1. Diabetics Don't Have Classic Symptoms of Heart Disease
Diabetes affects the nerve endings because of persistently elevated blood glucose levels. This neuropathy can cause numbness in the feet. It can also cause the nerve endings in heart to be less responsive to the symptoms of low blood flow. Classic angina is described as a weight or heaviness in the chest that often radiates to the arm or shoulder. A diabetic may present with the classic symptoms but can also present with shortness of breath, burning chest pain (mimicking indigestion), generalized fatigue or diabetic keto-acidosis in those requiring insulin therapy. When a diabetic patient shows up in the emergency room with nonspecific complaints, the possibility of an acute coronary syndrome must always be considered.
2. Diabetics Have More Reactive Platelets
Platelets are small oval structures that help stop bleeding when you cut yourself. They circulate throughout the blood stream. When a coronary artery develops a severe narrowing these platelets can get stuck in the narrowing and clump together. During a heart attack or a stroke the platelets become activated, inducing a cascade of events that propagates clotting throughout the blood vessel. Elevated blood sugar causes the platelets to be more reactive and prone to clotting. When treated with medicines to reduce the clotting the platelets are less responsive than in non-diabetics. The anti-platelet medications needed to overcome this problem in diabetics can result in bleeding, which can reduce the effectiveness of heart attack treatments such as stenting or bypass surgery.
3. Diabetics Have Smaller Arteries
Diabetics have smaller coronary blood vessels when compared to non-diabetics. The atherosclerotic process is so aggressive and diffuse in diabetes that often the a entire artery is affected. In most adults the coronary arteries average 3 to 4 mm. Diabetic vessels are often 2.5 mm or smaller. These small vessels are often difficult to treat with angioplasty and stenting. Bypass surgery is often a better choice when diabetes is involved because of this diffuse disease process.
4. Diabetics are More Likely to Have Blockages in Multiple Arteries
Because of the diffuse nature of diabetic atherosclerosis, patients with diabetes are more likely to have multiple arteries narrowed when they haven an angiogram. This increases the risk of percutaneous procedures and increases the likelihood that bypass surgery will be needed. Multi-vessle disease can also cause a decrease in heart function that can increase mortality with cardiovascular procedures.
5. Diabetics Have Higher Rates of Repeat Procedures
When a diabetic has a stent implanted, the risk of stent re-narrowing (restenosis) is higher with older conventional bare metal stents or with drug eluting stents. This results in a higher rate of repeat procedures to keep the artery open, which can increase the rate of complications including bleeding and kidney problems. The drug eluting stents have been a dramatic improvement over the bare stents. Major risk factors for restenosis include long segments of narrowing, small vessels and multiple stents needed to treat the narrowing, all of which are present more commonly in diabetics. After bypass surgery, diabetics are more likely to have failure of a venous graft because of higher platelet reactivity, diffuse atherosclerosis and small vessels downstream from the graft.
