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| 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 subintinmal 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.
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