Page 477 - Cardiac Nursing

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C HAPTER 2 0 / Cardiac Catheterization 453
catheter into the coronary artery during left heart catheterization. shown equivalent clinical outcomes in patients deferred for revas-
The catheter is placed distal to the segment of interest and gradu- cularization without the cost of PCI and the risk of restenosis.
ally pulled back to visualize the vessel wall. The two-dimensional
images are displayed on a monitor that allows evaluation of lesion FFR and Coronary Vasodilatory Reserve
stenosis, extent of disease and assessment of post intracoronary During PCI: ACC/AHA/SCAI Practice
stent placement. Guidelines 11
Class IIa indications:
IVUS Imaging During PCI: ACC/AHA/SCAI
Practice Guidelines 11 1 It is reasonable to use intracoronary physiologic measurements
in the assessment of the effects of intermediate coronary
Class IIa indications: stenoses (30% to 70% luminal narrowing) in patients with
1. Assessment of the adequacy of deployment of coronary stents, angina symptoms. Coronary pressure or Doppler velocimetry
including the extent of stent apposition and determination of may also be useful as an alternative to performing noninvasive
the minimum luminal diameter within the stent. (Level of evi- functional testing to determine whether an intervention is war-
dence: B) ranted. (Level of evidence: B)
2. Determination of the mechanism of stent restenosis and to en-
able selection of appropriate therapy. (Level of evidence: B)
3. Evaluation of coronary obstruction at a location difficult to im- NURSING CARE OF PATIENTS
age by angiography in a patient with suspected flow-limiting UNDERGOING CARDIAC
stenosis. (Level of evidence: C) CATHETERIZATION
4. Assessment of a suboptimal angiographic result after PCI.
(Level of evidence: C)
Nurses working in cardiac catheterization laboratories fill many
5. Establishment of the presence and distribution of coronary cal-
roles. The basic roles needed in a catheterization laboratory dur-
cium in patients for whom adjunctive rotational atherectomy is
ing a procedure are scrubber, recorder, and circulator. In some
contemplated. (Level of evidence: C)
laboratories, the nurses scrub and assist in the procedure; in oth-
ers, they are responsible for monitoring pressure and cardiac
Coronary Flow Reserve (CFR) rhythm, assisting with hemodynamic studies such as CO deter-
mination, and administering IV procedural sedation. The nurse
The normal physiologic response to increased myocardial demand may visit the patient before the procedure to teach and help in
is enhanced blood flow by vasodilatation of epicardial and resist- preparing the patient or after the procedure to evaluate puncture
ance vessels. The ability to increase coronary blood flow by re- site stability. Ideally, the nurse has a background in intensive or
ducing vasomotor tone to meet myocardial demand in response to coronary care and a thorough knowledge of cardiovascular drugs,
a physiologic stimulus is called CFR. In the presence of a signifi- arrhythmias, the principles of IV procedural sedation, sterile tech-
cant lesion, the epicardial artery and microvascular coronary bed nique, cardiac anatomy and physiology, pacemakers, and the con-
compensate by vasodilation. In response to a physiological or cepts of catheter management for coronary angiography and in-
pharmacological stress, the flow resistance in the coronary vascu- tervention. Changes in the patient’s emotional status, alertness,
lature is unable to increase myocardial demand further by vasodi- vocal responses, and facial expressions are important indices of the
lating, causing a state of impaired CFR. Measurement of CFR in patient’s tolerance of the procedure. The nurse’s alertness to these
the catheterization laboratory is performed by placement of an in- clues and early intervention with reassurance or appropriate med-
tracoronary Doppler wire into the coronary artery and adminis- ication may help to prevent more serious events. Training in ad-
tration of an adenosine infusion as a stress agent to evaluate the vanced cardiac life support is a requirement for catheterization
microcirculation. 32 laboratory nurses and those nurses caring for patients after the
procedure.
Fractional Flow Reserve (FFR)
Complications and Nursing Care
The FFR is the fraction of maximal coronary blood flow that goes During Cardiac Catheterization
through the stenotic vessel. The FFR calculates a ratio of distal
coronary pressure to aortic pressure measured during maximal hy- The nursing care of patients both during and after cardiac
peremia or vasodilatation (when minimal resistance is present catheterization is directed toward the prevention and detection of
across both the epicardial and microvascular beds), reflecting my- complications. The risk of a major complication (myocardial in-
ocardial perfusion. A pressure wire is placed across the suspected farction, death, or major embolization) during diagnostic cardiac
lesion and an adenosine infusion is administered. Normal FFR is catheterizations is below 1%.
1.0; a value less than 0.75 is abnormal and associated with abnor- The risk of an adverse event is dependent on individual co-
mal stress tests and inducible myocardial ischemia. Revasculariza- morbidities, cardiovascular anatomy, and type of procedure. Se-
tion is recommended for coronary lesions with an FFR less than vere peripheral vascular disease is a risk factor for major compli-
0.75. 31 cation with all procedures. The SCAI registry reported the
Adjunctive in-laboratory coronary physiological measure- incidence of complications during cardiac catheterization and
ments facilitate clinical decisions to treat or defer PCI or coronary coronary angiography: vascular complications, 0.43%; contrast
artery bypass graft surgery in patients who have intermediate reactions, 0.37%; MI, 0.05%; cerebrovascular accident, 0.07%;
stenoses. Decisions based on quantitative angiography have and mortality, 0.11%. 33