Heart Tests Offer New Options For Diagnosis

During cardiac catheterization, an interventional cardiologist inserts a catheter into an artery through a small incision in the groin or arm. Through this catheter, the physician can perform an angiogram by injecting an opaque dye that makes the vessels show up like dark tree branches on a monitor. If there are any blockages, even tiny ones, the physician can usually see them and, in many cases, can immediately repair them without requiring the patient to undergo a second procedure.

Cardiac catheterization is certainly less invasive than undergoing open-heart surgery to repair vessels, but it still carries some surgical risks, such as bleeding, swelling, or bruising, but more serious complications may include infection, damage to the heart or blood vessels, and blood clots. Death is rare but possible, occurring about one percent of the time. That said, about a quarter of patients who undergo catheterization turn out to have no blockages at all. So what if those patients could get a diagnosis without the risk?

A new generation of scanning technology allows physicians to see inside the body with amazing detail, without any incisions. Instead of the dark tree branches of an angiogram image, the physician can see full-color, 3-D images of the heart and the blood vessels that supply it and the rest of the body.

"New computed tomography (CT) scans--similar to an X-ray, but in much greater detail--use multiple 'slices' or imaging planes to gather detailed information of the heart and blood vessels," says Dr. Debabrata Mukherjee, director of the Peripheral Intervention Program and associate director of the cardiac catheterization laboratories at the UK HealthCare Linda and Jack Gill Heart Institute at the University of Kentucky. He is also an associate professor of internal medicine at the UK College of Medicine.

Use of this imaging technology in diagnosis heart disease has grown so widely that Dr. Mukherjee has authored a textbook to help other physicians understand the best use of these imaging technologies, and UK plans to open a new facility dedicated soley to cardiac imaging at the Gill Heart Institute in 2008. Other imaging technology includes MRI (magnetic resonance imaging), which utlizies a powerful magnet instead of radiation; and nuclear medicine, which involves injecting radioactive tracer molecules to measure blood flow. While these imaging options are not new, the level of precision and detail has improved dramatically. By combining these technologies, physicians can get a better view of the heart than ever before.

This is good news for patients with risk factors--high blood pressure, high cholesterol, diabetes--whose level of heart disease is unknown. However, patients with more urgent cases, or patients with other problems such as irregular heartbeats, are better served by catheterization. Imaging also may not be as good as angiogram in displaying tiny blockages or certain kinds of blockages, such as calcium deposits rather than fatty plaque.

But for those who would otherwise be treated with a wait-and-see approach, imaging can provide quick, detailed answers for them and their physician.

"This non-invasive form of imaging of the blood vessels appears safer than putting catheters directly into blood vessel and may identify life threatening blockages in the heart in appropriately indicated patients," Dr. Mukherjee says.

Most importantly, Dr. Mukherjee recommends discussing with your doctor the risks and benefits of any procedure if you're trying to determine the health of your heart.