High-Sensitivity Troponin I after Cardiac Surgery and 30-Day Mortality

BACKGROUND

Consensus recommendations regarding the threshold levels of cardiac troponin elevations for the definition of perioperative myocardial infarction and clinically important periprocedural myocardial injury in patients undergoing cardiac surgery range widely (from >10 times to ≥70 times the upper reference limit for the assay). Limited evidence is available to support these recommendations.

METHODS

We undertook an international prospective cohort study involving patients 18 years of age or older who underwent cardiac surgery. High-sensitivity cardiac troponin I measurements (upper reference limit, 26 ng per liter) were obtained 3 to 12 hours after surgery and on days 1, 2, and 3 after surgery. We performed Cox analyses using a regression spline that explored the relationship between peak troponin measurements and 30-day mortality, adjusting for scores on the European System for Cardiac Operative Risk Evaluation II (which estimates the risk of death after cardiac surgery on the basis of 18 variables, including age and sex).

RESULTS

Of 13,862 patients included in the study, 296 (2.1%) died within 30 days after surgery. Among patients who underwent isolated coronary-artery bypass grafting or aortic-valve replacement or repair, the threshold troponin level, measured within 1 day after surgery, that was associated with an adjusted hazard ratio of more than 1.00 for death within 30 days was 5670 ng per liter (95% confidence interval [CI], 1045 to 8260), a level 218 times the upper reference limit. Among patients who underwent other cardiac surgery, the corresponding threshold troponin level was 12,981 ng per liter (95% CI, 2673 to 16,591), a level 499 times the upper reference limit.

CONCLUSIONS

The levels of high-sensitivity troponin I after cardiac surgery that were associated with an increased risk of death within 30 days were substantially higher than levels currently recommended to define clinically important periprocedural myocardial injury. (Funded by the Canadian Institutes of Health Research and others; VISION Cardiac Surgery ClinicalTrials.gov number, NCT01842568.).

Management of acute type A intramural hematoma: upfront surgery or individualized approach? A retrospective analysis and meta-analysis

Background

Management of acute type A intramural hematoma (IMH) is a controversial topic. In our study, we aim to analyze the survival outcomes in local patients with acute type A IMH and a meta-analysis on survival in type A IMH treated medically versus surgically was performed.

Methods

From 2014 to 2019, 65 patients with acute type A IMH were selected for analysis. Primary outcome of interest was 1 year all cause survival. The rate of aortic-related events in the medical group was evaluated. PubMed and Embase were searched for meta-analysis.

Results

The mean age of our cohort was 61.7±9.7 years. Of the 65 patients, 40% had emergency operation. Overall 1-year survival was 96.9%. The 1-year survival was 94.9% for the medical group. 46.2% of the medical group required aortic intervention at a mean duration of 191±168 days. Maximal aortic diameter (MAD) ≥45 mm was predictive of aortic-related events in the medical group (OR: 7.0; 95% CI, 1.7-29.4; P=0.008). For the meta-analysis, 21 studies were identified, and 900 patients were included. Emergent surgery was associated with improved survival in type A IMH (OR: 0.76; 95% CI, 0.29-1.97, P=0.58; I²=27%).

Conclusions

The 1-year survival after type A IMH was promising, regardless of approach. The conservative-first approach was found to be safe & feasible, and upfront surgery remained the management of choice in general. Patients with MAD ≥45 mm was associated with subsequent aortic intervention in the medical-first group.

Ambient fine particulate matter inhibits 15-lipoxygenases to promote lung carcinogenesis

Background

Epidemiological observations have demonstrated that ambient fine particulate matter with d_p < 2.5 μm (PM_2.5) as the major factor responsible for the increasing incidence of lung cancer in never-smokers. However, there are very limited experimental data to support the association of PM_2.5 with lung carcinogenesis and to compare PM_2.5 with smoking carcinogens.

Methods

To study whether PM_2.5 can contribute to lung tumorigenesis in a way similar to smoking carcinogen 4-methylnitrosamino-l-3-pyridyl-butanone (NNK) via 15-lipoxygenases (15-LOXs) reduction, normal lung epithelial cells and cancer cells were treated with NNK or PM_2.5 and then epigenetically and post-translationally examined the cellular and molecular profiles of the cells. The data were verified in lung cancer samples and a mouse lung tumor model.

