金沢大学附属病院【はじめに】ステントグラフト留置術の臨床応用に伴い,瘤の血栓化が得られたにもかかわらず瘤径が縮小しない症例の存在が明らかになってきた.また,これらの症例が再破裂の危険性が高い症例との報告も多い.本研究の目的は,ステントグラフト留置により血流が遮断された動脈瘤の内圧変化を連続的に測定し,本術式の遠隔期での成功と考えられる瘤径の縮小・瘤内圧の減少にもっとも有用なファクターを明らかにすることである.【対象及び方法】実験用ブタを用い,血流が遮断された動脈瘤の内圧変化を連続的に測定し,瘤径の変化と比較する.瘤内圧に影響を与えるファクターとしてendoleak無し,type I及びtype IIのendoleakの有する動脈瘤モデル,ステントグラフトの留置部位を種々設定し実験群を作成する.動脈血圧,瘤内圧は2channelのテレメトリー型圧センサーを体内に植え込み,術後6ケ月にわたり同時に連続的に測定する.また,以上の実験結果によりステントグラフトの問題点を改善し,これをendoleak無し,type I及びtype IIのendoleakの有する動脈瘤モデルに留置する.犠牲死さぜ,瘤内の血栓の性状,瘤壁の病理学的検索もあわせ施行する.【結果】体血圧と瘤内圧とは,endoleakの有無とに有意な相関関係があった。また,landing zoneの長さにかかわらず,血管造影でendoleakが認められない場合は,瘤内圧は体血圧に比し有意に低下した,EndoleakType1,Type2ともに瘤内圧は体血圧に比し急性期には有意に低下していた.しかし,Type2のendoleakが遠隔期に残存しているcaseでは瘤内圧と体血圧に有意な差はなく,赤色血栓が認められた.【考察と結論】ステントグラフト留置術後に数ケ月間にわたり体血圧・瘤内圧を同時測定し瘤経との関係についての報告はなく,本研究により瘤径と体血圧,瘤内圧の関係が明らかにされた.Endoleakは急性期には瘤内圧を上昇させるものではないが,血管造影上大きな変化はなくても,瘤内圧の上昇が認められた.Endoleakが6ケ月以上継続する場合は早期に手術にconversionすべきと考える.[Introduction] There are, in accordance with clinical use of stent graft placement, cases in which aneurysm size is not reduced despite the aneurysm being thrombosed. In addition, these cases are often reported to involve a high risk of secondary rupture. The aim of this study was to continuously measure excluded sac pressure changes in an aneurysm in which blood flow had been blocked by stent graft placement and to clarify more useful factors for successful reduction of aneurysm size and decrease of excluded sac pressure within the aneurysm in the late stages of this procedure.[Subjects and methods] Excluded sac pressure changes in an aneurysm in which blood flow was blocked after stent graft placement were continuously measured using pigs, and changes in aneurysm size were compared. An aneurysm model with no endoleaks and type I and type II endoleaks was created to indicate factors affecting internal pressure within the aneurysm. Arterial blood pressure and internal pressure within t he aneurysm were continuously measured simultaneously for 6 months postoperatively using a telemetric pressure sensor implanted in the body. In addition, the above experimental results allowed remediation of problems with the stent graft, and the graft was placed in an aneurysm model with no endoleaks and type I and type II endoleaks. In addition, the pigs were sacrificed, and the nature of the thrombus in the aneurysm was examined together with a pathological study of the aneurysmal wall. [Results] Systemic blood pressure and internal pressure within the aneurysm had a significant correlation to the thickness of the graft portion of the stent graft and the presence or absence of an endoleak. In addition, internal pressure within the aneurysm dropped significantly in comparison to systemic blood pressure when an endoleak was not found in angiography, regardless of the length of the landing zone. With both type I and type II endoleaks, excluded sac pressure within the aneurysm dropped significantly in comparison to systemic blood pressure in acute stages. In cases where an endoleak remained over the long-term, however, there was no significant difference in internal pressure within the aneurysm and systemic blood pressure, and a red thrombus was noted. [Discussion and Conclusion] No studies simultaneously measured systemic blood pressure and internal pressure within the aneurysm for several months after stent graft placement and reported on the relationship to aneurysm size, but this study clarified the relationship between aneurysm size and systemic blood pressure and internal pressure within the aneurysm. An endoleak did not cause internal pressure within the aneurysm to rise during acute stages, but a rise in internal pressure within the aneurysm was noted despite the lack of evidence of major changes in angiography. Treatment should be quickly converted to surgery when an endoleak continues for 6 months or longer.研究課題/領域番号:17591462, 研究期間(年度):2005 – 2006出典：研究課題「ステントグラフト留置後の瘤径変化に影響を与えるリスクファクターの解明」課題番号17591462（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-17591462/175914622006kenkyu_seika_hokoku_gaiyo/）を加工して作
