Systematic review and meta-analysis of current evidence in endograft therapy for spontaneous isolated superior mesenteric artery dissection.

The role of endovascular stent therapy (EST) in the treatment of spontaneous isolated superior mesenteric artery dissection (SISMAD) has gained momentum in recent years but remains controversial. We gathered research examining the advantages and disadvantages of EST for SISMAD patients. Primary outcomes involved both immediate and long-term results. Random or fixed effect models were used for effect size (ES) calculation with 95% confidence interval (CI) based on 50% heterogeneity threshold. Our analysis incorporated data from 21 studies including 611 SISMAD cases treated by EST. Our findings show a complication rate of approximately 1% following EST (95%CI 0.01-0.02, I2 = 0%, P = 0.97), with a bare minimum mortality rate of < 1% (95%CI 0.00-0.01, I2 = 0%, P > 0.05) and a reintervention rate of < 1% (95%CI 0.00-0.01, I2 = 0%, P = 0.89). We also found technique success and symptom resolution approaching 94% and 99%, respectively, in the immediate postoperative phase. In the long run, we observed a recurrence of symptoms at 3% (95%CI 0.00-0.06, I2 = 58.6%, P < 0.01), creation of new dissections at 1% (95%CI 0.00-0.02, I2 = 0%, P = 0.73), aneurysm progression at 2% (95%CI 0.00-0.03, I2 = 42.7%, P = 0.12), reintervention due to complications at 3% (95%CI 0.00-0.05, I2 = 0%, P = 0.43) and stenotic stents at 12% (95%CI 0.04-0.23, I2 = 77.5%, P < 0.01). Nevertheless, high levels of stent patency 98% (95% CI 0.97-1.00, I2 = 0%, P = 0.51) and complete remodeling 88% (95% CI 0.82-0.94, I2 = 65.5%, P < 0.05) were observed postoperatively. Overall, EST presents minimal complications and promising long-term outcomes for SISMAD, although the prevalence of stent stenosis requires further attention.

Robustness of the synergistic partial-denitrification, anammox, and fermentation process for treating domestic and nitrate wastewaters under fluctuating C/N ratios.

The synergistic partial-denitrification, anammox, and fermentation (SPDAF) process presents a promising solution to treat domestic and nitrate wastewaters. However, its capability to handle fluctuating C/N ratios (the ratios of COD to total inorganic nitrogen) in practical applications remains uncertain. In this study, the SPDAF process was operated for 236 days with C/N ratios of 0.7-3.5, and a high and stable efficiency of nitrogen removal (84.9 ± 7.8%) was achieved. The denitrification and anammox contributions were 6.1 ± 7.1% and 93.9 ± 7.1%, respectively. Batch tests highlighted the pivotal role of in situ fermentation at low biodegradable chemical oxygen demand (BCOD)/NO3- ratios. As the BCOD/NO3- ratios increased from 0 to 6, the NH4+ and NO3- removal rates increased, while the anammox contribution decreased from 100% to 80.1% but remained the primary pathway of nitrogen removal. The cooperation and balanced growth of denitrifying bacteria, anammox bacteria, and fermentation bacteria contributed to the system's robustness under fluctuating C/N ratios.

The urgent need to control volatile organic compound pollution over the Qinghai-Tibet Plateau.

Owing to the impact of the western development of China, there have been signs of air pollution over the Qinghai-Tibet Plateau in recent years. However, monitoring data on atmospheric volatile organic compounds (VOCs) are lacking in plateau areas. Here, VOCs concentrations in urban and background areas in North China and the Qinghai-Tibet Plateau were observed from 2012 to 2014 and 2020 to 2022, respectively. Compared to 2012-2014, the concentration of VOCs increased to 2.5 times in urban areas on the Qinghai-Tibet Plateau, which was equivalent to that in North China. Oil, gas, and solvent evaporation caused by a low atmospheric pressure is the primary factor for the increase in VOCs in plateau areas, and weak VOCs degradation is the secondary factor. Hence, we put forward the VOCs control strategies in plateau areas and point out the defects in the current research.

Significant contribution of lightning NOx to summertime surface O3 on the Tibetan Plateau.

