ST-segment Elevation Myocardial Infarction in North African Women: Results From a Twenty-year Experience.

Background: Coronary artery disease remains the most common cause of morbidity and mortality in the general population. Several studies in developed countries have reported a gender-related difference in ST-segment elevation myocardial infarction (STEMI) in terms of risk factors, clinical presentation, delays in management, therapeutic modalities, and in-hospital as well as one-year outcomes. Data from non-developed countries about women with STEMI remain rare. We therefore aimed through this study to investigate the baseline characteristics of STEMI in Tunisian women compared to men and to determine the impact of gender difference on STEMI complications, in-hospital mortality, and one-year follow-up outcomes. Methods: All patients presenting to our center for STEMI between January 2001 and January 2021 were retrospectively enrolled in this analysis. Clinical features, therapeutic management, and in-hospital as well as one-year outcomes were compared between women and men. Predictive factors of in-hospital mortality in women were determined. Results: Out of 1670 STEMI hospitalizations, 359 (21.4%) were female. Compared to male, female had higher rates of hypertension (51.5% vs. 24.4%, p < 0.001), diabetes (50.1% vs. 32.2%, p < 0.001), and obesity (63.8% vs. 55%, p = 0.003). The clinical presentation was characterized by less prevalent inaugural chest pain (58.8% vs. 68.6%, p < 0.001). Atypical symptoms were significantly higher in women compared to men (55.2% vs. 5%, p<0.001). On admission, women had higher prevalence of anemia, renal failure, and hyperglycemia compared to men. Primary percutaneous coronary intervention (pPCI) was the reperfusion strategy of choice in 37.9% of women vs. 33.1% of men (p=0.02). Women were significantly less likely to receive thrombolysis (p = 0.004), with a significantly less prevalent successful thrombolysis (55.6% vs. 67.2%, p=0.013). In-hospital mortality was markedly higher in women compared to men (12.8% vs. 7.3%, p=0.001). Compared to surviving women (n = 313), those who died (n = 46) frequently had more diabetes and hypertension (65.2% vs. 47.9%, p= 0.02 and 67.4% vs. 49.2%, p = 0.02, respectively). New-onset atrial fibrillation, acute left heart failure, cardiogenic shock, ventricular tachycardia, and atrioventricular block markedly occurred in women who died (52.2% vs. 23.3%, p=<0.001; 17.4% vs. 1.9%, p < 0.001; 19.6% vs. 8.3%, p = 0.016; 15.2% vs. 1.6%, p < 0.001 and 34.8% vs. 10.2%, p < 0.001, respectively). Conclusion: Compared to men, Tunisian women presenting for STEMI had higher prevalence of risk factors and atypical symptoms. Women had more in-hospital complications and mortality.

Cardiac iron overload detection using longitudinal strain in asymptomatic children with beta thalassemia major.

Cardiomyopathy mediated by iron disposition in cardiomyocytes is a dreadful cause of morbidity and mortality in patients with beta thalassemia major (BTM). Conventional transthoracic echocardiography (TTE) parameters are preserved at late stages of cardiomyopathy induced by iron overload. Therefore, cardiac imaging modalities based on myocardial deformation such as strain imaging are used for early detection of cardiac iron overload. To demonstrate the contribution of longitudinal strain (LS) in early detection of cardiac iron overload in children with BTM. Sixty children (30 children with BTM and 30 healthy controls) were enrolled in this study. Conventional TTE study was performed in both patient and control groups. LV regional longitudinal strain (RLS) were determined and compared between the two study groups. Mean age was 10.4 ± 5 years in BTM group compared to 10.2 ± 5 years in control group (p = 0.876). Compared to control group, there was no significant difference in conventional TTE parameters except for indexed left atrium (LA) area and volume. LA was significantly larger in BTM children (27.59 ± 13.1 ml/m2 vs. 18.23 ± 4.33 ml/m2, p = 0.001). RLS was lower in anterior, septal and inferior walls in basal and middle segments of LV in BTM group while there was no significant difference in RLS in apical segment between the two groups (- 27.30 ± 5.1 vs.- 28.83 ± 4.33, p = 0.22). In asymptomatic BMT children with normal conventional TTE parameters, LS could be used for the detection of subclinical myocardial dysfunction.

