The AHA Guidelines and Scientifi c Statements Handbook
approach and timing of surgery may be altered.
(Level of Evidence: C)
Recent antecedent cerebrovascular
accident (CVA)
Occurrence of a recent, preoperative CVA presents
a situation where delay in CABG may reduce peri-
operative neurologic risk [1]. A hemorrhagic com-
ponent to the CVA is particularly important, as
extension of the injury can result from hepariniza-
tion required for CABG [18]. It is generally believed
that a delay of 4 weeks or more is prudent if symp-
toms and coronary anatomy permit [1].
CPB time and neurologic risk
Increased time on CPB is associated with greater
neurologic risk. Patients without neurologic injury
have shorter pump times than those who develop
stroke and/or type 2 events [19].
Carotid disease and neurological risk reduction
Class IIa
1 Carotid endarterectomy is probably recom-
mended before CABG or concomitant to CABG in
patients with symptomatic carotid stenosis or in
asymptomatic patients with unilateral or bilateral
internal carotid stenosis of 80% or more. (Level of
Evidence: C)
2 Carotid screening is probably indicated in the
following circumstances: age greater than 65, left
main coronary stenosis, peripheral vascular disease,
history of smoking, history of transient ischemic
attack (TIA) or CVA, or a carotid bruit on physical
examination. (Level of Evidence: C)
Hemodynamically signifi cant carotid stenoses are
associated with as many as 30% of postoperative
strokes [20]. These strokes occur commonly on the
second to ninth postoperative day during an appar-
ent smooth postoperative recovery [21]. In the
cardiac surgery population, up to 22% of patients
have 50% carotid stenosis, and up to 12% have 80%
carotid stenosis [22]. Perioperative stroke risk is 2%
when carotid stenoses are less than 50%, 10% when
stenoses are 50–80%, and 11–18.8% when carotid
stenoses are greater than 80% [14,23].
Carotid endarterectomy done before or concomi-
tant with CABG carries a low mortality (3.5%),
reduces early postoperative stroke risk to less than
4%, and confers a 10-year rate of freedom from
stroke of 88% to 96% [24,25]. The staged approach
to carotid and CABG is most commonly employed,
with carotid endarterectomy preceding CABG [1].
Postoperative care after carotid surgery occurs in a
telemetry setting, with CABG following in 1 to 5
days later [1]. The superiority of combined versus
staged has not been established by prospective trials.
Stroke risk appears to be increased with a reversed-
stage procedure, with CABG preceding carotid end-
arterectomy [26]. The reversed-stage procedure
should be reserved for the uncommon patient with
a true CABG emergency [1].Other techniques to reduce neurologic risk
Since the number of microemboli delivered during
an operation using CPB correlates with postopera-
tive neurologic decline [27], the use of a 40-micron
arterial line fi lter appears to be protective. Rou-
tine use of the membrane oxygenator over the
bubble oxygenator is also encouraged [19,28,29].
The return of shed mediastinal blood to the CPB
circuit via cardiotomy suction may increase the
microembolic load to the brain [1]. OPCAB may
reduce the incidence of neurologic injury by avoid-
ing aortic manipulation [30], but reports have been
mixed [31,32]. Alpha-stat acid/base management
during CPB appears to be benefi cial over pH-stat for
CABG [31]. Finally, avoidance of cerebral hyper-
thermia [1], keeping blood return temperature
below 38°C during rewarming [1], and maintaining
serum normoglycemia are important adjuncts
[1,35,36].Reducing risk of perioperative myocardial
dysfunction
Myocardial protection for patients with
satisfactory preoperative cardiac function
There are a number of acceptable techniques associ-
ated with excellent results for the majority of pati-
ents undergoing CABG, and this is especially true in
the case of normal, or preserved left ventricular
function [1].Myocardial protection for patients with acutely
depressed cardiac function
Class I
Blood cardioplegia should be considered in patients
undergoing CPB accompanying urgent/emergent