Biochar and nano biochar: Enhancing salt resilience in plants and soil while mitigating greenhouse gas emissions: A comprehensive review.

Salinity stress poses a significant challenge to agriculture, impacting soil health, plant growth and contributing to greenhouse gas (GHG) emissions. In response to these intertwined challenges, the use of biochar and its nanoscale counterpart, nano-biochar, has gained increasing attention. This comprehensive review explores the heterogeneous role of biochar and nano-biochar in enhancing salt resilience in plants and soil while concurrently mitigating GHG emissions. The review discusses the effects of these amendments on soil physicochemical properties, improved water and nutrient uptake, reduced oxidative damage, enhanced growth and the alternation of soil microbial communities, enhance soil fertility and resilience. Furthermore, it examines their impact on plant growth, ion homeostasis, osmotic adjustment and plant stress tolerance, promoting plant development under salinity stress conditions. Emphasis is placed on the potential of biochar and nano-biochar to influence soil microbial activities, leading to altered emissions of GHG emissions, particularly nitrous oxide(N2O) and methane(CH4), contributing to climate change mitigation. The comprehensive synthesis of current research findings in this review provides insights into the multifunctional applications of biochar and nano-biochar, highlighting their potential to address salinity stress in agriculture and their role in sustainable soil and environmental management. Moreover, it identifies areas for further investigation, aiming to enhance our understanding of the intricate interplay between biochar, nano-biochar, soil, plants, and greenhouse gas emissions.

Optimizing potassium and nitrogen fertilizer strategies to mitigate greenhouse gas emissions in global agroecosystems.

The efficient management of fertilizer application in agriculture is vital for both food security and mitigating greenhouse gas (GHG) emissions. However, as potassium fertilizer (KF) is an essential soil nutrient, its impact on soil GHG emissions has received little attention. To address this knowledge gap and identify key determinants of GHG emissions, we conducted a comprehensive meta-analysis of 205 independent experiments conducted worldwide. Our results revealed that, in comparison to sole nitrogen fertilizer (NF) application, the concurrent use of KF elevated nitrous oxide (N2O) and methane (CH4) emissions by 39.5 % and 21.1 %, respectively, while concurrently reducing carbon dioxide (CO2) emissions by 8.1 %. The ratio of nitrogen and potassium fertilizer input (NF/KF) is identified as the primary factor explaining the variation in N2O emissions, whereas the type of KF plays a crucial role in determining CH4 and CO2 emissions. We observed a significant negative correlation between the NF/KF ratio and response ratios of N2O and CH4 emissions and a positive correlation with CO2 emissions response ratios. Furthermore, our findings indicate that when the NF/KF ratio surpasses 1.97, 4.61, and 3.78, respectively, the impact of KF on reducing N2O, CH4, and CO2 emissions stabilizes. Overall, our results underscore that the global integration of KF into agricultural practices significantly influences N2O and CH4 emissions, while simultaneously reducing CO2 emissions at a large scale. These findings provide a foundational framework and practical guidance for optimizing fertilizer application in the development of GHG emission reduction models.

Molecular characterization of genes involved in tolerance of cadmium in Triticum aestivum (L.) under Cd stress.

The NRAMPs (natural resistance-associated macrophage proteins) are major transporters for the absorption and transport of metals like Pb, Zn, Mn, Fe, and Cd in plants. While NRAMP gene family members have been extensively studied as metal transporters in model and other plants, little information has been reported on their role in Triticum aestivum, particularly in response to Cd stress. Current study reported 13 NRAMP candidates in the genome of T. aestivum. Phylogenetic analysis divided these into three clades. Motif and gene structure study showed that members in the same clades shared the same location and pattern, which further supported the phylogenetic analysis. The analysis of cis-acting elements in promoter sequences of NRAMP genes in wheat identified stress-responsive transcription factor binding sites. Multiple sequence alignment identified the conservation of important residues. Based on RNA-seq and qRT-PCR analysis, Cd stress-responsive variations of TaNRAMP gene expression were reported. This study provides comprehensive data to understand the TaNRAMP gene family, its features, and its expression, which will be a helpful framework for functional research.

