Browsing by Author "Ma, Christopher"

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    Colonic Dieulafoy’s Lesion: A Rare Cause of Lower Gastrointestinal Hemorrhage and Review of Endoscopic Management
    (2014-10-19) Ma, Christopher; Hundal, Rajveer; Cheng, Edwin J.
    Dieulafoy’s lesions are a rare cause of gastrointestinal hemorrhage. Extragastric Dieulafoy’s lesions are even more uncommon. We report the case of a 75-year-old woman who presented with gastrointestinal bleeding from a transverse colonic Dieulafoy’s lesion. She presented with two episodes of melena followed by one episode of fresh blood per rectum. In addition, there was associated presyncope and anemia (hemoglobin 69 g/L) in the setting of supratherapeutic warfarin anticoagulation (INR 6.2) for nonvalvular atrial fibrillation. Esophagogastroduodenoscopy was negative for an upper GI source of bleeding but on colonoscopy an actively oozing Dieulafoy’s lesion was identified in the transverse colon. Bipolar cautery and hemostatic endoclips were applied to achieve hemostasis. Clinicians should consider this rare entity as a potential cause of potentially life-threatening lower gastrointestinal bleeding and we review the endoscopic modalities effective for managing colonic Dieulafoy’s lesions.
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    Epidemiology and outcomes of choledocholithiasis and cholangitis in the United States: trends and urban-rural variations
    (2023-07-27) Li, Suqing; Guizzetti, Leonardo; Ma, Christopher; Shaheen, Abdel A.; Dixon, Elijah; Ball, Chad; Wani, Sachin; Forbes, Nauzer
    Abstract Background Gallstone disease poses a significant health burden in the United States. Choledocholithiasis and cholangitis are common complications of gallstone disease for which data on current epidemiological trends are lacking. We aimed to evaluate temporal changes in hospitalization, management, and outcomes for patients with choledocholithiasis and cholangitis. Methods The National Inpatient Sample was used to identify discharges for choledocholithiasis and cholangitis between 2005 and 2014. Temporal trends were evaluated via annual percent changes (APCs). Joinpoint regression was used to assess inflection points. Multivariable regression models were used to evaluate associations of interest. Results From 189,362 unweighted discharges for choledocholithiasis and/or cholangitis, there was an increase in discharges for choledocholithiasis (APC 2.3%, 95% confidence intervals, CI, 1.9–2.7%) and cholangitis (APC 1.5%, 95% CI 0.7–2.2%). Procedural interventions were more likely at urban hospitals for choledocholithiasis (adjusted odds ratio, aOR, 2.94, 95% CI 2.72 to 3.17) and cholangitis (aOR 2.97, 95% CI 2.50 to 3.54). In-hospital mortality significantly decreased annually for choledocholithiasis (aOR 0.90, 95% CI 0.88 to 0.93) and cholangitis (aOR 0.93, 95% CI 0.89 to 0.97). In-hospital mortality between rural and urban centers was comparable for choledocholithiasis (aOR 1.16, 95% CI 0.89 to 1.52) and cholangitis (aOR 1.12, 95% CI 0.72 to 1.72). Conclusions Hospitalizations for choledocholithiasis and cholangitis have increased between 2005 and 2014, reflecting a growing burden of gallstone disease. Hospital mortality between urban and rural centers is similar, however urban centers have a higher rate of procedural interventions suggesting limitations to accessing procedural interventions at rural centers.
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    Geographic Differences in the Risk of Surgery in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis
    (2021-11-15) Hansen, Tawnya; Kaplan, Gilaad; Ma, Christopher; Novak, Kerri
    Crohn’s disease (CD) and ulcerative colitis (UC), collectively known as the inflammatory bowel diseases (IBD), are chronic immune mediated conditions. The pathophysiology of these disease is not well understood but genetic predisposition, dietary and microbiome-related factors, and environment exposures have been previously implicated. These diseases have traditionally been thought of as diseases of Caucasians living in the Western world: North America, Europe, and Oceania. However, the incidence of these diseases has been increasing in newly industrialized countries in Asia, Africa, and Latin America. In the Western world, a large proportion of healthcare spending related to IBD management has been on biologic agents.These biologic agents are very costly and are thought to decrease the risk of surgery. The risks of surgery among patients with IBD in the Western world is well described. However, the risks of IBD surgery in Asian countries has not been well assessed. Therefore, the aim of this thesis is to determine the risk of IBD surgery among persons in Asia compared to persons living in Western countries.A systematic review was conducted to identify all population-based studies reportingrisk of IBD surgery for Crohn’s disease or ulcerative colitis among inception cohorts diagnosed in the year 1999 or later. A meta-analysis was performed to pool the risk of surgery for Western and Asian countries. Choropleth maps were generated to highlight regional differences in surgery risk (https://arcg.is/5r48K).
