Analgesic effects of a 5-HT3 receptor antagonist in an animal model of complex regional pain syndrome

OBJECTIVE

Complex regional pain syndrome (CRPS) is caused by injuries from fracture after trauma and orthopaedic surgical procedures in the hind limbs. The symptoms of CRPS include warmth, pain, allodynia, and hyperalgesia. It is known that 5-hydroxytryptamine 3 (5-HT3) receptors contribute to hyperalgesia, but their role has not yet been fully elucidated. This study investigated the mechanism of pain relief when a 5-HT3 receptor antagonist was administered in a CRPS animal model.

MATERIALS AND METHODS

To establish a CRPS animal model, 10-week-old Sprague-Dawley rats were used in the experiment. On the fourth week post tibial fracture surgery, we performed the von Frey test to measure mechanical allodynia. After performing behavioural tests, we collected blood and tissue samples after sacrificing the animals. Enzyme-linked immunosorbent assay and western blot were also performed.

RESULTS

The experimental tibia fracture model-induced CRPS animals elicited increased 5-HT3 receptor expression, and the 5-HT transporter was decreased in the brain stem after 4 weeks of surgical intervention. Additionally, in CRPS-induced animals, both the concentration of substance P and the level of interleukin 6 were increased peripherally and centrally. Treatment with the 5-HT3 receptor antagonist, ramosetron, exerted an analgesic effect in the paw withdrawal test and was dependent on the attenuation of the 5-HT3 receptor population with inflammatory pain mediators.

CONCLUSIONS

These data suggest that treatment with the 5-HT3 receptor antagonist, ramosetron, in experimental CRPS animal models alleviated pain-related behaviours and may be a new therapeutic option or potential therapeutic agent for patients with CRPS.

The surge in fatal diabetic ketoacidosis in the years of the COVID-19 pandemic: a forensic autopsy study

Introduction/Objective

Although many deaths resulting from diabetic ketoacidosis (DKA) fall outside the legal jurisdiction of the medical examiner, a forensic pathologist may identify this cause of death through ancillary testing multiple times per year. We recognized a sharp increase in deaths due to DKA at a busy metropolitan medical examiner’s office in 2020 and 2021, coinciding with the COVID-19 pandemic. We hypothesize that in the majority of these cases, fatal DKA was the presenting symptom of previously undiagnosed diabetes mellitus (DM).

Methods/Case Report

We performed a retrospective autopsy review of all cases with a cause of death listed as “diabetic ketoacidosis” from January 1, 2018 through June 18, 2021. We compared the number of DKA deaths to all reported deaths from the same time period.

Results (if a Case Study enter NA)

We identified a total 34 cases of fatal DKA. In 2018, 5 cases of DKA were identified and all decedents had a known diagnosis of DM; the average age at death was 50.6 years (range: 40- 60 years) and 2 decedents were male (40%). In 2019, 5 cases of DKA were identified and 4 decedents had a known diagnosis of DM (80%); the average age at death was 51.4 years (range: 37- 61 years), and all decedents were male (100%). In 2021, 18 cases of DKA were identified and 9 decedents had a previous diagnosis of DM (50%); the average age at death was 43.5 years (range: 22- 64 years), 13 decedents were male (72%), and 1 decedent was COVID-19 positive (5.5%). In the first 6 months of 2021, 6 cases of DKA were identified and none of these decedents had a previous diagnosis of DM (0%); the average at death was 51.8 years (range: 35- 73 years), 4 decedents were male (66%), and 1 decedent was COVID-19 positive (16.6%). Reported deaths per year to our office are as follows: 2018 = 2585 deaths, 2019 = 2658 deaths, 2020 = 3091 deaths, and 2021 to date = 1482 deaths.

Conclusion

Coinciding with the COVID-19 pandemic, our office experienced a 16.2% increase in all reported deaths from 2019 to 2020, and a 260% increase in fatal DKA. In 2018 and 2019, 9 of the 10 decedents who died from DKA had a known diagnosis of DM (90%). However, in 2020 and the first half of 2021, DKA was the presenting symptom of previously undiagnosed DM in 15 of 24 cases of fatal DKA (62.5%). Further investigation must be done to examine the factors driving the recent surge in fatal DKA.

