Assessment of Coronary Plaque Rupture and Erosion Added Value of Invasive Coronary Imaging for Plaque Rupture and Erosion Yukio Ozaki, MD, PhD, FACC, FESC Cardiology Dept., Fujita Health Univ. Toyoake, Japan
Declaration of Conflict of Interest Nothing to Disclose
ACS and Stable Angina ACS Stable Angina Feyter PJ, Ozaki Y, et al. Circulation 1995;92:1408-13
Stable and Unstable Plaque (ACS) - The stable plaque does not kill patients (i.e. just makes their lives difficult). - The unstable plaque cause thrombosis and partial or total vessel occlusion leading to major clinical events. Patrick W. Serruys; Gruentzig Lecture, ESC 2001
Vulnerable Lesion Characteristics Assessed by QCA, IVUS, Angioscopy ACS (n=44) SAP (n=23) p Thrombus, n (%) 30 (68%) 4 (17%) <.001 Occlusive 2 (5%) 0 (0%) Protruding 8 (18%) 1 (4%) Mural 20 (45%) 3 (13%) Lesion Surface, n (%) Ulcerated or Rough 31 (70%) 9 (39%) <.05 Smooth 13 (30%) 14(61%) <.05 Feyter PJ, Ozaki Y, et al. Circulation 1995;92:1408-13
Invasive & Noninvasive Imaging Modalities ACS SAP
High-risk and Vulnerable Plaque 1. A plaque prone to rupture (60-75%) Thin Cap Fibrous Atheroma (TCFA) 2. A plaque prone to erosion (20-40%) 3. A plaque with a calcified nodule (2-7%) Vulnerable Plaque Rupture Erosion Thrombosis Santorini Island Schaar JA, et al. Terminology for high-risk and vulnerable coronary artery plaques. European heart journal, 2004, 25:1077-1082.
Vulnerable plaque 1. A plaque prone to rupture (60-75%) TCFA (thin-cap fibroatheroma): A lipid-rich, atheromatous core A thin fibrous cap, with macrophage and lymphocyte infiltration decreased smooth muscle cell content Expansive remodeling Schaar JA, et al. European Heart Journal 2004; 25:1077-1082.
Vulnerable plaque 2. A plaque prone to erosion (20-40%) Eroded plaque with thrombosis Thick fibrous cap Rich in proteoglycan and smooth muscle Schaar JA, et al. European Heart Journal 2004;25:1077-1082.
Vulnerable plaque 3. A plaque with a calcified nodule (2-7%) Schaar JA, et al. European Heart Journal 2004;25:1077-1082.
Ruptured Plaque (RFC-ACS) A1 A2 B C 1mm 1mm 1mm D E F1 F2 Ozaki Y, et al Eur Heart J 2011;32:2814-23
Ozaki Y, et al Eur Heart J 2011;32:2814-23 Plaque Erosion (IFC-ACS) A B C 1mm 1mm D E F
Ozaki Y, et al Eur Heart J 2011;32:2814-23 A Stable Plaque B C 1mm 1mm D E F
Coronary tissue characterization IB-IVUS Fibrosis Dense Fibrosis Form cell Fibrosis Fibrosis Extra-cellarer lipid Fibrosis VH-IVUS Vulnerable plaque Fibro-fatty Lipid pool + attenuation Necrotic core Calcification Dense calcification
ClearView TM VISIWAVE TM lipid pool fibrosis dense fibrosis calcification 44.88(%) 49.26(%) 5.07(%) 0.79(%) lipid pool fibrosis dense fibrosis calcification 47.47(%) 47.95(%) 4.06(%) 0.52(%) EEM Area: 15.95 (mm 2 ) EEM Area: 16.04 (mm 2 ) Lumen Area: 4.31 (mm 2 ) Lumen Area: 4.27 (mm 2 ) Plaque Area: 11.64 (mm 2 ) Plaque Area:11.77 (mm 2 ) Ohota M, Ozaki Y, et al Circ J 2012;76:1678-1686