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    Postoperative complications following colectomy for ulcerative colitis: A validation study
    (BioMed Central, 2012) Kaplan, Gilaad G.; Ma, Christopher; Crespin, Marcelo; Proulx, Marie-Claude; DeSilva, Shanika; Hubbard, James; Prusinkiewicz, Martin; Nguyen, Geoffrey C; Panaccione, Remo; Ghosh, Subrata; Myers, Robert P; Quan, Hude
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    Serological Responses and Breakthrough Infection Frequencies after SARS-CoV-2 Vaccination in Inflammatory Bowel Disease
    (2023-06) Sharifi, Nastaran; Kaplan, Gilaad; Seow, Cynthia; Ma, Christopher
    This study evaluates serological responses to SARS-CoV-2 vaccination in individuals with inflammatory bowel disease (IBD). Serological responses to two, three, and four doses of a SARS-CoV-2 vaccine were assessed. We also aimed to determine the frequency of COVID-19 breakthrough infections (BTIs) in individuals with IBD during the Omicron wave and assess the association between antibodies and time to BTIs post-3rd dose vaccination. Five hundred fifty-nine adults with IBD who received at least one dose of a SARS-CoV-2 vaccine were enrolled. Serological responses were evaluated using the Abbott IgG II Quant assay and geometric mean titers (GMT) were calculated for each vaccine dose and serology time point. BTIs were assessed for nine months (Dec 1, 2021, to Sep 1, 2022) during the Omicron wave and confirmed through PCR, self-reported rapid antigen test, and/or positive nucleocapsid antibody levels. Cox proportional hazard models were evaluated to determine the effect of antibody concentration on the time from the 3rd dose vaccination to BTI after adjusting for demographic-, vaccine-, and treatment-related factors. In our cohort (n=559), 17.2 % were above 65 years of age, 53.1% were female, and 71.6% had Crohn’s diseaseSerological responses showed an increase in GMTs 1¬–8 weeks after each consecutive vaccine dose, wth the highest GMTs observed 1–8 weeks after the 2nd (4053 AU/mL), 3rd (12116 AU/mL), and 4th (14337 AU/mL) doses. GMTs decreased in the 8–16-week period after each dose, but levels remained stable beyond 16 weeks. Despite stability in antibody levels overtime, the cumulative incidence of Omicron-era BTI was 26.6% (95% CI: 22.4, 30.9%). Antibody concentration (anti-S) and neutralizing antibodies (NT50) were not associated with time from 3rd dose to breakthrough infection after adjusting for clinically relevant covariates (HR=0.70; 95% CI: 0.39, 1.24; p=0.22) and (HR=0.99; 95% CI: 0.99, 1.00; p=0.20). Overall, serological responses to SARS-CoV-2 vaccination increased after consecutive doses in those with IBD but decreased 8–16 weeks following each dose with titers stabilizing beyond 16 weeks. Cumulative incidence of BTI during the Omicron-era was high, and serum IgG and neutralizing antibodies were not predictive of BTI following 3rd dose vaccination.
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    Serological Responses to SARS-CoV-2 Vaccination in Inflammatory Bowel Disease
    (2022-05-18) Quan, Joshua; Kaplan, Gilaad G; Ma, Christopher; Panaccione, Remo
    Inflammatory bowel disease (IBD) refers to a group of disorders characterized by chronic inflammation and ulceration of the gastrointestinal tract. In context of the ongoing COVID-19 pandemic, individuals with IBD have an increased risk of hospitalization from COVID-19 and certain IBD therapies are related to increased risks of infection and severe disease. Although SARS-CoV-2 vaccines can mitigate infection risk, individuals with IBD may have reduced serological responses based on their condition and use of immunosuppressive medications. Therefore, we investigated serological responses following 1st, 2nd, and 3rd doses of SARS-CoV-2 vaccination.A prospective cohort study of persons with IBD in the Calgary area (n = 496) assessed serological response at the following timepoints: 1–8 weeks after 1st dose vaccination, 1–8 weeks after 2nd dose, eight or more weeks after 2nd dose, and at least one week after 3rd dose. Seroconversion and geometric mean titer (GMT) with 95% confidence intervals were assessed for antibodies to the SARS-CoV-2 spike protein using the Abbott Architect SARS-CoV-2 IgG II Quant Assay. Multivariable linear regression models assessed the impact of age, sex, IBD type, medication class, vaccine schedule, prior SARS-CoV-2 infection, and time following vaccination on antibody concentration following each dose of vaccine. Seroconversion and GMT increased consecutively with each dose of vaccine, with the highest values corresponding to after 3rd dose vaccination. Older age and several medication classes were related to decreased antibody titres post-2nd dose, whereas use of prednisone was the only factor associated with diminished antibody response after 3rd dose vaccination. Antibody levels steadily decline following the 2nd and 3rd doses of SARS-CoV-2 vaccination. In this thesis, we aimed to evaluate serological responses to SARS-CoV-2 vaccination and were able to determine a robust antibody response to a three-dose regimen across all classes of IBD therapies except for prednisone. Decaying antibody levels following 3rd dose vaccination should be monitored in future studies and other measures of vaccine-induced protection against SARS-CoV-2 such as neutralizing antibodies, T-cell responses, and vaccine effectiveness should be evaluated. In conclusion, three-dose SARS-CoV-2 vaccine regimens induce substantial immunogenicity in those with IBD and should be emphasized for serological protection.