Patterns of left ventricular recovery in patients with heart failure with mid-range ejection fraction

Background

Heart failure with mid-range ejection fraction (HFmEF) represents a new classification of heart failure with intermediate clinical characteristics to those with HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). A proportion of HFmEF is attributed to atrio-ventricular dyssynchrony from atrial fibrillation (AF) as opposed to a primary cardiomyopathy with intrinsic cardiac myocyte dysfunction.

Purpose

We aim to compare the rate of left ventricular ejection fraction (LVEF) recovery in those with AF-mediated cardiomyopathy compared to those with primary myocyte dysfunction.

Methods

Consecutive patients with stable non-ischaemic cardiomyopathy with LVEF 40–49% on transthoracic echocardiography (TTE) were recruited from our institution's heart failure clinic and followed for 18 months. Patients with ischaemic, valvular or congenital heart disease, incomplete follow-up or poor quality TTE images were excluded. Eligible patients were separated into two groups: AF-mediated (n=44); and primary myocyte dysfunction (n=116).

Results

A total of 160 patients (62.1±16.4 years, 62% men) were included. There was no significant difference in age (p=0.06) and gender (p=0.59). Comorbid AF was higher in those with AF-mediated HFmEF (100 vs 28.4%; p<0.01), otherwise no significant differences in clinical history was found between groups. AF-mediated HFmEF had lower rates of cardiac-specific beta-blocker use (15.9 vs 47.4%; p<0.01). Baseline TTE showed similar LVEF and LV global longitudinal strain. On log-rank analysis there was no significant difference in all-cause death (p=0.75), or HF-related hospitalisation (p=0.14), however, higher rates of LVEF recovery were observed in the AF-mediated HFmEF group (p<0.01). See figure 1.

Conclusion

There were higher rates of LVEF recovery in those with AF-mediated HFmEF compared to those with a primary myocardial disorder despite lower rates of cardiac-specific beta-blocker use. This did not translate to improvements in intermediate-term survival or HF related hospitalisation. These findings provide insight into the natural history of the disorder and its clinical phenotype.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Rate of LVEF Recovery

The role of premorbid transthoracic echocardiogram in identifying adverse clinical outcomes in patients admitted with COVID-19

Background/Introduction

The novel coronavirus disease (COVID-19) inpatient mortality rate is approximately 20% in the United States. Reports have described a wide pattern of abnormalities in echocardiograms performed in patients admitted with COVID-19. The role of premorbid transthoracic echocardiogram (TTE) in the prediction of COVID-19 severity and mortality is yet to be fully assessed.

Purpose

To assess whether a pre-COVID TTE can identify patients at high risk of adverse outcomes who are admitted with COVID-19.

Methods

All patients who underwent a TTE from one year to one month prior to an index inpatient admission for COVID-19 were retrospectively enrolled across five clinical sites. Demographic information, medical history, and laboratory data were included for analysis. Echocardiograms were analyzed by an observer blinded to clinical data. Linear and logistic regressions were performed to detect the association of variables with death, invasive mechanical ventilation, initiation of dialysis, and a composite of these endpoints during the COVID-19 admission. Outcomes were then adjusted for a risk score using inverse propensity weighting incorporating age, sex, diabetes, hypertension, obstructive sleep apnea, history of atherosclerotic cardiovascular disease, atrial fibrillation, diuretic use, and angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use.

Results

There were 104 patients (68±15 years old, 49% male, BMI 31.4±9.1kg/m2) who met inclusion criteria (baseline characteristics in Table 1). Mean time from TTE to positive SARS-CoV-2 PCR test was 139±91 days. Twenty-nine (28%) participants died during the index COVID-19 admission. There was no association of pre-COVID echocardiographic measures of systolic ventricular function with any endpoint. Diastolic function, as assessed by LV e', was associated with mortality (Table 2). There were 25 patients (24%) with a normal lateral e' (≥10cm/s); none died. There were 35 (34%) patients with LV e' lateral velocity <8 cm/s, of whom 15 (43%) died. LV e' lateral velocity <8 cm/s was associated with an unadjusted odds ratio of 7.69 (95% confidence interval [CI] 2.26–26.19) for death and 3.25 (95% CI 1.11–9.54) for the composite outcome. The odds ratio for death was 4.76 (95% CI 1.10–20.61) and 3.78 (95% CI 0.98–14.6) for the composite outcome after adjustment for clinical risk factors (Table 2).

