Chapter 7 Coronary Artery Bypass Graft Surgery[85]. The improved survival was limited to patients
who were insulin-dependent and received an IMA
graft during surgery.
Diabetic patients who are candidates for renal
transplantation may have a particularly strong indi-
cation for CABG, as 20–30% of these patients have
signifi cant CASHD [86,87].
CABG in patients with pulmonary disease,
COPD, or respiratory insuffi ciency
Postoperative respiratory dysfunction is com-
mon after CABG, and early extubation of pati-
ents after CABG is desirable. Longer periods of
mechanical ventilation may be necessary in some
patients who develop acute respiratory distress
syndrome (ARDS), and in such patients, lower
tidal volumes (6 mL/kg) should be considered
[88].
The most common cause of preoperative pulmo-
nary dysfunction is chronic obstructive pulmonary
disease (COPD). A history of COPD has been
reported as an independent risk factor for noso-
comial pneumonia in patients after CABG [91].
Severity of COPD appears related to postoperative
mortality, and patients with moderate-to-severe
COPD are at increased risk after CABG [89,90].
Properly identifying the high-risk COPD patient
is hampered by inconsistent reporting in the
literature of the forced expiratory volume in the
fi rst second (FEV 1 ) in this subgroup. High-risk
FEV 1 values range from less than 70% to less
than 50% of the predicted normal values and/or an
FEV 1 of less than 1.5 L in the literature. However,
FEV 1 levels as low as 1.0 L would not necessarily
disqualify a candidate for CABG [1]. Another indi-
cator of risk is the degree of hypercapnea and the
need for home oxygen therapy. Any elevated PCO 2
above the normal range on a preoperative arterial
blood specimen renders the patient at least in the
moderate-risk category, as does the need for home
oxygen [1,90].
Preoperative efforts at improving pulmonary
mechanics (i.e. incentive spirometer, bronchodila-
tion, smoking cessation, chest physiotherapy, and
antibiotics for lung infections) may diminish post-
operative complications [1].CABG in patients with end-stage renal
disease (ESRD)
CABG may be offered to patients on dialysis with
similar indications to patients without ESRD [1].
Dialysis patients are at increased but acceptable risks
of perioperative mortality and morbidity (mediasti-
nitis and stroke) after CABG, and CABG in these
patients offers an increase in the quality of life for
long-term survivors [1,92].Valve disease
Class I
Patients undergoing CABG who have severe aortic
stenosis (mean gradient greater than or equal to
50 mm Hg or Doppler velocity greater than or equal
to 4 m/s) who meet the criteria for valve replace-
ment should have concomitant aortic valve replace-
ment (AVR). (Level of Evidence: B)Class IIa
1 For a preoperative diagnosis of clinically signifi -
cant mitral regurgitation, concomitant mitral cor-
rection at the time of coronary bypass is probably
indicated. (Level of Evidence: B)
2 In patients undergoing CABG who have moderate
aortic stenosis and are at acceptable risk for aortic
valve replacement (mean gradient 30–50 mm Hg or
Doppler velocity 3–4 m/s) concomitant aortic valve
replacement is probably indicated. (Level of Evidence:
B)Fig. 7.3 Improved survival with coronary artery bypass graft
surgery (CABG) versus percutaneous transluminal coronary
angioplasty (PTCA) in patients with diabetes mellitus. Results from
the Bypass Angioplasty Revascularization Investigation (BARI)
showing that patients with multivessel coronary disease who were
being treated for diabetes at baseline had a signifi cantly better
survival after coronary revascularization with CABG (solid curve)
than with PTCA (dashed curve) (P = 0.003). Modifi ed with
permission from Circulation. 1997;96:1761–9.