Results

We found that similar to smoking carcinogen NNK, PM2.5 significantly enhanced cell proliferation, migration and invasion, but reduced the levels of 15-lipoxygenases-1 (15-LOX1) and 15-lipoxygenases-2 (15-LOX2), both of which were also obviously decreased in lung cancer tissues. 15-LOX1/15-LOX2 overexpression inhibited the oncogenic cell functions induced by PM2.5/NNK. The tumor formation and growth were significantly higher/faster in mice implanted with PM2.5- or NNK-treated NCI-H23 cells, accompanied with a reduction of 15-LOX1/15-LOX2. Moreover, 15-LOX1 expression was epigenetically regulated at methylation level by PM2.5/NNK, while both 15-LOX1 and 15-LOX2 could be significantly inhibited by a set of PM2.5/NNK-mediated microRNAs.

Conclusion

Collectively, PM2.5 can function as the smoking carcinogen NNK to induce lung tumorigenesis by inhibiting 15-LOX1/15-LOX2.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1380-z) contains supplementary material, which is available to authorized users.

EGFR-AS1/HIF2A regulates the expression of FOXP3 to impact the cancer stemness of smoking-related non-small cell lung cancer

Background:

Early data showed that FOXP3 could induce epithelial-mesenchymal transition by stimulating the Wnt/β-catenin signaling pathway in non-small cell lung cancer (NSCLC). However, how the expression of FOXP3 is regulated in NSCLC remains unknown. We thus explored the impacts of the long noncoding RNA EGFR antisense RNA 1 (EGFR-AS1) and hypoxia-inducible factor-2A (HIF2A) on FOXP3 expression and the cancer stemness of NSCLC.

Methods:

Lung tissues samples from 87 patients with NSCLC and two NSCLC cell lines were used in this study. The regulation of FOXP3 and lung cancer cell stemness by EGFR-AS1 and HIF2A was determined at molecular levels in NSCLC tissue samples and cultured cells in the presence/absence of the smoking carcinogen, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (also known as nicotine-derived nitrosamine ketone). The results were confirmed in tumor xenograft models.

Results:

We found that NNK decreased the expression of EGFR-AS1 in the long term, but increased the expression of HIF2A and FOXP3 to stimulate lung cancer cell stemness. EGFR-AS1 significantly inhibited FOXP3 expression and NSCLC cell stemness, whereas HIF2A obviously promoted both. The enhancement of lung cancer stemness by FOXP3 was, at least partially, via stimulating Notch1, as the inhibition of Notch1 could markedly diminish the effect of FOXP3.

Conclusions:

FOXP3, the expression of which is under the fine control of EGFR-AS1, is a critical molecule that promotes NSCLC cancer cell stemness through stimulating the Notch1 pathway.

Redo tricuspid valve operation in patients with 1st-generation mitral prostheses

Background In patients with remarkably enlarged cardiac chambers and history of implantation of older types of mitral valve prosthesis, the considerations for reoperative tricuspid valve surgery are not limited to the risks of sternal reentry but also include the dilemma of whether to carry out prophylactic replacement of the normal functioning but outdated prosthesis or leave it in situ. Methods We reviewed our surgical strategy and postoperative 5-year follow-up findings in two patients who underwent redo tricuspid surgery 3 to 4 decades after mechanical mitral valve replacement. Both patients presented with significant symptoms of progressive right heart failure due to severe tricuspid regurgitation, despite optimal medical therapy. Results We found the beating-heart approach to be an effective and safe method for redo tricuspid surgery. Both first-generation mitral mechanical prostheses were not replaced and have remained well functional upon the patients' postoperative 5-year follow-up, respectively. Conclusion For patients with normal functioning first-generation mechanical mitral prostheses, whether to prophylactically replace the prosthesis should be based on an individualized risk-benefit analysis.

Novel method for rapid identification of micropapillary or solid components in early-stage lung adenocarcinoma

OBJECTIVE

Sublobar resection may be insufficient for early-stage lung adenocarcinoma with micropapillary or solid components because of the associated higher incidence of locoregional recurrence. This study sought to establish a novel method for rapidly identifying their presence to facilitate decision making for sublobar resection.

METHODS

Antibody arrays of adhesion and apoptosis molecules were applied for adenocarcinomas with or without micropapillary/solid components to identify differentially expressed proteins. A semi-dry dot-blot system that visualizes the presence of target proteins was used to determine the presence of micropapillary or solid components in a prospective cohort of patients with clinical stage I who underwent operation. Sensitivity and specificity were calculated by comparing semi-dry dot-blot results with pathologic examinations.

