Development, design and experience of the UK Military's return to diving pathway following SARS-CoV-2 infection

After the emergence of the SARS-CoV-2 virus in early 2020, it quickly became clear that symptomatic or asymptomatic infection had the potential to negatively impact on an individual's fitness to dive through effects on the respiratory, cardiovascular or neurological systems. The significance of these effects in the military diving environment was initially unclear due to an absence of data concerning incidence, chronology or severity. In order to safely return divers to the water and maintain operational capability, the UK Military developed a pathway for SARS-CoV-2 positive divers that stratified risk of sequelae and extent of required clinical investigation, while minimising reliance on viral testing and hospital-based investigations. We present this process, provide rationale and support for its design and detail the number of SARS-CoV-2 positive divers who have been returned to full diving fitness following infection of varying degrees of severity.

Return to flying duties of German military pilots after recovery from COVID-19

BACKGROUND

Pilots are working in a unique and exacting environment with hypobaric hypoxia and acceleration forces. In military flying, missions are often challenging with possible combat scenarios and in remote areas with impaired infrastructure.

METHODS

We analysed all German military pilots and pilot candidates with confirmed SARS-CoV-2 infection, who have all been evaluated prior to their return to flying duties between April 2020 and January 2022 by the German Air Force Centre of Aerospace Medicine. Symptoms, comorbidities, scope of investigations, examination results, vaccination status and aeromedical disposition are described.

RESULTS

90 pilots (82 active pilots and 8 pilot candidates) with a median age of 35 years (IQR 15 years) were included. 78 pilots (87%) reported symptoms, with median duration of 6 days. Symptoms included influenza-like symptoms (70.0%), headache (45.6%), impaired physical fitness (37.8%), anosmia/ageusia (36.7%), fever (27.8%), exertional dyspnoea (8.9%), memory and concentration disorders (4.4%), diarrhoea (3.3%) and dyspnoea at rest (2.2%). Only one pilot (1.1%) was hospitalised, two (2.2%) required outpatient treatment. All pilots were allowed to return to unrestricted flying duties after the assessment, with eight (8.9%) reporting ongoing mild symptoms.

CONCLUSION

Due to their demanding working environment, pilots, and other high-hazard employees, should undergo medical evaluation prior to return to their duties to exclude ongoing symptoms and the development of post-acute COVID-19 or post-COVID-19 syndrome. The scope of examinations may depend on the severity of the disease, comorbidities, the vaccination status, the predominant SARS-CoV-2 variant and the type of aircraft flown.

The temporal analysis of elite breaststroke swimming during competition

Breaststroke is the only competitive stroke characterised by propulsive discontinuity. It is consequently paramount that swimmers optimally coordinate limb movements in order to maintain the highest average velocity possible. The present study aimed to investigate the temporal patterns of elite breaststroke swimmers. 50 m long-course competition footage of (1) 20 male 100 m races, (2) 24 female 100 m races, (3) 15 male 200 m races, and (4) 27 female 200 m races from 2018 to 2020 were digitised and analysed. Six points within each stroke cycle were identified and used to calculate 15 temporal parameters. Analyses revealed multiple temporal pattern differences between groups based on sex and race distance. It is recommended that coaches individualise swimmers' breaststroke temporal patterns based on individual needs, strengths, and morphological characteristics.

Does industry funding differ between men and women in electrophysiology and devices research?

Funding Acknowledgements

Type of funding sources: None.

Background

A significant gender bias has been identified in cardiology. Industry funding may be important developing electrophysiology (EP) and devices research. Such funding leads to potential conflicts of interest (COI) which must be disclosed on research presentations. There is limited evidence whether the gender bias in cardiology extends to industry funding of research.

Purpose

To assess whether COI disclosures in EP and devices presentations at the ESC Annual Congress differ between men and women.

Methods

Recorded presentations from the Arrhythmia & Devices section of ESC Annual Congresses 2016-2020 were assessed. Presentations were excluded if the original presentation contained no slides, it was a panel discussion, it was a non-scientific presentation, or part of the presentation was missing. Presentations with multiple speakers were also excluded. Chi-squared and Mann-Whitney U tests were used to assess differences between groups for dichotomous and continuous data respectively.

