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The purpose of the current study was to use intravascular ultrasound (IVUS) to clarify anatomical and morphological lesion characteristics of uncrossable lesions.Uncrossable lesions are not always severely calcified. The prevalence of uncrossable lesions that are nonseverely calcified as well as other mechanisms for uncrossability has not been well clarified.A total of 252 de novo uncrossable lesions in native coronary arteries that underwent either rotational or orbital atherectomy due to inability of any balloon to cross the lesion and 38 lesions with severe calcium in which IVUS crossed preatherectomy were included. Severe calcium is defined as maximum arc of calcium ≥270°.Severe calcification was absent in 16% of uncrossable lesions, 83% of which had a significant vessel bend. Compared with crossable lesions with severe calcium, uncrossable lesions with severe calcium more often had a bend in the vessel (71% vs. 21%, p 0.001) and a longer length of continuous severe calcium (median length of calcium ≥270° 3.8 mm vs. 1.9 mm, p = 0.001). Other than severe calcium (especially long continuous calcium) or a bend in the vessel, anatomical factors associated with uncrossabilty were aorto-ostial lesion location and small vessels.Uncrossable lesions are not always severely calcified. The interaction of lesion morphology (continuous long and large arcs of calcium) and vessel geometry (bend in the vessel or ostial lesion location) affect lesion crossability.

Objectives This study was conducted to use optical coherence tomography (OCT) to compare vascular healing between bioresorbable polymer (BP) and durable polymer (DP) everolimus-eluting stents (EES) in patients with acute coronary syndromes (ACS). Background Whether BP-EES induce better vascular healing compared to contemporary DP-EES remains controversial, especially for ACS. Methods In this prospective, randomized, non-inferiority trial, we used OCT to compare 6-month vascular healing in patients with ACS randomized to BP versus DP-EES: percent strut coverage (primary endpoint, non-inferiority margin of 2.0%) and neointimal thickness and percent neointimal hyperplasia (NIH) volume. As an exploratory analysis, morphological factors related to the endpoints and the effect of underlying lipidic plaque on stent healing were evaluated. Results A total of 104 patients with ACS were randomly assigned to BP-EES (n = 52) versus DP-EES (n = 52). Of these, 86 patients (40 BP-EES and 46 DP-EES) were included in the final OCT analyses. Six-month percent strut coverage of BP-EES (83.6 ± 11.4%) was not non-inferior compared to those of DP-EES (81.6 ± 13.9%), difference 2.0% (lower 95% confidence interval-2.6%), pnon-inferiority = 0.07. There were no differences in neointimal thickness 70.0 ± 33.9 μm versus 67.2 ± 33.9 μm, p = 0.71; and percent NIH volume 7.5 ± 4.7% versus 7.3 ± 5.3%, p = 0.85. By multivariable linear regression analysis, stent type was not associated with percent strut coverage or percent NIH volume; however, percent baseline embedded struts or stent expansion was positively associated with percent NIH volume. Greater NIH volume was observed in lipidic compared with non-lipidic segments (8.7 ± 5.6% vs. 6.1 ± 5.2%, p = 0.005). Conclusions Six-month strut coverage of BP-EES was not non-inferior compared to those of DP-EES in ACS patients. Good stent apposition and expansion were independently associated with better vascular healing.

Objective We sought to evaluate whether automated coregistration of optical coherence tomography (OCT) with angiography reduces geographic miss (GM) during coronary stenting. Background Previous intravascular ultrasound or OCT studies have showed that residual disease at the stent edge or stent edge dissection was associated with stent thrombosis or edge restenosis. This has been termed GM. Methods Two hundred de novo coronary lesions were randomized in a 1:1 ratio to OCT-guided percutaneous coronary intervention (PCI) with versus without automated coregistration of OCT with angiography. GM, the primary endpoint, was defined as angiographic ≥type B dissection or diameter stenosis >50% or OCT minimum lumen area 60°) within 5 mm from the stent edge. Results The prevalence of GM was not different comparing OCT-guided PCI with versus without automated coregistration (27.6% vs 34.0%, P = 0.33). However, there was a trend toward a reduced prevalence of significant distal stent edge dissection in lesions with automated coregistration (11.1% vs 20.8%, P = 0.07). The discrepancy in the distance between planned versus actual implanted stent location with automated coregistration was significantly shorter than without coregistration (1.9 ± 1.6 mm vs 2.6 ± 2.7 mm, P = 0.03), especially the prevalence of ≥5 mm discrepancy that was less frequent with automated coregistration. Conclusions Automated coregistration of OCT with angiography did not reduce the primary endpoint of GM after stent implantation.

