Introduction to Cardiac Catheterization and Angiography:Left
cardiac or heart catheterization (cath) is a specialized study of the
heart during which a catheter is percutaneously inserted into the femoral
artery of the groin or into the the brachial or radial artery of the upper
extremity. Coronary angiography is a definitive, gold standard diagnostic
procedure in establishing the the presence and severity of coronary artery
disease (CAD). Over a million cardiac cath procedures are performed annually
in the United States, and it has established itself as the most common
hospital procedure in senior Americans over the age of 65 years.
Under x-ray fluoroscopy, a catheter is guided to the
heart and the tip is manipulated to engage the ostium of the coronary
artery (or of grafts in patients who have had prior coronary artery bypass
graft surgery). Pressure is measured at the tip of the catheter and angiograms
(angios) or arteriograms are obtained while hand-injecting injecting an
iodinated contrast material through the catheter. Coronary angios are
obtained with the use of pre shaped (usually Judkins, but occasionally
Amplatz, multipurpose or other) 5 to 7 French diameter diagnostic catheters.
After engaging the ostium of the coronary artery it is confirmed that
the tip of the catheter is free, and not against the wall of the artery,
under a sub-intimal plaque, deep throated into a small vessel or mechanically
obstructing an ostial or very proximal stenosis. This is accomplished
by confirming that the pressure is not damped and with the use of a test
injection using a small amount of contrast material.
During coronary angiography, full-motion x-ray images are viewed
and recorded with the use of a video camera, as contrast material
is manually injected into the ostium of the coronary artery. In the
majority of modern cardiac catheterization suites, the images are recorded
digitally. While many labs also film a cineangiographic 35 mm copy for
review and archiving purposes, the trend is to go "cineless" and record
the images on large computer optical disks arranged in the form of a
digital "jukebox" that allows online review of current and archived
cases. Copies are made on a CD-ROM for purposes of distribution. Various
views or projections of the coronary angiograms are obtained by rotating
the x-ray video camera around the patient. This will be discussed in
another segment of this lesson.
Worldwide, a percutaneous femoral artery approach is the most common
form of arterial access during cardiac cath. A percutaneous brachial artery
approach is occasionally used in patients with severe peripheral vascular
disease or when the groin approach is not possible or technically difficult.
In an attempt to ambulate patients early after an outpatient or "same
day" procedure, some labs employ a percutaneous radial artery approach
for diagnostic cardiac cath and even for coronary interventions. "Left
heart" catheterization includes measurement of aortic and left ventricular
pressures, selective coronary angiograms and a left ventricular angiogram.
If the patient has had prior coronary bypass surgery, angiograms of the
vascular conduits (saphenous veins and internal mammary artery bypass
grafts) are also obtained.