血管内超声对血管内放射防治猪受损髂动脉狭窄形成的疗效观察

目的：通过血管内超声(IVUS)观察血管内放射(IR)对猪受损髂动脉形态学改变的影响，在体情况下探讨IR治疗对管腔重构的作用。方法：对中国小型猪髂动脉进行血管造影及IVUS检查后行球囊扩张损伤术。实验组通过置源管将高剂量铱—192(^192Ir)后装源对受损髂动脉施予总量为20Gy的IR治疗，而损伤对照组仅在受损髂动脉置入假源。动脉损伤后第28天时再次进行血管造影和IVUS检查。通过IVUS测量血管外弹力膜(EEM)横截面积、管腔横截面积检查、管腔最大径和最小径以及面积狭窄率和直径狭窄率。结果：IVUS检查发现，与损伤前相比，动脉损伤后28天时EEM与管腔横截面积以及管腔最小径均明显缩小（P〈0．05)，表明动脉受损后28天时发生明显负性重构(血管回缩)，导致了管腔明显狭窄；20GyIR后，管腔横截面积与管腔最小径均较损伤对照组明显增加(P〈0．05)，EEM横截面积也较对照组有所增加(但末达到统计学意义)，总量为20GyIR治疗使管腔狭窄显著减轻。结论：IUVS检查证实：负性重构是猪髂动脉球囊损伤后狭窄形成的重要原因；20GyIR可明显减轻动脉内膜损伤后狭窄形成，IR防治受损动脉狭窄形成的原因可能与改善血管负性重构有关。

Effect of Intravascular Radiation on Preventing from Stenosis after Arterial Injury through Observation of Intravascular Ultrasound

Objective: To evaluate the morphological changes in injured arterial wall in treatment with intravascular radiation(IR) by intravascular ultrasound(IVUS) and the effect of IR on vascular remodeling in vivo. Methods: After angiographies and IVUS examination on the left iliac arteries of 6 Chinese minipigs, the left iliac arterial injury was prepared by balloon overstretch. In radiation treating group(3 pigs), an iridium-192(192Ir) source with high dosage rate(HDR) afterloader was positioned at the injured iliac segments. In control group(3 pigs), only a afterloader catheter (without 192Ir source ) was positioned at the target segment. All pigs were examined by angiography and IVUS 28 days later. The extravascular elastic membrane (EEM) cross section area, lumen cross section area, maximal lumen diameter and minimal lumen diameter were measured by IVUS. Results: At the 28th day after arterial injury, the EEM cross section area, lumen cross section area and minimal lumen diameter measured by IVUS in control group were significantly decreased( P < 0. 05), and it was confirmed that there was an apparent nagetive modeling which resulted in narrowness of arteries 28 days after injury. Compared with the control group, lumen cross section area and minimal lumen diameter in 20 Gy IR group were obviously increased (P < 0. 05), and the EEM cross section area also enlarged but there was no statistical difference. IR treatment could significantly lessen the lumen stenosis after arterial injury. Conclusion: Through the examination of IVUS, negative remodeling is an important factor to cause narrowness after arterial injury. IR treatment with 20 Gy can obviously relieve stenosis after balloon overstretch and its mechnism to prevent stenosis may be related to the inhibition of nagetive remodeling after arterial injury.