Physiological and pathological roles of the thymus and value of thymectomy in myasthenia gravis: a narrative review.

Background and Objective: Myasthenia gravis (MG) is a well-elucidated autoimmune disorder affecting the neuromuscular junction. Given the relationship between MG and thymic pathologies, with T cell and antibody-mediated pathogenesis, surgical (i.e., thymectomy) and non-surgical approaches remain a mainstay of management of the disease. This review seeks to outline the involvement of the thymus in the development of lymphocytes leading to MG. Methods: Different databases were searched exploring the role of thymectomy in treatment and outcomes in various MG patient subpopulations, including in ocular versus generalized disease, different age groups, and antibody status. Key Content and Findings: Overall, the findings of multiple studies and reviews provide evidence to support the efficacy and long-term success of thymectomy in the management of MG; outcomes have included remission status, symptom severity, and need for adjunctive therapy. However, the heterogeneity in the MG population suggests that there are multiple factors that may confound the results of thymectomy and still need further examination. Separately, other autoimmune diseases develop following thymectomy, and further research is required to elucidate this susceptibility. Finally, our review will discuss the different surgical approaches for thymectomy, including their advantages, limitations, and perioperative complications. Conclusions: Overall, in light of the known pathogenesis and association of the thymus with MG, thymectomy remains an extremely effective approach for long-term management and improved clinical outcomes.

Trends and Outcomes of Salvage Lobectomy for Early-stage Non-Small Cell Lung Cancer.

OBJECTIVES: There is little data describing the outcomes for patients who develop local recurrences after stereotactic body radiation therapy (SBRT), a standard-of-care treatment for patients with early-stage non-small cell lung cancer. One emerging option is salvage lobectomy. We investigated trends in the use of salvage lobectomy after SBRT and described patient outcomes using a nationally representative sample. METHODS: This is a retrospective study using the National Cancer Database of patients with non-small cell lung cancer diagnosed from 2004 to 2017. We used descriptive statistics to describe patients who underwent salvage lobectomy. Kaplan-Meier analysis was used to estimate overall survival (OS). Cox proportional modeling was used to identify factors associated with OS. RESULTS: We identified 276 patients who underwent salvage lobectomy. Ninety-day mortality was 0%. The median survival time for the cohort was 50 months (95% CI, 44 to 58). Median follow-up was 65 months (Interquartile Range: 39 to 96). The factors associated with decreased OS include squamous cell histology (hazard ratio (HR)=1.72, P =0.005) and high grade (1.50, P =0.038). Increased OS was associated with lobectomy performed between 3 and 6 months after SBRT (HR=0.53, P =0.021), lobectomy performed >6 months after SBRT (HR=0.59, P =0.015), and female sex (HR=0.56, P =0.004). CONCLUSIONS: Salvage lobectomy after local failures of SBRT was associated with no perioperative mortality and favorable long-term outcomes. Our data suggest that lobectomy performed within 3 months of SBRT is associated with worse OS.

Conventional open versus hybrid aortic arch repair: a meta-analysis of propensity-matched studies.

BACKGROUND: Comparison of conventional (open) surgical versus hybrid aortic arch repair remains debatable. While the majority of previous comparative studies including meta-analyses contained primarily risk-unadjusted cohorts, those focusing on propensity-matched comparisons were limited by their small sample size. We aimed to compare outcomes of these two approaches through an up-to-date search and meta-analysis of the best evidence currently available in the literature. METHODS: The PubMed/MEDLINE, EMBASE, and Cochrane library from inception to September 2019 were searched to identify articles reporting propensity-score matching data on open versus hybrid aortic arch repair. Patients' baseline characteristics and clinical outcomes were extracted from the articles and pooled for analysis. Heterogeneity and biases were assessed among the included studies. RESULTS: Five studies, including a total of 378 patients (189 pairs), were included in the study. The two groups were similar in patients' baseline characteristics. Stroke rate favoured the open group [2.1% versus 14.3%, OR 0.18 (0.07, 0.46), P=0.0004, I2=0%]. There was no significant difference between the two groups with regard to paraplegia. The hybrid group had numerically higher short-term mortality, but lower rate of acute renal failure requiring dialysis. There was a statistically significant difference between the mid-term survivals of the open and hybrid groups, with lower pooled mortality seen for the open group at 1-year and 2-years (P=0.02). CONCLUSIONS: Open and hybrid repairs do not offer equivalent outcomes. Compared with hybrid aortic arch repair, conventional surgical aortic repair could be associated with favourable outcomes including postoperative stroke. Hybrid repair does not appear to provide better survival. Operative approaches should be carefully selected in treating aortic arch pathology.

