Optical coherence tomography: influence of contrast concentration on image quality and diagnostic confidence.

OCT requires intracoronary injection of contrast agent to remove blood from the coronary lumen during data acquisition, which is a possible limitation of this method. Aim of this study was to analyze the influence of iodine concentration on image quality and diagnostic certainty of optical coherence tomography (OCT). OCT sequences acquired using contrast agent with a reduced concentration of 150 mg iodine/ml and a standard concentration of 350 mg iodine/ml were analyzed. Cross-sectional images with a spacing of 10 mm were evaluated regarding image quality and diagnostic confidence. A total of 67 OCT sequences acquired in 24 patients were analyzed. 31 sequences were acquired using contrast agent with a concentration of 150 mg iodine/ml and 36 sequences with a concentration of 350 mg iodine/ml. The percentage of remaining blood streaks in the cross sections was significantly lower for 350 mg iodine/ml compared to 150 mg iodine/ml (19 ± 21 vs. 34 ± 26%, p = 0.013). Contrast with 350 mg iodine/ml showed a significantly higher percentage of completely flushed pullback length as compared to 150 mg iodine/ml (78 ± 24 vs. 58 ± 27%, p = 0.004). Diagnostic certainty was significantly higher for 350 mg iodine/ml than for 150 mg iodine/ml (Likert scale average 1.4 ± 0.7 vs. 2.1 ± 1.2, p < 0.001; Likert scale: 1 = absolutely confident, 2 = confident with slight doubts, 3 = doubtful/not confident, 4 = non-diagnostic). Regarding image quality and diagnostic certainty, contrast agent with a concentration of 350 mg iodine/ml is superior to 150 mg iodine/ml.

Overlapping implantation of bioresorbable novolimus-eluting scaffolds: an observational optical coherence tomography study.

Overlapping implantation of bioresorbable vascular scaffolds is frequently necessary, but its influence on vessel and scaffold structure has not been thoroughly analyzed previously. The aim of this study was to analyze the acute effects of overlapping implantation on BRS as determined by optical coherence tomography (OCT). A total of 38 patients with de novo coronary artery stenoses who underwent OCT in the context of implantation of novolimus-eluting BRS (DESolve, Elixir Medical Corporation, Sunnyvale, California, USA) were investigated. In 15 patients, overlapping implantation of two BRS was performed, while 23 patients with implantation of one single BRS served as the control group. OCT data were retrospectively analyzed regarding acute scaffold implantation results. There were no significant differences between the overlap and control group in terms of residual in-scaffold area stenosis, scaffold area, mean or minimal lumen area, eccentricity index, incomplete scaffold apposition area or malapposition. While strut fracture was slightly more frequent in BRS with overlap its incidence was low overall. In patients with overlapping BRS, overlap segments did not display smaller lumen areas than segments without overlap (mean lumen area overlap: 8.16 ± 2.97 mm2 vs. no overlap: 7.70 ± 2.55 mm2; p = 0.71; minimal lumen area overlap: 6.83 ± 2.71 mm2 vs. no overlap: 6.17 ± 2.58 mm2; p = 0.37). Acute mechanical performance of novolimus-eluting BRS is not impaired by overlapping implantation. It can be assumed that vessel expansion compensates for the double scaffold layer in the overlap area resulting in a similar lumen area in overlap areas and in those with a single strut layer.

Bioresorbable vascular scaffold thrombosis in a consecutive cohort of 550 patients.

