Recent news reports of celebrity Rosie O'Donnell's heart attack mention one of the arteries in her heart was 99% blocked. How do doctors diagnose a blockage? A procedure called cardiac catheterization (or cardiac cath for short).
I talked with Dr. Michael Twyman, preventive and invasive cardiologist on staff at Des Peres Hospital, about a newer technique for diagnostic cardiac caths that goes through the wrist.
First a bit of history. Cardiac catheterization has evolved over a period of at least 400 years, starting with the description of the circulation of blood in the early 1600s followed by the measurement of arterial pressure about 100 years later. By the 19th century, research in cardiovascular physiology and studies on animals had yielded valuable information about measuring intra-cardiac pressures. Human cardiac catheterization was then developed after Werner Forssmann performed the first right heart catheterization on himself in 1929. Forty years later, catheter-based interventions had been pioneered and today cardiac catheterizations are commonly performed to diagnose and treat heart conditions.
"Cardiac catheterization is a minimally invasive procedure that involves threading a small tube called a catheter through a blood vessel to the heart," said Twyman. "It may be done to diagnose or evaluate coronary artery disease, congenital heart defects or problems with heart valves, or to identify causes of heart failure or cardiomyopathy. Cardiac catheterization also may be performed as an interventional procedure to treat heart attacks, open blocked arteries, or repair narrowed heart valves."
Twyman explained that catheters used in cardiac catheterization can be inserted into either the femoral artery in the groin or through the radial artery in the wrist.
"Because the femoral artery is larger and provides a more direct route to the heart, it has become the standard entry site for the procedure," said Twyman. "However, access through this artery can cause problems, such as bleeding at the puncture site or nerve damage."
Cardiac catheterization through the femoral artery also requires that the patient lie flat without bending the leg for two to six hours after the procedure to allow the artery to heal. Even then, internal bleeding may occur that could be severe enough to require blood transfusions or surgery to repair the artery.
"For some patients, radial artery catheterization could be a better choice," said Twyman, who performs most of his diagnostic cardiac caths through this wrist approach.
"The radial artery is considerably smaller and located closer to the skin surface than the femoral artery. Consequently, it is much easier to apply direct pressure to the puncture site to stop the bleeding following catheterization," explained Twyman. "After a compression device is placed on the wrist, patients can get out of bed and walk around immediately after their procedure. They tend to have a shorter hospital stay and a faster recovery time, and are more comfortable post-procedure following a radial artery catheterization compared to the femoral approach."
Twyman noted that patients should avoid heavy lifting with the affected hand, but are otherwise able to use it for activities such as eating or writing. Normal activity with the hand can be resumed after about three days.
Twyman also pointed out that not all patients are candidates for radial artery catheterization. "They must have good blood supply to the hand through both the radial and ulnar arteries in the rare case that the radial artery becomes blocked following the procedure," he said. "If this happens, the ulnar artery can take over and supply enough blood for the entire hand."