Mid-term subclinical myocardial injury detection in patients who recovered from COVID-19 according to pulmonary lesion severity.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) may cause damage to the cardiovascular system during the acute phase of the infection. However, recent studies reported mid- to long-term subtle cardiac injuries after recovering from acute coronavirus disease 2019 (COVID-19). This study aimed to determine the relationship between the severity of chest computed tomography (CT) lesions and the persistence of subtle myocardial injuries at mid-term follow-up of patients who recovered from COVID-19 infection. Methods: All patients with COVID-19 were enrolled prospectively in this study. Sensitive troponin T (hsTnT) and chest CT scans were performed on all patients during the acute phase of COVID-19 infection. At the mid-term follow-up, conventional transthoracic echocardiograph and global longitudinal strain (GLS) of the left and right ventricles (LV and RV) were determined and compared between patients with chest CT scan lesions of < 50% (Group 1) and those with severe chest CT scan lesions of greater or equal to 50% (Group 2). Results: The mean age was 55 ± 14 years. Both LV GLS and RV GLS values were significantly decreased in group 2 (p = 0.013 and p = 0.011, respectively). LV GLS value of more than -18 was noted in 43% of all the patients, and an RV GLS value of more than -20 was observed in 48% of them. The group with severe chest CT scan lesions included more patients with reduced LV GLS and reduced RV GLS than the group with mild chest CT scan lesions [(G1:29 vs. G2:57%, p = 0.002) and (G1:36 vs. G2:60 %, p = 0.009), respectively]. Conclusion: Patients with severe chest CT scan lesions are more likely to develop subclinical myocardial damage. Transthoracic echocardiography (TTE) could be recommended in patients recovering from COVID-19 to detect subtle LV and RV lesions.

Design and Rationale of the National Tunisian Registry of Percutaneous Coronary Intervention: Protocol for a Prospective Multicenter Observational Study.

BACKGROUND: Coronary artery diseases remain the leading cause of death in the world. The management of this condition has improved remarkably in the recent years owing to the development of new technical tools and multicentric registries. OBJECTIVE: The aim of this study is to investigate the in-hospital and 1-year clinical outcomes of patients treated with percutaneous coronary intervention (PCI) in Tunisia. METHODS: We will conduct a prospective multicentric observational study with patients older than 18 years who underwent PCI between January 31, 2020 and June 30, 2020. The primary end point is the occurrence of a major adverse cardiovascular event, defined as cardiovascular death, myocardial infarction, cerebrovascular accident, or target vessel revascularization with either repeat PCI or coronary artery bypass grafting (CABG). The secondary end points are procedural success rate, stent thrombosis, and the rate of redo PCI/CABG for in-stent restenosis. RESULTS: In this study, the demographic profile and the general risk profile of Tunisian patients who underwent PCI and their end points will be analyzed. The complexity level of the procedures and the left main occlusion, bifurcation occlusion, and chronic total occlusion PCI will be analyzed, and immediate as well as long-term results will be determined. The National Tunisian Registry of PCI (NATURE-PCI) will be the first national multicentric registry of angioplasty in Africa. For this study, the institutional ethical committee approval was obtained (0223/2020). This trial consists of 97 cardiologists and 2498 patients who have undergone PCI with a 1-year follow-up period. Twenty-eight catheterization laboratories from both public (15 laboratories) and private (13 laboratories) sectors will enroll patients after receiving informed consent. Of the 2498 patients, 1897 (75.9%) are managed in the public sector and 601 (24.1%) are managed in the private sector. The COVID-19 pandemic started in Tunisia in March 2020; 719 patients (31.9%) were included before the COVID-19 pandemic and 1779 (60.1%) during the pandemic. The inclusion of patients has been finished, and we expect to publish the results by the end of 2022. CONCLUSIONS: This study would add data and provide a valuable opportunity for real-world clinical epidemiology and practice in the field of interventional cardiology in Tunisia with insights into the uptake of PCI in this limited-income region. TRIAL REGISTRATION: Clinicaltrials.gov NCT04219761; https://clinicaltrials.gov/ct2/show/NCT04219761. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/24595.