Conclusion

In patients with an echocardiogram prior to COVID-19, impaired diastolic function as represented by an abnormal LV e' lateral velocity was associated with both inpatient COVID-19 mortality and a composite outcome of death, mechanical ventilation, and initiation of dialysis, even after adjustment for multiple co-morbidities and medication use. Knowledge of the pre-COVID TTE results may help clinicians identify patients at higher risk of adverse outcomes during an admission for COVID-19.

Funding Acknowledgement

Type of funding sources: None.

Remdesivir induces persistent mitochondrial and structural damage in human induced pluripotent stem cell derived cardiomyocytes

AIMS

Remdesivir is a prodrug of an adenosine triphosphate analogue and is currently the only drug formally approved for the treatment of hospitalised COVID-19 patients. Nucleoside/nucleotide analogues have been shown to induce mitochondrial damage and cardiotoxicity, and this may be exacerbated by hypoxia, which frequently occurs in severe COVID-19 patients. Although there have been few reports of adverse cardiovascular events associated with remdesivir, clinical data are limited. Here, we investigated whether remdesivir induced cardiotoxicity using an in vitro human cardiac model.

METHODS AND RESULTS

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were exposed to remdesivir under normoxic and hypoxic conditions to simulate mild and severe COVID-19 respectively. Remdesivir induced mitochondrial fragmentation, reduced redox potential and suppressed mitochondrial respiration at levels below the estimated plasma concentration under both normoxic and hypoxic conditions. Non-mitochondrial damage such as electrophysiological alterations and sarcomere disarray were also observed. Importantly, some of these changes persisted after the cessation of treatment, culminating in increased cell death. Mechanistically, we found that inhibition of DRP1, a regulator of mitochondrial fission, ameliorated the cardiotoxic effects of remdesivir, showing that remdesivir-induced cardiotoxicity was preventable and excessive mitochondrial fission might contribute to this phenotype.

CONCLUSIONS

Using an in vitro model, we demonstrated that remdesivir can induce cardiotoxicity in hiPSC-CMs at clinically relevant concentrations. These results reveal previously unknown potential side-effects of remdesivir and highlight the importance of further investigations with in vivo animal models and active clinical monitoring to prevent lasting cardiac damage to patients.

TRANSLATIONAL PERSPECTIVE

Adult cardiomyocytes have limited ability to regenerate, thus treatment-induced cardiotoxicity can potentially cause irreparable harm. Remdesivir is currently the only FDA approved treatment for COVID-19 but clinical safety data are limited. Using human pluripotent stem cell-derived cardiomyocytes, we revealed that remdesivir induced persistent mitochondrial and structural abnormalities at clinically relevant concentrations. We advise confirmatory experiments in in vivo animal models, investigations of cardioprotective strategies, and closer patient monitoring such that treatment-induced cardiotoxicity does not contribute to the long term sequelae of COVID-19 patients.

COVID-19 DIAGNOSIS BY POINT OF CARE LUNG ULTRASOUND: A NOVEL DEEP LEARNING ARTIFICIAL INTELLIGENCE METHOD

BACKGROUND

METHODS AND RESULTS

CONCLUSION

Community interventions for improving adult mental health: mapping local policy and practice in England

BACKGROUND

Public mental health (PMH) aims to improve wellbeing and prevent poor mental health at the population level. It is a global challenge and a UK priority area for action. Communities play an important role in the provision of PMH interventions. However, the evidence base concerning community-based PMH interventions is limited, meaning it is challenging to compare service provision to need. Without this, the efficient and equitable provision of services is hindered. Here, we sought to map the current range of community-based interventions for improving mental health and wellbeing currently provided in England to inform priority areas for policy and service intervention.