Lightning generates nitrogen oxides (NOx) in the troposphere, an important precursor of tropospheric ozone (O3). The Tibetan Plateau (TP) is considered to be a global atmospheric background location with limited anthropogenic influences. However, the observed summertime surface O3 concentration on the TP is 25% higher than that in highly polluted regions (e.g., southern China). Previous studies have suggested that lightning-produced NOx (LNOx) can affect the concentration of surface O3. We used the Weather Research and Forecasting coupled with chemistry (WRF-Chem) model combined with satellite, ground-based, and airborne observations to evaluate the contribution of LNOx to the surface O3 budget on the TP. Our results showed that LNOx contributed approximately 15% of the surface NOx emission on the TP in summer. Accordingly, the contribution of LNOx to the summertime surface daily maximum 8-h average (MDA8) O3 on the TP was 9.3 ± 7.1 ppb, which was 17.5% ± 14.5% of the total concentration of the surface MDA8 O3. In addition, our study found that the number of moles of NO produced per lightning flash (LNOx production efficiency) significantly affected the surface concentration of NOx, OH, and MDA8 O3. Increasing the LNOx production efficiency (PE) from 0 to 330 mol NO flash-1 increased the concentration of MDA8 O3 by up to 20% on the TP. Our study revealed that lightning significantly affects the atmospheric chemical processes involving O3 on the TP.

New insights into denitrification and phosphorus removal with degradation of polycyclic aromatic hydrocarbons in two-sludge system.

Polycyclic aromatic hydrocarbons (PAHs) have led to failure of waste water treatment plant operations. In this study, a two-sludge system was used to solve this problem of simultaneously removing phosphorus, nitrogen, and PAHs. The results showed that increasing the maximum PAHs concentration to 15 mg/L did not have any negative effect on the removal rates of total nitrogen (79.68%) and chemical oxygen demand (75.94%); however, the phosphorus removal efficiency decreased to 61.16%. The system exhibited a stronger degradation ability for phenanthrene. Thauera, Hydrogenophaga, and Hyphomicrobium were enriched, which resulted in good denitrification, and contributed to PAHs removal. PAHs mixture promoted PAHs functional genes but restrained denitrification functional genes. However, single naphthalene enhanced denitrification functional genes, which confirmed the feasibility of denitrification coupled with PAHs degradation. In conclusion, for the removal of pollutants from sewage treatment, nitrogen and phosphorus removal coupled with PAHs could be maintained by selecting a two-sludge system.

Transport of Asian surface pollutants to the global stratosphere from the Tibetan Plateau region during the Asian summer monsoon.

Due to its surrounding strong and deep Asian summer monsoon (ASM) circulation and active surface pollutant emissions, surface pollutants are transported to the stratosphere from the Tibetan Plateau region, which may have critical impacts on global climate through chemical, microphysical and radiative processes. This article reviews major recent advances in research regarding troposphere-stratosphere transport from the region of the Tibetan Plateau. Since the discovery of the total ozone valley over the Tibetan Plateau in summer from satellite observations in the early 1990s, new satellite-borne instruments have become operational and have provided significant new information on atmospheric composition. In addition, in situ measurements and model simulations are used to investigate deep convection and the ASM anticyclone, surface sources and pathways, atmospheric chemical transformations and the impact on global climate. Also challenges are discussed for further understanding critical questions on microphysics and microchemistry in clouds during the pathway to the global stratosphere over the Tibetan Plateau.

Effect of inflammation on the biomechanical strength of involved aorta in type A aortic dissection and ascending thoracic aortic aneurysm: An initial research.

OBJECTIVE: Type A aortic dissection (AD) and ascending thoracic aortic aneurysm (AA) are thoracic vascular diseases with similar initial pathology but inequable clinical features and outcomes, where local and systemic inflammation play an important part. We aimed to observe and analyze the differences and correlation between inflammation and pathological changes in the aorta and biomechanical strength between AD and AA. METHODS: From August 2011 to February 2013, 20 patients with AD (AD group) and 13 patients with AA (AA group) who underwent aorta surgery were included. Serum concentrations of total cholesterol (TC), triglycerides (TG), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels were measured just before surgical anesthesia. The longitudinal vessel samples of the affected ascending aorta were harvested during surgery and prepared for subsequent pathological observation and uniaxial tension test to measure the longitudinal tensile strength (TS). Samples were also prepared for further measurement of tissue homogenized TNF-α and IL-6 concentrations. RESULTS: No significant difference was seen between the two groups with respect to baseline data, and the serum concentrations of TC and TG of both the groups were within the normal range (p>0.05). Blood and tissue homogenized levels of IL-6 and TNF-α were significantly higher in the AD group than in the AA group (p<0.001). Pathological observation of the aortic tissue showed more inflammatory cells infiltration and elastic fiber destruction in the AD group than in the AA group, indicating significant aortic medial degeneration. Uniaxial tensile tests showed that the longitudinal TS was significant lower in the AD group than in the AA group (p<0.001). The longitudinal TS showed negative correlations with serum and tissue homogenized concentrations of IL-6 and TNF-α in the AD group (p<0.05), whereas no such significant correlation was seen in the AA group. CONCLUSION: Patients with AD had acute systemic inflammation, along with acute inflammation and declined biomechanical strength of the affected aorta. The serum and tissue homogenized concentrations of IL-6 and TNF-α showed a significant correlation with the biomechanical strength of affected aorta in AD.

