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We assessed the relationship between exposure to air pollutants and mechanisms of coronary instability evaluated by optical coherence tomography (OCT) in patients with acute coronary syndrome (ACS). Air pollution is an emerging key player in determining the residual risk of coronary events. However, pathophysiological mechanisms linking air pollution and coronary events have been not adequately investigated. Patients with ACS undergoing OCT imaging were retrospectively selected. Mechanism of culprit lesion instability was classified as plaque rupture (PR) or intact fibrous cap (IFC) by OCT, and the presence of macrophage infiltrates (MØI) and thin-cap fibroatheroma (TCFA) at the culprit site was also assessed. Based on each case's home address, exposure to several pollutants was evaluated, including particulate matter 2.5 (PM2.5), PM10, and carbon monoxide (CO). Only patients with >2 years of available data on air pollution exposure prior to ACS were enrolled. We included 126 patients (median age: 67.0 years of age; IQR: 55.5-76.0; 97 male patients [77.0%]). Sixty-six patients (52.4%) had PR as the mechanism of plaque instability. Patients with PR were exposed to significantly higher PM2.5 levels than to IFC, and PM2.5 was independently associated with PR (odds ratio: 1.194; 95% CI: 1.036 to 1.377; P = 0.015). Moreover, exposure to higher levels of PM2.5 was independently associated with the presence of TCFA and of MØI at the culprit site. Interestingly, PM2.5, PM10, and C o levels were positively and significantly correlated with serum levels of C-reactive protein. We provide novel insights into the missing link between air pollution and increased risk of coronary events. In particular, exposure to higher concentrations of air pollutants is associated with the presence of vulnerable plaque features and with plaque rupture as a mechanism of coronary instability. An enhanced systemic and plaque inflammatory activation may explain these findings. [Display omitted] [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) represents a heterogeneous clinical conundrum accounting for about 6%-8% of all acute MI who are referred for coronary angiography. Current guidelines and consensus documents recommend that these patients are appropriately diagnosed, uncovering the causes of MINOCA, so that specific therapies can be prescribed. Indeed, there are a variety of causes that can result in this clinical condition, and for this reason diagnostic cardiac imaging has an emerging critical role in the assessment of patients with suspected or confirmed MINOCA. In last years, different cardiac imaging techniques have been evaluated in this context, and the comprehension of their strengths and limitations is of the utmost importance for their effective use in clinical practice. Moreover, recent evidence is clearly suggesting that a multimodality cardiac imaging approach, combining different techniques, seems to be crucial for a proper management of MINOCA. However, great variability still exists in clinical practice in the management of patients with suspected MINOCA, also depending on the availability of diagnostic tools and local expertise. Herein, we review the current knowledge supporting the use of different cardiac imaging techniques in patients with MINOCA, underscoring the importance of a comprehensive multimodality cardiac imaging approach and proposing a practical diagnostic algorithm to properly identify and treat the specific causes of MINOCA, in order to improve prognosis and the quality of life in these patients. [ABSTRACT FROM AUTHOR]