METHOD

We adopted an established mapping exercise methodology, comparing service provision with demographic and deprivation statistics. Five local authority areas of England were selected based on differing demographics, mental health needs and wider challenging circumstances (i.e. high deprivation). Community-based interventions were identified through: 1) desk-based research 2) established professional networks 3) chain-referral sampling of individuals involved in local mental health promotion and prevention and 4) peer researchers' insight. We included all community-based, non-clinical interventions aimed at adult residents operating between July 2019 and May 2020.

RESULTS

407 interventions were identified across the five areas addressing 16 risk/protective factors for PMH. Interventions for social isolation and loneliness were most prevalent, most commonly through social activities and/or befriending services. The most common subpopulations targeted were older adults and people from minority ethnic backgrounds. Interventions focusing on broader structural and environmental determinants were uncommon. There was some evidence of service provision being tailored to local need, though this was inconsistent, meaning some at-risk groups such as men or LGBTQ+ people from minority ethnic backgrounds were missed. Interventions were not consistently evaluated.

CONCLUSIONS

There was evidence of partial responsiveness to national and local prioritising. Provision was geared mainly towards addressing social and individual determinants of PMH, suggesting more integration is needed to engage wider service providers and policy-makers in PMH strategy and delivery at the community level. The lack of comprehensive evaluation of services to improve PMH needs to be urgently addressed to determine the extent of their effectiveness in communities they serve.

Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. III: Relation with solid passage rate and pH on prokaryotic fatty acid profile and community in continuous culture

Our objectives were to evaluate potential interactions in culture conditions that influence how exogenously dosed branched-chain VFA (BCVFA) would be recovered as elongated fatty acids (FA) or would affect bacterial populations. A 2 × 2 × 2 factorial arrangement of treatments evaluated 3 factors: (1) without versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate; each dose was partially substituted with ¹³C-enriched tracers before and during the collection period); (2) high versus low pH (ranging diurnally from 6.3 to 6.8 vs. 5.7 to 6.2); and (3) low versus high particulate-phase passage rate (k_p; 2.5 vs. 5.0%/h) in continuous cultures administered a 50:50 forage:concentrate diet twice daily. Samples of effluent were collected and composited before harvesting bacteria from which FA and DNA were extracted. Profiles and enrichments of FA in bacteria were evaluated by gas chromatography and isotope-ratio mass spectrometry. The ¹³C enrichment in bacterial FA was calculated as percentage recovery of dosed ¹³C-labeled BCVFA. Dosing BCVFA increased the even-chain iso-FA, preventing the reduced concentration at higher k_p and potentially as a physiological response to decreased pH. However, decreasing pH decreased recovery of ¹³C in these even-chain FA, suggesting greater reliance on isobutyrate produced from degradation of dietary valine. The iso-FA were decreased, whereas anteiso-FA and 16:0 increased with decreasing pH. Thus, 2-methylbutyrate still appeared to be important as a precursor for anteiso-FA to counter the increased rigidity of bacterial membranes that had more saturated straight-chain FA when pH decreased. Provision of BCVFA stimulated the relative sequence abundance of Fibrobacter and Treponema, both of which require isobutyrate and 2-methylbutyrate. Numerous bacterial community members were shifted by low pH, including increased Prevotella and genera within the phylum Proteobacteria, at the expense of members within phylum Firmicutes. Because of relatively few interactions with pH and k_p, supplementation of BCVFA can stimulate neutral detergent fiber degradability via key fibrolytic bacteria across a range of conditions. Decreasing pH shifted bacterial populations and their FA composition, suggesting that further research is needed to distinguish pH from dietary changes.