Results

Of 1,153 presentations assessed, 999 were suitable for inclusion. Women made up 22% (n = 221) of presenters. There was no difference in whether COI declaration slides were missing between women (5.9%, n = 13) and men (7.6%, n = 56), p = 0.38. In those with COI disclosure slides (n = 927), women declared significantly lower median number of COIs (0, IQR 0-3) compared with men (2, IQR 0-8), p < 0.0001. In contrast, women spent a greater time-per-word on their COI disclosure slides (250ms, IQR 125-375ms) compared with men (200ms, IQR 118-333ms), p < 0.0001.

Conclusions

Women made up a minority of presenters in EP/devices talks at the ESC annual congress. Women were less likely to have COIs which may suggest that they are less likely to receive industry funding. Despite this, women spent a greater amount of time-per-word on their COI slides. The lower number of declared COIs in women highlights another potential area of gender bias in cardiology that needs further investigation so that it can be addressed.

Defence Medical Rehabilitation Centre (DMRC) COVID-19 Recovery Service

Coronavirus disease 2019 (COVID-19) causes significant mortality and morbidity, with an unknown impact in the medium to long term. Evidence from previous coronavirus epidemics indicates that there is likely to be a substantial burden of disease, potentially even in those with a mild acute illness. The clinical and occupational effects of COVID-19 are likely to impact on the operational effectiveness of the Armed Forces. Collaboration between Defence Primary Healthcare, Defence Secondary Healthcare, Defence Rehabilitation and Defence Occupational Medicine resulted in the Defence Medical Rehabilitation Centre COVID-19 Recovery Service (DCRS). This integrated clinical and occupational pathway uses cardiopulmonary assessment as a cornerstone to identify, diagnose and manage post-COVID-19 pathology.

CT in planning transcatheter aortic valve implantation procedures and risk assessment

For surgical aortic valve replacement, the Society of Thoracic Surgeons score (STSS) is the reference standard for the prediction of operative risk. In transcatheter aortic valve implantation (TAVI) though, where the procedure itself is minimally invasive, the traditional risk assessment is supplemented by CTA. Through a consistent approach to the acquisition of high-quality images and the standardised reporting of annular measurements and adverse root and vascular features, patients at risk of complications can be identified. In turn, this may allow for a personalised procedural approach and treatment strategies devised to potentially reduce or mitigate this risk. This article provides a systematic and standardised approach to pre-procedural work-up with computed tomography angiography (CTA) and explores the current state of evidence and future areas of development in this rapidly developing field.

P3384Left atrial appendage pseudo-thrombus as an independent risk factor for ischaemic stroke in patients with non-valvular atrial fibrillation

Background

Left atrial appendage (LAA) pseudo-thrombus is a well recognised phenomenon in patients with atrial fibrillation (AF) undergoing cardiovascular CT (CCT). The clinical significance of LAA pseudothrombus on CCT, in those with non-valvular AF (NVAF) is unknown.

Objectives

To determine the association of LAA pseudo-thrombus in those with NVAF and ischaemic stroke.

Methods

216 consecutive patients with NVAF, referred for CCT (with both standard and 60-second delayed acquisitions) were assessed for the LAA pseudo-thrombus, LA and LAA dimensions and morphology, cardiovascular risk factors, treatment, and ischaemic stroke risk

Results

Mean age (±SD) was 65.0±10.6 years (range 32–89) and 70.8% were male. LAA pseudo-thrombus was present in 59/216 (27%) patients. Ischaemic stroke is more frequent with increasing age (OR 1.10 (95% confidence intervals (CI) 1.06, 1.16), p<0.0001), vascular disease (3.21 (1.18, 8.75) p=0.023), pseudo-thrombus on CCT (4.18 (1.97, 8.88) p<0.0001), cauliflour LAA morphology (4.93 (1.06, 22.09) p=0.042), and increased LAA ostial area: LAA tortuosity (4.64 (1.57, 13.71) p=0.006).

