Contrast-induced nephropathy (CIN) is a common complication in high-risk patients undergoing percutaneous coronary intervention (PCI) due to exposure to iodinated contrast agents. CIN is associated with increased morbidity, prolonged hospital stays, and higher healthcare costs. Current preventive strategies include adequate hydration and minimizing contrast volume; however, there is no universally effective pharmacological intervention.

Recent studies suggest that inorganic nitrates can enhance renal perfusion, reduce oxidative stress, and improve endothelial function, potentially lowering the risk of CIN. This study aims to evaluate the efficacy and safety of a beet-derived inorganic nitrate-based food product for the prevention of CIN in high-risk patients undergoing PCI.

This is a randomized, controlled, open-label clinical trial comparing two groups:

1. Intervention Group: Patients receiving the beet-derived inorganic nitrate-based food product for 5 days (starting 24 hours before PCI).
2. Control Group: Patients receiving standard medical care without additional nitrate supplementation.

We hypothesize that the nitrate-based food product will significantly reduce the incidence of CIN compared to standard care. Additionally, we expect:

1. A lower increase in kidney injury biomarkers (NGAL, cystatin C) in the intervention group.
2. A slower decline or even improvement in eGFR at follow-up.
3. A potential reduction in MACE due to the vasoprotective effects of nitrates.
4. Improved quality of life scores (EQ-5D) in the intervention group. If successful, this study will provide new evidence supporting the use of dietary nitrates for renal protection and may contribute to the development of novel, cost-effective prevention strategies for CIN.

Inclusion Criteria:

• Age ≥18 years.

• Planned PCI.

• High risk of CIN with:

  1. eGFR according to the CKD-EPI formula <60 ml/min/1.73 m2 or
  2. At least two of the following criteria: liver damage (cirrhosis), diabetes mellitus, age >70 years, administration of contrast in the last 7 days, CHF (LVEF >40%), intake of drugs affecting renal function (ACE inhibitors, ARBs, NSAIDs, aminoglycosides, diuretics).

• Signing informed consent.

Exclusion Criteria:

• Allergy to nitrates.
• Acute coronary syndrome.
• Acute condition accompanied by systolic blood pressure <90 mmHg for more th an 30 minutes or requiring the use of drugs with a positive inotropic effect.
• Life-threatening conditions requiring emergency medical care.
• Participation in other clinical trials.
• Pregnancy, lactation.
• Use of nitrates in the last 30 days.
• Abuse of alcohol, illegal drugs, mnestic-intellectual decline, as well as other reasons and circumstances indicating expected low adherence to treatment.
• Refusal to follow the plan of visits and examinations provided for by the protocol of this clinical trial.
• Refusal to sign informed consent.
• Infectious diseases.