Common deletion variants causing protocadherin-α deficiency contribute to the complex genetics of BAV and left-sided congenital heart disease

Bicuspid aortic valve (BAV) with ~1%-2% prevalence is the most common congenital heart defect (CHD). It frequently results in valve disease and aorta dilation and is a major cause of adult cardiac surgery. BAV is genetically linked to rare left-heart obstructions (left ventricular outflow tract obstructions [LVOTOs]), including hypoplastic left heart syndrome (HLHS) and coarctation of the aorta (CoA). Mouse and human studies indicate LVOTO is genetically heterogeneous with a complex genetic etiology. Homozygous mutation in the Pcdha protocadherin gene cluster in mice can cause BAV, and also HLHS and other LVOTO phenotypes when accompanied by a second mutation. Here we show two common deletion copy number variants (delCNVs) within the PCDHA gene cluster are associated with LVOTO. Analysis of 1,218 white individuals with LVOTO versus 463 disease-free local control individuals yielded odds ratios (ORs) at 1.47 (95% confidence interval [CI], 1.13-1.92; p = 4.2 × 10-3) for LVOTO, 1.47 (95% CI, 1.10-1.97; p = 0.01) for BAV, 6.13 (95% CI, 2.75-13.7; p = 9.7 × 10-6) for CoA, and 1.49 (95% CI, 1.07-2.08; p = 0.019) for HLHS. Increased OR was observed for all LVOTO phenotypes in homozygous or compound heterozygous PCDHA delCNV genotype comparison versus wild type. Analysis of an independent white cohort (381 affected individuals, 1,352 control individuals) replicated the PCDHA delCNV association with LVOTO. Generalizability of these findings is suggested by similar observations in Black and Chinese individuals with LVOTO. Analysis of Pcdha mutant mice showed reduced PCDHA expression at regions of cell-cell contact in aortic smooth muscle and cushion mesenchyme, suggesting potential mechanisms for BAV pathogenesis and aortopathy. Together, these findings indicate common variants causing PCDHA deficiency play a significant role in the genetic etiology of common and rare LVOTO-CHD.

Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. II: Relation with solid passage rate and pH on neutral detergent fiber degradation and microbial function in continuous culture

To support improving genetic potential for increased milk production, intake of digestible carbohydrate must also increase to provide digestible energy and microbial protein synthesis. We hypothesized that the provision of exogenous branched-chain volatile fatty acids (BCVFA) would improve both neutral detergent fiber (NDF) degradability and efficiency of microbial protein synthesis. However, BCVFA should be more beneficial with increasing efficiency of bacterial protein synthesis associated with increasing passage rate (k_p). We also hypothesized that decreasing pH would increase the need for isobutyrate over 2-methylbutyrate. To study these effects independent from other sources of variation in vivo, we evaluated continuous cultures without (control) versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate), low versus high k_p of the particulate phase (2.5 vs. 5.0%/h), and high versus low pH (ranging from 6.3 to 6.8 diurnally vs. 5.7 to 6.2) in a 2 × 2 × 2 factorial arrangement of treatments. Diets were 50% forage pellets and 50% grain pellets administered twice daily. Without an interaction, NDF degradability tended to increase from 29.7 to 35.0% for main effects of control compared with BCVFA treatments. Provision of BCVFA increased methanogenesis, presumably resulting from improved NDF degradability. Decreasing pH decreased methane production. Total volatile fatty acid (VFA) and acetate production were decreased with increasing k_p, even though true organic matter degradability and bacterial nitrogen flow were not affected by treatments. Decreasing pH decreased acetate but increased propionate and valerate production, probably resulting from a shift in bacterial taxa and associated VFA stoichiometry. Decreasing pH decreased isobutyrate and isovalerate production while increasing 2-methylbutyrate production on a net basis (subtracting doses). Supplementing BCVFA improved NDF degradability in continuous cultures administered moderate (15.4%) crude protein diets (excluding urea in buffer) without major interactions with culture pH and k_p.

POS0771 VALIDATION OF THE 2019 EUROPEAN LEAGUE AGAINST RHEUMATISM/AMERICAN COLLEGE OF RHEUMATOLOGY (EULAR/ACR) CLASSIFICATION CRITERIA FOR SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) IN HONG KONG CHINESE

Objectives:

To validate the 2019 EULAR/ACR classification criteria for SLE in Hong Kong Chinese patients and compare its performance with the 2012 Systemic Lupus International Collaborating Clinics (SLICC) and 1997 American college of rheumatology (ACR) criteria.

