Art and Science

This study sought to define the sex-difference in trabecular and cortical bone parameters in Vietnamese individuals. The study involved 1404 women and 864 men aged between 20 and 86 years who were recruited from Ho Chi Minh City, Vietnam. Trabecular and cortical volumetric BMD were measured at the proximal tibia and proximal radius at 4%, 38%, and 66% points, using a peripheral quantitative computed tomography XCT2000 (Stratec, Germany). Polar strength strain index was estimated from cortical bone parameters. Changes in bone parameters were assessed by the multiple linear regression model. Among individuals aged 20-39 years, women had significantly lower peak trabecular BMD at both the radius (40%) and tibia (16%) than men, but the age-related reduction in trabecular BMD were similar between two sexes. For cortical BMD, peak values in women and men were comparable, but the age-related diminution was greater in women than men. At any age, polar strength strain index in women was lowe...

Background. Unfractionated heparin has been the standard anticoagulant used immediately after mechanical heart valve replacement (MHVR). The purpose of this study was to assess a postoperative anticoagulation protocol with low-molecular-weight heparin (LMWH) immediately after MHVR without the use of unfractionated heparin or anti-factor Xa monitoring. Methods. We performed a prospective, single-center, observational study of 1,063 consecutive patients undergoing elective MHVR with postoperative LMWH anticoagulation treatment. The exclusion criteria were as follows: renal failure, intraaortic balloon counterpulsation, critical perioperative state, or a recent neurologic event. The postoperative anticoagulation protocol used subcutaneous enoxaparin as a bridging anticoagulant treatment beginning on the first postoperative day and continuing until vitamin K antagonist treatment was fully effective. Patients were followed for 6 weeks. The primary endpoints were the incidence of thromboembolic or major bleeding events. Results. Eleven (1%) thromboembolic events occurred. Ten of these events were transient or permanent strokes. Major bleeding events occurred in 44 patients (4.1%), 7 of which were observed before the enoxaparin treatment period. At the time of discharge, 570 patients (53.6%) were no longer receiving LMWH treatment due to achieving the target international normalized ratio. The mean length of hospital stay was 8.5 ± 2.9 days. There were no deaths during the 6-week follow-up period. Conclusions. In our highly selected population, after MHVR, postoperative anticoagulation using LMWH is associated with a low rate of thromboembolic and major bleeding events. This large observational study demonstrates that the use of LMWH as an anticoagulant is effective and safe after MHVR.

Objectives: To review our experience with sutureless aortic valve replacement (AVR) in the setting of concomitant mitral valve (MV) surgery and discuss the technical considerations. Methods: Between January 2012 and March 2013, 10 patients underwent sutureless AVR with the Perceval prosthesis in the setting of concomitant mitral disease. Five patients underwent MV repair, 4 underwent MV replacement, and 1 had a previously implanted mechanical mitral prosthesis. Results: The median age was 79 years and 7 patients (70%) were male. Median logistic EuroSCORE II was 6.2%. All valves were successfully implanted with no 30-day mortality. There was no residual aortic paravalvular leak. Two patients had from third-degree atrioventricular block requiring permanent pacemaker implantation. At a mean follow-up of 8 AE 4 months (range, 2-16 months), the overall survival was 80% with 2 nonÀvalve-related deaths and the mean transaortic gradient and aortic valve area had improved to 11.1 AE 4.6 mm Hg and 1.5 AE 0.3 cm 2 , respectively. There was no evidence of mitral dysfunction in any patient. Conclusions: In our experience, sutureless AVR in the setting of concomitant mitral surgery is a feasible and reproducible procedure. Elderly patients undergoing multiple valve surgery present a higher operative risk, therefore extending the indication for sutureless AVR to patients with concomitant mitral disease could greatly benefit this specific population. (

Background: Obesity is suggested to reduce postoperative bleeding in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) but perioperative hemostasis variations have not been studied. Therefore, we investigated the effects of severe obesity (body mass index [BMI] ≥35 kg/m 2 ) on chest tube output (CTO) and hemostasis in patients undergoing cardiac surgery with CPB. Materials and Methods: We prospectively investigated 2799 consecutive patients who underwent coronary and/ or valve surgery using CPB between 2008 and 2012. 204 patients (7.3%) presented a severe obesity. Results: In the severe obesity group, the 6-h and 24-h CTO were significantly reduced by -21.8% and -14.8% respectively (P b 0.0001) compared with the control group. A significant reduction of the mean number of red blood cell units transfused at 24 h was observed in the severe obesity groups (P = 0.01). On admission to the intensive care unit, a significant increase of platelet count (+ 9.2%; P b 0.0001), fibrinogen level (+12.2%; P b 0.0001) and prothrombin time (+4.1%; P b 0.01) and a significant decrease of the activated partial thromboplastin time (-4.2%; P b 0.01) were observed in the severe obesity group compared with the control group. In multivariate analysis, severe obesity was significantly associated to a decreased risk of excessive bleeding (24-h CTO N 90th percentile; Odds ratio: 0.37, 95% CI: 0.17 to 0.82). No significant differences were observed regarding postoperative thromboembolic events between the two groups. Conclusions: Severe obesity is associated with a prothrombotic postoperative state that leads to a reduction of postoperative blood loss in patients undergoing cardiac surgery with CPB.

