Background

A circular shunt is defined as a diversion of blood, often times intracardiac, that leads to flow recirculation to the same chamber without traversing a capillary bed. ^{Reference Shone, Anderson, Elliott, Amplatz, Lillehei and Edwards1} Volume overload and low cardiac output are the causes of heart failure. This is a very rare condition, and it has been mostly described as a primary pre-operative condition in Ebstein’s anomaly and other CHDs involving pulmonary artery stenosis or atresia. ^{Reference Shone, Anderson, Elliott, Amplatz, Lillehei and Edwards1–Reference Mustafa, Aghajani, Bairmani and Khalil9} However, only a case post-operative circular shunt has been published, in which IB-type tricuspid atresia underwent right cavo-pulmonary anastomosis without pulmonary trunk occlusion and developed a veno-venous fistula from the left superior vena cava to the coronary sinus with no surgical correction for the circular shunt at the moment of that publication. ^{Reference Krishnamoorthy and Sivasankaran10}

The options for definitive treatment reported so far have included surgical corrections as well as percutaneous procedures, and in the fetal life, the treatment has been transplacentary pharmacological therapy or fetal intervention. ^{Reference Shone, Anderson, Elliott, Amplatz, Lillehei and Edwards1–Reference Mustafa, Aghajani, Bairmani and Khalil9}

The aim of this manuscript is to share the first case of an “iatrogenic” circular shunt, which was resolved percutaneously, and discuss the reflections that this case provides us.

Case report

A 5-month-old girl was referred to our tertiary care hospital with a history of cyanosis and cardiac murmur. A transthoracic echocardiogram allowed diagnosis of situs solitus and levocardia, with total anomalous pulmonary venous connection to the coronary sinus. During the surgical procedure, a persistent left superior vena cava connected to the roof of the left atrium was incidentally found. The total anomalous pulmonary venous connection was corrected with unroofing of the coronary sinus, and its ostium was closed with a polyester patch with continuous suture. Due to the absence of the innominate vein, the surgical team decided to perform an end-to-lateral cavo-pulmonary anastomosis to the left branch of the pulmonary artery. She had an insidious evolution in ICU and was discharged 21 days later with loop and potassium-sparing diuretics.

Upon follow-up, at the age of 6 years, she was found to have failure to thrive, fatigue during feeding, and diaphoresis, with class II modified Ross heart failure classification. Physical examination was relevant for jugular vein distention; a collateral venous network in the neck was observed, along with hyperdynamic precordium, grade II/IV systolic heart murmur on the pulmonary valve area with fixed splitting of the second sound, normal hepatic border, and normal pulses without cyanosis.

Chest X-ray showed cardiomegaly (cardiothoracic index 0.6) and dilatation of right cavities. On electrocardiogram, there was evidence of right chamber overload. Transthoracic echocardiogram revealed an unroofed coronary sinus without obstruction of pulmonary vein flow with a mean gradient of 2 mmHg. Reversal flow in the cavo-pulmonary anastomosis was also detected, along with moderate dilatation of right chambers, an unobstructed right ventricle outflow tract, and preserved biventricular systolic function.

Cardiac catheterisation demonstrated a circular shunt through a 2.2 mm left cavo-pulmonary anastomosis with aneurysmal dilatation of the left superior vena cava and prominent collateral venous circulation draining to the right superior vena cava (Figure 1a and b). Percutaneous closure of the anastomosis was performed with an Amplatzer® ADO 8/6 device (Figure 1c), and she was discharged 24 hours after the procedure. At 7 days follow-up, symptom resolution was noted, and she was continued on aspirin solely. Non-gated cardiac CT angiography was done at 14 years of age (Figure 2) which showed an occluder device appropriately placed with multiple veno-venous collaterals between the left superior vena cava and the right superior vena cava. One year afterwards, she continues asymptomatic without medications in the last transthoracic echocardiogram; the right chamber size is normal without enlargement with conserved biventricular function.

Figure 1.

( a ) Right ventriculography: we can see contrast medium over the left branch of pulmonary artery. ( b ) We can see the left cavo-pulmonary anastomosis (arrow) and the aneurysmatic dilatation of the LSVC. ( c ) An Amplatzer® ADO device occluding left cavo-pulmonary anastomosis. LSVC, left superior vena cava.

Figure 2.

Non-gated cardiac CT-angiography: we can see Amplatzer® ADO device occluding left cavo-pulmonary anastomosis (arrow). ( a and b ). Anterior-lower view. ( c ). Posterior view.