Chronic Total Occlusion-Angioplasty with Antegrade Approach: A two-Year Experience in “Modarres Hospital”, A Tertiary University Hospital, Tehran, Iran

Introduction: New techniques for the percutaneous treatment of coronary chronic total occlusions (CTO) have had a high success rate since a few years ago, so the interest for this treatment has been increasing these days.Methods: The current observational study was performed in Modarres hospital as a tertiary referral center. All the patients with documented stable angina who had failed to response to full guideline-mediated medical therapy, referred to our hospital, were candidates for coronary angiography. Antegrade strategy was applied for all these patients. The length of the lesion, the fluoroscopy time of the CTO angioplasty, consumed contrast volume, the number of guide wires used, whether a corsair or tornus micro-catheter was used or not, and the success rate of the angioplasty were documented for further analysis.Results: A total of 47 patients with documented stable angina were finally included. The median age was 59 (45-78) and 70.2% were male. The mean length of the lesion was 34.0 ± 1.1 .The mean fluoroscopy time and contrast volume were 57.9 ± 3.2 minutes and 525.9 ± 20.9 mL, respectively. In average, 2.2 guide wires were used. Corsair and tornus micro-catheters were applied in 30 (63.8%) and 5 (10.6%) of the cases, respectively. Seven complications (all including coronary dissection) occurred. In-hospital major adverse cardiac events (MACE) rate was 10.6%, all of which were non-Q wave myocardial infarction. The success rate was 85.1%. The higher number of used wires, use of corsair, and tornus micro-catheter were not significantly concordant with success rate (P-value > 0.05); in addition, longer lesion was not concordant with unsuccessfulness rate (P-value > 0.05).Conclusions: Patient selection for CTO-angioplasty should be performed more carefully. Patients’ quality of life and risk of probable procedural complications and future cardiac events should be assessed to decide the best treatment approach. Radiation exposure, contrast consumption and fluoroscopy time are recommended to be monitored during the procedure and thresholds should be defined to enhance safety and efficacy

Usability Evaluation of Laboratory and Radiology Information Systems Integrated into a Hospital Information System

This study was conducted to evaluate the usability of widely used laboratory and radiology information systems. Three usability experts independently evaluated the user interfaces of Laboratory and Radiology Information Systems using heuristic evaluation method. They applied Nielsen’s heuristics to identify and classify usability problems and Nielsen’s severity rating to judge their severity. Overall, 116 unique heuristic violations were identified as usability problems. In terms of severity, 67 % of problems were rated as major and catastrophic. Among 10 heuristics, “consistency and standards” was violated most frequently. Moreover, mean severity of problems concerning “error prevention” and “help and documentation” heuristics was higher than of the others. Despite widespread use of specific healthcare information systems, they suffer from usability problems. Improving the usability of systems by following existing design standards and principles from the early phased of system development life cycle is recommended. Especially, it is recommended that the designers design systems that inhibit the initiation of erroneous actions and provide sufficient guidance to users

The effect of proton-pump inhibitors on development of arrhythmia and hypomagnesaemia after off-pump coronary artery bypass surgery

Introduction: Long-term use of proton-pump inhibitors (PPI) can result in hypomagnesaemia and arrhythmia.The aim of this study was to compare the effect of PPI and histamine 2-receptor antagonists (H2RA) on the incidence of hypomagnesaemia and arrhythmia in patients following off-pump coronary artery bypass surgery (CABG).Method: In this randomized-controlled clinical trial 290 patients admitted ICU after off-pump CABG were randomly divided into two groups of H2RA (n=145) and PPI (n=145).For patients in the H2RA group, 50 mg intravenous ranitidine was prescribed every 8hrs after during the nothing by mouth (NPO) period followed by 40mg famotidine tablet after starting the oral regimen (PO). The PPI group received 40 mg pantozol IV injections every 12 hrs during the NPO period and 40mg pantozol tablets once daily after becoming PO.The patients were investigated for development of hypomagnesaemia and associated arrhythmia.Results: In total 271 patients with the mean age of 59.3±10 yrs completed the study (female/male=32.8%). Hypomagnesaemia occurred in 60.1% of the patients; 76 (56.7%) in the H2RA group and 87 (63.5%) in the PPI group (P=0.245) whereas arrhythmia had a prevalence of 12 (9.6%) and 15 (11.1%), respectively (P=0.690). The mean time of occurrence of hypomagnesaemia and arrhythmia were 1.75±1.08 and 3.0±0.9 days after the operation in the H2RA group and 1.47±0.7 and 2.9±1.5 days in the PPI group, respectively (P=0.111 and P=0.897).Conclusion: Our study revealed that the short-term use of PPIs does not result in higher rates of hypomagnesaemia and associated arrhythmia in comparison to H2RAs after off-pump CABG

