Mustafa Burak Sayhan

Iodinated contrast agents are widely used in diagnostic and interventional procedures and constitute an essential component of modern clinical practice [1–3]. Nevertheless, contrast-associated acut...

Background and Objectives: Non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is a heterogeneous emergency condition in which early diagnostic assessment may be challenging. YKL-40 is associated with vascular inflammation and extracellular matrix remodeling, but its age-independent diagnostic relevance in NSTE-ACS remains uncertain. We evaluated the association and discriminatory performance of serum YKL-40 in patients with adjudicated NSTE-ACS versus non-ACS chest-pain controls; subtype discrimination, revascularization, and correlations with routinely measured inflammatory indices were explored as secondary outcomes. Materials and Methods: This prospective, single-center observational study included 88 adults presenting to the emergency department with chest pain between December 2024 and March 2025. Sixty had adjudicated NSTE-ACS, including 32 with non-ST-segment elevation myocardial infarction and 28 with unstable angina, while 28 constituted the non-ACS control group. Serum YKL-40 was measured at presentation using an enzyme-linked immunosorbent assay. Patient–control discrimination was assessed using receiver operating characteristic analysis, logistic regression, and bootstrap internal validation. Exploratory sensitivity analyses included Firth penalized regression and comparisons restricted to overlapping age ranges. Results: In the unadjusted analysis, serum YKL-40 concentrations were higher in the NSTE-ACS group than in non-ACS controls (median, 832.1 vs. 552.6 ng/L; p = 0.002). Log-transformed YKL-40 yielded an area under the curve of 0.709 (95% CI, 0.599–0.819; p < 0.001) and was associated with NSTE-ACS status (OR per 1-standard-deviation increase, 1.89; 95% CI, 1.15–3.12; p = 0.013). After adjustment for age, the association was attenuated and no longer statistically significant (OR, 1.58; 95% CI, 0.92–2.71; p = 0.100). Models additionally accounting for renal function and cardiovascular risk factors, together with analyses restricted to overlapping age ranges, yielded consistent findings. YKL-40 showed limited discrimination between NSTEMI and unstable angina (AUC, 0.527; 95% CI, 0.376–0.678), was not significantly associated with revascularization (OR, 1.76; 95% CI, 0.86–3.59; p = 0.120; AUC, 0.614), and was not significantly correlated with C-reactive protein, white blood cell count, or the neutrophil-to-lymphocyte ratio. Conclusions: The unadjusted association between YKL-40 and NSTE-ACS was attenuated after accounting for age and other baseline differences. These findings do not establish an age-independent diagnostic role or support the routine diagnostic use of YKL-40 in NSTE-ACS.

Background/Objectives: Early identification of adult major trauma patients at high risk of death remains challenging in the emergency department. Lactate reflects tissue hypoperfusion, whereas ionized calcium contributes to coagulation and cardiovascular function. This study evaluated the prognostic performance of the lactate-to-ionized calcium ratio (LiCa) for in-hospital mortality and compared it with established trauma scores. Methods: This single-center retrospective cohort study included adults with major trauma, defined as an Injury Severity Score (ISS) ≥ 16, who presented to a tertiary emergency department between May 2021 and April 2023. Demographic, clinical, laboratory, and outcome data were obtained from electronic records. LiCa was calculated as lactate divided by ionized calcium using the initial arterial blood gas sample obtained within 30 min of emergency department arrival. Factors associated with mortality were examined using multivariable logistic regression. Discrimination was assessed using receiver operating characteristic analysis and compared across LiCa, ISS, and Trauma and Injury Severity Score (TRISS) models. Results: A total of 236 patients were analyzed. In-hospital mortality occurred in 49 patients (20.8%). LiCa remained associated with in-hospital mortality after adjustment (adjusted odds ratio, 1.42; 95% confidence interval, 1.23–1.62; p < 0.001). LiCa showed good discrimination in this cohort, with an area under the curve of 0.93 (95% confidence interval, 0.88–0.97), compared with 0.94 for both TRISS 1995 and TRISS 2010 and 0.85 for ISS. At an exploratory threshold of ≥12.59, LiCa yielded 82% sensitivity, 94% specificity, a positive likelihood ratio of 12.72, and a negative likelihood ratio of 0.20. Conclusions: LiCa was independently associated with in-hospital mortality and showed good discrimination within this single-center retrospective cohort. As a rapidly available blood gas-derived measure, LiCa may provide exploratory adjunctive prognostic information at presentation, but it should not be interpreted as a replacement for validated trauma scoring systems. Prospective multicenter validation is needed before routine clinical use.