In a fertilizer plant, the steam boiler is the mostimportant component. In order to keep the plant operating in the effective mode, the boiler efficiency must be observed continuously by several operators. When the trend of the boiler efficiency is going down, they may adjust the controlling parameters of the boiler to increase its efficiency. Since manual operation usually leads to unexpectedly mistakes and hurts the efficiency of the system, we build an information system that plays the role of the operators in observing the boiler and adjusting the controlling parameters to stabilize the boiler efficiency. In this paper, we first introduce the architecture of the information system. We then present how to apply K-means and Fuzzy C-means algorithms to derive a knowledge base from the historical operational dataof the boiler. Next, recurrent fuzzy neural network is employed to build a boiler simulator forevaluating which tuple of input values is the best optimal and then automatica...

The purpose of this study was to assess the impact on hospital mortality and morbidity of extensive myocardial revascularization, using arterial grafts in patients undergoing isolated coronary artery bypass grafting (CABG). Our prospective perioperative database was used to define two groups of patients who underwent isolated CABG with cardiopulmonary bypass, based on the years in which the operation was performed: Group A (2000-2003; 898 patients) and Group B (2009-2012; 1249 patients). The baseline and operative characteristics and outcomes were compared. Several significant changes in perioperative variables were observed. Group B included higher percentages of patients aged over 80 years (+58.1%), with diabetes (+32.0%) and with a history of percutaneous coronary intervention (+24.9%). The mean EuroSCORE II was significantly increased from 2.5 ± 4.4% in Group A to 3.2 ± 5.7% in Group B (P= 0.001). The mean number of distal anastomoses was significantly increased over time (total...

Background: Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation is associated with significant mortality and morbidity. The objective of this study was to determine pre-and postoperative risk factors associated with the occurrence of RVF after LVAD implantation. Methods: This retrospective study included 68 patients who received LVADs between 2010 and 2018 either for bridge to transplant (40 patients, 58.8%) or bridge to destination therapy (28 patients, 41.2%). RVF after LVAD implantation was defined according to the INTERMACS classification. The primary endpoint was the occurrence of RVF. The secondary endpoints were hospital mortality and morbidity and long-term survival. The majority of patients (61.8%) had an INTERMACS profile 1 (36.8%) or 2 (25.0%). The LVAD was implanted either by sternotomy (37 patients, 54.4%) or thoracotomy (31 patients, 45.6%). RVF after LVAD implantation was observed in 32 patients (47.1%). In univariate analysis, an elevated serum glutamic oxaloacetic transaminase (SGOT) (P=0.028) and a high preoperative vasoactive inotropic score (VIS) (P=0.028) were significantly associated with an increased risk of RVF, whereas the implantation of LVAD through a thoracotomy approach was associated with a significant reduction in this risk (P=0.006). The multivariate analysis demonstrated that only the thoracotomy approach was significantly associated with decreased risk of RVF (odds ratio =0.33, 95% confidence interval: 0.17-0.96; P=0.042). Hospital mortality was 53.1% and 5.6% in the RVF and control groups, respectively (P<0.0001). The incidence of stroke and postoperative acute renal failure were significantly increased in the RVF group compared with the control group. The survival after LVAD implantation was 33.5%±9.0% and 85.4%±6.0% at 1 year in the RVF and control groups, respectively (P<0.0001). Conclusions: LVAD implantation by thoracotomy significantly reduced the risk of postoperative RVF. This surgical approach should, therefore, be favored.

