[Surgical treatment for type Stanford A aortic dissection with Kommerell's diverticulum].

Objective: To examine the outcomes of surgical treatment in patients of type Stanford A aortic dissection with Kommerell's diverticulum. Methods: From January 2009 to August 2017, patients of type Stanford A aortic dissection with Kommerell's diverticulum who underwent the Sun procedure were enrolled. Patient demographic, preoperative, intraoperative, early morbidity and mortality data were collected from medical and electronic patient records. Clinical follow-up data, including late morbidity and mortality, were obtained by telephone interview with the patient. Results: A total of 13 patients (11 males and 2 females; mean age 47 years) were included. The mean maximum diameter of Kommerell's diverticulum was (21.8±7.7) mm. The Kommerell's diverticulum was repaired by direct suture of the orifice in 3 patients, ligation of the aberrant right subclavian artery in 9 patients, and suture and ligation in 1 patient, respectively. No perioperative death occurred. One patient underwent a reexploration for bleeding. There were 2 late deaths: unknown reason in 1 patient and septic shock secondary to renal abscess in 1 patient. Reintervention was performed in one patient for a persistent type Ⅱ endoleak. Conclusions: The Sun procedure with femoral artery cannulation for cardiopulmonary bypass, unilateral carotid artery cannulation for selective cerebral perfusion and ligation of aberrant right subclavian artery on the right side of the trachea is an appropriate therapeutic strategy for patients of type Stanford A aortic dissection with Kommerell's diverticulum.

[Long-term outcome comparison of ostial/shaft lesions in unprotected left main coronary artery treated by PCI or CABG].

Objective: To evaluate long-term clinical outcomes of consecutive patients treated with coronary artery bypass grafting (CABG) and percutaneous coronary intervention(PCI) with drug-eluting stents(DES) for ostial/shaft lesions in unprotected left main coronary artery(ULMCA). Method: A total of 259 patients with isolated ostial/midshaft lesions in unprotected left main coronary artery were enrolled consecutively who received DES implantation or underwent CABG between January 2003 and July 2009 in Beijing Anzhen Hospital. The endpoints of the study were death, repeat revascularization, myocardial infarction (MI) and stroke. Time to the primary endpoint was evaluated according to the Kaplan-Meier method, and the log-rank test was applied to compare the incidence of the endpoint. Adjusted risks for adverse outcomes were compared by multivariate Cox proportional hazard regression analyses. Results: A total of 259 patients were included, including 149 in PCI group and 110 in CABG group. And 193(74.5%) cases were males.The age was (61.4±9.8) years old. The median follow-up was 10.1 years (interquartile range 8.3 to 11.2 years) in the overall patients. There were no significant difference for the incidence of death [37.0% vs. 43.1% ，P=0.143] , MI [34.0% vs. 19.4% ，P=0.866], stroke [6.4% vs. 11.7% ， P=0.732], repeart revascularization [33.6% vs. 39.9% ，P=0.522] between PCI group and CABG group before multivariate adjusting，according to the incidence calculated with Kaplan-Meier. After adjusting covariates such as age, left ventricular ejection fraction（LVEF） and serum creatine with multivariate Cox hazard regression model, there was still no significant difference between the two groups. Conclusions: PCI with DES is as effective and safe as CABG in patients with left main ostium/shaft lesion during a median follow-up of 10.1 years.

Strong anisotropic nodal lines in the TiBe family.

Using first-principles calculations and k·p model analysis, we find that Dirac nodal lines (DNLs) exist in low energy band structures of real materials of the body-centered cubic TiBe family. The nodal lines are protected by mirror reflection symmetries of the systems. The anisotropic electronic state interaction around the Fermi level produces a strong anisotropic quasi-square shape nodal line in the systems. Moreover, all the systems demonstrate drumhead surface states spanning a large energy window showing their potential in terms of high temperature superconductivity. The slight gap induced by spin-orbit coupling (SOC) indicates that materials of the TiBe family are promising candidates for future experimental studies on nontrivial topological semimetals.

Identification of Ground Intrusion inUnderground StructuresBased on Distributed Structural Vibration Detected by Ultra-Weak FBG Sensing Technology.

