Distinct developmental pathways from blood monocytes generate human lung macrophage diversity.

The study of human macrophages and their ontogeny is an important unresolved issue. Here, we use a humanized mouse model expressing human cytokines to dissect the development of lung macrophages from human hematopoiesis in vivo. Human CD34+ hematopoietic stem and progenitor cells (HSPCs) generated three macrophage populations, occupying separate anatomical niches in the lung. Intravascular cell labeling, cell transplantation, and fate-mapping studies established that classical CD14+ blood monocytes derived from HSPCs migrated into lung tissue and gave rise to human interstitial and alveolar macrophages. In contrast, non-classical CD16+ blood monocytes preferentially generated macrophages resident in the lung vasculature (pulmonary intravascular macrophages). Finally, single-cell RNA sequencing defined intermediate differentiation stages in human lung macrophage development from blood monocytes. This study identifies distinct developmental pathways from circulating monocytes to lung macrophages and reveals how cellular origin contributes to human macrophage identity, diversity, and localization in vivo.

The complement alternative pathway in paroxysmal nocturnal hemoglobinuria: From a pathogenic mechanism to a therapeutic target.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal, not malignant, hematological disease characterized by intravascular hemolysis, thrombophilia and bone marrow failure. While this latter presentation is due to a T-cell mediated auto-immune disorder resembling acquired aplastic anemia, the first two clinical presentations are largely driven by the complement pathway. Indeed, PNH is characterized by a broad impairment of complement regulation on affected cells, which is due to the lack of the complement regulators CD55 and CD59. The deficiency of these two proteins from PNH blood cells is due to the somatic mutation in the phosphatidylinositol N-acetylglucosaminyltransferase subunit A gene causing the disease, which impairs the surface expression of all proteins linked via the glycosylphosphatidylinositol anchor. The lack of the complement regulators CD55 and CD59 on PNH erythrocytes accounts for the hallmark of PNH, which is the chronic, complement-mediated intravascular hemolysis. This hemolysis results from the impaired regulation of the alternative pathway upstream in the complement cascade, as well as of the downstream terminal pathway. PNH represented the first indication for the development of anti-complement agents, and the therapeutic interception of the complement cascade at the level of C5 led to remarkable changes in the natural history of the disease. Nevertheless, the clinical use of an inhibitor of the terminal pathway highlighted the broader derangement of complement regulation in PNH, shedding light on the pivotal role of the complement alternative pathway. Here we review the current understanding of the role of the alternative pathway in PNH, including the emergence of C3-mediated extravascular hemolysis in PNH patients on anti-C5 therapies. These observations provide the rationale for the development of novel complement inhibitors for the treatment of PNH. Recent preclinical and clinical data on proximal complement inhibitors intercepting the alternative pathway with the aim of improving the treatment of PNH are discussed, together with their clinical implications which are animating a lively debate in the scientific community.

Discovering C3 targeting therapies for paroxysmal nocturnal hemoglobinuria: Achievements and pitfalls.

The treatment of paroxysmal nocturnal hemoglobinuria (PNH) was revolutionized by the introduction of the anti-C5 agent eculizumab, which resulted in sustained control of intravascular hemolysis, leading to transfusion avoidance and hemoglobin stabilization in at least half of all patients. Nevertheless, extravascular hemolysis mediated by C3 has emerged as inescapable phenomenon in PNH patients on anti-C5 treatment, frequently limiting its hematological benefit. More than 10 years ago we postulated that therapeutic interception of the complement cascade at the level of C3 should improve the clinical response in PNH. Compstatin is a 13-residue disulfide-bridged peptide binding to both human C3 and C3b, eventually disabling the formation of C3 convertases and thereby preventing complement activation via all three of its activating pathways. Several generations of compstatin analogs have been tested in vitro, and their clinical evaluation has begun in PNH and other complement-mediated diseases. Pegcetacoplan, a pegylated form of the compstatin analog POT-4, has been investigated in two phase I/II and one phase III study in PNH patients. In the phase III study, PNH patients with residual anemia already on eculizumab were randomized to receive either pegcetacoplan or eculizumab in a head-to-head comparison. At week 16, pegcetacoplan was superior to eculizumab in terms of hemoglobin change from baseline (the primary endpoint), as well as in other secondary endpoints tracking intravascular and extravascular hemolysis. Pegcetacoplan showed a good safety profile, even though breakthrough hemolysis emerged as a possible risk requiring additional attention. Here we review all the available data regarding this innovative treatment that has recently been approved for the treatment of PNH.