OBJECTIVE: To determine the rate of bioresorbable vascular scaffold (BVS) thrombosis in a large, real-world population. BACKGROUND: There is some concern about device thrombosis after percutaneous coronary intervention (PCI) using BVS. No data have been published for PCI using both BVS and metal stents. METHODS: A cohort of 550 consecutive patients who underwent PCI for stable chest pain or acute coronary syndromes with implantation of at least one BVS (Absorb, Abbott Vascular) was systematically followed up by telephone interview and review of medical charts. Data on device thrombosis were retrospectively analyzed in relationship to clinical and angiographic characteristics. RESULTS: Follow-up was achieved in 533 patients (97%, median follow-up 233 days). A total of 964 BVS were implanted in 645 vessels. In addition, 234 metal stents were implanted in 149 patients, including "hybrid intervention" with the combined use of BVS and stents in the same artery in 122 patients. Documented were 15 definite, 1 probable, and 8 possible cases of device thrombosis (rate of definite/probable device thrombosis: 3.0%). Of these, 6 definite and 6 possible thromboses could be unambiguously attributed to BVS (1.1%), whereas a total of 11 definite, 1 probable, and 8 possible thromboses were potentially attributable to BVS (2.3%). Definite device thrombosis occurred in 7/122 patients with "hybrid intervention" (5.7%). CONCLUSIONS: In a large real-world cohort treated with BVS, the rate of scaffold thrombosis was higher than published for randomized trials. A high rate of thrombosis was observed after combined implantation of BVS and stents within one vessel. © 2016 Wiley Periodicals, Inc.

Dual-axis rotational coronary angiography versus conventional coronary angiography: a randomized comparison.

BACKGROUND: Dual-axis of rotational coronary angiography (RA), with one single cine acquisition during continuous C-arm motion along a pre-described path, is an alternative to conventional coronary angiography (CA). We assessed the performance of RA versus CA in a modern, experienced cath lab setting. METHODS: Sixty-seven patients with suspected coronary artery disease undergoing invasive coronary angiography were randomized to CA (n = 35) or dual-axis RA (n = 32). CA was performed with four left and two right coronary artery acquisitions with manual contrast medium injection. In RA, one cine acquisition each was performed for the left (5 projections) and right coronary artery (3 projections) with a fixed amount of contrast medium applied by a power injector. In both groups, single cine acquisitions in additional angulations were performed to fully interpret the coronary system, if necessary. Procedural parameters and outcome were compared. RESULTS: Mean age was 63 ± 12 years (64% males). Six additional projections were required in the RA group compared to 13 in the CA group (p = 0.173). Fluoroscopy duration (CA: 3 ± 3 min, RA: 3 ± 2 min, p = 0.748) and dose area product (CA: 1291 ± 761 µGym2, RA: 1476 ± 679 µGym2, p = 0.235) did not differ significantly between both groups. For CA, the amount of contrast medium (42 ± 13 vs. 46 ± 8 ml, p = 0.022) and procedure time (8 ± 5 vs. 11 ± 3 min, p < 0.001) were significantly lower. No major adverse event occurred during hospital stay. CONCLUSIONS: Dual-axis RA represents a feasible and safe alternative method to CA for obtaining coronary angiograms. However, no superiority was observed when performed by an experienced interventionalist with a modern system.

ORAI1 deficiency and lack of store-operated Ca2+ entry cause immunodeficiency, myopathy, and ectodermal dysplasia.

BACKGROUND: Defects in the development or activation of T cells result in immunodeficiency associated with severe infections early in life. T-cell activation requires Ca2+ influx through Ca2+-release activated Ca2+ (CRAC) channels encoded by the gene ORAI1. OBJECTIVE: Investigation of the genetic causes and the clinical phenotype of immunodeficiency in patients with impaired Ca2+ influx and CRAC channel function. METHODS: DNA sequence analysis for mutations in the genes ORAI1, ORAI2, ORAI3, and stromal interaction molecule (STIM) 1 and 2, as well as mRNA and protein expression analysis of ORAI1 in immunodeficient patients. Immunohistochemical analysis of ORAI1 tissue distribution in healthy human donors. RESULTS: We identified mutations in ORAI1 in patients from 2 unrelated families. One patient is homozygous for a frameshift nonsense mutation in ORAI1 (ORAI1-A88SfsX25), and a second patient is compound heterozygous for 2 missense mutations in ORAI1 (ORAI1-A103E/L194P). All 3 mutations abolish ORAI1 expression and impair Ca2+ influx and CRAC channel function. The clinical syndrome associated with ORAI1 deficiency is characterized by immunodeficiency with a defect in the function but not in the development of lymphocytes, congenital myopathy, and anhydrotic ectodermal dysplasia with a defect in dental enamel calcification. In contrast with the limited clinical phenotype, we found ORAI1 protein expression in a wide variety of cell types and organs. CONCLUSION: Ca2+ influx through ORAI1 is crucial for lymphocyte function in vivo. Despite almost ubiquitous ORAI1 expression, the channel has a nonredundant role in only a few cell types judging from the limited clinical phenotype in ORAI1-deficient patients.

