Cardiovascular OCT Imaging (eBook)

Ik-Kyung Jang, MD, PhD is Professor of Medicine at Harvard Medical School, Director of the Cardiology Laboratory for Integrative Physiology and Imaging (CLIPI) at Massachusetts General Hospital. Dr. Jang came to Massachusetts General Hospital in 1987 from Leuven University in Belgium, where he has completed his residency in medicine and fellowship in cardiology. He also successfully defended his doctorate thesis at the same university under the supervision of Professor Desire Collen. After his advanced fellowship in cardiology at MGH, he joined the staff and is currently working as a Physician and an interventional cardiologist in the Cardiology Division. His research interest has been acute coronary syndromes including acute myocardial infarction. His earlier research focused on pharmacology and physiology of thrombosis and thrombolysis including thrombin hypothesis and platelet inhibition. For the last fifteen years he has pioneered the application of intravascular Optical Coherence Tomography (OCT) to patients to better characterize coronary plaques and to understand the mechanisms of plaque rupture. In 2010 Dr. Jang established an international OCT Registry, which has more than 2000 patients from 20 sites across 6 countries.

Foreword 6
Contents 8
Contributors 10
1: The Development of OCT 13
1.1 Introduction 13
1.2 OCT and Ultrasound 15
1.3 Measuring Optical Echoes 16
1.3.1 Photographing Light in Flight 16
1.3.2 Femtosecond Time Domain Measurement 16
1.3.3 Low Coherence Interferometry 16
1.4 The Development of OCT 19
1.4.1 Early OCT Technology and Systems 19
1.4.2 Ophthalmic OCT Imaging 19
1.4.3 Beyond Ophthalmology to Intravascular and Endoscopic Imaging 21
1.4.4 Technology for Catheter and Endoscopic OCT Imaging 22
1.5 Early Intravascular OCT Imaging 23
1.5.1 Preclinical Feasibility Studies 23
1.5.2 Histological Validation Studies 24
1.5.3 Clinical Studies 24
1.6 Advances in Imaging Speed 25
1.6.1 Swept Source/Fourier Domain OCT 26
1.6.2 Light Sources for High Speed OCT 27
1.7 Technology Translation and Commercial Development 28
Conclusion 30
References 30
2: Physics of Cardiovascular OCT 34
2.1 Introduction 34
2.2 Principle of Operation of OCT 35
2.2.1 Frequency Domain Signal 35
2.2.2 Imaging Lateral Structure 36
2.3 Instrumentation 37
2.3.1 Interferometer 37
2.3.2 Light Source 39
2.3.3 Catheter 39
2.3.4 Rotary Junction 40
2.4 Light Tissue Interaction 41
2.4.1 Light Propagation in Biological Tissue 41
2.4.2 Tissue Optical Properties 42
2.5 Imaging with Intravascular OCT 44
2.5.1 Tomographic Reconstruction 44
2.5.2 Sampling 45
2.5.3 Signal to Noise Ratio and Sensitivity in OCT 46
2.5.4 Speckle 47
Conclusions 48
References 48
3: Histology Validation of OCT Images 50
3.1 Introduction 50
3.2 Normal Vessel Wall Morphology and Intimal Thickening 51
3.3 Atherosclerotic Plaque 51
3.4 Calcification 52
3.5 Fibroatheroma 52
3.6 Vulnerable Plaque 53
3.7 Thrombus 55
3.8 Neointima 59
3.9 Summary 61
References 61
4: Basic Interpretation Skills 63
4.1 Introduction 63
4.2 Systematic Approach to Image Acquisition and Interpretation 65
4.3 OCT Characteristics of Coronary Artery Disease 69
4.4 Acute Coronary Syndrome 72
4.5 Assessment of Coronary Stents After Implantation and at Follow-Up 74
4.6 Limitations 75
References 75
5: Intravascular OCT Imaging Artifacts 77
5.1 Introduction 77
