Early Percutaneous Transluminal Angioplasty in Diabetic Foot Syndrome (PTA-DFS)

Study Overview
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Brief Summary
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The planned study is a Randomized Controlled Monocentric Trial, which will provide evidence on whether early angiography in PTA readiness (immediate treatment, within 48h) has advantages over the standard of care, i.e., an elective procedure (elective PTA) in terms of clinical endpoints such as wound healing and infection according to WiFI classification, amputation rate, major adverse limb events (MALE=amputation, reintervention of the vessel, death), but also systemic complications such as major adverse cardiac and cerebrovascular events (MACE=myocardial infarction, stroke, death, restenosis, severe cardiac and cerebrovascular complications). Furthermore, the impact of PTA on the local wound microbiome remains unclear. Altered microbiome composition in ulcers can lead to severe local and systemic infections and complications, including major amputations. Nevertheless, the specific significance of the wound microbiome composition in chronic ischemic ulcers in type 2 diabetes and the impact of PTA on the wound microbiome in type 2 diabetes is unclear. The exact timing for treating pAVD by revascularization in DFS after initial diagnosis is unknown and has yet to be fully understood.

Detailed Description
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The planned study is a monocentric, randomized and controlled clinical trial. Study participants will be randomized in a 1:1 ratio into a group with early PTA (immediate PTA, within 48h) and a group with elective PTA (standard of care). Baseline and all follow-up examinations will be performed identically in both groups except for PTA. The study is unblinded to the patients and physicians, i. e., the investigators do not plan a control intervention for PTA. However, all subsequent laboratory tests, especially the measurement of biomarkers of inflammation, are designed to be blinded, i. e., without passing information on PTA to the laboratory. Baseline and follow-up examinations will focus on the severity and healing process of the foot ulcer. If patients in the elective arm experience a significant deterioration in wound healing, they are crossed to the immediate arm. Thus, for each of our patients, the treatment of pAVD follows the guidelines, which are controlled and documented by specialists in the clinical progress controls and visits during the study. During the visits, the investigators do not only pay attention to the diabetic foot ulcers but see each patient as a critically ill patient in the overall picture. Thus, the investigator first tried to improve renal retention parameters by sufficient hydration, considering cardiac function. In severe renal insufficiency, guideline-based selective angiography on PTA standby using CO2 angiography is possible, which does not affect the kidney. Baseline characterization The patient's complete medical history and current and previous medications are obtained during the initial clinical evaluation. In addition to the medical record, lifestyle questions (smoking, alcohol) and social status are elicited (marital status, educational attainment/social status). A physical examination is performed, which includes determining whether venous or neuropathic triggers should be considered in addition to the ischemic etiology of the ulcers. For evidence of chronic venous insufficiency (CVI), the investigators will perform duplex sonography of the peripheral leg veins. If there is evidence of chronic venous insufficiency, the severity will be evaluated using the Clinical (C), Etiological (E), Anatomical (A), and Pathophysiological (P) (CEAP) classification. Routine laboratory chemistry testing will also be performed using blood samples. In addition, the diabetes mellitus duration will be recorded. Wound documentation Wound documentation is performed to document existing ulcerations. The affected areas, their depth, and volume will be recorded. This photo documentation should always be carried out at the same angle, in the same position and distance, and under the same lighting conditions as far as possible. The wound is assessed according to the WIfI and Wagner (Armstrong) classification criteria recommended by current interdisciplinary guidelines. Perfusion measurement The following examinations are performed: Duplex/Doppler ultrasound of the leg arteries with Doppler frequency analysis and ankle-brachial and toe-ankle index measurement. In the subsequent duplex ultrasound, the anatomy of the peripheral arteries is defined. Later in the course, these examinations determine the patency of the revascularized vessel segment, degree of stenosis by peak flow velocity determination and intimal hyperplasia. Furthermore, flow-dependent dilatation of the femoral artery is also examined using duplex sonography. Oxygen saturation of the foot will be analyzed using a spectroscopic camera; its control measurement is done by measuring the hands. Segmental pulsoscillography Measurement of arterial perfusion at rest and perfusion reserve using occlusion plethysmography. Hemodynamics (blood pressure and heart rate) Pain at rest. Recording of current clinical symptoms and pain questionnaire according to McGill. Peripheral neuropathy will be within the scope of the study; the participating patients will also be examined for peripheral polyneuropathy, based on the National Health Care Guideline (NVL) Neuropathy in Diabetes in Adulthood. Peripheral nerve function tests include the clinical neuropathy score survey to diagnose diabetic sensorimotor polyneuropathy (DSNP). In detail, the neuropathy symptom score (NSS) and the neuropathy deficit score (NDS) are recorded. Swab wound Specimen collection is performed according to the Levine method using a commercially available flocked swab (FLOQSwab®, COPAN Diagnostics Inc, Murrieta USA). A total of 3 swabs will be taken from each patient in the project at the same time to obtain material for determining the microbiome and the corresponding resistogram (specific transport media will be used depending on the downstream process). Swabs are collected after thorough wound cleansing, the first after initial wound care, the second at four weeks, the third at eight weeks, the fourth at 12 weeks, the fifth at 24 weeks, and the last at 48 weeks. Measurements of phylogenetic composition based on the wound samples at baseline will determine the different bacterial species in the wound samples using whole genome sequencing in collaboration with the Institute of Medical Microbiology and Hospital Hygiene at Heinrich Heine University, Düsseldorf. The microbiome's composition is studied using nanopore technology, which has several advantages. Data are analyzed using custom bioinformatics scripts. Blood collection will be performed in the morning on an empty stomach. Blood collections are performed i.d. in a clinical routine before PTA and during the follow-up visits of the DFS and do not represent a study-related collection. On this occasion, additional blood samples can be taken without additional study-related punctures. Blood will be collected in so-called stretch tubs for testing for cell-free (cf)DNA. The time points include routine follow-up examinations on the first day of examination (V0), on day 1 (V1), one month (V2), two months (V3), three months (V4), six months (V5), 12 months (V6) after PTA. Over the study's duration, less than 500 ml of blood should be drawn per patient. Examination of cfDNA To assess the incorporation of microbial components from the revascularized tissues, the investigators would like to determine the amount of microbial cfDNA. A sufficient amount of the collected material will be assayed for a maximum period of three years. Statistical analysis Taxonomic profiling of whole-genome sequencing data of the wound microbiome is performed using bioinformatics scripts from the Department of Algorithmic Bioinformatics at HHU, as previously described. Whole-genome sequencing data of the wound microbiome generated with the Oxford Nanopore platform will be used for taxonomic profiling with Kraken2 and a comprehensive custom database of protozoan, fungal, viral, and plant sequences. Visualizations that allow comparison of metagenomic composition at different taxonomic levels are generated using custom scripts. To evaluate the clustering of samples, the investigators performed a principal coordinate analysis based on the Bray-Curtis distance. Using the Conda version management system, the entire workflow is provided as a reproducible Snakemake workflow. Association of wound microbiome composition with metabolic phenotypes will be performed using omnibus, blockwise, and traitwise statistical models. Variables will be compared using the Wilcoxon matched-pairs signed rank test, the unpaired two-sided Student t-test, and the two-sided Mann-Whitney U-test to detect differences over time and between groups. Nominal variables are compared using the chi-square test and Fisher's exact test, as appropriate. Relationships between variables (e.g., associations between changes in microbiome composition and wound healing or complications) will be assessed using partial Pearson correlation coefficients (with and without adjustment for confounders and multiple testing using the Bonferroni method). Standardized mean difference (Cohen's d) was used for power analyses because preliminary estimates for the mean and standard error of the mean of wound microbiome change after PTA were not available in the literature. All statistical analyses are performed using SPSS for Windows 23.0 (SPSS Inc., Chicago, IL, USA). All graphs are generated using GraphPad Prism, version 7.01 (GraphPad Software, Inc., La Jolla, CA, USA).

