Electronic structures and quantum capacitance of twisted bilayer graphene with defects based on three-band tight-binding model.

Twisted bilayer graphene (tBLG) with C vacancies would greatly improve the density of states (DOS) around the Fermi level (EF) and quantum capacitance; however, the single-band tight-binding model only considering pz orbitals cannot accurately capture the low-energy physics of tBLG with C vacancies. In this work, a three-band tight-binding model containing three p orbitals of C atoms is proposed to explore the modulation mechanism of C vacancies on the DOS and quantum capacitance of tBLG. We first obtain the hopping integral parameters of the three-band tight-binding model, and then explore the electronic structures and the quantum capacitance of tBLG at a twisting angle of θ = 1.47° under different C vacancy concentrations. The impurity states contributed by C atoms with dangling bonds located around the EF and the interlayer hopping interaction could induce band splitting of the impurity states. Therefore, compared with the quantum capacitance of pristine tBLG (∼18.82 µF cm-2) at zero bias, the quantum capacitance is improved to ∼172.76 µF cm-2 at zero bias, and the working window with relatively large quantum capacitance in the low-voltage range is broadened in tBLG with C vacancies due to the enhanced DOS around the EF. Moreover, the quantum capacitance of tBLG is further increased at zero bias with an increase of the C vacancy concentration induced by more impurity states. These findings not only provide a suitable multi-band tight-binding model to describe tBLG with C vacancies but also offer theoretical insight for designing electrode candidates for low-power consumption devices with improved quantum capacitance.

The use of intra-aortic balloon pump in patients undergoing heart valve replacement: outcome and risk analysis.

BACKGROUND AND AIM OF THE STUDY: Intra-aortic balloon pump (IABP) in heart valve surgical patients is associated with a higher mortality than coronary artery bypass grafting (CABG). The study aim was to analyze the early outcome of heart valve surgical patients requiring IABP support, and to assess the risk factors for early mortality. METHODS: Among a cohort of 5,786 patients undergoing heart valve replacement without CABG, 81 (1.4%) required IABP support. Data from these latter patients were collected and analyzed retrospectively, and univariate and multivariate logistic regression were applied to identify risk factors for early mortality in patients requiring IABP support. RESULTS: IABP was inserted in 30 patients intraoperatively, and in 51 patients postoperatively. The overall mortality was 50.6%. Mortality in the intraoperative IABP subgroup was significantly lower than in the postoperative IABP subgroup (26.7% versus 64.7%, p = 0.001). The independent risk factors for early mortality were: age increasing by 10 years (OR 1.906, 95% CI: 1.165-3.116, p = 0.010) and pulmonary hypertension (OR 4.153, 95% CI: 1.380-12.499, p = 0.011). Intraoperative IABP insertion (OR 0.297, 95% CI: 0.100-0.876, p = 0.028) was identified as a protective factor compared to postoperative insertion. CONCLUSION: The mortality of patients requiring IABP support after heart valve replacement was high. The efficacy of intraoperative IABP insertion was better than a postoperative mandatory use. Clearly, more attention should be paid to older patients or those with pulmonary hypertension, who may benefit less from IABP.

Electronic instability in pressured black phosphorus under strong magnetic field.

In this paper, we have systematically studied the electronic instability of pressured black phosphorous (BP) under strong magnetic field. We first present an effective model Hamiltonian for pressured BP near theLifshitzpoint. Then we show that when the magnetic field exceeds a critical value, the nodal-line semimetal (NLSM) state of BP with a small band overlap re-enters the semiconductive phase by re-opening a small gap. This results in a narrow-bandgap semiconductor with a partially flat valence band edge. Moreover, we demonstrate that above this critical magnetic field, two possible instabilities, i.e. charge density wave phase and excitonic insulator (EI) phase, are predicted as the ground state for high and low doping concentrations, respectively. By comparing our results with the experiment (Sunet al2018Sci. Bull.631539), we suggest that the field-induced instability observed experimentally corresponds to an EI. Furthermore, we propose that the semimetallic BP under pressure with small band overlaps may provide a good platform to study the magneto-exciton insulators. Our findings bring the first insight into the electronic instability of topological NLSM in the quantum limit.