Intracapillary LPL levels in brown adipose tissue, visualized with an antibody-based approach, are regulated by ANGPTL4 at thermoneutral temperatures.

Lipoprotein lipase (LPL) is secreted into the interstitial spaces by parenchymal cells and then transported into capillaries by GPIHBP1. LPL carries out the lipolytic processing of triglyceride (TG)-rich lipoproteins (TRLs), but the tissue-specific regulation of LPL is incompletely understood. Plasma levels of TG hydrolase activity after heparin injection are often used to draw inferences about intravascular LPL levels, but the validity of these inferences is unclear. Moreover, plasma TG hydrolase activity levels are not helpful for understanding LPL regulation in specific tissues. Here, we sought to elucidate LPL regulation under thermoneutral conditions (30 °C). To pursue this objective, we developed an antibody-based method to quantify (in a direct fashion) LPL levels inside capillaries. At 30 °C, intracapillary LPL levels fell sharply in brown adipose tissue (BAT) but not heart. The reduced intracapillary LPL levels were accompanied by reduced margination of TRLs along capillaries. ANGPTL4 expression in BAT increased fourfold at 30 °C, suggesting a potential explanation for the lower intracapillary LPL levels. Consistent with that idea, Angptl4 deficiency normalized both LPL levels and TRL margination in BAT at 30 °C. In Gpihbp1-/- mice housed at 30 °C, we observed an ANGPTL4-dependent decrease in LPL levels within the interstitial spaces of BAT, providing in vivo proof that ANGPTL4 regulates LPL levels before LPL transport into capillaries. In conclusion, our studies have illuminated intracapillary LPL regulation under thermoneutral conditions. Our approaches will be useful for defining the impact of genetic variation and metabolic disease on intracapillary LPL levels and TRL processing.

Inverse effects of APOC2 and ANGPTL4 on the conformational dynamics of lid-anchoring structures in lipoprotein lipase.

The lipolytic processing of triglyceride-rich lipoproteins (TRLs) by lipoprotein lipase (LPL) is crucial for the delivery of dietary lipids to the heart, skeletal muscle, and adipose tissue. The processing of TRLs by LPL is regulated in a tissue-specific manner by a complex interplay between activators and inhibitors. Angiopoietin-like protein 4 (ANGPTL4) inhibits LPL by reducing its thermal stability and catalyzing the irreversible unfolding of LPL's α/ß-hydrolase domain. We previously mapped the ANGPTL4 binding site on LPL and defined the downstream unfolding events resulting in LPL inactivation. The binding of LPL to glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 protects against LPL unfolding. The binding site on LPL for an activating cofactor, apolipoprotein C2 (APOC2), and the mechanisms by which APOC2 activates LPL have been unclear and controversial. Using hydrogen-deuterium exchange/mass spectrometry, we now show that APOC2's C-terminal α-helix binds to regions of LPL surrounding the catalytic pocket. Remarkably, APOC2's binding site on LPL overlaps with that for ANGPTL4, but their effects on LPL conformation are distinct. In contrast to ANGPTL4, APOC2 increases the thermal stability of LPL and protects it from unfolding. Also, the regions of LPL that anchor the lid are stabilized by APOC2 but destabilized by ANGPTL4, providing a plausible explanation for why APOC2 is an activator of LPL, while ANGPTL4 is an inhibitor. Our studies provide fresh insights into the molecular mechanisms by which APOC2 binds and stabilizes LPL-and properties that we suspect are relevant to the conformational gating of LPL's active site.

Coronary Angiography, Intravascular Ultrasound, and Optical Coherence Tomography for Guiding of Percutaneous Coronary Intervention: A Systematic Review and Network Meta-Analysis.

