A Early Feasibility Study of the RelayBranch Thoracic Stent-Graft System in Subjects With Thoracic Aortic Pathologies Requiring Treatment Proximal to the Origin of the Innominate Artery

This Early Feasibility Study (EFS) protocol describes the clinical study requirements for the
Relay Branch System; a device designed to provide an option for patients with arch and
proximal descending chronic thoracic aortic pathologies. As an EFS, this investigation is
intended to provide proof of principle and initial clinical safety data on the Relay Branch
System. The study is planned as an initial investigation of the device for aortic arch and
proximal descending thoracic aortic aneurysmal disease, PAU (including IMH) and uncomplicated
chronic Type B aortic dissection (including IMH). The study will yield information on
procedural techniques; assessing the safety and effectiveness of the device at the index
procedure and at 30 days, focusing on device delivery and deployment, and circulatory
exclusion of the pathologic process. As a branched device, patency of the endograft branches
will also be assessed.

The study will evaluate three-dimensional (3D) imaging data, both at baseline and through
follow-up. Baseline 3D anatomy will augment information on the precise anatomic configuration
of patients presenting aortic arch pathology treatable with the device. Follow-up imaging
will provide information on the effectiveness of the device with respect to endoleaks in
patients with aneurysms, sealing of dissections, PAU and IMH, and stability of the device at
the deployed position, response, endograft patency, and short-term device integrity.

The data from this EFS will yield insights into the following aspects of the device,
preceding a traditional feasibility or pivotal study:

- The clinical safety of the device-specific aspects of the procedure,

- Determination of delivery and deployment of the device,

- Operator-dependent aspects of device use,

- Human factors associated with the design and use of the device,

- Safety of the device as assessed by device-related adverse events,

- Effectiveness of the device in performing its intended purpose over short-term
follow-up.

Observations from the study will guide the instructions for use (IFU) for the device.
Finally, the study will collect imaging data to augment the current use conditions data set.
It is anticipated that information collected will be used to make applicable design changes,
or be combined with a prospective, investigational device exemption (IDE) study for
submission of an original premarket approval application (PMA) to the U.S. Food and Drug
Administration (FDA) for approval to commercially distribute the system.

Inclusion Criteria:

Subjects must meet the following criteria to be included in the study:

1. Age ≥18 years

2. Anatomy that would require coverage of the innominate and/or left carotid arteries if
a non-branch endograft were implanted

3. At least one of the following:

a. Aneurysm of the ascending aorta, aortic arch, or proximal descending aorta that
meets at least one of the following: i. ≥ 5.5 cm in diameter ii. ≥ 4.0 cm in diameter
that has increased in size by 0.5 cm in the last 6 months iii. Measures twice the size
of the normal aorta diameter iv. Is saccular in configuration b. PAU within the
ascending aorta, aortic arch, or proximal descending thoracic aorta (DTA) with or
without intramural hematoma (IMH) c. Chronic, uncomplicated type B aortic dissection
or IMH with time from symptom onset to diagnosis ≥ 60 days without malperfusion of the
viscera, kidneys, spinal cord, or lower extremities and with either aortic diameter
≥5.5 cm or ≥4.0 cm with an increase in size by 0.5 cm in the last 6 months

4. A non-aneurysmal proximal aortic neck diameter ranging between 28 mm and 43 mm and a
non-aneurysmal distal aortic neck diameter ranging between 19 mm and 42 mm.

5. A proximal attachment zone of the arch graft proximal to the innominate artery and
distal attachment zone distal to the left subclavian artery.

1. The length of the proximal attachment zone is 30 mm of ascending aorta that meets
the oversizing requirement, plus 10 mm of ascending aorta with a diameter equal
or less than the proximal diameter of the arch graft.

2. The length of the distal attachment zone should be 20mm minimum.

3. Coverage of the left subclavian artery is permitted. Revascularization of the
left subclavian artery may be considered in all cases by the treating physician
and, especially, in anatomies where revascularization is determined to be
clinically necessary

6. The distal landing zone must contain a straight segment (non-tapered, non-reverse
tapered; defined by < 10% diameter change) with length equal to or greater than the
required attachment length of the intended device

7. Non-aneurysmal innominate and left common carotid arteries with diameters ranging
between 7 mm and 20 mm

8. Innominate and left common carotid attachment zone length of 25 mm minimum.

9. Vascular dimensions must be in the range that can be safely treated with the Relay
Branch System

10. Adequate arterial access for introduction and delivery of the Relay Branch System.
Alternative methods to gain proper access can be utilized (e.g., iliac conduit)

11. Considered high risk for conventional surgery by treating physician or aortic team

12. Must be willing to comply with the follow-up evaluation schedule

13. Subject or legally authorized representative must sign the informed consent form prior
to implant.

Exclusion Criteria:

Subjects will be excluded from the study for:

1. Significant stenosis, calcification, thrombus, or tortuosity of intended fixation
sites that would compromise fixation or seal of the device

2. Pre-procedure occlusion or planned coverage of both subclavian arteries

3. Anatomic variants which would compromise circulation to both vertebral arteries after
placement of the stent-graft

4. Prior endovascular repair in the ascending/descending thoracic aorta or aortic arch.
The device may not be placed within any prior endovascular graft

5. Concomitant aneurysm/disease of the abdominal aorta requiring repair

6. Prior abdominal aortic aneurysm repair (endovascular or surgical) that was performed
less than 6 months prior to the planned stent implant procedure

7. Prior aortic valve replacement (mechanical valve)

8. Major surgical or medical procedure within 45 days prior to the planned procedure or
is scheduled for a major surgical or medical procedure within 45 days post
implantation. Except for any planned procedures for the prospective stent-graft
placement, e.g., left subclavian artery bypass or transposition

9. Untreatable allergy or sensitivity to contrast media or device components

10. Blood coagulation disorder or bleeding diathesis in which the treatment cannot be
suspended for one week pre and post repair

11. Coronary artery disease with unstable angina

12. Severe Congestive Heart Failure (CHF)

13. Cerebrovascular accident and/or myocardial infarction within 3 months of the planned
treatment date

14. Pulmonary disease requiring routine (daily or nightly) need for oxygen therapy outside
the hospital setting

15. Acute renal failure or renal insufficiency and not on renal replacement therapy or
dialysis

16. Significant carotid bifurcation disease (>70% diameter reduction by duplex ultrasound
or angiography)

17. Hemodynamic instability

18. Active systemic infection and/or mycotic aneurysms

19. Morbid obesity or other condition that may compromise or prevent the necessary imaging
requirements

20. Connective tissue disorders, mycotic aneurysms, or infected aorta

21. Less than two-year life expectancy

22. Current or planned participation in an investigational drug or device study that has
not completed primary endpoint evaluation

23. Currently pregnant or planning to become pregnant during the course of the study

24. Medical, social, or psychological issues that the Investigator believes may interfere
with treatment or follow-up