Chirality-selective topological magnon phase transition induced by interplay of anisotropic exchange interactions in honeycomb ferromagnet.

A variety of distinct anisotropic exchange interactions commonly exist in one magnetic material due to complex crystal, magnetic and orbital symmetries. Here we investigate the effects of multiple anisotropic exchange interactions on topological magnon in a honeycomb ferromagnet, and find a chirality-selective topological magnon phase transition induced by a complicated interplay of Dzyaloshinsky-Moriya interaction and pseudo-dipolar interaction, accompanied by the bulk gap close and reopen with chiral inversion. Moreover, this novel topological phase transition involves band inversion at high symmetry pointsKandK', which can be regarded as a pseudo-orbital reversal, i.e. magnon valley degree of freedom, implying a new manipulation corresponding to a sign change of the magnon thermal Hall conductivity. Indeed, it can be realized in 4dor 5dcorrelated materials with both spin-orbit coupling and orbital localized states, such as iridates and ruthenates,etc.This novel regulation may have potential applications on magnon devices and topological magnonics.

Chiral charge density wave induced by mirror symmetry breaking in kagome metal.

Kagome lattice provides a distinctive platform to investigate various correlated electron orders. Recently, an unconventional charge density wave (CDW) with novel chirality is observed in the kagome metalAV3Sb5(A= K, Rb, Cs), and the origin of which is still unclear. Here, using a tight-binding model and the mean-field method, we calculate the electron order in the quasi-two-dimensional kagome lattice with 1/3 electron filling, and show that the chiral CDW emerges under a set of parameters withC6rotational symmetry but without mirror symmetry. Physically, the reason why we choose this set of parameters is based on the possible tangential distortion of the kagome lattice. Our results provide a fresh insight to understand the microscopic origin of the unconventional CDW inAV3Sb5.

High-temperature magnetically topological candidate material Mn3Bi2Te6.

The Mn-Bi-Te family displaying magnetism and non-trivial topological properties has received extensive attention. Here, we predict that the antiferromagnetic structure of Mn3Bi2Te6with three MnTe layers is energetically stable and the magnetic energy difference of Mn-Mn is enhanced four times compared with that in the single MnTe layer of MnBi2Te4. The predicted Néel transition point is raised to 102.5 K, surpassing the temperature of liquid nitrogen. The topological properties show that with the variation of the MnTe layer from a single layer to three layers, the system transforms from a non-trivial topological phase to a trivial topological phase. Interestingly, the ferromagnetic state of Mn3Bi2Te6is a topological semimetal and it exhibits a topological transition from trivial to non-trivial induced by the magnetic transition. Our results enrich the Mn-Bi-Te family system, offer a new platform for studying topological phase transitions, and pave a new way to improve the working temperature of magnetically topological devices.

[Methods and results of surgical treatment for aortic root pathology due to Stanford A aortic dissection].

