The DES BTK Vascular Stent System vs PTA in Subjects With Critical Limb Ischemia

Phase A: A global, prospective, multicenter, 2:1 randomized trial evaluating the safety and
effectiveness of the DES BTK Vascular Stent System compared to standard percutaneous
transluminal angioplasty to treat infrapopliteal artery lesions in subjects with critical
limb ischemia(CLI). Phase A RCT will begin with one size of the device: 3.5 mm x 80 mm.

Phase B: A global, prospective, multicenter, non-randomized trial collecting additional
safety and effectiveness data for the DES BTK Vascular Stent System to treat infrapopliteal
artery lesions in subjects with CLI. Additional stent sizes will be added to the trial upon
regulatory approval.

Approximately 201 subjects will be randomized/enrolled to support a 2:1 randomization in the
phase A RCT. Assuming the effectiveness endpoint is met in phase A RCT, approximately 100
additional subjects are expected to be enrolled in phase B non-randomized which is structured
as a single arm where the enrolled subjects are treated with the DES BTK Vascular Stent
System.

Inclusion Criteria:

1. Subject is 18 years or older and has signed and dated the trial informed consent form
(ICF)

2. Subject is willing and able to comply with the trial testing, procedures and follow-up
schedule

3. Subject has chronic, symptomatic lower limb ischemia, determined by Rutherford
categories 4 or 5

4. Subject is a male or non-pregnant female. If female of child-bearing potential, and if
sexually active must be using, or agree to use, a medically-acceptable method of birth
control as confirmed by the investigator

Intra-procedure Inclusion Criteria:

1. Stenotic, restenotic or occlusive target lesion(s) located in the tibioperoneal trunk,
anterior tibial, posterior tibial and/or peroneal artery(ies).

2. Target lesion must be at least 4cm above the ankle joint

3. A single target lesion per vessel, in up to 2 vessels, in a single limb using the
assigned/randomized therapy

4. Degree of stenosis ≥ 70% by visual angiographic assessment

5. Reference vessel diameter is between 2.5 - 3.75mm

6. Total target lesion length to be treated is ≤ 70mm for phase A RCT prior to the data
monitoring committee's approval for stent overlap

7. Total target lesion length to be treated is ≤ 140 mm for phase A RCT after the data
monitoring committee's approval for stent overlap

8. Total target lesion length to be treated is ≤ 140 mm for phase B non-randomized

9. Target vessel(s) reconstitute(s) at or above the stenting limit zone (4cm above the
ankle joint)

10. Target lesion is located in an area that may be stented without blocking access to
patent main branches

11. Treatment of all above the knee inflow lesion(s) is successful prior to treatment of
the target lesion

12. Guidewire has successfully crossed the target lesion

Exclusion Criteria:

1. Life expectancy ≤ 1year

2. Stroke ≤ 90 days prior to date the subject signed the ICF

3. Prior or planned major amputation in the target limb

4. Previous surgery in the target vessel (including prior ipsilateral crural bypass)

5. Previously implanted stent in the target vessel(s) to be treated

6. Failed PTA of target lesion/vessel ≤ 60 days prior to date the subject signed the ICF

7. Renal failure as measured by a GFR ≤ 30ml/min per 1.73m2, measured ≤ 30 days prior to
the procedure date

8. Subject has a platelet count ≤ 50 or ≥ 600 X 103/µL less than or equal to 30 days
prior to the procedure date

9. NYHA class IV heart failure

10. Subject has symptomatic coronary artery disease (ie, unstable angina)

11. History of myocardial infarction or thrombolysis ≤ 90 days prior to date the subject
signed the ICF

12. Non-atherosclerotic disease resulting in occlusion (eg, embolism, Buerger's disease,
vasculitis)

13. Subject is currently taking Canagliflozin

14. Body Mass Index (BMI) <18

15. Active septicemia or bacteremia

16. Coagulation disorder, including hypercoagulability

17. Contraindication to anticoagulation or antiplatelet therapy

18. Known allergies to stent or stent components

19. Known allergy to contrast media that cannot be adequately pre-medicated prior to the
interventional procedure

20. Known hypersensitivity to heparin

21. Subject is on a high dose of steroids or is on immunosuppressive therapy

22. Subject is currently participating, or plans to participate in, another
investigational trial that may confound the results of this trial (unless written
approval is received from the Boston Scientific study team)

Intra-procedure Exclusion Criteria

1. Angiographic evidence of intra-arterial acute/subacute thrombus or presence of
atheroembolism

2. Treatment requires the use of alternate therapy in the target vessel(s)/lesion(s),
(eg, atherectomy, cutting balloon, re-entry devices, laser, radiation therapy)

3. Aneurysm is present in the target vessel(s)

4. Extremely calcified lesions