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Influence of Diabetes on Long-TermCoronary
Artery Bypass Graft Patency
JACC: Journal of the American College of Cardiology
Take-home message
•
This retrospective study looked into the impact of diabetes on graft patency fol-
lowing coronary artery bypass grafting. The stability of internal thoracic artery
(ITA) grafts was similar among patients with and without diabetes; there were no
significant differences at 1, 5, 10, and 20 years of follow-up. Conversely, the patency
of saphenous vein grafts at 1, 5, 10, and 20 years decreased in both patients with
diabetes (78%, 70%, 57%, and 42%, respectively) and without diabetes (82%, 72%,
58%, and 41%, respectively). Following adjustment for patient characteristics, early
ITA patency was significantly higher for patients with diabetes (OR, 0.63), although
there were no significant differences in late patency. After adjustments, there were
no significant differences in early or late saphenous vein grafts between patients
with and without diabetes.
•
The authors concluded that, contrary to their expectations, the long-term patency
of bypass grafts was not affected by diabetes, and the excellent long-term patency
of ITA grafts indicates that their use should be maximized in coronary artery bypass
patients, regardless of diabetes status.
Abstract
BACKGROUND
Nearly 50% of patients undergoing
coronary artery bypass grafting have diabetes.
However, little is known about the influence of
diabetes on long-term patency of bypass grafts.
Because patients with diabetes have more
severe coronary artery stenosis, we hypothe-
sized that graft patency is worse in patients with
than without diabetes.
OBJECTIVES
This study sought to examine the
influence of diabetes on long-term patency of
bypass grafts.
METHODS
From 1972 to 2011, 57,961 patients
underwent primary isolated coronary artery
bypass grafting. Of these, 1,372 pharmacolog-
ically treated patients with diabetes and 10,147
patients without diabetes had 15,887 postoper-
ative angiograms; stenosis was quantified for
7,903 internal thoracic artery (ITA) grafts and
20,066 saphenous vein grafts. Status of graft
patency across time was analyzed by longitudi-
nal nonlinear mixed-effects modeling.
RESULTS
ITA graft patency was stable over time
and similar in patients with and without diabe-
tes: at 1, 5, 10, and 20 years, 97%, 97%, 96%,
and 96% in patients with diabetes, and 96%,
96%, 95%, and 93% in patients without diabe-
tes, respectively (early p = 0.20; late p = 0.30). In
contrast, saphenous vein graft patency declined
over time and similarly in patients with and with-
out diabetes: at 1, 5, 10, and 20 years, 78%, 70%,
57%, and 42% in patients with diabetes, and 82%,
72%, 58%, and 41% in patients without diabetes,
respectively (early p < 0.002; late p = 0.60). After
adjusting for patient characteristics, diabetes was
associated with higher early patency of ITA grafts
(odds ratio: 0.63; 95% confidence limits: 0.43 to
0.91; p = 0.013), but late patency of ITA grafts was
similar in patients with and without diabetes (p =
0.80). Early and late patency of saphenous vein
grafts were similar in patients with and without
diabetes (early p = 0.90; late p = 0.80).
CONCLUSIONS
Contrary to our hypothesis, dia-
betes did not influence long-term patency
of bypass grafts. Use of ITA grafts should be
maximized in patients undergoing coronary
artery bypass grafting because they have
excellent patency in patients with and without
diabetes even after 20 years.
Influence of diabetes on long-term coronary
artery bypass graft patency.
J Am Coll Cardiol
2017 Aug 01;70(5)515-524, S Raza, EH Black-
stone, PL Houghtaling, et al.
www.practiceupdate.com/c/56306COMMENT
By Benjamin Morgan Scirica
MD
T
his retrospective analysis from
the Cleveland Clinic evaluated
bypass graft patency in almost
15,000 patients with and without diabe-
tes. Overall, arterial grafts demonstrated
excellent patency (>93% patency at 20
years) compared with vein grafts (~40%
at 20 years). To the surprise of the inves-
tigators, there was no difference in the
rates of patency for either arterial or
venous grafts between patients with
and without diabetes. Given the under-
lying biology of diabetes and vascular
disease, and the higher overall mortality
in patients with diabetes, this seemingly
paradoxical result raises the possibility
that there is an inherent bias in the way
patients were included in analysis, or of
residual confounding. For example, were
a greater number of healthier, asympto-
matic patients with diabetes referred
for follow-up catheterization due to the
concern of progression whereas only
symptomatic patients without diabetes
were referred for follow-up angiography?
Due to these potential limitations, I remain
somewhat skeptical about the conclusion
that patients with and without diabetes
have similar graft patency. The principal
message is that single arterial conduits
have remarkable patency, almost a “life-
long warranty,” and therefore should be
utilized for revascularization of the most
critical area of risk.
Dr Scirica is Cardiologist
and Director, Inovation,
Cardiovascular Division,
Brigham and Women’s
Hospital; Associate
Professor of Medicine,
Harvard Medical School;
Senior Investigator, TIMI
Study Group, Boston,
Massachusetts.
CARDIAC PROCEDURES & SURGERIES
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VOL. 2 • NO. 2 • 2017