OBJECTIVE: To investigate the effectiveness of surgical approaches, outcomes and prognosis of aortic root pathology due to Stanford A aortic dissection. METHODS: Retrospective analysis the clinical data of 161 patients (122 male and 39 female, mean age of (44 ± 21) years) underwent surgical treatment for Stanford A aortic dissection between January 2001 and June 2011. There were 146 patients of acute aortic dissection and 15 patients of chronic aortic dissection. All the patients had aortic root pathologies that included commissural prolapsed in 140 cases, more than moderate aortic insufficiency in 75 cases, aortic sinus intima rupture in 15 cases, right and/or left coronary artery tearing in 8 cases, right and/or left coronary artery dissection in 16 cases, aortic root aneurysm in 31 cases. RESULTS: Aortic root replacement (Bentall procedures) were used in 72 cases, aortic root remodeling (including aortic valve replacement) in 80 cases, aortic root reimplantation (David procedure) in 9 cases. The cardiopulmonary bypass time was shorter in aortic root remodeling group ((193 ± 42) minutes) than the other two groups ((210 ± 61) minutes, (197 ± 34) minutes, F = 3.22, P = 0.04). The in-hospital mortality was 8.1% (13 cases), 5 cases (6.9%) in aortic root replacement group, 7 cases (8.8%) in aortic root remodeling group, 1 case in aortic root reimplantation. The cause of death included respiratory failure (4 cases), permanent neurological deficits (3 cases), multiple organ failure (4 cases), acute renal failure (2 cases). The survivors were followed up for 6 months to 6 years. There was no patient required reoperation for aortic root pathologies. There was no statistically significant difference between aortic root remodeling group and reimplantation group (P > 0.05). CONCLUSIONS: The surgical treatment for aortic root pathology due to Stanford A aortic dissection is challenging. Appropriate procedures according to the specialty of aortic root pathology can be performed with favorable functional results.

Topological magnons in one-dimensional ferromagnetic Su-Schrieffer-Heeger model with anisotropic interaction.

Topological magnons in a one-dimensional (1D) ferromagnetic Su-Schrieffer-Heeger (SSH) model with anisotropic exchange interactions are investigated. Apart from the intercellular isotropic Heisenberg interaction, the intercellular anisotropic exchange interactions, i.e. Dzyaloshinskii-Moriya interaction and pseudo-dipolar interaction, also can induce the emergence of the non-trivial phase with two degenerate in-gap edge states separately localized at the two ends of the 1D chain, while the intracellular interactions instead unfavors the topological phase. The interplay among them has synergistic effects on the topological phase transition, very different from that in the two-dimensional (2D) ferromagnet. These results demonstrate that the 1D magnons possess rich topological phase diagrams distinctly different from the electronic version of the SSH model and even the 2D magnons. Due to the low dimensional structural characteristics of this 1D topological magnonic system, the magnonic crystals can be constructed from bottom to top, which has important potential applications in the design of novel magnonic devices.

[Perioperative monitoring and control of hyperglycemia during deep hypothermic circulatory arrest].