RESULTS

Insulin-like growth factor-binding protein 2 and P-cadherin were found more frequently in the micropapillary or solid positive group, and these were used as the target proteins in the semi-dry dot-blot system for detection of micropapillary or solid components. A total of 68 nodules with a mean size of 2.3 ± 0.7 cm, including 13 (19.1%) with a micropapillary and 20 (29.4%) with a solid pattern, were recruited. Micropapillary or solid (+) lesions were more likely to have lymph node upstaging, greater diameter, and higher maximum standardized uptake value. The specificity and sensitivity for detecting the minor presence of micropapillary or solid component using the semi-dry dot-blot method were 94.4% (95% confidence interval, 81.3-99.3) and 65.6% (95% confidence interval, 46.8-81.4), respectively. The average test duration was 26.9 ± 2.5 minutes.

CONCLUSIONS

Detecting insulin-like growth factor-binding protein 2 and P-cadherin via the semi-dry dot-blot method could identify micropapillary or solid components in early-stage lung adenocarcinoma in a short processing time.

Video-assisted thoracic surgery for tiny pulmonary nodules with real-time image guidance in the hybrid theatre: the initial experience

Background

Localization of tiny lung nodules during video-assisted thoracic surgery (VATS) resection can be challenging. Real-time image-guided hookwire localization of the target lesions immediately followed by VATS lung resection in the hybrid operating theatre setting is an emerging approach.

Methods

We retrospectively reviewed our experience with this form of hybrid operating theatre image-guided VATS (iVATS) for lung nodules 1.5 cm or less, or soft in consistency. These patients were compared with matched cohort who received standard hookwire localization in the radiology department.

Results

From February 2014 to September 2017, lung nodules of indeterminate nature in 32 consecutive patients with mean size 9.1±4.6 mm underwent iVATS. All were accurately localized by hookwire and successfully resected. There was no postoperative mortality. There were 21 (66%) malignant lesions, all with adequate resection margins. Major outcomes were compared with a comparable cohort of 8 patients who received standard hookwire localization and VATS (sVATS) performed at separate departments operation suites. sVATS groups has significantly longer 'at-risk' period for pneumothorax progression and hookwire dislodgement (109.5±57.1 minutes for sVATS vs. 41.1±15.0 minutes for iVATS, P=0.011), and a higher risk of hookwire dislodgement (25% for sVATS vs. 0 for iVATS, P=0.036).

Conclusions

Real-time image-guided hookwire localization in the hybrid theatre setting is an effective facilitator of VATS resection of tiny lung nodules in selected patients, and may have added advantages in terms of safety and localization accuracy over the conventional sVATS method.

FOXP3 promotes tumor growth and metastasis by activating Wnt/β-catenin signaling pathway and EMT in non-small cell lung cancer

Background

The role of cancer cell FOXP3 in tumorigenesis is conflicting. We aimed to study FOXP3 expression and regulation, function and clinical implication in human non-small cell lung cancer (NSCLC).

Methods

One hundred and six patients with histologically-confirmed NSCLC who underwent surgery were recruited for the study. Tumor samples and NSCLC cell lines were used to examine FOXP3 and its related molecules. Various cell functions related to tumorigenesis were performed. In vivo mouse tumor xenograft was used to confirm the in vitro results.

Results

NSCLC patients with the high level of FOXP3 had a significant decrease in overall survival and recurrence-free survival. FOXP3 overexpression significantly induced cell proliferation, migration, and invasion, whereas its inhibition impaired its oncogenic function. In vivo studies confirmed that FOXP3 promoted tumor growth and metastasis. The ectopic expression of FOXP3 induced epithelial–mesenchymal transition (EMT) with downregulation of E-cadherin and upregulation of N-cadherin, vimentin, snail, slug, and MMP9. The oncogenic effects by FOXP3 could be attributed to FOX3-mediated activation of Wnt/β-catenin signaling, as FOXP3 increased luciferase activity of Topflash reporter and upregulated Wnt signaling target genes including c-Myc and Cyclin D1 in NSCLC cells. Co-immunoprecipitation results further indicated that FOXP3 could physically interacted with β-catenin and TCF4 to enhance the functions of β-catenin and TCF4, inducing transcription of Wnt target genes to promote cell proliferation, invasion and EMT induction.

