Late onset of new conduction disturbances requiring permanent pacemaker implantation following TAVI

Background: The timing of onset and associated predictors of late new conduction disturbances (CDs) leading to permanent pacemaker implantation (PPI) following transcatheter aortic valve implantation (TAVI) are still unknown, however, essential for an early and safe discharge. This study aimed to investigate the timing of onset and associated predictors of late onset CDs in patients requiring PPI (LCP) following TAVI. Methods and results: We performed retrospective analysis of prospectively collected data from five large volume centres in Europe. Post-TAVI electrocardiograms and telemetry data were evaluated in patients with a PPI post-TAVI to identify the onset of new advanced CDs. Early onset CDs were defined as within 48 hours after procedure, and late onset CDs as after 48 hours. A total of 2804 patients were included for analysis. The PPI rate was 12%, of which 18% was due to late onset CDs (>48 hours). Independent predictors for LCP were pre-existing non-specific intraventricular conduction delay, pre-existing right bundle branch block, self-expandable valves and predilation. At least one of these risk factors was present in 98% of patients with LCP. Patients with a balloon-expandable valve without predilation did not develop CDs requiring PPI after 48 hours. Conclusions: Safe early discharge might be feasible in patients without CDs in the first 48 hours after TAVI if no risk factors for LCP are present

Aspirin with or without Clopidogrel after Transcatheter Aortic-Valve Implantation

BACKGROUND The effect of single as compared with dual antiplatelet treatment on bleeding and thromboembolic events after transcatheter aortic-valve implantation (TAVI) in patients who do not have an indication for long-term anticoagulation has not been well studied. METHODS In a randomized, controlled trial, we assigned a subgroup of patients who were undergoing TAVI and did not have an indication for long-term anticoagulation, in a 1:1 ratio, to receive aspirin alone or aspirin plus clopidogrel for 3 months. The two primary outcomes were all bleeding (including minor, major, and life-threatening or disabling bleeding) and non-procedure-related bleeding over a period of 12 months. Most bleeding at the TAVI puncture site was counted as non-procedure-related. The two secondary outcomes were a composite of death from cardiovascular causes, non-procedure-related bleeding, stroke, or myocardial infarction (secondary composite 1) and a composite of death from cardiovascular causes, ischemic stroke, or myocardial infarction (secondary composite 2) at 1 year, with both outcomes tested sequentially for noninferiority (noninferiority margin, 7.5 percentage points) and superiority. RESULTS A total of 331 patients were assigned to receive aspirin alone and 334 were assigned to receive aspirin plus clopidogrel. A bleeding event occurred in 50 patients (15.1%) receiving aspirin alone and in 89 (26.6%) receiving aspirin plus clopidogrel (risk ratio, 0.57; 95% confidence interval [CI], 0.42 to 0.77; P=0.001). Non-procedure-related bleeding occurred in 50 patients (15.1%) and 83 patients (24.9%), respectively (risk ratio, 0.61; 95% CI, 0.44 to 0.83; P=0.005). A secondary composite 1 event occurred in 76 patients (23.0%) receiving aspirin alone and in 104 (31.1%) receiving aspirin plus clopidogrel (difference, −8.2 percentage points; 95% CI for noninferiority, −14.9 to −1.5; P<0.001; risk ratio, 0.74; 95% CI for superiority, 0.57 to 0.95; P=0.04). A secondary composite 2 event occurred in 32 patients (9.7%) and 33 patients (9.9%), respectively (difference, −0.2 percentage points; 95% CI for noninferiority, −4.7 to 4.3; P=0.004; risk ratio, 0.98; 95% CI for superiority, 0.62 to 1.55; P=0.93). A total of 44 patients (13.3%) and 32 (9.6%), respectively, received oral anticoagulation during the trial. CONCLUSIONS Among patients undergoing TAVI who did not have an indication for oral anticoagulation, the incidence of bleeding and the composite of bleeding or thromboembolic events at 1 year were significantly less frequent with aspirin than with aspirin plus clopidogrel administered for 3 months

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Adiponectin deficiency blunts hypoxia-induced mobilization and homing of circulating angiogenic cells

Aim. We investigated the effects of adiponectin deficiency on circulating angiogenic cell (CAC) mobilization, homing, and neovascularization in the setting of acute myocardial infarction (AMI). Methods & Results. AMI was induced in wild-type (WT) (n=10) and adiponectin knockout (Adipoq−/−) mice (n=7). One week after AMI, bone marrow (BM) concentration and mobilization of Sca-1+ and Lin−Sca-1+ progenitor cells (PCs) were markedly attenuated under Adipoq−/− conditions, as assessed by flow cytometry. The mRNA expression of HIF-1-dependent chemotactic factors, such as Cxcl12 (P=0.005) and Ccl5 (P=0.025), and vascular adhesion molecules, such as Icam1 (P=0.010), and Vcam1 (P=0.014), was significantly lower in the infarction border zone of Adipoq−/− mice. Histologically, Adipoq−/− mice evidenced a decrease in neovascularization capacity in the infarction border zone (P<0.001). Overall, capillary density was positively correlated with Sca-1+ PC numbers in BM (P=0.01) and peripheral blood (PB) (P=0.005) and with the expression of the homing factors Cxcl12 (P=0.013), Icam1 (P=0.034) and Vcam1 (P=0.014). Conclusions. Adiponectin deficiency reduced the BM reserve and mobilization capacity of CACs, attenuated the expression of hypoxia-induced chemokines and vascular adhesion molecules, and impaired the neovascularization capacity one week after AMI