It is challenging for engineers to timely identify illegal ground intrusions in underground systems such as subways. In order toprevent the catastrophic collapse of subway tunnels from intrusion events, this paper investigated the capability of detecting the ground intrusion of underground structures based on dynamic measurement of distributed fiber optic sensing. For an actual subway tunnel monitored by the ultra-weak fiber optic Bragg grating (FBG)sensing fiber with a spatial resolution of five meters, a simulated experiment of the ground intrusion along the selected path was designed and implemented, in which a hydraulic excavator was chosen to exert intrusion perturbations with different strengths and modes at five selected intrusion sites. For each intrusion place, the distributed vibration responses of sensing fibers mounted on the tunnel wall and the track bed were detected to identify the occurrence and characteristics of the intrusion event simulated by the discrete and continuous pulses of the excavator under two loading postures. By checking the on-site records of critical moments in the intrusion process, the proposed detection approach based on distributed structural vibration responses for the ground intrusion can detect the occurrence of intrusion events, locate the intrusion ground area, and distinguish intrusion strength and typical perturbation modes.

Two Dimensional Antiferromagnetic Chern Insulator: NiRuCl6.

Density functional theory (DFT) and Berry curvature calculations show that quantum anomalous Hall effect (QAHE) can be realized in two-dimensional(2D) antiferromagnetic (AFM) NiRuCl6. The results indicate that NiRuCl6 behaves as an AFM Chern insulator and its spin-polarized electronic structure and strong spin-orbit coupling (SOC) are responsible for the QAHE. By tuning SOC, we found that the topological property of NiRuCl6 arises from its energy band inversion. Considering the compatibility between the AFM and insulators, AFM Chern insulator provides a new way to archive high temperature QAHE in experiments due to its different magnetic coupling mechanism from that of ferromagnetic (FM) Chern insulator.

[Reoperation for residual aneurysm of coronary anastomosis after Bentall procedure].

Objective: To introduce a new operative method for residual aneurysm of coronary anastomosis after Bentall procedure. Methods: Between March 2011 and December 2012, six patients in Beijing Anzhen Hospital with residual aneurysm of coronary anastomosis (CT showed goldfish eye sign at the openings of coronary) after Bentall procedure underwent the operation of concentric circular patch procedure under cardiopulmonary bypass. Femoral artery, right atrium and upper right pulmonary artery cannulation were used for cardiopulmonary bypass, and the artificial vessel was transected after cardiac arrest. A concentric circular patch was pruned, whose outside diameter was slightly larger than the aneurysm and the inside diameter was equal to the openings of coronary. The outer edge of the patch was anastomosed to the outer edge of the aneurysm (opening of artificial vessel in primary surgery) with 4-0 prolene. The inner edge of the patch was anastomosed to the openings of coronary with 5-0 prolene. Results: All patients had clinical recovery. Postoperative CT demonstrated the disappearance of residual aneurysm during follow-up (the goldfish eye sign disappeared). Conclusion: The concentric circular patch procedure is a feasible treatment for residual aneurysm of coronary anastomosis.

[Surgical treatment of aortic dissection with lower extremity ischemia].

Objective: To explore the clinical outcome of the surgical treatment for aortic dissection with lower extremity ischemia. Methods: Between March 2009 and April 2013, 14 patients with type A aortic dissection and lower extremity ischemia underwent Sun's procedure in Beijing Anzhen Hospital. Ascending aorta-iliac artery bypass, ascending aorta-femoral artery bypass, femoral-femoral artery bypass and axillary -femoral artery bypass were performed on some severe patients at the same time. Results: Two death occurred, and the others were improved or recovered from symptoms. Follow-up was complete with an average time of 24 months and no aortic relevant complications occurred. Conclusion: As for patients with type A aortic dissection and lower extremity ischemia, simultaneous radical femoral artery bypass procedure is effective in improving their survival rate and quality of life.

[Experience of Sun's procedure for chronic type B dissection with aortic arch involvement].

