Prognostic assessment following acute myocarditis requires convalescent scanning: neither peak troponin nor index scan T2 signal predicts convalescent late gadolinium enhancement

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiovascular magnetic resonance (CMR) is a key diagnostic investigation in acute myocarditis (1) and permits quantification of late gadolinium enhancement (LGE) and myocardial oedema.  Follow-up CMR imaging is recommended to check for persistence of scar and oedema (2).  Persistent late gadolinium enhancement is associated with a worse prognosis (3). It is not known whether all patients require follow-up scanning or whether the initial scan can provide useful information to identify which patients need convalescent assessment. 

Purpose

In this study we considered whether extent of troponin elevation, extent of T2 elevation and initial late gadolinium enhancement burden predicted long-term late gadolinium enhancement at follow-up.

Methods

Index and follow-up CMR scans of consecutive patients presenting with a diagnosis of acute myocarditis between 2019 and 2020 across three hospitals were included. Inclusion criteria were: follow-up scan within 9 months of the index scan, CMR with LGE imaging and T2 mapping, and acute myocarditis being the primary diagnosis of the index scan. Myocardial T2 values in the area affected by myocarditis and percentage of LV myocardium showing late enhancement (using a threshold-based full height half width or manual region of interest strategy) were extracted.

Results

20 patients were included in the study (80% male; mean age 37 years). Mean interval between the index and follow-up scan was 4.1 months.  Peak troponin level during the acute illness was not associated with the proportion of LV myocardium affected by LGE in the index scan (R^2 <0.01) (Figure 1A). Myocardial T2 values in the first scan were not associated with the proportional resolution in LGE between the index and follow-up scans (R^2 0.02) (Figure 1B). The mean change in LGE was -61.7% (+/-22.8%) but the initial LGE burden did not predict the proportional degree of improvement in LGE between scans (R^2 <0.01)(Figure 1C).

Conclusions

The extent of troponin elevation and initial CMR phenotype was not a good predictor of the burden of long-term late gadolinium enhancement.  Although most cases showed improvement in LGE scar burden between index and follow-up imaging, neither peak troponin level during the acute episode, nor T2 values at the first CMR scan were predictive of initial or change in scar burden. Serial CMR assessment is required to identify those patients who have residual long-term scarring.

Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015

REASONS FOR PERFORMING STUDY

Pleural effusion (PE) is reported to occur most commonly secondary to bacterial pneumonia or lung abscesses, with neoplastic effusions contributing the minority of cases. The majority of these reports originate from America and Australia, where long distance transport of horses, a recognised risk factor, appears to occur more frequently. Anecdotally, neoplastic PE is more commonly diagnosed in the UK.

OBJECTIVES

To describe the causes of PE in horses resident in the UK, and to identify potential markers that can help differentiate between infectious and neoplastic causes of PE.

STUDY DESIGN

Retrospective clinical study.

METHODS

Medical records from 4 referral hospitals in southern England were searched for horses diagnosed with PE. Information gathered from medical records included signalment, diagnosis (infectious vs. neoplastic), admission physical examination and biochemical findings, and characteristics of the effusion (volume, cell count, total protein [TP] concentration). Statistical comparisons were made between the neoplastic and infectious group using appropriate testing.

RESULTS

Seventy horses were identified, of which 28 (40%) were neoplastic and 42 were infectious. Horses with infectious effusions were significantly younger (median 7 vs. 13 years; P = 0.002) and had significantly smaller volumes of pleural fluid drained at admission (9.8 vs. 32.3 l; P<0.001). Horses with infectious PE had a significantly higher rectal temperature (38.6 vs. 38.2°C; P = 0.03), fibrinogen concentration (7.8 vs. 5.7 g/l; P = 0.02) and serum amyloid A concentration (223 vs. 104 mg/l; P = 0.02). Pleural fluid characteristics identified a significantly greater cell count and TP concentration in horses with infectious PE (47 x 10(9)/l vs. 3.4 x 10(9)/l; P<0.001; 54 vs. 31 g/l; P = 0.001).

CONCLUSIONS

These results suggest that in the UK neoplastic effusions account for a greater proportion of PE than previously reported. A large volume of PE in an older horse with a low cell count and TP concentration should increase the index of suspicion of neoplasia. Ethical animal research: This was a retrospective study of clinical cases. Explicit owner informed consent for inclusion of animals in this study was not stated.

SOURCE OF FUNDING

None. Competing interests: None declared.

Plasma free fatty acids do not provide the link between obesity and insulin resistance or β-cell dysfunction: results of the Reading, Imperial, Surrey, Cambridge, Kings (RISCK) study

AIMS

To investigate the relationship between adiposity and plasma free fatty acid levels and the influence of total plasma free fatty acid level on insulin sensitivity and β-cell function.

METHODS

An insulin sensitivity index, acute insulin response to glucose and a disposition index, derived from i.v. glucose tolerance minimal model analysis and total fasting plasma free fatty acid levels were available for 533 participants in the Reading, Imperial, Surrey, Cambridge, Kings study. Bivariate correlations were made between insulin sensitivity index, acute insulin response to glucose and disposition index and both adiposity measures (BMI, waist circumference and body fat mass) and total plasma free fatty acid levels. Multivariate linear regression analysis was performed, controlling for age, sex, ethnicity and adiposity.

