Diagnosis and Prognostic Value of the Underlying Cause of Acute Coronary Syndrome in Optical Coherence Tomography-Guided Emergency Percutaneous Coronary Intervention

Defining "Vulnerable" in coronary artery disease: predisposing factors and preventive measures

The likelihood of a plaque to cause an acute coronary syndrome (ACS) depends on several factors, both lesion- and patient-related. One of the most investigated and established contributing factors is the presence of high-risk or "vulnerable plaque" characteristics, which have been correlated with increased incidence of major adverse cardiovascular events (MACE). The recognition, however, that a significant percentage of vulnerable plaques do not result in causing clinical events has led the scientific community towards the more multifaceted concept of "vulnerable patients". Incorporating the morphological features of an atherosclerotic plaque into its hemodynamic surroundings can better predict the chance of its disruption, as altered fluid dynamics play a significant role in plaque destabilization. The advances in coronary imaging and the field of computational fluid dynamics (CFD) can contribute to develop more accurate lesion- and patient-related ACS prediction models that take into account both the morphology of a plaque and the forces applied upon it. The aim of this review is to provide the latest data regarding the aforementioned predictive factors as well as relevant preventive measures.

Impact of Calcified Nodules on Clinical Outcomes in Hemodialysis Patients Undergoing Percutaneous Coronary Intervention

Calcified nodules (CNs) are associated with poor prognosis after percutaneous coronary intervention (PCI) and have been reported to occur more frequently in hemodialysis patients. However, their prognosis in hemodialysis patients undergoing PCI has not been fully elucidated. We aimed to investigate the prognosis of hemodialysis patients who underwent PCI for CNs using intravascular ultrasound (IVUS) and/or optical coherence tomography (OCT)/optical frequency domain imaging (OFDI). About 141 hemodialysis patients who underwent PCI between January 2020 and December 2021 were analyzed retrospectively in a single center. CNs are defined as heavily calcified plaques that protruding into lumen in a convex shape. MACE (a composite of cardiovascular death, target lesion related myocardial infarction, and target lesion revascularization) between CNs and Non-CNs at 1 year were compared. In the entire study population, the mean age was 69.3 ± 10.7 years, and 94 (77.0%) were male. At 1 year, the incidence of MACE following PCI was significantly higher in the CNs group (39.2% vs 9.9%, log-rank p <0.001), particularly for cardiovascular death (17.7% vs 4.2%, log-rank p = 0.009). After multivariate analysis adjusting for demographic characteristics, CNs remained independently associated with increased risk of MACE (adjusted hazard ratio: 4.93, 95% confidence interval 2.07 to 11.76; p <0.001). CNs were associated with a higher incidence of MACE and a higher cardiovascular death rate in hemodialysis patients who underwent PCI.

Stent-Edge Hinge Movement in a Calcified Lesion Is Associated With Increased Prevalence of a Calcified Nodule at Follow-Up

BACKGROUND

Coronary stenting alters vessel dynamics, displacing hinge movement closer to stent edges. We aimed to investigate whether calcified nodules (CNs) are more frequent at stent edges associated with calcium.

METHODS

In vessels with previously implanted stents evaluated by optical coherence tomography, 4 different calcified lesions were studied: stent-edge calcified lesions with or without a CN, and unstented native calcified lesions with or without a CN.

RESULTS

In 801 patients, 989 stent-edge calcified lesions and 354 unstented native calcified lesions were identified. Stent-edge calcified lesions exhibited a higher prevalence of CNs versus native calcified lesions (15.7% versus 5.1%; P<0.001) and were observed in locations (mid left anterior descending artery, mid left circumflex, or branches) where no unstented native vessel CNs were seen. Stent-edge (versus native vessel) location (odds ratio [OR], 4.58 [95% CI, 2.23-9.43]) predicted the presence of a CN. Correspondingly, greater angiographic (systole-diastole) ∆angle at the stent edge or unstented lesion (per 10°, OR, 2.27 [95% CI, 1.43-3.60]) and greater calcium burden: calcium length (per 10 mm, OR, 4.04 [95% CI, 2.36-6.92]), maximum calcium arc (per 90°, OR, 1.65 [95% CI, 1.25-2.17]), and maximum calcium thickness (per 0.1 mm, OR, 1.25 [95% CI, 1.15-1.36]) were associated with the presence of a CN. Stent-edge CNs were associated with a higher rate of stent-edge calcified lesion-related major adverse cardiac events (a composite of cardiac death, target vessel-related myocardial infarction, clinically driven target lesion revascularization, or definite/probable stent thrombosis) compared with stent edges without a CN (15.9% versus 6.5%; P=0.01), mainly driven by target lesion revascularization.

