RESUMO
Background: Coronary artery disease (CAD) is the leading cause of cardiovascular death globally, and the most severe form of CAD, ST-elevation myocardial infarction (STEMI), needs immediate treatment. This study aimed to report patient characteristics and the causes of door-to-balloon time (D2BT) delays in STEMI patients admitted to Tehran Heart Center with a D2BT exceeding 90 minutes. Methods: This cross-sectional study was conducted at Tehran Heart Center, Iran, from March 20th, 2020, through March 20th, 2022. Variables consisted of age, sex, diabetes mellitus, hypertension, dyslipidemia, smoking, opium, family history of CAD, in-hospital mortality, primary percutaneous coronary intervention results, culprit vessels, causes of delays, the ejection fraction, triglycerides, and low and high-density lipoprotein levels. Results: The study population was composed of 363 patients (272 males [74.9]) at a mean (SD) age of 60±11.47 years. The leading causes of D2BT delays were the catheterization lab used in 95 patients (26.2) and misdiagnosis in 90 (24.8). Other causes were ST-elevation less than 2 mm in electrocardiograms in 50 patients (13.8) and referral from other hospitals in 40 (11.0). Conclusion: The catheterization lab in use and misdiagnosis were the leading causes of D2BT delays. We recommend that high-volume centers allocate an additional catheterization lab with an on-call cardiologist. Improved resident training and supervision in hospitals with many residents are also necessary.
RESUMO
High-resolution microscopy investigations on ancient ceramics recommend the complex progression of crystalline phases in an antique object via the sintering process. Based on materials-science point of view, sintering is not a routinely reaction in all crystalline phases with the same crystallographic pattern, but also is a transition pathway. Sintering depends on the processing of raw materials via the manufacturing process. Five samples are chosen for this analytical approach from two different periods from Tappeh Zaghe, Iran (5100 millennium BC). A multimicroscopical approach was carried out by means of polarized light microscopy, environmental scanning electron microscopy, and atomic force microscopy. Crystalline phases were determined by X-ray diffraction and refined after Rietveld method. The observation of the behavior of phase-interphase boundaries of a crystalline part in the nano area suggests that the partial sintering is the point at which the mineral began to be decomposed, and the conditions of the occurrences of this phenomenon depend on crystallographic properties.