Introduction
Since Fontan and Baudet introduced their technique for treating single-chamber hearts, the method has undergone numerous modifications.Reference Fontan and Baudet1,Reference Rychik, Atz and Celermajer2 In high-risk patients, fenestration improves treatment outcomes by relieving venous congestion, enhancing systemic output, and reducing early mortality and morbidity.Reference Rychik, Atz and Celermajer2,Reference Jalal, Gewillig and Boudjemline3 Conversely, spontaneous fenestration closure can indicate haemodynamic stabilisation. Moreover, fenestration closures reducing embolisation risks and enhancing saturation levels, exercise tolerance, and tissue oxygenation.Reference Kawasaki, Sasaki, Forbes, Ross and Kobayashi4–Reference Mays, Border and Knecht6 Adjusting fenestration size based on individual conditions may achieve better outcomes.Reference Jalal, Gewillig and Boudjemline3 Several reports detail techniques for partial fenestration occlusion to control shunt volume, including multiple or covered stent implantations, snares, and atrial flow regulating devices.Reference Stümper, Gewillig and Vettukattil7–Reference Lehner, Schulze-Neick and Haas10 However, reducing flow in large, stented fenestrations remains challenging. We present a technique for partial fenestration occlusion utilising a coronary stent and a vascular occluder (Supplementary Video).
Case
A 9.5-year-old girl (21 kg) diagnosed with hypoplastic left heart syndrome and Turner’s syndrome, post-Fontan palliation, and a large fenestration stented with two (5- and 6-mm) stents was referred due to progressive desaturation below 80% and declining exercise capacity.
At 2.5 years of age (14 months post second stage palliation), she underwent cardiac catheterisation, with an 8 x 18 mm Palmaz Genesis (Cordis) stent implanted in the left pulmonary artery and an aortopulmonary collateral embolisation. Nineteen months later, the left pulmonary artery stent was re-dilated using a 10 mm PowerFlex balloon (Cordis), along with embolisation of both internal thoracic arteries. A year later, she underwent extracardiac Fontan completion with a 3 mm fenestration, tricuspid valve plasty, and left pulmonary artery stent re-dilation. A month later, cardiac catheterisation due to persistent chylothorax showed mean pressures of 16 mmHg in the superior caval vein, 14 mmHg in the LPA, and 11 mmHg right ventricle end-diastolic pressure. According to the available documentation, a 5 x 15 mm Palmaz Blue (Cordis) stent was implanted. However, due to migration of the stent towards the atrium, an additional 6 x 18 mm Palmaz Blue stent was deployed to stabilise the first sent and prevent from embolisation.
We catharised the child for the first time at the age of 8 years. The mean pressures in the tunnel and the left pulmonary artery were 15 and 14 mmHg, respectively. The right ventricle end-diastolic pressure was 10 mmHg, and aortic oxygen saturation was 86.6%. The pulmonary-to-systemic flow ratio (Qp:Qs) was 0.76, and the cardiac index (CI) was 5.5 l/min/m2. The fenestration occlusion test resulted in a marginal tunnel pressure increase, unchanged systemic arterial pressure, and increase of percutaneous oxygen saturation from 84 to 96%. The Qp:Qs ratio rose to 1.1 and CI decreased to 3.7 l/min/m2.
Following discussions with the patient’s primary cardiologist and surgeon, considering the complex post-Fontan course, it was decided to maintain the fenestration open, increase sildenafil dosage, and reevaluate the possibility of closure.
Approximately one year later, following intensification of sildenafil therapy, catheterisation was focused on reducing the size of the fenestration. Haemodynamic parameters revealed mean Fontan and eight ventricle pressures of 13 and 71/10 mmHg, respectively, with aortic oxygen saturation at 84% (with 30% inhaled oxygen). The calculated Qp:Qs was 0.78. Initial angiography indicated mild left pulmonary artery stent stenosis, with a patent stented fenestration exhibiting significant right-to-left flow [Figure 1(a)]. The left pulmonary artery stent was re-dilated using a 12 mm high-pressure Atlas balloon catheter (Bard). Subsequently, a 4 Fr Berenstein (Cordis) catheter was passed through the stented fenestration, followed with a 0.035 stiff wire anchored in the left upper pulmonary vein and a 7 Fr long sheath inserted into the stented fenestration. Maintaining the long sheath trough the fenestration, a 0.014 wire (Terumo) was anchored in the right lower pulmonary vein, allowing for introduction a 4 x 18 mm Multi-Link coronary stent (Abbott) into the stented fenestration. The Berenstein catheter was loaded with a 6 x 11 mm Amplatzer Vascular Plug IV (Abbott) [Figure 1(b)]. Subsequently, the Amplatzer Vascular Plug IV was gently uncovered alongside the coronary stent, but not yet released from the delivery system [Figure 1(c)], and the coronary balloon was inflated [Figure 1(d)]. Finally, upon releasing the vascular occluder, the coronary ballon catheter was removed, and proper position of the devices within the fenestration, with limited right-to-left contrast flow, was confirmed angiographically [Figure 1(e)]. Mean pressure in the tunnel and systemic pressures were 13 mmHg and 70/40/52 mmHg, respectively. The calculated Qp:Qs improved to 0.85 and oxygen saturation increased to 89%. Pre-discharge echocardiography revealed a patent stented fenestration with limited flow [Figure 1(f)] and a mean gradient of 3 mmHg. Room air oxygen saturation ranged from 89 to 91%.