CONCLUSIONS

Stent-edge calcium may predispose to the development of a CN. Stent-edge CNs were associated with a higher major adverse cardiac events rate than stent edges without a CN, whether treated or untreated.

Calcified nodules in the coronary arteries: systematic review on incidence and percutaneous coronary intervention outcomes

INTRODUCTION AND OBJECTIVES

Calcified nodules (CN) have been associated with higher complexity and worse outcomes after percutaneous coronary intervention (PCI) in both stable and unstable coronary disease. The aim of this systematic review was to summarize the current evidence on CN.

METHODS

Systematic review of published studies on the prevalence, clinical associations, and impact of CN on outcomes after PCI up to November 2024.

RESULTS

We identified 474 publications, of which 87 were included (all observational). CN were divided into 2 types: noneruptive CN (NECN), with an intact fibrous cap; and eruptive CN (ECN), with disruption of the fibrous cap with or without thrombus. The most common location was the right coronary artery (28%-71%). Angiography-based diagnostic sensitivity was low (18%-38%). Optical coherence tomography was preferred for type differentiation. The main clinical factors associated with CN were older age, diabetes mellitus, and chronic kidney disease. CN were considered the culprit lesion in 3% to 18% of acute coronary syndromes but were also present in up to 30% of nonculprit arteries. ECN were associated with more events at follow-up than NECN (20% vs 3.3% at 1 year). Post-PCI, CN were associated with lower minimum lumen area (MLA), higher rates of stent-edge dissection (44%-73%), malapposition (71%-96%), and underexpansion (60%-77%). ECN were associated with better acute results but worse long-term outcomes compared with NECN.

CONCLUSIONS

CN are often present in acute coronary syndrome culprit and stable coronary lesions. Intracoronary imaging is essential for the diagnosis and differentiation of CN. CN are associated with worse outcomes after PCI, acutely and during follow-up.

Recent advances and clinical implications of intravascular imaging

Coronary artery disease (CAD) remains a major contributor to the global mortality rate. Accurate and detailed evaluation of atherosclerotic plaque characteristics is essential for effective risk assessment and treatment planning. Although conventional coronary angiography excels at quantifying luminal stenosis, information on plaque composition and structure remains limited. Recent advances in intravascular imaging (IVI) have bridged this gap by enabling high-resolution visualization of the vessel wall and plaque morphology, thereby enhancing treatment strategies and facilitating comprehensive risk stratification. Among the principal IVI modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS) provide distinct benefits. IVUS accurately measures vessel diameter and plaque burden, offering critical guidance for managing complex lesions and left main artery disease. The extremely high spatial resolution of OCT allows precise identification of high-risk plaque features, such as thin fibrous caps. NIRS complements these techniques by quantitatively assessing lipid components within plaques, making it particularly useful in predicting future cardiovascular events. In this review, we summarize the latest evidence on applying IVI modalities to the evaluation and treatment of CAD. We focus on the assessment of plaque morphology, identification of high-risk lesions, and the role of IVI-guided percutaneous coronary intervention (PCI). The continued development of hybrid imaging systems and artificial intelligence-based image analysis may produce more precise and safer PCI approaches. Consequently, IVI is poised to become indispensable in managing CAD, paving the way for more personalized treatment strategies tailored to the specific lesion characteristics of each patient.

Natural history of a newly developed calcified nodule: incidence, predictors, and clinical outcomes

BACKGROUND

Calcified nodules (CNs) are an increasingly important, high-risk lesion subset.

AIMS

We sought to identify the emergence of new CNs and the relation between underlying plaque characteristics and new CN development.

METHODS

Patients who had undergone two optical coherence tomography (OCT) studies that imaged the same untreated calcified lesion at baseline and follow-up were included. New CNs were an accumulation of small calcium fragments at follow-up that were not present at baseline. Cardiac death, myocardial infarction (MI), or clinically driven revascularisation related to OCT-imaged, but untreated, calcified lesions were then evaluated.

