Fragmented QRS陽性の冠動脈疾患症例における2Dスペックルトラッキングエコー法の左室心筋ストレインを用いた心筋障害検出—遅延造影MRIを用いた検討—

Naka Saito; 齊藤 央; Shingo Kato; 加藤 真吾; Ayumi Tanaka; 田中亜由美; Takako Ishikawa; 石川 貴子; Kozue Nakagomi; 中込こず恵; Noritaka Saito; 斉藤 紀隆; Mamiko Nakamura; 中村満美子; Kazuki Fukui; 福井 和樹

Fragmented QRS陽性の冠動脈疾患症例における2Dスペックルトラッキングエコー法の左室心筋ストレインを用いた心筋障害検出—遅延造影MRIを用いた検討—Detection of Myocardial Scarring by Strain Analysis Using 2D Speckle Tracking Echocardiography in CAD Patients with Fragmented QRS Complex —Comparative Study with LGE MRI—

齊藤央¹，加藤真吾^3,4，田中亜由美¹，石川貴子¹，中込こず恵¹，斉藤紀隆¹，中村満美子¹，福井和樹²Naka Saito¹, Shingo Kato^3,4, Ayumi Tanaka¹, Takako Ishikawa¹, Kozue Nakagomi¹, Noritaka Saito¹, Mamiko Nakamura¹, Kazuki Fukui²

¹ 神奈川県立循環器呼吸器病センター検査科Department of Clinical Laboratory, Kanagawa Cardiovascular and Respiratory Center

² 神奈川県立循環器呼吸器病センター循環器内科Department of Cardiology, Kanagawa Cardiovascular and Respiratory Center

³ 横浜市立大学循環器・腎臓内科学教室Department of Medical Science and Cardiorenal Medicine, Yokohama City University Hospital

⁴ Department of Cardiology, Beth Israel Deaconess Medical CenterDepartment of Cardiology, Beth Israel Deaconess Medical Center

受付日：2015年8月25日Received: August 25, 2015

受理日：2016年2月21日Accepted: February 21, 2016

発行日：2016年6月1日Published: June 1, 2016

目的：Fragmented QRS（fQRS）陽性の冠動脈疾患（CAD）症例を対象とし，2Dスペックルトラッキング法による心筋ストレイン解析の心筋障害検出能を遅延造影（LGE）MRIを用いて検討すること．

対象と方法：fQRS陽性のCAD患者72名とコントロール群22名に，心エコー図検査と遅延造影MRI検査を行った．3方向の心筋ストレイン（longitudinal strain: LS; circumferential strain: CS; radial strain: RS）を定量的に評価した．LGE MRIで高信号域を認めた場合に心筋障害陽性と定義し，LGE陽性群（n＝54），LGE陰性群（n＝18），およびコントロール群（n＝22）の3群間で各心筋ストレイン値を比較し，心筋ストレインのLGE陽性セグメントの検出能をROC解析で評価した．

結果と考察：LSはLGE陽性群がLGE陰性群より有意に低値であった（−16.2±3.5 vs −19.3±3.4, p＜0.01）．CSおよびRSは，LGE陽性群とLGE陰性群で有意差はなかったが（CS: −24.4±7.3 vs −28.3±6.4, p＝0.084; RS: 31.8±13.3 vs 40.3±17.8, p＝0.086），LGE陽性群でコントロール群より有意に低値であった（CS: −24.4±7.3 vs −31.3±4.5, p＜0.01; RS: 31.8±13.3 vs 47.8±14.0, p＜0.01）．LGE陰性群とコントロール群間ではいずれのストレインも有意差はなかった（LS: −19.3±3.4 vs −20.6±2.1, p＝0.41; CS: −28.3±6.4 vs −31.3±4.5, p＝0.31; RS: 40.3±17.8 vs 47.8±14.0, p＝0.24）．ROC解析によるLGE陽性セグメントの検出能は，LSが最も優れていた（Area under the ROC curve; LS: 0.812, CS: 0.648, RS: 0.622）．

結論：fQRS陽性のCAD患者において，LSはLGE陽性群で陰性群に比較し有意に低値であった．またLSのLGE検出能はCSやRSと比較して優れていた．LSはfQRS陽性のCAD症例における微小な心筋障害を非侵襲的に検出できる可能性があることが示唆された．

Purpose: The aim of this study was to assess the detectability of strain analysis by 2D speckle tracking echocardiography (2D-STE) for myocardial scarring on late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) in coronary artery disease (CAD) patients with fragmented QRS complex (fQRS).

Subjects and Methods: We studied 72 CAD patients with fQRS and 22 control subjects. All study subjects underwent echocardiography and LGE MRI examinations. We defined myocardial scarring to be positive if patients had a high signal intensity area on the LGE MRI. Quantitative assessment of myocardial strain was performed in 3 directions (longitudinal strain, LS; circumferential strain, CS; and radial stain, RS). We compared myocardial strain between 3 groups (CAD patients with LGE, n＝54; CAD patients without LGE, n＝18; control subjects, n＝22). A receiver operating characteristic (ROC) curve was generated to assess the diagnostic accuracy of strain measurements by 2D-STE for the detection of myocardial scarring on LGE MRI.

Results: LS was significantly reduced in CAD patients with LGE compared to those without (−16.2±3.5 vs −19.3±3.4, p＜0.01). CS and RS were not significantly reduced in CAD patients with LGE compared to CAD patients without LGE (CS: −24.4±7.3 vs −28.3±6.4, p＝0.084; RS: 31.8±13.3 vs 40.3±17.8, p＝0.086) but CS and RS were reduced in comparison to control subjects (CS: −24.4±7.3 vs −31.3±4.5, p＜0.01; RS: 31.8±13.3 vs 47.8±14.0, p＜0.01). No significant difference was found in any strain between CAD patients without LGE and control subjects (LS: −19.3±3.4 vs −20.6±2.1, p＝0.41; CS: −28.3±6.4 vs −31.3±4.5, p＝0.31; RS: 40.3±17.8 vs 47.8±14.0, p＝0.24). The area under the ROC curve was substantially higher in LS compared to the areas of CS and RS (areas under the ROC curve: LS, 0.812; CS, 0.648; RS, 0.622).

Conclusion: In CAD patients with fQRS, LS was significantly reduced in LGE positive patients in comparison to LGE negative patients and controls. The area under the ROC curve of LS was larger than the areas of CS and RS, suggesting that the measurement of LS might be useful to detect even tiny myocardial abnormalities in CAD patients with fQRS.

Key words: fragmented QRS complex; 2-dimensional speckle tracking echocardiography; myocardial strain; late gadolinium enhancement; cardiovascular magnetic resonance imaging

超音波検査技術

原著Original Article