Age (1.09 (1.03, 1.15) p<0.0001), vascular disease (4.07 (1.19, 13.98) p=0.026), cauliflour LAA morphology (15.01 (2,93, 76.81) p=0.001) and pseudothrombus on CCT (3.62 (1.38, 9.50), p=0.009) were independently associated with ischaemic stroke. Pseudothrombus remained an independent risk factor even after CHA2DS2-VASc was included (3.21 (1.22, 8.41), p=0.018).

Conclusion

Pseudothrombus on CCT is a common finding in patients with NVAF and has a strong positive association with ischaemic stroke. Inclusion of pseudothrombus on CCT in risk assessment is additive to CHA2DS2-VASc in prediction of ischaemic stroke risk in patients with NVAF.

P3654Location of the coronary origins in transposition patients following anatomical repair: Implications for invasive coronary angiography and intervention

Background

Surgical repair of transposition of the great arteries (TGA) is most commonly via the arterial switch operation (ASO). This involves translocation of the aorta and pulmonary trunk, typically with anastomosis of the branch pulmonary arteries anteriorly (LeCompte manoeuvre) and re-implantation of the coronary arteries onto the posterior neo-aorta. As such, the position of the coronary ostia may differ from their expected locations.

Purpose

To use ECG-gated CT angiography to describe the anatomic position of coronary ostia in post-switch TGA patients guiding potential catheter interventions in this population.

Methods

All post ASO patients who underwent CT imaging between 2008–2018 were identified. Patients with complex anatomy such as double outlet right ventricle were excluded. The positions of the coronary ostia were measured in degrees from vertical on a double-oblique reconstruction in the aortic valve plane. Ostium positions were compared to those of patients with no congenital heart disease via Watson's two-sample test of homogeneity for circular data. Angular dispersion was compared between groups via the Wallraff test. P<0.05 indicated statistical significance.

Results

Of 206 adult patients with TGA and ASO followed in our adult congenital heart disease centre, 38 (18.4%) had CT imaging available for analysis during the study period (mean age 24±6.8, 75% male).

The control group consisted of 15 patients investigated for chest pain (mean age 54±15.1, 73% male). In the control group, the right and left coronary ostia arose at a mean angle of −19 and +125 degrees from vertical (figure 1a). This was significantly different to the mean ASO coronary ostia clustered at mean angles of −70 and +29 degrees from vertical (Watson p<0.001) (figure 1b, with stenosis at the left coronary anastomosis).

There was no significant difference in spread of left ostia (Rho 0.9 vs 0.99, p=0.12), but right ostia were significantly more variable in ASO patients than controls (0.71 vs 0.96, p=0.003).

Figure 1

Conclusions

Coronary ostial positions in the neo-aorta of post-ASO patients differ significantly from those of normal controls, with considerable variability, especially in right coronary position. CT can demonstrate coronary ostia in 3D space and derive appropriate tube angles to guide catheterisation in post-operative congenital cardiac patients, optimise catheter selection, reduce catheterisation tome, radiation and contrast dose.

P2243CTCA alone demonstrates superior diagnostic accuracy, prognostic utility and is less expensive than CTCA combined with subsequent multi-modality functional imaging in patients with ischaemic symptoms

Background

The evaluation of suspected ischaemic symptoms incorporates multi-modality anatomical and functional imaging tests. The 2016 update to the UK's NICE guidelines recommends CT coronary angiogram (CTCA) first line in patients without known coronary artery disease. Additive multi-modality functional imaging may provide synergistic diagnostic and prognostic information.

Purpose

To investigate the diagnostic accuracy, prognostic utility and cost of CTCA combined with subsequent multi-modality functional testing versus (vs) CTCA alone.

Methods

772 consecutive patients were referred to a single UK tertiary centre with symptoms suggestive of ischaemia. 657 individuals (“CTCA group”) underwent CTCA alone, and 115 individuals (“Combined group”) underwent CTCA and then either perfusion cardiac MRI (n=25), stress echocardiogram (n=16), or myocardial perfusion scintigraphy (n=74). Patients underwent invasive angiography (n=79) +/− revascularisation at the discretion of the referring clinician. All readers and operators were aware of previous imaging findings. Revascularised patients (n=52) were excluded from long term follow-up. The remaining patients were followed-up for a mean of 38.1±17.4 months and the incidence of major adverse cardiovascular events (MACE) recorded. Costs were derived from the NICE guidelines.

