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The study aimed to determine the predictors of procedural failure (coronary cannulation) in patients undergoing coronary angiography ± percutaneous coronary intervention (PCI) from the transradial (TR) approach.We conducted an observational study of 20,315 consecutive patients undergoing TR angiography between 2016 and 2020. TR failure was described as inability to cannulate the coronary arteries. Univariate and multivariate analyses were performed to determine independent predictors of TR failure.Out of the study population, TR failure was observed in 365 (1.8%) patients, out of which 281 (77%) crossed over successfully to the transfemoral (TF) route and 84 (23%) to left radial access (LRA). Unsuccessful procedures were most likely seen in patients who were elderly, female, BAME background, short stature or with a history of hypertension, diabetes, and renal disease. On regression analysis, age (OR: 1.024; 95% Cl: 1.014-1.035), female gender (OR: 0.729; 95% Cl: 0.555-0.957), BAME (OR: 0.786; 95% Cl: 0.612-0.959), height (OR: 0.988; 95% Cl: 0.977-0.999), hypertension (OR: 1.510; 95% Cl: 1.147-1.987) and RRA (OR: 1.977; 95% Cl: 1.105-3.538) were independent predictors of TR failure. On further analysis, these predictors of failure were not seen from the LRA approach.This study identifies that rates of TR failure are low and that predictors of failure differ between the RRA and LRA. The difference in predictors between the 2 routes suggests that in patients when coronary cannulation is unsuccessful via the RRA then the LRA could be considered as a second access site. Further study is needed to see if in selected patient groups the LRA could be used as the first-choice access route.

OBJECTIVES: This study aimed to determine the effect on long-term survival of using optical coherence tomography (OCT) during percutaneous coronary intervention (PCI). BACKGROUND: Angiographic guidance for PCI has substantial limitations. The superior spatial resolution of OCT could translate into meaningful clinical benefits, although limited data exist to date about their effect on clinical endpoints. METHODS: This was a cohort study based on the Pan-London (United Kingdom) PCI registry, which includes 123,764 patients who underwent PCI in National Health Service hospitals in London between 2005 and 2015. Patients undergoing primary PCI or pressure wire use were excluded leaving 87,166 patients in the study. The primary endpoint was all-cause mortality at a median of 4.8 years. RESULTS: OCT was used in 1,149 (1.3%) patients, intravascular ultrasound (IVUS) was used in 10,971 (12.6%) patients, and angiography alone in the remaining 75,046 patients. Overall OCT rates increased over time (p < 0.0001), with variation in rates between centers (p = 0.002). The mean stent length was shortest in the angiography-guided group, longer in the IVUS-guided group, and longest in the OCT-guided group. OCT-guided procedures were associated with greater procedural success rates and reduced in-hospital MACE rates. A significant difference in mortality was observed between patients who underwent OCT-guided PCI (7.7%) compared with patients who underwent either IVUS-guided (12.2%) or angiography-guided (15.7%; p < 0.0001) PCI, with differences seen for both elective (p < 0.0001) and acute coronary syndrome subgroups (p = 0.0024). Overall this difference persisted after multivariate Cox analysis (hazard ratio [HR]: 0.48; 95% confidence interval [CI]: 0.26 to 0.81; p = 0.001) and propensity matching (hazard ratio: 0.39; 95% CI: 0.21 to 0.77; p = 0.0008; OCT vs. angiography-alone cohort), with no difference in matched OCT and IVUS cohorts (HR: 0.88; 95% CI: 0.61 to 1.38; p = 0.43). CONCLUSIONS: In this large observational study, OCT-guided PCI was associated with improved procedural outcomes, in-hospital events, and long-term survival compared with standard angiography-guided PCI.