Conclusions

FOXP3 can act as a co-activator to facilitate the Wnt-b-catenin signaling pathway, inducing EMT and tumor growth and metastasis in NSCLC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0700-1) contains supplementary material, which is available to authorized users.

Transcatheter aortic valve implantation: the transaortic approach

Background

Transcatheter aortic valve implantation has been established as a safe and effective treatment option for patients at high or prohibitive surgical risk. However, some patients may not be suitable for the transfemoral approach due to severe iliofemoral disease or aneurysmal disease of the thoracoabdominal aorta. The aim of this case series was to evaluate the feasibility and clinical outcomes of the transaortic approach.

Methods

From May 2015 to June 2016, 5 patients (mean age 78.4 ± 3.9 years) with severe symptomatic aortic stenosis underwent transaortic transcatheter aortic valve implantation after a heart team discussion. They were considered to be at high surgical risk and ineligible for the transfemoral approach due to iliofemoral or thoracoabdominal aortic disease.

Results

A CoreValve Evolut R was successfully deployed in all 5 patients. We performed 4 right mini-parasternal incisions and one J-incision partial sternotomy. None of the patients required permanent pacemaker implantation, one required reopening of the mini-parasternal incision for postoperative bleeding. Follow-up echocardiography one month after the procedure showed improvement in the mean aortic gradient (from 63.2 to 8.3 mm Hg) and aortic valve area (from 0.62 to 2.2 cm2). None of the patients had more than mild paravalvular leakage. There was no intraoperative or 30-day mortality.

Conclusion

Transaortic transcatheter aortic valve implantation is a safe and feasible option for patients with severe aortic stenosis who are considered unsuitable for transfemoral aortic valve implantation.

Risk prediction models for delirium in the intensive care unit after cardiac surgery: a systematic review and independent external validation

Numerous risk prediction models are available for predicting delirium after cardiac surgery, but few have been directly compared with one another or been validated in an independent data set. We conducted a systematic review to identify validated risk prediction models of delirium (using the Confusion Assessment Method-Intensive Care Unit tool) after cardiac surgery and assessed the transportability of the risk prediction models on a prospective cohort of 600 consecutive patients undergoing cardiac surgery at a university hospital in Hong Kong from July 2013 to July 2015. The discrimination (c-statistic), calibration (GiViTI calibration belt), and clinical usefulness (decision curve analysis) of the risk prediction models were examined in a stepwise manner. Three published high-quality intensive care unit delirium risk prediction models (n=5939) were identified: Katznelson, the original PRE-DELIRIC, and the international recalibrated PRE-DELIRIC model. Delirium occurred in 83 patients (13.8%, 95% CI: 11.2-16.9%). After updating the intercept and regression coefficients in the Katznelson model, there was fair discrimination (0.62, 95% CI: 0.58-0.66) and good calibration. As the original PRE-DELIRIC model was already validated externally and recalibrated in six countries, we performed a logistic calibration on the recalibrated model and found acceptable discrimination (0.75, 95% CI: 0.72-0.79) and good calibration. Decision curve analysis demonstrated that the recalibrated PRE-DELIRIC risk model was marginally more clinically useful than the Katznelson model. Current models predict delirium risk in the intensive care unit after cardiac surgery with only fair to moderate accuracy and are insufficient for routine clinical use.

Preemptive Aneurysm Sac Embolization for Thoracic Endovascular Aortic Repair With Inadequate Proximal Landing Zone

Thoracic endovascular aortic repair (TEVAR) offers a less invasive treatment for aortic arch aneurysms. Clinical challenges arise when there is inadequate proximal landing for zone 1 TEVAR, such that a median sternotomy with total aortic debranching is required before stent deployment. The chimney technique was reported as an alternative approach to stent the arch branches and avoid sternotomy, but it was still associated with considerable chance of a type IA endoleak. We report a case of aortic arch aneurysm with an inadequate proximal landing for zone 1 TEVAR that was treated with debranching of head and neck vessels followed by TEVAR and preemptive and targeted coil embolization of the arch aneurysmal sac. Postoperative computed tomography showed no significant endoleak, and the patient had an unremarkable recovery.

Mycotic aortic arch aneurysm coexistent with constrictive pericarditis: is surgery a dangerous resort?

