Intravascular imaging devices can offer information about vessels that cannot be depicted by angiography. Intravascular ultrasound (IVUS) can image the trilaminar structure of vessel walls and not only enable quantitative analysis, but also tissue characterization by radiofrequency data analysis. Coronary angioscopy provides full color images as direct visualization of the coronary lumen, and the images are applicable to the macroscopic diagnosis of intracoronary structures. Optical coherence tomography (OCT) is a novel optical imaging technology that provides cross-sectional tomographic images that yield detailed structural information superior to any other currently available modality. These intravascular imaging devices have played an important role both in the elucidation of the pathology of coronary artery disease and in the guidance of clinical treatment. Rupture of atherosclerotic plaque and the overlying thrombus is often observed in culprit lesions of acute coronary syndrome (ACS). In vivo, intravascular imaging devices can show detailed morphology of the culprit lesion that is associated with the clinical presentation and the prognosis. Rupture-prone plaques are called “vulnerable plaques.” Identification of vulnerable plaques has been attempted over the years. Prospective studies have shown that thin cap fibroatheroma (TCFA), defined by different intravascular imaging devices, is related to future cardiac events. Furthermore, multiple vulnerable plaques are often observed in non–culprit arteries of ACS patients. Therefore, ACS is recognized to represent a pan-coronary process of vulnerable plaque development. In addition, the multiplicity of vulnerable plaques was also demonstrated to be a predictor of ACS events. Some cardiac biomarkers, which are reported to be predictors of ACS events, are associated with the characterization of culprit and non-culprit arteries in ACS patients. On the other hand, the detailed findings obtained by intravascular imaging devices play an important role to prove the validity of noninvasive coronary artery studies. Near-infrared spectroscopy and coronary thermography can reveal plaque vulnerability by detecting inflammation and by quantifying the molecular composition of the plaque. The introduction of new technologies will increase our understanding of the pathophysiology and prevention of ACS.

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【目的】非侵襲的検査法な冠動脈評価法であるmulti detector-row computed tomography(MDCT)は陰性的中率が約99%と極めて高く，MDCTで有意狭窄病変がなければ労作性狭心症はほぼ否定できる．そこで，MDCTで有意狭窄病変のない有意狭窄なし例の検出がMDCT施行前の諸検査から予測可能か検討を行った．【対象】2009年1月1日より12月31日までにMDCTを施行し，前後3カ月以内の血液検査よりlipid profileを評価できた96例を対象とした．Friedewaldの式よりLDLC(LDL-cholesterol)を算出し，LDLC/HDLC(HDL-cholesterol)およびFramingham risk score(FRS)を評価した．MDCTで75%以上の冠動脈狭窄の有無により2群に分け，比較を行った．【結果】年齢，性別，収縮期血圧，糖尿病有病率，喫煙率，血液検査所見には有意差を認めなかった．FRSは有意狭窄例で有意に高値であった(9.6±6.4%，13.3±7.2%，P<0.05)．有意狭窄例のFRSは6以上であり，FRS 6以下では全例が有意狭窄なし例であった．【結語】FRS 6以下は有意狭窄なし例であった．また，FRSは有意狭窄例で有意に高値であり，MDCTを施行する際には患者背景を複合的に評価する必要があると考えられた．

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Background: Coronary artery calcium is a superb marker for atherosclerosis. Measurement of the coronary artery calcium score (CACS), using computed tomography (CT), is useful for evaluating of coronary artery disease (CAD). CAD is the most frequent cause of death and morbidity in patients with diabetes. In Western countries, a CACS >400 in patients with diabetes is a strong predictor of CAD. However, the optimal CACS cutoff point for patients with diabetes, especially in the Japanese population, is unclear. Methods: We enrolled 304 patients (188 male, mean age 64.0±11.4 years, DM n=116) who underwent 64-slice multidetector CT coronary angiography to evaluate of CAD. The CACS was calculated with the Agatston method and divided into seven categories: 0, 1 to 10, 11 to 100, 101 to 200, 201 to 400, 401 to 1000, and >1000. Significant stenosis was defined as ≥50% lumen reduction. The correlation between severity of CAD and each category of the CACS was evaluated. Results: We found a strong correlation between severity of CAD and the CACS (P<0.001). The CACS in diabetics was significantly higher than in non-diabetics (P=0.03). Receiver operating characteristic curve analysis demonstrated that a CACS >100 was the appropriate cutoff for recommending evaluation of CAD in both diabetics and non-diabetics. Conclusions: The CACS can be used to predict significant coronary stenosis in patients with diabetes, with a cutoff point of CACS >100 for recommending evaluation of CAD in both diabetics and non-diabetics.

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経皮的冠動脈形成術(PCI)の適応拡大により外科に紹介される患者は3枝病変，虚血性心筋症(ICM)や虚血性僧帽弁閉鎖不全症(IMR)合併例など複雑病変例が中心となってきた．低左心機能症例に対する外科治療成績について後方視的に検討した．低左心機能症例における我々の基本的治療方針は，（1）完全血行再建，（2）scheduled IABPや体外循環を使用し循環動態の安定を重視する，（3）2度以上のIMRについては僧帽弁形成術を追加する，（4）左室瘤に対しては左室形成術を，（5）弁膜症や大血管手術も同時に行う，である．2002年1月から2008年8月までに当科で施行したCABG症例513例のうち術前左室駆出率(LVEF)35%以下の症例70例(13.6%)を対象とした．術前のLVEFは28.6±5.8%から術後39.3±11.2%に改善した．左室形成術を施行した症例では，左室拡張末期容積は137.5±12.7 ml/m²から97.1±13.9 ml/m²，MAPを施行した症例では，MR grade は2.3±0.7から0.3±0.5へ改善した．完全血行再建と併施手術を積極的に行う我々の基本的治療方針は妥当な治療方針と思われる．

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