The role of preexisting pathology in the development of neointimal hyperplasia in coronary artery bypass grafts.
OBJECTIVE
Saphenous vein grafts (SVG) used for coronary artery bypass surgery (CABG) often develop a gradual luminal narrowing over the first year due to neointimal hyperplasia (NH). Although the basic science of NH is well studied, our clinical understanding of this issue is limited. The purpose of this cohort study was to investigate clinical risk factors for NH by monitoring luminal narrowing within SVG using multichannel CT angiography (CTA).


METHODS
Thirty patients underwent CABG involving SVG (N = 44) and arterial grafts (N = 36). Patient variables were recorded and the baseline quality of each conduit determined intraoperatively by analyzing surplus segments for intima-media thickness ratio (IMT) by histology and matrix metalloproteinase-2 by enzyme-linked immunosorbent assay. Percent luminal narrowing (%LN) was calculated for each patent graft by comparing the CTA appearance on day 5 to a repeat study at 1 y.


RESULTS
Compared with arterial grafts, SVG showed significantly higher IMT at baseline (0.9 +/- 0.65 versus 0.22 +/- 0.17, P < 0.0001) and more %LN over the first year (6.9 +/- 7.5 versus 25.3 +/- 13.3% LN, P< 0.0001). Of all of the measured variables, the only significant predictors of %LN included baseline IMT (r = 0.58, P = 0.002) and matrix metalloproteinase-2 levels (r = 0.60, P = 0.002) in SVG.


CONCLUSIONS
The degree of NH at baseline, a phenomenon exclusive to SVG and not found in arterial grafts, was significantly related to the development of lumen loss in the conduit over the first year after CABG. The study of SVG using serial CTA may provide unique insights into the natural history of SVG remodeling and to identify factors that influence the long-term function of this conduit.
Kon
Zachary N
ZN
Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
White
Charles
C
Kwon
Michael H
MH
Judy
Jean
J
Brown
Emile N
EN
Gu
Junyan
J
Burris
Nicholas S
NS
Laird
Patrick C
PC
Brown
Talitha
T
Brazio
Phillip S
PS
Gammie
James
J
Brown
James
J
Griffith
Bartley P
BP
Poston
Robert S
RS
D000368:Aged; D015331:Cohort Studies; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology*; D006085:Graft Survival; D006801:Humans; D006965:Hyperplasia; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D012307:Risk Factors; D012501:Saphenous Vein / Q000000981:diagnostic imaging / Q000473:pathology / Q000637:transplantation*; D017539:Tunica Intima / Q000473:pathology