Imaging-Guided Vessel Sizing in the Tibial Arteries

Study Overview
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Brief Summary
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This study aims to investigate the utilization of intravascular imaging in treatment of tibial vessels in peripheral artery disease and critical limb ischemia (CLI). The primary goal is to compare optical coherence tomography (OCT) with traditional digital subtraction angiography (DSA) in determining best treatment strategy and vessel optimization, in an effort to improve long term patency and successful wound healing in CLI. Secondary comparison with intravascular ultrasound (IVUS) is undertaken when clinically feasible. The hypothesis is that the adjunctive use of intravascular imaging will affect vessel sizing and anticipated treatment modalities, and therein affect the long term primary patency rates.

Detailed Description
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This is a prospective, nonrandomized trial to investigate the adjunctive use of intravascular imaging in tibial vessel interventions. The evaluation of OCT is primarily to: (a) establish feasibility and reproducibility in below-the-knee vessels, (b) determine the optimal protocol imaging to produce the optimal clear image frame and clear image length, (c) provide detailed lesion characteristics of tibial disease, (d) assess for luminal gain post-intervention. Operator-determined sizing will be compared against University Hospitals Core Imaging Laboratory assessment of OCT, IVUS (when applicable), and quantitative vessel analysis (QVA). Subjects will follow up per routine care with corresponding ankle-brachial index and toe-brachial index at 1, 3, 6, and 12 months or as clinically indicated. Wound and amputation data will be collected at the pre-procedural visit and with each subsequent visit. Wound care will be managed by our wound care associates in podiatry, vascular medicine, vascular surgery, or plastic surgery.

Official Title
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Imaging-Guided Vessel Sizing in the Tibial Arteries

Conditions
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Peripheral Artery Disease, Critical Limb Ischemia

Intervention / Treatment
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* Diagnostic Test: Digital Subtraction Angiography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >18 Patients with presence of Rutherford IV-VI Presence of ≥1 tibial artery involvement requiring endovascular treatment Exclusion Criteria: Patients who do not have tibial disease appropriate for intervention Estimated glomerular filtration rate <30 mL/min not on hemodialysis

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Tibial Vessel Involvement in Patients with peripheral artery disease and CLI<br>The primary goal is to establish a protocol for performing optimal OCT in below-the-knee vessels. OCT images will be analyzed for lesion characteristics, lesion sizing pre- and post-intervention. This will be analyzed against QVA and IVUS (latter if applicable). | Diagnostic Test: Digital Subtraction Angiography<br>* Compare optical coherence tomography lesion sizing and characteristics compared to traditional digital subtraction angiography<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Standardized Technique for OCT Use in the Lower Limb | To develop a protocolized, reproducible technique to maximize the Clear Image Length (CIL) on 75 mm pullbacks using 100% contrast in the tibial arteries. The goal is to compare intravascular ultrasound (IVUS) and optical coherence tomography (OCT) with traditional digital subtraction angiography (DSA) in determining best treatment strategy and vessel optimization, in an effort to improve long term patency and successful wound healing in CLI. The hypothesis is that the adjunctive use of intravascular imaging will affect vessel sizing and anticipated treatment modalities, and therein affect the long term primary patency rates. | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of Percent Contrast | CIL in 100% contrast versus 50% contrast/heparinized saline mixture | 12 months | 
| Vessel Characteristics: Minimal Lumen Area | minimal lumen area (mm^2) | 12 months | 
| Vessel Characteristics: Reference Vessel Diameter | reference vessel diameter (mm) | 12 months | 
| Vessel Characteristics: Reference Vessel Area | reference vessel area (mm^2) | 12 months | 
| Vessel Characteristics: Percentage Stenosis | percentage stenosis (%) on pre-intervention imaging | 12 months | 
| Plaque Characteristics: Morphology | Percentage composition of calcium, fibrous, or lipid plaque (%) | 12 months | 
| Plaque Characteristics: Calcium Arc | Calcium arc (degree) | 12 months | 
| Plaque Characteristics: Calcium Depth | depth of calcium (micron) | 12 months | 
| Plaque Characteristics: Fibrous cap | depth of fibrous cap (micron) | 12 months | 
| Attenuation | Measurement of attenuation coefficient (μ OCT) to quantify the strength of interaction of light and tissue | 12 months | 
| Vessel Characteristics Following Intervention: Luminal Gain | Post-intervention luminal gain (%), plaque modification, and dissections | 12 months | 
| Vessel Characteristics Following Intervention: Plaque Modification | Reduction in calcium depth (%) if atherectomy is performed | 12 months | 
| Vessel Characteristics Following Intervention: Dissections | Qualitative description of dissections seen on post-intervention imaging | 12 months |