Rare association of two cardiovascular malformations successfully corrected in a single surgery: a case report.

BACKGROUND: Partial anomalous pulmonary venous connection (PAPVC) without an atrial septal defect (ASD) associated with coarctation of the aortic arch is a rare congenital cardiac anomaly. This rare combination is only described in a few studies; none report the correction of these two malformations in a single surgery. CASE PRESENTATION: A 5-year-old girl was admitted to our hospital because the echocardiography revealed coarctation of the aortic arch; this diagnosis was confirmed by computed tomography (CT), which also showed her left superior pulmonary vein draining into the vertical vein without ASD (Fig. 1). She exhibited no special clinical symptoms. Her upper-limb blood pressure was approximately 110/90 mmHg, whereas her lower-limb blood pressure was approximately 75/50 mmHg. CONCLUSIONS: We surgically repaired the case of PAPVC to the vertical vein with aortic coarctation, in which the two cardiovascular malformations were corrected in a single surgery without cardiopulmonary bypass.

Efficient transport of tropospheric aerosol into the stratosphere via the Asian summer monsoon anticyclone.

An enhanced aerosol layer near the tropopause over Asia during the June-September period of the Asian summer monsoon (ASM) was recently identified using satellite observations. Its sources and climate impact are presently not well-characterized. To improve understanding of this phenomenon, we made in situ aerosol measurements during summer 2015 from Kunming, China, then followed with a modeling study to assess the global significance. The in situ measurements revealed a robust enhancement in aerosol concentration that extended up to 2 km above the tropopause. A climate model simulation demonstrates that the abundant anthropogenic aerosol precursor emissions from Asia coupled with rapid vertical transport associated with monsoon convection leads to significant particle formation in the upper troposphere within the ASM anticyclone. These particles subsequently spread throughout the entire Northern Hemispheric (NH) lower stratosphere and contribute significantly (∼15%) to the NH stratospheric column aerosol surface area on an annual basis. This contribution is comparable to that from the sum of small volcanic eruptions in the period between 2000 and 2015. Although the ASM contribution is smaller than that from tropical upwelling (∼35%), we find that this region is about three times as efficient per unit area and time in populating the NH stratosphere with aerosol. With a substantial amount of organic and sulfur emissions in Asia, the ASM anticyclone serves as an efficient smokestack venting aerosols to the upper troposphere and lower stratosphere. As economic growth continues in Asia, the relative importance of Asian emissions to stratospheric aerosol is likely to increase.

A modified Cox maze IV procedure: a simpler technique for the surgical treatment of atrial fibrillation.

OBJECTIVES: To determine the effectiveness of a simplified surgical treatment method for atrial fibrillation (AF). METHODS: Between September 2012 and October 2013, 120 patients (mean age, 52.3 ± 8.8 years) underwent valve surgery and concomitant bipolar radiofrequency ablation for the treatment of AF. Patients were randomized to a Cox maze IV procedure (CMP-IV) group (n = 60) or a modified CMP-IV (MCMP-IV) group (n = 60). Freedom from AF was defined as freedom from any left atrial arrhythmia lasting <30 s and no requirement of antiarrhythmic drugs after 6 months. Data were recorded at postoperative follow-up examinations, which were scheduled at 1, 3, 6 and 12 months, and annually thereafter. RESULTS: No ablation-related complications occurred in either group. The mean ablation time was longer in the CMP-IV group than in the MCMP-IV group (18.5 ± 1.7 vs 16.6 ± 1.6 min, P < 0.001). The mean follow-up time was 32.4 ± 3.6 months (range, 26-39 months). Freedom from AF tended to be higher, but not significantly so, among the MCMP-IV group than among the CMP-IV group over the entire follow-up period. CONCLUSIONS: The MCMP-IV is an effective surgical procedure for the treatment of AF. In certain patients, such as those with anatomic variations of the pulmonary veins, the MCMP-IV is simpler than the CMP-IV. CLINICAL TRIALS REGISTRATION ID: ChiCTR-TRC-12002742.

