頸部頸動脈狭窄病変に対する頸部超音波検査 : PTA/STENT治療の安全性の予測  [in Japanese] Usefulness of Ultrasonography for Neck Carotid Artery Stenosis Lesion  [in Japanese]

近年PTA/STENT治療の適応は, 頸部頸動脈内膜剥離術(CEA)が困難な症例などに拡大されてきている. しかしPTA/STENT治療には, 依然としてdistal embolismによる合併症の問題が残されている. 今後, PTA/STENTの手技をより安全に行っていくためには, 頸部plaqueの術前診断により適応を厳密にしていく必要がある. 頸部plaqueを非侵襲的に診断するために, 主に頸部エコー検査が行われており, この数年で診断精度が向上してきた. しかし, 頸動脈狭窄疾患の予後を判断する十分なデータが出ているとはまだいえない. これまでに頸部エコー検査をPTA/STENTの術前診断のひとつとして位置付けてある報告はみられる. しかし, 頸部エコーのPTA/STENTの術前検査としての信頼性について検討した報告はみられない. 今回われわれは, 頸動脈plaqueのエコー所見と術中肉眼所見を比較して, 頸部エコー検査による性状診断の精度が, PTA/STENTの術前検査として十分であるかを検討した.

The recent advancement of ultrasonographic imaging equipment has provided accurat,e visualization and characterization of the intimal plaques of the cervical carotid arteries. Because the soft plaques may easily cause embolic occlusion of the distal cerebral arteries during manipulat,ion of the stenotic carotid art,eries, it is important to predict the character of the carotid plaques for the safe PTA/STENT procedures. In this study, we examined patients who underwent carotid endarterectomy (CEA) with ultrasonographic imagings preoperatively. The macroscopic findings of the obtained carotid artery plaques and the preoperative ultrasonographic findings were compared to elucidate the diagnostic ability and clinical usefulness of the ultrasonography in this disorder. Twelve patients with 14 Iesions who underwent CEA were examined preoperatively by ultrasonography (TOSHIBA SSA370A, Iinear probe of 7.5 MHz). There were 10 men and 2 women, aged from 64 to 73 years. Ultrasonographic findings of t,he plaques could be classified as "hyper," "iso," "low" or "mixed" intensity by the character, and as "smooth" or "irregular" plaques by t=he configuration. The perioperative macroscopic findings of t.he plaques were charact,erized as "fragile" or "tough." The ultrasonography showed 3 lesions with low intensity and 4 lesions with mixed intensity, including low intensity. These 7 Iesions were fragile in the macroscopic findings. Five lesions showing iso intensity by the ultrasonography did not include fatty degenerat,ion or internal bleeding of the plaques and were judged as tough plaques. The ultrasonography was able to detect an ulcer of plaque. Micro embolisms such as the fat in plaque or the thrombus can occur in the operation, and it is said that the complications of the cerebral embolisms caused by t,hem are a serious problem of PTA. The exclusion of the high-risk group by ultrasonography examination is the most important factor in doing PTA/STENT safely. From the findings by ultrasonography and the perioperative macroscopy, we can classify "safety" or "danger" in each plaque to perform PTA/STENT. We judged the fragile plaques too dangerous for PTA/STENT. We can fully satisfy the character diagnosis of the carotid plaques by ultrasonography in estimating the safeness for the intravascular operation. The probability that complications by micro embolisms occur will be high when performing PTA/STENT in low-intensity plaques. We should exclude such cases from indication of PTA/STENT in future.