磁共振增强血管成像对主动脉缩窄术后再狭窄评估

Evaluation of restenosis after aortic coarctation repair using contrast enhanced-meganetic resonace-angiography

目的:使用MRI增强血管成像序列(MRA)对主动脉缩窄(CoA)术后再狭窄患者进行检查,评估主动脉弓形变和血流动力改变的关系。方法:39例CoA术后再狭窄患儿经超声心动图测量主动脉弓跨狭窄处流速(FR)和压差(PG)明确诊断。所有患儿行MRA检查,测量升主动脉、主动脉弓、再狭窄及狭窄后扩张段及降主动脉横膈水平直径,计算升主动脉/降主动脉(A/d)、主动脉弓/降主动脉(Ar/d)、再狭窄/降主动脉(R/d)、狭窄后扩张段/降主动脉(D/d)比值。结果:根据R/d将患儿分为轻、中、重度狭窄3组,三组患儿A/d、Ar/d、D/d、FR及PG值均无统计学差异。R/d与FR、PG存在中等程度负相关(FR:r=-0.34,P=0.04;PG:r=-0.40,P=0.01)。38.46%患儿存在主动脉弓成角畸形,该组患儿D/d明显增高(t=-2.90,P=0.01),Ar/d减低(t=2.90,P=0.01)。35.90%合并主动脉弓发育不良,这组患者FR及PG值偏高(FR:t=-2.03,P=0.05;PG:t=-1.97,P=0.05)。结论:CoA术后再狭窄程度与局部血流动力改变相关,部分患者合并主动脉成角、主动脉发育不良,导致血流动力异常更为明显,需要更紧密的关注。

Objective：Patients with restenosis after coarctation of aorta（CoA）repair underwent contrast enhanced-meganetic resonace-angiography（CE-MRA）,in order to evaluat the relationship between shape deformation and flow alteration.Methods：Post-operation CoA patients with restenosis were diagnosed by echocardiography,the flow rate（FR）and pressure gradient（PG）were measured.The aortic shape was characterized by MRA.The diameters of ascending aorta,aortic arch,the repair site and the dilated part distal to the surgical site were measured and the ratio to the descending aortic diameter at the diaphragm level were calculated,presented as A/d,Ar/d,R/d and D/d.Results：Patients were divided into three groups according to R/d：slight,moderate and severe stenosis.No significant difference was found in A/d,Ar/d,D/d,FR and PG among three groups.R/d had moderate negative correlation with FR and PG（FR：r=-0.34,P=0.04;PG：r=-0.40,P=0.01）.Angulated aortic arch was found in 38.46% who had higher D/d and lower Ar/d（D/d：t=-2.90,P=0.01;Ar/d：t=2.90,P=0.01）.The ratio of patients with aortic arch hypoplasia was 35.90%,and patients had higher FR and PG（FR：t=-2.03,P=0.05;PG：r=-1.97,P=0.05）in this group.Conclusion：Restenosis at the CoA repair site is associated with the flow changes.The clinical surveillance is necessitated for long term,especially for those with angulated and hypoplastic aortic arch.