An elderly man presented with fever and evidence of Salmonella infection, and was diagnosed to have coexisting constrictive pericarditis and mycotic aneurysm of the aortic arch. Pericardiectomy was performed under cardiopulmonary bypass with good result. To avoid deep hypothermic circulatory arrest, an aorto-brachiocephalic bypass, instead of total arch replacement, was performed. This was followed by a staged carotid-carotid bypass, thoracic endovascular stent graft placement. He was subsequently treated with prolonged antibiotics, and inflammatory marker normalized afterwards. He was last seen well 2 years after the operation. Follow-up computer tomography (CT) scan at 18 months post-op showed no evidence of endoleak or fistulation. Our case demonstrated that a hybrid treatment of open pericardiectomy and aortic debranching followed by thoracic endovascular stent graft placement is feasible and associated with satisfactory mid-term outcome.

Penetrating thoracic injury with retained foreign body: can video-assisted thoracic surgery take up the leading role in acute management?

Video-assisted thoracic surgery (VATS) is widely adopted in acute management of patient with thoracic trauma, but its use in penetrating thoracic injuries with retained foreign bodies were rarely reported. We described three of such cases using VATS as the first line approach. Identification of injuries, control of bleeders, clot evacuation, resection of damaged lung parenchyma and safe retrieval of foreign bodies were all performed via complete VATS within short operative time. Patient were uneventfully discharged during early post-operative period. We suggest that, for haemodynamically stable patients, VATS offers a safe and minimally-invasive alternative to conventional thoracotomy for penetrating thoracic injury with retained foreign bodies.

Hypoxemia associated with right-side cardiac tumor: right atrial lymphoma with patent foramen ovale

A 66-year-old man presented with acute type I respiratory failure, and was diagnosed to have a huge mass occupying the right atrium (RA) of the heart, with no evidence of pulmonary embolism. Intra-operative transesophageal echocardiogram identified a patent foramen ovale (PFO) with right-to-left shunt apart from a huge right atrial tumor arising from the atrioventricular groove. The tumor was debulked, and the patent foramen was closed. Patient had an uneventful recovery and WAS discharged on post-operative day 7. Pathology revealed diffuse large B-cell lymphoma (DLBCL). The patient was further treated with adjuvant chemotherapy and remained well 1 year after surgery. This case illustrates the importance of meticulous echocardiographic examination to look for any intracardiac shunts in the case of hypoxemia associated with a right-sided cardiac tumor. We advocate surgery as the most important initial management to maximize survival, as it allows correction of any hemodynamic sequelae, and simultaneous attainment of definite histological diagnosis for guidance of adjuvant therapy.

Mitral valve repair using a semirigid ring: patient selection and early outcomes

BACKGROUND

Commonly used complete mitral annuloplastic rings include saddle-shaped and semirigid rings, with no clear indication for either type. A semirigid ring may be preferred in patients whose native mitral saddle shape is well maintained. We present our experience of using semirigid rings for mitral valve repair.

METHODS

We routinely measured the annular height-to-commissural width ratio by 3-dimensional transesophageal echocardiography prior to mitral repair. We generally chose a semirigid (Memo 3D) ring in patients whose annular height-to-commissural width ratio was normal (≥ 15%). The same semirigid ring with an additional chordal guiding system (Memo 3D ReChord) was selected for patients with anterior leaflet or bileaflet pathology. Over an 18-month period, 66 patients with severe degenerative (n = 60) or functional (n = 6) mitral regurgitation had Memo 3D (n = 32) or Memo 3D ReChord (n = 34) rings implanted.

RESULTS

Postoperative 3-dimensional transesophageal echocardiography was completed in all patients (mean follow-up 7 ± 5 months). The majority of patients had no or mild residual mitral regurgitation; only two had moderate (2+) mitral regurgitation. There was no mortality at 30-days or on midterm follow-up.

CONCLUSIONS

Our series represents the first Asian clinical experience using the Memo 3D ReChord ring. Although the long-term durability of mitral repair with this type of semirigid annuloplastic ring warrants further validation, our current clinical data are encouraging.

Multimodality imaging assessment for Thoraflex hybrid total arch replacement

Conventionally, aortic pathologies involving the ascending, arch, and descending thoracic aorta are treated by a staged operation. The Thoraflex device is a composite 4-branched graft with a distal endovascular stent, which allows one-stage treatment of these pathologies. We describe our multimodality hybrid approach for total arch replacement using the Thoraflex device with the adjunct of intraoperative 3-dimensional transesophageal echocardiography, Endo-EYE endoscopy, and on-table aortography in a hybrid operating room. These multimodality assessments can ascertain adequate sealing of a distal aortic tear and proper opening of the endograft, and provide on-table functional assessment of false lumen hemodynamics. Early results are promising.

