Print this pageEarly Remodeling Of Lower Extremity Vein Grafts: Correlation With Outcomes
Christopher D Owens, Nicole Wake, Lisamarie Fahy, Jeffrey Jacot, Marie Gerhard-Herman, Louis L Nguyen, Matthew T. Menard, Edwin C. Gravereaux, Michael Belkin, Michael S. Conte
Brigham and Women's Hospital, Boston, MA
Introduction:
The remodeling of vein bypass grafts is incompletely understood. We sought to examine patterns of adaptation in lower extremity vein grafts, and to assess their correlation with clinical outcomes.
Methods:
We conducted a prospective, longitudinal study of patients undergoing infrainguinal reconstruction with autogenous conduit. In addition to standard duplex surveillance, lumen diameter and pulse wave velocity (PWV) were assessed by ultrasound at surgery and at 1,3, and 6 months postoperatively. Graft dimensions and wall stiffness were correlated with clinical outcomes.
Results:
There were 88 patients and 91 limbs in this study. Graft failure occurred in 24 cases (22 revisions, 2 occlusions) with a mean reintervention time of 7.6 months. Vein graft lumen diameter increased during the first month of implantation, from 0.38±.01 to 0.43 ±0.02 cm, (mean±SEM;p=0.03). Vein grafts achieved 96% of their 6-month diameter within the first month. PWV increased from surgery to 6 months (15.9±.76 to 21.0±2 m/s;p=.004) reflecting a nearly 2.5-fold increase in conduit stiffness (1.2±.12 to 3.0±.98 x 106 dynes/cm;p=.0006). The greatest relative increase (25%) in PWV occurred from months 1-3. Over the first month of implantation, 74% of vein grafts increased lumen diameter by a mean of 26%. Grafts which failed to demonstrate an increase in lumen diameter over the first month had an association with subsequent failure (50% vs. 11.5%;p=0.027, Fisher’s Exact Test). Graft patency was also associated with a trend of lower PWV (less stiff) at one month, 17.1vs.20.9 m/s(p=0.08). Alternative conduit veins had similar diameters to GSV at the time of implantation (0.37vs.0.38), but larger diameters at 6 months (0.56vs.0.41 cm;p=.002).
Conclusion:
Vein graft remodeling appears to involve at least two distinct temporal phases. Outward remodeling occurs early, whereas biomechanical changes occur in a more delayed fashion. Early outward remodeling may be important for successful vein graft adaptation.