Chapter 7 Coronary Artery Bypass Graft SurgeryCABG in acute coronary syndromes
Class I
If clinical circumstances permit, clopidogrel should
be withheld for 5 days before performance of CABG
surgery. (Level of Evidence: B)
Acute coronary syndromes (ACS) represent a
continuum from severe angina to acute MI. The
most recent nomenclature defi nes the spectrum of
ACS from unstable angina to non-ST-segment ele-
vation MI (NSTEMI) to ST-segment elevation MI
(STEMI). CABG offers a survival advantage over
medical therapy in patients with unstable angina
and LV dysfunction, particularly in those patients
with triple-vessel disease [1]. In patients with coro-
nary disease anatomy suitable for either PCI or
CABG as treatments, there is no survival advantage
of either treatment technique over the other [1].
Impact of evolving technology
Less-invasive CABG
OPCAB potentially offers less risk to the patient
undergoing CABG. Three randomized, prospective
trials have been reported comparing OPCAB and
standard CABG using CPB. None of these trials were
large enough to demonstrate any difference in oper-
ative mortality or the occurrence of postoperative
stroke [108–110]. Larger randomized trials will be
necessary to determine the subsets of patients receiv-
ing the most benefi t from OPCAB.
Robotics
Closed chest multiarterial bypass on the beating
heart would potentially offer the maximum benefi t
via the least invasive approach. The major obstacle
to a totally endoscopic approach to CABG has been
the technical diffi culty in the construction of an
accurate anastomosis.
Arterial and alternate conduits
Class I
In every patient undergoing CABG, the left IMA
should be given primary consideration for revascu-
larization of the LAD artery. (Level of Evidence: B)
Prospective angiographic studies from BARI docu-
mented an 87% 1-year vein patency rate compared
with 98% for the IMA. The prospective study of
vein graft patency noted a 66% patency rate at 10
postoperative years. Evidence that bilateral IMA
(BIMA) usage provides incremental patency benefi t
over IMA plus vein grafts has been diffi cult to fi nd.
Concerns regarding operative diffi culty, operative
length of time, and increased wound infection rates
have prevented universal acceptance of BIMA graft-
ing. The radial artery as a conduit has seen interest
in some centers. The potential for conduit vasospasm
with the radial when exposed to catecholamines has
caused some to avoid this strategy. Acar et al. reported
an 84% 5-year radial patency rate in 100 consecutive
patients receiving the radial artery as a bypass conduit
during CABG [11]. Long-term results of the gastro-
epiploic and inferior epigastric arteries are not avail-
able; however, these arteries have been used with
some success in the short term.Transmyocardial laser revascularization
Class IIa
Transmyocardial surgical laser revascularization
(TMLR), either alone or in combination with CABG
is reasonable in patients with angina refractory to
medical therapy who are not candidates for PCI or
surgical revascularization. (Level of Evidence: A)
The principal utility of TMLR is directed towards
patients with severe angina pectoris refractory to
medical therapy and who are unsuitable for surgical
revascularization, PCI, or heart transplantation.
These patients often have small, diffusely diseased
coronaries that are not amenable to CABG or PCI.
Five prospective, randomized, controlled trials have
demonstrated signifi cant improvement in angina
versus medical therapy with TMLR [112–116]. No
trial demonstrated a survival benefi t. The benefi cial
effects of TMLR seem to decline somewhat after one
year [117].Institutional and operator competence
Volume considerations
Studies suggest that survival after CABG is nega-
tively affected when carried out in institutions that
perform fewer than 100 cases annually [1].Report cards and quality improvement
Outcome reporting in the form of risk-adjusted
mortality rates after CABG has been effective in
reducing mortality rates nationwide [1]. Public
release of hospital and physician-specifi c mortality