RESULTS

After adjustment, all adiposity measures were inversely associated with insulin sensitivity index (BMI: β = -0.357; waist circumference: β = -0.380; body fat mass: β = -0.375) and disposition index (BMI: β = -0.215; waist circumference: β = -0.248; body fat mass: β = -0.221) and positively associated with acute insulin response to glucose [BMI: β = 0.200; waist circumference: β = 0.195; body fat mass β = 0.209 (P values <0.001)]. Adiposity explained 13, 4 and 5% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively. After adjustment, no adiposity measure was associated with free fatty acid level, but total plasma free fatty acid level was inversely associated with insulin sensitivity index (β = -0.133), acute insulin response to glucose (β = -0.148) and disposition index [β = -0.218 (P values <0.01)]. Plasma free fatty acid concentration accounted for 1.5, 2 and 4% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively.

CONCLUSIONS

Plasma free fatty acid levels have a modest negative association with insulin sensitivity, β-cell secretion and disposition index but no association with adiposity measures. It is unlikely that plasma free fatty acids are the primary mediators of obesity-related insulin resistance or β-cell dysfunction.

Blood culture status in mature horses with diarrhoea: a possible association with survival

REASONS FOR PERFORMING STUDY

The incidence and implications of positive blood cultures in mature horses with diarrhoea is unknown. The diagnosis of bacteraemia may alter treatment and prognosis.

HYPOTHESIS

The proportion of horses with diarrhoea that are blood culture positive is higher than previously assumed and a positive blood culture has a negative impact on survival.

METHODS

Blood cultures were taken at admission and 24 h after admission from 31 mature horses with diarrhoea.

RESULTS

Nine (29%) horses were blood culture positive within 24 h of admission. Organisms isolated included Corynebacterium spp. (n = 6), Streptococcus spp. (n = 2), Pantoea agglomerans (n = 1), Gram-negative rod (n = 1), Bacillus spp. (n = 1) and yeast (n = 1). Horses with positive blood cultures were significantly less likely to survive. Prior treatment with antimicrobial drugs had no significant effect on blood culture status. Horses with positive blood cultures had a significantly higher heart rate, packed cell volume (PCV) and plasma potassium concentration at admission, and a higher PCV and lower total plasma protein concentration 24 h after admission.

CONCLUSIONS

Positive blood cultures occur more frequently than previously reported, and may have a negative impact on survival in horses with diarrhoea.

POTENTIAL RELEVANCE

Results of blood cultures may be useful in formulating a prognosis for horses with diarrhoea. Further research is required to determine the effect of antimicrobial treatment on outcome.

Airtraq vs standard laryngoscopy by student paramedics and experienced prehospital laryngoscopists managing a model of difficult intubation

Two consecutive, randomised, cross-over trials compared intubation success rates in third-year paramedic students and experienced prehospital practitioners using the Airtraq or a Macintosh laryngoscope with flexible stylet in a manikin model of a Cormack and Lehane grade III/IV laryngoscopic view. First-time intubation rates for the Macintosh and Airtraq for students were 0/23 (0%) vs 10/23 (44%) (44% difference, 95% CI 26-63%, p < 0.001) and for experienced laryngoscopists were 14/56 (25%) vs 47/56 (84%) (59% difference, 95% CI 42-72%, p < 0.0001), respectively. First-time oesophageal intubation rates for students were 15/23 (65%) vs 3/23 (13%) (-52% difference, 95% CI -25 to -72%, p < 0.001) and for experienced practitioners 9/56 (16%) vs 0/56 (0%) (-16% difference, 95% CI -9 to -28%, p = 0.0014). Student paramedics and experienced prehospital laryngoscopists managing a manikin model of a grade III/IV view had increased first-time intubation rates and had lower rates of oesophageal intubation with the Airtraq compared with a standard laryngoscope.

Use of the Airtraq laryngoscope in a model of difficult intubation by prehospital providers not previously trained in laryngoscopy

This study evaluated the ability of prehospital providers who had no previous training in intubation, to use an Airtraq laryngoscope to intubate a manikin model of a Cormack and Lehane grade III/IV view. Volunteers attending the Australian College of Ambulance Professionals conference, Adelaide, in November 2006 received approximately 5 min of Airtraq training. First-time intubation success rate was 26/33 (79%) (95% CI 61-91%); oesophageal intubation rate was 0/33 (0%) (95% CI 0-11%); median time to intubation was 17 s (IQR 10-25 s (range 5-30 s)); and median subject-rated difficulty of use score was 21 out of a maximum of 100 (IQR 7.5-35.5 (range 1-65)). Pre-hospital providers without previous laryngoscopy training achieved high first-time intubation success rates when managing a model of a grade III/IV difficult intubation with an Airtraq laryngoscope. Users evaluated it as easy to use and achieved intubation within an acceptable breath-to-breath interval.