Diagnosis and Management of Spontaneously Recanalized Coronary Thrombus Guided by Optical Coherence Tomography - Lessons From the French "Lotus Root" Registry

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Optical Coherence Tomography-OCT for Characterization of Non-Atherosclerotic Coronary Lesions in Acute Coronary Syndromes

Cardiovascular diseases are the main cause of death worldwide, with coronary artery disease being the predominant underlying etiology. The most prevalent coronary lesions are represented by the atherosclerotic plaques, in more than 85% of cases, but there are several other non-atherosclerotic lesions such as spontaneous coronary artery dissection and/or hematoma and spontaneous recanalization of coronary thrombus, which are less common, approximately 5% of cases, but with similar clinical manifestations as well as complications. There are insufficient data regarding the pathological mechanism, true prevalence and optimal treatment of these kind of coronary lesions. Optical coherence tomography (OCT) is an intracoronary imaging technique, developed in order to overcome the diagnostic limitations of a standard coronary angiography and has an extremely high resolution, similar to that of a usual histological evaluation of a biopsy sample, thus, OCT provides a histological-like information, but in a in vivo environment. The aim of this article is to review the current knowledge regarding non-atherosclerotic coronary lesions, with an emphasis on the importance of OCT for optimal identification, characterization of pathogenic mechanisms and optimal treatment selection.

Optical coherence tomography characterization of spontaneous recanalized coronary thrombus - Single center experience

Introduction: Recanalized thrombus is an under diagnosed clinical entity. Aim was to investigate the utility of optical coherence tomography (OCT) in identifying spontaneously recanalized thrombi (SRCT) for management in clinical practice. Methods: This was a retrospective study analyzing 2678 coronary angiograms over a 4-year period which included intravascular imaging guidance in 75.8% of the percutaneous coronary interventions (PCI). Angiographic suspicion of SRCT has hazy appearance seen in 34 patients. Results: Eight patients (7 males and 1 female) were confirmed with SRCT on OCT and two underwent intravascular ultrasound (IVUS). Median age was 52 years (range 33-67 years). Based on clinical symptoms, diagnosis was STEMI-2, NSTEMI-1, unstable angina-3 and chronic stable angina-2. Angiographic patterns were veiled/hazy appearances in 3; braided in 2; pseudo dissection in 2; and near occlusion in 1 patient. OCT findings displayed multiple small cavities, signal-rich with high backscattering and thin septa with smooth inner borders dividing the lumen and intercommunications. Presence of multiple holes conferred typical "Swiss cheese" or 'lotus root' like appearance, characteristic of recanalized thrombi. SRCT lesion length was (median interquartile ranges [IQR], 16.5[12.07-21.5] mm) and minimal luminal area (median [IQR], 1.77 [0.93-3.26] mm²) with significant stenosis (median [IQR], 74.0[67.0-81.0] %). Minimum/maximum number of channels were (median [IQR], 2.0[2.0-2.0]) and (median [IQR], 4.50[4.0-6.75]) respectively. Lipid rich plaque was predominant. IVUS demonstrated echo-lucent channels with small cavities. All but one patient underwent PCI. Conclusion: Intravascular imaging by OCT delineates the characteristics of recanalized thrombi and distinguishes ambiguous lesions. Majority of the lesions involving SRCT were significant both symptomatic and stenosis severity wise on OCT requiring PCI.

Role of Intravascular Imaging for the Diagnosis of Recanalized Coronary Thrombus

INTRODUCTION

Recanalized thrombus (RCT) of coronary arteries is frequently unrecognized in interventional cardiology practice. Intravascular imaging conclusively establishes its diagnosis, which otherwise is often misdiagnosed as fresh thrombus, spontaneous coronary artery dissection, or severe calcification based on angiography, alone. We hereby report our experience of 10 RCT patients, who had the intravascular imaging-guided diagnosis, followed by the successful percutaneous coronary intervention (PCI).

METHODS

It was a retrospective analysis of 10 patients, who had angiographic haziness of the target lesion during PCI, which were found to be RCT on intravascular imaging. Either optical coherence tomography (OCT) or intravascular ultrasound (IVUS) was performed to characterize RCT in 9 and 1 patient, respectively.

