[Hemodynamic effects of positive end-expiratory pressure]. / Gli effetti emodinamici della pressione positiva di fine espirazione.

The application of a positive end-expiratory pressure (PEEP), the cornerstone of noninvasive ventilation (NIV), causes hemodynamic changes in the cardiovascular system. To understand the benefits of NIV it is necessary to resume concepts of cardiovascular physiology and pathophysiology about cardiac function determinants, venous return, ventricular interdependence and heart-lung interaction, and to understand how PEEP interacts with them. The hemodynamic effects of PEEP are mediated by the increase in transpulmonary pressure, which results in increased pulmonary vascular resistance and in an attending small reduction of venous return in conditions of euvolemia, in a substantial reduction of left ventricular afterload and a potential positive effect on left ventricular stroke volume.The aim of this review is to describe how the application of PEEP does not necessarily induce detrimental hemodynamic effects, but may decrease oxygen consumption and improve cardiac performance. These effects can justify the use of NIV in hemodynamically unstable patients.

Impact of postdilatation on performance of bioresorbable vascular scaffolds in patients with acute coronary syndrome compared with everolimus-eluting stents: A propensity score-matched analysis from a multicenter "real-world" registry.

BACKGROUND: Safety and efficacy of bioresorbable vascular scaffolds (BRS) and the role of postdilatation on outcome in acute coronary syndrome (ACS) patients compared with those of everolimus-eluting stents (EES) remain unknown. The aim of the study is to compare the safety and efficacy of BRS with EES in ACS and to investigate the role of BRS postdilatation. METHODS: Consecutive ACS patients undergoing BRS implantation in 8 centers were com-pared with those with EES before and after propensity score matching. Major adverse cardiac event (MACE), myocardial infarction, and target lesion revascularization (TLR) were the primary endpoint. Sensitivity analysis was performed according to postdilatation after BRS implantation. We enrolled 303 BRS and 748 EES patients; 215 from each group were com-pared after matching, and 117 (55.2%) BRS patients were treated with postdilatation. RESULTS: After a median follow-up of 24.0 months, MACE rates were higher in BRS patients than in EES patients (9.3% vs. 4.7%, p < 0.001), mainly driven by TLR (6.1% vs. 1.9%, p < 0.001). Stent thrombosis increased in the BRS group (2.8% vs. 0.9%, p = 0.01). How-ever, after sensitivity analysis, MACE rates in BRS patients with postdilatation were signifi-cantly lower than in those without, comparable to EES patients (6.0% vs. 12.6% vs. 4.7%, p < 0.001). The same trend was observed for TLR (3.4% vs. 8.4% vs. 1.9%, p < 0.001). Stent thrombosis rates were higher in both the BRS groups than in EES patients (2.6% vs. 3.2% vs. 0.9%, p = 0.045). CONCLUSIONS: Postdilatation appears effective when using BRS in ACS patients. MACE rates are comparable to those of EES, although scaffold thrombosis is not negligible. Randomized prospective studies are required for further investigation.

Bioresorbable Scaffold vs. Second Generation Drug Eluting Stent in Long Coronary Lesions requiring Overlap: A Propensity-Matched Comparison (the UNDERDOGS study).

BACKGROUND: Randomized clinical trials on bioresorbable scaffolds (BRS) enrolled patients with simple coronary lesions. The present study was sought to give preliminary findings about safety of BRS implantation in overlap in long coronary lesions. METHODS: From June 2012 to January 2015, we prospectively collected data from 162 consecutive patients receiving overlapping BRS implantation in the 16 participating institutions. We applied a propensity-score to match BRS-treated patients with 162 patients receiving second generation drug eluting stents (DES) in overlap. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization. RESULTS: DOCE rate did not significantly differ between the two groups (5.6% in BRS group vs. 7.4% in DES group, HR 0.79, 95%CI 0.37-3.55, p=0.6). Also stent/scaffold thrombosis did not differ between groups (1.2% in BRS group vs. 1.9% in DES group, p=0.6). Occurrence of procedural-related myocardial injury was significantly higher in the BRS group (25% vs. 12%, p=0.001), although it was not related to DOCE (HR 1.1, 95%CI 0.97-1.2, p=0.2). Imaging techniques and enhanced stent visualization systems were significantly more employed in the BRS group (p=0.0001 for both). Procedure length, fluoroscopy time and contrast dye amount were significantly higher in the BRS group (p=0.001, p=0.001 and p=0.01, respectively). CONCLUSIONS: Overlapping BRS utilization in long coronary lesions showed a comparable DOCE rate at 1year if compared to second generation DES. Further and larger studies are on demand to confirm our findings.