Macrophages play a key role in coronary plaque destabilization. In-vitro human monocyte-derived macrophages (MDMs) are used to study macrophages infiltrating tissue. Optical coherence tomography (OCT) provides an in-vivo insight of the coronary arteries. We compared the MDMs morpho-phenotype and culprit plaque features at OCT in acute coronary syndrome (ACS) patients according to the underlying plaque pathobiology. Sixty-six patients undergoing coronary angiography and pre-angioplasty OCT of the culprit vessel were allocated to three groups according to mechanism of ACS at OCT and C-reactive protein levels (cut-off: 2 mg/Ll): 1) plaque rupture with systemic inflammation; 2) plaque rupture without systemic inflammation, 3) plaque with intact fibrous cap. A blood sample was collected to obtain MDMs, categorized as having "round" or "spindle" morphology. Thirty-two patients (48.5%) were assigned to Group 1, 10 (15.2%) to Group 2 and 24 (36.4%) to Group 3. The "round" MDMs were significantly more frequent in Group 1 (39.25 ± 4.98%) than in Group 2 (23.89 ± 3.10%) and Group 3 (23.02 ± 7.89%), p = 0.008. MDMs in Group 1 as compared to Groups 2 and 3 showed lower efferocytosis (8.74 ± 1.38 vs 9.74 ± 2.15 vs 11.41 ± 2.41; p = 0.012), higher tissue factor levels (369.84 ± 101.13 vs 301.89 ± 59.78 vs 231.74 ± 111.47; p = 0.001) and higher heme oxygenase-1 expression (678.78 ± 145.43 vs 419.12 ± 74.44 vs 409.78 ± 64.33; p = 0.008). MDMs of ACS patients show morpho-phenotypic heterogeneity with prevalence of pro-thrombotic and pro-oxidative properties in case of plaque rupture and systemic inflammation. Such MDMs subpopulation may take part to the cellular pathways leading to fibrous cap rupture with the subsequent thrombus formation. • Monocyte-derived macrophages to study macrophages infiltrating coronary plaques. • Optical Coherence Tomography to identify the mechanism of plaque destabilization. • Pro-thrombotic, oxidative macrophages are prevalent in ruptures with inflammation. [ABSTRACT FROM AUTHOR]

Patients with acute coronary syndrome (ACS) associated to high C-reactive protein (CRP) levels exhibit a higher risk of future acute ischemic events. Yet, the positive predictive value of CRP is too low to guide a specific treatment. Our study aims to identify a high-risk patient subset who might mostly benefit from anti-inflammatory treatment on the basis of the combination of optical coherence tomography (OCT) assessment of the culprit vessel and CRP serum levels. Patients admitted for ACS and undergoing pre-interventional OCT assessment of the culprit vessel were selected from "Agostino Gemelli" Hospital OCT Registry. The primary end-point was recurrent ACS (re-ACS). CRP levels ≥2 mg/L were considered abnormal. The overall study population consisted of 178 patients. Among these, 156 patients were included in the primary end-point analysis. The re-ACS rate was 23% at 3-year follow-up. High CRP (2.587, 95% CI:1.345–10.325, p = 0.031), plaque rupture (3.985, 95% CI:1.698–8.754, p = 0.009), macrophage infiltration (3.145, 95% CI:1.458–9.587, p = 0.012) and multifocal atherosclerosis (2.734, 95% CI:1.748–11.875, p = 0.042) were independent predictors of re-ACS. All patients (14/14) with high CRP and with all OCT high-risk features had re-ACS. At the other extreme, only 4 of the 82 patients with low CRP levels and lack of high-risk features at OCT examination exhibited re-ACS at follow-up. The combination of systemic evidence of inflammation and OCT findings in the culprit plaque identifies very high-risk ACS. Future studies are warranted to confirm these findings and to test an anti-inflammatory treatment in this patient subset. • High CRP and OCT features of the culprit vessel predict recurrent coronary events. • Patients with high-risk OCT features and high CRP experienced a recurrent ACS. • Our findings may contribute to individualize the secondary prevention of ACS. [ABSTRACT FROM AUTHOR]

Patients with an acute coronary syndrome (ACS) due to plaque rupture had a worse prognosis when compared with those without plaque rupture with a higher rate of target vessel revascularization and readmission for unstable angina, suggesting that both stent failure and disease progression occur more frequently. However, it is not known whether recurrent episodes of coronary instability in the same patient are caused by the same pathogenetic mechanism. Thus, we sought to investigate the mechanisms of coronary instability imaged by optical coherence tomography in patients with recurrent ACS events. The present case series, with 4 patients having recurrent ACS, shows that the same mechanism of coronary instability is present during both first and recurrent instability. This hypothesis-generating finding may support further studies targeted at assessing the mechanisms of coronary instability recurrence and how to tailor preventive measures to the underlying mechanism of instability. [ABSTRACT FROM AUTHOR]