An innovative method to assess clinical reasoning skills: Clinical reasoning tests in the second national medical science Olympiad in Iran

BACKGROUND: Clinical reasoning plays a major role in the ability of doctors to make a diagnosis and reach treatment decisions. This paper describes the use of four clinical reasoning tests in the second National Medical Science Olympiad in Iran: key features (KF), script concordance (SCT), clinical reasoning problems (CRP) and comprehensive integrative puzzles (CIP). The purpose of the study was to design a multi instrument for multiple roles approach in clinical reasoning field based on the theoretical framework, KF was used to measure data gathering, CRP was used to measure hypothesis formation, SCT and CIP were used to measure hypothesis evaluation and investigating the combined use of these tests in the Olympiad. A bank of clinical reasoning test items was developed for emergency medicine by a scientific expert committee representing all the medical schools in the country. These items were pretested by a reference group and the results were analyzed to select items that could be omitted. Then 135 top-ranked medical students from 45 medical universities in Iran participated in the clinical domain of the Olympiad. The reliability of each test was calculated by Cronbach's alpha. Item difficulty and the correlation between each item and the total score were measured. The correlation between the students' final grade and each of the clinical reasoning tests was calculated, as was the correlation between final grades and another measure of knowledge, i.e., the students' grade point average. RESULTS: The combined reliability for all four clinical reasoning tests was 0.91. Of the four clinical reasoning tests we compared, reliability was highest for CIP (0.91). The reliability was 0.83 for KF, 0.78 for SCT and 0.71 for CRP. Most of the tests had an acceptable item difficulty level between 0.2 and 0.8. The correlation between the score for each item and the total test score for each of the four tests was positive. The correlations between scores for each test and total score were highest for KF and CIP. The correlation between scores for each test and grade point average was low to intermediate for all four of the tests. CONCLUSION: The combination of these four clinical reasoning tests is a reliable evaluation tool that can be implemented to assess clinical reasoning skills in talented undergraduate medical students, however these data may not generalizable to whole medical students population. The CIP and KF tests showed the greatest potential to measure clinical reasoning skills. Grade point averages did not necessarily predict performance in the clinical domain of the national competitive examination for medical school students

Optimum Design of FGX-CNT-Reinforced Reddy Pipes Conveying Fluid Subjected to Moving Load

The harmony search algorithm is applied to the optimum designs of functionally graded (FG)-carbon nanotubes (CNTs)-reinforced pipes conveying fluid which are subjected to a moving load. The structure is modeled by the Reddy cylindrical shell theory, and the motion equations are derived by Hamilton's principle. The dynamic displacement of the system is derived based on the differential quadrature method (DQM). Moreover, the length, thickness, diameter, velocity, and acceleration of the load, the temperature and velocity of the fluid, and the volume fraction of CNT are considered for the design variables. The results illustrate that the optimum diameter of the pipe is decreased by increasing the volume percentage of CNTs. In addition, by increasing the moving load velocity and acceleration, the FS is decreased

Graph theoretical defense mechanisms against false data injection attacks in smart grids

Abstract This paper addresses false data injection, which is one of the most significant security challenges in smart grids. Having an accurately estimated state is of great importance for maintaining a stable running condition of smart grids. To preserve the accuracy of the estimated state, bad data detection (BDD) mechanisms are utilized to remove erroneous measurements due to meter failures or outsider attacks. In this paper we use a graph-theoretical formulation for false data injection attacks in smart grids and propose defense mechanisms to mitigating this type of attacks. To this end we discuss characteristics of a typical smart grid graph such as planarity. Then we propose three different approaches for finding optimal protected meters set: a fast and efficient heuristic algorithm that works well in practice, an approximation algorithm that provides guarantee for the quality of the protected set, and an exact algorithm that find the optimal solution. Our extensive simulation results show that our algorithms outperform similar existing solutions in terms of different performance metrics