Objective: To study the surgical treatment of chronic type B dissection with aortic arch involvement using Sun's procedure. Methods: Between February 2009 and December 2015, 29 patients [20 males, 9 females, with a mean age of (41±12) years, range 24-64 years] with type B dissection with aortic arch involvement underwent Sun's procedure. Sixteen patient had a history of hypertension. Marfan syndrome was observed in 9 cases, coronary artery disease in 3 cases, mitral regurgitation in 3 patients, cerebrovascular disease in one patient. Twenty-two patients suffered proximal aortic arch disease, 4 cases experienced history of aortic root procedure and 2 subjects had history of pregnancy. Four patients had aortic arch malformation. Results: One case suffered from massive cerebral infarction after surgery and died in another hospital. Concomitant procedures included mitral valve replacement in 3 cases, coronary artery bypass grafting in 3 patients, reconstruction of the right aberrant subclavian artery in one patient. Ventilator support exceeding 24 hours obseved in 2 patients. One of them recieved continuous renal replacement therapy and recovered before discharge. Spinal cord injury was obseved in one case, brain infarction in one patient and pericardial drainage in one case. Two patients required tracheotomy. During 12-94 (43±23) months' follow-up, thoracoabdominal aortic replacment was performed in 4 patients, thoracic endovascular aortic repair (TEVAR) in 2 subjects and repair of perivalvular leakage in one patient. Conclusions: Sun's procedure obtained satisfactory results in patients with chronic type B dissection with aortic arch involvement. Concomitant repair of proximal aortic arch lesions and distal type B dissection can be adopted using Sun's procedure.

[Progress and challenge of Stanford type A aortic dissection in China].

In recent 20 years, the rapid development of acute Stanford type A aortic dissection in China has been mainly due to three aspects: (1) the refined classification of aortic dissection based on Stanford classification, (2) right axillary artery canal and selective cerebral perfusion technology become basic cardiopulmonary bypass strategy for Stanford type A aortic dissection, and (3) total aortic arch replacement and descending aortic stent graft surgery (Sun's surgery) become the standard treatment of Stanford type A aortic dissection. However, there are still many problems in the diagnosis and treatment of aortic dissection in China, such as: (1) unstandardized, lack of comprehensive guidelines of aortic dissection, (2) immature, perioperative organ protection and intraoperative blood protection technology remains a big flaw, and (3) it takes a long time to get patient prepared for surgery. In conclusion, as to the issue of the management of acute Stanford type A aortic dissection, there will be a long way for Chinese doctors to go. Peers should pay more attention to this problem and take more efforts, so that the outcome of acute Stanford type A aortic dissection surgical patients can be improved.

[Progress of problems related to the reconstruction of aortic arch in acute type A aortic dissection].

Aortic arch reconstruction is one of the most challenging operations in aortic surgery. Anatomical abnormalities of the aortic arch, including bovine aortic arch, aberrant right subclavian artery, and single vertebral artery have direct impact on the choice of surgical procedures and methods of brain protection.The risk of aortic arch reconstruction and the difficulty of operation, it is possible to avoid the injury of patients by strictly grasping the indication of operation. Intraoperative arterial cannulation and brain protection strategies are directly related to the success of the operation. This article makes a brief review of the above problems in the reconstruction of the aortic arch, hoping to be helpful to the cardiovascular surgeon.

Prediction of two planar carbon allotropes with large meshes.

Two novel two-dimensional (2D) carbon allotropes named C(y) and C(z) with large meshes are predicted based on first-principles calculations. Their formation energies are lower than that of graphdiyne, which was recently synthesized in an experiment. Molecular dynamics simulations indicate that C(y) and C(z) are stable even when the temperature is over 1000 K. The calculated Poisson's ratios of C(y) and C(z) show their anisotropic mechanical properties. The electronic structure calculations indicate that C(y) is a metal, while C(z) behaves as a semiconductor. Moreover, C(z) shows conductive anisotropy suggesting its potential in nanoelectronic devices. Meanwhile, their well-defined mesh structures are suitable for molecular sieves.

Two-dimensional tricycle arsenene with a direct band gap.

Based on a comprehensive investigation including ab initio phonon and finite-temperature molecular dynamics calculations, we find that two-dimensional tricycle-shaped arsenene (T-As) is robust and even stable under high temperature. T-As is energetically comparable to previously reported chair-shaped arsenene (C-As) and more stable than stirrup-shaped arsenene (S-As). In contrast to C-As and S-As, the monolayer T-As is a direct band gap semiconductor with an energy gap of 1.377 eV. Our results indicate that the electronic structure of T-As can be effectively modulated by stacking, strain, and patterning, which shows great potential of T-As in future nano-electronics. Moreover, by absorbing H or F atoms on the surface of T-As along a specific direction, nanoribbons with desired edge type and even width can be obtained, which is suitable for the fabrication of nano-devices.

[Application of evoked potentials monitoring in total thoracoabdominal aorta aneurysm repair].