BACKGROUND: Results from multiple randomized clinical trials comparing outcomes after intravascular ultrasound (IVUS)- and optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) with invasive coronary angiography (ICA)-guided PCI as well as a pivotal trial comparing the 2 intravascular imaging (IVI) techniques have provided mixed results. METHODS: Major electronic databases were searched to identify eligible trials evaluating at least 2 PCI guidance strategies among ICA, IVUS, and OCT. The 2 coprimary outcomes were target lesion revascularization and myocardial infarction. The secondary outcomes included ischemia-driven target lesion revascularization, target vessel myocardial infarction, death, cardiac death, target vessel revascularization, stent thrombosis, and major adverse cardiac events. Frequentist random-effects network meta-analyses were conducted. The results were replicated by Bayesian random-effects models. Pairwise meta-analyses of the direct components, multiple sensitivity analyses, and pairwise meta-analyses IVI versus ICA were supplemented. RESULTS: The results from 24 randomized trials (15 489 patients: IVUS versus ICA, 46.4%, 7189 patients; OCT versus ICA, 32.1%, 4976 patients; OCT versus IVUS, 21.4%, 3324 patients) were included in the network meta-analyses. IVUS was associated with reduced target lesion revascularization compared with ICA (odds ratio [OR], 0.69 [95% CI, 0.54-0.87]), whereas no significant differences were observed between OCT and ICA (OR, 0.83 [95% CI, 0.63-1.09]) and OCT and IVUS (OR, 1.21 [95% CI, 0.88-1.66]). Myocardial infarction did not significantly differ between guidance strategies (IVUS versus ICA: OR, 0.91 [95% CI, 0.70-1.19]; OCT versus ICA: OR, 0.87 [95% CI, 0.68-1.11]; OCT versus IVUS: OR, 0.96 [95% CI, 0.69-1.33]). These results were consistent with the secondary outcomes of ischemia-driven target lesion revascularization, target vessel myocardial infarction, and target vessel revascularization, and sensitivity analyses generally did not reveal inconsistency. OCT was associated with a significant reduction of stent thrombosis compared with ICA (OR, 0.49 [95% CI, 0.26-0.92]) but only in the frequentist analysis. Similarly, the results in terms of survival between IVUS or OCT and ICA were uncertain across analyses. A total of 25 randomized trials (17 128 patients) were included in the pairwise meta-analyses IVI versus ICA where IVI guidance was associated with reduced target lesion revascularization, cardiac death, and stent thrombosis. CONCLUSIONS: IVI-guided PCI was associated with a reduction in ischemia-driven target lesion revascularization compared with ICA-guided PCI, with the difference most evident for IVUS. In contrast, no significant differences in myocardial infarction were observed between guidance strategies.

Invasive electrochemical impedance spectroscopy with phase delay for experimental atherosclerosis phenotyping.

Distinguishing quiescent from rupture-prone atherosclerotic lesions has significant translational and clinical implications. Electrochemical impedance spectroscopy (EIS) characterizes biological tissues by assessing impedance and phase delay responses to alternating current at multiple frequencies. We evaluated invasive 6-point stretchable EIS sensors over a spectrum of experimental atherosclerosis and compared results with intravascular ultrasound (IVUS), molecular positron emission tomography (PET) imaging, and histology. Male New Zealand White rabbits (n = 16) were placed on a high-fat diet, with or without endothelial denudation via balloon injury of the infrarenal abdominal aorta. Rabbits underwent in vivo micro-PET imaging of the abdominal aorta with 68Ga-DOTATATE, 18F-NaF, and 18F-FDG, followed by invasive interrogation via IVUS and EIS. Background signal-corrected values of impedance and phase delay were determined. Abdominal aortic samples were collected for histology. Analyses were performed blindly. EIS impedance was associated with markers of plaque activity including macrophage infiltration (r = .813, p = .008) and macrophage/smooth muscle cell (SMC) ratio (r = .813, p = .026). Moreover, EIS phase delay correlated with anatomic markers of plaque burden, namely intima/media ratio (r = .883, p = .004) and %stenosis (r = .901, p = .002), similar to IVUS. 68Ga-DOTATATE correlated with intimal macrophage infiltration (r = .861, p = .003) and macrophage/SMC ratio (r = .831, p = .021), 18F-NaF with SMC infiltration (r = -.842, p = .018), and 18F-FDG correlated with macrophage/SMC ratio (r = .787, p = .036). EIS with phase delay integrates key atherosclerosis features that otherwise require multiple complementary invasive and non-invasive imaging approaches to capture. These findings indicate the potential of invasive EIS to comprehensively evaluate human coronary artery disease.

Plasma circulating tumour DNA is a better source for diagnosis and mutational analysis of IVLBCL than tissue DNA.