Clinical presentation, radiological findings and treatment options in Hughes-Stovin syndrome.

Hughes-Stovin syndrome is a rare disease characterized by thrombophlebitis associated with arterial or bronchial aneurysms. Even though it was described first in 1911, it is scarcely reported in the literature. Hughes-Stovin syndrome diagnosis is based on clinical manifestations as well as radiological findings. There are no validated criteria or specific laboratory findings to confirm the diagnosis. Computed tomography pulmonary angiography remains the gold standard for the diagnosis and follow-up of radiological findings, as they were recently described in a critical analysis of the largest cohort in the literature. The aim of this review is to draw attention to this rare but potentially fatal disease and to discuss its therapeutic options.

Long-term predictors of death among Tunisian patients presenting for non ST-elevation acute coronary syndrome.

BACKGROUND: Coronary artery disease is the leading cause of death in emerging countries. Contemporary data about clinical profile and prognosis in Tunisian patients presenting for non ST-elevation acute coronary syndrome (NSTE-ACS) are lacking. AIM: We sought to study the risk profile and 3-year mortality predictors in Tunisian patients presenting for NSTE-ACS in the contemporary setting. METHODS: In this single center study, data about all consecutive patients presenting to our center for NSTE-ACS from April 2014 to July 2016 were extracted and outcomes exhaustively updated. 3-year mortality predictors were determined by multivariable survival analysis. RESULTS: A total of 340 patients were included, of which 204 (61.8%) were male. Mean age was 63.6 ± 10.3 years. Prevalence of diabetes mellitus, hypertension and smoking was 57.3%, 62.4%, and 45.3%, respectively. In-hospital, 6, 12 and 36-month mortality rate was 2.3%, 3.2%, 7.1% and 15.2%, respectively. In multivariable survival analysis, independent predictors of death were age >75 (HR=5.45, 95% CI: 2.9-10.03, p<0.001), ST-segment deviation (HR=1.86, 95% CI: 1.04-3.33, p=0.036), anemia (HR=2.56, 95% CI: 1.41-4.67, p=0.002), left ventricular ejection fraction (LVEF) <40% (HR=3.5, 95% CI: 1.84-6.67, p<0.001) and a Global Registry of Acute Coronary Events (GRACE) score ≥140 (HR=2.38, 95% CI: 1.02-5.57, p=0.044). CONCLUSION: In Tunisian patients presenting for NSTE-ACS, long-term mortality was high. Advanced age, ST-segment deviation, anemia, LVEF <40% and a GRACE score ≥140 were independent long-term predictors of death.

Left atrial appendage closure with Watchman device: Insights from the first-ever Tunisian experience and six-year follow-up.

BACKGROUND: Stroke is a major complication of nonvalvular atrial fibrillation (AF). Despite its proven efficacy in stroke prevention, oral anticoagulation (OAC) is associated to a significant increase in bleeding complications. New techniques such as percutaneous left atrial appendage (LAA) closure were developed. AIM: To evaluate immediate, mid- and long-term outcomes after percutaneous LAA closure in Tunisian patients presenting with nonvalvular AF. METHODS AND RESULTS: Nineteen patients with nonvalvular AF were prospectively enrolled for percutaneous LAA closure between February 2013 and June 2014. The Watchman device was used in all LAA closure procedures. Clinical and echocardiographic follow-up were carried-out at 1, 6, 12 months and six years in all patients. Mean age was 68.4 ± 7.5 years. Thirteen patients were female, 16 had hypertension, 12 had diabetes mellitus and seven had a history of stroke or transient ischemic attack (TIA). Average CHA2DS2VASc (Congestive Heart Failure/Left Ventricular Dysfunction, Hypertension, Age≥75, Diabetes mellitus, Stroke/Transient Ischemic Attack/Thromboembolic event, Vascular disease,Age≥65, Sex category) score was 4.2 ± 1.5 and HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding tendency, Labile INR, Age≥65, Drugs) score was 3.5 ± 1. Ten patients had a history of severe bleeding. Procedural success was achieved in all patients. Pericardial effusion with tamponade was reported in one case. No post-procedural death was reported. Regular follow-up at 1, 6 and12 months then every year up to 6 years reported no stroke, no thromboembolic event, no Watchman device thrombosis and three cases of death caused by a respiratory problem and cancers. CONCLUSION: According to this study, LAA closure with Watchman device was safe and effective in preventing stroke in patients with nonvalvular AF and contra indication to OAC.

