P347Complications of catheter ablation for atrial fibrillation: a nation-wide study in Australia and New Zealand

Background

It is important to investigate complications of catheter ablation for atrial fibrillation (AF) - an increasingly common procedure - to inform patients and guide efforts to improve procedural quality. However, clinical trials and registries are limited by selection bias, while existing population-based studies either lack nation-wide data, or fail to report post-discharge complications. The timing and impact of these complications are also poorly understood.

Purpose

To obtain unbiased and comprehensive estimates of complications of AF ablations using national data from Australia and New Zealand. We also evaluated the impact of in-hospital complications on the length of stay and assessed the timing of post-discharge complications.

Methods

We included patients aged ≥18 years undergoing catheter ablation with a primary diagnosis of AF between 2010–2015 in all public and most private hospitals in Australia and New Zealand. The primary outcome was the occurrence of major complications in-hospital or up to 30-days after discharge. We identified major complications based on a literature review and expert clinical opinion and defined these using International Classification of Diseases – 10th revision, Australian Modification diagnoses codes and Australian Classification of Health Interventions procedure codes. We determined the impact of in-hospital complications on the length of stay, adjusting for other covariates, by using negative binomial regression, and reported results as incident rate ratio (IRR) and 95% confidence intervals (CI). Time to first post-discharge complication was evaluated using Kaplan Meier survival analysis.

Results

A total of 20,057 AF ablations were included (mean age 62.1±11.6 y, 56.7% ≤65 years old; 29.2% female; median length of stay 1 day). Of these, major complications occurred in 6.3% procedures (4.6% occurring in-hospital and a further 2.0% occurring in the 30-day post discharge). The most common complications were bleeding or haematoma formation and perforation (primarily pericardial effusion), which accounted to 60.3% and 14.3% of all complications, respectively. Rate of procedure-related deaths was 0.1%. Occurrence of an in-hospital complication more than doubled the length of stay (IRR: 2.3, 95% CI 2.2–2.4) with complications requiring cardiac surgery (IRR 4.5, 95% CI 3.2–6.4) and vascular injuries (IRR 3.9, 95% CI 3.1–4.9) having the length of stay prolonged the most (Figure 1A). In the first-week, 67.3% of post-discharge complications had occurred, and this number reached 95% within three-weeks (Figure 1B).

Conclusions

Major complications after AF ablation were common. In-hospital complications doubled the length of stay. Approximately 30% of complications occurred after discharge with the risk highest in the first seven days. Efforts to reduce complications should focus on reducing the incidence of bleeding and pericardial effusions which counted for more than 75% of all complications.

Acknowledgement/Funding

National Heart Foundation of Australia, The Hospital Research Foundation

Autism spectrum disorder in children with Type 1 diabetes

AIM

Links between autism spectrum disorder (ASD) and autoimmune diseases, including Type 1 diabetes have been proposed. This study assessed the frequency of ASD in children with Type 1 diabetes in the T1D Exchange (T1DX) registry and the impact of ASD on characteristics of children with Type 1 diabetes.

METHODS

Analysis included 10 032 participants aged < 18 years (median Type 1 diabetes duration 6.5 years, 48% female, 77% non-Hispanic White). Diagnosis of ASD was defined as autism, Asperger's or pervasive developmental disorder.

RESULTS

A diagnosis of ASD was recorded for 159 (1.58%) participants. Those with ASD were predominantly male (88% vs. 51% of those without ASD, P < 0.001) and slightly older (median 14 vs. 13 years, P = 0.022). Occurrence of diabetic ketoacidosis at Type 1 diabetes diagnosis was similar (35% vs. 41%, P = 0.161). Pump use was lower in those with ASD (51% vs. 63%, P = 0.005) but continuous glucose monitor use was similar (24% vs. 27%, P = 0.351). Median HbA_1c was slightly lower in those with ASD [68 vs. 69 mmol/mol (8.4% vs. 8.5%), P = 0.006]. This difference was more pronounced after adjusting for confounders.

CONCLUSIONS

The frequency of ASD in the T1DX registry was similar to that in the general population. These data show that despite deficits in communication, occurrence of diabetic ketoacidosis was similar in youth with and without ASD. Pump use was less frequent in those with ASD, possibly due to sensory issues, although CGM use did not differ. The lower HbA_1c may be due to a more regimented routine with ASD. Because comorbidities such as ASD complicate care of patients with Type 1 diabetes, further research is needed to support these children.

Controls on nitrogen transformation rates on restored floodplains along the Cosumnes River, California

Levee construction results in the systematic replumbing of river systems and reduces the frequency of floodplain inundation, which impacts nutrient delivery and transformations in floodplains. Floodplain restoration via levee removal affects downstream water quality by restoring soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA). Although these metabolisms are important for the nitrogen cycle, few studies have quantified the contribution of all three pathways to nitrate retention or loss in restored floodplains. The objectives of this study were to quantify the relevance of denitrification, anammox and DNRA to nitrogen retention, characterize the hydrologic conditions most favorable to each pathway, and estimate the potential for floodplain restoration to improve nitrogen cycling in the Cosumnes River watershed. To address these goals, we simulated flood conditions in soil mesocosms collected from two floodplains where levees were breached in 1997 and 2014 along the Lower Cosumnes River in the San Joaquin Basin of California. River water enriched with K¹⁵NO₃ tracer was pumped into each mesocosm at a constant rate for a period of 3 months. Samples were collected from the surface water and soil pore water for measurements of NO₃^-, NO₂^-, and NH₄⁺ concentrations, and δ¹⁵N of dissolved gases (N₂ and N₂O). To the best of our knowledge, this study reports the highest relative contribution to N₂ production due to anammox for freshwater systems (41 to 84%) to date. High anammox rates were associated with heterogeneous grain size distribution across depth and high nitrification rates. We quantify the capacity of restored floodplain soils with distinct textural and chemical characteristics to retain or release nitrogen during large and small floods in a particular water year.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Session 4: What should we do for poor responders after chemoradiotherapy: bad biology or should the fight go on?

Just over 50% of patients with advanced rectal cancer have a poor response to chemoradiotherapy with resultant poor outcomes. Professor Glimelius reviews the evidence base for defining such patients and the potential role, if any, of further treatment.

A paradigm for understanding trust and mistrust in medical research: The Community VOICES study

BACKGROUND

To promote justice in research practice and rectify health disparities, greater diversity in research participation is needed. Lack of trust in medical research is one of the most significant obstacles to research participation. Multiple variables have been identified as factors associated with research participant trust/mistrust. A conceptual model that provides meaningful insight into the interplay of factors impacting trust may promote more ethical research practice and provide an enhanced, actionable understanding of participant mistrust.

METHODS

A structured survey was developed to capture attitudes toward research conducted in emergency situations; this article focuses on items designed to assess respondents' level of trust or mistrust in medical research in general. Community-based interviews were conducted in English or Spanish with 355 New York City residents (white 42%, African American 29%, Latino 22%).

RESULTS

Generally favorable attitudes toward research were expressed by a majority (85.3%), but many respondents expressed mistrust. Factor analysis yielded four specific domains of trust/mistrust, each of which was associated with different demographic variables: general trustworthiness (older age, not disabled); perceptions of discrimination (African American, Latino, Spanish language preference); perceptions of deception (prior research experience, African American); and perceptions of exploitation (less education).

CONCLUSIONS

The four domains identified in the analysis provide a framework for understanding specific areas of research trust/mistrust among disparate study populations. This model offers a conceptual basis for the design of tailored interventions that target specific groups to promote trust of individual researchers and research institutions as well as to facilitate broader research participation.