Background Lipoprotein Lp(a) has been shown to be an independent risk factor for coronary artery disease (CAD). However, its association with CAD burden in patients with ACS is largely unknown, as well as the association of Lp(a) with lipid rich plaques prone to rupture. Aim We aim at assessing CAD burden by coronary angiography and plaque features including thin cap fibroatheroma (TCFA) by optical coherence tomography (OCT) in consecutive patients presenting with acute coronary syndrome (ACS) and obstructive CAD along with serum Lp(a) levels. Methods This study comprises an angiographic and an OCT cohort. A total of 500 ACS patients (370 men, average age 66 ± 11) were enrolled for the angiographic cohort and 51 ACS patients (29 males, average age 65 ± 11) were enrolled for the OCT cohort. Angiographic CAD severity was assessed by Sullivan score and by Bogaty score including stenosis score and extent index. OCT plaque features were evaluated at the site of the minimal lumen area and along the culprit segment. Results In the angiographic cohort, at multivariate analysis, Lp(a) was a weak independent predictor of Sullivan score (p < 0.0001), stenosis score (p < 0.0001) and extent index (p < 0.0001). In the OCT cohort, patients with higher Lp(a) levels (≥30 md/dl) compared to patients with lower Lp(a) levels (<30 md/dl) exhibited a higher prevalence of lipidic plaque at the site of the culprit stenosis (67% vs. 27%; P = 0.02), a wider lipid arc (135 ± 114 vs 59 ± 111; P = 0.03) and a higher prevalence of TCFA (38% vs. 10%; P = 0.04). Conclusions Among patients with ACS, raised Lp(a) levels are associated with an increased atherosclerotic burden and it identifies a subset of patients with features of high risk coronary atherosclerosis. [ABSTRACT FROM AUTHOR]

Air pollution is emerging as an important risk factor for acute coronary syndrome (ACS). In this study, we investigated the association between short-term air pollution exposure and mechanisms of coronary plaque instability evaluated by optical coherence tomography (OCT) imaging in ACS patients. Patients with ACS undergoing OCT imaging were retrospectively selected. Mechanism of culprit lesion instability was classified as plaque rupture (PR) or intact fibrous cap (IFC) by OCT. Based on each case's home address, the mean daily exposures to several pollutants, including particulate matter 2.5 (PM 2.5), on the same day of ACS and in the immediate days (up to 6 days) prior to the index ACS, were collected. 139 ACS patients were included [69 (49.6%) had PR and 70 (50.4%) IFC]. Patients with PR, compared to those with IFC, had higher PM 2.5 exposure levels on the same day of ACS, without differences in the immediate 6 days before index ACS. At multivariate analysis, PM 2.5 exposure on the same day of ACS was the only independent predictor of PR [OR = 1.912 per SD (8.6 μg/m3), CI95 % (1.087–3.364), p = 0.025]. Patients with PR presented a steady increase in PM 2.5 daily exposure levels in the days preceding the occurrence of ACS, with a peak the day of ACS (p for trend = 0.042) This study demonstrates for the first time that a higher short-term PM2.5 exposure, on the same day of ACS, is associated with an increased risk of PR as a pathobiological mechanism of coronary plaque instability. [Display omitted] • Air pollution is emerging as an important risk factor for acute coronary syndrome (ACS). • Acute PM 2.5 exposure, especially on the same day of ACS, is associated with an increased risk of plaque rupture as mechanism of coronary plaque instability. • Mitigation strategies are crucial to reduce the burden of ischemic heart disease, especially in patients with a higher risk of cardiovascular events. [ABSTRACT FROM AUTHOR]

