Today, in our “Scrub with the Experts” section, we are delighted to offer our audience an interview with Dr. Sukgu Han. Dr. Han is Chief of Division of Vascular Surgery and Endovascular Therapy Program in Keck Medicine of USC. He is also Professor of Surgery and Neurological Surgery at the University of Southern California, and Program Director of Vascular Surgery Residency and Fellowship at USC.
Dr. Han has extensive experience in the modification of endografts for the aortic arch and thoracoabdominal aorta, utilizing both fenestrations and branches with several related publications. He holds a physician sponsored investigational device exemption protocol for PMEG.
Javier Río: First, thank you very much, Dr. Han, for your collaboration, and welcome to our platform. Let’s start from the beginning: What motivated you to start using PMEGs (physician-modified endografts)? In the United States, this technique seems to be used quite frequently, as evidenced by various publications. Why do you think this is the case in a country with high purchasing power?
Sukgu Han: Thank you for having me, Dr. Río. I’ve been following your innovative content for some time, and it’s an honor to contribute.
I began performing PMEGs about 10 years ago to address urgent cases where commercially available devices, like ZFEN, were not suitable. I followed the examples set by early adopters of PMEGs, who generally used similar indications.
Initially, PMEGs operated "in the shadows" due to concerns over liability and reimbursement, given their off-label status and the perception by some that they were illegal in the U.S. without an investigational device exemption (IDE). This limited the ability to publish results and share lessons, as only a minority of centers performing PMEGs had IDE approval. Despite these challenges, PMEGs addressed a critical unmet need, and their adoption spread widely, aided by the growing number of surgeons trained in these techniques. This trend is well-documented in a recent VQI publication by Dr. Hicks and colleagues.
Device cost has only recently become a significant factor with the introduction of FDA-approved four-vessel devices like GORE TAMBE. TAMBE’s off-the-shelf inner branch design offers a robust solution but comes at a higher cost than modified base endografts. While TAMBE adoption is growing rapidly, including at our center, some physicians have reported cost constraints limiting its use, with PMEGs remaining an alternative for anatomies amenable to its repair.
J.R.: Recently, a multicenter registry with favorable mid-term results for this technique was published in the prestigious Circulation journal. This could encourage physicians to adopt the technique. In your opinion, what type of patient or anatomy benefits the most from this technique in the thoracoabdominal aorta?
S.H.: The key advantage of PMEGs lies in their rapid accessibility and versatility, providing custom solutions for patients with complex anatomy. In my experience, PMEG is an excellent option for symptomatic patients with large aneurysms and challenging anatomy who are not candidates for manufactured devices like TAMBE. This includes cases with chronic dissections, large accessory renal arteries, or aberrant visceral anatomy.
We were fortunate to contribute to the multicenter PMEG study led by Drs. Nikolais Tsilimparis and Gustavo Oderich, and we are now working on secondary analyses to address questions like yours. Stay tuned for more details in upcoming meetings and publications!
J.R.: Based on your published experience, you have achieved good results using inner/external branches in PMEGs. Many centers, including that of the interviewer, limit themselves to fenestrations, considering them less technically demanding. What is your opinion regarding inner/external branches? Are they more challenging to construct? Are they more prone to leaks?
S.H.: Directional branches are excellent options for PMEGs in cases where reinforced fenestrations would likely result in significant gap distances, which have been linked to increased target vessel instability. Constructing them is not particularly challenging, and I don’t believe they are more prone to leaks compared to fenestrations. In fact, they may be more effective in patients with significant gap distances.
Over the years, I’ve found inner branches especially valuable to incorporate into PMEG designs. For anyone interested in adopting inner branches in their PMEG practice, I’d be happy to share our previous publications and my recent presentation at CASO.
J.R.: In your daily practice, what is your favorite endograft to modify? What advantages does it offer over others?
S.H: For the past 10 years, our go-to endograft has been the Cook Alpha Thoracic. Its multiple trigger wires allow for a temporary diameter reduction system in the thoracoabdominal aorta, and the self-orienting spine wire is particularly useful in the arch.
Recently, we’ve adopted the Terumo TREO for pararenal AAAs, using it as a fenestrated bifurcated construct. Compared to combining TEVAR and EVAR devices, this design offers less device overlap and significantly lower costs.
J.R.: If you could change any feature of the current endografts to make them easier to modify, what would it be?
S.H.: Some of the key changes that I would make, include a dedicated fenestration ring, a side-arm branch component, and an improved mechanism for easier re-sheathing. I believe Terumo Aortic is actively addressing these enhancements as part of the multicenter 'TREO FIT' IDE program, with Dr. Benjamin Starnes serving as the national principal investigator.
J.R.: Regarding treatment of the aortic arch, you have published fascinating work on branched PMEGs, in which you highlight a significant learning curve. What tips or tricks can you share for those starting in aortic arch treatment to achieve good outcomes?
S.H.: The incorporation of a self-orienting spine trigger wire, enabling anatomically specific inner branch construction, has been pivotal in revitalizing our arch PMEG program. This innovation allowed for precise deployment, aligning inner branches with target vessels and facilitating branch cannulation with minimal wire manipulation. As a result, we observed a 50% reduction in fluoroscopy time, which I believe significantly improved our outcomes. I owe much of this success to Dr. Carlos Timaran, who generously shared many of these technical insights with me.
J.R.: To conclude: Do you think we are close to having one (or several) endografts with Instructions for Use that explicitly include physician modification?
S.H.: The device closest to achieving this goal is the Terumo TREO, currently being evaluated through the TREO FIT program in its trial phase. However, I have not observed similar advancements for the thoracoabdominal or arch regions, which likely still have a longer way to go.
Thank you very much, Dr. Han, for sharing your outstanding experience and valuable insights with us all.
It's my pleasure, and I hope we get the chance to meet in person someday!
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