Diagnosis of intravascular large B-cell lymphoma (IVLBCL) is a challenge due to its heterogeneous clinical presentation and lack of specific markers. This retrospective study investigated the utility of circulating tumour DNA (ctDNA) sequencing for diagnosing IVLBCL and analysing its mutation landscape. A cohort of 34 IVLBCL patients enrolled and underwent plasma ctDNA targeted sequencing. The median plasma ctDNA concentration was 135.0 ng/mL, significantly higher than that in diffuse large B-cell lymphoma (DLBCL) controls. Correlations were found between ctDNA concentration and disease severity indicators, LDH and SF. Mutation analysis revealed frequent mutations in B-cell receptor and NF-κB signalling pathways, including MYD88 (56%), CD79B (44%), TNFAIP3 (38%) and IRF4 (29%). CNS involvement was significantly related with BCL6 and CD58 mutation. Patients with complicated hemophagocytic lymphohistiocytosis had significantly higher mutation rates in B2M. Comparison with DLBCL subtypes showed distinctive mutation profiles in IVLBCL. Moreover, plasma ctDNA detected more mutations with higher variant allele fraction than tissue DNA, suggesting its superiority in sensitivity and accessibility. Dynamic monitoring of ctDNA during treatment correlated with therapeutic responses. This study revealed the role of ctDNA in IVLBCL diagnosis, mutation analysis, and treatment monitoring, offering a promising avenue for improving patient diagnosis in this rare lymphoma subtype.

Coagulation abnormalities associated with CAR-T-cell therapy in haematological malignancies: A review.

Chimeric antigen receptor (CAR)-T-cell therapy has demonstrated considerable efficacy and safety in the treatment of patients with relapsed/refractory haematological malignancies. Owing to significant advances, CAR-T-cell therapeutic modality has undergone substantial shifts in its clinical application. Coagulation abnormalities, which are prevalent complications in CAR-T-cell therapy, can range in severity from simple abnormalities in coagulation parameters to serious haemorrhage or disseminated intravascular coagulation associated with life-threatening multiorgan dysfunction. Nonetheless, there is a lack of a comprehensive overview concerning the coagulation abnormalities associated with CAR-T-cell therapy. With an aim to attract heightened clinical focus and to enhance the safety of CAR-T-cell therapy, this review presents the characteristics of the coagulation abnormalities associated with CAR-T-cell therapy, including clinical manifestations, coagulation parameters, pathogenesis, risk factors and their influence on treatment efficacy in patients receiving CAR-T-cell infusion. Due to limited data, these conclusions may undergo changes as more experience accumulates.

Circulating Tumor Cells: Does Ion Transport Contribute to Intravascular Survival, Adhesion, Extravasation, and Metastatic Organotropism?

Survival in the circulation, extravasation from vasculature, and colonizing new tissues represent major steps of the metastatic cascade and pose a big challenge for metastasizing tumor cells. Tumor cells circulating in blood and lymph vessels need to overcome anoikis, cope with mechanical stimuli including shear stress, and defeat attacks by the immune system. Once adhered to the vessel wall, a circulating tumor cell (CTC) can trick the endothelial cells into loosening their intercellular junctions so that the endothelium becomes penetrable for the tumor cell. Since tumor cells tend to metastasize to predestinated target organs and tissues, called organotropism, the distribution of metastases is anything but random. The molecular-physiological mechanisms underlying CTC survival, extravasation, and organotropism are very likely to include the presence and activity of ion channels/transporters due to the latter's key function in cytophysiological processes. To date, a very limited number of studies explicitly show the involvement of ion transport. This review describes the contribution of ion channels and transporters to CTC survival, extravasation, and organotropism where known and possible. In addition, supposed connections between ion transport and CTC behavior are demonstrated and imply the potential to be therapeutically taken advantage of.

Fluid-Dynamic Modeling of Flow in Embryonic Tissue Indicates That Lymphatic Valve Location Is Not Consistently Determined by the Local Fluid Shear or Its Gradient.

OBJECTIVE: Intravascular lymphatic valves often occur in proximity to vessel junctions. It is commonly held that disturbed flow at junctions is responsible for accumulation of valve-forming cells (VFCs) at these locations as the initial step in valve creation, and the one which explains the association with these sites. However, evidence in favor is largely limited to cell culture experiments. METHODS: We acquired images of embryonic lymphatic vascular networks from day E16.5, when VFC accumulation has started but the developing valve has not yet altered the local vessel geometry, stained for Prox1, which co-localizes with Foxc2. Using finite-element computational fluid mechanics, we simulated the flow through the networks, under conditions appropriate to this early development stage. Then we correlated the Prox1 distributions with the distributions of simulated fluid shear and shear stress gradient. RESULTS: Across a total of 16 image sets, no consistent correlation was found between Prox1 distribution and the local magnitude of fluid shear, or its positive or negative gradient. CONCLUSIONS: This, the first direct semi-empirical test of the localization hypothesis to interrogate the tissue from in vivo at the critical moment of development, does not support the idea that a feature of the local flow determines valve localization.

Surgical Management of Wilms Tumors with Intravenous Extension: A Multicenter Analysis of Clinical Management with Technical Insights.

BACKGROUND: About 5% of Wilms tumors present with vascular extension, which sometimes extends to the right atrium. Vascular extension does not affect the prognosis, but impacts the surgical strategy, which is complex and not fully standardized. Our goal is to identify elements of successful surgical management of Wilms tumors with vascular extensions. PATIENTS AND METHODS: A retrospective study of pediatric Wilms tumors treated at three sites (January 1999-June 2019) was conducted. The inclusion criterion was the presence of a renal vein and vena cava thrombus at diagnosis. Tumor stage, pre and postoperative treatment, preoperative imaging, operative report, pathology, operative complications, and follow-up data were reviewed. RESULTS: Of the 696 pediatric patients with Wilms tumors, 69 (9.9%) met the inclusion criterion. In total, 24 patients (37.5%) had a right atrial extension and two presented with Budd-Chiari syndrome at diagnosis. Two died at diagnosis owing to pulmonary embolism. All patients received neoadjuvant chemotherapy and thrombus regressed in 35.6% of cases. Overall, 14 patients had persistent intra-atrial thrombus extension (58%) and underwent cardiopulmonary bypass. Most thrombi (72%) were removed intact with nephrectomy. Massive intraoperative bleeding occurred during three procedures. Postoperative renal insufficiency was identified as a risk factor for patient survival (p = 0.01). With a median follow-up of 9 years (range: 0.5-20 years), overall survival was 89% and event-free survival was 78%. CONCLUSIONS: Neoadjuvant chemotherapy with proper surgical strategy resulted in a survival rate comparable to that of children with Wilms tumors without intravascular extension. Clinicians should be aware that postoperative renal insufficiency is associated with worse survival outcomes.

Stabilization of Rapidly Progressive Cardiac Allograft Vasculopathy Using mTOR Inhibition After Heart Transplantation.

BACKGROUND: Inhibition of the mammalian target of rapamycin (mTor) pathway after heart transplantation has been associated with reduced progression of coronary allograft vasculopathy (CAV). The application of low-dose mTOR inhibition in the setting of modern immunosuppression, including tacrolimus, remains an area of limited exploration. METHODS: This retrospective study included patients who received heart transplantation between January 2009 and January 2019 and had baseline, 1-year and 2-3-year coronary angiography with intravascular ultrasound (IVUS). Intimal thickness in 5 segments along the left anterior descending artery was compared across imaging time points in patients who were transitioned to low-dose mTOR inhibitor (sirolimus) vs standard treatment with mycophenolate on a background of tacrolimus. Long-term adverse cardiovascular outcomes (revascularization, severe CAV, retransplant, and cardiovascular death) were also assessed. RESULTS: Among 216 patients (mean age 51.5 ± 11.9 years, 77.8% men, 80.1% white), 81 individuals (37.5%) were switched to mTOR inhibition. mTOR inhibition was associated with a reduction in intimal thickness by 0.05 mm (95% CI 0.02-0.07; P < 0.001). This reduction was driven by patients who met the criteria for rapidly progressive CAV 1-year post-transplant (0.12 mm; P = 0.016 for interaction). After a median follow-up of 8.6 (IQR 6.6-11) years, 40 patients had major adverse cardiovascular outcomes. The use of mTOR inhibitors was not significantly associated with cardiovascular outcomes (P = 0.669). CONCLUSION: Transitioning patients after heart transplantation to an immunosuppression regimen composed of low-dose mTOR inhibition and tacrolimus was associated with a lack of progression of CAV, particularly in those with rapidly progressive CAV at 1 year, but not with long-term cardiovascular outcomes.

Congestion/decongestion in heart failure: what does it mean, how do we assess it, and what are we missing?-is there utility in measuring volume?

Clinical congestion remains a major cause of hospitalization and re-hospitalizations in patients with chronic heart failure (HF). Despite the high prevalence of this issue and clinical concern in HF practice, there is limited understanding of the complex pathophysiology relating to the "congestion" of congestive HF. There is no unifying definition or clear consensus on what is meant or implied by the term "congestion." Further, the discordance in study findings relating congestion to physical signs and symptoms of HF, cardiac hemodynamics, or metrics of weight change or fluid loss with diuretic therapy has not added clarity. In this review, these factors will be discussed to add perspective to this issue and consider the factors driving "congestion." There remains a need to better understand the roles of fluid retention promoting intravascular and interstitial compartment expansions, blood volume redistribution from venous reservoirs, altered venous structure and capacity, elevated cardiac filling pressure hemodynamics, and heterogeneous intravascular volume profiles (plasma volume and red blood cell mass) with a goal to help demystify "congestion" in HF. Further, this includes highlighting the importance of recognizing that congestion is not the result of a single pathway but a complex of responses some of which produce symptoms while others do not; yet, we confine these varied responses to the single and somewhat vague term "congestion."

Sex-specific analysis of intravascular lithotripsy for peripheral artery disease from the Disrupt PAD III observational study.

OBJECTIVE: Endovascular therapy of lower extremity peripheral artery disease (PAD) is associated with higher complication rates and worse outcomes in women vs men. Although intravascular lithotripsy (IVL) has shown similarly favorable outcomes in men and women in calcified coronary arteries, there is no published safety and effectiveness data of peripheral IVL differentiated by sex. This study aims to evaluate sex-specific acute procedural safety and effectiveness following IVL treatment of calcified PAD. METHODS: We performed a secondary analysis of the multicenter Disrupt PAD III Observational Study, which assessed short-term procedural outcomes of patients undergoing treatment of symptomatic calcified lower extremity PAD with the Shockwave peripheral IVL system. Adjudicated acute safety and efficacy outcomes were compared by sex using univariate analysis performed with the χ2 test or Fisher exact test, as appropriate. RESULTS: A total of 1262 patients (29.9% women) were included, with >85% having moderate to severe lesion calcification. Women were older (74 vs 71 years; P < .001), had lower ankle-brachial index (0.7 vs 0.8; P = .003), smaller reference vessel size (5.3 vs 5.6 mm; P = .009), and more severe stenosis at baseline vs men (82.3% vs 79.8%; P = .012). Rates of diabetes, renal insufficiency, chronic limb-threatening ischemia, lesion length, and atherectomy use were similar in both groups. Residual stenosis after IVL alone was significantly reduced in both groups. Final residual stenosis was 21.9% in women and 24.7% in men (P = .001). Serious angiographic complications were infrequent and similar in both groups (1.4% vs 0.6%; P = .21), with no abrupt vessel closure, distal embolization, or thrombotic events during any procedure. CONCLUSIONS: The use of IVL to treat calcified PAD in this observational registry demonstrated favorable acute safety and effectiveness in both women and men.

The mid-term effect of intravascular ultrasound on endovascular interventions for lower extremity peripheral arterial disease: A systematic review and meta-analysis.

OBJECTIVE: Intravascular ultrasound (IVUS) is an important adjunctive tool for patients with lower extremity peripheral arterial disease (PAD) undergoing endovascular therapy (EVT). The evidence regarding the advantages of IVUS use is evolving, and recent studies have reported conflicting results. We aimed to perform a meta-analysis to evaluate the efficacy of IVUS during angiography-guided EVT for patients with PAD. METHODS: MEDLINE and EMBASE were searched through April 2023 to identify studies that investigated the outcomes of IVUS with angiography-guided EVT vs angiography-alone-guided EVT. The primary outcome was restenosis/occlusion rate; secondary outcomes were target lesion revascularization, major amputation, and mortality. RESULTS: One randomized controlled trial and 14 observational studies, largely of moderate quality, were included, yielding a total of 708,808 patients with 709,189 lesions that were treated with IVUS-guided EVT (n = 101,405) vs angiography-alone (n = 607,784). Compared with angiography alone, IVUS-guided EVT was associated with a non-significant trend towards decreased restenosis/occlusion (relative risk [RR], 0.74; 95% confidence interval [CI], 0.54-1.00; I2 = 60%). Although the risk of target lesion revascularization and mortality were comparable (RR, 0.85; 95% CI, 0.65-1.10; I2 = 70%; RR, 1.01; 95% CI, 0.79-1.28; I2 = 43%, respectively), the use of IVUS was also associated with significantly lower risk of major amputation (RR, 0.74; 95% CI, 0.67-0.82; I2 = 47%). Subgroup analysis focusing on femoropopliteal disease demonstrated significantly higher patency (RR, 0.72; 95% CI, 0.52-0.98; I2 = 73%). However, superiority with major amputation was not observed. CONCLUSIONS: IVUS-guided EVT for PAD may possibly be associated with a lower major amputation rate compared with angiography alone-guided EVT, although the difference in patency remained an insignificant trend in favor of IVUS-guided EVT. Adjunctive use of IVUS during EVT may be beneficial, and further prospective studies are warranted to delineate this relationship and the applicability of this technology in routine practice.

Role of intravascular ultrasound for the technical assessment of endovascular reconstruction of the aortic bifurcation.

OBJECTIVE: The aim of this study was to evaluate the role of intravascular ultrasound (IVUS) for the technical assessment of kissing stents (KSs) and covered endovascular reconstruction of the aortic bifurcation (CERAB) in the treatment of aortoiliac obstructive disease involving the aortic bifurcation. METHODS: We conducted a single-center retrospective review of patients undergoing endovascular treatment of severe aorto-iliac obstructive disease (2019-2023). IVUS was performed in patients treated by KSs or CERAB according to preoperative indications, in cases of moderate/severe calcifications, mural thrombus, total occlusions, and lesion extension towards the proximity of renal or hypogastric arteries. Indications for IVUS-guided intraoperative revisions were residual stenosis or compression >30%, incomplete stent-to-wall apposition, or flow-limiting dissection at the landing site. Follow-up assessment was performed at 6 and 12 months, and then yearly. Thirty-day outcomes and 2-year patency rates were evaluated. Logistic regression was used to identify factors associated with significant technical defects detected by IVUS needing intraoperative revision. RESULTS: IVUS was used for the technical assessment of 102 patients treated by KSs (n = 57; 56%) or CERAB (n = 45; 44%) presenting with severe intermittent claudication (39%), rest pain (39%), or ischemic tissue loss (25%). Twenty-nine significant technical defects were identified by IVUS in 25 patients (25%) who then had successful intraoperative correction by additional ballooning (n = 23; 80%) or stenting (n = 6; 20%). Patients with a severely calcified chronic total occlusion (odds ratio, 1.85; 95% confidence interval, 1.01-5.27; P = .044) or severely calcified narrow aortic bifurcation with <12 mm diameter (odds ratio, 2.34; 95% confidence interval, 1.10-8.64; P = .032) were at increased risk for IVUS-guided intraoperative revision. There were no postoperative deaths and no major adverse events. Two-year primary patency was 100%. CONCLUSIONS: IVUS was used for the technical assessment of KSs/CERAB in a selected cohort of patients with severe aorto-iliac obstructive disease. This allowed the identification and intraoperative correction of a significant technical defect not detected by completion angiogram in one-quarter of patients, achieving optimal 2-year results. IVUS assessment of KSs/CERAB may be considered especially in patients with a calcified total occlusion or narrow aortic bifurcation.

Calcified Nodules in Non-Culprit Lesions with Acute Coronary Syndrome Patients.

Background: Calcified nodules (CN) have been linked to unfavorable clinical outcomes. However, there is a lack of systematic studies on non-culprit lesions with CN in patients with acute coronary syndromes (ACS). This study aims to investigate the frequency, distribution, predictors, and outcomes of CN in non-culprit lesions among ACS patients. Methods: We included 376 ACS patients who received successful stent placement in their culprit lesions. Intravascular ultrasound (IVUS) was performed to evaluate non-culprit lesions in left main arteries and all three coronary arteries (CA). CN was defined as accumulations of small nodular calcium deposits exhibiting a convex shape protruding into the lumen. Results: CNs was identified in 16.9% (121 of 712) per artery and 26.9% (101 of 376) per patient. They were predominantly located at the mid portion of the right coronary artery (26.3%) and the bifurcation site (59.9%). Patients with CN were older (63.57 ± 8.43 vs. 57.98 ± 7.15, p < 0.001) and had a higher prevalence of diabetes mellitus (55.4% vs. 42.2%, p = 0.022). However, there were no significant differences in baseline characteristics observed after propensity score matching (PSM). Multivariate analysis revealed that CN were independently associated with major adverse cardiovascular events (MACE) both before and after PSM (hazard ratio (HR): 0.341, 95% confidence interval (95% CI): 0.140-0.829, p = 0.018; HR: 0.275, 95% CI: 0.108-0.703, p = 0.007, respectively). During the observational period of 19.35 ± 10.59 months, the occurrence of MACE was significantly lower in patients with CN before and after PSM (5.9% vs. 16.7%, p = 0.046; 4.0% vs. 18.1%, p = 0.011; respectively). Conclusions: CN in non-culprit lesions with ACS patients was prevalent and caused fewer adverse clinical outcomes.

Volumetric Stent Expansion Index to Assess Tapering Lesions Using Intravascular Ultrasound and Its Clinical Outcomes.

Background: This study aimed to assess the clinical significance of generating a volumetric stent expansion index for tapering lesions through intravascular ultrasound (IVUS). Previous IVUS studies have used minimal stent area (MSA) to predict adverse outcomes. Methods: A total of 251 tapering lesions were treated in this study via IVUS guidance in 232 patients. Eight stent expansion indices were evaluated to determine the association of these indices with device-oriented clinical endpoints (DoCEs) after two-year follow-ups. These were the ILUMIEN III and IV standards, the ULTIMATE (Intravascular Ultrasound Guided Drug Eluting Stents Implantation in "All-Comers" Coronary Lesions) standard, the IVUS-XPL (Impact of Intravascular Ultrasound Guidance on the Outcomes of Xience Prime Stents in Long Lesions) standard, the minimal volumetric expansion index (MVEI) using the Huo-Kassab or linear model, the MSA/vessel area at the MSA cross-section, the traditional stent expansion (MSA/mean proximal and distal reference lumen cross-sectional area), and MSA. Results: The MVEI was the only stent expansion index that correlated significantly with the two-year DoCEs (hazard ratio [HR], 1.91; 95% confidence interval [CI]: 1.16-3.96; p = 0.028). In the ROC analysis, the area under the curve for the MVEI was 0.71 (p = 0.002), with an optimal cut-off value of 62.2 for predicting the DoCEs. Conclusions: This is the first study to use IVUS for tapering lesions and demonstrate that the MVEI is an independent predictor of two-year DoCEs.

Clinical Implications of Acute Stent Mal-Apposition in the Left Main Coronary Artery.

Background: Intravascular ultrasound (IVUS) has been utilized to determine acute stent mal-apposition (ASM) after percutaneous coronary intervention (PCI) in the left main coronary artery (LMCA). However, the clinical consequences of this finding remain uncertain. This research aimed to evaluate the clinical implications of ASM in the LMCA using IVUS. Methods: In this study, 408 patients who underwent successful drug-eluting stent (DES) implantation in the LMCA were evaluated. We analyzed the prevalence and characteristics of ASM and its correlation with clinical outcomes. ASM is characterized by stent struts that are not in immediate proximity to the intimal surface of the vessel wall after initial stent deployment. Results: The observed incidence of LMCA-ASM post-successful PCI was 26.2%, both per patient and per lesion. Lesions with LMCA-ASM had a longer stent diameter, larger stent areas, and larger lumen areas compared to those without LMCA-ASM (4.0 ± 0.5 vs. 3.7 ± 0.4 mm, p < 0.001; 9.8 ± 2.0 vs. 9.0 ± 1.6 mm 2 , p < 0.001; 12.3 ± 1.9 vs. 10.1 ± 2.1 mm 2 , p < 0.001, respectively). The mean external elastic membrane (EEM) area (odds ratio (OR): 1.418 [95% confidence interval (CI): 1.295-1.556]; p < 0.001) emerged as an independent predictor of LMCA-ASM. During the observation period, LMCA-ASM did not display any association with device-oriented clinical endpoints (DoCE), which included cardiac death, target vessel-induced myocardial infarction (MI), stent thrombosis, and target lesion revascularization (TLR). Moreover, the DoCE incidence exhibited no significant disparity between patients with or without ASM (13.1 vs. 6.0%, p = 0.103). Conclusions: While LMCA-ASM was a not uncommon finding post-PCI, it did not correlate with adverse cardiac events in the present study.