Objectives We sought to assess a new modality of radiofrequency intravascular ultrasound (IVUS) called iMAP-IVUS (Boston Scientific, Santa Clara, California) during the evaluation of patients presenting with high-risk acute coronary syndromes. Background There are limited data on plaque tissue characterization and phenotype classification using iMAP-IVUS. Methods In the iWonder study patients presenting with ST-elevation myocardial infarction (STEMI) or non-STEMI underwent three-vessel grayscale IVUS and iMAP-IVUS tissue characterization prior to percutaneous intervention. In total 385 lesions from 100 patients were divided into culprit (n = 100) and nonculprit (n = 285) lesions. Lesion phenotype was classified as (i) thin-cap fibroatheroma (iMAP-derived TCFA); (ii) thick-cap fibroatheroma; (iii) pathological intimal thickening; (iv) fibrotic plaque; and (v) fibrocalcific plaque. Results Culprit lesions had smaller minimum lumen cross-sectional area (MLA) with greater plaque burden compared to non-culprit lesions. Volumetric analysis showed that culprit lesions had longer length and larger vessel and plaque volumes compared to non-culprit lesions. iMAP-IVUS revealed that culprit lesions presented more NC and fibrofatty volume, both at lesion level and at the MLA site (all P

OBJECTIVE The primary objective was to demonstrate diagnostic equivalence between RFR and iFR in clinical practice. BACKGROUND The instantaneous wave-free ratio (iFR), a nonhyperemic pressure ratio (NHPR), has been shown to be noninferior to fractional flow reserve (FFR) in determining coronary artery stenosis severity in intermediate lesions. However, iFR has a number of inherent limitations, including sensitive landmarking of the pressure waveform and the assumption that maximal flow and minimal microcirculatory resistance occur during a fixed period within diastole. The resting full-cycle ratio (RFR) is a novel NHPR which evaluates the entire cardiac cycle independent of the ECG, landmark identification, and timing within the cardiac cycle. METHODS RE-VALIDATE RFR was designed to determine the diagnostic utility of RFR for the physiological assessment of coronary artery disease in clinical practice compared to iFR. RFR was also tested for equivalence (1% margin), diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), areas under the receiver operated characteristic curve (AUC), and correlations compared to calculated iFR (iFRcalc ). RESULTS From two centers, 501 blinded rest- and hyperemic pressure recordings from 431 patients were suitable for analysis according to a core laboratory. The mean FFR, RFR, and iFRcalc were 0.80 ± 0.09, 0.90 ± 0.08, and 0.90 ± 0.08, respectively. Based on a binary cut-off approach (RFR/iFR ≤0.89), RFR demonstrated equivalence with iFRcalc (95% confidence interval: 0.025-0.019) with overall diagnostic accuracy 97.8%, sensitivity 97.8%, specificity 97.8%, PPV 96.2%, NPV 98.7%, and AUC 0.96 (0.94-0.97, p

The ethylene glycol-based dimethacrylates are commonly used in biomaterials and dental restorative materials as a cross-linking agent. In this study, toxic effect of triethylene glycol dimethacrylate (TEGDMA) and poly(ethylene glycol) dimethacrylates (PEG-DMAs) with various ethylene glycol repeating units was investigated in terms of cytotoxicity, oxidative stress, and the expression of co-stimulatory factors in human leukemia cell line (THP-1 cells) to verify the effect of ethylene glycol repeating units. Note that the 1-octanol/water partition coefficient of PEG-based dimethacrylates decreased with increasing the ethylene glycol repeating units, indicating that the hydrophilicity of PEG-DMAs increased with ethylene glycol repeating units. The toxic effect of PEG-DMAs such as cytotoxicity, oxidative stress, and the expression of CD86 in treated THP-1 cells are reduced with increasing the ethylene glycol repeating units in PEG-DMAs. However, the expression of CD54 in treated THP-1 cells was not influenced with the ethylene glycol repeating units and the maximal expression level of CD54 was observed at the concentration range of 2-4 mM for all samples. Accordingly, hydrophilic character of PEG-DMAs with long ethylene glycol chains definitely alleviates the some toxic aspect of PEG-based DMAs. This finding would provide important insight into the design of new biomaterials and dental materials with superior biocompatibility.