Methods:

We retrospectively reviewed the medical records of consecutive patients who attended the Rheumatology clinics in Tuen Mun and Pok Oi hospitals between May and September 2019. Patients with anti-nuclear antibody (ANA) ≥1:80 were included and patients with ANA <1:80 or no ANA results were excluded. Patients were evaluated and cross-checked for the fulfilment of the 1997 ACR, 2012 SLICC and 2019 EULAR/ACR criteria by two investigators (YKC,CL). Medical records were then reviewed by an expert panel consisting of 3 senior rheumatologists, who were blinded for the results of the criteria evaluation, for a diagnosis of SLE based on the clinical judgement and therapeutic decisions. Teleconferences were arranged by the panel to discuss the discrepancies of the final diagnosis and agreement was made by voting. The three SLE criteria were evaluated against the clinical diagnosis of SLE as judged by the expert panel on the sensitivity and specificity, which was calculated by 2x2 contingency tables (“condition positive” = clinical diagnosis of SLE; “test positive” = criteria positive for SLE) with standard formulas (sensitivity = true positive/[true positive + false negative]; specificity = true negative / [true negative + false positive]). Receiver operating characteristic (ROC) curve was used to study the optimal cut-off points from the EULAR/ACR criteria for the highest summation of specificity and sensitivity.

Results:

3967 patients were screened; 1542 patients who were positive for ANA (≥1:80) were included (88.3% women). The mean age of these patients at first rheumatology clinic attendance was 45.6±15.0 years and the duration of follow-up was 7.5±7.0 years. A total of 567 patients were judged to have SLE by the expert panel (discrepancy of clinical diagnosis in 135 patients resolved with voting). The sensitivity and specificity of the three SLE classification criteria in our patients are listed in Table 1. ROC analysis showed that the best cut-off for a clinical diagnosis of SLE using the EULAR/ACR criteria was 10 points (area under the curve [AUC] 0.977; sensitivity 89.2% and specificity 89.6%). Similar figures were obtained for subgroups of patients stratified by gender and different age ranges.

Conclusion:

In our cohort of Hong Kong Chinese patients, the 2019 EULAR/ACR criteria is more sensitive but less specific when compared with 1997 ACR criteria for classifying SLE. On the other hand, the EULAR/ACR criteria is less sensitive but more specific than the 2012 SLICC criteria. The specificity of the EULAR/ACR criteria for SLE is higher in male than female patients. In our patients older than 50 years, the EULAR/ACR criteria is less sensitive but more specific for a classification of SLE. Overall, the performance of the EULAR/ACR criteria for a diagnosis of SLE in our study is similar to that reported in recent Asian studies although the sensitivity is lower, which may be related to the inclusion of ANA+ patients only.

References:

Classification criteriaSensitivitySpecificity1997 ACR85.9%94.4%2012 SLICC97.5%86.4%2019 EULAR/ACR with 10 points as cut-off89.2%89.6%2019 EULAR/ACR with 9 points as cut-off93.6%68.7%2019 EULAR/ACR with 11 points as cut-off86.9%92.4%2019 EULAR/ACR with 10 points as cut-off (men)88.9%94.5%2019 EULAR/ACR with 10 points as cut-off (women)89.2%88.8%2019 EULAR/ACR with 10 points as cut-off (age >50 years)78.7%94.1%2019 EULAR/ACR with 10 points as cut-off (age ≤50 years)91.7%84.1%

Disclosure of Interests:

None declared

POS0773 CLINICAL PRESENTATION AND OUTCOMES OF THE ANTIPHOSPHOLIPID SYNDROME (APS) IN SOUTHERN CHINESE PATIENTS: THE HONG KONG APS REGISTRY

Objectives:

To report the clinical presentation and outcomes of the APS in Hong Kong Chinese patients.

Methods:

The HKAPS registry was established in early 2020 by the Hong Kong Society of Rheumatology to study the outcomes of Chinese patients with APS treated in public hospitals in Hong Kong. Patients aged ≥18 years were identified by the Hospital Authority Clinical Data retrieval system using the ICD-10 diagnostic code of APS. The medical history and APS diagnosis was verified by sub-investigators in different hospitals using the 2006 modified consensus criteria for the APS. Eligible patients were classified into definite APS or probable APS, which was further categorized into primary (without underlying rheumatic diseases) and secondary types. The presentation, treatment and outcomes of these patients were summarized.