A Case of Behçet Disease Myocarditis Documented Using Cardiac Magnetic Resonance Imaging.

Acute myocarditis is extremely rare in patients with Behçet disease. Here we report a case of a 32-year-old man with a history of oral ulcerations who was admitted for fever and chest pain. On examination, he had bipolar ulcers with pseudofolliculitis and a positive pathergy test. Electrocardiogram and transthoracic echocardiography were normal. Cardiac magnetic resonance imaging revealed left ventricular inferior and lateral wall late gadolinium enhancement. A diagnosis of acute myocarditis revealing Behçet disease was made, and the patient was treated with colchicine and pulses of methylprednisolone, and cyclophosphamide. A 7-month follow-up magnetic resonance image showed a substantial decrease in the late gadolinium enhancement area.

Acute coronary syndrome: factors predicting smoking cessation.

BACKGROUND: Few randomized controlled trials have examined the efficacy time of smoking cessation in hospitalized patients with acute coronary syndrome, either during hospitalization or after discharge. AIMS: To assess smoking cessation rates at 24 weeks among patients with acute coronary syndrome. Group A had begun nicotine replacement therapy during hospitalization, and Group B after discharge. We also determined factors predicting success. METHODS: We conducted a randomized controlled trial in the Cardiology Department and Smoking Cessation Service at University Hospital of Monastir, Tunisia from January 2015 to June 2016. Participants were randomly assigned to the above 2 groups. The endpoint assessment was smoking abstinence at 24 weeks, defined as self-reported abstinence in the past week, confirmed by measured exhaled carbon monoxide (CO) ≤ 8 ppm. We analysed data by intention to treat. We used a binary logistic regression model to determine factors predicting abstinence. RESULTS: All participants were male and mean (standard deviation) age was 55 (11) years. At 24 weeks there was no significant difference in smoking cessation rate between the 2 groups: 54.5% [95% confidence interval (CI): 44.7-64.3%] in Group A and 45.5% (95% CI: 35.7-55.3%) in Group B (P = 0.81). High level of nicotine dependence [odds ratio (OR): 0.72; 95% CI: 0.54-0.96) and good compliance during follow-up (OR: 6.56; 95% CI: 2.07-20.78) were predictive factors for abstinence. CONCLUSIONS: Smoking cessation rate after acute coronary syndrome was high regardless of the start date. Good compliance during follow-up was the key predictive factor for success.

Machinability Study of Hardened 1045 Steel When Milling with Ceramic Cutting Inserts.

Intermittent machining using ceramic tools such as hard milling is a challenging task due to the severe mechanical shock that the inserts undergo during machining and the brittleness of ceramic inserts. This study investigates the machinability of hardened steel AISI 1045 during face milling using SiAlON and whisker (SiCW) based ceramic inserts. The main focus seeks to identify the effects of cutting parameters, milling configuration, edge preparation and work material hardness on machinability indicators such as resultant cutting force, power consumption and flank tool wear. The effects of these varying cutting conditions on performance characteristics were investigated using a Taguchi orthogonal array design L32 (21 44) and evaluated using ANOVA. Results indicate lower resultant cutting forces were recorded with honed edge inserts of SiAlON ceramic grade. In addition, a decrease in resultant cutting forces was associated with reduced feed rates and increased hardness. The feed rate and cutting speed were also identified as the greatest influencing factors in the amount of cutting power. The main wear mechanisms responsible for flank wear on the ceramic inserts are micro-scale abrasion and micro-chipping. Increased flank wear was observed at low cutting speed and high feed rates, while micro-chipping mostly ensued from the cyclic loading of the radial tool edge form, which is more susceptible to impact fragmentation. Thus, the use of tools with chamfered tool-edge preparation greatly improved observed wear values. Additional confirmation tests were also conducted to validate the results of the tests.

