Kaneda Hideaki, Terashima Mitsuyasu, Takahashi Takefumi, Iversen Stein, Felderhoff Thomas, Grube Eberhard, Yock Paul G, Honda Yasuhiro, Fitzgerald Peter J
Shonan Kamakura General Hospital, Kamakura, Japan.
Am Heart J. 2006 Mar;151(3):726-9. doi: 10.1016/j.ahj.2005.05.011.
Previous long-term (>1 year) studies have suggested that saphenous vein bypass grafts (SVGs) undergo vascular remodeling similar to native coronary arteries. However, early morphologic stages of SVG remodeling have not been characterized in vivo.
Thirty SVGs were studied 12 months after implantation using an intravascular ultrasound automated pullback system. Intravascular ultrasound images were analyzed between 10 and 60 mm from the tip of the guide. Lumen area (LA), intima area (IA), and vessel area (VA, defined as the area within the outer border of a hypoechoic intimal layer) were computed at 3 cross sections: the minimum LA (MLA) site and the proximal and distal reference sites. Area changes (Delta) were calculated as the MLA site minus the average of the reference sites.
In this cohort, 70% of the MLA sites had a smaller VA than the average references. On average, MLA sites had significantly smaller VA (9.7 +/- 2.9 vs 10.7 +/- 3.2 mm2, P < .01) and larger IA (2.5 +/- 2.1 vs 1.2 +/- 1.3 mm2, P < .01) than at the reference sites. The relative contribution of DeltaVA (-1.0 +/- 1.4 mm2) and DeltaIA (1.3 +/- 1.3 mm2) to lumen compromise (-2.3 +/- 1.4 mm2) were 43% and 57%, respectively. On the other hand, simple linear regression analysis revealed a significant positive correlation between DeltaIA and DeltaVA (y = -1.7 + 0.52x, r = 0.50, P < .01).
Within the first year, the mechanism of lumen compromise in SVG is a combination of negative remodeling and intimal hyperplasia. Positive remodeling is seen in a minority of cases. However, the direction and extent of remodeling correlated with change in intimal thickness.
既往长期（>1年）研究提示，大隐静脉旁路移植血管（SVG）会经历与天然冠状动脉相似的血管重塑。然而，SVG重塑的早期形态学阶段尚未在体内得到明确。
使用血管内超声自动回撤系统对植入12个月后的30条SVG进行研究。在距导管尖端10至60毫米之间分析血管内超声图像。在3个横截面计算管腔面积（LA）、内膜面积（IA）和血管面积（VA，定义为低回声内膜层外边界内的面积）：最小LA（MLA）部位以及近端和远端参考部位。面积变化（Δ）计算为MLA部位减去参考部位的平均值。
在该队列中，70%的MLA部位的VA小于平均参考值。平均而言，MLA部位的VA（9.7±2.9 vs 10.7±3.2平方毫米，P<.01）明显小于参考部位，而IA（2.5±2.1 vs 1.2±1.3平方毫米，P<.01）明显大于参考部位。ΔVA（-1.0±1.4平方毫米）和ΔIA（1.3±1.3平方毫米）对管腔狭窄（-2.3±1.4平方毫米）的相对贡献分别为43%和57%。另一方面，简单线性回归分析显示ΔIA与ΔVA之间存在显著正相关（y = -1.7 + 0.52x，r = 0.50，P<.01）。
在第一年，SVG管腔狭窄的机制是负性重塑和内膜增生的组合。少数病例可见正性重塑。然而，重塑的方向和程度与内膜厚度的变化相关。
