The Clinical Significance of Echo Signal Attenuation on Intravascular Ultrasound in Patients with Coronary Artery Disease Name : Shigeki Kimura, MD 1) Tsunekazu Kakuta, MD 2) Taishi Yonetsu, MD 2) Asami Suzuki, MD 2) Yoshito Iesaka, MD 2) Hideomi Fujiwara, MD 2) Mitsuaki Isobe, MD 1) 1)Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan 2)Division of Cardiology, Cardiovascular Center, Tsuchiura Kyodo Hospital, Ibaraki, Japan Presented in part at the Annual Scientific Sessions 2005, AHA, Dallas S Kimura, T Kakuta, et al. Circ Cardiovasc Intervent. 2009;2:

Presenter Disclosure Information Name : Shigeki Kimura, MD, Tsunekazu Kakuta, MD Taishi Yonetsu, MD, Asami Suzuki, MD Yoshito Iesaka, MD, Hideomi Fujiwara, MD Mitsuaki Isobe, MD Nothing to Disclose Related to This Presentation

Backgrounds1 Atherosclerotic plaque that shows echo signal attenuation (EA) without associated bright echoes is sometimes observed by intravascular ultrasound (IVUS), although its clinical significance remains unclear. Circ J. 2007;71: Okura et al. reported that atherosclerotic plaque with ultrasonic attenuation (EA) may be related to a transient deterioration in coronary flow during PCI in patients with acute coronary syndrome (ACS)

Backgrounds 2 A recent IVUS study reported that high level CRP, angiographic thrombus, deteriorated initial coronary flow, greater plaque burden, positive remodeling and plaque rupture were associated with attenuated plaque, and post-PCI no-reflow were frequent in ACS lesions with attenuated plaque. No attenuated plaque was observed in lesions with stable angina pectoris. JACC Cardiovasc Interv.2009;2:65-72 Several histopathological studies suggested that the presence of microcalcification and lipid rich plaque components might be associated with echo attenuation. Acute Cardiac Care. 2006; J Cardiol (4)

Aims To investigate the impact of EA on coronary perfusion and clinical outcome after PCI in patients with coronary artery disease. Further, to evaluate the pathological features of plaque with EA obtained by DCA

Method 1 Six hundred and eighty seven lesions in 687 consecutive patients (535 men and 152 women) who underwent preintervention IVUS were investigated. Exclusion: *in-stent restenotic lesions *bypass graft lesions *multiple culprit lesions *heavily calcified lesions *lesions treated with Rotablator or distal protection devices

Method 2 Quantitative coronary angiography was performed with a CMS- MEDIS system (Medis Medical Imaging System, Leiden, The Netherlands) Coronary flow was assessed according to Thrombolysis in Myocardial infarction (TIMI) flow grade and corrected TIMI frame count (CTFC) Angiographic no reflow was defined as TIMI grade 0-2 Myocardial perfusion was assessed by the myocardial blush grade (MBG)

Method 3 IVUS : Commercially available IVUS system, 40-MHz Boston Scientific Corporation/SciMed Automatic pullback of 0.5mm/s Plaque morphologies were qualitatively and quantitatively analyzed by two experienced observer according to the American College of Cardiology Clinical Expert Consensus Document on IVUS The culprit lesion was defined as the site of the smallest lumen and the reference site was set at the most normal looking region within 10mm proximal to it J Am Coll Cardiol. 2001; 37:

Methods 4 Definition of echo signal attenuation on IVUS IVUS findings showing ultrasound signal attenuation without very high intensity echo reflectors that involved >90 degrees of the vessel circumference and involved of >1mm

Method 5 All lesions were divided into two groups. (Group A: lesions with EA, Group NA: lesions without EA) Between the two groups, the differences in patient characteristics and lesion morphologies were compared. By subgroup analysis, 60 DCA samples (30 with EA and 30 without EA) underwent pathological examination Coronary flow after PCI and clinical outcome were compared between the two groups (DCA lesions were excluded from the analysis of coronary flow)

Method 6 The relationship between no reflow (TIMI 0-2) after PCI, EA and other variables (clinical characteristics, coronary risk factors, lesion morphologies on IVUS, angiographic characteristics, interventional strategies, and medications) was evaluated by multivariate logistic regression analysis