Results

Baseline characteristics were similar between groups. The Combined group underwent significantly more invasive angiograms than the CTCA group (29.6% vs 6.8%, p=0.0001) with no significant difference in the rate of revascularisation (73% vs 67%, p=0.72). Mean time from CTCA to angiogram was significantly longer in the Combined group (81.2 vs 38.1 days, p=0.0001). Both sensitivity and specificity were lower in the Combined group than in the CTCA group (sensitivity: 70% vs 93%, specificity: 75% vs 100%). The rate of long term MACE was significantly higher in the Combined group (8.7% vs 2.6%, p=0.0026). Multivariate analysis of CTCA and functional imaging findings found that CTCA-derived four vessel aggregate stenosis score (0–12) was the strongest predictor of MACE for the whole cohort (OR 4.4, p<0.0001), and also for those with negative functional tests (OR 3.9, p<0.0001). Per patient, a combined strategy was more expensive than CTCA alone (£1551 vs £368, p=0.0001).

CTCA and functional data vs outcomes

Conclusions

Combining multi-modality functional testing with CTCA increased costs but did not improve diagnostic accuracy or long term outcomes. Further reductions in both MACE and unnecessary invasive angiography are desirable; CT-derived functional data such as FFRCT may be implicated.

Image reconstruction in cardiovascular CT: Part 2 - Iterative reconstruction; potential and pitfalls

The use of IR in CT previously has been prohibitively complicated and time consuming, however improvements in computer processing power now make it possible on almost all CT scanners. Due to its potential to allow scanning at lower doses, IR has received a lot of attention in the medical literature and has become a successful commercial product. Its use in cardiovascular CT has been driven in part due to concerns about radiation dose and image quality. This manuscript discusses the various vendor permutations of iterative reconstruction (IR) in detail and critically appraises the current clinical research available on the various IR techniques used in cardiovascular CT.

Transferring patients with Ebola by land and air: the British military experience

The Ebola epidemic of 2014/2015 led to a multinational response to control the disease outbreak. Assurance for British aid workers included provision of a robust treatment pathway including repatriation back to the UK. This pathway involved the use of both land and air assets to ensure that patients were transferred quickly, and safely, to a high-level isolation unit in the UK. Following a road move in Sierra Leone, an air transportable isolator (ATI) was used to transport patients for the flight and onward transfer to the Royal Free Hospital. There are several unique factors related to managing a patient with Ebola virus disease during prolonged evacuation, including the provision of care inside an ATI. These points are considered here along with an outline of the evacuation pathway.

Managing palpitations in the military patient

'Palpitations' include a broad range of symptoms relating to the perception of abnormal activity of the heart. They may reflect an underlying arrhythmia or a hyperawareness of normal cardiac activity caused by stress or anxiety. The challenge to a clinician assessing patients with palpitations is to assess the likely cause of symptoms, to stratify the individual patient risk and to choose the correct management strategy delivered with appropriate urgency. The young military population, subject to increased exposure to environmental stress, is at an increased risk of palpitations. Due to the distracting nature of this symptom and the frequently sudden and unheralded onset, a common consequence is medical downgrading. This article will provide a guide to assessing the heterogeneous group presenting with palpitations and how to both establish the cause and identify the correct treatment for each patient in a timely manner.

Challenges of managing toxic alcohol poisoning in a resource-limited setting

We present a series of patients with profound metabolic acidosis admitted to the Role 3 Medical Treatment Facility, Camp Bastion, Afghanistan, in 2012. A police service breath alcohol analyser, calculation of the osmolar gap and urine microscopy assisted in diagnosing methanol poisoning. The challenge of diagnosing and managing toxic alcohol poisoning in this resource-limited setting is discussed. We believe this is the first description of using a breath alcohol analyser to assist a diagnosis of methanol poisoning.

The effect of applying NICE guidelines for the investigation of stable chest pain on out-patient cardiac services in the UK

BACKGROUND

The National Institute for Health and Clinical Excellence (NICE) recently released guidelines for the investigation of chest pain of recent onset. There is no published data regarding their impact on out-patient cardiac services.

