Role of myocardial T1 mapping in arrhythmogenic right ventricular cardiomyopathy

Background

T1 mapping by cardiovascular magnetic resonance (CMR) is an accurate tool to assess myocardial extracellular space with wider clinical applications in the aetiological characterization of cardiomyopathies. The aims of the study were to explore a possible role of myocardial T1 mapping in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and in first-degree relatives at risk and to investigate the possible relationship between left ventricular (LV) involvement at CMR and ECG features.

Methods

Thirty patients with ARVC (47% males, mean age 42±22 years) and 59 first-degree relatives who did not fulfil ARVC diagnostic Task Force criteria, underwent full diagnostic work-up including CMR with native and post-contrast T1 mapping.

Results

The CMR was abnormal in 26 (86%) patients with ARVC. The RV was affected in isolation in 13 (43%) patients. Prior to T1 mapping assessment, 2 (7%) patients exhibited isolated LV involvement and 11 (36%) patients showed features of biventricular disease. Left ventricular involvement was manifested as detectable LV late gadolinium enhancement (LGE) in 12 out of 13 cases. According to pre-specified septal T1 mapping thresholds, 11 (37%) patients showed abnormally high native T1 values. Myocardial T1 mapping was higher than normal in 5 (17%) patients who would have been classified as exhibiting a normal LV by conventional imaging. The proportion of patients with abnormal T1 values was similar in patients with or without LGE. Myocardial T1 mapping was higher than normal in 22 (37%) of the 59 first-degree relatives.

Conclusions

Native and/or post contrast myocardial T1 values are raised in almost half of patients with ARVC and in a similar proportion of unaffected first-degree relatives. T1 mapping offers the potential for early detection of LV involvement in patients with ARVC and in first-degree relatives at risk.

Funding Acknowledgement

Type of funding source: None

Association between minimum inhibitory concentration, beta-lactamase genes and mortality for patients treated with piperacillin/tazobactam or meropenem from the MERINO study

INTRODUCTION

This study aims to assess the association of piperacillin/tazobactam and meropenem minimum inhibitory concentration (MIC) and beta-lactam resistance genes with mortality in the MERINO trial.

METHODS

Blood culture isolates from enrolled patients were tested by broth microdilution and whole genome sequencing at a central laboratory. Multivariate logistic regression was performed to account for confounders. Absolute risk increase for 30-day mortality between treatment groups was calculated for the primary analysis (PA) and the microbiologic assessable (MA) populations.

RESULTS

320 isolates from 379 enrolled patients were available with susceptibility to piperacillin/tazobactam 94% and meropenem 100%. The piperacillin/tazobactam non-susceptible breakpoint (MIC > 16 mg/L) best predicted 30-day mortality after accounting for confounders (odds ratio 14.9, 95% CI 2.8 - 87.2). The absolute risk increase for 30-day mortality for patients treated with piperacillin/tazobactam compared with meropenem was 9% (95% CI 3% - 15%) and 8% (95% CI 2% - 15%) for the original PA population and the post-hoc MA populations, which reduced to 5% (95% CI -1% - 10%) after excluding strains with piperacillin/tazobactam MIC values > 16 mg/L. Isolates co-harboring ESBL and OXA-1 genes were associated with elevated piperacillin/tazobactam MICs and the highest risk increase in 30-mortality of 14% (95% CI 2% - 28%).

CONCLUSION

After excluding non-susceptible strains, the 30-day mortality difference was from the MERINO trial was less pronounced for piperacillin/tazobactam. Poor reliability in susceptibility testing performance for piperacillin/tazobactam and the high prevalence of OXA co-harboring ESBLs suggests meropenem remains the preferred choice for definitive treatment of ceftriaxone non-susceptible E. coli and Klebsiella.

Potential for children with intellectual disability to engage in cognitive behaviour therapy: the parent perspective

BACKGROUND

This study aimed to obtain the opinions of parents and carers of children with intellectual disability (ID) as to whether cognitive behaviour therapy (CBT) could be useful for their children.

METHODS

A mixed qualitative and quantitative method was employed. Twenty-one carers of children aged 10 to 17 having borderline to moderate intellectual functioning responded to an online questionnaire. Participants were provided with information about CBT and asked to respond to open-ended questions. Quantitative data pertained to questions about their child's ability to identify and describe thoughts, feelings and behaviours. Thematic analysis of responses was conducted using an inductive method of identifying themes from the qualitative data collected.

RESULTS

Five themes emerged from the qualitative analysis: Emotional Attunement (i.e. parent's understanding and recognition of their child's emotions), Role of the Therapist (i.e. ways therapists could facilitate the intervention), Role of the Parent (i.e. ways parents could engage in the therapy process), Anticipated Obstacles (i.e. what may get in the way of the therapy) and Suggested Adaptations for Therapy (i.e. how CBT can be adapted to suit the needs of children with ID). Seventy-six per cent agreed that their child would be able to engage in CBT with assistance.