RESULTS

The mean age was 53 ± 13.1 years, comprising 9 men and 1 woman. Six patients had acute coronary syndrome, while four had chronic stable angina. Coronary angiography revealed ≥ 70% angiographic stenosis, with intracoronary haziness/filling defects which were linear, spiral or braided in appearance. OCT findings in 9 patients include signal-rich, high backscattered septa dividing the lumen into multiple small cavities communicating with each other, giving a "Swiss cheese" or "honeycomb" appearance. Intravascular ultrasound (IVUS) findings in one patient showed multiple cavities filled with blood speckling consistent with recanalized thrombus. All patients underwent successful PCI with image-guided optimization.

CONCLUSION

With the increasing use of intravascular imaging during PCI, RCT is frequently identified. OCT remains the investigation of choice to differentiate it from other similar entities on angiography.

Spontaneously Recanalised Coronary Thrombus in the Left Anterior Descending Artery Presenting as Ventricular Tachycardia

Spontaneously recanalized coronary thrombus (SRCT), also known as honeycomb, lotus root or Swiss-cheese lesion, is an increasingly recognised finding in patients undergoing coronary angiography. It is thought to arise from partial resorption of an initially occlusive thrombus. Most patients present with angina or exertional breathlessness. We describe a case of a 69-year-old patient who presented with ventricular tachycardia and was found to have SRCT in the left anterior descending artery on coronary angiography. Echocardiography and left ventricular (LV) angiography showed an akinetic, aneurysmal, thin-walled LV apex, diagnostic of an old anterior infarct. We highlight the role of optical coherence tomography in making the diagnosis and discuss the available management options of this condition.

Honeycomb-like structure in spontaneous recanalized coronary thrombus demonstrated by serial angiograms: a case report

Background

The honeycomb-like structure (HLS) is a rare cause of myocardial ischaemia characterized by multiple communicating channels divided by thin septa. The aetiology of this specific structure remains speculative.

Case summary

A 55-year-old man was admitted due to worsening effort angina during the previous 2 months. Diagnostic coronary angiography revealed occlusion of the distal right coronary artery (RCA) with good collateral flow from the left coronary artery. We considered this lesion as a recent total occlusion, and planned a percutaneous coronary intervention (PCI). At the time of PCI, 7 days after admission, an angiogram showed a spontaneous recanalization of the occlusive RCA. Intravascular ultrasound (IVUS) depicted a HLS at the recanalized lesion, including atherosclerotic stenosis. We managed these lesions with drug-eluting stents.

Discussion

A recanalized thrombus may manifest as a HLS. In this case, the patient suffered from worsening effort angina during the previous 2 months, we confirmed a spontaneous recanalization of the occluded coronary lesion by serial angiographic images, and observed HLS adjacent to the atherosclerotic attenuated plaque by using high-resolution IVUS. Recanalized organizing thrombus is considered an entity of HLS. However, all previous studies on the HLS in vivo have detected the structure in an already recanalized state. Therefore, the aetiology remained speculative and evidence has been indirect. This present case demonstrates that recanalized atherosclerotic thrombosis might be one of the causes of HLS.

Optical Coherence Tomography for In Vivo Identification, Characterization and Optimal Treatment of Spontaneous Recanalization of Coronary Thrombus

BACKGROUND/AIM

Spontaneous recanalization of coronary thrombus (SRCT) is a rare in vivo appearance, with a nonspecific angiographic aspect. The aim of this study was to investigate the importance of optical coherence tomography (OCT) use for SRCT identification, characterization of pathogenic mechanisms and optimal treatment.

PATIENTS AND METHODS

We retrospectively analyzed all patients with angiographic suspicion of SRCT who underwent coronary angiography for suspected coronary artery disease and afterward investigated by OCT imaging.

RESULTS

We identified 28 cases with angiographic suspicion of SCRT (0.41% of CA) and confirmed it in 4 patients (0.05% of CA). OCT provided insight about the underlying SRCT mechanism: possible complicated atherosclerotic plaques in two cases and, respectively, spontaneous coronary artery dissection in other two cases. OCT provided accurate lesion assessment and offered optimal PCI materials selection.

CONCLUSION

Besides providing the diagnosis, OCT also improved characterization of SRCT pathogenic mechanisms, in the four confirmed SRCT cases, supporting the role of coronary wall in situ complications, namely dissection of an atherosclerotic plaque or spontaneous dissection of a normal coronary wall.

Serial OCT Imaging of Multiple Woven-Appearing Lesions in a Single Patient Demonstrating Long-Term Clinical Stability

We report the case of a 58-year-old man with a history of myocardial infarction presenting with chest pain. Serial coronary artery optical coherence tomography over a 3-year period showed multiple woven-appearing lesions without progression, indicating that this type of lesion is potentially stable. (Level of Difficulty: Advanced.)