Early remodeling of lower extremity vein grafts: inflammation influences biomechanical adaptation.
BACKGROUND
The remodeling of vein bypass grafts after arterialization is incompletely understood. We have previously shown that significant outward lumen remodeling occurs during the first month of implantation, but the magnitude of this response is highly variable. We sought to examine the hypothesis that systemic inflammation influences this early remodeling response.


METHODS
A prospective observational study was done of 75 patients undergoing lower extremity bypass using autogenous vein. Graft remodeling was assessed using a combination of ultrasound imaging and two-dimensional high-resolution magnetic resonance imaging.


RESULTS
The vein graft lumen diameter change from 0 to 1 month (22.7% median increase) was positively correlated with initial shear stress (P = .016), but this shear-dependent response was disrupted in subjects with an elevated baseline high-sensitivity C-reactive protein (hsCRP) level of >5 mg/L. Despite similar vein diameter and shear stress at implantation, grafts in the elevated hsCRP group demonstrated less positive remodeling from 0 to 1 month (13.5% vs 40.9%, P = .0072). By regression analysis, the natural logarithm of hsCRP was inversely correlated with 0- to 1-month lumen diameter change (P = .018). Statin therapy (beta = 23.1, P = .037), hsCRP (beta = -29.7, P = .006), and initial shear stress (beta = .85, P = .003) were independently correlated with early vein graft remodeling. In contrast, wall thickness at 1 month was not different between hsCRP risk groups. Grafts in the high hsCRP group tended to be stiffer at 1 month, as reflected by a higher calculated elastic modulus (E = 50.4 vs 25.1 Mdynes/cm2, P = .07).


CONCLUSIONS
Early positive remodeling of vein grafts is a shear-dependent response that is modulated by systemic inflammation. These data suggest that baseline inflammation influences vein graft healing, and therefore, inflammation may be a relevant therapeutic target to improve early vein graft adaptation.
Owens
Christopher D
CD
Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA.
Rybicki
Frank J
FJ
Wake
Nicole
N
Schanzer
Andres
A
Mitsouras
Dimitrios
D
Gerhard-Herman
Marie D
MD
Conte
Michael S
MS
D000222:Adaptation, Physiological; D000368:Aged; D000714:Anastomosis, Surgical / Q000009:adverse effects; D001132:Arm / Q000098:blood supply*; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D007383:Intermittent Claudication / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D007511:Ischemia / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D035002:Lower Extremity / Q000098:blood supply*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012039:Regional Blood Flow; D012501:Saphenous Vein / Q000473:pathology / Q000503:physiopathology / Q000637:transplantation*; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D014945:Wound Healing
D002097:C-Reactive Protein