A signature of pre-operative biomarkers of cellular senescence to predict risk of cardiac and kidney adverse events after cardiac surgery.

Objective: Understand the potential for pre-operative biomarkers of cellular senescence, a primary aging mechanism, to predict risk of cardiac surgery-associated adverse events. Methods: Biomarkers of senescence were assessed in blood samples collected prior to surgery in 331 patients undergoing CABG +/-valve repair or replacement. Patients were followed throughout the hospital stay and at a 30-day follow-up visit. Logistic regression models for pre-operative risk prediction were built for age-related clinical outcomes with high incidence including KDIGO-defined acute kidney injury (AKI), decline in eGFR ≥25% between pre-op and 30 days, and MACKE30, a composite endpoint of major adverse cardiac and kidney events at 30d. Results: AKI occurred in 19.9% of patients, persistent decline in kidney function at 30d occurred in 11.0%, and MACKE30 occurred in 13.4%. A network of six biomarkers of senescence (p16, p14, LAG3, CD244, CD28 and suPAR) were able to identify patients at risk for AKI (AUC 0.76), kidney decline at 30d (AUC 0.73), and MACKE30 (AUC 0.71). Comparing the top and bottom tertiles of senescence-based risk models, patients in the top tertile had 7.8 (3.3-8.4) higher odds of developing AKI, 4.5 (1.6-12.6) higher odds of developing renal decline at 30d, and 5.7 (2.1-15.6) higher odds of developing MACKE30. All models remained significant when adjusted for clinical variables. Patients with kidney function decline at 30d were largely non-overlapping and clinically distinct from those who experienced AKI, suggesting a different etiology. Typical clinical factors that predispose to AKI (e.g., age, CKD, surgery type) associated with AKI but not the 30d decline endpoint which was instead associated with new-onset atrial fibrillation. Conclusions: A six-member network of biomarkers of senescence, a fundamental mechanism of aging, can identify patients for risk of adverse kidney and cardiac events when measured pre-operatively.

Adult Para Testicular Spindle Cell Rhabdomyosarcoma: A Case Report From Pakistan.

Para testicular or intra-scrotal Rhabdomyosarcomas (RMS) are rare. The spindle cell variant of rhabdomyosarcoma is the least common variant among embryonal subtypes. They are mostly seen in childhood but rarely reported in adults. We present a case of a 56-year-old man who presented with a three-year history of painless left inguinoscrotal swelling, which he initially ignored and misinterpreted as an Inguinal hernia but later sought medical help upon a progressive increase in the size of the swelling. Clinically and radiologically, there was sparing of the left testis and spermatic cord with normal testicular tumor markers and no evidence of lymphadenopathy or metastasis. Surgical exploration was performed with complete excision of the mass, followed by histopathology and immunocytochemistry, confirming the diagnosis of spindle cell rhabdomyosarcoma. Prompt recognition, early diagnosis, and appropriate surgical treatment are the hallmarks of management. Regular and strict follow-up is needed due to the rarity of diagnosis.

Mitigation of greenhouse gas emissions from a red acidic soil by using magnesium-modified wheat straw biochar.

