Interventional Glenn as a novel therapeutic option to unload the right ventricle or improve oxygen saturation in selected adult congenital heart disease patients

Background: Some patients with univentricular physiology or with Ebstein-Anomaly (EA) encounter progressive RV dysfunction or cyanotic conditions. The Glenn-Shunt (or partial cavo-pulmonary connection, PCPC) is used to unload the ventricle by redirecting the venous return form the superior vena cava (SVC) directly to the pulmonary artery (PA), in cases in which pulmonary vascular resistance (PVR) is low to allow passive venous drainage of the SVC through the lungs. It was first introduced to reduce hypoxemia in patients with tricuspid atresia. As a novel therapeutic option, creation of an interventional PCPC (iPCPC) by stent-based connection of the SVC to PA is established in our center. In this abstract we discuss two exemplary cases of adult congenital heart disease (ACHD) patients, in which an iPCPC can be a therapeutic option (to improve oxygen saturation or unload the RV).

Case presentation: In Case 1 we present a 67-year-old male patient who presented to our ACHD center with dyspnea due to progressive desaturation (65% at rest, below 60% upon daily activities), despite optimal medical treatment. He has a native congenital corrected transposition of the great arteries (ccTGA), large ventricular septal defect (VSD), small right ventricle, resulting in functionally univentricular physiology (image A), and severe pulmonary stenosis. In all cases of interventionell Glenn, heart catheterization excluded pre- or post-capillary pulmonary hypertension (Case 1: mean PA-pressure 14 mmHg, wedge-pressure 12 mmHg), and showed a well-developed pulmonary vascular bed. iPCPC was performed as a two-staged-procedure. First, a stent was implanted (Optimus XXL 43) in the SVC via right jugular vein to create an anchoring/ landing zone for the planned Glenn-Anastomosis by covered stent (image B). After a healing phase of about eight weeks, the second stage of transcatheter completion followed. Via jugular venous access, needle puncturing from the SVC (distally to the pre-stent) to the right pulmonary artery (PA) was performed and covered stents were positioned across the puncture site, proximally anchoring in the SVC-pre-stent, distally in the RPA, establishing the Glenn anastomosis. Angiography demonstrated unhindered venous blood flow from the SVC to RPA (image C). After iPCPC, oxygen saturation increased to about 75% without significant decrease under physical activity and no subjective dyspnea. This positive effect sustained after a follow-up period of 12 months.
In Case 2 (not illustrated in this abstract but in final case presentation), we discuss a case of a 58-year-old female patient with uncorrected EA, in which the RV was massively dilated with markedly impaired function (no pulsatile flow in RV and PA) and a decline on oxygen saturation. After assessment and the lack of other therapeutic options, an interventional Glenn was established by the above-mentioned two-staged approach (SVC presenting with Andra XXl stent, creation of SVC-PA-connection by another Andra XXl stent) to volume-unload the impaired RV in the presence of low PVR. The patient’s condition stabilized afterwards.

Learning objectives: Interventional Glenn can be a novel therapeutic option for distinct ACHD patients. This is for example the case in cyanotic univentricular patients, to direct venous flow to the PA and subsequently improved oxygenation or volume-unload the impaired RV such in EA under the premise, that pulmonary blood flow is unhindered (low PVR).