CGM Improves Blood Sugar Control After Heart Surgery

What Was Studied and Why It Matters

Keeping blood sugar under control after major heart surgery is critical. When blood sugar runs too high or too low following coronary artery bypass grafting (CABG) — a procedure that reroutes blood around blocked heart arteries — patients face higher risks of infections, slow healing, and serious complications. Researchers wanted to know whether using a real-time continuous glucose monitor (CGM) during recovery could help doctors manage blood sugar more effectively than traditional fingerstick checks alone.

What the Researchers Did

This randomized clinical trial enrolled 91 adults with type 2 diabetes who were scheduled for bypass surgery. Patients were split into two groups:

• Test group (48 patients): Wore a Dexcom G6 CGM that sent live glucose readings to the care team via telemonitoring, allowing nurses and doctors to adjust insulin in real time.
• Control group (43 patients): Also wore a CGM, but the readings were hidden — staff relied on standard fingerstick point-of-care checks as they normally would.

The main goal was to measure time in range (TIR) — the percentage of time a patient's blood sugar stayed within the healthy target zone of 70–180 mg/dL.

What They Found

The results were clear and meaningful. Patients whose care teams had access to live CGM data spent significantly more time in the healthy blood sugar range:

• CGM group: 60.3% time in range
• Standard care group: 50.3% time in range
• That's a 10 percentage point improvement — a clinically significant difference

The CGM group also had lower average glucose levels and spent less time with dangerously high blood sugar. Importantly, there was no increase in low blood sugar (hypoglycemia) events — a common concern when tightening glucose control in hospital settings.

What This Means for Real Patients

If you or a loved one with type 2 diabetes is scheduled for heart bypass surgery, asking your surgical team about CGM monitoring during recovery is a worthwhile conversation. Real-time glucose data allows medical staff to respond faster and more precisely than waiting for scheduled fingerstick checks.

For patients who already use CGM devices at home — like the Dexcom G6 used in this study — continuing that technology through a hospital stay may offer a smoother transition and better outcomes. MDS Diabetes carries a wide range of CGM supplies and sensors to support ongoing glucose monitoring before and after procedures.

Bottom Line

A real-time CGM worn during post-surgery recovery helped type 2 diabetes patients stay in healthy blood sugar ranges 10% more of the time compared to standard fingerstick monitoring — and did so safely, without causing more low blood sugar episodes. As CGM technology becomes more accessible, this study makes a strong case for expanding its use beyond everyday diabetes management into critical hospital care settings.