OBJECTIVE: To observe the trend of change in perioperative blood glucose level in patients undergoing deep hypothermic circulatory arrest (DHCA), in order to evaluate the influencing factors of inciting hyperglycemia and the clinical effects of insulin control. METHODS: In the Department of Cardiothoracic Surgery of Changhai Hospital, 176 patients underwent aortic operation under DHCA from January 2000 to January 2010. Blood glucose, arterial blood gas and lactate levels were determined at four time points, including pre-cardiopulmonary bypass (CPB), pre-DHCA, post-DHCA, and at admission to intensive care unit (ICU). Hyperglycemia after surgery was controlled at the level of 6-8 mmol/L by intermittent subcutaneous injection or intravenous micropump injection of insulin. At the same time, the cumulative amount of insulin within 24 hours after surgery was recorded. RESULTS: The blood glucose (mmol/L) level at pre-DHCA time point was significantly higher than that of pre-CPB (9.62 ± 1.79 vs. 5.04 ± 1.401,P<0.05), and the blood glucose level was further elevated at the time point of post-DHCA (14.91 ± 2.36,P<0.01) and in-ICU (15.32 ± 2.47) compared with that of pre-CPB (P<0.01). The level of blood glucose elevation was positively correlated with blood lactate level. One hundred and thirty-four patients (76.1%) insulin was given with intravenous micropump due to poor effect of intermittent subcutaneous injection of insulin in controlling blood glucose. Among whom 30 patients (17.0%) developed the phenomenon of insulin resistance. Perioperative hyperglycemia during DHCA was associated with old age (≥ 50 years old), primary hypertension, serious aortic valve disease, diabetes or coronary heart disease, emergency operation, CPB time ≥ 3 hours and DHCA time ≥ 45 minutes. The cumulative amount of insulin within 24 hours after surgery was increased significantly. The results of blood glucose (mmol/L) in-ICU were as follows : age ≥ 50 years old or < 50 years old (18.66 ± 2.52 vs. 12.90 ± 2.27); hypertension with and without (18.98 ± 2.55 vs. 12.31 ± 2.34); serious aortic valve disease with and without (19.59 ± 2.95 vs. 12.13 ± 2.23); diabetes with and without (20.62 ± 1.76 vs. 11.75 ± 1.11); coronary heart disease with and without (19.77 ± 2.98 vs. 12.01 ± 2.02); emergency operation with and without (19.78 ± 1.97 vs. 12.23 ± 1.38); CPB time ≥ 3 hours or < 3 hours (19.86 ± 1.89 vs. 11.70 ± 1.15); DHCA time ≥ 45 minutes or < 45 minutes (19.92 ± 1.88 vs. 11.64 ± 1.12), and all of them should statistical difference (all P < 0.05). The cumulative amount of insulin (U) within 24 hours after surgery was as follows: age ≥ 50 years old or < 50 years old (169.5 ± 56.6 vs. 110.2 ± 38.5); hypertension with and without (171.6 ± 64.0 vs. 104.8 ± 34.3); aortic valve disease with and without (171.4 ± 36.8 vs. 109.4 ± 27.6); diabetes with and without (202.5 ± 46.7 vs. 100.4 ± 31.5); coronary heart disease with and without (178.5 ± 38.6 vs. 104.6 ± 26.4 ); emergency operation with and without (178.3 ± 35.7 vs. 102.7 ± 26.8); CPB time ≥ 3 hours or < 3 hours (168.6 ± 37.2 vs. 107.3 ± 27.5); DHCA time ≥ 45 minutes or < 45 minutes (172.5 ± 36.1 vs. 105.4 ± 28.7), and all of them showed significant statistical difference (all P < 0.05). and all of them showed significant statistical difference (all P < 0.05). CONCLUSION: DHCA may cause significant increase in perioperative blood glucose and lactate, and even may lead to insulin resistance. Patients often require continuous intravenous administration of large doses of insulin. Perioperative hyperglycemia during DHCA is related to many factors, which should be considered in control of blood glucose.

Investigation on the interlayer coupling and bonding in layered nitride-halides ThNF and ThNCl.

Motivated by recent experimental observation [N. Z. Wang, et al., Inorg. Chem., 2019, 58, 9897], we investigated the electronic properties and chemical bonding in layered nitride-halide compounds ThNF and ThNCl using first-principles calculations to illustrate the interlayer interaction. The energy gaps and chemical valences of both compounds are in agreement with experimental data. The crystal orbital Hamiltonian population (COHP) and charge density differential analysis show that interlayer chemical bonding plays a more important role than that van der Waals interactions in ThNF and ThNCl, in contrast to isostructural ZrNCl and HfNCl. These results explain why it is difficult to intercalate ThNF and ThNCl with charged particles, as observed in experiments.

[Surgical treatment of congenital quadricuspid aortic valve].

OBJECTIVE: To improve the understanding of congenital quadricuspid aortic valve (QAV), explore its echocardiographic diagnostic value and summarize the methods and outcomes of surgical treatments. METHODS: The clinical data of 11 QAV patients from January 2000 to December 2008 were retrospectively analyzed. There were 9 males and 2 females with a mean operative age of (32±16) years (range: 4-55). RESULTS: In 766 patients undergoing aortic valve surgery, 11 were of congenital quadricuspid aortic valve (1.4%); cardiac pathology: infective endocarditis (n=1), left superior vena cava (n=1), aortic aneurysm (n=1), mitral prolapse (n=1) and tricuspid insufficiency (n=1). The patients of congenital QAV deformity was diagnosed by echocardiography (n=7), misdiagnosed as single valve (n=1), misdiagnosed as bicuspid valve (n=1) and misdiagnosed as rheumatic heart disease (n=2). Type B (n=7), Type A (n=2), Type F (n=1) and Type G (n=1). Eleven patients underwent the procedure of aortic valve replacement. And the concomitant procedures were aortic root broadening (n=1), ascending aortoplasty (n=1), mitral valvuloplasty (n=1) and tricuspid valvuloplasty (n=1). CONCLUSION: Quadricuspid aortic valve is rare in clinical practice. And echocardiography plays an important diagnostic role. Surgical replacement of aortic valve is the first-line therapy for these patients.