Coronary tissue characterization Baseline Intravascular Ultrasound Characteristics (Follow up 30 ± 7 months) Vulnerable Stable Plaque (n = 10) Plaque (n = 143) p Vessel area, mm2 13.9 ± 2.0 14.2 ± 3.5 0.72 Lumen area, mm2 6.1 ± 1.2 6.7 ± 2.0 0.31 Plaque area, mm2 8.0 ± 2.0 7.5 ± 2.4 0.41 Plaque burden, % 60 ± 9 52 ± 9 0.014 % diameter stenosis, % 35 ± 7 31 ± 7 0.10 % area stenosis, % 57 ± 8 52 ± 9 0.09 Eccentricity rate 0.70 ± 0.10 0.55 ± 0.17 0.013 Remodeling index 1.30 ± 0.08 1.16 ± 0.16 0.006 % fibrous area, % 23 ± 6 47 ± 14 <0.0001 % lipid area, % 72 ± 10 50 ± 16 <0.0001 Sano K, Kawasaki M et al. J Am Coll Cardio 2006;47:734
VH-TCFA in ACS and Stable Angina VH-TCFA definition: 1) NC >10% without overlying fibrous tissue 2) PAV >40% Rodriguez-Granillo GA, et al. J Am Coll Cardiol 2005;46:2038-42.
Witnessed Coronary Plaque Rupture during Cardiac Catheterization Gonzalo N, et al. JACC imaging 2011;4:437-8
All 30 pts with STEMI Kubo T. et al. J Am Coll Cardiol 2007;50:933-9
Role of OCT in Assessing Plaque Rupture/ Erosion CT-angiographic characteristics of RFC-ACS include lowattenuation plaques and positive plaque remodelling, features associated with IFC-ACS have not been previously described. We sought to determine whether CT characteristics of IFC- ACS lesions differed from RFC-ACS using OCT to identify erosions. Multi-modality approach used to leverage advantages of different invasive imaging tools
Baseline Clinical and Angiographic Characteristics RFC-ACS IFC-ACS Stable Angina p-value Patients (n) 30 13 29 Age (years) Male (n, %) NSTEMI (n, %) UAP (n, %) Stable Angina (n, %) 64.8±10.4 28 (93) 16 (53) 14 (47) - 62.9±7.5 9 (69) 6 (46) 7 (54) - 66.1±9.3 28 (96) - - 29 (100) 0.591 0.017 - - - Diabetes (n, %) Hypertension (%) Hypercholesterolemia(%) Smokers (n, %) Non-smoker Ex-smoker Current smoker 11 (37) 14 (47) 14 (47) 11 (37) 12 (40) 8 (27) 3 (23) 7 (54) 6 (46) 1 (8) 3 (23) 9 (69) 12 (41) 17 (59) 15 (51) 10 (35) 13 (48) 6 (21) 0.519 0.653 0.910 0.139 0.404 0.006
Baseline Angiographic Characteristics RFC-ACS IFC-ACS Stable Angina p-value Culprit Lesions (n) RCA/LAD/LCX (n, %) 30 13/ 16/ 1 13 5/ 6/ 2 29 8/ 16/ 5-0.405 Lesion type (A/B1/B2/C, n) 1/ 12/ 16/ 1 1/ 5/ 7/ 0 3/ 15/ 10/ 1 0.751 QCA - RD pre (mm) QCA - MLD pre (mm) 2.69±0.75 0.96±0.30 2.47±0.42 1.07±0.28 2.81±0.69 1.02±0.33 0.341 0.477 Non-culprit lesions in non-culprit vessel by MDCT RFC-ACS IFC-ACS Stable Angina p-value Non-Culprit Lesions (n) Average lesion severity (%) NCP < 30 HU (n, %) Spotty calcification (n, %) Positive Remodeling (n, %) 21 42±19 9 (43) 7 (33) 11 (52) 9 34±14 2 (22) 2 (22) 1 (11) 15 47±182 2 (13) 2 (13) 2 (13) - 0.472 0.138 0.382 0.016
