All commercially available stent grafts perform generally well in a great variety of anatomies.1 Nevertheless, there are still important differences in delivery systems and device designs, which call for tailormade graft selection according to patients' specific anatomy and physicians' personal experiences.2,3

The GORE® EXCLUDER® Device (Gore & Associates, Flagstaff, AZ) is a thirdgeneration device that has now been used for 15 years in more than 159,000 patients with proven safety, efficacy, and long-term durability.4-8 Beneficial characteristics of the device include a low profile delivery catheter that is advantageous in narrow and tortuous iliac anatomies and a simple and rapid deployment mechanism.6 A number of design improvements have been made over the years, with the most notable involving the addition of an expanded polytetrafluoroethylene layer to reduce porosity and serous fluid transmigration.9,10

In 2010, Gore revised the GORE® EXCLUDER® Device delivery system to enable the user to achieve a more precise and controlled deployment. The GORE® C3® Delivery System allows the device to be repositioned twice before final deployment. The performance of the GORE® C3® Delivery System is currently being investigated in the Global Registry for Endovascular Aortic Treatment (GREAT). This article presents the options offered with the GORE® C3® Delivery System deployment mechanism and discusses the lessons learned from real-world experience as reflected in the preliminary outcomes of the GREAT registry.

GORE® C3® DELIVERY SYSTEM DEPLOYMENT MECHANISM

The deployment mechanism has been modified into a three-step sequence, which enables repositioning of the device up to two times prior to final release from the delivery catheter.11 In the first step, the trunk and contralateral leg are opened (Figure 1A). A constraining loop around the proximal trunk of the graft enables recapturing and repositioning of the stent graft for both level and orientation (Figure 1B). The second step involves the removal of the reconstraining system after confirmation of correct positioning (Figure 1C). The third step involves the deployment of the ipsilateral leg (Figure 1D).

Deployment Options

The concept of the GORE® C3® Delivery System enables readjustments of the GORE® EXCLUDER® Device for proximal level, orientation, and distal level of the ipsilateral leg. The main feature is the ability to reposition the device for the proximal level, enabling precise deployment with regard to the renal arteries. This can be advantageous both for inexperienced users (second and third chance for deployment at the correct level), but also for experienced users in more difficult proximal anatomies.

The deployment mechanism also offers the option for rotational readjustment. In cases of challenging contralateral gate cannulation, the proximal trunk can be reconstrained and the gate reoriented to a more convenient location for catheterization. The separate deployment of the ipsilateral leg allows for adaptation of the leg length. All this resulted in a deployment sequence in which all of the options can be used (without saying that one has to use all the options) (see Deployment Sequence sidebar).

THE GREAT REGISTRY

The GREAT registry was initiated in an attempt to identify global trends in device usage and to actively track long-term device performance and patient outcomes. GREAT aims to collect patient and device performance outcomes during treatment and throughout all posttreatment visits, including follow-up extending up to 10 years for patients treated with GORE® endovascular aortic products.

Commercial aortic endovascular products used in global markets (e.g., US, EU, Australia, Brazil, and China) are being evaluated with 10 years of follow-up in 5,000 patients from up to 300 sites worldwide. Data originating from both on-label and off-label use of the devices are collected through an internet-based system. Evaluated data consist of patient demographics and medical history, treatment indication, case planning and device used, operative details, and posttreatment follow-up to 10 years, including documentation of any serious adverse event. Additional data are also collected in case of modified device usage.

One of the modules of the GREAT registry collects and analyzes data regarding use of the GORE® C3® Delivery System in Europe. By the end of December 2012, 400 patients (86.8% men; mean age, 73.9 ± 7.8 years) from 13 European sites were enrolled in the registry by meeting the enrollment goal. Elective abdominal aortic aneurysm was the most common indication for treatment (94.5%) followed by common iliac artery aneurysm (3%), ruptured abdominal aortic aneurysm (1.5%), and other indications (1.1%). In 98.2% of the cases, device implantation was performed as a primary procedure, while the remaining cases concerned reinterventions after prior open- or endovascular aortic procedures. Challenging anatomy including short proximal neck (< 1.5 cm) and/or neck angulation > 60°, was present in 16.5% of the patients.

