Diagnosis

Click the icon to see an image of cardiac catheterization.

Click the icon to see an image of dye injected into the coronary arteries.

Major complications include stroke, heart attacks, and kidney damage. These risks are very low (about 0.1%), however, if the procedure is done in an experienced medical center (one that performs at least 300 of these operations every year). Allergic reactions can also occur. The procedure is expensive, and between 10 - 30% of patients who have this procedure have normal results.

Magnetic Resonance Angiography (MRA). MRA is a very promising noninvasive imaging technique that can provide three-dimensional images of the major arteries to the heart and identify disease with high accuracy. Experts believe this approach will eventually be a good alternative to angiography.

Kidney Tests

Tests that measure kidney function can help predict which patients are at greatest risk of heart attack, stroke, or death from heart disease. Kidney tests measure proteins in the blood that are filtered through the kidneys. These proteins include creatinine and blood urea nitrogen (BUN). A more recent type of kidney test measures the protein cystatin C. Recent research suggests that the cystatin C kidney test may be better at predicting cardiovascular risks in elderly patients.

Biologic Markers

When heart cells become damaged, they release different enzymes and other molecules into the blood stream. Elevated levels of such markers of heart damage in the blood or urine may help predict a heart attack in patients with severe chest pain and help determine treatment. Some markers include:

• Troponins. The proteins cardiac troponin T and I are released when the heart muscle is damaged. Both are proving to be among the best diagnostic indications of heart attacks. They help identify many individuals with ACS, such as older women with other serious conditions that might otherwise have been misdiagnosed.
• Creatine kinase myocardial band (CK-MB). CK-MB has been a standard marker, but the MB fraction is not as accurate as troponin levels, since elevated levels can appear in people without heart injury.
• Myoglobin. Myoglobin is a protein found in heart muscles. It is released early in the injured heart and may be useful in combination with CK-MB and the troponins.
• Other markers are proving to be helpful in identifying heart problems but are not routinely measured at this time except in clinical studies. They include fibrinogen (a protein involved in blood clotting) and C-reactive protein (a product of the inflammatory process). For example, persistently high levels of C-reactive protein in patients with unstable angina may be strong indicators of a future heart attack.