5.2 Light Propagation in the Catheter, Lumen or Vessel Wall 77
5.2.1 Guide Wire Shadow 77
5.2.2 Ghost Lines 78
5.2.3 Residual Blood from Incomplete Lumen Flushing 78
5.2.3.1 Thrombus 79
5.2.4 Gas Bubbles 79
5.2.5 Metallic and Biodegradeable Stents 79
5.2.6 Superficial Shadowing by Macrophages 80
5.2.7 Saturation Artifact 80
5.3 Catheter Location and Movement 81
5.3.1 Non-Uniform Rotational Distortion (NURD) 81
5.3.2 Fold-Over Artifact 81
5.3.3 Tangential Light Drop-out 82
5.3.4 Sew-up or Seam Artifact 82
5.3.5 Effect of Beam Focus and Catheter Pupil on OCT Signal Strength 82
5.3.6 Obliquity/Eccentricity 84
5.4 Stent Artifacts 84
5.4.1 Merry-Go-Round Artifact 84
5.4.2 Blooming 85
5.4.3 3D Merry-Go-Round (“Ghost Struts”) 86
5.4.4 Sunflower Artifact 86
5.4.5 Bioabsorbable Stents 88
Conclusion 88
References 88
6: Clinical Presentations and Coronary Plaque Characteristics 90
6.1 In Vivo Characterization of Coronary Atherosclerosis by OCT 91
6.2 Clinical Presentations and OCT Coronary Plaque Characteristics 92
6.3 OCT Coronary Plaque Characteristics and Cardiovascular Risk Factors 98
6.3.1 Diabetes Mellitus 98
6.3.2 Hyperlipidemia 100
6.3.3 Smoking 102
6.3.4 Hypertension 102
6.3.5 Metabolic Syndrome (MetS) 103
6.3.6 Chronic Kidney Disease (CKD) 103
References 104
7: Insight into Pathogenesis of Acute Coronary Syndrome 107
7.1 Pathology of Underlying Mechanism of Acute Coronary Syndrome 107
7.2 Classification of Underlying Culprit Lesions in ACS 108
7.2.1 Evolution of the Paradigm for Atherosclerotic Lesions 108
7.2.2 In vivo Classification of Atherosclerotic Plaque Responsible for ACS 109
7.3 Plaque Rupture 110
7.3.1 Definition 110
7.3.2 Incidence 111
7.3.3 Plaque Ruptures in STEMI and Non–ST-segment Elevation Acute Coronary Syndrome 114
7.3.4 Plaque Rupture and Exertion 114
7.4 Plaque Erosion 114
7.4.1 Definition 114
7.4.2 Incidence 115
7.4.3 Plaque Erosion and Underlying Plaque Morphology 116
7.5 Calcified Nodule 120
7.5.1 Definition 120
7.5.2 Incidence and Underlying Plaque Characteristics 120
7.6 Concept of Vulnerable Plaque 121
Conclusions 123
References 123
8: Spontaneous Coronary Artery Dissection 126
8.1 Introduction 126
8.2 Pathogenesis 126
8.3 Clinical Characteristics 127
8.4 Coronary Angiography 128
8.5 Intravascular Ultrasound 128
8.6 Optical Coherence Tomography 129
8.6.1 Diagnosis and Examination of SCAD 129
8.6.1.1 Typical OCT SCAD Characteristics 129
8.6.1.2 Unique OCT Insights 131
8.6.2 Treatment Guidance in SCAD 132
8.7 OCT in SCAD 134
8.7.1 When to Avoid: Practical Consideration 134
8.7.2 Future Potential 134
Conclusion 135
References 135
9: Early Stent Evaluation 136
9.1 Introduction 136
9.2 Quantitative and Qualitative Stent Measurements 136
9.3 OCT Findings During PCI 137
9.3.1 Thrombus 137
9.3.2 Tissue Protrusion 137
9.3.3 Dissection 138
9.4 OCT Versus Intravascular Ultrasound for Stent Assessment 138
9.5 Strut Coverage 139
9.6 In Vivo OCT Data for Stent Coverage 139
9.7 Malapposition 140
9.8 OCT Characteristics of Neointima 140
9.9 In-stent Neoatherosclerosis 141
Conclusion 142
References 142
10: Late Stent Change 144
10.1 Stent Strut Coverage 145
10.2 Malapposition 148
10.3 Neointimal Characteristics 150
Conclusion 150
References 151
11: Stent Thrombosis 154
11.1 Introduction 154
11.2 Definition and Incidence 154
11.3 Clinical Outcomes 155
11.4 Associated Factors 155
11.5 The Pathology View 155