Methods 7 DCA was performed with IVUS guidance Directional removal of the plaque with EA was intended DCA samples were immediately immersion-fixed in 10% buffered formalin and embedded in paraffin These segments were stained with hematoxilin-eosin, Von Kossa stain and immunostaing with an anit-CD 68 antibody (M814 DAKO) Pathological assessment

Methods 8 In each lesion, the percent areas of the following 4 tissues were measured and averaged: (1) fibrous tissue (few cells and dense collagen fibers) (2) lipid-rich atheromatous tissue (foam cells, cholesterol clefts, and acellular debris) (3) hypercellular tissue (a loose connective tissue matrix containing numerous stellate cells) (4) thrombus (fibrin deposits) Circulation.2000;102:2180–2184 Lipid rich atheromatous tissue Fibrous tissueHypercellular tissue Thrombus

Methods 9 In addition, the presence of the following components was semi-quantitatively graded (0; absent, 1:sparse, and 2 abundant) and the mean grade for each lesion was calculated: macrophages, cholesterol clefts, hemosiderin, microcalcification (small calcium flecks <50 µ in diameter), and dense calcification (larger calcified masses MacrophagesCholesterol cleft Hemosiderin Microcalcification Dense calcification

Age (yrs) 66±14 64±12 ns 66±11 65±10 ns Female gender 33 (22.5%) 38(20.1%) ns 19 (19.4%) 62 (24.5%) ns Current Smoker 67 (45.6%) 82 (43.4%) ns 31 (31.6%) 73 (28.9%) ns Diabetes mellitus 54 (36.7%) 56 (29.6%) ns 34 (34.7%) 115 (45.5%) ns Hyperlipidemia 67 (45.6%) 96 (50.8%) ns 54 (55.1%) 160 (63.2%) ns Hypertention 95 (64.6%) 124 (65.6%) ns 71 (72.5%) 179 (70.8%) ns Previous myocardial infarction 18 (12.2%) 24 (12.7%) ns 50 (51.0%) 108 (42.7%) ns Aspirin use 46 (31.3%) 73 (38.6%) ns 84 (85.7%) 231 (91.3%) ns Ticlopidine use 34 (23.1%) 48 (25.4%) ns 60 (61.2%) 167 (66.0%) ns Statins use 38 (25.9%) 44 (23.3%) ns 45 (45.9%) 141 (55.7%) ns Patient characteristics A (n=147)NA (n=189) P ACS: acute coronary syndrome, SAP: stable angina pectoris A : echo attenuation, NA: non-attenuation EA was detected in 245 lesions (35.7%) The frequency of EA was significantly higher in ACS than in SAP (43.8% in ACS vs. 27.9% in SAP, p<0.001) Results 1 A (n=98)NA (n=253) P ACS (336)SAP (351)

LAD/RCA/LCX/LMT 76/51/20/0 86/70/25/8 ns 19/46/26/7 102/87/53/11 p<0.05 B2/C* 106 (72.1%) 129 (68.3%) ns 50 (51.0%) 148 (58.5%) ns Pre-RD (mm) 3.0 ± ± 0.6 p< ± ± 0.6 p<0.05 Pre-MLD (mm) 0.9 ± ± 0.6 ns 1.4 ± ± 0.4 ns Lesion length (mm) 18.0 ± ± 5.9 ns 16.5 ± ± 5.7 ns LV EF<40% 20 (13.6%) 17 ( 9.0%) ns 7 ( 7.1%) 18 ( 7.1%) ns Pre-TIMI** (0~2) 92 (62.6%) 107 (56.6%) ns 4 ( 4.1%) 11 ( 4.3%)ns A (n=147)NA (n=189) P ACS: acute coronary syndrome, SAP: stable angina pectoris, A : echo attenuation, NA: non-attenuation LAD, left anterior descending artery; RCA, right coronary artery; LCX, left circumflex artery; LMT, left main trunk *Lesion complexity was assessed according to the modified classification of the ACC/AHA. **TIMI: Thrombolysis in Myocardial Infarction (TIMI) flow grade RD: reference diameter, MLD: minimal lumen diameter, EF: ejection fraction Results 2 A (n=98)NA (n=253) P ACS SAP Angiographic lesion characteristics

