IN-VITRO VERSUS IN-VIVO ASSESSMENT OF VEIN WALL PROPERTIES

Venous compliance reflects the mechanical properties of the vein wall. Clinical methods of measurement have not been validated by comparison with the accepted in vitro measurement. Despite this, clinical assess ment of vein compliance may have a series of useful applications: (1) to assess the progression of chronic venous insufficiency and the rela ted hemodynamic forces acting on the saphenous vein wall; (2) to deter mine the suitability of the saphenous vein for replacement of an arter ial conduit by testing its mechanical properties; and (3) to select th e saphenous vein with preferable mechanical performance for coronary a rtery bypass. The aim of this study is to assess the relationship betw een in vitro and two in vivo methods of compliance measurement. Compli ance of the saphenous vein was determined in 20 patients, using both a n invasive and a noninvasive (A and B, respectively) method. Duplex sc anning was used for diameter measurement. Venous pressure was derived either intravenously with a needle transducer, or noninvasively with l imb length measurement. Patients underwent saphenous excision with fur ther in vitro compliance measurement of the same vein segment (method C). The compliance values obtained with the three methods showed diffe rent degrees of correlation (r= 0.516, p = 0.0001 for method A versus method C; r= 0.658, p = 0.0001 for method B versus method C; r= 0.993, p = 0.0001 for method A versus method B). The relationships with the in vitro measurements that were determined validate both in vivo metho ds for assessment of saphenous vein compliance. Due to its completely noninvasive design, method B appears to have potential use for clinica l assessment of saphenous vein wall properties.