RESULTS

Among 372 untreated calcified lesions, with a median of 1.5 (first and third quartiles: 0.7-2.9) years between baseline and follow-up OCTs, new CNs were observed in 7.0% (26/372) of lesions at follow-up. Attenuated calcium representing residual lipid (odds ratio [OR] 3.38, 95% confidence interval [CI]: 1.15-9.98; p=0.03); log10 calcium volume index (length×maximum arc×maximum thickness; OR 2.76, 95% CI: 1.10-6.95; p=0.03); angiographic Δangle between systole and diastole, per 10° (OR 2.30, 95% CI: 1.25-4.22; p=0.01); and time since baseline OCT, per year (OR 1.36, 95% CI: 1.05-1.75; p=0.02) were all associated with new CN development. Clinical events were revascularisation and/or MI and were more frequent in lesions with versus without a new CN (29.3% vs 15.3%; p=0.04).

CONCLUSIONS

New CNs developed in untreated, lipid-containing, severely calcified lesions with a larger angiographic hinge motion (between systole and diastole), compared with lesions without CNs, and were associated with worse clinical outcomes.

Predictors of Optical Coherence Tomography-Defined Calcified Nodules in Patients With Acute Coronary Syndrome - A Substudy From the TACTICS Registry

BACKGROUND

Recent studies suggest that the presence of calcified nodules (CN) is associated with worse prognosis in patients with acute coronary syndrome (ACS). We investigated clinical predictors of optical coherence tomography (OCT)-defined CN in ACS patients in a prospective multicenter registry.

METHODS AND RESULTS

We investigated 695 patients enrolled in the TACTICS registry who underwent OCT assessment of the culprit lesion during primary percutaneous coronary intervention. OCT-CN was defined as calcific nodules erupting into the lumen with disruption of the fibrous cap and an underlying calcified plate. Compared with patients without OCT-CN, patients with OCT-CN (n=28) were older (mean [±SD] age 75.0±11.3 vs. 65.7±12.7 years; P<0.001), had a higher prevalence of diabetes (50.0% vs. 29.4%; P=0.034), hemodialysis (21.4% vs. 1.6%; P<0.001), and Killip Class III/IV heart failure (21.4% vs. 5.7%; P=0.003), and a higher preprocedural SYNTAX score (median [interquartile range] score 15 [11-25] vs. 11 [7-19]; P=0.003). On multivariable analysis, age (odds ratio [OR] 1.072; P<0.001), hemodialysis (OR 16.571; P<0.001), and Killip Class III/IV (OR 4.466; P=0.004) were significantly associated with the presence of OCT-CN. In non-dialysis patients (n=678), age (OR 1.081; P<0.001), diabetes (OR 3.046; P=0.014), and Killip Class III/IV (OR 4.414; P=0.009) were significantly associated with the presence of OCT-CN.

CONCLUSIONS

The TACTICS registry shows that OCT-CN is associated with lesion severity and poor clinical background, which may worsen prognosis.

Optical Coherence Tomography in Myocardial Infarction Management: Enhancing Precision in Percutaneous Coronary Intervention

In acute myocardial infarction (AMI), the urgency of coronary revascularization through percutaneous coronary intervention (PCI) is paramount, offering notable advantages over pharmacologic treatment. However, the persistent risk of adverse events, including recurrent AMI and heart failure post-revascularization, underscores the necessity for enhanced strategies in managing coronary artery disease. Traditional angiography, while widely employed, presents significant limitations by providing only two-dimensional representations of complex three-dimensional vascular structures, hampering the accurate assessment of plaque characteristics and stenosis severity. Intravascular imaging, specifically optical coherence tomography (OCT), significantly addresses these limitations with superior spatial resolution compared to intravascular ultrasound (IVUS). Within the context of AMI, OCT serves dual purposes: as a diagnostic tool to accurately identify culprit lesions in ambiguous cases and as a guide for optimizing PCI procedures. Its capacity to differentiate between various mechanisms of acute coronary syndrome, such as plaque rupture and spontaneous coronary dissection, enhances its diagnostic potential. Furthermore, OCT facilitates precise lesion preparation, optimal stent sizing, and confirms stent deployment efficacy. Recent meta-analyses indicate that OCT-guided PCI markedly improves safety and efficacy in revascularization, subsequently decreasing the risks of mortality and complications. This review emphasizes the critical role of OCT in refining patient-specific therapeutic approaches, aligning with the principles of precision medicine to enhance clinical outcomes for individuals experiencing AMI.

OCT-based comparative evaluation of culprit lesion morphology in very young versus older adult patients with STEMI

Background

The clinical and pathophysiological characteristics of coronary artery disease in very young adults are poorly described.

Aims

Using optical coherence tomography (OCT), we compared culprit lesion morphology in very young adult patients (≤35 years) versus older adult patients (>60 years) with ST-segment elevation myocardial infarction (STEMI).