11.6 The Role of Intravascular Imaging to Assess Stent Thrombosis 156
11.7 OCT in Stent Thrombosis: Not All Stent Thrombosis Are Created Equal 156
11.8 How to Perform OCT in the Acute Setting of Stent Thrombosis 157
11.9 Information Provided by OCT 157
11.9.1 Thrombus Assessment 157
11.9.2 Inadequate Stent Implantation 157
11.9.3 Incomplete Stent Apposition 158
11.9.4 Uncovered Struts 164
11.9.5 Neoatherosclerosis 166
11.9.6 Other Mechanisms Involved in Stent Thrombosis 166
11.10 Limitations of OCT Imaging During Stent Thrombosis 169
11.11 New Perspectives for in Stent Thrombosis 170
Conclusions 170
References 170
12: Neoatherosclerosis 173
12.1 Introduction 173
12.2 Neointima Formation After Coronary Stent Implantation 173
12.3 Pathohistological Background of Neoatherosclerosis 174
12.4 IVUS and Angioscopic Findings of Neoatherosclerosis 176
12.5 OCT Findings of Neoatherosclerosis 176
12.5.1 BMS 176
12.5.2 DES 178
12.5.3 BMS vs DES 178
12.5.4 OCT-Derived Insight into the Pathogenesis of Neoatherosclerosis 179
12.5.5 Risk Factors for Neoatherosclerosis 180
12.5.6 Neoatherosclerosis in Second-­Generation DES 180
12.6 Clinical Significance of Neoatherosclerosis 180
Conclusions 182
References 182
13: Bioabsorbable Stent 184
13.1 Introduction and Rationale for the Use of Bioresorbable Scaffolds 184
13.2 Challenges for the Evaluation of Bioresorbable Scaffolds 185
13.3 Intracoronary OCT Imaging of Bioresorbable Scaffolds 186
13.3.1 OCT Can Reliably Guide Treatment Strategy 186
13.3.2 OCT Can Precisely Assess Scaffold Expansion and Strut Apposition 186
13.3.3 OCT Can Reliably Assess Scaffold Strut Distribution 187
13.3.4 OCT Can Accurately Assess Scaffold Strut Coverage 187
13.3.5 OCT Allows for Detailed Assessment of Scaffold Strut Degradation 188
13.3.6 Advantage of Three-Dimensional OCT 188
13.4 Clinical Experience 189
13.4.1 Polymeric Bioresorbable Scaffolds 189
13.4.1.1 Igaki-Tamai 189
13.4.1.2 Absorb BVS 189
13.4.1.3 DESolve 192
13.4.1.4 REVA 192
13.4.1.5 ART 193
13.4.1.6 IDEAL 193
13.4.1.7 Xinsorb 193
13.4.1.8 ON-ABS 194
13.4.1.9 FORTITUDE 194
13.4.2 Metallic Bioresorbable Scaffolds 194
13.4.2.1 AMS 194
13.5 Other Bioresorbable Scaffolds Currently Under Investigation 194
13.6 OCT Imaging of Bioresorbable Scaffolds – A Step Towards Routine Clinical Practice 194
References 195
14: Consensus Documents 199
14.1 Current Available OCT Technologies 199
14.2 Impact of Plaque Composition on Coronary Intervention 200
14.2.1 Calcification and Lipid Pool 200
14.2.2 Assessment of Ambiguous Angiographic Lesions and Deferral of Interventions 200
14.2.3 Identification of Vulnerable Plaques 200
14.3 OCT-Guided PCI Guidance 201
14.3.1 Frequency of OCT Findings of Sub-­Optimal Stenting and Clinical Role of OCT Guidance 201
14.4 Fields of Controversy for OCT Definitions 202
Conclusions 203
References 203
15: Future Development 206
15.1 Introduction 206
15.2 Intravascular Imaging in the Era of Evidence-Based Medicine 206
15.3 Research Areas 207
15.3.1 OCT Image Acquisition Within a Single Cardiac Cycle 207
15.3.2 3D Segmentation and Visualization 208
15.3.3 Angiographic Co-Registration 211
15.3.4 Functional Lesion Assessment 211
15.3.5 Multimodal Imaging 213
15.3.5.1 OCT-IVUS 213
15.3.5.2 OCT-Pressure 214
15.3.5.3 OCT-Spectroscopy 214
15.3.5.4 OCT-Fluorescence (Molecular Tagging) 215
15.3.6 Novel Blood Clearing Methods 217
References 217
Index 220