Effect of Smoking History on 30-Day Morbidity Following Bariatric Surgery

INTRODUCTION

Smoking and postoperative complications are well documented across surgical specialties. Preoperative smoking cessation is frequently recommended by surgeons. In this study, we assessed to what degree documented smoking history increased a patient's risk of postoperative complications.

METHODS

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database for the years 2015-2018 was used. Patients were included if they underwent primary sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (LRYGB). Patients with a documented smoking history were assigned to the "SH" cohort and patients without smoking history were assigned to the "NSH" cohort. Patients without documentation regarding smoking history, missing variables, younger than 18, with prior surgery, or lost to follow-up were excluded. 30-day morbidity and mortality data were assessed. Multiple logistic regression analysis was made based on all available patient characteristics and perioperative factors, continuous variables were analyzed using Student's t-test and categorical variables were compared using the chi-square test.

RESULTS

After evaluation of 760,076 patients on the MBSAQIP database, 650,930 patients underwent non-revisional bariatric surgery, including 466,270 SG and 184,660 LRYGB. Of the total patients included in the study, 44,606 patients were assigned to the SH cohort and 479,601 were assigned to the NSH cohort. 4628 of patients did not have documented smoking status. Within 30 days SH patients had higher rates of readmission (4.2% vs 3.7%, P < .0001), reoperation (1.3% vs 1.1%, P < .0001), unplanned intubation (.2% vs .1%, P = .0212), and unplanned ICU admission (.7% vs .0.6%, P = .0022).

CONCLUSION

SH patients undergoing bariatric surgery were at significantly increased risk of readmission and reoperation within 30 days of procedure. In addition, SH patients were more likely to have unplanned intubation and unplanned ICU admission. Given the higher rates of complications in smoking patients, this study would suggest that preoperative smoking cessation in patients prior to primary bariatric surgery might be beneficial. Further study is warranted to compare short-term cessation vs long-term cessation preoperatively, which was not assessed in our study.

A Perplexing case of isolated abducens nerve palsy in a primigravida woman: A case report

Isolated abducens nerve palsy is a rare presentation in women during pregnancy. When an abducens nerve palsy is elicited in a pregnant woman, work-up should start with labs and neuroimaging to rule out mechanical and organic causes such as tumors, preeclampsia, and multiple sclerosis. This case report highlights a 35-year-old woman, gravida 1, para 0, who was sent to the local medical center by her ophthalmologist at 37 weeks of gestation due to a left-sided headache and blurry vision. Upon admission, work-up was negative for preeclampsia. Tick-borne disease panel and lumbar puncture were unrevealing. No other mechanical or lab abnormalities were elicited. Magnetic resonance venography revealed a diminutive left transverse sinus, left sigmoid sinus, and left internal jugular vein in comparison with the right, indicating a possible congenital variant. Labor was induced to see if this would alleviate the patient's abducens nerve palsy. After induction of labor and initiation of dexamethasone, the patient's sixth cranial nerve palsy began to improve.

Incidental Findings of Appendiceal Diverticulitis Presenting as Acute Appendicitis

Diverticulosis of the appendix (DA) is a rare pathological finding that clinically imitates acute appendicitis and is most commonly found in adult males with chronic abdominal pain. It has a higher rate of perforation compared to acute appendicitis (84% vs 12%, P<0.01), and is consequently associated with a higher rate of mortality. Appendiceal diverticulitis has been found to have a significant association with incidental appendiceal neoplasms, therefore elective prophylactic appendectomy is recommended to prevent the risk of complications and to rule out the possibility of a coexisting neoplasm. Meticulous gross examination in addition to thorough histological examination of the entire appendectomy specimen by pathologists is essential in order to identify diverticula. We present two female patients with signs and symptoms consistent with acute appendicitis, they were found to have appendiceal diverticulitis on pathologic evaluation.

Cis-regulatory analysis of Onecut1 expression in fate-restricted retinal progenitor cells

Background

The vertebrate retina consists of six major classes of neuronal cells. During development, these cells are generated from a pool of multipotent retinal progenitor cells (RPCs) that express the gene Vsx2. Fate-restricted RPCs have recently been identified, with limited mitotic potential and cell fate possibilities compared to multipotent RPCs. One population of fate-restricted RPCs, marked by activity of the regulatory element ThrbCRM1, gives rise to both cone photoreceptors and horizontal cells. These cells do not express Vsx2, but co-express the transcription factors (TFs) Onecut1 and Otx2, which bind to ThrbCRM1. The components of the gene regulatory networks that control the transition from multipotent to fate-restricted gene expression are not known. This work aims to identify and evaluate cis-regulatory elements proximal to Onecut1 to identify the gene regulatory networks involved in RPC fate-restriction.

Method

We identified regulatory elements through ATAC-seq and conservation, followed by reporter assays to screen for activity based on temporal and spatial criteria. The regulatory elements of interest were subject to deletion and mutation analysis to identify functional sequences and evaluated by quantitative flow cytometry assays. Finally, we combined the enhancer::reporter assays with candidate TF overexpression to evaluate the relationship between the TFs, the enhancers, and early vertebrate retinal development. Statistical tests included ANOVA, Kruskal-Wallis, or unpaired t-tests.

Results

Two regulatory elements, ECR9 and ECR65, were identified to be active in ThrbCRM1(+) restricted RPCs. Candidate bHLH binding sites were identified as critical sequences in both elements. Overexpression of candidate bHLH TFs revealed specific enhancer-bHLH interactions. Nhlh1 overexpression expanded ECR65 activity into the Vsx2(+) RPC population, and overexpression of NeuroD1/NeuroG2/NeuroD4 had a similar effect on ECR9. Furthermore, bHLHs that were able to activate ectopic ECR9 reporter were able to induce endogenous Otx2 expression.

Conclusions

This work reports a large-scale screen to identify spatiotemporally specific regulatory elements near the Onecut1 locus. These elements were used to identify distinct populations in the developing retina. In addition, fate-restricted regulatory elements responded differentially to bHLH factors, and suggest a role for retinal bHLHs upstream of the Otx2 and Onecut1 genes during the formation of restricted RPCs from multipotent RPCs.

Quantitative analysis of the ThrbCRM1-centered gene regulatory network

Enhancer activity is determined by both the activity and occupancy of transcription factors as well as the specific sequences they bind. Experimental investigation of this dynamic requires the ability to manipulate components of the system, ideally in as close to an in vivo context as possible. Here we use electroporation of plasmid reporters to define critical parameters of a specific cis-regulatory element, ThrbCRM1, during retinal development. ThrbCRM1 is associated with cone photoreceptor genesis and activated in a subset of developing retinal cells that co-express the Otx2 and Onecut1 (OC1) transcription factors. Variation of reporter plasmid concentration was used to generate dose response curves and revealed an effect of binding site availability on the number and strength of cells with reporter activity. Critical sequence elements of the ThrbCRM1 element were defined using both mutagenesis and misexpression of the Otx2 and OC1 transcription factors in the developing retina. Additionally, these experiments suggest that the ThrbCRM1 element is co-regulated by Otx2 and OC1 even under conditions of sub-optimal binding of OC1.