[Reoperative valve replacement in patients undergoing cardiac reoperation: a report of 104 cases].

OBJECTIVE: To review the experience of reoperative valve replacement for 104 patients. METHODS: From January 2002 to December 2009, 104 patients underwent heart valve replacement in reoperations, accounting for 2.92% of the total patient population (3557 cases) who had valve replacement during this period. In this group, 53 male and 51 female patients were included with a median age of 46 years (ranged from 13 to 72 years). The reasons of reoperation included 28 cases suffered from another valve lesion after valve replacement, 10 cases suffered from valve lesion after mitral valvuloplasty, 19 cases suffered from perivalvular leakage after valve replacement, 18 cases suffered from valve lesion after previous correction of congenital heart defect, 7 cases suffered from bioprosthetic valve decline, 10 cases suffered from prosthetic valve endocarditis, 9 cases suffered from dysfunction of machine valve, and 3 cases suffered from other causes. The re-operations were mitral and aortic valve replacement in 2 cases, mitral valve replacement in 59 cases, aortic valve replacement in 24 cases, tricuspid valve replacement in 16 cases, and Bentall's operation in 3 cases. The interval from first operation to next operation was 1 month-19 years. RESULTS: There were 8 early deaths from heart failure, renal failure and multiple organ failure (early mortality 7.69%). Major complications were intraoperative hemorrhage in 2 cases, re-exploration for mediastinal bleeding in 2 cases and sternotomy surgical site infection in 1 case. Complete follow-up (3 months-7 years and 2 months) was available for all patients. Two patients died, one patient died of intracranial hemorrhage, and another cause was unknown. CONCLUSION: Satisfactory short-term and long-term results can be obtained in reoperative valve replacement with appropriate timing of operation control, satisfactory myocardial protection, accurate surgical procedure and suitable perioperative treatment.

Superconducting pairing symmetry and energy gaps of the two-orbital t-t'-J-J' model: comparisons with the ARPES experiments in iron pnictides.

Motivated by the discovery of the iron-based superconductors, we present the theoretical results on the superconducting phase diagram, the temperature-dependent Fermi surface structures in normal state and the angle-resolved photoemission spectroscopy (ARPES) character of quasiparticles of the two-orbital t-t'-J-J' model. In the reasonable physical parameter region of LaFeAsO(1-x)F(x), we find the superconducting phase is stable, and the pairing symmetry is weakly anisotropic and nodeless d(x(2)-ηy(2))+S(x(2)y(2))-wave, qualitatively in agreement with the ARPES experiments in iron pnictide superconductors. Nevertheless, the two ratios of the energy gaps to T(c) deviate from the ARPES data, suggesting that a more elaborate theoretical model is needed.

Anharmonic effect on lattice distortion, orbital ordering and magnetic properties in Cs(2)AgF(4).

We develop the cluster self-consistent field method incorporating both electronic and lattice degrees of freedom to study the origin of ferromagnetism in Cs(2)AgF(4). After self-consistently determining the harmonic and anharmonic Jahn-Teller distortions, we show that the anharmonic distortion stabilizes the staggered x(2)-z(2)/y(2)-z(2) orbital and ferromagnetic ground state, rather than the antiferromagnetic one. The amplitudes of lattice distortions, Q(2) and Q(3), the magnetic coupling strengths, J(x,y), and the magnetic moment are in good agreement with the experimental observations.

