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Commentary: The Zenith t-Branch Endograft

The introduction of multibranched endografts (mbEVAR) for total endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) provided a less invasive therapeutic option in the armamentarium of vascular surgeons, avoiding wide surgical exposure, aortic clamping, and visceral ischemia. The technique showed excellent early performance, and there is now long-term data confirming its durability. Despite this success, there is still a major issue that impedes the applicability of the technique in all TAAA patients: the custom-made design. The custom-made design fits perfectly to the anatomy of the patient, but this presupposes a relevant delay in manufacturing (up to 8 weeks). Hence, a considerable number of “urgent” patients (extensive asymptomatic, symptomatic, or ruptured TAAAs) are mostly excluded from this treatment option or receive alternative endovascular and hybrid techniques, with still controversial and not well-proven efficacy. Six years ago, the San Francisco group suggested a standard design for a multibranched endograft applicable to the majority of patients with any type of TAAA. Based on this platform, the first off-the-shelf 4-branched endograft, the Zenith t-Branch endograft (Cook Medical, Bloomington, IN, USA), was born. The device is designed with 4 downward facing branches and comes loaded in a 22-F sheath. (The low-profile 18-F device is still not available for use in Europe.) The stent-graft has a 34-mm proximal diameter tapering to 18 mm distally over a 202-mm-long body. The branches for the superior mesenteric artery (SMA) and celiac artery are 8 mm wide and 18 and 21 mm long, respectively. The renal side branches measure 6 mm across by 18 mm long. The orientation of the branches is at 01:00, 12:00, 10:00, and 03:00 o’clock for the celiac trunk, SMA, and right and the renal branches, respectively. Figure 1A provides an overview of the important markers on the device for fluoroscopic visualization. The anatomic selection criteria for the t-Branch have been described extensively elsewhere. Based on these criteria, 2 different groups, one in the United States (San Francisco) and our group in Europe (Münster, Germany), assessed the applicability of the device in patients already treated for TAAA by using custom-made endografts. The suitability of the t-Branch amounted to 54% and 49%, respectively; adding different adjuvant measures, that is, proximal thoracic endografting, carotid-subclavian bypass, and so on, elevated the suitability to 83%. Such a rate confirms the off-the-shelf applicability of the endograft. On the other hand, the technical success and clinical performance of this endograft were also assessed in daily practice. The early (30-day) results published by our group showed a 100% technical success rate without any organ ischemia or renal function deterioration; 30-day mortality was 0. However, the greater challenge for this new device was in a comparison of its efficacy to the ideal 4-branched custom-made endografts for the same indication. In that study, the t-Branch endograft revealed comparable clinical outcomes to the traditional custom-made endoprosthesis: the survival rates at 6 months were 94% and 71%, respectively. Paraplegia remained very low in both groups (5% vs 4%, respectively), and the freedom from reintervention was comparable as well (90% vs 100%, respectively), though a trend to higher renal branch occlusion rates was observed in the t-Branch group. In two patients, a thrombophilic disorder was identified, and in one patient the aneurysm remodeling due to sac shrinkage led to a dislocation of the bridging endograft, with subsequent branch occlusion. At present, it seems that the t-Branch has fairly taken its place among the endovascular therapeutic options for TAAAs, but further surveillance remains mandatory. 618471 JETXXX10.1177/1526602815618471Journal of Endovascular TherapyBisdas and Austermann research-article2015