Plaque erosion (PE) is responsible for at least one-third of acute coronary syndrome (ACS), and inflammation plays a key role in plaque instability. We assessed the presence of optical coherence tomography (OCT)-defined macrophage infiltrates (MØI) at the culprit site in ACS patients with PE, evaluating their clinical and OCT correlates, along with their prognostic value. ACS patients undergoing OCT imaging and presenting PE as culprit lesion were retrospectively selected. Presence of MØI at culprit site was assessed. The incidence of major adverse cardiac events (MACEs), defined as the composite of cardiac death, recurrent myocardial infarction and target-vessel revascularization (TVR), was assessed [follow-up median (interquartile range, IQR) time 2.5 (2.03–2.58) years]. We included 153 patients [median age (IQR) 64 (53–75) years, 99 (64.7%) males]. Fifty-one (33.3%) patients presented PE with MØI and 102 (66.7%) PE without MØI. Patients having PE with MØI compared with PE patients without MØI had more vulnerable plaque features both at culprit site and at non-culprit segments. MACEs were significantly more frequent in PE with MØI patients compared with PE without MØI [11 (21.6%) vs. 6 (5.9%), p = 0.008], mainly driven by a higher risk of cardiac death and TVR. At multivariable Cox regression, PE with MØI was an independent predictor of MACEs [HR = 2.95, 95% CI (1.09–8.02), p = 0.034]. Our study demonstrates that among ACS patients with PE the presence of MØI at culprit lesion is associated with more vulnerable plaque features, along with a worse prognosis at a long-term follow-up. Image 1 • Presence of macrophage infiltrates (MØI) at erosion sites is associated with vulnerable coronary plaque features. • Presence of plaque erosion (PE) with MØI is associated with a worse prognosis at long-term follow-up. • Worse prognosis in patients with MØI was mainly driven by a higher risk of cardiac death and target-vessel revascularization (TVR). • Progression of non-culprit lesions may be involved in determining prognosis in patients with MØI. [ABSTRACT FROM AUTHOR]

Dual quantitative coronary angiography (QCA) has been recently tested for assessment of intracoronary thrombus volume in experimental models. The present study aimed to validate dual QCA in vivo for the assessment of thrombus burden by exploring the correlations between dual QCA-thrombus volume and optical coherence tomography (OCT)-derived indices of thrombotic burden. Fifty-one patients with ACS and angiographic evidence of thrombus undergoing OCT of the culprit lesion before stenting were included. Dual QCA-thrombus volume was calculated as difference between edge-detection and video-densitometry area functions along the target segment. Culprit lesion was categorized using the Ambrose's and AHA/ACC angiographic classifications. Thrombus volume (mean thrombus area × thrombus length), thrombus burden [(mean thrombus area/mean lumen area) x100] and Prati thrombus score (number of quadrants with thrombus) were measured by OCT, and the presence of plaque rupture (PR) or intact fibrous cap (IFC) was assessed. Dual QCA-thrombus volume correlated significantly with OCT-thrombus volume (R = 0.791), thrombus burden (R = 0.767) and Prati thrombus score (R = 0.600) (all p < 0.001). Dual-QCA thrombus volume was significantly higher in patients with PR compared with those with IFC (3.48 mm3 [1.45–11.26] vs. 1.69 mm3 [0.09–5.02], p = 0.013). Compared with IFC, PR showed higher prevalence of eccentric type II Ambrose lesion (41.7% vs. 7.4%, p = 0.004), complex B2/C lesion (87.5% vs. 55.6%, p = 0.012), and heavy calcification (29.2% vs. 3.7%, p = 0.013). Dual QCA analysis appears to be a promising tool for quantification of intracoronary thrombus in vivo. This novel methodology may be useful to guide intracoronary thrombus removal during percutaneous coronary intervention and to aid prognostic stratification in patients with ACS. Unlabelled Image • Dual quantitative coronary angiography (QCA) has been tested for the assessment of thrombus volume in experimental models. • In this in vivo study, dual QCA-thrombus volume was correlated with optical coherence tomography indices of thrombus burden. • A combination of angiographic features may enable the discrimination of patients with plaque rupture and intact fibrous cap. • Dual QCA may be useful to guide thrombus removal and aid prognostic stratification in patients with acute coronary syndrome. [ABSTRACT FROM AUTHOR]