Reference EEM CSA 18.2 ± ± 4.9 p< ± ± 5.2 p<0.01 (mm2) Lesion EEM CSA 18.9 ± ± 5.2 p< ± ± 4.6 p<0.001 (mm2) Lesion lumen CSA 2.1 ± ± 0.8 ns 2.5 ± ± 1.0 ns (mm2) Lesion plaque area 16.7± ± 5.0 p< ± ± 4.1 p<0.001 (mm2) Lesion plaque burden* p< p<0.001 (%) (85.9 to 91.0) (80.4 to 89.4) (81.0 to 88.8) (77.0 to 85.6) Results 3 ACS: acute coronary syndrome, SAP: stable angina pectoris, A : echo attenuation, NA: non-attenuation EEM: external elastic membrane, CSA: cross sectional area *Plaque area divided by (EEM-CSA) x100, presented as medians with interquartile ranges. Quantitative Coronary Ultrasound A (n=147)NA (n=189)PA (n=98)NA (n=253)P ACS SAP

Positive remodeling 81 (55.1%) 44 (23.3%) p< (44.9%) 59 (23.3%) p<0.001 Eccentricity 125 (85.0%) 132 (69.8%) p< (87.8%) 188 (74.3%) p<0.01 Thrombus 78 (53.1%) 105 (55.6%) ns 8 ( 8.2%) 7 ( 2.8%) p<0.05 Lipid core 39 (26.5%) 37 (19.6%) ns 22 (22.4%) 26 ( 10.3%) p<0.01 Ruptured plaque 83 (56.5%) 110 (58.2%) ns 23 (23.5%) 41 (16.2%) ns Mild Calcification* 71 (48.3%) 37 (19.6%) p< (51.0%) 71 (28.1%) p<0.001 Results 4 ACS: acute coronary syndrome, SAP: stable angina pectoris A : echo attenuation, NA: non-attenuation *presence of Mild Calcification was defined as having calcification with less than 90 ゜ in IVUS Lesion Morphologies in IVUS A (n=147)NA (n=189)A (n=98)NA (n=253)P ACS SAP P

BaselineFinal ACS ANAA SAP P<0.001 NS P= TIMI flow grade during PCI Results 5 NS ANAA TMG 0 TMG 1 TMG 2 TMG % % 40 20

Results 6 Group A Group NA 60 ACSSAP % % NS NS P< P<0.001 Frequencies of inadequate coronary flow during PCI (CTFC>40) BaselineFinalBaselineFinal

MBG 0 MBG 1 MBG 2 MBG 3 BaselineFinal ACS ANA A SAP ANAA NSP<0.001 NS Myocardial blush grade during PCI P<0.001 Results % % 40 20

Results 8 Group A Group NA 60 Procedural MN*Procedural MI** % % P<0.001 P< P<0.01 Frequencies of Peri-Procedural Myocardial Damage UAPSAPUAPSAP 16.9 P<0.05 *Myocardial necrosis: elevation of creatine kinase after PCI above the 99 th percentile of the reference range **Myocaridal infarction: elevation of creatine kinase after PCI by more than 3 times the uppser limit of the reference range

Fatal arrhythmia 3 ( 2.5) 0 ( 0.0) ns 0 ( 0.0) 0 ( 0.0) ns CHF* 9 ( 7.6) 3 ( 1.9) p< (4.8) 3 (1.3) ns Disabling stroke 1 (0.8) 0 ( 0.0) ns 0 (0.0) 0 (0.0) ns Reinfarction 1 (0.8) 0 (0.0) ns 0 (0.0) 1 (0.4) ns Ischemic TVR** 9 (7.6) 7 (4.4) ns 1 (1.2) 7 (3.1) ns Cardiac surgery 0 (0.0) 1 (0.6) ns 1 (1.2) 0 (0.0) ns Cardiac death 0 (0.0) 0 (0.0) ns 0 (0.0) 0 (0.0) ns MACE † 9 (7.6) 7 (4.4) ns 1 (1.2) 7 (3.1) ns Total Cardiac Events‡ 20 (16.8) 10 (6.3) p< (6.0) 9 (3.9) ns Results 9 ACS: acute coronary syndrome, SAP: stable angina pectoris, A : echo attenuation, NA: non-attenuation *congestive heart failure, ** target vessel revascularization, †Cardiac death, ischemic TVR, or reinfarction. ‡MACE, cardiac surgery, fatal arrhythmia, congestive heart failure, or unstable angina Clinical outcome During 1 Year of Follow-up A (n=119)NA (n=159)A (n=84)NA (n=229)P ACS SAP P