Charge and spin orderings in triangular t-J-V model with quarter filling: application to Na(0.5)CoO(2).

We investigated the ground state (GS) properties of the single-orbital t-J-V model in a quarter-filling two-dimensional triangular lattice with the slave-boson mean-field approach. We found that the charge ordering (CO) and spin ordering arising from the spin exchange interaction J competes with that from the inter-site Coulomb interaction V. For comparatively large J, the stable GS is insulating with striped CO and antiferromagnetic ordering, avoiding the homogeneous frustrated phase. Accompanying the insulating CO phase, a small insulating gap is opened. Within a reasonable J and V parameter region, our results are consistent with the recent neutron scattering experiments in Na(0.5)CoO(2), which possibly elucidate its CO, magnetic and other GS properties.

[Experiences on surgical treatment of severe aortic valve stenosis: a report of 171 cases].

OBJECTIVE: To analyze the experiences on surgical treatment of severe aortic valve stenosis. METHODS: From December 1990 to December 2006, 171 patients with severe aortic valve stenosis underwent aortic valve replacement (AVR). There were 135 males and 36 females aged from 10 to 75 years old, with a mean of (45.8 +/- 15.6) years old. The intervals between the first episode of exertion dyspnea and administration to operation were 2 months to 52 years. The pathological lesions of the group were rheumatic aortic valve stenosis in 75 cases, calcified aortic stenosis in 66 cases, bicuspid aortic valve in 26 cases and other congenital aortic valve stenosis in 4 cases. One hundred and twenty-four patients underwent AVR, 7 AVR combined with replacement of the ascending aorta, 5 AVR with coronary artery bypass grafting, 19 AVR with mitral valve plasty (MVP), 8 AVR with plasty of the ascending aorta and 8 AVR with enlargement of the aortic root. RESULTS: The averaged operation time was (4.4 +/- 0.6) h. Cardiopulmonary bypass (CPB) time was (124.7 +/- 38.5) min and the aorta clamp time was (78.3 +/- 21.7) min. The averaged blood loss during operation was (754.5 +/- 518.4) ml. All the procedures were successfully performed and all patients were weaned off CPB uneventfully. The indication of early complications was 12.3% (21/171), including low cardiac output syndrome in 7 cases, multi-organ failure in 3 cases, endocarditis in 1 case, renal dysfunction in 4 cases, ventricular fibrillation in 1 case, excessive bleeding in 2 cases, III atrial-ventricular block in 2 cases, and mediastinal infection in 1 case. The total mortality was 5.8% (10/171) with the main causes as cardiac failure for 4 cases, arrhythmia for 1 case, multi-organ failure for 4 cases, and infectious endocarditis for 1 case. CONCLUSIONS: Successful management of severe aortic valve stenosis requires sophisticated surgical techniques and experienced peri-operative care. Satisfactory results can be achieved if valve replace surgery is performed adequately.

[Aortic valve replacement: the experiences of 1026 cases].

OBJECTIVE: To study the changes in pathogenic causes and the prognosis of aortic valve replacement (AVR). METHODS: The clinical data of 1026 patients undergoing AVR from December 1980 to December 2006 were analyzed retrospectively. The mortality, morbidity, changes in pathogenic causes and risk factors were analyzed. RESULTS: The postoperative mortality and complication morbidity were 4.3% and 10.6% respectively within 30 days followed operation. Main causes of operative death were heart failure, multi organ failure and endocarditis. The major risk factors for operative death were left ventricle ejection fraction less than 0.4, endocarditis, valve regurgitation and emergency operation before AVR. Late mortality was 0.54% patient-year (3.4%), most of whom died of heart failure, endocarditis and arrhythmias. Patients underwent reoperation 0.22% patient-year (1.4%), with the causes of endocarditis and perivalvular fistula. CONCLUSIONS: Morbidity of rheumatic damage in aortic valve has decreased, while valve degeneration has increased gradually in the recent years. Avoiding prosthesis-patient mismatch, good postoperatively guide and prevention of endocarditis can improve the prognosis of AVR.

