Could beetroot protect kidneys during heart procedures? New trial points to yes
Kidney injury is one of the most feared complications of coronary angiography. Now, a new clinical trial led by Professor Amrita Ahluwalia at Queen Mary University of London suggests that a short course of inorganic nitrate, commonly found in beetroot, could offer a simple, low-cost solution.
Published in the European Heart Journal, the NITRATE-CIN trial found that five days of once-daily inorganic nitrate before and after coronary angiography significantly reduced the risk of contrast-induced nephropathy (CIN) in patients undergoing the procedure for non-ST-elevation acute coronary syndrome, a condition where blood flow to the heart is reduced but not completely blocked.
CIN is a form of acute kidney injury caused by the iodinated contrast dye used during angiography. It affects an estimated one in three high-risk patients and accounts for a third of all hospital-acquired acute kidney injuries in the UK. With over 250,000 coronary angiograms performed each year, the scale of the problem is significant, and so is the potential for improvement.
In this double-blind, placebo-controlled trial, 640 patients undergoing angiography at Barts Health NHS Trust were randomised to receive either potassium nitrate (319 patients) or a placebo capsule containing potassium chloride (321 patients). The results were clear: nitrate-treated patients had substantially lower rates of CIN (9.1% vs. 30.5%), fewer myocardial infarctions during the procedure (2.7% vs. 12.5%), improved kidney function at three months, and fewer major adverse cardiac events at one year (9.1% vs. 18.1%).
The underlying mechanism is thought to involve nitric oxide. Levels of this protective molecule fall during angiography, which increases oxidative stress and damages kidney tissue. Inorganic nitrate, a precursor to nitric oxide, appears to restore balance, offering a new way to protect renal and cardiovascular function.
Professor Ahluwalia said, “This trial suggests that a simple five-day regime of low-cost inorganic nitrate capsules eliminates the risk of what were, up until now, unavoidable damaging effects. We hope to confirm these findings in a large multi-centre trial in the near future, but the results of NITRATE-CIN give us hope.”
The findings have been welcomed by Heart Research UK, who funded the trial. Chief Executive Kate Bratt-Farrar noted the study’s potential to change national coronary angiogram protocols and reduce the number of patients who experience serious, and sometimes fatal, kidney complications.
With a 20% mortality rate for patients who develop CIN, the case for further investigation is strong.
Read the full study in the European Heart Journal