Background and Objectives: To identify factors associated with hospital admission decisions among hematologic patients presenting to the emergency department (ED) and to evaluate the incremental contribution of clinical, laboratory, and process-related variables using a hierarchical modeling framework. Materials and Methods: Single-center, retrospective observational cohort study conducted between January 2016 and December 2018. Adult patients for whom a hematology consultation was requested at ED presentation were included. Hierarchical block modeling was used as a sequential multivariable logistic regression approach in which clinical, laboratory, and process-related variables were entered in separate blocks. Process-related variables were defined as ED workflow-related factors, including mode of arrival, timing of presentation, and transfusion requirement. Model performance was assessed using the area under the receiver operating characteristic curve (AUC), Hosmer–Lemeshow goodness-of-fit test, calibration plot, calibration slope/intercept, and nested bootstrap internal validation. Results: Of 428 patients included, 297 (69.4%) were hospitalized. In the updated final model, impaired mental status (aOR 2.682; 95% CI 1.393–5.161), ambulance arrival (aOR 2.607; 95% CI 1.532–4.434), body temperature (aOR 1.399 per °C; 95% CI 1.049–1.866), respiratory rate (aOR 1.105 per breath/min; 95% CI 1.019–1.197), and heart rate (aOR 1.023 per bpm; 95% CI 1.007–1.040) were independently associated with hospital admission. Transfusion requirement showed an inverse association with admission (aOR 0.397; 95% CI 0.244–0.644), whereas platelet count showed the same direction of association but did not reach statistical significance in the updated final model. The final model demonstrated moderate apparent discrimination (AUC 0.771; 95% CI 0.725–0.818), with no statistically significant lack of fit on the Hosmer–Lemeshow test (p = 0.188). After nested bootstrap internal validation, the optimism-corrected AUC was 0.729. Conclusions: In hematologic patients presenting to the ED, admission decisions were associated mainly with acute physiological instability—particularly impaired mental status and abnormal vital signs—rather than by age or sex. These findings should be interpreted as exploratory associations with real-world disposition decisions, not as a validated tool for predicting objective outcomes such as mortality, ICU transfer, or 30-day adverse events.

Clozapine is a second-generation antipsychotic with proven efficacy in treatment-resistant schizophrenia patients; however, it requires careful monitoring due to its serious side effects. While its most well-known side effect is agranulocytosis, gastrointestinal hypomotility is a less recognized but potentially fatal complication. This article presents a case of a 37-year-old male patient weighing 73 kg who had been taking 300 mg of clozapine daily for two years and developed megacolon and stercoral colitis as a result of clozapine-induced gastrointestinal hypomotility. The patient presented to the emergency department after three months of constipation complaints; abdominal computed tomography revealed marked colonic dilatation and fecal impaction. Clozapine treatment was discontinued, conservative treatment was administered, and clinical improvement was achieved. The patient was discharged completely recovered without the need for surgical intervention. This case highlights the rare but serious gastrointestinal side effects of clozapine and demonstrates that early diagnosis and appropriate treatment can prevent mortality. It is clinically critical to inquire about constipation symptoms in patients using clozapine and to perform early evaluation for megacolon.

Background/Objectives: Transient ischemic attack (TIA) is a neurological emergency associated with a substantial early risk of ischemic stroke, yet its diagnosis remains clinically challenging because objective biomarkers are limited. Glycoprotein VI (GPVI), a platelet collagen receptor involved in platelet activation and thrombus formation, may reflect prothrombotic activity in cerebrovascular ischemia. This study aimed to evaluate the diagnostic assessment and short-term risk stratification value of serum GPVI levels in patients presenting to the emergency department with suspected TIA. Methods: This prospective observational cohort study included 85 adult patients with transient focal neurological symptoms suggestive of TIA. Patients were classified according to the Precise Diagnostic Score (PREDISC), and early stroke risk was assessed using the ABCD2 score. Serum GPVI levels were measured using enzyme-linked immunosorbent assay. Patients were followed for cerebrovascular events at 2 and 7 days. Associations between GPVI levels, clinical scores, and early outcomes were analyzed, and diagnostic performance was assessed using receiver operating characteristic analysis. Results: Serum GPVI levels differed significantly across PREDISC categories and increased from the “TIA unlikely” group to the “TIA very likely” group (p < 0.001). GPVI levels were also higher in patients with ABCD2 scores ≥4 than in those with lower scores (p < 0.001). GPVI showed positive correlations with both PREDISCs (Spearman’s r = 0.682, p = 0.001) and ABCD2 scores (Spearman’s r = 0.469, p = 0.001). All early cerebrovascular events occurred in the high-risk ABCD2 group. Patients who experienced cerebrovascular events had higher baseline GPVI levels, with a small-to-moderate effect size for 2-day outcomes (r = 0.22) and a moderate effect size for 7-day outcomes (r = 0.36). ROC analysis demonstrated discriminative performance for identifying patients classified as “TIA very likely” according to the PREDISC system, with an area under the curve of 0.821 (95% CI: 0.71–0.91). Conclusions: Serum GPVI levels were associated with PREDISC-based clinical TIA likelihood, higher ABCD2-defined risk categories, and early cerebrovascular events in patients with suspected TIA. These findings suggest that GPVI may have a potential complementary role within structured emergency department–based diagnostic assessment and short-term risk stratification frameworks, pending validation in larger independent cohorts. However, because of the exploratory single-center design, modest sample size, limited number of outcome events, and absence of external validation, these findings should be interpreted as hypothesis-generating and require confirmation in larger multicenter studies.