CONCLUSIONS

The majority of parents believed that CBT is an intervention that children with ID could engage in, provided the therapy is adapted, and the therapist accommodates their needs.

P5740ACE2 activity level is associated with embolic stroke of undetermined source

Background

ACE2 activity levels correlate with adverse left atrial remodelling in patients with atrial fibrillation (AF). Several biochemical and structural markers have been associated with embolic stroke of undetermined source (ESUS). The relationship between ACE2 activity and ESUS is unknown.

Purpose

Randomised controlled trials failed to demonstrate a clear benefit of oral anticoagulation in an unselected ESUS population. As selective use of oral anticoagulation guided by biomarker risk-profiling may benefit these patients, we evaluated the association between ACE2 activity and ESUS.

Methods

This prospective case control study compared patients with ESUS against a control group matched for vascular risk factors. ESUS was diagnosed following cerebral vascular imaging and 24 hours of cardiac monitoring to exclude AF. Blood samples were collected for measurement of ACE2 activity, D-Dimer and high sensitivity troponin T (hsTnT).

Results

A total of 51 patients in the ESUS group were compared with 47 patients in the Control group. ACE2 activity and D-Dimer levels were significantly higher in the ESUS group. There was a significant but weak positive correlation between ACE2 activity and hsTnT (r=0.20, p<0.05). Left atrial volume index (LAVI) on echocardiography was significantly higher in the ESUS group. On regression modelling adjusting for LAVI, only ACE2 activity remained significant for ESUS, with a 20% rise in odds for every 4 unit increase in ACE2 activity (OR 1.20; 95% CI: 1.01 - 1.36, p=0.04).

Participant characteristics Control (n=47) ESUS (n=51) P value Age (years) 65.65±6.78 67.20±6.89 0.26 Female gender 22 (45.8) 19 (38.0) 0.43 Hypertension 22 (45.8) 24 (48.0) 0.83 Diabetes mellitus 9 (18.8) 12 (24.0) 0.53 CHA2DS2VASc score 2 (1–3) 2 (1–3) 0.50 LA size & Biomarkers   LA volume index (ml/m2) 36.5 (32.6–42.5) 39.1 (36.2–46.0) 0.04   ACE2 (pmol/ml/min) 7.24 (2.66–14.64) 10.16 (4.54–18.80) 0.04   D-Dimer (mg/L) 0.35 (0.3–0.5) 0.40 (0.30–0.60) 0.02   hsTroponin T (ng/L) 7.0 (5–10) 9.00 (6.0–13.5) 0.05 Values are expressed as mean ± standard deviation, median (IQR), or n (%).

Median ACE2 activity

Conclusion(s)

ACE2 activity is associated with ESUS independent of left atrial volume and correlate with elevated Troponin. Further studies are warranted to investigate the utility of ACE2 activity in identifying ESUS patients that may benefit from oral anticoagulation.

Acknowledgement/Funding

This study received project funding from the Eastern Health Foundation

Ankle fusion percutaneous home run screw fixation: Technical aspects and soft tissue structures at risk

INTRODUCTION

The objective of this cadaveric study was to identify the number of attempts necessary for a perfect positioning of the ankle fusion home run screw and the neurovascular and tendinous structures at risk.

METHODS

Eleven cadaveric limbs were used. Guidewires were percutaneously placed into the distal posterolateral aspect of the leg, under fluoroscopic guidance, with the ankle held in neutral position. Malpositioned guidewires were not removed and served as guidance for the following wires. The number of guidewires needed to achieve an acceptable positioning of the implant was noted. Neurovascular and tendinous injuries were assessed, and the shortest distance between the closest guidewire and the soft tissue structures was measured using a precision digital caliper.

RESULTS

Mean number of guidewires needed to achieve acceptable positioning of the implant was 2.34 (SD 0.81, range 2-4). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon 5.35 mm (SD 2.74 mm); peroneal tendons 9.65 mm (SD 5.19 mm); posteromedial neurovascular bundle 12.78 mm (SD 7.14 mm). The sural bundle was in contact with the guide pin in 5/11 specimens (45.5%) and impaled in 3/11 specimens (27.3%). The average distance from the sural nerve bundle was 3.58 mm (SD 2.16 mm).

CONCLUSIONS

The placement of percutaneous ankle fusion home run screws is technically demanding requiring multiple attempts for acceptable placement. Important tendinous and neurovascular structures are in close proximity to the guidewires. The sural bundle was either injured or in direct contact with the guide wire in approximately 73% of the cases. When using a home run screw, a mini-open approach is recommended.

LEVEL OF EVIDENCE

Level V, cadaveric study.