AIM

This study was undertaken to assess the likelihood of coronary artery disease (CAD) in Rapid Access Chest Pain Clinic (RACPC) patients and the resultant investigation burden if NICE guidance was applied.

METHODS

Five hundred and ninety-five consecutive patients attending two RACPCs over 6 months preceding release of the NICE guidelines [51% male; median age 55 (range 22-94) years] were risk stratified using NICE criteria and the resultant investigations evaluated.

RESULTS

One hundred and six (18%) patients had a likelihood of CAD <10%, 123 (21%) between 10% and 29%, 175 (29%) between 30% and 60%, 141 (24%) between 61% and 90% and 50 (8%) >90%. NICE would have recommended 443 (74%) patients for no cardiac investigation, 10 (2%) for cardiac computed tomography (CCT), 69 (12%) for functional cardiac testing and 73 (12%) for invasive angiography. Relative to existing practice, there would have been a trend towards reduced functional cardiac testing (-24%, P = 0.06), no significant change in CCT (43%, P = 0.436) and a significant increase in invasive angiography (508%, P < 0.001). The cost of investigations recommended by NICE would have been £15,881 greater than existing practice.

CONCLUSION

This study suggests patients attending RACPC will have a greater likelihood of CAD than predicted by NICE. Differences between recommended investigations and existing practice will guide investment in cardiac services. Individual hospitals should assess their RACPC cohorts prior to implementing the NICE guidelines.

The consequences of applying NICE chest pain guidelines to an acute medical population: a role for cardiac computed tomography

BACKGROUND

Cardiac computed tomography (CCT) is a well-validated investigation for the non-invasive assessment of coronary artery disease (CAD). The National Institute for Clinical Excellence (NICE) have recently released guidelines incorporating CCT into the diagnostic algorithm for chest pain of recent onset.

AIM

To assess the frequency of eligibility for CCT in medical admissions with suspected cardiac chest pain using criteria defined by NICE.

DESIGN

A retrospective, observational study, set in a teaching hospital acute medical unit.

METHODS

A total of 198 consecutive patients admitted over a 4-month period with suspected cardiac chest pain (57% male; mean age 63.5 years) were assessed for eligibility for CCT based on NICE guideline criteria.

RESULTS

Of the 198 patients admitted, 65 (33%) patients were excluded by a raised troponin I or ischaemic ECG changes; 100 (51%) patients were excluded by pain categorized as non-anginal and 171 (86%) patients were excluded by a modified Diamond Forrester score outside the range 10-29%. Applying NICE criteria to this population ultimately resulted in 2 (1%) patients recommended for CCT, 12 (6%) for functional cardiac testing and 17 (9%) for invasive angiography.

CONCLUSION

Applying current NICE guidelines for chest pain of recent onset to medical admissions results in a lesser uptake of CCT than functional testing and invasive angiography. If the NICE guidelines are revised to include patients with an intermediate pre-test probability of CAD, CCT may have a greater role.

Influence of the 3D inverse dynamic method on the joint forces and moments during gait

The joint forces and moments are commonly used in gait analysis. They can be computed by four different 3D inverse dynamic methods proposed in the literature, either based on vectors and Euler angles, wrenches and quaternions, homogeneous matrices, or generalized coordinates and forces. In order to analyze the influence of the inverse dynamic method, the joint forces and moments were computed during gait on nine healthy subjects. A ratio was computed between the relative dispersions (due to the method) and the absolute amplitudes of the gait curves. The influence of the inverse dynamic method was negligible at the ankle (2%) but major at the knee and the hip joints (40%). This influence seems to be due to the dynamic computation rather than the kinematic computation. Compared to the influence of the joint center location, the body segment inertial parameter estimation, and more, the influence of the inverse dynamic method is at least of equivalent importance. This point should be confirmed with other subjects, possibly pathologic, and other movements.

Military sports and rehabilitation medicine

This article summarises the presentations at the Sports Medicine and Rehabilitation Study Day held by the Haywood Club at The Medical Society of London on 21 September 2006. The event was attended by over 100 serving and retired DMS personnel and included talks on a diverse range of subjects from the newly established speciality of Sports and Exercise medicine, the role of physiotherapy, exercise therapy and podiatry, core stability, tendon disorders, anterior knee pain, and the management of chronic pain.

New and Emerging Concepts in Travel Medicine

The following article summarises the proceedings of the Travel Medicine Study Day run by the Haywood Club Tri-Service Medical Society at the Medical Society of London on 23 November 2006. The event was attended by over 50 serving and retired DMS personnel, including nurses, MSO's and medical officers and included talks on the historical contribution of the military medical services to the evolution of tropical medicine, the changing face of worldwide illness and insights into the behaviour of travellers that may increase their risk of illness.

Transarterial embolization of a cervical dural arteriovenous fistula. Presenting with subarachnoid hemorrhage

SUMMARY

We describe a case of a 75-year-old man who presented with acute onset of headache and subarachnoid hemorrhage and initial cerebral angiography was deemed "negative". In retrospect, a faint contrast collection was present adjacent to the right vertebral artery at the C1 level suspicious for a small dural arteriovenous fistula (dAVF). Follow-up angiography with selective microcatheter injections of the right vertebral artery and C1 radicular artery confirmed a complex dAVF with characteristically specific venous drainage patterns associated with a subarachnoid hemorrhage presentation. Subsequently, the cervical dAVF was treated with superselective glue embolization resulting in complete occlusion. Cervical dAVFs are extremely rare vascular causes of subarachnoid hemorrhage. Both diagnostic angiography and endovascular treatment of these lesions can be challenging, especially in an emergent setting, requiring selective evaluation of bilateral vertebral arteries and careful attention to their cervical segments. Although only a single prior case of a cervical dAVF presenting with subarachnoid hemorrhage has been successfully treated with embolization, modern selective transarterial techniques may allow easier detection and treatment of subtle pathologic arteriovenous connections.

Echocardiography in the critically ill: current and potential roles

BACKGROUND

The use of echocardiography in the critically ill presents specific challenges. However, information of direct relevance to clinical management can be obtained relating to abnormalities of structure and function and can be used to estimate pulmonary arterial and venous pressures.

DISCUSSION

Investigation of the consequences of myocardial ischaemia, valvular dysfunction and pericardial disease can be facilitated, and changes characteristic of specific conditions (e.g. sepsis, pulmonary thromboembolism) detected. Echocardiography can also be used to monitor the effects of therapeutic interventions.

CONCLUSIONS

The applications of echocardiography in the critical care setting (excluding standard peri-operative echocardiography for cardiac surgery) are reviewed, with particular emphasis on the assessment of cardiac physiology.

Development of a noninvasive ultrasound color M-mode means of estimating pulmonary vascular resistance in pediatric pulmonary hypertension: mathematical analysis, in vitro validation, and preliminary clinical studies

BACKGROUND

Accurate determination of pulmonary vascular resistance (PVR) is an important component in the evaluation and treatment of pediatric patients with pulmonary hypertension. We developed a novel technique, based on the concept of flow propagation, to estimate PVR noninvasively. The hypothesis is that changes in PVR cause changes in the velocity propagation (Vel(prop)) within the main pulmonary artery and that Vel(prop) can be quantified using color M-mode imaging.

METHODS AND RESULTS

We tested the hypothesis using mathematical modeling, in vitro experiments, and preliminary clinical studies. The mathematical model showed that pressure and velocity tracings are closely correlated in time and that 6 to 18 ms time resolution was needed to resolve propagation times within typical main pulmonary artery lengths (2 to 5 cm). The in vitro experiments demonstrated that it was feasible to use color M-mode to measure Vel(prop) and that Vel(prop) correlated well with downstream resistance [y=(-1.01x)+22.77; R=0.96]. The method was then evaluated on patients undergoing acute pulmonary reactivity testing (n=22 measurements). Good correlation between Vel(prop) and PVR was found [y=(-1.71x)+26.0; R=0.90; SEE=2.41].

CONCLUSION

This newly developed method promises to be useful in the noninvasive evaluation of adults and children with pulmonary hypertension.