When the Bidirectional Glenn is an Unfavorable Option: Primary Extracardiac Inferior Cavopulmonary Connection as an Alternative Palliation

The current follow-up extends out to 14 months for the first baby and 8 months in a second patient in whom the primary IVC-PA connection has been performed. Both still have oxygen saturations in the high 80's and are thriving. A diagnostic catheter planned for the time of what would give potential pre-Fontan data may tell us what potential veno-venous collaterals may have developed and if they are significant, if pulmonary arterio-venous malformations have been avoided, and if completion TCPC is necessary or may be indefinitely delayed.

Good option for the selective patients where Superior Cavo Pulmonary Anastomosis can not be done. Added advantage is the delivery of Hepatic factor to the lungs to prevent Pulmonary AV malformations. Quick question - Could you use any other conduit, Other than Goretax tube ? Of course advantages of Goretax over other materials is well known and Most of us have good experience with it for Extracardiac TCPC completion. Second question - Do you need to use some form of Anticoagulation like warfarin ? Something similar like to what many of use after Extracardiac TCPC with Goretax conduit.

thank you for your questions. 1. we arbitrarily used photofixed bovine pericardium to fashion rolls which aren't exactly tubes, with the thought that we may need some flexibility to fit in whichever shape is necessary behind the cardiac mass and aorta on the distal part of the anastomosis to the PA's. in retrospect, probably a simple Goretex tube with a bevel would also have been fine, and i think it's what i'll use in the future. for the second question, we've arbitrarily used aspirin, as we do for our usual Glenn's and Fontan's, but i know that some centers systematically put their Fontan patients on warfarin: it's open to debate and was empirical from our standpoint; perhaps they may need more with future follow-up.

ADK- this video is very cool. As you have most likely done a few more "Southern Glenn's" by now, can you tell us more about the follow up of the cohort going forward in time ? Sats? Anticoagulant management and over time? Strategy moving forward for total cavopulmonary connection? This is a very interesting and progressive idea. Congrats!

Hi Daniel, thank you for your kind comments. as mentioned above, the follow-up is at 14 and 8 months in 2 patients, the sats in the high 80's, both on Aspirin. Before knowing more with follow-up, we plan diagnostic catheters at their pre-Fontan times (circa 2 years of age), and will decide depending on findings. remember that these were done in fairly poor standard Glenn candidates, in the second, even the pulmonary artery anatomy was borderline, in an ex-premature Di George patient who has had multiple atypical infections and chronic lung disease. we don't know what type of veno-venous collateralization may occur to the upper body, if at all, given their poor upper body venous anatomy which made us do this operation in the first place. to give this concept a true shot, i believe we should try it in patients with normal upper body venous anatomy, good PA size with low pressures, and see what happens. pulmonary blood flow and saturations, or the need for a takedown have not been issues in our 2 patients with bad anatomy, so i wonder how the circulation would behave in a patient who would be a good standard bidirectional Glenn candidate: 1. if we give them "hepatic factor" from the beginning, and they don't develop pulmonary AV malformations, nor veno-venous pop-offs to the upper body, should we do a completion Fontan? 2. if faced with an older child with saturations of 88-89% with good cardiac output and no intra-pulmonary shunts, should we do a completion TCPC (with its inherent problems) just because we want to make the patient pink? the jury is out...

Congratulations, Ali & Jorge. Your smart technique allows unsuitable children for a Glenn procedure to be rescued towards the univentricular pathway. Interestingly, the so-called "hepatic factor" might be present so far. On the other hand, who knows whether this will become the "definite palliation" in this subset of children, should a superior cavo-pulmonary anastomoses is ruled out. Brilliant!

By the way, would you consider to keep the azygos vein patent, in order to mimic a sort of "reversed Kawashima"? Best regards.

thank you Juan-Miguel for your kind comments and question, very good to hear from you. we have debated leaving a fenestration in the circulation, most realistically with an interposition graft between the IVC-PA conduit and the common atrium in the next patient, with mixed feelings: i believe it would steal blood away from the lungs, perhaps hinder PA growth potential, and lead to failure of the circulation, while Jorge correctly sees it as a pop-off in case our patients get into trouble. technically, i don't think leaving the azygos vein open is feasible, as it needs to be divided so that you can mobilize the SVC out of the way, so that the IVC-PA conduit can fit (in 3-D, the IVC-PA anastomosis actually lies posterior to the skeletonized SVC). more experience needs to be gained, ideally with comparable patients in both groups with or without a "fenestration", before we know which way to go - hopefully we'll hear from you and others what your experience is.

Follow-up: after an initial very satisfactory one-and-a-half years post-"upside down" or "Southern" Glenn with regards to saturations and thriving, our patient started developing cyanosis. A cardiac catheter was done, revealing a large veno-venous collateral between the IVC and the SVC, which had since grown to normal proportions (the initial alternative surgery had been chosen due to a very small SVC with a thrombosed innominate vein), and what seemed like stenosis at the junction of the extracardiac IVC-LPA. The collateral was plugged with a device, and the LPA ballooned. After initial improvement, the cyanosis persisted. The child was taken to surgery, the large SVC confirmed, the IVC-PA conduit opened to reveal an important intimal peel reducing the effective diameter of the conduit by half, with a narrowed true lumen and false lumen impinging on the takeoff of the LPA, thereby explaining the cyanosis and veno-venous collateral. The extant bovine pericardial extracardiac conduit was fully excised, replaced with an 18mm Goretex from IVC-PA in the same fashion as an extracardiac Fontan, and the enlarged SVC connected to the PA ("Northern" Glenn) to complete total cavo-pulmonary connection. Given the child's somewhat younger age (21 months), a fenestration was added. The child had an easy post-operative course, and was discharged home in good condition. Lessons learned: 1. Bovine pericardium is probably not the best choice in a low pressure system, despite prophylactic Aspirin (or it needs increased anticoagulation). It can develop a problematic intra-luminal peel which reduces effective (pulmonary) blood flow. 2. After a primary extracardiac IVC-PA conduit performed under conditions of suboptimal upper body systemic venous anatomy, the SVC can grow to normal size, probably through forced flow and path of least resistance, thereby setting up a situation where a standard Fontan completion may be done, by doing a "Northern" Glenn. 2. a stand