At its core, surgery is the art of inflicting well-meaning trauma in a (moderately) controlled environment.
We slice and dice, hoping that the anaesthetist isn't too distracted and blood mostly stays inside the patient.
But while the most obvious injury in cardiac surgery is the giant saw wound through the sternum, the poor kidneys often take collateral damage in the process.
In fact, post-op acute kidney injury strikes up to 50% of patients undergoing elective cardiac operations.
Each of these events increases mortality, and the risk of developing long-term renal failure.
Historically, the typical management plan consisted of prescribing a (very evidence-based) deluge of IV fluid, the crossing of fingers, and hoping the creatinine behaves.
But all that is about to change.
Enter dapagliflozin
Because there are some drugs that just can't stay out of the headlines.
Originally designed to lower blood glucose in type 2 diabetes, dapagliflozin has evolved into the Swiss Army knife of renal and cardiac protection.
It works by blocking sodium and glucose reabsorption in the proximal tubule, lowering glomerular pressure, and keeping the nephron cosy.
What did MERCURI-2 test?
Which brings us to the all important research: the MERCURI-2 trial, published in JAMA.
They randomised 784 adult patients having elective cardiac surgery across the Netherlands to receive either dapagliflozin or a sneaky placebo.
The dosing schedule was simple: with just one tablet of 10mg daily, starting the day before surgery.
And the results?
Dapagliflozin slashed the incidence of AKI within the first 7 days down to 28%, compared to 52% in the placebo group (P < 0.001).
This was more easily achieved with less severe injuries, with stage 1 AKIs dropping to 23% from 40%, and stage 2 dropping to 4.1% from 13% in the placebo group.
However, secondary outcomes like major cardiac events, length of stay, or new arrhythmias showed no significant difference between groups.
The caveats
Of course, like all studies, the trial had its quirks and imperfections.
The studied population was 97% White and 76% male, so it's unclear if we can generalise beyond this.
And patients already taking SGLT-2 inhibitors were excluded from the trial (which at this point, is quite a large number of people).
But if four little tablets can make such a massive difference, with no real risk, it's hard to see the downside.