This study aimed to assess the impact of thrombus aspiration on mortality in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention (PCI).The clinical effect of routine intracoronary thrombus aspiration before primary PCI in patients with ST-segment elevation myocardial infarction is uncertain.We undertook an observational cohort study of 10,929 ST-segment elevation myocardial infarction patients from January 2005 to July 2011 at 8 centers across London, United Kingdom. Patients' details were recorded at the time of the procedure into local databases using the British Cardiac Intervention Society PCI dataset. Primary outcome was all-cause mortality at a median follow-up of 3.0 years (interquartile range: 1.2 to 4.6 years).In our cohort, 3,572 patients (32.7%) underwent thrombus aspiration during primary PCI. Patients who had thrombus aspiration were younger, had lower rates of previous myocardial infarction but were more likely to have poor left ventricular function. Procedural success rates were higher (90.9% vs. 89.2%; p=0.005) and in-hospital major adverse cardiac event rates were lower (4.4% vs. 5.5%; p=0.012) in patients undergoing thrombus aspiration. However, Kaplan-Meier analysis demonstrated no significant difference in mortality rates between patients with and without thrombus aspiration (14.8% aspiration vs. 15.3% PCI only; p=0.737) during the follow-up period. After multivariate Cox analysis (hazard ratio [HR]: 0.89, 95% confidence interval [CI]: 0.65 to 1.23) and the addition of propensity matching (HR: 0.85 95% CI: 0.60 to 1.20) thrombus aspiration was still not associated with decreased mortality.In this cohort of nearly 11,000 patients, routine thrombus aspiration was not associated with a reduction in long-term mortality in patients undergoing primary PCI, although procedural success and in-hospital major adverse cardiac event rates were improved.

The root causes of atherosclerosis lie in cellular events that precede the clinical presentation of the disease by many years. The initiating events centre around the response of endothelial cells to chronic injury, such as that sustained in hypercholesterolemia. These responses involve the activation, attachment and migration of leucocytes and platelets.

DiDomenico and Eyrich question the definition of radiocontrast-induced nephropathy (RCIN) and whether contrast nephropathy occurred in the RAPPID study. The definition of RCIN employed (a rise in serum creatinine ≥25%) is a widely accepted one and has been used extensively [(1–4)][1].

Hypertrophic cardiomyopathy is a familial cardiac disorder with heterogeneous expression and a diversity of morphological, functional and clinical features. Some individuals with hypertrophic cardiomyopathy may be asymptomatic while others are disabled by symptoms of angina and breathlessness. This article summarizes the genetics, pathophysiology and present management of this important condition.

Abstract Platelet activation state and responsiveness to physiological agonists were measured in 65 patients with documented coronary artery disease (54 male and 11 female; mean age, 58 years). Twelve patients (mean age, 52 years), selected at random from the male cohort, were compared with 12 age-matched male control subjects (mean age, 52 years) and with 10 normal, young male subjects (mean age, 25 years). Whole-blood flow cytometry was used to measure platelet activation status ex vivo and platelet responsiveness to physiological agonists in vitro. Peripheral blood samples were analyzed for bound fibrinogen and expression of P-selectin, GPIb, and GPIIb-IIIa at rest and in response to ADP (0.1 to 10 μmol/L) and thrombin (0.02 to 0.32 μ/mL). No significant differences were seen in the basal levels of fibrinogen binding between any of the groups, but P-selectin expression was significantly lower in patients compared with age-matched control subjects ( P =.0005). When stimulated with agonists, patients’ platelets had significantly decreased fibrinogen binding ( P P

The National Institute for Clinical Excellence (NICE) was set up in 1999, with the aim of creating an independent body to evaluate and recommend therapies for NHS patients. NICE examines research evidence, assesses effectiveness (likely effects on patients in the community) and takes into account efficiency (cost effectiveness) before making recommendations.

The interaction of weak shock waves with screens and honeycombs is examined to facilitate the design of a pulsed flowing gas laser system operating at a high repetition rate. Interactions with zero and finite base flow (M

A three-dimensional viscous cascade code has been developed for linear cascades with flat, parallel endwalls. It employs scalar implicit approximate factorization, a finite-volume formulation, second-order upwind differencing, and a two-equation q-& turbulence model based on integration to the wall. A special form of the thinlayer approximation for the compressible Navier-Stokes equations is used which gives accurate skin-friction predictions on highly skewed meshes, now based on sheared H-grids. This code has been validated by considering three-dimensional viscous flows in Langston's large-scale turbine blade geometry. This validation includes threedimensional heat-transfer predictions. Agreement with experiment is quite good.

This paper is motivated by a general interest in pulsed energy addition to a surface in vacuum at high power fluxes (> 1 MW/cm absorbed). The theoretical treatment assumes a perfect gas without plasma formation, and examples are for aluminum. Transient heat conduction into the surface, vapor flux through a Knudsen layer at the surface, and transient one-dimensional flow of vapor into the surrounding vacuum are included as part of the modeling. Results show that the Knudsen layer remains choked so long as the absorbed power is constant or increasing, and it is unchoked when the absorbed power is decreasing. The problem is fully coupled in the latter case. Quasisteady vapor efflux from the surface is established within a fraction of the pulse time at sufficiently high power fluxes. Impulse coupling coefficients due to vapor recoil are noted.

Thermal homogeneity in a single-pulse excimer laser cavity is of interest because it directly impacts medium optical quality. This study is primarily oriented toward an XeF* laser in which the cavity is hot (500 K) and is pumped by an e-beam from a cold cathode structure in a vacuum chamber next to the cavity. The foil and support structure are on a vertical wall between these hot and cold zones. In consequence, due to radiative heat transfer, the wall assumes a nonuniform termperature and induces natural convection and thermal inhomogeneity within the cavity. Studies of radiative, conductive, and natural convective heat-transfer processes are summarized which lead to a plausible engineering approach to achieving medium homogeneity of (6p/p)rms - 5 X10 ~ 5 in the closed XeF* laser cavity.

In this paper, a theoretical model is developed for rapid surface vaporization into a surrounding ambient atmosphere. The primary emphasis is on metallic surfaces. Power input levels are taken to be low enough so that thermodynamic equilibrium can be assumed before phase change to gas. At high evaporation rates there will be a narrow Knudsen layer region in the gaseous flow just outside the phase interface in which translational nonequilibrium prevails. The modeling treats this layer as a gasdynamic discontinuity and approximate jump conditions are derived. The flow Mach number just outside the Knudsen layer is dictated by the state well away from the surface. Its determination is discussed both for a simple model of transient flow induced by a laser pulse and for the general case of time-varying power input. Examples assume the metallic surface is aluminum and the surrounding air pressure ranges from 1 atm to hard vacuum.

Transverse acoustic waves in pulsed lasers result from nonuniform pumping transverse to the flow direction. This theoretical study is based on linear acoustics and disregards hot/cold gas interfaces. First, transverse waves in an infinite parallel hard-walled duct are considered, in which case cavity medium inhomogeneity typically decays as t ~ ' / 2 . An idealized treatment is next given to show that exponential decay can be expected with an anode absorber. There is an optimum absorber resistivity and improved attenuation rate results with increased backing volume. Tilted sidewalls are the final topic. Decay is again exponential, and rapid attenuation requires fairly large tilt angles. Examples are chosen to apply to CO2 electric discharge, chemical, and excimer lasers.

Sidewall mufflers are used in pulsed exciplex lasers to rapidly attenuate pressure waves and restore cavity medium homogeneity at successive pulses. The technical basis for designing these is reviewed in the paper with primary focus on the near-cavity region and emphasis on physical understanding. The approach combines rudimentary theory and flow visualization, starting with simplest situation and building toward a more complete picture. Important results are as follows: longitudinal wave attenuation in a finite capacity muffler involves a balance between precursor pulse decay and recompression wave strength which defines an optimum configuration. Acoustic absorber is required in the backing volume, and a basis for choosing its resistivity is indicated. The contribution of a close-in muffler to transverse wave decay within the laser cavity is also characterized. Further, an entropy wave is shown to be generated within a muffler which is confined to the vicinity of the sidewalls. Other entropy sources in a closed loop flow system are noted.

Typical stagnation conditions required to simulate the orbital re-entry corridor are P0 > 1000 atm and T0 > 5000°K. Although it is not feasible to have such stagnation conditions in a reservoir operating under nearly continuous conditions, it is feasible to obtain high stagnation temperatures in a gas flowing from a relatively cool high-pressure reservoir by adding laser energy to the flow. In this new approach, two important advantages are realized: 1) the energy source (i.e., the laser) is physically separated from the wind tunnel and is not temperature-limited as compared to direct heating devices, and 2) the laser beam can be accurately aimed down the central core of the flow, avoiding direct heating of the tunnel walls. A conceptual wind-tunnel configuration is illustrated in Fig. 1. The laser beam enters the tunnel system through a window near the plenum chamber and propagates downstream through the subsonic flow region of the nozzle. Under reservoir con