Papillary fibroelastoma of the aortic valve in association with rheumatic heart disease: a case report.

BACKGROUND: Papillary fibroelastoma (PFE) is a rare primary cardiac neoplasm that is usually discovered incidentally at autopsy or during cardiac surgery. PFE combined with rheumatic heart disease (RHD) is extremely rare, and only a few cases have been reported. Additionally, the growth rate of the tumor is unknown. CASE PRESENTATION: Here, we present a very rare case of PFE of the aortic valve combined with RHD, which were identified in a female patient who survived for 5 years without surgical intervention, and who subsequently underwent successful surgical treatment. CONCLUSIONS: PFEs may be generally slow-growing tumors, however, the better treatment of choice may be surgery because it produces good curative effects with very low risk of complications, while preventing serious disease consequences.

Diagnosis and surgical treatment for isolated tricuspid Libman-Sacks endocarditis: a rare case report and literatures review.

Libman-Sacks endocarditis (LSE), characterized by verrucous vegetations formation, is a typical cardiac manifestation of autoimmune diseases such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). It primarily leads to lesions of cardiac valves and mostly involved valves are mitral and aortic, but isolated tricuspid valve involvement is exceptional. Here we reported a 20-years-old female with past SLE history suffered from acute right heart failure caused by multiple tricuspid vegetations and valve regurgitation. The patient recovered following tricuspid valve replacement with a bioprosthesis. Transesophageal echocardiography(TEE), especially real time 3-dimensional (RT3D) TEE provide a better imaging modality for assessing cardiac valvular involvement of LSE. For patients with active SLE/APS course, uncontrolled systemic inflammation may made it difficult for surgical exposure and suture. The durability of bioprosthesis for this patient and the prosthesis selection for tricuspid LSE both need further follow-up and more clinical investigation.

Rare early prosthesis obstruction after mitral valve replacement: a case report and literature review.

As a dreadful complication after the mechanical heart valve replacement, prosthetic valve obstruction caused by pannus formation occurs increasingly with time. The authors here present a case of 42-year-old woman who was urgently admitted to hospital with acute heart failure symptoms due to the mechanical mitral valve failure only 3 months after surgery. Transthoracic and transesophageal echocardiography demonstrated that the bileaflet of the mitral prosthesis were completely immobilized with only a small transvalvular jet remained. During the reoperation, the reason of the prosthetic valve obstruction was attributed to the noncircular pannus ingrowth extending from the atrioventricular side. For a better understanding of the prosthetic valve dysfunction caused by pannus formation, the authors then compile a literature review to briefly discuss the status quo of the clinical characteristics of this uncommon complication.

A canine model of multiple organ dysfunction following acute type-A aortic dissection.

PURPOSE: Despite recent advances in surgical techniques and perioperative management, the mortality rate in patients with type-A aortic dissection remains high. The establishment of an animal model that exhibits the clinical features of acute aortic dissection would facilitate investigations of the pathogenesis of aortic dissection and the development of appropriate treatments. METHODS: Twelve beagle dogs were divided into two groups: (1) an experimental group treated with the modified surgical procedure to generate an ascending aortic dissection (n = 6); and (2) a control group treated with a median sternotomy but without aortic dissection. All animals received continuous intravenous infusion of adrenaline to achieve controlled hypertension. The tearing length of the aortic intima, the pathological changes, the plasma levels of inflammatory mediators, and the organ functions were dynamically examined and compared. RESULTS: The modified surgical procedure plus controlled hypertension successfully established a novel canine model of acute type-A aortic dissection. In the experimental group, the tearing length of the aortic intima reached the abdominal aorta (average 17 cm), and a false lumen was formed in the aortic media. The lung and intestinal tract had obvious structural injuries. The plasma levels of all inflammatory mediators tested, including tumor necrosis factor-α, interleukin-6, interleukin-10, and endotoxin, were significantly higher in the experimental animals than in the control group. The functional examination of the liver and kidneys revealed substantial disturbances, as reflected by the elevated plasma levels of alanine aminotransferase, aspartate aminotransferase, creatinine, and blood urea nitrogen in the experimental group. CONCLUSIONS: A novel canine model of acute Stanford type-A aortic dissection has been developed, which showed multiple organ dysfunction that mimicked the clinically relevant features observed in man. This aortic dissection model is unique, and may further improve our understanding of the underlying pathogenesis of aortic dissections.