OBJECTIVE: To evaluate the application value of evoked potentials (EP) monitoring in patients undergoing aorta-iliac bypass for total thoracoabdominal aorta aneurysm repair (tTAAAR). METHODS: A prospective study, with a total of 31 patients undergoing tTAAAR and intraoperative EP monitoring from June 2014 to April 2015 was carried out. The results of intraoperative evoked potentials, clinical outcomes and follow-up data of patients were collected for further evaluation. RESULTS: The EP wave disappeared [motor evoked potentials for (55.6±18.1) min, somatosensory evoked potentials for (50.3±18.7) min] after proximal descending aorta being clamped, and gradually recovered after the segment arteries of spine cord were reconstructed. The EP wave was restored to normal level at the end of operation in all the cases. The somatosensory evoked potentials remained unchanged in 2 cases (false negative). One case died after operation. No spinal cord injury occurred. The median follow-up after operation was 10 months (5-14 months). There was no delayed neurological deficit. CONCLUSION: EP provided an on-line monitoring of the condition of spinal cord function, which become an intraoperative protocol to avoid the irreversible injury of spinal cord.

[A prediction model for severe postoperative hypoxemia after surgery for Standford type A aortic dissection].

OBJECTIVE: To study the risk factors of severe postoperative hypoxemia after surgery for Standford type A aortic dissection and establish a prediction model. METHODS: Data of 411 consecutive patients from January 2014 to April 2015, who underwent surgery for Standford type A aortic dissection in the department of cardiovascular surgery of Beijing Anzhen Hospital, were retrospectively analyzed. All the cases were divided into two groups according to the appearance of severe postoperative hypoxemia. All the data about potential risk factors was put into the database and analyzed by logistic regression. The prediction model was then established upon acquired independent risk factors. Discrimination and calibration of the prediction model were assessed with ROC curve and Hosmer and Lemeshow goodness of fit test. RESULTS: The perioperative in-hospital mortality was 6.57%(27/411). Severe postoperative hypoxemia (PaO2/FiO2≤100 mmHg) happened in 69 cases within 48 hours after procedures, with an incidence rate of 17.1%. The logistic regression demonstrated that body mass index (BMI), age, preoperative serum myoglobin, preoperative serum creatinine, preoperative serumalanine aminotransferase, the time of cardiopulmonary bypass, re-exploration within 48 hours after procedures were the independent risk factors for severe postoperative hypoxemia. The prediction model was then established based on these independent risk factors. The area under ROC curve of the model was 0.785, and the P value in Hosmer and Lemeshow goodness of fit test was 0.625. CONCLUSION: The logsitic model built in this study succeeded to predict the incidence of severe postoperative hypoxemia after surgery for Standford type A aortic dissection, and it could meet the doctors' requirement with its excellent discrimination and calibration.

[The relationship between preoperative renal failure and severe postoperative hypoxemia of patients received surgical procedures for Stanford A aortic dissection].

OBJECTIVE: To study the relationship between renal failure and severe postoperative hypoxemia of patients received surgical procedure for Stanford A aortic dissection. METHODS: Clinical data of 411 consecutive patients from January 2014 to April 2015, who received surgical procedure for Stanford A aortic dissection in Department of Cardiovascular Surgery of Beijing Anzhen Hospital, were collected retrospectively. The appearance of severe postoperative hypoxemia was recorded in all the cases. All the data about potential prognostic factors was put into the database and analyzed by univariate and multivariate Logistic regression respectively. RESULTS: Severe postoperative hypoxemia (PO2/FiO2<100 mmHg, 1 mmHg=0.133 kPa) happened on 69 cases within 48 hours after procedures, with the incidence rate of 17.1%. Both univariate and multivariate Logistic regression indicated the influence that preoperative creatinine clearance rate had on severe postoperative hypoxemia showed no statistical significance. However, the influence of preoperative serum creatinine showed statistical significance (OR=1.009, 95%CI: 1.000 to 1.018, P=0.048). CONCLUSIONS: The preoperative creatinine clearance rate of patients has no direct relationship with severe postoperative hypoxemia. But the preoperative serum creatinine could be regarded as an independent predictor of severe postoperative hypoxemia.

[Efficacy of endovascular repair in patients with abdominal aortic aneurysm complicating acute aortic syndrome].