A randomized controlled trial of 2 protocols for weaning cardiac surgical patients receiving adaptive support ventilation

PURPOSE

This study aims to compare the effectiveness of weaning with adaptive support ventilation (ASV) incorporating progressively reduced or constant target minute ventilation in the protocol in postoperative care after cardiac surgery.

MATERIAL AND METHODS

A randomized controlled unblinded study of 52 patients after elective coronary artery bypass surgery was carried out to determine whether a protocol incorporating a decremental target minute ventilation (DTMV) results in more rapid weaning of patients ventilated in ASV mode compared to a protocol incorporating a constant target minute ventilation.

RESULTS

Median duration of mechanical ventilation (145 vs 309 minutes; P = .001) and intubation (225 vs 423 minutes; P = .005) were significantly shorter in the DTMV group. There was no difference in adverse effects (42% vs 46%) or mortality (0% vs 0%) between the 2 groups.

CONCLUSIONS

Use of a DTMV protocol for postoperative ventilation of cardiac surgical patients in ASV mode results in a shorter duration of ventilation and intubation without evidence of increased risk of adverse effects.

Antineoplastic effects of 15(S)-hydroxyeicosatetraenoic acid and 13-S-hydroxyoctadecadienoic acid in non-small cell lung cancer

BACKGROUND

Previous studies have shown that the levels of 15-lipoxygenase 1 (15-LOX-1) and 15-LOX-2 as well as their metabolites 13-S-hydroxyoctadecadienoic acid (13(S)-HODE) and 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) are significantly reduced in smokers with non-small cell lung carcinoma (NSCLC). Furthermore, animal model experiments have indicated that the reduction of these molecules occurs before the establishment of cigarette smoking carcinogen-induced lung tumors, and this suggests roles in lung tumorigenesis. However, the functions of these molecules remain unknown in NSCLC.

METHODS

NSCLC cells were treated with exogenous 13(S)-HODE and 15(S)-HETE, and then the ways in which they affected cell function were examined. 15-LOX-1 and 15-LOX-2 were also overexpressed in tumor cells to restore these 2 enzymes to generate endogenous 13(S)-HODE and 15(S)-HETE before cell function was assessed.

RESULTS

The application of exogenous 13(S)-HODE and 15(S)-HETE significantly enhanced the activity of peroxisome proliferator-activated receptor γ (PPARγ), inhibited cell proliferation, induced apoptosis, and activated caspases 9 and 3. The overexpression of 15-LOX-1 and 15-LOX-2 obviously promoted the endogenous levels of 13(S)-HODE and 15(S)-HETE, which were demonstrated to be more effective in the inhibition of NSCLC.

CONCLUSIONS

This study has demonstrated that exogenous or endogenous 13(S)-HODE and 15(S)-HETE can functionally inhibit NSCLC, likely by activating PPARγ. The restoration of 15-LOX activity to increase the production of endogenous 15(S)-HETE and 13(S)-HODE may offer a novel research direction for molecular targeting treatment of smoking-related NSCLC. This strategy can potentially avoid side effects associated with the application of synthetic PPARγ ligands.

Alveolar rhabdomyosarcoma of the anterior mediastinum with vessel invasion in a 4-month-old boy: a case report

Introduction

Alveolar rhabdomyosarcomas of the mediastinum in children are rarely reported. Multimodality therapy including chemotherapy, surgery and radiotherapy make up the backbone of the treatment of childhood rhabdomyosarcomas. Complete resection whenever achievable is an important prognostic factor. However, complete resection of tumors in the mediastinum often poses a unique challenge to thoracic surgeons due to their close proximity to important neurovascular structures. Complete resection may not always be possible and judicious peri-operative planning and preparation are required to avoid creating unnecessary surgical morbidities resulting in delay of adjuvant therapy.

Case presentation

A 4-month-old Chinese baby boy was presented to our hospital with stridor, shortness of breath and episodes of cyanosis. Imaging studies found an anterior mediastinal mass compressing the trachea and other neurovascular structures and he was diagnosed to have alveolar rhabdomyosarcoma. Our patient received upfront chemotherapy and subsequently open resection of the mass was attempted via median sternotomy. Intraoperatively, the mass had invaded into the great vessels, precluding a complete resection. Debulking surgery was performed instead and our patient received timely postoperative chemoradiotherapy.