Major coronary evaginations following implantation of bioresorbable vascular scaffolds - Clinical and OCT characteristics.

BACKGROUND: Coronary evaginations can occur after implantation of bioresorbable vascular scaffolds (BRS) and may be associated with scaffold thrombosis. Aim of this study was to clarify the clinical manifestation, extent and time course of coronary artery remodeling in vessel segments that develop angiographically detectable evaginations following BRS implantation through optical coherence tomography (OCT) analysis. METHODS: In 8 patients, 10 BRS (Absorb, Abbott Vascular, Santa Clara, CA, USA) which displayed coronary evaginations in clinically driven late invasive coronary angiograms were identified and findings were compared to 10 BRS in 8 patients without coronary evaginations. Vessel and device geometry was analyzed in serial OCT cross-sections at a spacing of 200 µm. Measured BRS dimensions were normalized to the reference vessel size at implantation. RESULTS: In OCT, major evaginations on average affected 24 ±â€¯19% of the scaffold length. Scaffolds with major evaginations had a significantly larger lumen area than scaffolds without evaginations (mean normalized lumen area 1.19 ±â€¯0.58 vs. 0.77 ±â€¯0.38; p < 0.001), and also displayed a significantly larger scaffold area (mean normalized scaffold area: 1.36 ±â€¯0.6 vs. 1.13 ±â€¯0.43; p < 0.001), and scaffold diameter (mean normalized scaffold diameter: 1.17 ±â€¯0.33 vs.1.04 ±â€¯0.19; p < 0.001). Lumen area (r = 0.47; p < 0.001), scaffold area (r = 0.52; p < 0.001), and scaffold diameter (r = 0.74; p < 0.001) in the evagination group were positively correlated to the time since scaffold implantation. CONCLUSION: Coronary evaginations following BRS implantation are associated with an increased scaffold area, indicating that the scaffold follows the outward remodeling of the artery. The process affects the entire scaffold length and seems to be continuously progressing following implantation.

Percutaneous coronary intervention of unprotected left main stenoses - Procedural data and outcome depending on SYNTAX I Score.

BACKGROUND: We hypothesized that SYNTAX I score is a predictor for procedure complexity in left main PCI. Procedure complexity, duration and contrast load may contribute to adverse outcome of complex left main percutaneous coronary intervention (PCI). METHODS: In 105 consecutive patients who underwent PCI of unprotected left main coronary artery stenoses between 2014 and 2016, clinical parameters as well as PCI characteristics and follow-up data were analyzed. RESULTS: The mean SYNTAX I score was 29 ±â€¯12, with 66 patients having a SYNTAX I score ≤ 32 and 39 patients a SYNTAX I score > 32. In patients with high SYNTAX I score vs. low-to-intermediate SYNTAX I score, single stent techniques were performed significantly less frequently (18% vs. 68%; p < 0.001), while Crush (44% vs. 5%; p < 0.001) and Culotte techniques (20% vs. 5%; p = 0.003) were performed significantly more frequently. Procedural success was achieved in all 105 cases without periprocedural mortality. During follow up, repeat PCI was necessary significantly more frequently in patients with high compared to patients with low-to-intermediate SYNTAX I score (34% vs.13%; p = 0.003). Nevertheless, overall mortality did not differ between patients with high vs. low-to-intermediate SYNTAX I score (20% vs. 18%). CONCLUSIONS: PCI strategies for the treatment of left main coronary artery stenoses get significantly more complex with increasing SYNTAX I scores. While this translates into a significantly longer procedure duration and contrast load, short-term outcome seems not to be influenced by the SYNTAX I score.