Step-by-step presentation of reduction of large, stented fenestration a in a patient after Fontan circulation. (a): Initial angiography: previously stented fenestration (5 x 15 mm and 6 x 18 mm Palmaz Blue stents; Cordis), with significant right-to-left contrast flow (white empty asterisk). (b): A 4 Fr Berenstein (Cordis) catheter (black empty arrow) loaded with a 6 x 11 mm Amplatzer Vascular Plug IV (APV IV; Abbott; black arrow) and a 4 x 18 mm Multi-Link (Abbott) coronary stent (white arrow), advanced into the previously stented fenestration. (c): The AVP IV (black arrow) uncovered from the delivery catheter (black empty arrow). (d): Balloon inflation (white empty arrow) of the coronary stent (white arrow). The AVP IV (black arrow) not yet released from the delivery system (black empty arrow), filling the space between previously implanted stents and the new coronary stent (black arrow). (e): Final angiography – limited flow (white empty asterisk) through the coronary stent (white arrow) implanted into the previously stented fenestration. The released vascular plug (black arrow) filled the space between walls of the previously implanted stents and a newly implanted coronary stent. (f): Follow-up transthoracic echocardiogram – limited right-to-left flow through the coronary stent implanted into the primarily stented fenestration. LAO - Left Anterior Oblique.
The patient was discharged on enalapril, spironolactone, sildenafil, and anticoagulation medications including aspirin and acenocoumarol. In the 12-month follow-up, repaeated echocardiograms indicated a 3 mm diameter patent stented fenestration with a mean gradient of 3 mmHg. Oxygen saturation consistently exceeded 90%, with improved exercise tolerance. The patient remains on dual anticoagulation therapy to prevent fenestration occlusion or thromboembolic complications.
Discussion
Fenestration creates a bypass between venous return and the single ventricle, crucial post-Fontan procedure due to its haemodynamic impacts. Reference Rychik, Atz and Celermajer2 The fenestration size is critical: too small increases pulmonary congestion and venous pressure, while too large improves cardiac output but leads to oxygen desaturation and exercise intolerance. Haemodynamic stability might not need fenestration, but in cases of high pulmonary vascular resistance and low ventricular filling, optimal fenestration size balances congestion, venous pressure, and cyanosis. Fenestration can be created during initial surgery or percutaneously via needle or radiofrequency perforation. Reference Jalal, Gewillig and Boudjemline3 Conversely, Fenestration closure is considered for chronic cyanosis and limited exercise tolerance, targeting patients without postoperative complications.Reference Kawasaki, Sasaki, Forbes, Ross and Kobayashi4–Reference Mays, Border and Knecht6 Techniques for enlarging or narrowing fenestration include ballooning, stenting, or using an atrial flow regulator. Narrowing is indicated for excessive shunting and cyanosis, using methods like multiple or covered stents, partial collapse of a pre-existing stent with a snare, or atrial flow regulator device implantation.Reference Stümper, Gewillig and Vettukattil7–Reference Lehner, Schulze-Neick and Haas10
In our patient, initial fenestration enlargement stabilised the post-Fontan course but led to significant right-to-left shunting over time. Adjusting flow within the previously implanted stents using a new coronary stent and vascular occluder proved safe and effective in the mid-term follow-up. This innovative approach presents a viable alternative in managing fenestration shunting, allowing both flow reduction and the possibility for future enlargement if required.
Conclusion
In selected patients, partial fenestration closure, although challenging, may improve blood oxygen saturation, organ function, and exercise tolerance while providing a safety valve. Despite challenges in reducing stented fenestration diameter, the array of available devices and techniques ensures its effectiveness and safety.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S1047951125001751.
Acknowledgements
The authors thank Anna Grondalski from Pomeranian Medical University for editing the text.
Financial support
None.
Competing interests
None declared.