Background: Optical-coherence-tomography (OCT) is an emerging invasive coronary imaging with still undefined clinical value. Recent data have underlined daily impact of such technique in several clinical settings such as acute coronary syndromes (ACS) and percutaneous coronary intervention (PCI) guidance. We aimed at assessing the trends and outcomes of OCT use in a high-volume percutaneous coronary interventions (PCI)-center.Methods: Over 6 years, 1025 coronary artery segments in 877 patients underwent OCT evaluation. Clinical and procedural characteristics were prospectively collected. Clinical setting for OCT was: "Diagnostic OCT" (OCT for lesion evaluation after coronary angiography without further PCI); "PCI-guidance OCT" (OCT as a guidance for complex PCI, both by intention or after diagnostic OCT). Primary study end-point was the occurrence of target-vessel-failure (TVF) during the follow-up.Results: Overall, OCT was successful in 99.1% of attempted lesions. Only one complication (coronary dissection requiring urgent PCI) occurred during OCT. After a follow-up of 695 ± 562 days, TVF occurred in 8.2% of cases. Despite similar baseline characteristics, TVF-free survival curves were different in the two populations (5.4% after diagnostic OCT and 9.9% after PCI-guidance OCT). Minimal-lumen-area (MLA) of target lesion was independently associated with TVF (HR 0.7, 95% CI 0.6-0.8). This was mainly driven by a significant impact of MLA in patients not revascularized (HR 0.6, 95% CI 0.4-0.9). TVF did not change according to the study period despite the selection of patients with increasing complexity.Conclusions: OCT has a good safety profile across a broad spectrum of patients encountered in daily practice. The easy-to-assess MLA parameter may help stratify prognosis of patients undergoing OCT. These data call for further evaluations of OCT clinical impact.Summary: OCT is a light-based imaging tool which had subvert the quite ordinary world of coronary imaging and the present study evaluates OCT use in a high-volume center. Our results suggest that application of OCT in "real world" patients presenting higher risk has a good safety profile. Several factors could predict a worse long-term outcome in patients undergoing OCT evaluation, mostly related to more complex clinical conditions. These findings could encourage even low-to intermediate volume centers to improve their OCT use in daily practice. [ABSTRACT FROM AUTHOR]

Abstract Background A sizeable proportion of patients with Acute Coronary Syndromes (ACS) shows a unique adaptive immune system profile, associated to a worse outcome, characterized by higher CD4+CD28null T-cells, lower regulatory T-cells (Treg) and increased CD4+CD28null/Treg ratio. We sought to investigate the correlation between CD4+CD28null T-cells, Treg, CD4+CD28null/Treg ratio and plaque phenotype as assessed by Optical Coherence Tomography (OCT). Methods Peripheral blood mononuclear cells (PBMC) were collected from 30 Non-ST Elevation Myocardial Infarction (NSTEMI) patients, sub-grouped according to OCT analysis of culprit lesions into two cohorts: Ruptured Fibrous Cap (NSTEMI-RFC, n = 12) and Intact Fibrous Cap (NSTEMI-IFC, n = 18). Stable Angina patients (SA, n = 18) were used as controls. We examined the frequency of CD4+CD28null and Treg (defined as CD4+CD25highCD127lowFoxp3+ T-cells) by flow-cytometry. Results CD4+CD28null frequency (median, range) was significantly higher in NSTEMI-RFC patients (17.3%, 12.5–33.8) as compared with NSTEMI-IFC (3.8%, 0.3–14.1) and SA (3%, 0.6–17.7) (P < 0.001 for all comparisons). We also found a higher CD4+CD28null/Treg ratio in NSTEMI-RFC patients (6.6%, 3.7–13.9) than in NSTEMI-IFC (1.6%, 0.3–5.2) and SA (1.2%, 0.3–8.7) (P < 0.001 for all comparisons). Finally, there was an inverse correlation between CD4+CD28null/Treg ratio and cap-thickness (R = −0.44; P = 0.002). Conclusion Patients with NSTEMI presenting with RFC as culprit lesion at OCT evaluation have a specific perturbation of adaptive immunity, mostly involving CD4+CD28null T- cells and Tregs, as compared with patients with IFC and SA. This specific imbalance of T-cells might play a key role in fibrous cap thinning, predisposing atherosclerotic plaque to rupture. Highlights • Plaque rupture at OCT evaluation is associated to a specific adaptive immune system signature. • A deeper perturbation of adaptive immunity might be involved in fibrous cap thinning. • Molecular and morphological plaque phenotyping might be a new frontier for personalized medicine. [ABSTRACT FROM AUTHOR]

