Download Information For Patients Who Have Been Scheduled To Undergo

Information For Patients Who Have Been Scheduled To Undergo Diagnostic Cardiac
Catheterization Or Percutaneous Transluminal Coronary Intervention (Angioplasty)
A cardiac catheterization is an invasive diagnostic study, designed to help to evaluate a
patient’s cardiac and coronary anatomy. It is done in a specially designed cardiac
catheterization suite. For hospitalized patients, the cardiac catheterization (cath) is usually
performed urgently or emergently. For outpatients, or if an individual’s clinical findings are less
pressing, the cardiac catheterization procedure can be done electively (as an outpatient). If an
outpatient cath has been suggested, we request that you contact our office (telephone number
is noted above); to have your cardiac cath scheduled (at your earliest convenience).
On the day of your procedure, you should plan to arrive at the hospital at least an hour ahead
of your scheduled procedure time. This will allow ample time to prepare you for the cath
procedure. You will receive additional instructions from the hospital staff upon arrival, and will
be required to sign additional hospital consent forms. An intravenous line will be inserted, and
you will be provided with appropriate sedation for your procedure; you will not be totally asleep
however.
When your procedure begins, you will be brought into a cardiac cath suite (which is effectively
a modified X-ray suite). The staff will attempt to do all that is possible to see to your comfort.
A local anesthetic will be administered to your wrist, arm, or groin (depending upon the
selected sight for access of the arterial and/or venous vascular system(s). The local anesthetic
is given to “numb” the access sight, and avoid discomfort during passage of the catheter(s)
through the skin into the blood vessel. There should be no additional discomfort at any time
during the study, other than this numbing from the local anesthesia, as there are no sensory
nerve- endings present anywhere else that the catheter will traverse. For routine arterial
catheterization, a needle will then be passed into the artery that runs close to the surface
beneath the numbed skin, to obtain access to the artery.
A sheath will be placed into the artery, which is a hollow tube with a stopper on the end that
remains outside the body. The sheath is generally not much larger in diameter than a strand of
spaghetti, and will facilitate passage and exchange of the diagnostic catheters used. A catheter
(which is nothing more than a long flexible small hollow tube) is passed through the sheath,
and positioned with its tip just within the origin of the coronary arteries. The coronary arteries
are the tiny vessels which run along the outside of the heart to provide nourishment (oxygen
and nutrients) to the heart muscle, and keep it healthy. It is these coronary arteries that tend
to accumulate cholesterol plaques that cause blockages; which we refer to as arteriosclerotic
coronary heart disease (CAD).
A radiocontrast agent (iodine-containing dye) will be injected through the catheter while a
high-speed movie camera is activated through the X-ray machine. As the radiocontrast (dye) to
runs-off, down the coronary arteries, it will opacify the vessel lumen, and demonstrate the
location any of the blockages that are suspected to be present. The dye injection will be
repeated (along with high-speed digital movie imaging) in several positions (different external
x-ray camera angles), so that all of an individual’s coronary vessels can be evaluated for the
presence of narrowed segments in multiple views. This is called a coronary angiogram.
The procedure may include contrast picture(s) of the ventricular chamber, or “ventriculogram”.
A special catheter will be positioned within the ventricular chamber (usually the left ventricle),
and a burst of “dye” will be given to assess the left ventricular size, and the wall-motion and
systolic performance of the ventricle.
At the beginning or the end of the study, a dye picture may be taken of the femoral artery or
other access vessel (where the sheath is inserted). When the vascular access site is the
femoral artery (groin), often a vascular closure device (either a collagen plug, a metallic clip, or
a suture) will be used to close the artery access site. This allows a patient to be up and around
much sooner (usually within an hour or two). The alternative is to allow the access site to seal
“naturally”, by applying prolonged manual pressure, and allowing the body’s clotting system to
seal the access site sufficiently. The entire time of the diagnostic catheterization should require
no more than fifteen to thirty minutes to complete.
If no abnormality is identified (or if it is felt that a patient will not require additional therapy at
that time), a patient can should expect to leave the hospital within one-to-two hours after the
completion of the procedure. The patient will be regularly assessed by the hospital’s
catheterization laboratory staff prior to their departure, to be certain that they had not
manifested any reactions to the procedure, the dye or any medications given; and to be certain
that the effects of the sedation administered have worn off sufficiently.
If an abnormality is identified which is deemed to be severe enough to compromise blood flow,
and is otherwise felt to be “fixable” upon preliminary evaluation in the catheterization
laboratory (many blockages can be repaired or corrected at the same time directly through a
catheter), the cardiologist may elect (with your permission) to progress to an angioplasty “adhoc”.
Angioplasty is the repair procedure of a blood vessel that may ensue in individuals who require
it. Angioplasty technically means “vessel modification”. The prototype procedure (developed in
1977) involved the passage of a guidewire through the catheter, down the coronary artery, and
across the blockage. The guidewire is not much larger around than a human hair. It has a soft
supple tip and a stainless steel shaft. A tiny catheter is passed coaxially over the guidewire to
the point of the blockage. The tiny catheter has an inflatable balloon at its tip which can be
filled with dye, so the inflated balloon location can be visualized under the x-ray camera. The
inflated balloon resembles a “hot dog” (but is infinitely smaller – no larger than the true
diameter of the coronary vessel; generally 1.5 to 4.0 mm in diameter). The balloon stretches
open the vessel at the point of the blockage, and may partially compress the atherosclerotic
plaque. Once a satisfactory angiographic appearance has been achieved (with a subsequent
injection of dye into the vessel), the balloon is then deflated and removed. An improved vessel
diameter (with a theoretically improved blood flow down the vessel) will have been achieved.