Official Title
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Role of Percutaneous Transluminal Angioplasty for Wound Healing and Dynamics of the Microbial Community in Patients With Type 2 Diabetes and Diabetic Foot Syndrome

Conditions
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Anemia, Diabetic Foot, Diabetes Mellitus, Peripheral Arterial Disease, Diabetic Neuropathies, Diabetic Retinopathy, Ulcer Foot, Ulcer Ischemic, Diabetic Polyneuropathy

Intervention / Treatment
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* Procedure: percutaneous transluminal angioplasty


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: volunteer adults written informed consent presence of known manifest T2D and fulfilment of the following criteria: HbA1c < 10% presence of pAVD with fulfillment of the following criteria: PAD Stage After Fontaine IV (foot ulcer) Presence of foot ulcer with fulfillment of the following criteria: Foot ulceration without indication for emergency surgical care (No sepsis, osteomyelitis) from stage Wagner 1. Age between 18 and 70 years BMI 20 - 45 kg/m2 Exclusion Criteria: Acute leg ischemia (sudden onset, sensorimotor deficits, pale extremity, pain, loss of pulse, and shock). Type 1 diabetes mellitus (GADA, ICA, IA-2A, ZnT8A positive). Minors or subjects incapable of giving consent Pregnant or breastfeeding women Treatment with certain drugs (immunosuppressive therapy, Immunomodulators, chemotherapy, antibiotic therapy < 2 weeks before intervention) Diseases of the pancreas Severe neurological or psychiatric disease Known presence of malignant tumor disease within the past 5 years Participation in other interventional trials and receipt of investigational medication within the last 30 days Blood or plasma donation within the last 3 months

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: immediate PTA<br>study participant in this group will receive a PTA in ''readiness'', that means 48h after the initial study examination. | Procedure: percutaneous transluminal angioplasty<br>* percutaneous transluminal angioplasty<br>|
| Active Comparator: elective PTA<br>A study participant in this group will receive a PTA according to the hospital's standard of care, that means 3 weeks after the initial study examination | Procedure: percutaneous transluminal angioplasty<br>* percutaneous transluminal angioplasty<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| effect of an immediate (within first 48h) PTA intervention on microbiome composition | assessed by whole-genome sequencing techniques) in diabetic foot ulcera compared to an elective (Standard of Care group) PTA intervention. | Baseline to one year follow up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the effect of the immediate PTA intervention on overall wound-healing | assessed by image-based artificial intelligence in wound assessment tools) in diabetic foot ulcera compared to an elective PTA intervention | Baseline to one year follow up | 
| Effect of the immediate PTA intervention on microcircularion | assessed by multispectral near-infrared spectroscopy | Baseline to one year follow up | 
| Effect of the immediate PTA intervention on related complications | defined as infections/progress of ulcera, MACE and MALE (compared to an elective PTA) | Baseline to one year follow up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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diabetic foot syndrome, peripheral artery disease, diabetic food ulcers, microbiome, percutaneous transluminal angioplasty