Peritoneal Encapsulation With Incarcerated Meckel Diverticulum Contributing to Small Bowel Obstruction.

Background: Meckel diverticulum is the most common congenital gastrointestinal malformation, but it is rarely symptomatic. Peritoneal encapsulation is a rare abnormality of embryonic development and may present with obstruction, although it too is usually asymptomatic. Case Report: We report the case of an 82-year-old male who presented with symptoms and imaging findings consistent with small bowel obstruction. During laparotomy, a peritoneal encapsulation was observed containing the majority of the small bowel. A Meckel diverticulum was discovered tethered to the small bowel mesentery by a mesodiverticular band, preventing egress from the accessory peritoneal membrane and appearing to be the cause of the obstruction. Conclusion: This patient had 3 rare findings-peritoneal encapsulation, Meckel diverticulum, and a mesodiverticular band-contributing to cause an acute small bowel obstruction. The presence of all of these features in one patient is extremely rare, and we believe this is the first description of such a phenomenon.

Fortification of Preservation Solution With Nitroprusside Does Not Alter Lung Allograft Survival in Clinical Human Lung Transplantation.

Background: Nitric oxide improves gas exchange following primary lung allograft dysfunction. Nitroprusside, a potent nitric oxide donor, has reduced reperfusion injury and improved oxygenation in experimental lung transplantation. Methods: We sought to study the effect on lung allograft outcomes of fortifying the preservation solution with nitroprusside. We conducted a single-center clinical study of 46 consecutive lung recipients between 1998 and 2000: 24 patients received donor organs preserved in modified Euro-Collins solution with prostaglandin E1 (PGE1) (control group), and 22 patients received organs preserved in modified Euro-Collins with PGE1 and nitroprusside (NP group). The primary endpoint was overall survival. Results: Baseline characteristics were similar between the groups except for a significantly longer graft ischemic time in the NP group vs the control group (253.3 ± 52 vs 225.3 ± 41 minutes, respectively, P=0.04). No significant differences were found in partial pressure arterial oxygen to fraction inspired oxygen ratio at ≤48 hours, primary graft dysfunction, or bronchiolitis obliterans-free days. Overall survival at 1, 3, and 5 years was 89%, 73%, and 63% in the control group and 76%, 38%, and 23% in the NP group. Log-rank survival analysis showed that the NP group had a significantly increased risk of mortality (P=0.034) compared to the control group. Conclusion: The addition of nitroprusside to the lung transplant perfusate in this clinical trial did not improve survival; however, a large randomized trial would likely reduce confounding ischemia times and increase the power of the study.

Pulmonary Thromboendarterectomy for Pulmonary Hypertension Before Considering Transplant.

BACKGROUND: In cases of chronic thromboembolic pulmonary hypertension (CTEPH), referral for possible surgical intervention is important because surgery can be curative. Surgery necessitates cardiopulmonary bypass and deep circulatory arrest with pulmonary thrombectomy and bilateral endarterectomy (PTE). If surgery fails, lung transplant is the next best surgical option. Medical treatment is also an important adjunct. CASE REPORT: A 35-year-old female presented 3 months after a pulmonary embolus was found to be completely occluding her left pulmonary artery. She was found to have pulmonary hypertension with a pulmonary artery pressure of 81/33 mmHg, with a mean pressure of 52 mmHg. The right atrial pressure was also severely elevated at 29 mmHg, and her echocardiogram revealed severe tricuspid regurgitation and severe right ventricular dysfunction. She underwent PTE and postoperatively was followed by the heart failure team. Her 6-minute walk distance improved from 396 meters at 1 month to 670 meters at 7 months, and her pulmonary artery pressure improved significantly to 55/17 mmHg with a mean pressure of 31 mmHg. The patient's right atrial pressure also improved significantly from 29 mmHg to 13 mmHg. CONCLUSION: CTEPH is likely underrecognized, and patients with pulmonary hypertension or a history of pulmonary embolism should be screened for CTEPH. This case illustrates the surgical treatment for CTEPH and discusses alternative and adjunctive treatments. Residual pulmonary hypertension after PTE occurs in approximately 35% of patients. Overall, 4-year mortality rates after surgery appear to be approximately 15%, and mortality rates correlate with the postoperative pulmonary vascular resistance. Recognition of chronic pulmonary thromboembolic disease as the etiology of pulmonary hypertension warrants evaluation for surgery.