Creating a Road Map To Your Heart

add other information about the topic, treatment options at PAC, physician referrals, etc. here.

Glenn Morris, DO
Cardiologist

When former president Bill Clinton experienced chest pain and shortness of breath in September or 2004, his physician ordered an angiogram, the standard test for diagnosing heart disease. Blocked arteries that showed up clearly on the angiogram told doctors that coronary artery bypass surgery was the best treatment option.

            Coronary x-ray angiography allows doctors to look inside the body and literally get a real-time image of arteries and blood flow. Performed in a heart catheterization lab, the procedure involves making a small incision, usually near the groin, and inserting a thin tube which is gently guided through arteries to the chest area.

            Contrast dye is injected into the arteries, then a series of x-rays are taken, following the blood as it travels to the heart. The images, which the radiologist follows on a monitor, show where an artery might be blocked or where there is reduced blood flow, both the result of a build up of plaque on the artery walls, indicating a high risk for a future heart attack.

            Although x-ray angiography provides physicians with a graphic view of what’s happening in critical blood vessels, it’s not for everyone. It’s an invasive procedure and entails a small degree of risk that it might trigger a stroke, heart attack or even death.

            It’s performed in a hospital setting and may require an overnight stay for observation after the procedure. And it typically causes some degree of anxiety and discomfort for the patient who remains awake, although lightly sedated, throughout the session, which could last from one to three hours.

            A major advantage offered by x-ray angiography stems from the fact that it is invasive. When a blockage is discovered that’s suitable for treating with balloon angioplasty, the cardiologist can use the same catheter to carry a tiny balloon to the site of the blockage, inflate it-pushing the plaque back against the artery wall-and then insert a mesh stent to keep the artery open. Diagnosis and treatment can all be performed as part of the same procedure.

            But in about one quarter of x-ray angiographies, the results are normal. Ideally, cardiologists would like to have a less invasive way of screening out these normal patients with a less invasive test.

Newer Imaging Options

            Other imaging technologies, including computed tomography (CT) angiography and magnetic resonance (MR) angiography, have been adapted in an effort to address this problem, and they’re gradually improving their ability to get usable images of the coronary arteries with less invasive techniques.

            Magnetic resonance angiography, in use for about 10 years, has been steadily improving the quality of imaging. It offers a valuable alternative to traditional angiography for some patients and is significantly less expensive, costing about $1000 to $1500 per procedure, compared with $3000 to $4000 for a diagnostic x-ray angiogram. Traditional angiography is more expensive because it has to be performed in a sterile cath lab by a medical specialist.

            MRA, because it uses a powerful magnetic field, can’t be performed on patients who have metal in any part of their bodies, including those with pacemakers, hear valves or surgical clips.

            Patients who are claustrophobic are often unable to undergo MRA exams, although newer, more open magnetic resonance machines are being developed. Motion is an obstacle to getting a good image so patients have to be able to repeatedly hold their breath for 15 to 20 seconds at a time.

            CT angiography is also sensitive to motion, but increasingly CTA is valued for its ability to identify calcium build up in artery walls, a measure cardiologists believe may provide a better indication of future risk than x-ray angiography is able to deliver.

            Some cardiologists are now turning to a new technique, intravascular ultrasound (IVUS), that provides a new measure of heart disease they say may be more relevant to a patient’s prognosis than blockages and narrowing of arteries captured on traditional angiography.

            Dr Steven Nissen, head of clinical cardiology at the Cleveland Clinic, says IVUS shows what x-ray angiography can’t, the 90 to 95 percent of atherosclerotic plaque hidden within the vascular wall.

            According to Dr. Nissen, a patient can have a normal image on an angiogram with no impaired blood flow, yet have large, unstable plaques within the artery wall. When the plaque breaks through the arterial wall, it can cause a blockage that triggers a heart attack.

            So after performing an angiogram Dr. Nissen inserts the ultrasound probe, less than 1/25^th of an inch across, to create cross sectional images of the artery walls. Armed with information from the angiogram-showing the degree of blockage within the artery-plus the ultrasound cross-section image-showing what’s happening inside the artery wall-Dr. Nissen is better able to evaluate the most effective treatment for heart patients.

            Autopsy studies show that in two of every three deaths from heart attach the attack occurred at a point where the artery was not significantly narrowed, supporting the theory that soft, fatty plaque that gradually expands and bursts through the wall of the blood vessel may pose more of a danger than plaques lining the artery.

            Autopsy findings also indicated that smoking and a high body mass index were highly predictive of having unstable plaques within the artery walls

            The good news is that a number of clinical trials show that unstable plaques within the arterial wall shrink when patients are treated with cholesterol lowering statin drugs. Increasingly, doctors are prescribing statin drugs for patients with high cholesterol levels.

            Coronary artery disease is the leading cause of death among both men and women in the United States. Some half a million Americans die each year from heart attacks, and an estimated 12 million Americans alive today either suffer angina or have had a heart attack. Imaging studies benefit these patients as well as the millions more who because of age, heredity, smoking, obesity, lifestyle or other factors face an increased risk of heart disease.

            As physicians have access to increasingly sophisticated tools they will be able to get a more comprehensive picture of blood flow within arteries plus plaque build up within vessel walls. When identified early enough many patients can be treated with diet, lifestyle changes and medication. When blockages are more severe, either balloon angioplasty plus stenting or coronary artery bypass surgery may be necessary to get blood flowing to the heart again.

3/1/2005

Back to Newsroom