To mitigate greenhouse gas (GHG) emissions, different strategies have been proposed, including application of dolomite, crop straw and biochar, thus contributing to cope with the increasing global warming affecting the planet. In the current study, pristine wheat straw biochar (WBC) and magnesium (MgCl2.6H2O) modified wheat straw biochar (MWBC) were used. Treatments included control (CK), two WBC dosages (1% and 2.5%), and two MWBC doses (1% and 2.5%). After 90 days of incubation, WBC and MWBC improved the soil physiochemical properties, being more pronounced with increasing rates of biochar. MWBC2.5 significantly decreased microbial biomass carbon (MBC), while microbial biomass nitrogen (MBN) increased when both biochar materials (WBC1 and MWBC1) were applied at low rate. Compared to control soil, Urease and Alkaline phosphatase activities increased with the increasing rate of WBC and MWBC. The activities of dehydrogenase and ß-glucosidase decreased with the WBC and MWBC application, compared to CK. The fluxes of all the three GHGs evaluated (CO2, CH4 and N2O) decreased with time for both biochar amendments, while cumulative emission of CO2 increased by 58% and 45% for WBC, and by 54% and 41% for MWBC, as compared to CK. The N2O cumulative emissions decreased by 18 and 34% for WBC, and by 25 and 41% for MWBC, compared to CK, whereas cumulative methane emission showed non-significant differences among all treatments. These findings indicate that Mg-modified wheat straw biochar would be an appropriate management strategy aiding to reduce GHG emissions and improving the physiochemical properties of affected soils, and specifically of the red dry land soil investigated in the current work.

Identification of miRNA-mRNA Regulatory Modules Involved in Lipid Metabolism and Seed Development in a Woody Oil Tree (Camellia oleifera).

Tea oil camellia (Camellia oleifera), an important woody oil tree, is a source of seed oil of high nutritional and medicinal value that is widely planted in southern China. However, there is no report on the identification of the miRNAs involved in lipid metabolism and seed development in the high- and low-oil cultivars of tea oil camellia. Thus, we explored the roles of miRNAs in the key periods of oil formation and accumulation in the seeds of tea oil camellia and identified miRNA-mRNA regulatory modules involved in lipid metabolism and seed development. Sixteen small RNA libraries for four development stages of seed oil biosynthesis in high- and low-oil cultivars were constructed. A total of 196 miRNAs, including 156 known miRNAs from 35 families, and 40 novel miRNAs were identified, and 55 significantly differentially expressed miRNAs were found, which included 34 upregulated miRNAs, and 21 downregulated miRNAs. An integrated analysis of the miRNA and mRNA transcriptome sequence data revealed that 10 miRNA-mRNA regulatory modules were related to lipid metabolism; for example, the regulatory modules of ath-miR858b-MYB82/MYB3/MYB44 repressed seed oil biosynthesis, and a regulation module of csi-miR166e-5p-S-ACP-DES6 was involved in the formation and accumulation of oleic acid. A total of 23 miRNA-mRNA regulatory modules were involved in the regulation of the seed size, such as the regulatory module of hpe-miR162a_L-2-ARF19, involved in early seed development. A total of 12 miRNA-mRNA regulatory modules regulating growth and development were identified, such as the regulatory modules of han-miR156a_L+1-SPL4/SBP2, promoting early seed development. The expression changes of six miRNAs and their target genes were validated using quantitative real-time PCR, and the targeting relationship of the cpa-miR393_R-1-AFB2 regulatory module was verified by luciferase assays. These data provide important theoretical values and a scientific basis for the genetic improvement of new cultivars of tea oil camellia in the future.

Nanozymes for medical biotechnology and its potential applications in biosensing and nanotherapeutics.

Recent past years have witnessed the development of several artificial enzymes, using different materials to mimic natural enzymes with respect to their structure and functions. The nanozymes are nanomaterials possessing similar characteristics to the natural enzymes and have emerged recently as an innovative class of artificial enzymes. The nanozymes have got remarkable attention from the researchers and notable developments have been achieved owing to their unique properties compared with natural enzymes and classic artificial enzymes. In this regard, several nanomaterials have been scrutinized so far to mimic different natural enzymes for wider applications ranging from imaging, sensing, water treatment, pollutant removal, and therapeutics. The applications of nanozymes in biomedicine research are fast-growing and various nanozymes have been implicated in diagnostic medicine, targeted cancer therapy. Such abilities make them an appropriate alternative for the development of affordable, sustainable and safe diagnostic as well as therapeutic agents.

Anti-angiogenesis Potential of Phytochemicals for the Therapeutic Management of Tumors.