Operative mortality was 0%. Two patients (0.5%) required open conversion—one due to arterial rupture and the other due to stent graft deployment at the wrong position. Proximal trunk repositioning was performed in 47.6% of the cases, most frequently for level readjustment with regard to the renal arteries (79.5%) and less commonly (19.5%) for contralateral gate reorientation. Other less frequently reported reasons for repositioning included uncovering the renal arteries, intentional deployment above the renal arteries, intentionally twisting limbs for better position, and repositioning to facilitate renal chimney stent placement. The mean number of repositionings performed per case was 1.4 ± 0.7. One repositioning was required in 64.7%, two in 27.4%, three in 6.3%, and four in 1.6% of cases.* Exact positioning was achieved in 96.2% of patients, with 97.7% within 5 mm of the intended location. Unintentional use of proximal extender cuffs occurred in 4.5% of the patients.

Survival at 30 days was 99.5%. Two patients died—one of respiratory failure and the other due to cardiac failure. Type I endoleak within 30 days after the procedure was detected in one patient (0.25%). Device migration was not seen in any of the patients. A more extensive report and analysis of the GREAT registry outcomes with regard to the GORE® C3® Delivery System is beyond the scope of the present article.

LESSONS LEARNED FROM REAL-WORLD EXPERIENCE

The main reason for redesigning the GORE® EXCLUDER® Device deployment mechanism was to enable more accurate proximal deployment. This goal has been achieved with the GORE® C3® Delivery System. Current real-world outcomes suggest that repositioning for optimizing proximal landing is safe and feasible, with a more accurate deployment to start with. Occasionally, problems can arise, for example, in the case of low initial deployment in narrow or angulated neck anatomy with cumbersome upward repositioning of the device. This is partially due to the fact that there is only one proximal constraining loop, which reduces the proximal diameter of the device, but the rest of the distal stent graft remains unconstrained. In such cases, first deployment of the device as close as possible to the renals and then meticulous lower repositioning, as needed, should be considered.

Similarly, extensive or abusive rotational reorientation may cause a twist in the ipsilateral leg, requiring additional stenting for correction (Figure 2). Such a limb twist can easily be recognized during slow deployment under fluoroscopy and then corrected. Caution should also be observed not to lose proximal position during rotational repositioning, especially in narrow or angulated neck anatomy, as previously mentioned.

CONCLUSION

Early real-world experience shows that the GORE® C3® Delivery System offers important advantages in terms of device repositioning. Level and orientation repositioning can be useful. Additionally, the deployment system enables new alternative deployment sequences that should be considered in cases of difficult contralateral gate cannulation (reorientation) or relining after previous endovascular aortic repair. Not all of these options will be used in each and every patient, but physicians should be aware of these selections. The GORE® C3® Delivery System is safe, but abuse of the features may carry new risks in some situations.

Eric L.G. Verhoeven, MD, PhD, is Chief, Department of Vascular Surgery, Klinikum Nürnberg Süd in Nürnberg, Germany. He has disclosed that he is a consultant to and has received educational grants from Cook, Gore, and Atrium Maquet and is a consultant to Siemens. Dr. Verhoeven may be reached at +49-9113982650; eric.verhoeven@ klinikum-nuernberg.de.

Athanasios Katsargyris, MD, is with the Department of Vascular and Endovascular Surgery, Klinikum Nürnberg Süd in Nürnberg, Germany. He has disclosed that he has no financial interests related to this article.

Ross Milner, MD, is Associate Professor of Surgery, Co-Director, Center for Aortic Diseases, and Associate Program Director, Vascular Surgery Fellowship at the University of Chicago Medical Center in Chicago, Illinois. He has disclosed that he is a consultant to Gore.

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