Many technological modifications and improvements have been made in angioplasty over the
past few decades. There now exist a wide variety of specialized catheters for opening vessels
and/or plaque removal. These can include laser catheters, shaving or cutting catheters, suction
catheters, grinding catheters, specific plaque-modifying catheters, and stents. The
interventional cardiologist (physician operator) will select one or more catheters to perform the
angioplasty, depending upon the number of vessels involved, the vessel size(s), the number,
location, and complexity of the blockages, the appearance of the blockage on the angiogram,
and possibly additional details regarding the blockage from measurements obtained using
specific diagnostic tools (intravascular ultrasound imaging or Doppler flow wire analysis). There
are several factors that can contribute to the selection of a specific angioplasty catheter or
device.
A stent is a tiny metallic mesh tube that can be mounted on a coronary balloon, which is
deployed into the vessel and left permanently by inflating the balloon to the proper vessel size.
There exist “self-expanding” stents which come housed in a thin sheath. Once properly
positioned in the vessel, the sheath is withdrawn allowing the stent to expand to its natural size
and shape. Stents have the ability to scaffold (“prop-open”) a vessel, maintaining the vessel’s
cylindrical shape, and providing for an improved angiographic appearance. Stent use has
reduced the incidence and severity of procedural complications, and has improved the
angiographic result immediately and long-term. Because of this, most cardiologists prefer to
employ the use a stent as part of an angioplasty procedure (where possible). Newer stents are
constructed of combination metal alloys and are coated with special medications (bonded to the
metal), which are slowly released into the wall of the vessel over days to weeks. The effects of
these medications may last for weeks to months, and are designed to prevent excessive regrowth of the vessel layers (neointimal hyperplasia or fibrointimal hyperplasia), commonly
referred to as “restenosis”, which can result in a new blockage at the treated location weeks to
months later.
The risks of the diagnostic cardiac catheterization include an extremely low risk of serious
complications (stroke, heart attack, and death). These complications occur relatively rarely
(usually less than 0.1% of the time). Other minor complications can occur more frequently (but
are still rather uncommon), and include; vascular injury at the catheter insertion site
[potentially requiring a vascular repair procedure and/or blood product transfusion] (less than
2%), radiocontrast allergy (less than 2%), and kidney damage [related to radiocontrast use]
(less than 2%). Elderly patients, patients with known underlying kidney disease, and diabetic
patients may be at a somewhat increased risk for kidney problems related to the dye
(radiocontrast nephropathy). If you have ever been told that you have a dye (radiocontrast)
allergy, or have had kidney problems related to dye administration, or if you feel that you may
be at an increased risk of having a dye-related problem from your procedure, you should
contact the hospital cardiac catheterization laboratory, and your interventional cardiologist
(operator) and inform them of your concerns. Often, additional medications can be
administered to help avoid radiocontrast related clinical problems.
If an angioplasty is performed, the procedural risks are greater (which is understandable, as an
angioplasty involves a mechanical modification or correction of a coronary plaque that is
causing a vessel blockage, and a potential danger in itself). These complications include all of
those that are mentioned above for the catheterization procedure. With angioplasty, the
incidence of a procedure-related death is less than 1%, and the incidence of a heart attack is
approximately 3%. Additional potential risks (with angioplasty) include:
-Coronary vessel dissection (5-10%). This is a separation of the vessel layers.
-Abrupt coronary closure (less than 5%). This is usually related to a coronary dissection and/or
a clot (thrombus) with or without plaque debris within the vessel lumen.
-Coronary perforation (1-2%) This can result in bleeding out of the coronary vessel into the
adjacent muscle or into the pericardial space (around the heart).
-Hemopericardium with or without cardiac tamponade. Extravasation of blood into the
pericardial sac (usually from a coronary perforation) can exert an outward pressure on the
heart. This is termed pericardial tamponade or cardiac tamponade. (1%)
-Emergency coronary bypass operation (less than 0.1%)
-Restenosis [development of a recurrent blockage at the treated site] (approximately 30% with
routine angioplasty, 15% with the use of a stent, and 1 - 3% with the use of a “drug-eluting”
stent).
In the unusual event that a complication occurs, it may be necessary for your cardiologist to
perform additional procedures at his/her discretion to attempt to protect your heart and your
life. These procedures may include: insertion of an intra-aortic balloon pump (a mechanical
pump to assist with heart function while other medications are provided and mechanical
measures are considered or undertaken to provide additional stabilization), insertion of a
temporary trans-venous pacemaker (to assist your heart rhythm), and/or performance of a
pericardiocentesis (insertion of a needle and possibly also a catheter into the pericardial sac to
remove blood or fluid). During such a situation (although uncommon), it may also be necessary
for your cardiologist to select additional physicians (anesthesiologist, cardiothoracic surgeon,
etc.) to assist with your breathing and subsequent care.
The overall success rate of angioplasty in the hands of an experienced operator is about 9598%. If an angioplasty is performed, you can usually expect to remain in the hospital overnight
and be released the following morning (barring any other complicating issues). Rarely (in an
anatomically lower risk procedure completed before the mid-afternoon), you may be allowed to
depart the hospital during the same day.