Heart surgery trials have deliberately given a GLP-1 around the operation, and it did not raise harm in them. Four randomized trials of liraglutide covered 446 cardiac surgery patients [1]. Death, complications and hypoglycemia showed no difference. The intervals are too wide to call that proof of safety.
Those trials asked whether the drug helps control blood sugar during surgery. Whether a weekly GLP-1 you already take should be paused beforehand is a different question. It turns on food left in the stomach, and stopping a GLP-1 before surgery covers it.
Why a GLP-1 was tried in heart surgery
High blood sugar around heart surgery is linked to wound infection, kidney injury and death. The usual fix is intravenous insulin, which can drive glucose too low [1].
A GLP-1 lowers glucose only when glucose is raised. In principle that separates control from hypoglycemia, the same logic behind why these drugs rarely cause low blood sugar alone.
What the trials found
The largest trial randomized 278 patients in four Dutch hospitals [2]. They got 0.6 mg of liraglutide the evening before surgery and 1.2 mg after anesthesia began, or placebo.
Extra insulin was needed by 43% on liraglutide against 61% on placebo. Blood glucose ran lower. Hypoglycemia, nausea, deaths and complications did not differ.
A Japanese trial gave 70 people with type 2 diabetes low-dose liraglutide plus insulin, or insulin alone [4]. Glucose stayed closer to target on the combination. Insulin dose changes were needed far less often.
Both trials fit the 2026 review's criteria. Read them as parts of that pool rather than extra confirmation of it.
What 446 patients can and cannot show
Pooled, 30-day mortality came out at a risk ratio of 0.42, interval 0.06 to 2.81 [1]. That rests on one death among 161 patients against three among 160.
Any complication ran 0.92, interval 0.74 to 1.14. Cardiac events ran 1.08. Hypoglycemia ran 0.85, interval 0.34 to 2.13. Nausea and vomiting came out at 3.01, interval 0.26 to 35.27.
A separate review of bypass surgery reached the same shape [3]. Postoperative glucose was lower with a GLP-1, and nothing else differed.
If you take a GLP-1 and have heart surgery coming
Tell the anesthetist and the surgical team what you take and when you last injected. These drugs slow the stomach, and food can remain after an overnight fast.
Nothing here is a reason to start, stop or change a dose before an operation. That decision belongs to the team doing it. Other surgical outcomes are covered in blood clots after surgery and hospital stay after surgery.