Chiral Fermions and Multigrid

Lattice regularization of chiral fermions is an important development of the theory of elementary particles. Nontheless, brute force computer simulations are very expensive, if not prohibitive. In this letter I exploit the non-interacting character of the lattice theory in the flavor space and propose a multigrid approach for the simulation of the theory. Already a two-grid algorithm saves an order of magnitude of computer time for fermion propagator calculations.Comment: Latex, 6 pages, 1 figur

The Deconfinement Phase Transition in One-Flavour QCD

We present a study of the deconfinement phase transition of one-flavour QCD, using the multiboson algorithm. The mass of the Wilson fermions relevant for this study is moderately large and the non-hermitian multiboson method is a superior simulation algorithm. Finite size scaling is studied on lattices of size $8^3\times 4$, $12^3\times 4$ and $16^3\times 4$. The behaviours of the peak of the Polyakov loop susceptibility, the deconfinement ratio and the distribution of the norm of the Polyakov loop are all characteristic of a first-order phase transition for heavy quarks. As the quark mass decreases, the first-order transition gets weaker and turns into a crossover. To investigate finite size scaling on larger spatial lattices we use an effective action in the same universality class as QCD. This effective action is constructed by replacing the fermionic determinant with the Polyakov loop identified as the most relevant Z(3) symmetry breaking term. Higher-order effects are incorporated in an effective Z(3)-breaking field, $h$, which couples to the Polyakov loop. Finite size scaling determines the value of $h$ where the first order transition ends. Our analysis at the end - point, $h_{ep}$, indicates that the effective model and thus QCD is consistent with the universality class of the three dimensional Ising model. Matching the field strength at the end point, $h_{ep}$, to the $\kappa$ values used in the dynamical quark simulations we estimate the end point, $\kappa_{ep}$, of the first-order phase transition. We find $\kappa_{ep}\sim 0.08$ which corresponds to a quark mass of about 1.4 GeV .Comment: LaTex, 25 pages, 18 figure

The Relationship between Coronary Artery Wall Shear Strain and Plaque Morphology : A Systematic Review and Meta-Analysis

Background and Aim: Arterial wall shear strain (WSS) has been proposed to impact the features of atherosclerotic plaques. The aim of this meta-analysis was to assess the impact of different types of WSS on plaque features in coronary artery disease (CAD). Methods: We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar, and the Cochrane Central Registry, from 1989 up to January 2020 and selected clinical trials and observational studies which assessed the relationship between WSS, measured by intravascular ultrasound (IVUS), and plaque morphology in patients with CAD. Results: In four studies, a total of 72 patients with 13,098 coronary artery segments were recruited, with mean age 57.5 +/- 9.5 years. The pooled analysis showed that low WSS was associated with larger baseline lumen area (WMD 2.55 [1.34 to 3.76, p < 0.001]), smaller plaque area (WMD 1.16 [-1.84 to -0.49, p = 0.0007]), lower plaque burden (WMD -12.7 [-21.4 to -4.01, p = -0.04]), and lower necrotic core area (WMD -0.32 [-0.78 to 0.14, p = 0.04]). Low WSS also had smaller fibrous area (WMD -0.79 [-1.88 to -0.30, p = 0.02]) and smaller fibro-fatty area (WMD 0.22 [-0.57 to 0.13, p = 0.02]), compared with high WSS, but the dense calcium score was similar between the two groups (WMD -0.17 [-0.47 to 0.13, p = 0.26]). No differences were found between intermediate and high WSS. Conclusions: High WSS is associated with signs of plaque instability such as higher necrotic core, higher calcium score, and higher plaque burden compared with low WSS. These findings highlight the role of IVUS in assessing plaque vulnerability

High Coronary Wall Shear Stress Worsens Plaque Vulnerability : A Systematic Review and Meta-Analysis

Aim: The aim of this meta-analysis is to assess the impact of wall shear stress (WSS) severity on arterial plaque vulnerability. Methods: We systematically searched electronic databases and selected studies which assessed the relationship between WSS measured by intravascular ultrasound and coronary artery plaque features. In 7 studies, a total of 615 patients with 28 276 arterial segments (median follow-up: 7.71 months) were identified. At follow-up, the pooled analysis showed high WSS to be associated with regression of plaque fibrous area, weighted mean difference (WMD) −0.11 (95% CI: −0.20 to −0.02, P = .02) and fibrofatty area, WMD −0.09 (95% CI: −0.17 to −0.01, P = .02), reduction in plaque total area, WMD −0.09 (95% CI: −0.14 to −0.04, P = .007) and increased necrotic core area, and WMD 0.04 (95% CI: 0.01-0.09, P = .03) compared with low WSS. Dense calcium deposits remained unchanged in high and low WSS (0.01 vs 0.02 mm2; P > .05). High WSS resulted in profound remodeling (40% vs 18%, P < .05) and with more constructive remodeling than low WSS (78% vs 40%, P < .01). Conclusions: High WSS in coronary arteries is associated with worsening plaque vulnerability and more profound arterial wall remodeling compared with low WSS

One month is not inferior to prolonged dual antiplatelet therapy after PCI with drug-eluting stents: a systematic review and meta-analysis of randomized clinical trials

Aim: The aim of this meta-analysis was to evaluate the safety of 1-month dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug eluting stents (DES), followed by aspirin or a P2Y12 receptor inhibitor based on the available evidence. Methods: PubMed, MEDLINE, Embase, Scopus, Google Scholar, CENTRAL and ClinicalTrials.gov databases search identified 4 RCTs of 27,131 patients who underwent PCI with DES which compared 1-month vs. \u3e1-month DAPT. The primary endpoint was major bleeding and co-primary endpoint stent thrombosis. Secondary endpoints included all-cause mortality, myocardial infarction (MI), stroke and major adverse clinical events (MACE). Results: Compared to \u3e1 month DAPT, the 1 month DAPT was associated with similar rate of major bleeding (OR=0.74, 95%CI: 0.51 to 1.04, p=0.11, I2=67%), stent thrombosis (OR=1.10, 95%CI: 0.82 to 1.47, p=0.53, I2=0.0%), similar risk for all-cause mortality (OR=0.89, 95%CI: 0.77 to 1., p=0.14, I2=0%), CV death (OR=0.80, 95%CI: 0.55 to 1.60, p=0.24, I2=0.0%), MI (OR=1.02, 95%CI: 0.87 to 1.19, p=0.81, I2=0.0%) and stroke (OR=0.76, 95%CI: 0.54 to 1.08, p=0.13, I2=29%). The risk of MACE was lower risk of MACE was lower (OR=0.84, 95%CI: 0.73 to 0.97, p=0.02, I2=36%) in the 1-month DAPT compared to the \u3e1-month DAPT. Only patients with stable CAD had lower risk of MACE with 1-month DAPT (OR=0.81, 95%CI: 0.67 to 0.98, p=0.03, I2=21%) compared to \u3e 1-month DAPT. Conclusion: This meta-analysis proved non-inferiority of 1-month DAPT followed by aspirin or a P2Y12 receptor inhibitor compared to longer term DAPT in patients undergoing PCI with DES

Non-inferiority of 1 month versus longer dual antiplatelet therapy in patients undergoing PCI with drug-eluting stents : a systematic review and meta-analysis of randomized clinical trials

Aim: The aim of this meta-analysis was to evaluate the safety of 1-month dual antiplatelet therapy (DAPT) followed by aspirin or a P2Y12 receptor inhibitor, after percutaneous coronary intervention (PCI) with drug-eluting stents (DES), based on the available evidence. Methods: PubMed, MEDLINE, Embase, Scopus, Google Scholar, CENTRAL, and ClinicalTrials.gov database search identified four RCTs of 26,431 patients who underwent PCI with DES and compared 1-month versus >1-month DAPT. The primary endpoint was major bleeding and co-primary endpoint stent thrombosis, and secondary endpoints included all-cause mortality, cardiovascular death, myocardial infarction (MI), stroke, and major adverse clinical events (MACE). Results: Compared with >1-month DAPT, the 1-month DAPT was associated with a similar rate of major bleeding (OR = 0.74, 95%CI: 0.51–1.07, p = 0.11, I2 = 67%), stent thrombosis (OR = 1.10, 95%CI: 0.82–1.47, p = 0.53, I2 = 0.0%), similar risk for all-cause mortality (OR = 0.89, 95%CI: 0.77–1.04, p = 0.14, I2 = 0%), CV death (OR = 0.80, 95% CI: 0.55–1.60, p = 0.24, I2 = 0.0%), MI (OR = 1.02, 95% CI: 0.88–1.19, p = 0.78, I2 = 0.0%), and stroke (OR = 0.76, 95% CI: 0.54–1.08, p = 0.13, I2 = 29%). The risk of MACE was lower (OR = 0.84, 95% CI: 0.73–0.98, p = 0.02, I2 = 39%) in the 1-month DAPT compared with the >1-month DAPT. Only patients with stable CAD had lower risk of MACE with 1-month DAPT (OR = 0.81, 95% CI: 0.67–0.98, p = 0.03, I2 = 21%) compared with >1-month DAPT. Conclusion: This meta-analysis proved the non-inferiority of 1-month DAPT followed by aspirin or a P2Y12 receptor inhibitor compared with long-term DAPT in patients undergoing PCI with DES