Frequency of TIMI 0-2 after PCI (%) Variable Factor Present Factor Absent OR (95% CI) P Baseline TIMI 0 to (3.60 to 15.48) p<0.001 Echo signal attenuation (3.52 to 15.11) p<0.001 Acute coronary syndrome (2.34 to 11.23) p<0.001 Primary aspiration (2.40 to 8.62) p<0.001 Ruptured plaque (2.25 to 8.88) p<0.001 Thrombus (IVUS) (2.26 to 8.88) p< Large reference area* (1.92 to 8.64) p<0.001 Current smoker (1.48 to 5.20) p<0.001 Ejection fraction <40% (1.26 to 6.09) 0.02 Large plaque burden† (1.38 to 5.46) Positive remodeling (1.36 to 4.74) Lipid core (0.98 to 3.97) LAD (0.97 to 3.35) Long lesion** (0.93 to 3.33) 0.08 Previous MI (0.19 to 0.98) Statins (0.18 to 0.82) 0.02 Ticlopidine (0.11 to 0.51) p<0.001 Aspirin (0.11 to 0.41) p<0.001 *reference area: > median **Lesion length > median, ACS: acute coronary syndrome Results 10 Univariate analysis for worse coronary flow after PCI

Variable Coefficient Standard Error OR(95% CI) P Baseline TIMI (2.79~12.51) p<0.001 Echo signal attenuation (2.64~11.85) p<0.001 Large reference area* (1.40~ 6.76) *plaque area > median, OR: odds ratio, CI: confidence interval, TIMI: Thrombolysis in Myocardial Infarction(TIMI) flow grade Results 11 Multivariate analysis for worse coronary flow after PCI

Results 12 Mean Percentage Area of Each Plaque Component % P<0.001 P<0.01 Atheromatous tissue 55.7 Fibrous tissue Hypercellular tissue Thrombus ns P< Group A Group NA

Macrophages 1.2± ±0.7 p<0.01 Cholesterol clefts 1.5± ±0.7 p<0.001 Hemosiderin 0.7± ±0.6 ns Microcalcification 1.4± ±1.0 p<0.01 Dense calcification 0.7± ±0.9 ns Results 13 Comparison of the mean grade of each plaque component With EAWithout EAP

Representative case (Female, 62 y.o) Target lesion was detected in left circumflex artery. DCA was performed. Stent was implanted. Echo signal attenuation was detected. Pre DCA Post DCA

Lipid rich plaque Microcalcium deposit, cholesterol clefts and acellular debris were observed. Pathological findings H-E Presented at the Annual Scientific Sessions 2005 of the American Heart Association, Dallas

The plaque was strongly stained by CD 68, CD36, Berlin Blue, CRP-8, respectively CD 68 CD 36 Berlin Blue CRP-8 Presented at the Annual Scientific Sessions 2005 of the American Heart Association, Dallas

In Summary EA was significantly more frequent in the culprit lesions of ACS than in those of SAP Coronary flow and myocardial perfusion after PCI were worse and the frequency of myocardial damage was higher in patients with either ACS or SAP whose culprit lesion showed EA on IVUS Multivariate analysis revealed a significant association between no reflow after PCI and EA along with a baseline TIMI grade 0-2 and a large reference area by IVUS EA was predominantly found in lesions from vessels with a large reference diameter and significant plaque burden. Lesions with EA showed a high frequency of positive remodeling, eccentricity, and mid calcification<90 degrees Histopathological examination of specimens obtained by DCA revealed a significantly higher prevalence of lipid-rich plaque, macrophage infiltration, cholesterol clefts, thrombus, and microcalcification in lesions with EA than in those without * * * * * S Kimura, T Kakuta, et al. Circ Cardiovasc Intervent. 2009;2:

Conclusion EA was detected in 35.7% of the culprit plaques, and was more common in patients with ACS than with SAP. Detection of EA in culprit lesions was a strong independent predictor of no reflow after PCI. EA might indicate that a lesion contains high-risk plaque components that are susceptible to distal embolization. S Kimura, T Kakuta, et al. Circ Cardiovasc Intervent. 2009;2: