Deploying a novel custom mobile application for STEMI activation and transfer in a large healthcare system to improve cross-team workflow. STEMIcathAID implementation project.

BACKGROUND: ST-segment elevation myocardial infarction (STEMI) is a high-risk patient medical emergency. We developed a secure mobile application, STEMIcathAID, to optimize care for STEMI patients by providing a digital platform for communication between the STEMI care team members, EKG transmission, cardiac catherization laboratory (cath lab) activation and ambulance tracking. The aim of this report is to describe the implementation of the app into the current STEMI workflow in preparation for a pilot project employing the app for inter-hospital STEMI transfer. APPROACH: App deployment involved key leadership stakeholders from all multidisciplinary teams taking care of STEMI patients. The team developed a transition plan addressing all aspects of the health system improvement process including the workflow analysis and redesign, app installation, personnel training including user account access to the app, and development of a quality assurance program for progress evaluation. The pilot will go live in the Emergency Department (ED) of one of the hospitals within the Mount Sinai Hospital System (MSHS) during the daytime weekday hours at the beginning and extending to 24/7 schedule over 4-6 weeks. For the duration of the pilot, ED personnel will combine the STEMIcathAID app activation with previous established STEMI activation processes through the MSHS Clinical Command Center (CCC) to ensure efficient and reliable response to a STEMI alert. More than 250 people were provisioned app accounts including ED Physicians and frontline nurses, and trained on their user-specific roles and responsibilities and scheduled in the app. The team will be provided with a feedback form that is discipline specific to complete after every STEMI case in order to collect information on user experience with the STEMIcathAID app functionality. The form will also provide quantitative metrics for the key time sensitive steps in STEMI care. CONCLUSIONS: We developed a uniform approach for deployment of a mobile application for STEMI activation and transfer in a large urban healthcare system to optimize the clinical workflow in STEMI care. The results of the pilot will demonstrate whether the app has a significant impact on the quality of care for transfer of STEMI patients.

Rationale and design of a randomized trial evaluating an external support device for saphenous vein coronary grafts.

BACKGROUND: Coronary artery bypass grafting (CABG) is the most common revascularization approach for the treatment of multi-vessel coronary artery disease. While the internal mammary artery is nearly universally used to bypass the left anterior descending coronary artery, autologous saphenous vein grafts (SVGs) are still the most frequently used conduits to grafts the remaining coronary artery targets. Long-term failure of these grafts, however, continues to limit the benefits of surgery. METHODS: The Cardiothoracic Surgical Trials Network trial of the safety and effectiveness of a Venous External Support (VEST) device is a randomized, multicenter, within-patient trial comparing VEST-supported versus unsupported saphenous vein grafts in patients undergoing CABG. Key inclusion criteria are the need for CABG with a planned internal mammary artery to the left anterior descending and two or more saphenous vein grafts to other coronary arteries. The primary efficacy endpoint of the trial is SVG intimal hyperplasia (plaque + media) area assessed by intravascular ultrasound at 12 months post randomization. Occluded grafts are accounted for in the analysis of the primary endpoint. Secondary confirmatory endpoints are lumen diameter uniformity and graft failure (>50% stenosis) assessed by coronary angiography at 12 months. The safety endpoints are the occurrence of major adverse cardiac and cerebrovascular events and hospitalization within 5 years from randomization. CONCLUSIONS: The results of the VEST trial will determine whether the VEST device can safely limit SVG intimal hyperplasia in patients undergoing CABG as treatment for coronary atherosclerotic disease.

Management of calcified coronary artery bifurcation lesions.

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.

Procedural and 1-year clinical outcomes of orbital atherectomy for treatment of coronary in-stent restenosis: A single-center, retrospective study.

OBJECTIVES: We evaluated the procedural and 1-year clinical outcomes of orbital atherectomy (OA) for treatment of coronary in-stent restenosis (ISR). BACKGROUND: The optimal treatment for ISR remains uncertain. While rotational and laser atherectomy have been used as neointimal debulking techniques for ISR, there have been few reports on OA for ISR. METHODS: This is a retrospective observational study of consecutive patients who underwent percutaneous coronary intervention (PCI) for ISR with OA in Mount Sinai catheterization laboratory between November 2013 and January 2018. Procedural success was defined as angiographic success without in-hospital major adverse cardiac events (MACE; the composite of all-cause death, myocardial infarction [MI], or target vessel revascularization). Clinical outcomes were assessed at 1 month and 12 months postprocedure. RESULTS: A total of 87 patients were included in the study. All 87 patients were treated with OA, after which 49 (56.3%) patients also received new drug-eluting stents. Angiographic success was achieved in 87 (100%) patients and procedural success was achieved in 79 (90.8%) patients. In-hospital MACE occurred in 8 (9.2%) patients, all due to periprocedural non-Q-wave MI. Acute lumen gain was 1.19 ± 0.57 mm after OA plus balloon angioplasty and 1.75 ± 0.50 mm after stent placement. MACE within 1 year occurred in 17 (19.5%) patients. CONCLUSIONS: OA for ISR was performed with favorable procedural and 1-year clinical outcomes. Randomized trials are warranted to determine whether OA improves the poor prognosis of patients with ISR treated without debulking.

Side branch fractional flow reserve after provisional stenting of calcified bifurcation lesions: The ORBID-FFR study.

OBJECTIVES: We examined the incidence of side branch (SB) compromise after provisional stenting of calcified bifurcation lesions treated with rotational atherectomy (RA) or cutting balloon angioplasty (CBA) and the utility of optical coherence tomography (OCT) to detect functionally significant SB stenoses. BACKGROUND: The comparative impact of RA versus CBA on SB compromise and functional significance remains poorly characterized. METHODS: Seventy-one consecutive patients with 71 calcified bifurcation lesions with angiographically intermediate SB stenoses were randomized to RA (n = 35) or CBA (n = 36). The primary endpoint was SB compromise defined as SB diameter stenosis ≥70%, SB dissection or thrombolysis in myocardial infarction flow grade < 3 after provisional stenting. Secondary endpoints included SB FFR in noncompromised SBs and its correlation with SB ostium area (SBOA) assessed by three-dimensional OCT. RESULTS: SB compromise after provisional stenting was observed in 7 (20.0%) lesions that underwent RA and in 9 (25.0%) lesions treated with CBA (p = .62). Mean SB FFR was 0.83 ± 0.08 and was similar between the study arms. Functionally significant SB stenosis (FFR ≤ 0.80) was detected in 17(30.9%) angiographically noncompromised SBs. SBOA after stenting was an independent predictor of FFR ≤ 0.80 (OR 0.002, 95% CI: 0.00-0.15, p = .002). The optimal cutoff value for SBOA to predict functionally significant SB stenosis was 0.76 mm2 (sensitivity 82%, specificity 89% and area under the curve 0.92, 95% CI: 0.84-0.99). CONCLUSIONS: The rates of SB compromise and functionally significant stenosis after provisional stenting of calcified bifurcation lesions were similar between two lesion preparation strategies. OCT SBOA can detect SB branches with FFR ≤ 0.80 with high sensitivity and specificity.

Cardiovascular outcomes after percutaneous coronary intervention on bifurcation lesions with moderate to severe coronary calcium: A single-center registry study.

BACKGROUND: Both target vessel calcification and target vessel bifurcation are associated with worse outcomes following percutaneous coronary intervention (PCI). Whether these entities in combination interact to influence outcomes after PCI of complex coronary disease is not known. OBJECTIVES: This study evaluated the association of target vessel bifurcation and target vessel calcification, alone and in combination, with adverse events following PCI. METHODS: Registry data from 21,165 patients who underwent PCI with drug-eluting stents (DES) between January 2009 and December 2017 were analyzed. Patients were divided into four groups according to the presence or absence of target vessel bifurcation and presence of none/mild or moderate/severe target vessel calcification on angiography. Associations between lesion groups and 1 year major adverse cardiac events (MACE) were examined using Cox regression analysis. RESULTS: At 1 year, unadjusted rates of MACE, death, myocardial infarction (MI), as well as stent thrombosis were highest in the group with both bifurcation lesion and moderate/severe calcification. After adjusting for confounders such as age, renal disease, and smoking, hazard ratios for MACE were 1.14 (95%CI 0.99-1.33) for bifurcation with none/mild calcification, 1.21 (95%CI 1.06-1.38) for no bifurcation and moderate/severe calcification, and 1.37 (95%CI 1.14-1.64) for bifurcation and moderate severe calcification, compared to patients with no bifurcation and none/mild calcification. CONCLUSIONS: The presence of a bifurcating target vessel with moderate/severe calcification is associated with a higher risk of adverse outcomes than either attribute alone. New approaches are needed to improve outcomes in this subset of patients with complex coronary artery disease.

Predictors of side branch compromise in calcified bifurcation lesions treated with orbital atherectomy.

OBJECTIVES: The aim of the study was to identify the predictors of side branch (SB) compromise in severely calcified bifurcation lesions treated with orbital atherectomy (OA). BACKGROUND: SB compromise remains a major complication of bifurcation lesion percutaneous coronary intervention (PCI). Higher prevalence of lipid-rich plaques and spotty calcification by optical coherence tomography (OCT) and SB ostial stenosis by angiography have been previously suggested as predictors of SB occlusion after main vessel (MV) stenting. METHODS: Patients with chronic stable angina and severely calcified bifurcation lesions, in whom provisional stenting strategy was planned, were enrolled in the study. OA was used for lesion preparation in all cases. OCT imaging of the MV was performed before and after stenting. SB compromise was defined as a composite of SB occlusion (TIMI flow grade ≤ 2) and SB intervention after MV stenting. RESULTS: Thirty stable CAD patients with 30 severely calcified bifurcation lesions were included in the study. Twelve patients (40%) had a compromised SB after MV stenting. Compromised SB was characterized by a greater angiographic diameter stenosis (55.4 ± 8.1% vs. 35.0 ± 14.4%, P < 0.01) and a smaller minimal lumen diameters (0.79 ± 0.17 vs. 1.12 ± 0.30 mm, P = 0.002) before PCI compared to noncompromised SB. The prevalence of OCT lipid-rich plaques was low and did not differ between the groups (18 vs. 19%, P = 0.68). There was no difference in other OCT plaque characteristics including the presence of spotty calcification. CONCLUSION: The severity of SB ostial disease and not MV plaque morphology contributed to SB compromise in severely calcified bifurcation lesions.

Plaque morphology predictors of side branch occlusion after provisional stenting in coronary bifurcation lesion: Results of optical coherence tomography bifurcation study (ORBID).

OBJECTIVES: The aim of this study was to identify the predictors of side branch (SB) ostial stenosis developed after provisional stenting of the main vessel (MV) using optical coherence tomography (OCT). BACKGROUND: Provisional stenting remains the main approach to treatment of bifurcation lesions; however, it may result in the narrowing of SB ostium. There is little information about underlying plaque morphology of the MV lesion and its potential impact on the SB after provisional stenting. METHODS: Patients with stable coronary disease with angiographic MV lesion not involving SB were included in a prospective single center study. The primary outcome was significant SB ostium stenosis (SBOS), defined as residual stenosis of >50% after MV stenting. RESULTS: Thirty bifurcation lesions in 30 patients were analyzed in the study. Poststenting significant SBOS was observed in 30% of patients. The MV lesions with SBOS > 50% were characterized by a higher prevalence of lipid rich plaques (100 vs. 64%, p = 0.040) and spotty calcifications (60 vs. 0%, p = 0.005). Maximal lipid arcs were greater (257° vs. 132°, p = 0.001) and lipid volume index was higher (1380 vs. 574, p = 0.012) in the SBOS >50% group. Multivariate logistic regression analysis identified maximal lipid arc (odds ratio (OR): 1.014, p = 0.038) and the presence of lipid plaque contralateral to SB ostium (OR: 8.14, p = 0.046) before stenting as independent predictors of significant SBOS after PCI. CONCLUSIONS: High lipid content of the MV lesion and a contralateral location of lipid in the bifurcation area may contribute to SBOS after provisional stenting. © 2016 Wiley Periodicals, Inc.

Epigenome-guided analysis of the transcriptome of plaque macrophages during atherosclerosis regression reveals activation of the Wnt signaling pathway.

We report the first systems biology investigation of regulators controlling arterial plaque macrophage transcriptional changes in response to lipid lowering in vivo in two distinct mouse models of atherosclerosis regression. Transcriptome measurements from plaque macrophages from the Reversa mouse were integrated with measurements from an aortic transplant-based mouse model of plaque regression. Functional relevance of the genes detected as differentially expressed in plaque macrophages in response to lipid lowering in vivo was assessed through analysis of gene functional annotations, overlap with in vitro foam cell studies, and overlap of associated eQTLs with human atherosclerosis/CAD risk SNPs. To identify transcription factors that control plaque macrophage responses to lipid lowering in vivo, we used an integrative strategy--leveraging macrophage epigenomic measurements--to detect enrichment of transcription factor binding sites upstream of genes that are differentially expressed in plaque macrophages during regression. The integrated analysis uncovered eight transcription factor binding site elements that were statistically overrepresented within the 5' regulatory regions of genes that were upregulated in plaque macrophages in the Reversa model under maximal regression conditions and within the 5' regulatory regions of genes that were upregulated in the aortic transplant model during regression. Of these, the TCF/LEF binding site was present in promoters of upregulated genes related to cell motility, suggesting that the canonical Wnt signaling pathway may be activated in plaque macrophages during regression. We validated this network-based prediction by demonstrating that ß-catenin expression is higher in regressing (vs. control group) plaques in both regression models, and we further demonstrated that stimulation of canonical Wnt signaling increases macrophage migration in vitro. These results suggest involvement of canonical Wnt signaling in macrophage emigration from the plaque during lipid lowering-induced regression, and they illustrate the discovery potential of an epigenome-guided, systems approach to understanding atherosclerosis regression.

Cholesterol loading reprograms the microRNA-143/145-myocardin axis to convert aortic smooth muscle cells to a dysfunctional macrophage-like phenotype.

OBJECTIVE: We previously showed that cholesterol loading in vitro converts mouse aortic vascular smooth muscle cells (VSMC) from a contractile state to one resembling macrophages. In human and mouse atherosclerotic plaques, it has become appreciated that ≈40% of cells classified as macrophages by histological markers may be of VSMC origin. Therefore, we sought to gain insight into the molecular regulation of this clinically relevant process. APPROACH AND RESULTS: VSMC of mouse (or human) origin were incubated with cyclodextrin-cholesterol complexes for 72 hours, at which time the expression at the protein and mRNA levels of contractile-related proteins was reduced and of macrophage markers increased. Concurrent was downregulation of miR-143/145, which positively regulate the master VSMC differentiation transcription factor myocardin. Mechanisms were further probed in mouse VSMC. Maintaining the expression of myocardin or miR-143/145 prevented and reversed phenotypic changes caused by cholesterol loading. Reversal was also seen when cholesterol efflux was stimulated after loading. Notably, despite expression of macrophage markers, bioinformatic analyses showed that cholesterol-loaded cells remained closer to the VSMC state, consistent with impairment in classical macrophage functions of phagocytosis and efferocytosis. In apoE-deficient atherosclerotic plaques, cells positive for VSMC and macrophage markers were found lining the cholesterol-rich necrotic core. CONCLUSIONS: Cholesterol loading of VSMC converts them to a macrophage-appearing state by downregulating the miR-143/145-myocardin axis. Although these cells would be classified by immunohistochemistry as macrophages in human and mouse plaques, their transcriptome and functional properties imply that their contributions to atherogenesis would not be those of classical macrophages.

Optical coherence tomography assessment of the mechanistic effects of rotational and orbital atherectomy in severely calcified coronary lesions.

OBJECTIVES: This study sought to assess the mechanistic effect of rotational atherectomy (RA) and orbital atherectomy (OA) on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). BACKGROUND: RA and OA are two main approaches to ablate coronary calcium. While small case reports have described the mechanistic effect of RA in calcified coronary lesions, there has been no imaging study to assess the effect of OA on coronary artery architecture and/or compare the effects of two atherectomy devices. METHODS: This study analyzed 20 consecutive patients with OCT imaging performed after atherectomy and after stent implantation, RA (n = 10) and OA (n = 10). RESULTS: Postatherectomy OCT analysis identified tissue modification with deep dissections in around a third of lesions after RA and OA; however, post OA dissections ("lacunae") were significantly deeper (1.14 vs. 0.82 mm, P = 0.048). Post OA/RA lesions with dissections had significantly higher percentage of lipid rich plaques and smaller calcification arcs as compared to plaques without dissections. Stents after OA were associated with a significantly lower percent of stent strut malapposition than post RA stents (4.36 vs. 8.02%, P = 0.038). CONCLUSIONS: Although the incidence of dissections was comparable between RA and OA cases, OA resulted in deeper tissue modifications (lacunae) as shown by OCT imaging. The finding might provide an explanation for a better stent apposition after OA as compared to RA. Their impact on long-term outcome needs to be determined.

Deficiency of ATP-binding cassette transporters A1 and G1 in macrophages increases inflammation and accelerates atherosclerosis in mice.

RATIONALE: Plasma high-density lipoprotein levels are inversely correlated with atherosclerosis. Although it is widely assumed that this is attributable to the ability of high-density lipoprotein to promote cholesterol efflux from macrophage foam cells, direct experimental support for this hypothesis is lacking. OBJECTIVE: To assess the role of macrophage cholesterol efflux pathways in atherogenesis. METHODS AND RESULTS: We developed mice with efficient deletion of the ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1) in macrophages (MAC-ABC(DKO) mice) but not in hematopoietic stem or progenitor populations. MAC-ABC(DKO) bone marrow (BM) was transplanted into Ldlr(-/-) recipients. On the chow diet, these mice had similar plasma cholesterol and blood monocyte levels but increased atherosclerosis compared with controls. On the Western-type diet, MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice had disproportionate atherosclerosis, considering they also had lower very low-density lipoprotein/low-density lipoprotein cholesterol levels than controls. ABCA1/G1-deficient macrophages in lesions showed increased inflammatory gene expression. Unexpectedly, Western-type diet-fed MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice displayed monocytosis and neutrophilia in the absence of hematopoietic stem and multipotential progenitor cells proliferation. Mechanistic studies revealed increased expressions of machrophage colony stimulating factor and granulocyte colony stimulating factor in splenic macrophage foam cells, driving BM monocyte and neutrophil production. CONCLUSIONS: These studies show that macrophage deficiency of ABCA1/G1 is proatherogenic likely by promoting plaque inflammation and uncover a novel positive feedback loop in which cholesterol-laden splenic macrophages signal BM progenitors to produce monocytes, with suppression by macrophage cholesterol efflux pathways.

HDL promotes rapid atherosclerosis regression in mice and alters inflammatory properties of plaque monocyte-derived cells.

HDL cholesterol (HDL-C) plasma levels are inversely related to cardiovascular disease risk. Previous studies have shown in animals and humans that HDL promotes regression of atherosclerosis. We hypothesized that this was related to an ability to promote the loss of monocyte-derived cells (CD68(+), primarily macrophages and macrophage foam cells) from plaques. To test this hypothesis, we used an established model of atherosclerosis regression in which plaque-bearing aortic arches from apolipoprotein E-deficient (apoE(-/-)) mice (low HDL-C, high non-HDL-C) were transplanted into recipient mice with differing levels of HDL-C and non-HDL-C: C57BL6 mice (normal HDL-C, low non-HDL-C), apoAI(-/-) mice (low HDL-C, low non-HDL-C), or apoE(-/-) mice transgenic for human apoAI (hAI/apoE(-/-); normal HDL-C, high non-HDL-C). Remarkably, despite persistent elevated non-HDL-C in hAI/apoE(-/-) recipients, plaque CD68(+) cell content decreased by >50% by 1 wk after transplantation, whereas there was little change in apoAI(-/-) recipient mice despite hypolipidemia. The decreased content of plaque CD68(+) cells after HDL-C normalization was associated with their emigration and induction of their chemokine receptor CCR7. Furthermore, in CD68(+) cells laser-captured from the plaques, normalization of HDL-C led to decreased expression of inflammatory factors and enrichment of markers of the M2 (tissue repair) macrophage state. Again, none of these beneficial changes were observed in the apoAI(-/-) recipients, suggesting a major requirement for reverse cholesterol transport for the beneficial effects of HDL. Overall, these results establish HDL as a regulator in vivo of the migratory and inflammatory properties of monocyte-derived cells in mouse atherosclerotic plaques, and highlight the phenotypic plasticity of these cells.

Rotational atherectomy combined with cutting balloon to optimise stent expansion in calcified lesions: the ROTA-CUT randomised trial.

BACKGROUND: Percutaneous coronary intervention (PCI) of calcified lesions remains challenging for interventionalists. AIMS: We aimed to investigate whether combining rotational atherectomy (RA) with cutting balloon angioplasty (RA+CBA) results in more optimal stent expansion compared with RA followed by non-compliant balloon angioplasty (RA+NCBA). METHODS: ROTA-CUT is a prospective, multicentre, randomised trial of 60 patients with coronary artery disease undergoing PCI of moderately or severely calcified lesions with drug-eluting stent implantation. Patients were randomised 1:1 to either RA+CBA or RA+NCBA. The primary endpoint was the minimum stent area on intravascular ultrasound (IVUS). Secondary endpoints included minimum lumen area and stent expansion assessed by IVUS and acute lumen gain, final residual diameter stenosis and minimum lumen diameter assessed by angiography. Clinical endpoints were obtained at 30 days. RESULTS: The mean age was 71.1±9.4 years, and 22% were women. The procedural details of RA were similar between groups, as were procedure duration and contrast use. Minimum stent area was similar with RA+CBA versus RA+NCBA (6.7±1.7 mm2 vs 6.9±1.8 mm2; p=0.685). Furthermore, there were no significant differences regarding the other IVUS and angiographic endpoints. Procedural complications were rare, and 30-day clinical events included 2 myocardial infarctions and 1 target vessel revascularisation in the RA+CBA group and 1 myocardial infarction in the RA+NCBA group. CONCLUSIONS: Combining RA with CBA resulted in a similar minimum stent area compared with RA followed by NCBA in patients undergoing PCI of moderately or severely calcified lesions. RA followed by CBA was safe with rare procedural complications and few clinical adverse events at 30 days.

LXRα regulates macrophage arginase 1 through PU.1 and interferon regulatory factor 8.

RATIONALE: Activation of liver X receptors (LXRs) inhibits the progression of atherosclerosis and promotes regression of existing lesions. In addition, LXRα levels are high in regressive plaques. Macrophage arginase 1 (Arg1) expression is inversely correlated with atherosclerosis progression and is markedly decreased in foam cells within the lesion. OBJECTIVE: To investigate LXRα regulation of Arg1 expression in cultured macrophages and atherosclerotic regressive lesions. METHODS AND RESULTS: We found that Arg1 expression is enhanced in CD68+ cells from regressive versus progressive lesions in a murine aortic arch transplant model. In cultured macrophages, ligand-activated LXRα markedly enhances basal and interleukin-4-induced Arg1 mRNA and protein expression as well as promoter activity. This LXRα-enhanced Arg1 expression correlates with a reduction in nitric oxide levels. Moreover, Arg1 expression within regressive atherosclerotic plaques is LXRα-dependent, as enhanced expression of Arg1 in regressive lesions is impaired in LXRα-deficient CD68+ cells. LXRα does not bind to the Arg1 promoter but instead promotes the interaction between PU.1 and interferon regulatory factor (IRF)8 transcription factors and induces their binding of a novel composite element. Accordingly, knockdown of either IRF8 or PU.1 strongly impairs LXRα regulation of Arg1 expression in macrophage cells. Finally, we demonstrate that LXRα binds the IRF8 locus and its activation increases IRF8 mRNA and protein levels in these cells. CONCLUSIONS: This work implicates Arg1 in atherosclerosis regression and identifies LXRα as a novel regulator of Arg1 and IRF8 in macrophages. Furthermore, it provides a unique molecular mechanism by which LXRα regulates macrophage target gene expression through PU.1 and IRF8.

Reversal of hyperlipidemia with a genetic switch favorably affects the content and inflammatory state of macrophages in atherosclerotic plaques.

BACKGROUND: We previously showed that the progression of atherosclerosis in the Reversa mouse (Ldlr(-/-Apob100/100Mttpfl/fl) Mx1Cre(+/+)) was arrested when the hyperlipidemia was normalized by inactivating the gene for microsomal triglyceride transfer protein. Here, we tested whether atherosclerosis would regress if the lipid levels were reduced after advanced plaques formed. METHODS AND RESULTS: Reversa mice were fed an atherogenic diet for 16 weeks. Plasma lipid levels were then reduced. Within 2 weeks, this reduction led to decreased monocyte-derived (CD68(+)) cells in atherosclerotic plaques and was associated with emigration of these cells out of plaques. In addition, the fall in lipid levels was accompanied by lower plaque lipid content and by reduced expression in plaque CD68(+) cells of inflammatory genes and higher expression of genes for markers of antiinflammatory M2 macrophages. Plaque composition was affected more than plaque size, with the decreased content of lipid and CD68(+) cells balanced by a higher content of collagen. When the reduced lipid level was combined with the administration of pioglitazone to simulate the clinical aggressive lipid management and proliferator-activated receptor-γ agonist treatment, the rate of depletion of plaque CD68(+) cells was unaffected, but there was a further increase in their expression of antiinflammatory macrophage markers. CONCLUSION: The Reversa mouse is a new model of atherosclerosis regression. After lipid lowering, favorable changes in plaque composition were independent of changes in size. In addition, plaque CD68(+) cells became less inflammatory, an effect enhanced by treatment with pioglitazone.

A mechanistic analysis of the role of microcalcifications in atherosclerotic plaque stability: potential implications for plaque rupture.

The role of microcalcifications (µCalcs) in the biomechanics of vulnerable plaque rupture is examined. Our laboratory previously proposed (Ref. 44), using a very limited tissue sample, that µCalcs embedded in the fibrous cap proper could significantly increase cap instability. This study has been greatly expanded. Ninety-two human coronary arteries containing 62 fibroatheroma were examined using high-resolution microcomputed tomography at 6.7-µm resolution and undecalcified histology with special emphasis on calcified particles <50 µm in diameter. Our results reveal the presence of thousands of µCalcs, the vast majority in lipid pools where they are not dangerous. However, 81 µCalcs were also observed in the fibrous caps of nine of the fibroatheroma. All 81 of these µCalcs were analyzed using three-dimensional finite-element analysis, and the results were used to develop important new clinical criteria for cap stability. These criteria include variation of the Young's modulus of the µCalc and surrounding tissue, µCalc size, and clustering. We found that local tissue stress could be increased fivefold when µCalcs were closely spaced, and the peak circumferential stress in the thinnest nonruptured cap (66 µm) if no µCalcs were present was only 107 kPa, far less than the proposed minimum rupture threshold of 300 kPa. These results and histology suggest that there are numerous µCalcs < 15 µm in the caps, not visible at 6.7-µm resolution, and that our failure to find any nonruptured caps between 30 and 66 µm is a strong indication that many of these caps contained µCalcs.

Rotational Atherectomy for the Management of Undilatable In-Stent Restenosis with Single or Multiple Stent Layers.

BACKGROUND: There is no consensus on the best treatment of undilatable coronary in-stent restenosis (ISR) regardless of the number of stent layers. We aimed to evaluate the procedural and clinical outcomes of rotational atherectomy (RA) to treat undilatable coronary ISR with single or multiple stent layers. METHODS: We retrospectively evaluated consecutive patients treated with RA for undilatable ISR with single or multiple stent layers in the Mount Sinai catheterization laboratory between January 2016 and September 2018. Procedural success was defined as angiographic success without in-hospital major adverse cardiac events (MACE): a composite of death, myocardial infarction (MI), and target lesion revascularization (TLR). Clinical outcomes were assessed at one-year post-procedure. RESULTS: A total of 26 patients were included in the study, in which 18 (69.2%) patients were with multiple stent layers. After RA, 9 (34.6%) were received a new drug-eluting stent, and 6 (23.1%) were treated with intravascular brachytherapy. Angiographic success was achieved in 24 (92.3%) patients, and procedural success was achieved in 22 (84.6%) patients. In-hospital MACE occurred in 4 (15.4%) patients, all due to periprocedural non-Q wave MI. Within one year, MACE occurred in 9 (34.6%) patients with 5 (19.2%) TLR. CONCLUSIONS: RA for undilatable ISR with single or multiple stent layers was performed with favorable procedural outcomes and a relatively high MACE rate driven by TLR within one year.

