Recommendations

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Smith et al. 2005
ACC/AHA/SCAI Practice Guidelines
9
Complications associated with PCI are similar to those
resulting from diagnostic cardiac catheterization, but their
prevalence is more frequent. Complications have been categorized
as major (death, MI, and stroke) or minor (transient
ischemic attack, access site complications, renal insufficiency,
or adverse reactions to radiographic contrast). Additional
specific complications include intracoronary thrombosis,
coronary perforation, tamponade, and arrhythmias.
Reported rates for death after diagnostic catheterization
range from 0.08% to 0.14%, whereas analyses of large registries
indicate overall unadjusted in-hospital rates for PCI of
0.4% to 1.9% (Table 3) (41-52). This range is greatly influenced
by the clinical indication for which PCI is performed,
with the highest mortality rates occurring among patients
with STEMI and cardiogenic shock. Death in such patients
may not be a direct result of the PCI procedure but rather a
consequence of the patient’s underlying illness. For example,
in a combined analysis of PCI as primary reperfusion therapy
for STEMI, the short-term mortality rate was 7% (53).
Even after exclusion of patients with cardiogenic shock, inhospital
mortality was 5%.
Myocardial infarction can be a direct result of PCI, most
commonly due to abrupt coronary occlusion or intracoronary
embolization of obstructive debris. Determining and comparing
the incidence of MI after PCI is difficult because the
definition of MI as a result of PCI is controversial. The conventional
definition requires 2 of the following: a) prolonged
chest discomfort or its equivalent; b) development of pathologic
Q waves; and c) rise in serum cardiac biomarkers above
a critical level. Rates of periprocedural MI using this definition
have ranged from 0.4% to 4.9%. Using a consistent definition
for MI, the incidence of this complication has
declined approximately 50% with the routine use of intracoronary
stents (21,21a,50).
More recently, an isolated rise and fall in either CK-MB or
troponin is considered to be a marker of myocardial necrosis
(21). The relationship between cardiac biomarker elevation
and myocardial cell death and evidence of subendocardial
infarction on magnetic resonance imaging (MRI) support
this position (54,55). Furthermore, large rises in cardiac biomarkers
are associated with an increased risk for late death
(26,56,57). Whether death in such patients is a consequence
of the myonecrosis or a marker of patients who are at
increased risk for death because of more advanced coronary
disease is unclear. Complicating our understanding of the
implications of this definition is the very frequently observed
mild to modest elevation of serum CK-MB among patients
with apparently uncomplicated PCI. When troponin is measured
after PCI, more than 70% of patients exhibit elevated
values after an otherwise successful intervention (58). Such
patients may have no symptoms or electrocardiographic
(ECG) abnormalities to suggest ischemia yet are “enzyme
positive.” One study has suggested a postprocedural increase
in troponin T of 5 times normal is predictive for adverse
events at 6 years. The long-term prognostic significance of
smaller postprocedural troponin T elevations awaits further
investigation (27) (Table 2) (26-40).
Another study indicated that more extensive stent expansion
resulted in CK release but did not increase adverse cardiac
events (59). Accordingly, it is important to acknowledge
that the significance of mild biomarker rises after clinically
successful PCI should be distinguished from situations
wherein patients experience an unequivocal “clinical” infarction
manifested by chest pain and diagnostic ECG findings
(60).
Routine measurement of CK-MB is advocated by some
(21) and actually mandated by certain healthcare systems. In
this regard, the current Committee supports the recommendations
of the 2001 Guidelines and recommends that all
patients who have signs or symptoms suggestive of MI during
or after PCI and those with complicated procedures
should have CK-MB and troponin I or T measured after the
procedure. In addition, the Committee recommends that routine
measurement of cardiac biomarkers (CK-MB and/or troponin
I or T) in every patient undergoing PCI is reasonable 8
to 12 h after the procedure. In such patients, a new CK-MB
or troponin I or T rise greater than 5 times the upper limit of
normal would constitute a clinically significant periprocedural
MI.
The need to perform emergency coronary artery bypass
surgery (CABG) has been considered as a potential complication
of PCI. Typically, CABG is performed as a rescue
revascularization procedure to treat acute ischemia or infarction
resulting from PCI-induced acute coronary occlusion. In
the era of balloon angioplasty, the rate of emergency CABG
was 3.7% (49). In a more contemporary time period, with the
availability of stents, the reported rate was 0.4% among a
similar cohort of patients.
Various definitions have been proposed for stroke. A common
feature to definitions has been a loss of neurologic function
of vascular cause that lasts more than 24 h. More recently,
attention has been directed to refining the definition of
transient ischemic attack (TIA), which indirectly broadens
that of stroke (61). The time-based definition of a TIA is a
sudden, focal neurologic deficit that lasts less than 24 h that
is of presumed vascular origin and confined to an area of the
brain or eye perfused by a specific artery. The new definition
of TIA is a brief episode of neurologic dysfunction caused by
brain or retinal ischemia, with clinical symptoms typically
lasting less than 1 hour and without evidence of infarction.
Presence of cerebral infarction by imaging techniques constitutes
evidence of stroke regardless of the duration of
symptoms.
Bleeding is a complication of increasing concern with the
more frequent use of potent antithrombin and antiplatelet
agents. A frequently used definition for bleeding developed
by the TIMI group includes classification as major, moderate,
or minor. Major bleeding is defined as intracranial,
intraocular, or retroperitoneal hemorrhage or any hemorrhage
requiring a transfusion or surgical intervention or that
results in a hematocrit decrease of greater than 15% or hemoglobin
decrease of greater than 5 g per dL (62). Episodes of
hemorrhage of lesser magnitude would fall into the moder-