The role of angiogeneses during the growth and progression of tumors is well documented. Likewise, a balance is generally maintained between the cellular proliferation and the apoptosis, therefore, the tumors can persist for years in a dormant phase. During the past few years, many hypotheses have been proposed relating to the importance of tumor angiogenesis for the development and spread of tumors and preventive or therapeutic capacity of angiogenesis inhibitors as a potential target for controlling the growth of cancerous tissue. The antiangiogenic based therapeutic approaches are considered as the most promising method for the control of tumors, as this therapeutic approach is less likely to attain the drug resistance. Further, the tumor vasculature is an important prognostic marker that can independently predict the pathological stages as well as the metastatic potential of tumors. Various biologically active phytochemicals have been extracted from the dietary sources and the plants that have engaged the scientist and pharmaceutical industries around the globe. The antioxidant, antiinflammatory, anti-proliferative and anti-angiogenic potential of these bioactive phytochemicals is evident from the in vitro studies using cell lines and investigations involving the animal models. The present review is focused on the promising role of anti-angiogenesis-based therapies for the management of tumors and the recent developments relating to the interplay of phytochemicals and angiogenesis for the suppression of tumor cells.

Quorum Sensing Interfering Strategies and Their Implications in the Management of Biofilm-Associated Bacterial Infections

Abstract The bacterial species employ various types of molecular communication systems recognized as quorum sensing for the synchronization of differential gene expression to regulate virulence traits and biofilm formation. A variety of quorum sensing inhibitors; molecules that interfere with quorum sensing among bacteria have been examined which can block the action of autoinducers. Moreover, the studies have scrutinized various enzymes for their quorum quenching activity resulting in the degradation of signaling molecules or blocking of gene expression. So far, the studies have found that these approaches are not only capable to reduce the pathogenicity and biofilm formation but also resulted in increased bacterial susceptibility to antibiotics and bacteriophages. The effectiveness of these strategies has been validated in different animal models and it seems that these practices will be transformed in near future to develop the medical devices including catheters, implants, and dressings for the prevention of bacterial infections. Although many of these approaches are still in the research stage, the increasing library of quorum quenching molecules and enzymes will open innovative perspectives for the development of antibacterial approaches which will extend the therapeutic arsenal against the pathogenic bacterial species.

Impact of Microbiological Organism Type on Surgically Managed Endocarditis.

BACKGROUND: This study describes the impact of organism and valve type on surgically managed infective endocarditis (IE) from The Society of Thoracic Surgeons (STS) database. We developed a risk model for surgically managed endocarditis that includes the microbiological organism. METHODS: The STS database was queried for adult patients with surgically managed endocarditis from July 1, 2011, to June 30, 2016. Outcomes were compared based on (1) causative microbiological organism, (2) valve type (native vs prosthetic), and (3) endocarditis on the right (tricuspid) vs left (mitral, aortic) sides. Univariate and risk adjusted models were developed with odds ratios for mortality for each organism type referenced against Streptococcus. RESULTS: The study population included 21,388 operations (93%) for left-sided IE and 1698 (7%) for right-sided IE. Streptococcus (28%) and Staphylococcus (27%) were the most common infecting organisms, followed by Enterococcus (11%). After multivariate adjustment, microbiological organism type was significantly associated with operative mortality for patients with left-sided endocarditis, with an adjusted odds ratio of 2.9 for fungal, 1.4 for Staphylococcus, and 1.3 for culture-negative vs Streptococcus. For right-sided endocarditis, there were no differences in outcomes by organism type. Left-sided prosthetic valve endocarditis had a higher operative mortality than left-sided native valve endocarditis (12% vs 8%, P < .001). In contrast, surgery for right-sided endocarditis carried lower operative mortality, with no mortality difference between prosthetic valve endocarditis and native valve endocarditis (5% vs 4%, P = .6). CONCLUSIONS: Organism type influences the operative mortality for left-sided endocarditis. Surgery for left-sided and prosthetic valve endocarditis is associated with higher operative mortality. Risk adjustment for operative outcomes in endocarditis may need to account for microbiological organism type.

Anticancer, antithrombotic, antityrosinase, and anti-α-glucosidase activities of selected wild and commercial mushrooms from Pakistan.

Mushrooms have been accepted as nutraceutical foods because of their high nutritional and functional values. They have also gained interest due to their medicinal properties, economic importance, and organoleptic merit. In this study, wild Ganoderma lucidum and four commercial mushrooms, that is, Pleurotus ostreatus, Volvariella volvacea, Hericium erinaceus, and Lentinus edodes from Pakistan were screened for their biological activities such as anticancer, antityrosinase, anti-α-glucosidase, and antithrombotic activities from their methanol, ethanol, and water extracts. Enzyme inhibition assay showed that selected mushrooms are potent inhibitors with %age inhibition ranging from 19.00% to 80.91%, and 32.85% to 83.38% for tyrosinase and α-glucosidase, respectively. The best tyrosinase inhibition was shown by P. ostreatus whereas L. edodes was found best as α-glucosidase inhibitor. These mushrooms were tested against cancer cell lines including HT-29 colon and H-1299 lungs carcinoma cell lines. G. lucidum showed 29% and 24% viability of cells against HT-29 and H-1299 cell lines, respectively. This antiproliferative effect was in dose-dependent manner, and the maximum inhibition was observed at 200 µg/ml. Mushrooms extracts were also found effective against clot lysis. The percentage of clot lysis was in the range of 27%-29%. The research would provide knowledge to the people of Pakistan about the importance of locally available commercial mushrooms and wild mushrooms for health improvement and prevention against different kinds of diseases.

Identification of a Selective SIRT2 Inhibitor and Its Anti-breast Cancer Activity.

SIRT2 is a member of the human sirtuin family of proteins and possesses nicotinamide adenine dinucleotide (NAD)-dependent lysine deacetylase activity. SIRT2 has been involved in various cellular processes including gene transcription, genome constancy, and the cell cycle. In addition, SIRT2 is deeply implicated in diverse diseases including cancer. In this study, we identified a small molecule inhibitor of SIRT2 with a structure different from known SIRT2 inhibitors by screening from a chemical library. The hit compound showed a high selectivity toward SIRT2 as it only inhibited SIRT2, and not other sirtuins including SIRT1 and SIRT3 or zinc-dependent histone deacetylases (HDACs) including HDAC1 and HDAC6, in vitro. The compound increased the acetylation level of eukaryotic translation initiation factor 5A (eIF5A), a physiological substrate of SIRT2, and reduced cell viability of human breast cancer cells accompanied with a decrease in c-Myc expression. These results suggest that the compound is cellular effective and has potential for development as a therapeutic agent against breast cancers by specific inhibition of SIRT2.

Concomitant Thoracic Aortobifemoral Bypass With Left Ventricular Assist Device Implantation.

Improved quality of life for patients after left ventricular assist device (LVAD) implantation can be greatly limited by peripheral vascular disease even if heart failure symptoms are resolved by LVAD support. We present a case of concomitant thoracic aortobifemoral bypass and LVAD implantation in a patient with ischemic cardiomyopathy, severe peripheral vascular disease, and multiple previous failed revascularization attempts. In this patient, we used the LVAD outflow to provide the inflow to the femoral artery bypass graft. This graft has remained patent at a 2-year follow-up, without claudication symptoms. Performing concomitant major vascular operations safely and successfully is feasible in patients with LVADs. Quality of life after ventricular assist device placement can be limited by vascular disease, but it can be markedly improved after vascular surgical intervention.

Trans-aortic Alfieri stitch at the time of septal myectomy for hypertrophic obstructive cardiomyopathy.

BACKGROUND: Systolic anterior motion (SAM) of the mitral valve, left ventricular outflow tract (LVOT) obstruction, and mitral regurgitation (MR) are known adverse outcomes that can occur after septal myectomy for hypertrophic obstructive cardiomyopathy. The objective of this study was to describe outcomes of a surgical technique to prevent these complications. METHODS: We have adopted a technique where we place an Alfieri stitch in the mitral valve through the aortotomy while performing septal myectomy. A retrospective review was performed and outcomes associated with this technique were noted. RESULTS: Twenty-four patients underwent septal myectomy and mitral valve repair using this technique. Mean age was 57 ± 10 years. Twenty patients were in class III/IV heart failure, and all had documented SAM. Mean LVOT gradient improved from 78 ± 48 mmHg preoperatively to 19 ± 20 mmHg after myectomy (p < 0.001). No patients had postoperative SAM, and no patients required a second aortic crossclamping for mitral repair. Seventeen of 19 patients with ≥mild MR had improvement in MR. During follow-up, 16 patients had no/trivial MR, seven had mild MR, and one had moderate MR. The mean postoperative mitral gradient was 4.5 ± 3.0 mmHg. Thirteen patients had postoperative complications including one death in a patient who developed a ventricular septal defect. CONCLUSIONS: Trans-aortic Alfieri stitch placement during septal myectomy is feasible in most cases as an additional tool to improve MR and minimize SAM. This technique may have a role in addressing mitral disease, such as a long anterior leaflet or fibrotic mitral valve, at the time of myectomy without the need for left atriotomy for mitral exposure.

Gender and Cardiothoracic Surgery Training: Specialty Interests, Satisfaction, and Career Pathways.

BACKGROUND: The cardiothoracic surgical workforce is changing. Although 5% of practicing surgeons are women, 20% of current cardiothoracic surgery residents are women. The purpose of this study was to evaluate the influence of gender on specialty interest, satisfaction, and career pathways of current residents. METHODS: Responses to the mandatory 2015 Thoracic Surgery Residents Association/Thoracic Surgery Directors Association in-training examination survey taken by 354 residents (100% response rate) were evaluated. The influence of gender was assessed with the use of standard univariate analyses. RESULTS: Women accounted for 20% of residents, and the percentage did not vary with postgraduate year or program type (traditional versus integrated). Although no differences were found between the genders related to specialty interest, academic versus private practice career, or pursuit of additional training, women were more likely to pursue additional training in minimally invasive thoracic surgery (10% versus 2.5%, p = 0.001) and less likely to perform research in their careers (65% versus 88%, p = 0.043). Although women were equally satisfied with their career choice, had similar numbers of interviews and job offers, and felt equally prepared for their boards, graduating women felt less prepared technically (77% versus 90%, p = 0.01) and for practicing independently (71% versus 87%, p = 0.01). Women were less likely to be married (26% versus 62%, p < 0.001) and have children (19% versus 49%, p < 0.001). CONCLUSIONS: Although career satisfaction and specialty interest were similar between the genders, women were less likely to intend to perform research during their careers despite similar previous research experience. Women also demonstrated lower rates of marriage and childbearing compared with their male counterparts.

The Future of the Academic Cardiothoracic Surgeon: Results of the TSRA/TSDA In-Training Examination Survey.

BACKGROUND: Traditionally cardiothoracic residents spent dedicated research time during general surgery equipping them for a potential academic career. Recent changes in training paradigms, including integrated programs that may not include research time, could affect the development of future academic cardiothoracic surgeons. METHODS: Responses to the 2015 Thoracic Surgery Directors' Association/Thoracic Surgery Residents' Association survey accompanying the in-training examination taken by current cardiothoracic surgery residents were analyzed. Three hundred fifty-four residents were surveyed with a response rate of 100%, although one was excluded from the analysis because of inconsistencies in responses. Statistical analysis included χ(2), Fisher's exact test, and multinomial logistic regression with significance set at a probability value of 0.05. RESULTS: Two hundred sixty-seven of 353 residents (76%) intended on performing research as part of their careers. Integrated residents as opposed to traditional residents (85% versus 69%; p = 0.003), males (78% versus 65%; p = 0.02), those pursuing additional training (85% versus 69%; p = 0.003), and those interested in academic careers (93% versus 33%; p < 0.001) were more likely to pursue research. Differences were also noted in specialty interest, with congenital and heart failure specialties most likely to pursue research careers (92% and 100%, respectively; p < 0.05). Residents intending on research careers were more likely to have had previous research experience, and the most common type of intended research was clinical outcomes (78%). On multinomial logistic regression, previous clinical outcomes research and academic practice were identified as predictors of a research career (odd ratios of 9.7 and 4.1, respectively; each p < 0.05). CONCLUSIONS: The majority of residents plan on pursuing research during their careers. Previous research experience appears to be a key determinant as well as specialty interest.

