We address the problem of representing context-specific causal models based on both observational and experimental data collected under general (e.g. hard or soft) interventions by introducing a new family of context-specific conditional independence models called CStrees. This family is defined via a novel factorization criterion that allows for a generalization of the factorization property defining general interventional directed acyclic graph (DAG) models. We derive a graphical characterization of model equivalence for observational CStrees that extends the Verma and Pearl criterion for DAGs. This characterization is then extended to CStree models under general, context-specific interventions. To obtain these results, we formalize a notion of context-specific intervention that can be incorporated into concise graphical representations of CStree models. We relate CStrees to other context-specific models, showing that the families of DAGs, CStrees, labelled DAGs, and staged trees form a strict chain of inclusions. We then present an algorithm for learning CStrees from a combination of observational and interventional data where the intervention targets are assumed to be unknown with hard or soft and possibly context-specific effects. The algorithm, evaluated on simulated and real data, performs well in the recovery of context-specific dependence structure as well as context-specific interventional perturbations.
Objectives: To evaluate the impact of Primary Percutaneous Coronary Intervention (PCI) on Left Ventricular Function Recovery (LVFR) in patients with Acute Myocardial Infarction (AMI), with a specific focus on myocardial work efficiency, microvascular resistance, and long-term cardiac outcomes. Methodology: A total of 150 patients diagnosed with STEMI and treated with Primary PCI were included. Left Ventricular Ejection Fraction (LVEF) was assessed at baseline and again at six months post-PCI. Statistical analyses, including paired t-tests and chi-square tests, were conducted using SPSS version 26.0. Results: The mean baseline LVEF was 48.5% (range: 32%-65%), which improved significantly to 53.3% (range: 35%-70%) post-PCI, with an average increase of 7.2% (p < 0.05). The overall PCI success rate was 70%, with a significant age-wise variation: 85% in the 30-50 years group, 68% in the 51-65 years group, and 50% in patients aged 66 years and older (p = 0.02). Microvascular obstruction (MVO) was identified in 28% of patients and was significantly associated with a lower degree of LVEF improvement (p = 0.03). Younger patients demonstrated better recovery, with 76% of those aged 30-50 achieving at least a 10% LVEF improvement, compared to 50% in the 66+ group (p = 0.01). Conclusion: Primary PCI significantly enhances LVFR in AMI patients, particularly among younger individuals. Microvascular obstruction is a key factor impeding optimal recovery, underscoring the need for targeted therapeutic interventions. Future research should explore pharmacologic strategies and advanced imaging techniques to further improve outcomes.
We investigate the mixing properties of a model of reversible Markov chains in random environment, which notably contains the simple random walk on the superposition of a deterministic graph and a second graph whose vertex set has been permuted uniformly at random. It generalizes in particular a result of Hermon, Sly and Sousi, who proved the cutoff phenomenon at entropic time for the simple random walk on a graph with an added uniform matching. Under mild assumptions on the base Markov chains, we prove that with high probability the resulting chain exhibits the cutoff phenomenon at entropic time log n/h, h being some constant related to the entropy of the chain. We note that the results presented here are the consequence of a work conducted for a more general model that does not assume reversibility, which will be the object of a companion paper. Thus, most of our proofs do not actually require reversibility, which constitutes an important technical contribution. Finally, our argument relies on a novel concentration result for "low-degree" functions on the symmetric group, established specifically for our purpose but which could be of independent interest.
In recent years, several studies have been made in which atmospheric and oceanic data were used to decompose horizontal velocity statistics into a rotational component, associated with vertical vorticity, and a divergent component, associated with horizontal divergence. The decomposition methods rely on the assumption of statistical isotropy. In this paper, the full anisotropic equations relating the rotational, divergent and the rotational-divergent components of the second order velocity structure function tensor to the longitudinal, transverse and longitudinal-transverse components are formulated and solved analytically.
Introduction Early stent thrombosis (ST) (≤30 days) following primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) remains a rare but serious complication. Despite advances in stent technology and antithrombotic therapy, this condition continues to be associated with high morbidity and mortality, particularly in resource-limited settings where local data are scarce. Purpose The purpose of this study is to evaluate the clinical characteristics, procedural factors, and in-hospital outcomes of patients with early stent thrombosis and to compare these findings with matched controls without stent thrombosis in a tertiary care cardiac center in Peshawar, Pakistan. Materials and methods This retrospective observational study included adult patients undergoing primary PCI who developed acute stent thrombosis (AST) (≤24 hours) or subacute stent thrombosis (24 hours to 30 days) during the same hospitalization. Data were collected from medical records, catheterization laboratory reports, and electronic hospital systems using a structured questionnaire. SPSS version 27.0 (IBM Corp., Armonk, NY) was used for statistical analysis, with comparisons made between cases and matched controls. Results A total of 80 patients with early stent thrombosis and 160 matched controls were analyzed. The majority were men (62/80, 77.5%). Common baseline cardiovascular risk factors included diabetes mellitus (28/80, 35%), hypertension (42/80, 52.5%), dyslipidemia (34/80, 42.5%), smoking (26/80, 32.5%), and prior coronary artery disease (12/80, 15%). Acute stent thrombosis occurred predominantly within 24 hours post-PCI (16/80, 20%). Procedural characteristics, including stent type, vascular access, and adjunctive therapies, were largely similar between sexes. Repeat PCI was the primary management strategy (62/80, 77.5%), and while most patients survived to discharge, a subset experienced serious in-hospital complications: heart failure (18/80, 22.5%), recurrent ischemia (10/80, 12.5%), arrhythmias (12/80, 15%), acute kidney injury (8/80, 10%), or bleeding events (6/80, 7.5%). Procedural factors associated with early stent thrombosis included high thrombus burden, suboptimal stent expansion, overlapping stents, and reduced post-procedural thrombolysis in myocardial infarction (TIMI) flow. Conclusion Early stent thrombosis after primary PCI remains an uncommon but potentially life-threatening complication with substantial in-hospital morbidity. Timely recognition and prompt intervention, primarily through repeat PCI, are essential to improve outcomes. These findings highlight the need for larger, multicenter studies to identify modifiable patient- and procedure-related risk factors, particularly in local populations, to enhance prevention and management strategies for early stent thrombosis.
