Does metformin treatment improve heart enlargement in coronary artery disease?

This study investigated if metformin (Glucophage) improves left ventricular hypertrophy (LVH; enlargement of the left lower chamber of the heart) in coronary artery disease (CAD). They found that this treatment improved LVH and other CAD symptoms. 

Coronary artery disease (CAD) is a disease of the arteries supplying blood to the heart muscle. Left ventricular hypertrophy (LVH) is a term used to describe an enlarged left ventricle in the heart. LVH is common in patients with heart disease caused by a reduced oxygen supply. LVH has a significant impact on CAD prognosis. Reducing LVH lowers the risk of cardiovascular events (CVEs). These include stroke, heart attack or death.

There is a strong link between LVH and insulin resistance (IR). IR leads to poor blood sugar control. IR can lead to diabetes if it is not treated. Metformin is a drug used to treat diabetes. It can also reduce IR. It is unclear if metformin has an effect on LVH in patients with IR or prediabetes. 

This study included 63 patients with CAD and IR or prediabetes. Patients were randomly assigned to treatment with metformin (2000 mg/day) or placebo (inactive drug). Treatment lasted 12 months. An MRI scan was performed at the beginning and end of the trial. Blood samples were also taken. LVH was assessed by measuring certain parameters. These included LV mass indexed to height (LVMI). Heart function was assessed by measuring parameters including LV ejection fraction (LVEF).

Metformin treatment significantly improved LVMI. There was no difference in other heart outcomes at 12 months. Metformin treatment reduced the level of oxidative stress proteins. If these are high can cause tissue damage. Metformin did not alter blood sugar control. This treatment led to a significant reduction in body weight and systolic blood pressure. Metformin was generally well tolerated. Diarrhea, flatulence and abdominal discomfort were the most common side effects.

The authors concluded that metformin improved LVH and other CAD parameters.

This study included a small number of patients. More investigation is needed.