Characterizing the Operative Experience of Cardiac Surgical Trainees: What Are Residents Really Doing in the Operating Room?

BACKGROUND: The present study aimed to describe and compare the operative experience of cardiothoracic surgical residents for basic and advanced cardiac surgical procedures. METHODS: Data were obtained from the 2015 Thoracic Surgery Directors Association Survey administered to all thoracic surgical residents taking the yearly In-Service Training Examination (n = 356). Residents were asked whether they routinely served as the operative surgeon on various cardiac operations and operative tasks. Results were stratified by postgraduate year (PGY), residency type, and primary career interest. RESULTS: The survey response rate was 100%. Considering all training pathways, only 2 of 13 cardiac operations surveyed were routinely performed by graduating chief residents as the operative surgeon: coronary artery bypass grafting (CABG; 92%) and aortic valve replacement (AVR; 88%). Off-pump CABG, minimally invasive mitral valve operation, and transcatheter aortic interventions were infrequently (<30% of the time) performed by graduating residents as the operative surgeon. These results were similar when residents with a career interest in general thoracic surgery were excluded from the analysis. For the operative progression of integrated 6-year (I-6) residents, most began to routinely cannulate for cardiopulmonary bypass, perform proximal coronary anastomoses, and harvest the mammary artery during PGY3. The majority (>50%) of I-6 residents performed CABG as the operative surgeon by PGY4. CONCLUSIONS: There is pronounced heterogeneity in the cardiac operative experience of cardiothoracic surgical residents in the United States, with only CABG and AVR routinely performed by graduating residents as the operative surgeon. This heterogeneity may lead to insufficient training in certain procedures for many graduates.

Prolonged postoperative respiratory support after proximal thoracic aortic surgery: Is deep hypothermic circulatory arrest a risk factor?

PURPOSE: In addition to the pulmonary risks associated with cardiopulmonary bypass, thoracic aortic surgery using deep hypothermic circulatory arrest (DHCA) may subject the lungs to further injury. However, this topic has received little investigation to date. MATERIALS AND METHODS: A prospective cohort review was performed on all patients undergoing proximal thoracic aortic surgery with (n = 478) and without (n = 135) DHCA between July 2005 and February 2013 at a single institution. The primary outcome was prolonged postoperative respiratory support (PPRS), defined as any of the following: >1 day of mechanical ventilation at either fraction of inspired oxygen >0.4 and/or positive end-expiratory pressure >5 mm Hg, >2 days of supplemental O2 requirement of at least 2.5 L/min, or discharge with new O2 requirement. Independent risk factors for PPRS were identified using multivariable logistic regression. RESULTS: Postoperative respiratory support was required in 100 patients (20.9%) with and 30 patients (22.2%) without DHCA (P = .74). Independent predictors of PPRS after proximal aortic surgery included the following: age, diabetes, history of stroke, preoperative creatinine, American Society of Anesthesiologists class 4, redo-sternotomy, total arch replacement, and transfusion requirement. Use of DHCA was not an independent risk factor for PPRS in the entire cohort. Subanalysis of only DHCA patients revealed that longer DHCA times were independently associated with PPRS. CONCLUSIONS: Prolonged postoperative respiratory support is common after proximal aortic surgery. The use of DHCA was not associated with this complication in the overall cohort, although longer DHCA times were predictive when only the subset of patients undergoing DHCA was analyzed. Knowledge of the risk factors for PPRS after proximal aortic surgery should improve preoperative risk stratification and postoperative management of these patients.