Difficult-to-heal wounds present imbalances in cytokine production, increases in MMP expression, high levels of apoptosis, and decreases in the proliferation of cells such as fibroblasts and keratinocytes, which are involved in tissue regeneration. CRET therapy (capacitive resistive electrical transfer therapy) has been shown to generate granulation tissue in in vitro assays. In addition, available clinical case reports and preliminary clinical trial results indicate that CRET can promote the regeneration of acute wounds and DHW (difficult-to-heal wounds).

Difficult-to-heal wounds present imbalances in cytokine production, increases in MMP expression, high levels of apoptosis, and decreases in the proliferation of cells such as fibroblasts and keratinocytes, which are involved in tissue regeneration. CRET therapy has been shown to be able to generate granulation tissue in in vitro assays. In addition, available clinical case reports and preliminary clinical trial results indicate that CRET can promote acute wound regeneration and CDH.

The working hypothesis is that CRET treatment promotes the healing of CDH through its action in regulating inflammatory and regenerative processes in skin tissue. This non-invasive, cost-effective treatment, devoid of identified adverse effects, and not studied in depth so far in patients with CDH, can thus be placed in the treatment algorithms of CDH with the correct selection of candidate patients.

Inclusion Criteria:

• 18 years of age or older

• Agree to participate in the study and sign the informed consent form.

• Inpatients or outpatients who can be followed by the research team for the duration of the study

• Ulcers with a surface area of no less than 0.5 cm2 and of at least 4 weeks' duration (CDH), located on the lower limbs in the case of ulcers of venous etiology or on the foot, in the case of diabetic foot ulcers.

• For patients with ulcers of venous etiology: ulcers of venous etiology stage 2, 3 4 with diagnosis of chronic venous insufficiency with open wound CEAP IVC C6 according to CEAP classification (38).

• For patients with diabetic foot ulcers presenting:

  • Type 1 and type 2 diabetics with a glycated hemoglobin (HbA1c ≤10% (in a test no longer than 3 months).
  • Patients with UPD without PAD or with associated mild or moderate stage PAD (39) according to the criteria of the intersociety consensus for the treatment of peripheral arterial disease (TASC II).
  • UPD Grade 1A, 1C, 2A, 2C according to the Texas classification (40).
  • Patients who have required previous surgical debridement and 4 weeks have elapsed since such debridement.

• Comorbidity is defined as the presence of at least one of the following criteria:

  • Smoking more than 10 cigarettes per day in the last 6 months.
  • Immunosuppression: systemic treatment with high-dose corticosteroids in the previous 3 months, severe active infection in the previous month, presence of systemic or organ-specific autoimmune disease.
  • Renal failure with creatinine > 2 mg/dl.
  • Respiratory failure with pO2< 90 mm Hg
  • Cardiac failure, grade II or higher
  • Anemia or nutritional deficit
  • Endocrine disruption under medical treatment
  • Neuropathy in the affected area or neurological disease.
  • Connective tissue diseases
  • Mobility impairment
  • Presence of microvascular disease

Exclusion Criteria:

• Pregnancy
• Patients with contraindications for CRET treatments (electronic implants, thrombophlebitis).
• Patients with chronic or pathological wounds that required surgical intervention.
• Ulcers with active infection according to IDSA classification in soft tissues or with clinical and/or radiological signs compatible with osteomyelitis.
• Allergies to standard wound treatment.
• Patients presenting severe renal insufficiency (Glomerular filtration rate ≤30 ml/min in analysis performed in the last 3 months).
• Patient who has presented an acute ischemic event (acute myocardial infarction or stroke, in the 3 months prior to inclusion in the study).
• Patients who present an evolving neoplastic condition, treated by radiotherapy, chemotherapy, hormone therapy or immunosuppressants at the current moment.
• Patients treated for a chronic condition requiring the intake of strong systemic corticosteroids doses ≥ 40 mg prednisone).
• Critical non-revascularizable ischemia or TcPO2 < 25mmHg or a digital hallux systolic pressure < 50 mm Hg in diabetic foot ulcers.
• Patients who do not accept to use the prescribed unloading treatment in the case of diabetic foot ulcers.
• In the case of patients with ulcers of venous etiology, the presence of peripheral arterial disease in any of its stages.
• Patients who do not accept the indicated compressive bandage treatment, in the case of ulcers of venous etiology.