Relationship between hemoglobin A1C and characteristics of plaque vulnerability in stable coronary disease: an optical coherence tomography study.

Patients with diabetes mellitus are at increased risk of cardiovascular events. We aimed to analyze the impact of serum HbA1c levels on coronary plaque characteristics in stable coronary disease. Two hundred sixty-one patients who underwent optical coherence tomography (OCT) examination before elective percutaneous coronary intervention for a de novo obstructive lesions were included in this single-center retrospective analysis. Patients were divided into tertiles according to HbA1c level (tertile 1: HbA1c < 6.3%, tertile 2: 6.3 ≤ HbA1c < 7.8%, tertile 3: HbA1c ≥ 7.8%) and OCT findings were compared. Fibrous cap thickness (FCT) was significantly thinner in tertile 3 compared to tertile 1 and tertile 2 (103.9 ± 48.2 µm [tertile 1] vs. 107.5 ± 60.6 µm [tertile 2] vs. 86.2 ± 35.8 µm [tertile 3], p = 0.03). Higher prevalence of thin-cap fibroatheroma (TCFA) was observed in tertile 3 vs tertile 1 and tertile 2 (19.5% [tertile 1] vs. 19.5% [tertile 2] vs. 33.3% [tertile 3], p = 0.04). HbA1c inversely correlated with FCT (beta coefficient - 4.89, 95% confidence interval - 8.40 to - 1.39, p < 0.01). The logistic regression model revealed that the probability of having TCFA was positively associated with HbA1c with a small change in the range of low and medium HbA1c and a big change in the range of high HbA1c. Furthermore, minimal lumen area and reference lumen area were smaller in tertile 3. In patients with stable coronary disease, high serum HbA1c levels are associated with higher plaque burden and thinner FCT on OCT, while low and medium HbA1c levels result in similar plaque vulnerability.

Coronary plaque vulnerability in statin-treated patients with elevated LDL-C and hs-CRP: optical coherence tomography study.

There have been no previous attempts to assess coronary plaque morphology in statin-treated patients with combined residual cholesterol and inflammatory risk. The aim of this study was to characterize the morphology using optical coherence tomography (OCT) and to investigate the underlying molecular mechanisms. Two hundred seventy statin-treated patients with stable coronary artery disease who underwent OCT imaging prior to elective percutaneous coronary intervention were included in this single-center retrospective analysis. Subjects were stratified into four groups based on low-density lipoprotein cholesterol (LDL-C) and high-sensitivity C-reactive protein (hs-CRP) levels using 70 mg/dl and 2 mg/L as cut-offs, respectively. OCT images of the target lesions were assessed. For a subset of patients, peripheral blood mononuclear cells (PBMC) were isolated, and gene expression was characterized using microarray analysis. Patients with high LDL-C and high hs-CRP demonstrated a higher frequency of lipid-rich plaques (LRP) (91%, P = 0.03) by OCT. LRPs in these patients had a greater maximal lipid arc (186.6 ± 92.5°, P = 0.047). In addition, plaques from patients who did not achieve dual-target were less frequently calcified (P = 0.003). If calcification was present, it was characterized by a lower maximal arc (P = 0.016) and shorter length (P = 0.025). PBMC gene expression analysis demonstrated functional enrichment of toll-like receptors (TLRs) 1-9 to be associated with high LDL-C and hs-CRP. Obstructive coronary lesions in patients on statin therapy with combined residual cholesterol and inflammatory risk demonstrated a higher prevalence of LRP with greater maximal lipid arcs and more frequent spotty calcifications. PBMC from these patients revealed functional enrichment of TLR 1-9.