Comparison of invasively measured FFR with FFR derived from coronary CT angiography for detection of lesion-specific ischemia: Results from a PC-based prototype algorithm.

BACKGROUND: We evaluated the diagnostic accuracy of a novel prototype for on-site determination of CT-based FFR (cFFR) on a standard personal computer (PC) compared to invasively measured FFR in patients with suspected coronary artery disease. METHODS: A total of 91 vessels in 71 patients (mean age 65 ±â€¯9 years) in whom coronary CT angiography had been performed due to suspicion of coronary artery disease, and who subsequently underwent invasive coronary angiography with FFR measurement were analyzed. For both cFFR and FFR, a threshold of ≤0.80 was used to indicate a hemodynamically relevant stenosis. The mean time needed to calculate cFFR was 12.4 ±â€¯3.4 min. A very close correlation between cFFR and FFR could be shown (r = 0.85; p < 0.0001) with Bland-Altman analysis showing moderate agreement between FFR and cFFR with mild systematic overestimation of FFR values in CT (mean difference 0.0049, 95% limits of agreement ±2SD -0.007 to 0.008). Compared to FFR, the sensitivity of cFFR to detect hemodynamically significant lesions was 91% (19/21, 95% CI: 70%-99%), specificity was 96% (67/70, 95% CI: 88%-99%), positive predictive value 86% (95% CI: 65%-97%) and negative predictive value was 97% (95% CI: 90%-100%) with an accuracy of 93%. CONCLUSION: cFFR obtained using an on-site algorithm implemented on a standard PC shows high diagnostic accuracy to detect lesions causing ischemia as compared to FFR. Importantly, the time needed for analysis is short which may be useful for improving clinical workflow.

Predictors of Technical Failure in Transradial Coronary Angiography and Intervention.

Transradial access for coronary angiography and intervention is preferred over the femoral approach but can be technically challenging. Identification of predictors of transradial access failure is important, especially in the context of acute coronary syndromes. We therefore retrospectively analyzed 13,095 consecutive patients (66 ± 12 years, 64% male) in whom transradial access was attempted for coronary angiography or intervention to identify predictors of transradial access failure. Angiograms and patient files were systematically reviewed to analyze patient characteristics associated with failure. Transradial access failure rate was 6.8% (909 of 13,095). Patients with transradial access failure were more frequently female (9.5% vs 5.5%; p <0.001), significantly older (68 ± 12 vs 66 ± 12 years, p <0.001), and had a smaller body surface area (1.89 ± 0.21 vs 1.94 ± 0.2 m2; p <0.001). Transradial failure was not significantly more frequent in ST-elevation myocardial infarction versus other patients (8.1% vs 6.9%, p = 0.195). After multivariable adjustment, only female sex (odds ratio [OR] 1.44, p <0.001), higher patient age (OR 1.01/year, p = 0.002), and lower height (OR 0.98/cm, p = 0.004) independently predicted transradial access failure. In conclusion, female sex, higher age, and smaller height independently predict transradial access failure in coronary angiography and intervention. Failure rate in ST-elevation myocardial infarction is not significantly increased.

Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects.

OBJECTIVES: The objective was to investigate the acute mechanical effects of post-dilatation on bioresorbable scaffolds (BRS) as determined by optical coherence tomography (OCT). BACKGROUND: Post-dilatation with high-pressure balloons is regarded as a key component of BRS implantation for treatment of coronary artery stenoses. However, the impact of post-dilatation on BRS in vivo has not been thoroughly investigated. METHODS: OCT was performed after the implantation procedure of 51 everolimus-eluting or novolimus-eluting polylactic acid-based BRS with (n = 27) or without non-compliant balloon post-dilatation (n = 24). The number of malapposed struts, strut fractures, edge dissections, residual in-scaffold area stenosis, and incomplete scaffold apposition area was analyzed over the complete length of each BRS with a spacing of 1 mm. RESULTS: OCT revealed a significantly lower incomplete scaffold apposition area if post-dilatation was performed (0.16 ± 0.49 mm2 with post-dilatation vs. 2.65 ± 2.78 mm2 without post-dilatation, p < 0.001), as well as a significantly lower absolute number of malapposed struts (1 ± 2 with post-dilatation vs. 13 ± 13 without post-dilatation, p < 0.001). No significant differences regarding residual in-scaffold area stenosis, strut fracture, edge dissection, symmetry index, or eccentricity index were observed in patients with vs. without post-dilatation. CONCLUSION: Post-dilatation of BRS with non-compliant balloons significantly reduces the number of malapposed struts and incomplete scaffold apposition area without inducing higher rates of edge dissection or strut fracture.