Conclusions

We report a rare case of childhood alveolar rhabdomyosarcoma of the mediastinum with vascular invasion treated with chemoradiotherapy and debulking surgery. Complete resection was not possible due to the close proximity to the great vessels. Different surgical approaches to the mediastinum have been reported in adults and children alike. Regardless of the surgical access, the treatment of childhood rhabdomyosarcomas should be individualized, with careful balance between surgical clearance and surgical morbidity.

Estrogen receptor alpha promotes smoking-carcinogen-induced lung carcinogenesis via cytochrome P450 1B1

Smoking carcinogen N-nitrosamines such as 4-methylnitrosamino-l-3-pyridyl-butanone (NNK) require metabolic activation to exert their genotoxicity. The first activation step is mainly catalyzed by cytochrome P450 (CYP) family. Estrogen receptor α (ERα) plays a role in lung pathology. The association between them is unknown. In this study, we explored the relationship and function of CYP1B1 and ERα in NNK-induced lung tumorigenesis. CYP1B1 and ERα expression was analyzed in human lung cancer tissues and NNK-induced lung tumor of A/J mice. Cell lines NCI-H23 and NCI-H460 were employed to further study the responsible mechanisms using various cellular and molecular approaches. Our in vivo experiments demonstrated that CYP1B1 and ERα were over-expressed at the early stage of NNK-induced lung tumorigenesis. Microarray analysis found that ERα was involved in the extracellular-signal-regulated kinase (ERK)/MAPK pathway. NNK activated RAS/ERK/AP1 as it remarkably increased the levels of p-ERK, c-Fos, and c-Jun but inhibited multiple negative regulators of Ras/ERK/AP1, Pdcd4, Spry1, Spry2, and Btg2 through up-regulating miR-21. Both CYP1B1 siRNA and ERK-specific inhibitor U0126 suppressed NNK-mediated ERα up-regulation, suggesting that ERα was downstream of CYP1B1 and ERK. ERK inactivation led to the accumulation of CYP1B1, indicating that CYP1B1 was upstream of ERK activation. Inhibition of ERK or ERα decreased NNK-induced cell proliferation. Blockage of CYP1B1 or ERα induced apoptosis of lung cancer cells. Collectively, NNK-mediated ERα induction is via CYP1B1 and ERK and contributes to the lung carcinogenesis. The inhibition of CYP1B1, ERK, or ERα may arrest the lung cancer cell growth, implicating a pivotal strategy for the treatment of lung cancer.

KEY MESSAGES

Smoking carcinogen NNK requires metabolic activation to exert their genotoxicity. CYP1B1 is the enzyme to catalyze NNK. NNK activates CYP1B1 and ERK to induce ERα. Inhibition of CYP1B1, ERK, or ERα arrests the lung cancer cell growth.

Hybrid Antegrade Thoracic Aortic Stenting via a Temporary Ascending Aortic Graft Conduit for a Patient with Poor Peripheral Vascular Access

In patients with poor peripheral vascular access, thoracic aortic stenting procedures can be technically very challenging. Antegrade aortic stent deployments during concomitant open ascending and arch procedures are well described, but the issue of long endovascular catheters and wires may make such an approach difficult and awkward. We describe a novel hybrid method involving a temporary graft conduit to the ascending aorta which is brought caudal toward the foot of the table to facilitate antegrade deployment of the thoracic stent graft.

Defeating the pores of Kohn

In the treatment of emphysema with an endobronchial valve, entire lobar treatment is important in achieving adequate atelectasis. This case illustrates that without treatment of the entire lobe, it can fail to collapse even after several years, leading to treatment failure. Intralobar collateral ventilation through the pores of Kohn is demonstrated in this case, as endobronchial valve blockage of the remaining patent anterior segment resulted in the desired atelectasis and significant improvements in pulmonary function.

