Circ J 2008; 72: 399–403 Multiple Yellow Plaques Assessed by Angioscopy With Quantitative Colorimetry in Patients With Myocardial Infarction Shigenobu Inami, MD*; Fumiyuki Ishibashi, MD*,**; Sergio Waxman, MD**; Kentaro Okamatsu, MD*; Koji Seimiya, MD*; Masamichi Takano, MD*; Ryota Uemura, MD*; Junko Sano, MD*; Kyoichi Mizuno, MD* Background Multiple angioscopic yellow plaques are associated with diffuse atherosclerotic plaque, and may be prevalent in patients with myocardial infarction (MI), so in the present study the yellow plaques in the coronary arteries of patients with MI was evaluated using quantitative colorimetry, and compared with those of patients with stable angina (SA). Methods and Results In the recorded angioscopic images of 3 coronary vessels in 29 patients (15 patients with MI, 14 with SA), yellow plaques were determined as visually yellow regions with b* value >0 (yellow color intensity) measured by the quantitative colorimetric method. A total of 90 yellow plaques were identified (b*=19.35±8.3, 3.05–45.35). Yellow plaques were significantly more prevalent in 14 (93%) of 15 culprit lesions of MI as compared with 8 (57%) of 14 of SA (p=0.03). In non-culprit segments, yellow plaques were similarly prevalent in 13 (87%) patients with MI and 11 (79%) with SA (p=0.65). Overall, multiple (≥2) yellow plaques were prevalent in 13 (87%) patients with MI, similar to the 10 (71%) with SA (p=0.38). The number of yellow plaques was significantly higher in patients with MI (3.8±1.9) than in those with SA (2.4±1.6, p=0.03). Conclusion The present study suggests that patients with MI tend to have diffuse atherosclerotic plaque in their coronary arteries. (Circ J 2008; 72: 399–403) Key Words: Arteriosclerosis; Coronary disease; Imaging; Plaque atients with myocardial infarction (MI) may have dif- spectively collected images and data from patients in Chiba fuse coronary plaque.1–4 Yellow plaque seen during Hokusoh Hospital, Nippon Medical School, Chiba, Japan. P coronary angioscopy is thought to be surrogates for Among 327 patients who underwent coronary angioscopy superficial intimal lipids.5–9 A recent study of ex-vivo coro- between 1998 and 2003, 29 non-consecutive patients (15 nary segments reported that yellow plaques, determined by MI, 14 SA) were selected for the present analysis based on angioscopy with quantitative colorimetry,10 were frequently the following criteria: (1) the culprit lesion was clearly iden- identified as several yellow spots on a single mass of dif- tified by angiography as the most significantly stenotic fuse atherosclerotic plaque, and that the number of yellow lesion in a coronary artery, which correlated with the pres- plaques correlated with the surface area or the burden of ence of ST segment changes on a 12-lead electrocardiogram atherosclerotic plaque.11 Therefore, multiple yellow plaques (ECG) or with a perfusion defect revealed by radionuclide may be prevalent in the coronary arteries of patients with scan; (2) angioscopic images of 3 coronary arteries were MI. Although a prior angioscopic study has reported this,12 available; (3) the patient had never previously undergone such findings have not been explored in other patient popu- either percutaneous coronary intervention or coronary artery lations. So, to determine whether multiple yellow plaques bypass grafting before the angioscopic procedure; (4) the are prevalent in other Japanese patients with MI, we used patient had never experienced prior coronary syndromes; angioscopy with quantitative colorimetry to examine pa- (5) the patient had not been undergoing continuous hemo- tients with MI, and compared the results with those from dialysis because of chronic renal failure; and (6) the patient patients who had stable angina (SA). had neither acute nor chronic inflammatory disease. Acute MI was defined by typical chest pain, ST segment elevation on the 12-lead ECG and serum creatine kinase elevation Methods greater than twice the upper limit of normal. Angioscopy The present study was a retrospective analysis of pro- was performed as previously described13,14 within 6 weeks from the onset of MI. SA was defined as a positive stress (Received May 7, 2007; revised manuscript received September 25, test and no change in the frequency, duration or intensity of 2007; accepted November 1, 2007) symptoms that had persisted for >4 weeks. Written informed *Chiba-Hokusoh Hospital, Nippon Medical School, Chiba, Japan, consent approved by the Institutional Review Board was **Lahey Clinic Medical Center, Burlington, MA, USA given by all patients. Mailing address: Fumiyuki Ishibashi, MD, Lahey Clinic Medical Cen- ter, 41 Mall Road, Burlington, MA, 01805, USA. E-mail: lotuslazor A laptop computer (Macintosh Powerbook G4, Apple [email protected] Computer, Inc, CA, USA) was connected to the S (Y/C) All rights are reserved to the Japanese Circulation Society. For per- signal output of a videotape player via an analog/digital missions, please e-mail: [email protected] converter (ADVC-100, Canopus Co, Kobe, Japan) with a Circulation Journal Vol.72, March 2008 400 INAMI S et al. Table 1 Patients’ Characteristics Myocardial infarction Stable angina p value (n=15) (n=14) Age, years 62.3±7.9 60.6±12.6 0.66 Males 13 11 0.65 Hypertension 10 9 0.89 Hyperlipidemia 11 11 >0.99 Diabetes mellitus 1 3 0.32 Cigarette smoking 9 8 0.87 Obesity 6 5 0.81 Family history 6 4 0.51 Culprit lesion, LAD/LCX/RCA 11/3/1 7/3/4 – Length of observed artery, mm LAD 61±11 63±9 0.58 LCX 41±15 37±9 0.25 RCA 68±29 63±16 0.64 Statin use (>4 weeks before procedure) 1 1 >0.99 Values are n and the mean±standard deviation. LAD, left anterior descending artery; LCX, left circumflex artery; RCA, right coronary artery. 6-pin IEEE 1394 connector. The display of the laptop the quantified color (b* value) in the respective angioscopic computer was adjusted to the color temperature=CIE D65 region. (based on the color temperature of xenon lamplight) and In the present analysis angioscopic yellow plaque was de- the gamma=2.2 (based on the definition in NTSC system) fined as a visually yellow region with a quantified b* value for the better visualization of image color. Customized soft- >0 (yellow color intensity). Because high yellow color in- ware (CSVEC-analyzer, ver.1.1.0d1) installed in the laptop tensity (HYCI, b* value ≥23) was associated with lipid computer was used for quantitative colorimetry, in which cores underneath thin fibrous caps in ex-vivo atherosclerotic the known L*a*b* color space was adopted to express the plaques of carotid/femoral arteries in our previous study,10 color (available at: http://en.wikipedia.org/wiki/Lab_color_ a HYCI region was also analyzed. space). Continuous variables are expressed as mean±standard All image analysis was performed on the laptop computer. deviation. Group differences or correlation were assessed Two observers reviewed the angioscopy movie images. In with the chi-square test or the Fisher exact probability test. culprit lesions, plaque color (yellow vs white) was visually Student’s t-test and the Mann-Whitney U test were used for determined as previously described.13,14 In non-culprit seg- continuous variables. The relationship between 2 continuous ments, yellow plaques were visually identified. For quantita- variables was assessed with Pearson’s correlation coefficient. tive colorimetry, a total of 97 angioscopic coronary regions A p-value of <0.05 was considered statistically significant. were determined in all culprit lesions, and yellow plaques in non-culprit segments, as follows: culprit of MI (n=15); non-culprit of MI (n=43); culprit of SA (n=14); and non- Results culprit of SA (n=25). All images showing angioscopic re- The clinical characteristics of the patients are shown in gions were saved as single-frame images (bitmap format) in Table1. A total of 90 yellow plaques were identified (b*= the laptop computer. 19.35±8.3, 3.05–45.35). Yellow plaques were significantly Two investigators performed the quantitative colorimetric more prevalent in 14 (93%) of 15 culprit lesions of MI as analysis separately and independently. On the saved image, compared with 8 (57%) of 14 of SA (p=0.03). In non-culprit a region of interest (ROI) for each coronary region was out- segments, yellow plaques were similarly prevalent in 13 lined in freehand with the computer cursor and demarcated (87%) patients with MI and 11 (79%) with SA (p=0.65, as follows: (1) a homogeneous white or yellow region with- Fig1). Overall, multiple (≥2) yellow plaques were preva- in the plaque; (2) a yellow region within a mixed yellow and lent in 13 (87%) patients with MI, which was similar to the white plaque; or (3) a clearly deeper yellow region within a 10 (71%) with SA (p=0.38, Fig2). The number of yellow heterogeneous yellow plaque. Overlying thrombus was ex- plaques in the coronary arteries was significantly higher in cluded. The mean value of brightness L* was measured to patients with MI (3.8±1.9) than in those with SA (2.4±1.6, confirm that it was within the established optimal range of p=0.03, Fig3). The number was significantly higher in the L* values.10 If brightness L* in the ROI was not optimal, a culprit artery of MI (1.9±1.2) than in the culprit artery of SA different single-frame image was chosen and the process (0.9±0.6, p=0.01); however, it was similar in non-culprit repeated until optimal brightness L* was confirmed in the arteries (1.8±1.1 vs 1.4±1.2, p=0.39, Fig4).