Insufficient supply of oxygen to the heart muscle without the usual symptoms. Silent ischemia is particularly prevalent in people with diabetes.
People with diabetes are at increased risk for coronary artery disease (CAD), in which the coronary arteries feeding the heart muscle become narrowed by a substance called plaque, blocking the supply of oxygen-rich blood. CAD can cause chest pain or discomfort (angina), irregular heartbeats (arrhythmias), or a heart attack (myocardial infarction). Silent ischemia is defined by a lack of these symptoms.
People with diabetes have a prevalence of silent ischemia of about 10% to 20% compared with a rate of 1% to 4% in nondiabetic individuals. Researchers believe this increased risk is due to autonomic neuropathy (nerve disease). Silent ischemia may help explain why CAD is usually more advanced when it is diagnosed in people with diabetes.
Silent ischemia is treated in much the same way as symptomatic ischemia. Nitrates such as nitroglycerine are used to relax and widen blood vessels, allowing more blood to flow to the heart. Beta blockers, calcium channel blockers, ACE inhibitors, antiplatelet medicines, and blood thinners are used to lower blood pressure and cholesterol levels, slow the heart rate, relax blood vessels, reduce strain on the heart, and prevent clots from forming. People who don’t respond adequately to medications may need a procedure such as angioplasty or coronary artery bypass grafting (CABG) to supply blood to the heart.