Prognostic value of hyperglycemia on-admission in diabetic versus non-diabetic patients presenting with ST-elevation myocardial infarction in Tunisia.

BACKGROUND: Hyperglycemia on-admission is a powerful predictor of adverse events in patients presenting for ST-elevation myocardial infarction (STEMI). AIM: In this study, we sought to determine the prognostic value of hyperglycemia on-admission in Tunisian patients presenting with STEMI according to their diabetic status. METHODS: Patients presenting to our center between January 1998 and September 2014 were enrolled. Hyperglycemia was defined as a glucose level ≥11mmol/L. In-hospital prognosis was studied in diabetic and non-diabetic patients. The predictive value for mortality of glycemia level on-admission was assessed by mean of the area under receiver operating characteristic (ROC) curve calculation. RESULTS: A total of 1289 patients were included. Mean age was 60.39±12.8years and 977 (77.3%) patients were male. Prevalence of diabetes mellitus was 70.2% and 15.2% in patients presenting with and without hyperglycemia, respectively (p<0.001). In univariate analysis, hyperglycemia was associated to in-hospital death in diabetic (OR: 8.85, 95% CI: 2.11-37.12, p<0.001) and non-diabetic patients (OR: 2.57, 95% CI: 1.39-4.74, p=0.002). In multivariate analysis, hyperglycemia was independently predictive of in-hospital death in diabetic patients (OR: 9.6, 95% CI: 2.18-42.22, p=0.003) but not in non-diabetic patients (OR: 1.93, 95% CI: 0.97-3.86, p=0.06). Area under ROC curve of glycemia as a predictor of in-hospital death was 0.792 in diabetic and 0.676 in non-diabetic patients. CONCLUSION: In patients presenting with STEMI, hyperglycemia was associated to hospital death in diabetic and non-diabetic patients in univariate analysis. In multivariate analysis, hyperglycemia was independently associated to in-hospital death in diabetic but not in non-diabetic patients.

Hughes-Stovin syndrome revealing the presence of Behçet's Disease.

BACKGROUND: Hughes-Stovin Syndrome (HSS) is a rare clinical disorder characterized by deep venous thrombosis and multiple pulmonary and/or bronchial aneurysms. Aneurysms in systemic circulation can also be seen. CASE PRESENTATION: We report the first case of HSS with aortic aneurysm in a 55-year-old man who initially presented with deep venous thrombosis. The diagnosis of HSS revealing Behçet's disease was made given the history of recurrent oral and genital ulcers. Treatment consisted of 3 daily pulses of methylprednisolone (1g) followed by oral prednisone (1mg/kg daily) and 6 monthly pulses of cyclophosphamide. Oral anticoagulation treatment was held 3 months and then was stopped with good outcome. CONCLUSION: Systemic aneurysms in Hughes Stovin is a worth knowing complication which may reveal Behçet's disease.

Clinical features and prognosis of infective endocarditis in children: Insights from a Tunisian multicentre registry.

BACKGROUND: Infective endocarditis (IE) is a rare condition in the paediatric setting. No data on the epidemiology and prognosis of IE in children are available from North African countries. AIM: To investigate the epidemiological profile and prognosis of IE in children in Tunisia. METHODS: All patients aged≤18 years presenting with IE in three Tunisian tertiary care centres between January 1997 and September 2013 were included. Clinical features and 30-day and 6-month mortality rates were studied. Factors predictive of death at 6-month follow-up were determined. RESULTS: A total of 73 patients were included in the present study. The mean age was 12±4.8 years; 35 (50.7%) patients were male. Rheumatic heart disease (RHD) was the underlying heart disease in 17 (23.3%) cases and IE occurred in a structurally normal heart in 36 (49.3%) cases. Staphylococcus species were isolated in 17 (23.3%) cases. Regarding IE localization, the mitral valve was involved in 28 (38.4%) cases and the aortic valve in 14 (19.2%) cases. Recourse to surgery was reported in 37 (50.7%) cases. Thirty-day and 6-month mortality rates were 13.6% and 19.2%, respectively. Heart failure on admission or during the hospital course, acute renal failure and neurological complications were significantly associated with death at 6-month follow-up in the univariate analysis and after adjustment for age and sex. CONCLUSIONS: In the Tunisian context, IE in children is still characterized by the high prevalence of RHD as an underlying heart disease. Short- and long-term mortality rates remain high. Heart failure, acute renal failure and neurological complications are significantly associated with death at 6-month follow-up.