Methods

Culprit lesion morphology was classified as plaque rupture, plaque erosion, or calcified nodule. Thrombus age was subclassified into acute (intraluminal thrombus with surface irregularity) or subacute (mostly mural thrombus with a smooth surface).

Results

A total of 61 patients who underwent thrombolysis within 24 hours from symptom onset were included, with 38 (59.7%) subjects ≤35 years and 23 (40.3%) subjects >60 years of age. As an underlying mechanism of STEMI thrombosis, plaque erosion was more common in very young patients (52.6% vs 21.7%; p=0.02) while plaque rupture was more common in elderly patients (65.2% vs 36.8%; p=0.03). Acute or subacute thrombus was identified in 68.9% (42/61) of patients, with red thrombus being more frequent in very young patients. In the entire patient cohort, acute thrombus was more frequent in plaque rupture compared with plaque erosion (62.0% vs 28.0%; p=0.01), whereas subacute thrombus was more common in plaque erosion versus plaque rupture (52.0% vs 10.3%; p=0.0008).

Conclusions

OCT showed that plaque erosion and plaque rupture were the most common underlying STEMI mechanisms in very young patients and older patients, respectively, and that subjects with plaque erosion had greater evidence of subacute thrombus.

Coronary Plaque Erosion: Epidemiology, Diagnosis, and Treatment

Plaque erosion (PE), a distinct etiology of acute coronary syndromes (ACSs), is often overshadowed by plaque ruptures (PRs). Concerning its epidemiology, PE has garnered increasing recognition, with recent studies revealing its prevalence to be approximately 40% among ACS patients, challenging earlier assumptions based on autopsy data. Notably, PE exhibits distinct epidemiological features, preferentially affecting younger demographics, particularly women, and often manifesting as a non-ST-segment elevation myocardial infarction. There are seasonal variations, with PE events being less common in winter, potentially linked to physiological changes and cholesterol solidification, while peaking in summer, warranting further investigation. Moving to molecular mechanisms, PE presents a unique profile characterized by a lesser degree of inflammation compared to PR, with endothelial shear stress emerging as a plausible molecular mechanism. Neutrophil activation, toll-like receptor-2 pathways, and hyaluronidase 2 expression are among the factors implicated in PE pathophysiology, underscoring its multifactorial nature. Advancements in intravascular imaging diagnostics, particularly optical coherence tomography and near-infrared spectroscopy coupled with intravascular ultrasound, offer unprecedented insights into plaque composition and morphology. Artificial intelligence algorithms show promise in enhancing diagnostic accuracy and streamlining image interpretation, augmenting clinician decision-making. Therapeutically, the management of PE evolves, with studies exploring less invasive approaches such as antithrombotic therapy without stenting, particularly in cases identified early through intravascular imaging. Additionally, the potential role of drug-coated balloons in reducing thrombus burden and minimizing future major adverse cardiovascular events warrants further investigation. Looking ahead, the integration of advanced imaging modalities, biomarkers, and artificial intelligence promises to revolutionize the diagnosis and treatment of coronary PE, ushering in a new era of personalized and precise cardiovascular care.

Unusual optical coherence tomography findings resembling sea anemone tentacles after orbital atherectomy for nodular calcification lesions in a haemodialysis patient: a case report

Background

Optical coherence tomography (OCT) can be used to characterize the details of calcified plaques because it allows high-resolution evaluation of coronary plaques, thrombi, and calcium.

Case summary

A 72-year-old man on haemodialysis who had stenosis with a severe calcified lesion at the left anterior descending artery underwent percutaneous coronary intervention. Pre-intervention OCT imaging identified a nodular calcification (NC) that protruded into the lumen of the left anterior descending artery. To treat this lesion, we performed orbital atherectomy using the Diamondback 360 coronary orbital atherectomy system. After ablation of the nodular lesions at low and high speed, OCT showed newly emerged granular and filamentous structures that resembled sea anemone tentacles (these represented calcified nodule-like OCT findings). These structures appeared to extend from the proximal part of the ablated small NC, and shifted distally after balloon dilatation. Stent implantation was performed to entirely cover these structures, with no resulting complications. However, early in-stent restenosis occurred at 4 months follow-up.

Discussion

A tentacle-like OCT appearance in calcified lesions has not been previously reported. This represents a very rare and interesting imaging finding that reflects the relationship and origins of NCs and calcified nodules. The maturity of the NC lesions and the lateral sanding style of the orbital atherectomy system may have contributed to this striking OCT finding.