Incidence and Associated Factors of No-reflow Phenomenon in STEMI Patients Treated with Primary PCI

Background: Primary percutaneous angioplasty is a modality of choice to restore reperfusion in infarct related artery now. No-reflow phenomenon is a complication of this modality that increase mortality and morbidity of patients. Assessment of its associated and predictor factors may be useful to its prevention. Methods: All patients with ST elevation myocardial infarction (STEMI) who treated with primary percutaneous angioplasty during 30 months were enrolled to the study.Then patients with and without no-reflow phenomenon assigned to two groups and statistical analysis was performed. Results: Twenty one cases of no-reflow were found in total 263 cases of primary PCI (7.9%). Mean age and prevalence of risk factors such as diabetes mellitus, smoking, hypertension and hyperlipidemia wasn't different in two groups. No- reflow was observed more frequently in females (P<0.01). Mean symptom to balloon time was longer in No-reflow group (P <0.01). Patients with no- reflow phenomenon have more cardiogenic shock, less predischarge ejection fraction, more inhaspital mortality, longer stent length, more LAD as infarct related artery and more use of thrombectomy( p valu

A Combined Approach to Severe Multi-Organ Atherosclerosis

Severe coronary artery disease often coexists with peripheral vascular atherosclerosis. The assessment of the supra-aortic circulation is, therefore, of clinical relevance. We herein describe a case of coronary artery disease treated with surgical revascularization using the internal mammary artery and thereafter the progressive atherosclerotic disease of the native coronary arteries as well as the left subclavian and left renal arteries. We also describe and discuss the clinical presentation, the diagnostic procedures, and the therapeutic approach with respect to the percutaneous transluminal angioplasty of the subclavian, renal, and right coronary arteries

Immediate Results and Six-Month Clinical Outcome after Percutaneous Coronary Intervention in Patients with Prior Coronary Artery Bypass Surgery

Background: Redo coronary artery bypass grafting surgery (CABG) is associated with a higher risk of mortality than the first operation. However, the impact of percutaneous coronary intervention (PCI) on the outcome in such patients is currently unclear. We evaluated the in-hospital and six-month clinical outcomes of post-CABG patients who underwent PCI in our center.Methods: Between April 2008 and July 2009, 71 post-CABG patients (16 women and 55 men) underwent 110 stent implantations (74% drug-eluting stents) for 89 lesions. Sixty percent of the PCI procedures were performed on the native coronary arteries, 32% on graft arteries, and 8% on both types of vessels. Major adverse cardiac events (MACE) were recorded in hospital and at six months’ follow-up.Results: The procedural success rate was 93%, and the in-hospital MACE rate was 5.6 % (1 death, 3 myocardial infarctions). At 6 months, the incidence of MACE was 5.6% (no death or myocardial infarction, but 4 target lesion revascularizations) and 4 (5.6 %) in-stent restenoses. There was no statistically significant difference in the comparison of MACE between the patients treated in either native arteries or in the grafts (15% vs.12%, p value = 0.8). According to the univariate analysis, hypertension and the use of the bare metal stent vs. the drug-eluting stent were the significant predictors of MACE, whereas the multivariate analysis showed that only hypertension (OR = 3.7, 95% CI 3.4-4, p value < 0.048) was the independent predictor of MACE. The mean of the left ventricular ejection fraction had no effect on the incidence of MACE (p value = 0.9). The multivariate analysis showed hypertension (p value < 0.048) and the use of the bare metal stent (p value < 0.018) were the independent predictors of MACE. The chronic total occlusion (CTO) (p value < 0.01) was the independent predictor of the success rate. The prevalence of diabetes had no impact on the incidence of MACE according to the univariate analysis (p value = 0.9). Our multivariate analysis showed that hypertension and the use of the bare metal stent were the independent predictors of MACE and that chronic total occlusion was the independent predictor of the procedural failure rate.Conclusion: PCI is preferable to redo CABG for post-CABG patients. The independent predictors of MACE were hypertension and bare metal stents