42A ABSTRACTS - Angiography & Interventional Cardiology JACC March 19,2003 between RCA and control group (p=O.lO). Conclusions: Coronary sinus blood temperature measurement is increased compared to that of right atrium in patients with significant lesions in LCA. This technique may prove useful in identifying patients with enhanced inflammatory involvement and additional studies are required for evaluating the clinical significance of coronary sinus thermogra- phy in risk stratification and prognosis. 1102-182 Comparison of Culprit Lesions Showing Negative Remodeling Between Acute Coronary Syndrome and Stable Angina Pectoris Shoichi Ehara, Yoshiki Kobayashi, Daijyu Fukuda, Yasuhiro Nakamura, Shinichi Shimodozono, Haiime Yamashita, Kenei Shimada, Minoru Yoshivama. Kazuhide Takeuchi, JunichiYoshikawa, Makiko &da, Osaka City University, Osaka, Japan Background: Previous intravascular ultrasound (IVUS) studies have shown that positive remodeling (PR) is associated with acute coronary syndromes (ACS), whereas negative remodeling (NR) is more common in stable angina pectoris (SAP). However, NR could be found in 30.50% of patients with ACS. The purpose of this study is to elucidate whether some differences are present at the culprit lesion showing NR in patients with ACS and SAP. Methods Preinterventional IVUS images of 136 patients (99 ACS. 37 SAP) were identified. Remodeling ratio (RR) was defined as the ratio of external elastic membrane area at the culprit lesion to at the proximal reference. NR was defined as RRc0.95. Results In ACS group, NR was observed in 39 patients (39%), while in SAP group NR was found in 23 patients (62%). In lesions showing NR, calcified plaques were more frequent in SAP (ACS: 15%, SAP: 50%), but in ACS no calcification plaques were more common (ACS: 51%. SAP: 25%) (p<O.O5). Moreover, patients showing NR in ACS were significantly younger than in SAP (p< 0.05). Conclusion : The differences in plaque morphology of NR between ACS and SAP may reflect different progression mechanisms of NR in ACS, eventually this may lead to acute coronary event. 1102-183 In-\livo Characterization of Plaque Morphology by Optical Coherence Tomography Predicts Coronary Artery Remodeling Briain D. Mac Neill, Harry C. Lowe, Eugene Pomeranstev, Denise DeJoseph, Hiroshi Yabushita, Guiflermo J. Tearney, Brett E. Bouma, Ik-Kyung Jang, Massachusetts General Hospital, Boston, MA, Wellman Laboratory of Photomedicine, Boston, MA Background: The pathophysiology of remodeling and its relationship to plaque morphol- ogy are poorly understood. Positive remodeling is associated with acute coronary syn- dromes, whereas negative remodeling more commonly presents as stable angina. Optical coherence tomography (OCT) is a high resolution imaging technique capable of in-viva plaque characterization. Hypothesis: Plaque morphology, characterized in -viva by OCT. predicts coronary remodeling. Methods: lntracoronary OCT imaging was performed with a 3.2 Fr OCT catheter. Intra- vascular ultrasound (IVUS) was performed with a 40Hz Atlantis” catheter. At each site, the external elastic membrane (EEM) area was measured using IVUS and the plaque was characterized using OCT. The remodeling ratio (RR) was calculated as the ratio of the EEM at the culprit lesion to the EEM at the proximal reference. Positive remodeling was defined as an RR > 1.05, negative remodeling as an RR< 0.95; and absence of remodeling as an RR between 0.95 and 1.05. Results: A total of 62 lesions were imaged in 50 patients. The results are shown in the table. Positive remodeling was more common in lipid rich plaque and negative remodel- ing in fibrous plaque. Mixed plaque was associated with both positive and negative remodeling. Conclusion: This is the first in-viva demonstration of the relationship between plaque morphology and arterial remodeling response. Lipid rich plaque resulted in positive remodeling, supporting the role of remodeling in plaque vulnerability. Lipid Rich Plaque MixedPlaque Fibrous Plaque p Value Number 27 15 40 Positive 16 9 0 0.002 Remodeling Negative 1 3 3 Remodeling No 10 3 37 Remodeling Remodeling Index 1.17 f 0.16 0.69 * 0.14 0.77 f 0.12 0.001 1102-184 Detection of Thin-Capped Fibroatheromas in Human Aorta Tissue With Near Infrared Spectroscopy Through Blood Barbara Marshik , Huwei Tan, Jing Tang, Anna Lindquist, Andres Zuluaga, InfraReDx. Incorporated, Cambridge, MA Background: A method is needed to identify thin-capped fibroatheroma likely to cause acute coronary events in humans. We tested the ability of near infrared (NIR) spectros- copy to characterize tissue through blood without vessel occlusion. Methods: NIR spectra of human aorlic tissue were acquired through whole blood at 36°C from 400 - 2500 nm using a l/2 inch fiber optic probe. Probe-to-specimen depths were varied simulating in viva parameters up to 1.5mm. Lipid rich aortic plaques were separated into three groups: disrupted. thin-capped, and thick-capped with average cap thicknesses of 231+791,237*102p, and 629*14Op respectively. Partial least squares - discriminant analysis was used to create models using disrupted plaques with classifica- tion as the prediction mode. Results The first model discriminated other plaque compositions from both thin-capped and thick-capped plaques (see Class Separation in Table) with excellent results. A sec- ond model was built that optimized the discrimination between the thin-capped and thick- capped plaques through variable depths. The model was also used to discriminate other tissue types with good results (see Cap Separation in Table). Better results are antici- pated with a smaller probe illumination area. Conclusion: NIR spectroscopy can identify thin-capped plaques through blood with high sensitivity and specificity supporting the development of a NIR catheter to identify thin- capped fibroatheromas through blood in tiw in coronary arteries. MODEL Thin- Thick- Fibrotic Calcific Normal Capped Capped (Specificity) (Specificity) (Specificit (Sensitivit n=20 n=35 n=33 Y) Y) n=41 n=16 Class Separation CaP Separation 93% 70% SENS 91% 65% 96% 66% 72%’ SPEC 89% 96% 99% ’ Disrupted versus Fibrotic plaques used in training set’ Disrupted versus Thick- capped lipid plaques used in training set. 1102-185 Circadian Variation of Plaque Rupture in Patients With Acute Myocardial Infarction Atsushi Tanaka, Takahiko Kawarabayashi, Toshihiko Sane, Hiroki Oe, Yoshiharu Nishibori, Masashi Namba, Yukio Nishida, Daiju Fukuda, Kenei Shimada, Junichi Yoshikawa, Baba Memorial Hospital, Sakai, Japan, Osaka City University, Osaka, Japan Background: Studies have reported a circadian variation in the onset of acute myocardial infarction (AMI). Pathological studies have revealed that plaque rupture is one of the major causes of AMI, but none of these has looked specifically at the circadian variation of plaque rupture. The aim of this study was to use intravascular ultrasound (IVUS) to investigate the circadian variation of plaque rupture in AMI. Methods: This study comprised 174 consecutive patients with AMI who underwent pre- intervention IVUS. All patients were assigned to either a rupture group or a non-rupture group according to the pre-intervention IVUS. Results: In the 61 (47%) patients in the rupture group, the frequency of the onset of AMI increases significantly in the period from 6 AM to 12 noon compared with all the other periods (respectively, p<O.O5). The clinical features of AMI in the rupture group were characterized as occurring significantly more at rest (67% vs. 31%, pcO.Ol), and after significantly less pre-infarction angina (22% vs. 57%, p<O.Ol) compared with the non- rupture group. A different circadian variation was identified in the non-rupture group, characterized as a significant nocturnal nadir (12:OO midnight to 6 AM, compared with all other periods, respectively, pcO.05). Conclusion: The circadian variation of AMI is the result of a morning increase in inci- dence of plaque rupture. Our results may be of benefit for understanding and preventing the onset of some classes of AMI. 1102-186 Intrinsic Fluorescence Accurately Identifies Coronary Plaques With Superficial Foam Cells and High Content of Proteoglycans and Smooth Muscle Cells Georqe 0. Anqheloiw Jonathan T. Arendt, Markus G. Mueller. Irene Georgakoudi, Abigail S. Haka, Jason T. Motz, Barry D. Kuban, Jonathan Myles, Eugene A. Podrez, Michael S. Feld, John R. Kramer, The Cleveland Clinic Foundation, Cleveland, OH, Massachusetts Institute of Technology, Cambridge, MA Background Plaques with abundant superficial proteoglycans (PG) and smooth muscle cells (SMC) are prone to erosion and thrombus development. Superficial foam cells (SFC) are another important cause of coronary plaque instability and thrombogenicity. We hypothesize that areas with SFC are rich in PG and SMC, and intrinsic fluorescence (IF) is an accurate method for their detection. Methods We subjected 35 normal, and 96 intimal thickening and atheromatous coronary segments harvested from heart transplant and autopsy cases to measurements of reflec- tance and multiple excitation wavelength &) laser induced fluorescence. We used hematoxylin and eosin slides to quantify the area occupied by SFC on a target surface represented by the superficial 200pm of each specimen, on a transversal length equal to the diameter of the optic probe used for spectroscopic measurements (1000 pm). Movat’s and anti a actin staining were performed in specimens with SFC. After process- ing the spectroscopic data, we extracted IF spectra, fit them to a linear combination of collagen, necrotic core lkpoproteins and SFC spectra at X,=460 nm, and then calculated the SFC and collagen contribution to IF at this wavelength. The SFC spectrum has been obtained through computational methods and validated against spectra of Cu and myeloperoxidase oxidized LDL. A diagnostic algorithm, employing leave-one-out cross- validation and logistic regression, was built using the ratio of SFC and collagen contribu- tions to IF at X,=460 nm as diagnostic parameter, to separate coronary segments with SFC from those without. ResultsSFC were histologically noted in 10 intimal thickening, 12 fibrous cap atheroma- tous and 2 thin fibrous cap atheromatous specimens. Large accumulations of PG in- between and under the SFC were noted in 9 intimal thickening and 12 fibrous cap ather- ornatous specimens. SMC were observed in the SFC area in 6 intimal thickening and 6 fibrous cap atheromatous specimens. The algorithm built as described diagnosed the Downloaded From: http://173.193.11.214/ on 02/21/2013