Aim of the present analysis was to collect and pool all available data currently in the literature regarding outcomes and complications of all approved TAVR prosthesis and to assess the transition from first to next generation TAVR devices by directly comparing both in regard of procedure related complications. Transcatheter aortic valve replacement is a well established treatment modality in patients with severe aortic stenosis deemed to be inoperable or at unacceptable risk for open heart surgery. First generation prostheses were associated with a high rate of peri-procedural complications like paravalvular regurgitation, valve malpositioning, vascular complications and conduction disorders. Refinement of the available devices incorporate features to address the limitations of the first-generation devices. A PRISMA checklist-guided systematic review and meta-analysis of prospective observational studies, national and device specific registries or randomized clinical trials was conducted. Studies were identified by searching PUBMED, SCOPUS, Cochrane Central Register of Controlled Trials and LILACs from January 2000 to October 2017. We extracted and pooled data on both mortality and complications from 273 studies for twelve different valves prostheses in a total of 68,193 patients. In second generation prostheses as compared to first generation devices, we observed a significant decrease in mortality (1.47 ± 1.73% vs. 5.41 ± 4.35%; p < 0.001), paravalvular regurgitation (1.75 ± 2.43vs. 12.39 ± 9.38, p < 0.001) and MACE. TAVR with contemporary next generation devices has led to an impressive improvement in TAVR safety driven by refined case selection, improved procedural techniques and increased site experience.

Transcatheter aortic valve replacement has emerged as valuable treatment modality for patients with severe aortic stenosis and an unacceptable risk/benefit ratio for open heart surgery, but particularities specific to TAVR and a rapidly growing number of available TAVR prosthesis make post-procedural assessment of valve function challenging. Aim of the present analysis was to collect and pool all available data currently in the literature regarding normal doppler values for transcatheter prosthetic heart valves and to provide a comprehensive overview. A PRISMA checklist-guided systematic review and meta-analysis of prospective observational studies or national and device specific registries or randomized clinical trials was conducted. Studies were identified by searching PUBMED, SCOPUS, Cochrane Central Register of Controlled Trials and LILACs from January 2000 to March 2017. Out of 240 abstracts, 155 studies reporting echocardiographic parameter for twelve different valves prosthesis in a total of 27,159 patients were in included in this meta-analysis. The means and standard deviations of peak velocity, peak gradient, mean gradient and effective orifice were extracted and pooled from the included studies. The pooled means and standard deviations for all available TAVR prosthesis were classified according to implanted valve size and time since implantation. The present study firstly describes a pooled analysis of normal values for all available TAVR prosthesis in order to empower treating physicians with a reliable tool to perform follow-up echocardiographic assessment in TAVR patients and to safely identify patients with prostheses dysfunction.

According to the Berlin Definition of acute respiratory distress syndrome (ARDS), a positive end-expiratory pressure (PEEP) of at least 5 cmH2O is required to diagnose and grade ARDS. While the Berlin consensus statement specifically acknowledges the role of non-invasive ventilation (NIV) in mild ARDS, this stratification has traditionally presumed a mechanically ventilated patient in the context of moderate to severe ARDS. This may not accurately reflect today’s reality of clinical respiratory care. NIV and high-flow nasal cannula oxygen therapy (HFNO) have been used for managing of severe forms of acute hypoxemic respiratory failure with growing frequency, including in patients showing pathophysiological signs of ARDS. This became especially relevant during the COVID-19 pandemic. The levels of PEEP achieved with HFNO have been particularly controversial, and the exact FiO2 it achieves is subject to variability. Pinpointing the presence of ARDS in patients receiving HNFO and the severity in those receiving NIV therefore remains methodically problematic. This narrative review highlights the evolution of the ARDS definition in the context of non-invasive ventilatory support and provides an overview of the parallel development of definitions and ventilatory management of ARDS. It summarizes the methodology applied in clinical trials to classify ARDS in non-intubated patients and the respective consequences on treatment. As ARDS severity has significant therapeutic and prognostic consequences, and earlier treatment in non-intubated patients may be beneficial, closing this knowledge gap may ultimately be a relevant step to improve comparability in clinical trial design and outcomes.

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