures as well as full - thickness bites in the suturing of the right ventricular wall .
intraoperative transesophageal echocardiography showed residual pulmonary stenosis ( pressure gradient , 36 mmhg ) and normal right ventricular systolic function .
the patient s postoperative course was uneventful , and both her facial and upper extremity oedema improved .
postoperative transthoracic echocardiography , performed eight months after the reoperation , showed residual pulmonary stenosis ( pressure gradient , 36 mmhg ) without any indication of the development of an aneurysm .
pseudoaneurysm of the rvot is an infrequent complication of cardiovascular surgical procedures that involve both a right ventriculotomy and rvot reconstruction with patch repair or conduit replacement [ 13 ] .
the pathogenesis and aetiology of pseudoaneurysms have been described as related either to obstructive rvot or to elevated right ventricular systolic pressure , leading to mechanical strain at the proximal suture line .
however , other contributing factors such as pulmonary insufficiency , suture material and technique , trauma , complete heart block , and infection have also been implicated [ 13 ] .
regardless of the aetiology , a pseudoaneurysm arises from the small dehiscence of a portion of the reconstructed rvot , permitting blood leakage into the surrounding space and resulting in a pericardial haematoma [ 14 ] . in this case
, the pseudoaneurysm may have been caused by residual rvot obstruction , especially because of inappropriate suture techniques , such as continuous running sutures and partial - thickness sutures in the right ventricular wall .
follow - up transthoracic echocardiography , performed eight months after reoperation , showed no aneurysmal changes in the rvot .
however , pseudoaneurysms progressively increase in size and may present , albeit rarely , alongside symptoms secondary to the compression of adjoining mediastinal structures , rupture , thromboembolism , and infection [ 14 ] . in the present case ,
superior vena cava syndrome was caused by compression of the superior vena cava , which was a very unusual presentation .
transthoracic echocardiography has been reported as a reliable method for diagnosing pseudoaneurysms [ 14 ] .
however , it does not provide detailed information about the anatomical relationship between the pseudoaneurysm and surrounding structures .
we found ct to be very helpful in evaluating the location and size of the pseudoaneurysm and determining its anatomical relationships .
ct was also useful in evaluating the safety of performing another sternotomy in light of the possible need for femoral or neck vessel cannulation before another sternotomy .
preoperative magnetic resonance imaging may also provide information helpful in choosing the best surgical approach .
however , magnetic resonance imaging is more time - consuming than ct , and is difficult to perform in haemodynamically unstable patients .
compared to true aneurysms , pseudoaneurysms pose an increased risk of rupture because of the absence of myocardial tissue in their walls . therefore , they are potentially life threatening if not treated . once diagnosed , pseudoaneurysms require either reoperation or another intervention . in conclusion ,
it should always be suspected in patients with the relevant symptoms , and such patients must be followed up closely .
precise and careful preoperative assessment , using echocardiography and ct , is important for ensuring the safety of surgery performed on these patients .
 pseudoaneurysm of the right ventricular outflow tract ( rvot ) has been reported as a rare complication of rvot reconstruction performed using conduit replacement or patch repair . 
 rarely , it may present alongside symptoms secondary to the compression of adjoining mediastinal structures . 
 we report the case of a patient who developed a symptomatic rvot pseudoaneurysm one month after a total correction of tetralogy of fallot . in the present case , 
 superior vena cava syndrome was caused by compression of the superior vena cava , which was a very unusual presentation . 
CASE REPORT
DISCUSSION