OBJECTIVE: To evaluate the efficacy of simultaneous thoracic endovascular aortic repair (TEVAR) and endovascular aneurysm repair (EVAR) on abdominal aortic aneurysm (AAA) patients complicating acute aortic syndrome (AAS). METHODS: Data of 17 patients (16 men, mean age (65.2±6.9) years old) , who underwent simultaneous TEVAR and EVAR between September 2010 and June 2015 in Beijing Anzhen Hospital, were retrospectively reviewed.All patients were diagnosed with concomitant AAA and AAS by preoperative CTA.All abdominal aortic lesions were AAA and all thoracic aortic lesions were AAS.Under local anesthesia, simultaneous TEVAR and EVAR were performed and emergent simultaneous endovascular repair was performed in 2 patients.Follow up was made at 1 month, 3 months, 6 months, and yearly after the procedure.Procedure success rate, procedure related complications were evaluated. RESULTS: Procedure was successful in all patients.The length of thoracic coverage was (21.0±4.6) cm.The operation time was 150(120, 170) min, and the hospitalization time was 7 (6, 12) d. After a mean of 27.0(5.5, 44.5) months follow up, there were no acute cardiopulmonary complications and contrast induced nephropathy.One patient developed spinal cord ischemia and resolved after treatment.One patient was died for aneurysm rupture at 6 months post operation.One patient developed type Ⅰb endoleak for expansion of right iliac artery at 9 months post operation and was successfully sealed by iliac stent-graft extension. CONCLUSIONS: Combined TEVAR and EVAR can be performed successfully in patients with AAA complicating AAS.When anatomically feasible, simultaneous TEVAR and EVAR can be considered as a effective and safe therapy alternative to patients with multilevel aortic diseases.

Stability of two-dimensional PN monolayer sheets and their electronic properties.

Three two-dimensional phosphorus nitride (PN) monolayer sheets (named as α-, ß-, and γ-PN, respectively) with fantastic structures and properties are predicted based on first-principles calculations. The α-PN and γ-PN have a buckled structure, whereas ß-PN shows puckered characteristics. Their unique structures endow these atomic PN sheets with high dynamic stabilities and anisotropic mechanical properties. They are all indirect semiconductors and their band gap sensitively depends on the in-plane strain. Moreover, the nanoribbons patterned from these three PN monolayers demonstrate a remarkable quantum size effect. In particular, the zigzag α-PN nanoribbon shows size-dependent ferromagnetism. Their significant properties show potential in nano-electronics. The synthesis of the three phases of the PN monolayer sheet is proposed theoretically, which is deserving of further study in experiments.

Estradiol 1 mg and drospirenone 2 mg as hormone replacement therapy in postmenopausal Chinese women.

OBJECTIVES: Drospirenone is a novel progestogen that, combined with 17ß-estradiol, reduces the frequency and severity of menopausal vasomotor symptoms (VMS) in different populations. This double-blind, multicenter study compared the efficacy, safety and tolerability of 2 mg drospirenone/1 mg estradiol (DRSP/E2) vs. placebo in Chinese postmenopausal women with moderate to severe VMS. METHODS: Women, aged 45-65 years, were randomized to DRSP/E2 (n=183) or placebo (n=61) once daily for four 28-day cycles. Changes in the frequency and severity of hot flushes were analyzed as primary variables, together with other climacteric and urogenital symptoms, clinical global improvement, adverse events and physical/gynecological parameters. RESULTS: Relative changes in numbers of hot flushes/week were -80.4% for DRSP/E2 vs. -51.9% for placebo (treatment difference -28.5%, p<0.0001). There were trends toward a greater reduction in severity of hot flushes with DRSP/E2 treatment. Patients treated with DRSP/E2 were more often free from sweating episodes (p<0.0001) and vaginal dryness (p=0.0008). Other climacteric symptoms, including nervousness and pollakisuria, followed a trend of greater response with DRSP/E2. Similar to other combination HRT regimens, DRSP/E2 increased occurrences of bleeding, but these decreased over time. Adverse events in patients treated with DRSP/E2 were mostly mild to moderate and withdrawal rates were low. CONCLUSIONS: Daily treatment of postmenopausal Chinese women with DRSP/E2 for 16 weeks significantly reduced the incidence of hot flushes and demonstrated advantages vs. placebo for other climacteric symptoms. These results indicate that DRSP/E2 is effective, safe and well tolerated in postmenopausal Chinese women.