Results:

232 APS patients (76.3% women) were identified. All were ethnic Chinese. A total of 160 patients fulfilled the 2006 criteria for APS (definite APS) while 72 patients had probable APS (anti-phospholipid [aPL] antibodies positive once or with non-criteria manifestations). In those with definite APS, the mean age at diagnosis was 44.9±15.8 years and the female to male ratio was 3.1:1. APS was primary in 82 patients while 78 patients had concomitant rheumatic diseases (SLE in 95% of patients). 130(81%) patients had thromboembolic manifestations, 20(13%) had obstetric morbidities and 10(6%) had both. In patients with secondary APS, 23% thrombotic or obstetric manifestations occurred before diagnosis of the rheumatic diseases (ie. evolved from primary APS). Lupus anticoagulant was present in 81(51%) patients, moderate/high titers of anti-cardiolipin were present in 90(56%) patients and anti-β2glycoprotein-1 was present in 6(4%) patients. Sixteen (10%) patients were double positive while 1 patient was triple positive for these aPL antibodies. Among the thromboembolic manifestations, arterial thrombosis (n=84) (ischemic stroke 77%, myocardial infarction 4.8%, peripheral vascular disease with limb/digital gangrene 2.4%, retinal artery 2.4%, splenic artery 1.2%, bowel infarct 1.2%) was more common than venous thrombosis (n=73) (calf vein thrombosis ± pulmonary embolism 86%, cerebral veins 2.7%, inferior vena cava/iliac veins 6.8%, retinal vein 2.7%, splenic vein 1.4%). The following treatment regimens were used in our APS patients: warfarin (71%), aspirin plus subcutaneous heparin (4%), aspirin + warfarin (3.1%), aspirin alone (17%) and the direct oral anticoagulant (DOAC) (5%). Bleeding complications developed in 35(22%) patients. Over a mean follow-up of 9.9±7.0years, recurrence of thromboembolic or obstetric manifestations recurred in 39(24%) and 6(4%) patients, respectively. A total of 29(18%) patients succumbed (median time to death: 6.4 years) and the causes of death were: pneumonia (24%), septicemia (17%), intracranial hemorrhage (14%), myocardial infarction (10%), ischemic stroke (3%), bowel infarct (3%), pulmonary hypertension (6.9%) and sudden death with unknown causes (14%).

Conclusion:

APS in southern Chinese is relatively uncommon and most cases were associated with SLE. In contrast with the Caucasians, venous thrombosis related to APS is less frequent than arterial thrombosis in Chinese patients. With long-term anticoagulation treatment, the outcome is satisfactory with relatively low rates of recurrence and mortality. Expansion of the sample size to study factors associated with recurrence and mortality by involving more hospitals is in progress.

Disclosure of Interests:

None declared

Laryngectomy with a Tritube® and flow-controlled ventilation

We describe the novel use of the TriTube^® and Evone^® ventilator (Ventinova, Eindhoven, Netherlands) to facilitate curative resection of a transglottic squamous cell carcinoma. A 43-year-old man presented with acute laryngeal and subglottic airway obstruction secondary to a stage 4 transglottic squamous cell carcinoma. The patient underwent magnetic resonance imaging followed by a diagnostic panendoscopy. It was decided that tumour resection was appropriate and a management plan was established by a multi disciplinary team. A total laryngectomy was performed. It was determined that failure of translaryngeal tracheal intubation could be rescued with emergency surgical front-of-neck airway. General anaesthesia was induced using a total intravenous anaesthesia technique, oxygenation was achieved with high-flow nasal oxygen and the airway was secured using the TriTube and flow-controlled ventilation was delivered throughout the procedure using the Evone ventilator. This avoided an awake or emergency tracheostomy, with the associated theoretical risk of tumour seeding, allowed for excellent gas exchange throughout and permitted the surgeons to maintain a closed system during much of the procedure, including during fashioning of the stoma. When traditional laryngectomy tubes are used, this process ordinarily involves multiple extubations and apnoeic periods. Furthermore, the small subglottic tube allowed intra-operative assessment of the extent of the subglottic tumour, facilitating curative en bloc resection.