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Background Major vascular (VAC) and life-threatening or major bleeding (LT/MB) complications still represent one of the most frequent adverse outcomes of percutaneous transfemoral TAVR (TF-TAVR) and are associated with an increased risk of mortality. Ultrasound guidance technique allows to puncture in the non-calcified central and horizontal segment of common femoral artery. However the clinical impact of ultrasound (US)-guidance has never been studied in TF-TAVR in comparison of standard fluoroscopic guidance and could explain the lack of adoption of US guidance. We sought first to evaluate in our study the impact of US-guidance on the vascular and bleeding complications. Methods US-guidance for vascular access was implemented as the default approach in our institution in June 2013 for all TF-TAVR and was applied by all operators after a short training course. Thus, we defined three period and groups of consecutive patients according to the method of percutaneous puncture (fluoroscopic or US-guidance) and the generation of THV (2nd or 3rd gen.). US-guided-2nd gen. group: TF-TAVR with 2nd generation THV and performed via US-guidance. This group refers to the period patients from June 2013 to November 2014 (n=119). Fluo-guided-2nd gen. group: The last TF-TAVR with 2nd gen. THV and performed via fluoroscopic guidance (n=119). US-guided-3rd gen. group: Patients implanted with 3rd gen. THV (SAPIEN 3, Evolut R) from November 2014 to December 2018 while US-guidance was systematic for all TF-TAVR (n=308). Patients performed with US-guidance were 1:1 successfully matched with 95 patients performed with fluoroscopic guidance (fluo-guided group) with propensity-score (10 variables). We separately analyzed the consecutive patients of the US-guided-3rd gen. group. Results After propensity-matching, resulting in similar baseline characteristics, all the vascular and bleeding complications were reduced in the US-guided-2nd gen. group compared to Fluo-guided-2nd gen. group with respectively: VAC (6.3% vs 16.8%; OR=0.31; 95% CI: 0.12–0.85; p=0.023); LT/MB (22.1% vs 6.3%; OR=0.24, CI: 0.09–0.63; p=0.004); and VAC related to vascular access (12.6 vs 4.2%; OR=0.31; CI: 0.10–1.01; p=0.052). We also observed a reduction of the mean fluoroscopic time (1753±620 min vs 1228±405 min; p In the US-guided-3rd gen. group (n=308), the US-guided puncture achieved a rate of VAC of 3.2% (CI: 1.6–5.9) and of LT/MB of 3.6% (CI: 1.8–6.3). In the overall population (n=546), we observed that LT/MB (p=0.02) was associated with a 1.7-fold increase of mortality risk. Conclusion The present study is the first and the largest to evaluate the impact of US-guidance in TF-TAVR. We demonstrated that US-guided cannulation is able to reduce the risk of vascular and bleeding complications. These data endorses US-guidance as the standard method of puncture for TAVR.

Background Several mechanisms are suspected to thrombocytopenia under Extracorporeal Membrane Oxygenation (ECMO) such as platelet-consumption or sepsis. Shedding of glycoprotein-(GP)Ibα is a recently identified mechanism of platelet clearance. ECMO generates high shear stress forces that could impact GPIbα-shedding. We hypothesized that ECMO continuous-flow devices could directly induce thrombocytopenia through shear-induced GPIbα-shedding. Aims Determine if ECMO induce GpIb-shedding in vitro and in vivo and determinates the kinetic evolution of platelet-count and GpIb-shedding after patient's implantation. Methods Platelet GPIbα-shedding was first investigated in vitro using a high-shear pump loop model. Plasma with normal platelet count (plasma-NPC) was obtained by dilution of platelet-rich plasma obtained from healthy donors in fresh-frozen-plasma. Samples were collected before and after (5, 30, 60 and 180 min) perfusion at 37°C of plasma-NPC at intermediate and high speed (2.6 and 3.6 L min–1 respectively, n=4 each). Platelet count and GPIbα-shedding were next investigated in 20 ECMO patients before/after implantation (WITECMO trial) and in 20 healthy volunteers. The geometric mean-fluorescence-intensity (gMFI) of platelet GPIbα (PE-staining) and GPIX (FITC-staining) was measured with a Navios flow cytometer (Beckman Coulter, Miami, FL). Results are expressed as GPIbα/GPIX gMFI-ratio. Results A significant time-dependent loss of GPIbα/GPIX gMFI-ratio was already apparent after 30 min in vitro and was significantly more pronounced at high-speed compared to intermediate-speed (pANOVA Figure 1. A. Significant time-dependent loss of platelet GPIbα/GPIX gMFI-ratio (pANOVA