The main spindle bearing assembly (MSBA) plays an important role in the quality and service life of CNC machine tools and industrial equipment. The MSBA is usually evaluated based on the allowable wear or the stiffness independently combined with the vibration characteristics. Therefore, it is very important to determine the service life of MSBA when the wear reaches the allowable value, and the stiffness is reduced to the allowable value. This paper studies the simultaneous relationship of wear, stiffness, and vibration characteristics of MSBA in a CNC lathe. The results show that the service life of MSBA is different when evaluated based on each criterion (wear or stiffness). The stiffness of the MSBA is reduced to the allowable limit [J] = 200 N/mm with a Root Mean Square (RMS) value of about 5.75 mm/s 2 . The wear of the MSBA reaches the allowable limit [d a ] = 5 mm with an RMS value of about 4.5 mm/s 2 . The life of MSBA calculated according to the stiffness criterion is about 1.18 times higher than that calculated based on the wear criterion. The average life of MSBA with standard lubrication according to the wear criterion reaches ∼15,799 h and RMS reaches ∼2.4508 mm/s 2 .

We reported the case of a 56-year-old male with tetralogy of Fallot associated with an aneurysm of the aortic root and severe aortic insufficiency. Repair of the aortic aneurysm along with a complete tetralogy repair was performed. Cases of uncorrected tetralogy of Fallot (TOF) in adults are rare. We present a case of a 56-year-old patient with unrepaired TOF, pulmonary valvular stenosis without major aorto-pulmonary collaterals (MAPCAs), and an aortic root aneurysm. The surgical management of this rare abnormality is reviewed.

Background. This study was conducted to identify preoperative predictors of postoperative atrial fibrillation (POAF) after isolated coronary artery bypass grafting (CABG) by using a Bayesian analysis that included information from prior studies. Methods. We performed a prospective observational study from October 2008 to December 2013 of 1,481 patients who underwent isolated CABG with cardiopulmonary bypass and had no history of AF. Bayesian analysis was used to study the preoperative risks factors for POAF. Results. The POAF incidence was 21%. Multivariate analysis identified the following independent predictors of POAF after CABG: high CHA 2 DS 2 -VASc (Congestive heart failure, Hypertension [blood pressure >140/90 mm Hg or treated hypertension on medication], Age ‡75 years, Diabetes mellitus, prior Stroke or transient ischemic attack or thromboembolism, vascular disease, Age 65 to 74 years, Sex category [female sex]) score (odds ratio [OR], 1.23; 95% credible interval [CI], 1.14 to 1.33 per 1-point increment, probability (Pr) [OR > 1] [ 1), severe obesity with a body mass index of 35 kg/m 2 or higher (OR, 1.28; 95% CI, 1.12 to 1.45; Pr [OR > 1] [ 1), preoperative b-blocker use (OR, 1.12; 95% CI, 1.06 to 1.20; Pr [OR > 1] [ 1), preoperative antiplatelet therapy (OR, 1.75; 95% CI, 1.14 to 2.79, Pr [OR > 1] [ 1), and renal insufficiency with a creatinine clearance of less than 60 mL/min (OR, 1.34; 95% CI, 1.03 to 1.74; Pr [OR > 1] [ 1). Conclusions. This prospective Bayesian analysis identified five independent preoperative predictors of POAF after isolated CABG with cardiopulmonary bypass: CHA 2 DS 2 -VASc score, severe obesity, preoperative b-

Objective: Left ventricle (LV) transmural gradient in mitochondrial respiration has been recently reported. However, to date, the physiological mechanisms involved in the lower endocardium mitochondrial respiration chain capacity still remain to be determined. Since, nitric oxide (NO) synthase expression in the heart has spatial heterogeneity and might impair mitochondrial function, we investigated a potential association between LV transmural NO and mitochondrial function gradient. Methods: Maximal oxidative capacity (V Max ) and relative contributions of the respiratory chain complexes II, III, IV (V Succ ) and IV (V TMPD ), mitochondrial content (citrate synthase activity), coupling, NO (electron paramagnetic resonance), and reactive oxygen species (ROS) production (H 2 O 2 and dihydroethidium (DHE) staining) were determined in rat sub-endocardium (Endo) and sub-epicardium (Epi). Further, the effect of a direct NO donor (MAHMA NONOate) on maximal mitochondrial respiratory rates (V max ) was determined. Results: Mitochondrial respiratory chain activities were reduced in the Endo compared with the Epi (-16.92%; P = 0.04 for V max and -18.73%; P = 0.02, for V succ , respectively). NO production was two-fold higher in the Endo compared with the Epi (P = 0.002) and interestingly, increasing NO concentration reduced V max . Mitochondrial H 2 O 2 and LV ROS productions were significantly increased in Endo compared to Epi, citrate synthase activity and mitochondrial coupling being similar in the two layers. Conclusions: LV mitochondrial respiration transmural gradient is likely related to NO and possibly ROS increased production in the sub-endocardium.