Does PGA external stenting reduce compliance mismatch in venous grafts?

BACKGROUND: Autogenous vein grafting is widely used in regular bypassing procedures. Due to its mismatch with the host artery in both mechanical property and geometry, the graft often over expands under high arterial blood pressure and forms a step-depth where eddy flow develops, thus causing restenosis, fibrous graft wall, etc. External stents, such as sheaths being used to cuff the graft, have been introduced to eliminate these mismatches and increase the patency. Although histological and immunochemical studies have shown some positive effects of the external stent, the mechanical mismatch under the protection of an external stent remains poorly analyzed. METHODS: In this study, the jugular veins taken from hypercholesterolemic rabbits were transplanted into the carotid arteries, and non-woven polyglycolic acid (PGA) fabric was used to fabricate the external stents to study the effect of the biodegradable external stent. Eight weeks after the operation, the grafts were harvested to perform mechanical tests and histological examinations. An arc tangent function was suggested to describe the relationship between pressure and cross-sectional area to analyse the compliance of the graft. RESULTS: The results from the mechanical tests indicated that grafts either with or without external stents displayed large compliance in the low-pressure range and were almost inextensible in the high-pressure range. This was very different from the behavior of the arteries or veins in vivo. The data from histological tests showed that, with external stents, collagen fibers were more compact, whilst those in the graft without protection were looser and thicker. No elastic fiber was found in either kind of grafts. Furthermore, grafts without protection were over-expanded which resulted in much bigger cross-sectional areas. CONCLUSION: The PGA external extent contributes little to the reduction of the mechanical mismatch between the graft and its host artery while remodeling develops. For the geometric mismatch, it reduces the cross-section area, therefore matching with the host artery much better. Although there are some positive effects, conclusively the PGA is not an ideal material for external stent.

Primary triple valve surgery for advanced rheumatic heart disease in Mainland China: a single-center experience with 871 clinical cases.

BACKGROUND: Triple valve surgery (TVS) is still of choice for advanced rheumatic heart disease (RHD), which has been associated with reported poor early and late outcomes. We describe the short- and long-term results after TVS in last two decades in Mainland China. METHODS: From January 1985 to January 2005, a total of 871 patients (217 men, 654 women), with mean age of 42+/-11 years, underwent primary TVS for isolated advanced RHD. All patients received replacement procedures in mitral and aortic position (845 mechanical, 26 bioprosthetic), and 840 patients received repair procedures and the other 31 received replacement procedures in tricuspid position (9 mechanical, 22 bioprosthetic). Preoperative, perioperative, and postoperative data were retrospectively analyzed and risk factors affecting early and late survival were evaluated. RESULTS: The 30-day hospital mortality was 8% (n=71). Presence of ascites, New York Heart Association (NYHA) class IV and lower left ventricular ejection fraction (LVEF) were identified as independent risk factors for hospital mortality. Overall long-term survival rate was 71%+/-3% at 5 years, and 59%+/-5% at 10 years. The cardiac survival rate was 75%+/-3% at 5 years and 63%+/-4% at 10 years. The event-free survival rate at 5 years and 10 years was 61%+/-6% and 41%+/-13%, respectively. Multivariate analysis revealed advanced age, NYHA class IV and lower LVEF were associated with increased late mortality. The freedom from thromboembolism and anticoagulation-related hemorrhage at 10 years was 90%+/-4% and 81%+/-5%, respectively. Of the 508 patients still alive, 376 (74%) were in NYHA class I and II. CONCLUSIONS: Primary TVS for advanced RHD appears to offer satisfactory short- and long-term results with excellent symptomatic improvement. Cardiac-related late mortality following TVS may be improved by early surgical treatment before NYHA class IV or deterioration of LVEF occurs.