Background The decision-making process of patients with angiographically-intermediate coronary lesions (ICL) is clinically challenging and may benefit from adjunctive invasive techniques. Fractional-flow-reserve (FFR) represents the gold standard to evaluate ICL but frequency-domain optical-coherence-tomography (OCT) is a novel, promising, high resolution coronary imaging technique, which allows physiopathologic assessment of coronary plaque. We investigated the possible relation between OCT and FFR in selected ICL patients. Methods Stable or unstable patients with ICL who underwent both FFR and OCT assessment at two large tertiary centers were retrospectively enrolled. FFR was performed according to standard methodology. OCT images were (on blind to clinical and FFR results) analyzed to assess minimal lumen area (MLA), percentage area stenosis (AS), thrombus and plaque ulceration. Results Forty patients were identified (62 ± 10 years, 93% symptomatic, 35% acute presentation, 93% left-anterior-descending artery ICL). Percentage diameter stenosis at quantitative coronary angiography was 40 ± 12% and FFR was 0.85 ± 0.07. MLA ( p = 0.009), AS ( p < 0.001) and plaque ulceration ( p = 0.02) were significantly associated with FFR values. An integrated assessment of AS (≥ or < 70%), MLA (≥ or < 2.5 mm 2 ) and presence or absence of thrombus and plaque ulceration was found to have the potential to accurately (sensitivity 91%, specificity 93%) predict FFR results. Conclusion In patients with ICL, a combination of different OCT parameters may help predict FFR results. These findings suggest that only a comprehensive assessment of lesion features by OCT can allow an accurate prediction of lesion severity assessed by FFR. [ABSTRACT FROM AUTHOR]

Background Left main (LM) atherosclerotic lesions affect clinical outcomes. Frequency domain-optical coherence tomography (FD-OCT) allows detailed characterization of non-ostial coronary atherosclerotic lesions. The clinical impact of FD-OCT assessment of LM bifurcation disease on the revascularization decision is unknown. Methods Patients who underwent FD-OCT assessment to guide management of angiographically intermediate distal LM stenosis were retrospectively selected. The FD-OCT LM criteria for percutaneous or surgical revascularization were: – LM area stenosis (AS) ≥ 75% – LM AS > 50% < 75% with minimum lumen area < 4 mm 2 or plaque ulceration – critical FD-OCT ostial stenosis on the left anterior descending or circumflex arteries. Clinical follow-up was obtained to evaluate the occurrence of target vessel failure (TVF) defined as cardiac death and/or acute myocardial infarction (AMI) not related to other vessel and/or target vessel revascularization. Results Out of 131 patients underwent FD-OCT assessment of LM, 122 patients (93%) entered the study. Based on FD-OCT features, 58 (48%) patients were conservatively managed, while the remaining 64 (52%) were revascularized by stenting (n = 48) or surgery (n = 16). After a mean follow-up of 18 months, TVF-free survival was not different between patients undergoing conservative management vs. revascularization (HR 0.40, CI 95% 0.10–1.61, P = 0.20). Of note, two patients only in the conservative management group had TVF (elective LM stenting, no death or myocardial infarction). Conclusions This preliminary experience suggests that a FD-OCT based management for patients with angiographically-intermediate LM bifurcation stenosis may help identify patients in whom revascularization could be deferred. Such observation calls for further evaluations by appropriately designed trials. [ABSTRACT FROM AUTHOR]