Does repeat thymectomy improve symptoms in patients with refractory myasthenia gravis?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was: Does repeat thymectomy improve symptoms in patients with refractory myasthenia gravis after thymectomy? A total of 189 papers were found using the reported search, of which seven represented the best evidence to answer the clinical question. The outcome measures included operative mortality and morbidity, as well as long-term remission rate. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All the studies were small (4-21 patients), retrospective, single institutional case series. There was considerable heterogeneity in the studies. The interval between the first and second operation ranged from less than a year to over 10 years. The operative approach of the initial operation included transcervical, trans-sternal and substernal approaches. The maximal medical therapy received by the patients prior to reoperation varied from anticholinesterase alone to cytotoxic therapy and regular plasmapheresis. The severity of symptoms ranged from Osserman Class IIa to V. The operative approach to re-thymectomy included resternotomy, thoracoscopy and a combination of both. There was no perioperative mortality. One study reported injury to the innominate vein at resternotomy in 3 (14.3%) patients. One study reported myasthenic crisis in 2 patients in the postoperative period. Only one study reported complete remission in 2 patients. In general, however, 52-95% of patients reported some improvement. There was no consistent, objective measure of improvement in these studies. We conclude that repeat thymectomy for patients with refractory myasthenia gravis after previous thymectomy is safe especially for patients whose first procedure was transcervical. Complete remissions are rare but, in these small series, 60-70% of patients report improvement. Clinical improvement appears to be associated with the presence of residual thymic tissue at the second operation, but these cannot be reliably identified on preoperative imaging. Patient selection remains driven by symptoms.

Aortic arch/elephant trunk procedure with Sienna(TM) graft and endovascular stenting of thoraco-abdominal aorta for treatment of complex chronic dissection

Aneurismal dilatation of the remaining thoracic aorta after ascending aortic interposition grafting for type 'A' aortic dissection is not uncommon. For such complex cases, one treatment option is total arch replacement and elephant trunk procedure with the Sienna(TM) collared graft (Vascutek, Inchinnan, UK) technique followed by a staged thoracic endovascular aortic repair (TEVAR). The video illustrates our technique in a 56-year-old man with an extensive aortic arch and descending thoracic aortic dissecting aneurysm. For the 'open' procedure femoral arterial and venous cannulation was used along with systemic cooling and circulatory arrest at 22 °C. Upon circulatory arrest, the aortic arch was incised and antegrade cerebral perfusion achieved via selective cannulation to the right brachiocephalic and left common carotid artery, keeping flow rates at 10-15 mL/kg/min and perfusion pressure at 50-60 mmHg. Arch replacement with an elephant trunk component was then performed and after completion of the distal aortic anastomosis antegrade perfusion via a side-arm in the graft was started and the operation completed using a variation of the 'sequential' clamping technique to maximize cerebral perfusion. The second endovascular stage was performed two weeks after discharge. Two covered stents were landing from the elephant trunk to the distal descending thoracic aorta, to secure the distal landing a bare stent of was placed to cover the aorta just distal to the origin of the celiac axis. The left subclavian artery was embolised with fibre coils. Post TEVAR angiogram showed no endoleak Although re-operative total arch replacement and elephant trunk procedure and subsequent TEVAR remained a challenging procedure, we believe excellent surgical outcome can be achieved with carefully planned operative strategy.

A meta-analysis of deep hypothermic circulatory arrest alone versus with adjunctive selective antegrade cerebral perfusion

INTRODUCTION

Recognizing the importance of neuroprotection in aortic arch surgery, deep hypothermic circulatory arrest (DHCA) now underpins operative practice as it minimizes cerebral metabolic activity. When prolonged periods of circulatory arrest are required, selective antegrade cerebral perfusion (SACP) is supplemented as an adjunct. However, concerns exist over the risks of SACP in introducing embolism and hypo- and hyper-perfusing the brain. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA alone or DHCA + SACP as neuroprotection strategies.

METHODS

Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA alone with DHCA + SACP. Data were extracted and meta-analyzed according to pre-defined clinical endpoints.

RESULTS

Nine comparative studies were identified in the present meta-analysis, with 648 patients employing DHCA alone and 370 utilizing DHCA + SACP. No significant differences in temporary or permanent neurological outcomes were identified. DHCA + SACP was associated with significantly better survival outcomes (P=0.008, I(2)=0%), despite longer cardiopulmonary bypass time. Infrequent and inconsistent reporting of other clinical results precluded analysis of systemic outcomes.

CONCLUSIONS

The present meta-analysis indicate the superiority of DHCA + SACP in terms of mortality outcomes.

Quantitative analysis of mitral valve morphology in mitral valve prolapse with real-time 3-dimensional echocardiography: importance of annular saddle shape in the pathogenesis of mitral regurgitation

BACKGROUND

Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse.

METHODS AND RESULTS

Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR- group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR- groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%-20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r(2)=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r(2)=0.74, P<0.0001) and inversely with AHCWR (r(2)=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse.

CONCLUSION

Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.