檜垣 里江子¹, 齋藤 実², 西尾 静子¹, 今井 美咲¹, 和氣 大輔¹, 河内 好子¹, 永尾 彰子¹, 諸藤 徹², 稲葉 慎二², 住元 巧²

Rieko HIGAKI¹, Makoto SAITO², Shizuko NISHIO¹, Misaki IMAI¹, Daisuke WAKE¹, Yoshiko KAWACHI¹, Akiko NAGAO¹, Toru MOROFUJI², Shinji INABA², Takumi SUMIMOTO²

¹喜多医師会病院生理検査室, ²喜多医師会病院循環器内科

¹Department of Physiological Laboratory, Kitaishikai Hospital, ²Department of Cardiology, Kitaishikai Hospital

キーワード : transthoracic Doppler echocardiography, proximal left coronary artery, machine dependency, sonographer dependency

目的：経胸壁ドプラ心エコー（transthoracic Doppler echocardiography: TTDE）による左冠動脈近位部血流計測は，同部の冠動脈病変の推定に有用である．本研究の目的は，その検出率と検出時間における機種および検者依存性の検討である．対象と方法：1）機種依存性　2010年から2016年までに，同一検者によりGE社のVivid7とVivid E9でTTDEが施行された連続患者325名を対象とした．2）検者依存性　同期間に，3名の検者により（検者1，検者2：TTDE経験5年，検者3：TTDE経験2年），同一患者にGE社のVivid7でTTDEが施行された連続患者100名を対象とした．両検討共に，対象としたTTDEの期間中に冠動脈バイパス術や左冠動脈近位部にインターベンションが行われた症例は除外した．左冠動脈近位部血流検出の定義は同部の血流速度波形を保存できた場合とし，検出時間の定義は通常の心エコー検査における最終画像保存時間から左冠動脈近位部血流の速度波形保存時間までとした．結果：1）機種依存性　検出率はVivid7に比し，Vivid E9で有意に良好であったが（60％ vs 68％，p＝0.01），検出時間は両機種間に有意差を認めなかった（73秒vs 72秒，p＝0.10）．2）検者依存性　検出率は各検者間で有意差を認め（検者1：77％，検者2：70％，検者3：65％，p＝0.0486），検者1と検者3の間に差を認めた（p＝0.03）．また，検出時間も検者間差を認め（検者1：57秒，検者2：65秒，検者3：86秒，p<0.01），検者3と他の検者間に有意差を認めた．結論：左冠動脈近位部血流検出には機種および検者依存性が存在することが示唆された．また，検者依存性はTTDEの習熟度に関連する可能性が示唆された．

Purpose: Proximal left coronary artery (LCA) lesions are associated with poor prognosis. Transthoracic Doppler echocardiography (TTDE) can be performed in a short time and combined with routine echocardiography. Further, the accelerated coronary flow velocity detected by TTDE reflects the presence of proximal LCA lesions with high specificity. Confirming its reproducibility is crucial for quality control. We aimed to retrospectively investigate machine and sonographer dependence for detecting coronary flow at the site of the proximal LCA. Subjects and Methods: 1)Machine dependency We enrolled 325 consecutive patients who underwent two rounds of TTDE using two different echo machines (Vivid 7 and Vivid E9; GE Vingmed, Horten, Norway) by the same sonographers between 2010 and 2016. 2)Sonographer dependency We enrolled 100 consecutive patients who underwent three TTDE examinations using the same echo machine (Vivid 7) by three sonographers with different levels of TTDE experiences (sonographer 1 and 2: 5 years, sonographer 3: 2 years) between 2010 and 2016. In both studies, the definition of detecting coronary flow at the proximal LCA was the successful digital image acquisition of coronary flow via the pulse Doppler method at that site. If coronary flow was detected, the time for the detection was also analyzed. Patients with revascularization during the period of TTDE examinations were excluded. Results: The detection rate of coronary flow using the Vivid E9 was significantly better than that of the Vivid 7 (68% vs 60%, p=0.01). However, the detection time was not different between the two machines. Also, sonographer dependency for the detection rate (sonographer 1: 77%, sonographer 2: 70%, sonographer 3: 65%, p=0.0486) and the detection time (sonographer 1: 57 sec, sonographer 2: 65 sec, sonographer 3: 86 sec, p<0.01) was observed, which might be associated with TTDE experience. Conclusion: The detection of coronary flow at the proximal LCA may depend on the echo machine and sonographer. Additionally, a learning curve may exist for its detection.