Contrast-induced nephropathy (CIN) is a common complication in patients admitted for
acute coronary syndrome (ACS) who undergo percutaneous coronary intervention (PCI).
Although the deterioration of renal function is generally reversible, avoiding CIN is of
great importance as it is associated with worse prognosis, including greater need for
renal replacement therapies and greater mortality.
Inorganic nitrates (NO3-) are the most promising therapy to prevent CIN, due to their
ability to be metabolized to nitric oxide (NO), whose vasodilator effect protects renal
perfusion. In addition, NO has other potential benefits in ACS due to its
anti-inflammatory, antiproliferative, endothelium protective, and platelet aggregation
inhibitor effects.
The recent NITRATE-CIN study has shown that the administration of 12 mmol/24 h of KNO3
for 5 days to patients admitted for non-ST elevation (NSTE) ACS undergoing PCI not only
significantly reduced the risk of CIN, but also prevented the deterioration of kidney
function and significantly reduced major cardiovascular complications (MACE) during
follow-up.
However, there is currently no comercially available presentation for KNO3 and its
administration could be associated with hyperkalemia.
Furthermore, evidence of its use during admission for NSTE ACS comes from a single-center
study with a small representation of Mediterranean population, which raises doubts about
the validity of these results in our patients.
Drinking beetroot juice is a very promising alternative to administer NO3- during
admission for NSTE ACS, due to its greater availability, simplicity of administration and
minor risk of adverse effects such as hyperkalemia.
500 mL of beetroot juice daily contain approximately 11 mmol of NO3-, their consumption
increases plasma NO similar to KNO3 and, in patients with chronic coronary syndrome, has
been shown to reduce the risk of stent restenosis and MACE during follow-up, without
significant adverse effects.
Objetives:
Describe the effect of dietary supplementation with beetroot juice during hospital
admission for NSTE ACS in the prevention of CIN after PCI.
Assess the tolerance of beetroot juice supplementation during admission by NSTE ACS
and its possible relationship with adverse effects such as hyperkalemia.
Analyze the effect of the administration of beetroot juice during admission and
recommendation upon discharge to maintain a diet rich in vegetables with a high
content of nitrates on renal function during follow-up, including the need for
initiation of renal replacement therapies.
Evaluate the relationship between the effect of the administration of beetroot juice
during hospitalization and the recommendation upon discharge to maintain a diet rich
in vegetables with high nitrate content with MACE during the first year of follow-up
after NSTE ACS.
Study design:
PROBE study (Prospective Randomized Open, Blinded End-point) Nutritional intervention
study. Unicentric. Study population: Patients >18 years old who enter our center with a
diagnosis ofNSTE-ACS with indication for PCI and moderate or high risk of CIN (Mehran
scale score not including contrast ≥ 6).
Intervention: Supplementation with 500 mL of beetroot juice daily in 2 doses of 250 mL,
for 7 days or until discharge from admission for NSTE-ACS. Recommendation to maintain a
diet rich in vegetables with high nitrate content after discharge.
The control group will follow the usual management and diet. In both groups, it will be
administered treatment with hydration and statins to prevent CIN.
Analyzed Variables:
Relationship between supplementation with 500 mL of beetroot juice daily during admission
for NSTE-ACS with:
Incidence of CIN during admission according to KDIGO creatinine criteria (increased
Serum creatinine ≥0.3 mg/dL in the first 48 hours or ≥1.5 times the baseline value
during the week after PCI)
Incidence of dropout due to juice intolerance in the intervention group,
hyperkalemia (defined as K>5.5 mEq/L with previous normal values) or others adverse
events during admission.
Evolution of glomerular filtration rate and need for renal replacement therapy
during the first year after PCI.
Incidence of MACE and total mortality during the first year after PCI. Personal
history, characteristics of NSTEA CS and PCI and creatinine values at admission,
after PCI, during follow-up and treatments administered values will also be
registered.