Prevalence and prognostic significance of anemia in patients presenting for ST-elevation myocardial infarction in a Tunisian center.

BACKGROUND: Anemia on admission is a powerful predictor of major cardiovascular events in patients presenting for acute coronary syndromes. We sought to determine the prevalence and prognostic impact of anemia in patients presenting for ST-elevation myocardial infarction (STEMI). METHODS: We analyzed data from a Tunisian retrospective single center STEMI registry. Patients were enrolled between January 1998 and October 2014. Anemic and nonanemic patients were compared for clinical and prognostic features and according to four prespecified hemoglobin level subgroups. In patients with severe anemia, factors associated with in-hospital death were studied. RESULTS: A total of 1498 patients were enrolled. Mean age was 60.47 ± 12.7 years and prevalence of anemia was 36.6%. Anemic patients were more likely to be elderly, hypertensive, and diabetic in comparison to nonanemic patients. In-hospital mortality was significantly higher in anemic patients (14.9% vs. 5%, p < 0.001). Lower hemoglobin levels were significantly associated with a higher prevalence of heart failure on admission, cardiogenic shock, and in-hospital mortality (p < 0.001 for all). In univariate analysis, factors associated with in-hospital death in patients with severe anemia were hypertension (p = 0.044), heart failure on admission (p < 0.001), renal failure on admission (p < 0.001), and primary percutaneous coronary intervention (pPCI) use (p = 0.016). The absence of pPCI use was independently associated with in-hospital death in multivariate analysis (odds ratio = 2.22, 95% confidence interval: 1.07-4.76, p = 0.033). CONCLUSION: According to this study, anemic patients presenting for STEMI have a higher in-hospital mortality rate. The absence of pPCI use was independently associated with in-hospital death.

Risk profile and in-hospital prognosis in elderly patients presenting for acute ST-elevation myocardial infarction in the Tunisian context.

OBJECTIVES: Little is known about the risk profile and in-hospital prognosis of elderly patients presenting for ST-elevation myocardial infarction (STEMI) in Tunisia. We sought to determine in-hospital prognosis of elderly patients with STEMI in a Tunisian center. METHODS: The study was carried out on a retrospective registry enrolling 1403 patients presenting with STEMI in a Tunisian center between January 1998 and January 2013. Patients ≥75 years old were considered elderly. Risk factors and in-hospital prognosis were compared between elderly and younger patients, and then predictive factors of in-hospital death were determined in elderly patients. RESULTS: Out of the overall population, 211 (15%) were part of the elderly group. Compared to younger patients, elderly patients were more likely to have arterial hypertension but less likely to be smokers and obese. Thrombolysis was significantly less utilized in the elderly group (22.3% vs. 36.6% in the younger group, p<0.001), whereas the use primary percutaneous coronary intervention was comparable between the two sub-groups (24.2% vs. 28.8%, p=0.17). The incidence of in-hospital complications was higher in the elderly group, and so was the in-hospital mortality rate (14.2% vs. 8.1%, p=0.005). Heart failure on-admission, renal failure on-admission, and inotropic agents use were independently associated to in-hospital death in the elderly group. CONCLUSIONS: In the Tunisian context, elderly patients presenting with STEMI have higher prevalence of risk factors and a worse in-hospital course in comparison to younger patients. Clinical presentation on-admission has a strong impact on in-hospital prognosis.

PCSK9 polymorphism in a Tunisian cohort: identification of a new allele, L8, and association of allele L10 with reduced coronary heart disease risk.

