CCTA appears to be a feasible alternative to transoesophageal echocardiography for post-LAA device surveillance to evaluate for device thrombus, residual leak, embolization, position, and pericardial effusion.

BackgroundIt has long been recognized that vitamin D deficiency is associated with muscle weakness and falls. Vitamin D receptor (VDR) is present at very low levels in normal muscle. Whether vitamin D plays a direct role in muscle function is unknown and is a subject of hot debate. Myocyte‐specific deletion of VDR would provide a strategy to answer this question.MethodsMyocyte‐specific vitamin D receptor (mVDR) null mice were generated by crossing human skeletal actin‐Cre mice with floxed VDR mice. The effects of gene deletion on the muscle phenotype were studied in terms of body tissue composition, muscle tissue histology, and gene expression by real‐time PCR.ResultsUnlike whole‐body VDR knockout mice, mVDR mice showed a normal body size. The mVDR showed a distinct muscle phenotype featuring reduced proportional lean mass (70% vs. 78% of lean mass), reduced voluntary wheel‐running distance (22% decrease, P = 0.009), reduced average running speed, and reduced grip strength (7–16% reduction depending on age at testing). With their decreased voluntary exercise, and decreased lean mass, mVDR have increased proportional fat mass at 20% compared with 13%.Surprisingly, their muscle fibres showed slightly increased diameter, as well as the presence of angular fibres and central nuclei suggesting ongoing remodelling. There were, however, no clear changes in fibre type and there was no increase in muscle fibrosis. VDR is a transcriptional regulator, and changes in the expression of candidate genes was examined in RNA extracted from skeletal muscle. Alterations were seen in myogenic gene expression, and there was decreased expression of cell cycle genes cyclin D1, D2, and D3 and cyclin‐dependent kinases Cdk‐2 and Cdk‐4. Expression of calcium handling genes sarcoplasmic/endoplasmic reticulum calcium ATPases (SERCA) Serca2b and Serca3 was decreased and Calbindin mRNA was lower in mVDR muscle.ConclusionsThis study demonstrates that vitamin D signalling is needed for myocyte function. Despite the low level of VDR protein normally found muscle, deleting myocyte VDR had important effects on muscle size and strength. Maintenance of normal vitamin D signalling is a useful strategy to prevent loss of muscle function and size.

Aims: Device surveillance after left atrial appendage (LAA) closure (LAAC) is important to assess device positioning, peri-device leak (PDL) and device-related thrombus (DRT). There are limited data on the role of cardiac CT angiography (CCTA) after LAAC. We therefore sought to compare CCTA to transoesophageal echocardiography (TEE) in patients who successfully underwent LAAC.Methods and results: We report our consecutive series of non-valvular atrial fibrillation patients who underwent LAAC and had CCTA and TEE post LAAC. Prospective cardiac-gated CCTA was performed with the Toshiba 320-detector or Siemens second-generation 128-slice dual-source scanner, and post-processing was performed with IMPAX 3D reformats. Glomerular filtration rate <30 mL/min/1.73 m² was an exclusion for CCTA. Device positioning, PDL or fabric leak, ratio of left atrial (LA) to LAA linear attenuation coefficient, and DRT were analysed. One hundred and two patients underwent LAAC (79 WATCHMAN, 17 Amulet, 6 ACP). Mean age was 76.4±7.5 years, CHADS2 score 3.0±1.3, and CHADS-VASc score 4.6±1.6. CCTA was performed at a mean of 105.2±54.8 days, and TEE at a mean of 124.9±100.3 days post LAAC. LAA patency was observed in 52/100 (52%), with 45 (86.5%) via PDL and seven (13.5%) through fabric leak. Linear attenuation coefficient <100 HU and LA:LAA ratio <0.25 were seen in occluded devices. PDL was only observed in 35/102 (34.3%) on TEE. Mean device compression was greater with sealed devices (11.3±4.3% versus 8.2±4.0%, p<0.001). There was only one DRT, which was observed on both TEE and CCTA.Conclusions: CCTA is a suitable alternative to TEE for device surveillance post LAAC. CCTA was more sensitive than TEE for assessing PDL and can delineate the cause of residual LAA contrast patency.

All 3 imaging modalities correlated with ACP landing zone and WATCHMAN ostium measurements, with CCTA providing the largest measurements, followed by TEE and fluoroscopy.