Aim To compare in patients with ACS (acute coronary syndromes) a PCI (percutaneous coronary intervention) approach based on FFR (fractional flow reserve) vs. one based on OCT (optical coherence tomography). Methods and results Consecutive patients admitted for ACS and treated with a PCI approach based on OCT or on FFR (recruited in two different studies) were compared and matched with propensity score analysis. Target Lesion revascularization (TLR) was the primary end point, while major adverse cardiovascular events [MACEs defined as the composite of death from cardiac causes, non-fatal MI, clinically driven target vessel revascularization (TVR), or re-hospitalization due to unstable angina] were the secondary ones. Sub-group analysis was performed for patients with FFR/OCT performed on culprit lesions and not. 285 patients were enrolled in the OCT-guided group and 335 in the FFR-guided group, 197 for each being selected after propensity score. After 25 months (range: 7–39 months), OCT-guided group were exposed to lower incidence of TLR (4.1% vs. 14.2% p < 0.01) compared with FFR-guided group without impact on MACEs (14.2% vs. 14.2%, p = 1) or all-cause death (3.6% vs. 1.1%, p = 0.34). At Kaplan-Maier curve analysis for MACEs OCT-guided and FFR-guided groups showed similar outcomes (HR 1.19, CI 0.65–2.2, p = 0.54). Subgroup analysis on culprit and not culprit vessel demonstrated consistent results. Conclusions An OCT based approach in ACS patients offers a reduction in TLR when compared to a PCI-FFR driven. These findings should be confirmed in randomized controlled trial. [ABSTRACT FROM AUTHOR]

Background Endothelialisation is a crucial event after percutaneous coronary intervention (PCI). Endothelial progenitor cells (EPCs) are bone marrow derived elements with reparative properties. We aimed to assess the relationship between circulating EPC levels and stent neointimal hyperplasia (NIH) using frequency domain optical coherence tomography (FD-OCT). Methods Patients undergoing elective PCI to native vessels and randomised to bare metal stent (BMS) alone versus BMS plus drug coated balloon (DCB) were included. At six months, angiographic follow-up and FD-OCT were performed to measure percentage neointimal hyperplasia volume obstruction (%NIHV), and percentage of uncovered stent struts (%US). Venous blood samples were obtained before the procedure and at six months to detect CD34+CD45dimKDR + EPC levels. Results Twenty patients were enrolled. A significant relationship was observed between baseline EPC levels and %NIHV (R: 0.63, p: 0.03) and %US (R: − 0.56, p: 0.01) at follow-up. Both EPC levels and DCB use were independently related to %NIHV (β: 0.55; p < 0.001 and β: − 0.51; p: 0.001, respectively), while only EPC levels were independently associated to %US (β: − 0.52; p: 0.01). Higher %NIHV (p: 0.004) and lower %US (p: 0.005) were observed in patients with stable or increasing EPC level. Conclusion Our study shows a relationship between EPC levels and stent strut coverage, supporting a dual role for these cells in favouring stent endothelialisation but also NIH growth. [ABSTRACT FROM AUTHOR]

Abstract: Stent thrombosis (ST) is the most dramatic complication of coronary stenting. Mechanisms of ST are multiple, including procedural and patient-related factors. A considerable burden of metal inside the coronary has been associated with ST as suggested by the higher rate of ST in case of multiple overlapping or complex two stents procedure in bifurcation lesions. However, occasional stent loss and failure to retrieve it may be a substrate of ST, especially if multiple layers of stent struts are incompletely crushed. Here, we describe a case of very late ST on a partially crushed stent previously lost inside the coronary circulation, using optical coherence tomography (OCT) for guidance during the procedure. [Copyright &y& Elsevier]