OCT RFC-ACS IFC-ACS Stable Angina p-value Lesion (n) 30 13 29 Fibrous cap thickness (μm) 46±12 134±58 289±141 0.001 Lipid angle > 2 quads (n, %) 28 (93) 6 (46) 7 (24) 0.001 TCFA (n, %) Thrombus (n, %) 28 (93) 30 (100) 3 (23) 13 (100) 2 (7) 4 (14) 0.001 0.001 Thrombus Mural thrombus Protruding thrombus Yellow plaque White plaque Angioscopy RFC-ACS IFC-ACS Stable Angina p-value 26 (87) 15 (50) 11 (37) 25 (83) 5 (17) 13 (100) 10 (77) 3 (23) 9 (69) 4 (31) 4 (14) 3 (10) 1 (8) 17 (59) 12 (41) 0.001 - - 0.112 -
IVUS RFC-ACS IFC-ACS Stable Angina p-value (ANOVA) Lesion (n) 30 13 29 IVUS(mm 2 ) Vessel area pre 15.1±3.3 11.8±2.5 12.3±5.0 0.012 Lumen area pre 2.1±0.6 2.5±0.8 2.1±1.0 0.268 Plaque area pre 13.0±3.2 9.3±2.4 10.2±4.8 0.004 Prox. ref. vessel area 14.3±2.8 12.9±2.6 13.9±5.2 0.540 Distal. ref. vessel area 12.0±2.9 11.4±2.4 12.5±6.1 0.767 Remodeling index 1.14±0.11 A1)* 0.97±0.08 B1)* 0.95±0.11 C1)* 0.001 p<0.05 in A1)* vs. B1)* and A1)* vs. C1)*
64-slice/ 320-slice MDCT RFC-ACS IFC-ACS Stable Angina p-value (ANOVA) Lesion (n) 64-slice MDCT (n,%) NCP < 30 HU (LAP) Spotty calcification Large calcification Remodelling index Positive remodelling LAP & PR 30 27 (90) 24 (80) 3 (10) 13 5 (38) 3 (23) 1 (8) 29 4 (14) 7 (24) 18 (62) 1.11±0.07 A2)* 1.01±0.08 B2)* 1.01±0.07 C2)* 28 (93) 27 (90) 3 (23) 2 (9) 4 (14) 1 (3) - 0.001 0.001 0.001 0.001 0.001 0.001 p<0.05 in A2)* vs. B2)* and A2)* vs. C2)*
Future Directions - While approximately one-third of lesions responsible for major coronary thrombi on pathological analysis are secondary to plaque erosions, it is reasonable to presume that non-disrupted culprit lesions (IFC-ACS) in our study would represent plaque erosions. - We found no unique CT features of non-ruptured culprit lesions to enable their clear distinction from stable lesions - Identification and study of lesions at risk of erosion continues to rely on invasive intracoronary imaging
Imaging Modalities to Identify Morphological Features of Coronary Plaque Instability CT IVUS IVUS VH Palpograpy OCT Angioscopy 1 Fibrous cap thickness - - - - + - 2 Necrotic/lipid core ± ± + - + - 3 Lumen obstruction ± + + - - - 4 Outward remodeling + + + - - - 5 Inflammation - - - - - - 6 Calcification (spotty) + + + - + - 7 Yellow plaque - - - - - + 8 Strain - - - + - - 9 Low attenuation + - - - - - Feyter PJ, Nieman K. Editorial; Failure of CT coronary imaging to identify plaque erosion; a resetting of expectations. Eur Heart J 2011;32:2736-38
Conclusions Invasive intracoronary imaging has revolutionized our in vivo understanding of the pathogenesis of atherosclerotic plaque rupture and erosion The different modalities provide complementary information of different aspects of plaque risk and behaviour The non-invasive identification of lesions at risk of erosion remains challenging and a fertile area for future research