The c.61_63dupCTG (L10) allele of rs72555377 polymorphism in PCSK9 has been reported to be associated with low-density lipoprotein-cholesterol (LDL-C) levels and with a decreased risk of coronary artery disease (CAD). We investigated the effect of two known alleles for rs72555377, L10 and L11, on the risk of CAD in a Tunisian cohort (218 patients diagnosed by angiography and 125 control subjects). Two subgroups of patients were defined by their level of stenosis: ≥50% for CAD and <50% for no-CAD. The genotypes were obtained by the size measurement of fluorescent-labeled PCR products. We identified a novel allele for the rs72555377 polymorphism: an in-frame deletion, c.61_63delCTG (L8). The frequency of the L10 allele was significantly higher in the no-CAD subgroup than in the CAD subgroup (0.210 vs 0.114, p = 0.045), and than in the subgroup of CAD patients presenting a stenosis ≥50% in two or three major coronary arteries (0.210 vs 0.125, p = 0.028). Multiple regression analysis showed that the L10 allele was significantly associated with a reduced risk of CAD (p = 0.049, OR = 0.51[0.26-1.00]), and with its reduced severity (p = 0.045, OR = 0.44[0.20-0.98]). The L10 allele is associated with a reduced risk and severity of CAD, seemingly independently of its LDL-lowering effect, suggesting a direct effect of PCSK9 on atherogenesis.

Effect of E670G Polymorphism in PCSK9 Gene on the Risk and Severity of Coronary Heart Disease and Ischemic Stroke in a Tunisian Cohort.

The association of E670G (rs505151) polymorphism in PCSK9 gene with an increased risk of coronary artery disease (CAD) and ischemic stroke (IS) was reported in previous studies. We investigated the effect of the E670G (rs505151) on the risk of CAD and IS in a Tunisian cohort. Genotyping of the PCSK9 E670G was performed using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) and then confirmed by direct sequencing. The frequency of the 670G allele was significantly higher in the CAD than in the no-CAD subgroup (0.132 vs. 0.068, p = 0.030). As expected, the incidence of E670G was significantly important in IS subgroup than control group (0.122 vs. 0.073, p = 0.032). Furthermore in CAD patients, the 670G carriers showed significantly increased plasma total cholesterol and LDL-cholesterol levels compared to E670 carriers (6.78 [6.47-7.00] vs. 4.92 [4.02-5.46] mmol/l, p < 0.0001 and 4.60 [4.00-5.04] vs. 3.00 [2.22-3.70] mmol/l p = 0.001, respectively). The risk and severity of CAD were significantly increased in 670G carriers between no-CAD subgroup and CAD patients presenting a stenosis ≥50 % in two or three major coronary arteries (0.068 vs. 0.198, p = 0.001, OR = 3.39 [1.55-7.37]). The E670G polymorphism of the PCSK9 gene is mainly associated with a increased risk and severity of CAD and IS in Tunisian cohort.

Surface Finish and Residual Stresses Induced by Orthogonal Dry Machining of AA7075-T651.

The surface finish was extensively studied in usual machining processes (turning, milling, and drilling). For these processes, the surface finish is strongly influenced by the cutting feed and the tool nose radius. However, a basic understanding of tool/surface finish interaction and residual stress generation has been lacking. This paper aims to investigate the surface finish and residual stresses under the orthogonal cutting since it can provide this information by avoiding the effect of the tool nose radius. The orthogonal machining of AA7075-T651 alloy through a series of cutting experiments was performed under dry conditions. Surface finish was studied using height and amplitude distribution roughness parameters. SEM and EDS were used to analyze surface damage and built-up edge (BUE) formation. An analysis of the surface topography showed that the surface roughness was sensitive to changes in cutting parameters. It was found that the formation of BUE and the interaction between the tool edge and the iron-rich intermetallic particles play a determinant role in controlling the surface finish during dry orthogonal machining of the AA7075-T651 alloy. Hoop stress was predominantly compressive on the surface and tended to be tensile with increased cutting speed. The reverse occurred for the surface axial stress. The smaller the cutting feed, the greater is the effect of cutting speed on both axial and hoop stresses. By controlling the cutting speed and feed, it is possible to generate a benchmark residual stress state and good surface finish using dry machining.