Comparison of standard- and high-dose intracoronary adenosine for the measurement of coronary fractional flow reserve (FFR).

BACKGROUND: Measurement of fractional flow reserve (FFR) by intravenous infusion or intracoronary injection of adenosine is the reference method to determine the hemodynamic relevance of coronary artery stenoses. The goal of this prospective study was to compare standard (40 µg adenosine for the right and 80 µg for the left coronary artery) to high doses of intracoronary adenosine for FFR measurement. METHODS AND RESULTS: In 130 intermediate coronary artery stenoses, two sequential FFR measurements were performed with standard-dose intracoronary application of adenosine (40 µg for the right and 80 µg for the left coronary artery), followed by one FFR measurement with a bolus of 200 µg for the right and 400 µg for the left coronary artery. There was strong correlation (r = 0.97, p < 0.001) between FFR values determined with standard-dose adenosine (0.86 ± 0.08) versus high-dose adenosine (0.85 ± 0.08). High-dose adenosine did not yield FFR values ≤0.80 or ≤0.75 significantly more frequently than standard-dose adenosine. Patients reported more discomfort after high-dose adenosine application compared to standard-dose adenosine (p < 0.001). CONCLUSIONS: For FFR measurements with intracoronary adenosine injection, results achieved with doses of 40 µg adenosine for the right and 80 µg for the left coronary artery display no clinically relevant difference to doses of 200 and 400 µg, respectively.

Comparison of Fractional Flow Reserve Based on Computational Fluid Dynamics Modeling Using Coronary Angiographic Vessel Morphology Versus Invasively Measured Fractional Flow Reserve.

Invasive fractional flow reserve (FFRinvasive), although gold standard to identify hemodynamically relevant coronary stenoses, is time consuming and potentially associated with complications. We developed and evaluated a new approach to determine lesion-specific FFR on the basis of coronary anatomy as visualized by invasive coronary angiography (FFRangio): 100 coronary lesions (50% to 90% diameter stenosis) in 73 patients (48 men, 25 women; mean age 67 ± 9 years) were studied. On the basis of coronary angiograms acquired at rest from 2 views at angulations at least 30° apart, a PC-based computational fluid dynamics modeling software used personalized boundary conditions determined from 3-dimensional reconstructed angiography, heart rate, and blood pressure to derive FFRangio. The results were compared with FFRinvasive. Interobserver variability was determined in a subset of 25 narrowings. Twenty-nine of 100 coronary lesions were hemodynamically significant (FFRinvasive ≤ 0.80). FFRangio identified these with an accuracy of 90%, sensitivity of 79%, specificity of 94%, positive predictive value of 85%, and negative predictive value of 92%. The area under the receiver operating characteristic curve was 0.93. Correlation between FFRinvasive (mean: 0.84 ± 0.11) and FFRangio (mean: 0.85 ± 0.12) was r = 0.85. Interobserver variability of FFRangio was low, with a correlation of r = 0.88. In conclusion, estimation of coronary FFR with PC-based computational fluid dynamics modeling on the basis of lesion morphology as determined by invasive angiography is possible with high diagnostic accuracy compared to invasive measurements.

A single-ligand ultra-microporous MOF for precombustion CO2 capture and hydrogen purification.

Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate)2 with a cubic framework that exhibits exceptionally high CO2/H2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO2 adsorption-desorption cycling and has CO2 self-diffusivities of ~3 × 10(-9) m(2)/s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO2-CO2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams.