The role of septal perforators and "myocardial bridging effect" in atherosclerotic plaque distribution in the coronary artery disease

The distribution of atherosclerotic plaque burden in the human coronary arteries is not uniform. Plaques are located mostly in the left anterior descending artery (LAD), then in the right coronary artery (RCA), circumflex branch (LCx) and the left main coronary artery (LM) in a decreasing order of frequency. In the LAD and LCx, plaques tend to cluster within the proximal segment, while in the RCA their distribution is more uniform. Several factors have been involved in this phenomenon, particularly flow patterns in the left and right coronary artery. Nevertheless, it does not explain the difference in lesion frequency between the LAD and the LCx as these are both parts of the left coronary artery. Branching points are considered to be the risk points of atherosclerosis. In the LCx, the number of side branches is lower than in the LAD or RCA and there are no septal perforators with intramuscular courses like in the proximal third of the LAD and the posterior descending artery (PDA). We hypothesized that septal branches generate disturbed flow in the LAD and PDA in a similar fashion to the myocardial bridge (myocardial bridging effect). This coronary architecture determines the non-uniform plaque distribution in coronary arteries and LAD predisposition to plaque formation

PspF-binding domain PspA1-144 and the PspA·F complex: New insights into the coiled-coil-dependent regulation of AAA+ proteins.

Phage shock protein A (PspA) belongs to the highy conserved PspA/IM30 family and is a key component of the stress inducible Psp system in Escherichia coli. One of its central roles is the regulatory interaction with the transcriptional activator of this system, the σ54 enhancer binding protein PspF, a member of the AAA+ protein family. The PspA/F regulatory system has been intensively studied and serves as a paradigm for AAA+ enzyme regulation by trans-acting factors. However, the molecular mechanism of how exactly PspA controls the activity of PspF and hence σ54-dependent expression of the psp genes is still unclear. To approach this question, we identified the minimal PspF-interacting domain of PspA, solved its structure, determined its affinity to PspF and the dissociation kinetics, identified residues that are potentially important for PspF regulation and analyzed effects of their mutation on PspF in vivo and in vitro. Our data indicate that several characteristics of AAA+ regulation in the PspA·F complex resemble those of the AAA+ unfoldase ClpB, with both proteins being regulated by a structurally highly conserved coiled-coil domain. The convergent evolution of both regulatory domains points to a general mechanism to control AAA+ activity for divergent physiological tasks via coiled-coil domains

Predominant location of coronary artery atherosclerosis in the left anterior descending artery. The impact of septal perforators and the myocardial bridging effect

INTRODUCTION: Coronary artery atherosclerosis presents characteristic patterns of plaque distribution despite systemic exposure to risk factors. We hypothesized that local hemodynamic forces induced by the systolic compression of intramuscular septal perforators could be involved in atherosclerotic processes in the left anterior descending artery (LAD) adjacent to the septal perforators' origin. Therefore we studied the spatial distribution of atherosclerosis in coronary arteries, especially in relation to the septal perforators' origin. MATERIAL AND METHODS: 64-slice computed tomography angiography was performed in 309 consecutive patients (92 male and 217 female) with a mean age of 59.9 years. Spatial plaque distribution in the LAD was analyzed in relation to the septal perforators' origin. Additionally, plaque distribution throughout the coronary artery tree is discussed. RESULTS: The coronary calcium score (CCS) was positive in 164 patients (53.1%). In subjects with a CCS > 0, calcifications were more frequent in the LAD (n = 150, 91.5%) compared with the right coronary artery (RCA) (n = 94, 57.3%), circumflex branch (CX) (n = 76, 46.3%) or the left main stem (n = 42, 25.6%) (p < 0.001). Total CCS was higher in the LAD at 46.1 (IQR: 104.2) and RCA at 34.1 (IQR: 90.7) than in the CX at 16.8 (IQR: 61.3) (p = 0.007). In patients with calcifications restricted to a single vessel (n = 54), the most frequently affected artery was the LAD (n = 42, 77.8%). In patients with lesions limited to the LAD, the plaque was located mostly (n = 37, 88.1%) adjacent to the septal perforators' origin. CONCLUSIONS: We demonstrated that coronary calcifications are most frequently located in the LAD in proximity to the septal branch origin. A possible explanation for this phenomenon could be the dynamic compression of the tunneled septal branches, which may result in disturbed blood flow in the adjacent LAD segment (milking effect)

Risk-factors associated with extremely high cardiovascular risk of mid- and long-term mortality following myocardial infarction: An analysis of the Hyperlipidaemia Therapy in tERtiary Cardiological cEnTer (TERCET) Registry

Introduction: Risk-factor identification and risk stratification are prerequisites to the effective primary and secondary prevention of cardiovascular disease (CVD). Patients at the highest risk benefit the most from the intensive risk-factor reduction. However, high-risk patients’ group is heterogeneous, and it is increasingly recognised that there is an 'extreme-risk' category of patients who may require particularly close attention and intensive therapeutic approach. The aim of this study was to identify subgroups of patients at the highest risk of death following myocardial infarction (MI) that might be considered as those at extremely high CVD risk. Methods: We used data from 19,582 participants of the Hyperlipidaemia Therapy in tERtiary Cardiological cEnTer (TERCET) Registry (NCT03065543) of patients with ischaemic heart disease in Poland from 2006-present. Characteristics of 13,052 patients with chronic coronary syndromes (CCS) were compared with those of 4,295 patients with myocardial infarction (STEMI and 48 NSTEMI). Multivariable logistic regression with stepwise backward elimination was used to identify risk factors associated with mortality in the 12-36 months following the index hospitalisation. Results: The mortality rates were significantly higher in patients after MI than in patients with CCS. In the multivariable analysis, the risk factors most strongly associated with 12-month mortality in patients after MI were left ventricular ejection fraction (LVEF) lower than 35% (hazard ratio [HR] 3.83, 95% confidence interval [CI] 3.14-4.67), age >75 years (HR 1.91, 95%CI 1.55-2.35), multivessel coronary artery disease (HR 1.61, 95%CI 1.30-1.99), atrial fibrillation (HR 1.53, 95%CI 55 1.21-1.94) diabetes mellitus (HR 1.35, 95%CI 1.11-1.64) and increased LDL-C (HR per 1 mmol/l 56 1.09, 95%CI 1.01-1.19) or creatinine levels (HR per 10 µmol/L 1.04, 95% CI 1.04-1.05). The risk factors that influenced mortality after 24-36 months were consistent with those after 12 months, with additional low haemoglobin (20-25% risk increase per 1 mmol reduction) and chronic obstructive pulmonary disease (65% risk increase after 36 months). Conclusions: In our large, single-centre real-world analysis we identified the patients with the highest risk of death who could probably benefit the most from the most intensive therapy, and hence should be considered to be an 'extreme risk' population

Australian and New Zealand Pulmonary Rehabilitation Guidelines

Background and objective: The aim of the Pulmonary Rehabilitation Guidelines (Guidelines) is to provide evidence-based recommendations for the practice of pulmonary rehabilitation (PR) specific to Australian and New Zealand healthcare contexts. Methods: The Guideline methodology adhered to the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. Nine key questions were constructed in accordance with the PICO (Population, Intervention, Comparator, Outcome) format and reviewed by a COPD consumer group for appropriateness. Systematic reviews were undertaken for each question and recommendations made with the strength of each recommendation based on the GRADE (Gradings of Recommendations, Assessment, Development and Evaluation) criteria. The Guidelines were externally reviewed by a panel of experts. Results: The Guideline panel recommended that patients with mild-to-severe COPD should undergo PR to improve quality of life and exercise capacity and to reduce hospital admissions; that PR could be offered in hospital gyms, community centres or at home and could be provided irrespective of the availability of a structured education programme; that PR should be offered to patients with bronchiectasis, interstitial lung disease and pulmonary hypertension, with the latter in specialized centres. The Guideline panel was unable to make recommendations relating to PR programme length beyond 8 weeks, the optimal model for maintenance after PR, or the use of supplemental oxygen during exercise training. The strength of each recommendation and the quality of the evidence are presented in the summary. Conclusion: The Australian and New Zealand Pulmonary Rehabilitation Guidelines present an evaluation of the evidence for nine PICO questions, with recommendations to provide guidance for clinicians and policymakers

Global mortality and readmission rates following COPD exacerbation-related hospitalisation: a meta-analysis of 65 945 individual patients

\ua9 2024, European Respiratory Society. All rights reserved.Background Exacerbations of COPD (ECOPD) have a major impact on patients and healthcare systems across the world. Precise estimates of the global burden of ECOPD on mortality and hospital readmission are needed to inform policy makers and aid preventive strategies to mitigate this burden. The aims of the present study were to explore global in-hospital mortality, post-discharge mortality and hospital readmission rates after ECOPD-related hospitalisation using an individual patient data meta-analysis (IPDMA) design. Methods A systematic review was performed identifying studies that reported in-hospital mortality, postdischarge mortality and hospital readmission rates following ECOPD-related hospitalisation. Data analyses were conducted using a one-stage random-effects meta-analysis model. This study was conducted and reported in accordance with the PRISMA-IPD statement. Results Data of 65 945 individual patients with COPD were analysed. The pooled in-hospital mortality rate was 6.2%, pooled 30-, 90- and 365-day post-discharge mortality rates were 1.8%, 5.5% and 10.9%, respectively, and pooled 30-, 90- and 365-day hospital readmission rates were 7.1%, 12.6% and 32.1%, respectively, with noticeable variability between studies and countries. Strongest predictors of mortality and hospital readmission included noninvasive mechanical ventilation and a history of two or more ECOPD-related hospitalisation

The influence of fuel contamination on operating characteristics of Common Rail injectors

Współczesne samochody z silnikami Diesla zasilanymi układami Common Rail są chętnie wybierane przez użytkowników. Cechuje je duża moc i elastyczność, niskie spalanie oraz spełnianie ekologicznych norm emisji. Jednak niewielu użytkowników jest świadomych jak istotna jest jakość paliwa użytego do zasilania silnika z układem Common Rail. Kompleksowa regeneracja układu wtryskowego CR wraz z oczyszczeniem obiegu niskiego oraz wysokiego ciśnienia paliwa może przekroczyć rynkową wartość samochodu kilkuletniego. W sytuacji takiej oszczędności płynące ze stosowania paliwa słabej jakości są pozorne. W artykule przedstawiono badania wpływu zanieczyszczenia paliwa na charakterystykę pracy wtryskiwaczy Common Rail.Modern cars with diesel engines powered by Common Rail systems are willingly chosen by users. They are characterized by high power and flexibility, fuel efficiency, fulfilling the ecological emission standards. However, very few users are aware of how important is the quality of the fuel used to power the engine with Common Rail injection system. Comprehensive regeneration of CR injection system, including cleaning of the high and low fuel pressure cycle may exceed the market value of several years car. In this situation savings deriving from the use of poor quality fuels are apparent. The article presents a study on the impact of fuel contamination on the operating characteristics of Common Rail injectors

Thermoresistive Thin Film Flow Sensor

Some technological aspects and basic parameters of nickel thin film gas flow sensors are presented. Thermal conditions of sensors are described by the mechanisms of heat transfer. Typical characteristics measured during the sensor operation are given

Analysis of possibility of the high-duty cast iron using for production of diesel forcers

There is given the analysis of the possibility of change of aluminium piston alloys by high-duty cast iron with globular or vermicular form of graphite