On the Aging Kinetics of a Flame-Resistant AZ91D-1.5%Ca Magnesium Alloy Processed with Ultrasonic Vibration.

The Mg-Al-Zn-Ca system has demonstrated excellent flame resistance and mechanical properties in the as-cast condition. However, the potential of these alloys to be heat-treated, e.g., by aging, as well as the influence of the initial microstructure on the precipitation kinetics, is yet to be comprehensively explored. Ultrasound treatment was applied during the solidification of an AZ91D-1.5%Ca alloy to promote microstructure refinement. Samples from treated and non-treated ingots were subjected to solution treatment at 415 °C for 480 min, followed by aging at 175 °C for up to 4920 min. The results showed that the ultrasound-treated material could reach the peak-age condition in a shorter period than the non-treated one, suggesting accelerated precipitation kinetics and, thus, enhanced aging response. However, the tensile properties showed a decrease in the peak age compared to the as-cast condition, probably due to the formation of precipitates at the grain boundaries that promote the formation of microcracks and intergranular early fracture. This research shows that tailoring the material's as-cast microstructure may positively affect its aging response, shortening the heat treatment duration, thereby making the process less expensive and more sustainable.

Predictors of Residual Right-to-Left Shunt After Percutaneous Suture-Mediated Patent Fossa Ovalis Closure.

OBJECTIVES: This study sought to assess patent fossa ovalis (PFO) anatomy by transesophageal echocardiography (TEE) in patients undergoing percutaneous suture-mediated PFO closure to identify predictors of post-procedural residual atrial right-to-left shunt (RLS). BACKGROUND: Percutaneous suture-mediated PFO closure has been proven to be a safe and effective technique in most PFO patients. METHODS: From June 2016 to October 2019, 247 consecutive patients underwent percutaneous suture-mediated PFO closure at our institution. Of them, 230 (46 ± 13 years of age, 146 women) had complete and technically evaluable pre-procedural TEE. The following parameters in short-axis view were assessed: presence and grade of spontaneous RLS, PFO length and width, presence of atrial septal aneurysm and its maximal bulge, and presence of an embryonic or fetal remnant (Chiari network or Eustachian valve). RESULTS: At the first follow-up transthoracic echocardiography performed between 3 and 6 months from the closure procedure, a residual RLS ≥2 grade was found in 37 (16%) patients. Grade of pre-procedural spontaneous RLS (hazard ratio: 1.99; 95% confidence interval: 1.14 to 3.48; p = 0.016) shunt and PFO width (hazard ratio: 2.52; 95% confidence interval: 1.85 to 3.43; p < 0.001) were both found to be significantly associated with significant residual RLS at multivariable analysis. The presence of atrial septal aneurysm and its maximal bulge and of congenital remnants was not associated with significant residual RLS. CONCLUSIONS: Percutaneous suture-mediated PFO closure is feasible in the majority of septal anatomies; however, PFO >5 mm in width and spontaneous large RLS are less likely to be closed with 1 stitch only.

Concept and practice of transradial 5 French percutaneous treatment of coronary bifurcation lesions.

OBJECTIVES: To assess the efficacy and safety of transradial 5 French percutaneous treatment of coronary bifurcations using conventional devices. BACKGROUND: Radial artery is smaller than femoral artery, and its size may potentially limit transradial intervention, especially when coronary anatomy is not known. METHODS: Patients with bifurcations lesions undergoing transradial 5 French ad hoc revascularization were treated according to provisional side branch (SB) stenting followed by the POT-SB dilation-final POT sequence. Only conventional devices were used. RESULTS: Overall, 80 patients (58 men, 65 ± 10 years) were enrolled. True bifurcations accounted for 64% of cases, with the left anterior descending artery/diagonal branch being the most frequent bifurcation site (n = 37, 46%) and left main coronary artery bifurcation being treated in 6 (8%) patients. Angiographic success was achieved in 78 (97.5%) patients through a 5 French guiding catheter whereas in two cases, a 5-6 French guiding catheter upgrade was required to optimize SB treatment after the main bifurcation vessel have been secured. Overall, procedural success was achieved in all but one patient who had periprocedural necrosis following multivessel PCI. Another patient underwent target bifurcation revascularization because of a critical restenosis in a significant SB yielding an acute coronary syndrome five months after the index procedure. CONCLUSIONS: This study demonstrates the feasibility of transradial 5 French bifurcation intervention with nondedicated devices and preliminary supports its efficacy and safety over a wide range of bifurcation anatomy and complexity.

Safety and Efficacy of Triple Therapeutic Targets with Rivaroxaban after Acute Myocardial Infarction Complicated by Left Ventricular Thrombi in a Case of Nonvalvular Atrial Fibrillation.

We present the complex case of a high-risk patient with nonvalvular atrial fibrillation, who experienced a non-ST elevation myocardial infarction complicated by left ventricular (LV) thrombi and underwent percutaneous coronary intervention with drug-eluting stent implantation. The patient was initially treated with short-term triple therapy including aspirin, clopidogrel, and rivaroxaban 15 mg/die. Following aspirin dropping one month after discharge, the patient continued on dual therapy with clopidogrel and rivaroxaban, and a clinical and imaging follow-up at 6 and 12 months confirmed the LV thrombi resolution, with no thromboembolic episodes and a good safety profile.

Identifying a better strategy for ad hoc percutaneous coronary intervention in patients with anticipated unfavorable radial access: the Little Women study.

BACKGROUND: Transradial percutaneous coronary intervention (PCI) offers important advantages over transfemoral PCI, including better outcomes. However, when there is indication to ad hoc PCI, a 6 French workflow is a common default strategy, hence potentially influencing vascular access selection in patients with anticipated small size radial artery. METHODS: A multidimensional evaluation was performed to compare two ad hoc interventional strategies in women <160cm: a full 6 French workflow (namely 6 French introducer sheath, diagnostic catheters and guiding catheter) with a modified workflow consisting in the use of 5 French diagnostic catheters preceded by the placement of a 6 French sheath introducer and followed by a 6 French guiding catheter use for PCI. RESULTS: Overall 120 women (68±11years) were enrolled in the study. Coronary angiography has been performed using 5 French or 6 French diagnostic catheters in 57 (47.5%) and 63 (52.5%) cases, respectively. Radial spasm and switch to another access occurred more frequently among women who underwent coronary angiography with 6 French rather than 5 French diagnostic catheters (43% vs. 25%, p=0.03 and 2% vs. 11%, p=0.04, respectively). Total time to guidewire lesion crossing was also significantly higher when PCI has been preceded by 6 French rather than 5 French coronary angiography (23±11min vs 16±7min, p=0.013). CONCLUSIONS: In patients with anticipated unfavorable radial access, a workflow consisting in 6 French introducer sheath placement, 5 French coronary angiography, and 6 French coronary intervention is on multiple parameters the most straightforward and effective strategy.

Angiographic and clinical performance of polymer-free biolimus-eluting stent in patients with ST-segment elevation acute myocardial infarction in a metropolitan public hospital: The BESAMI MUCHO study.

OBJECTIVES: This study aimed at assessing the performance of a new generation polymer-free biolimus-eluting stent (BES) in real-world patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Polymers components of early-generation drug-eluting stents have been implicated in the pathogenesis of delayed arterial healing, vessel remodeling, and delayed stent thrombosis. Recently, a novel polymer-free BES has shown excellent clinical performance in clinical trial setting. METHODS: Overall, 175 consecutive patients (64 ± 14 years, 141 men) treated with the BioFreedom (Biosensors Europe, Morges, Switzerland) polymer-free BES because of STEMI were included in this study. The primary endpoint was the rate of major adverse cardiac events (MACE), a composite of cardiac death, recurrent myocardial infarction, and ischemia-driven target vessel revascularization at 1 year follow-up. A subgroup of patients underwent 6-month angiographic follow-up. Dual antiplatelet therapy was prescribed for 12 months after STEMI. RESULTS: At 1 year, the cumulative rate of MACE was 4.6%. One patient (0.6%) had an arrhythmic cardiac death and five (2.9%) had ischemia-driven target vessel revascularization, although only three (1.7%) had target lesion revascularization. Two (1.1%) patients had acute stent thrombosis yielding nonfatal myocardial infarction. In 70 patients (63 ± 14 years, 61 men), quantitative coronary angiography at 6-month follow-up revealed diameter stenosis of 24.1 ± 13.7% and minimal lumen diameter of 2.29 ± 0.56 mm, yielding a late lumen loss of 0.13 ± 0.14 mm. CONCLUSIONS: In real-world setting, implantation of a new-generation polymer-free BES during STEMI is associated with favorable clinical and angiographic results, pointing toward the overall efficacy and safety of the device in complex clinical scenarios.

Effects of reperfusion obtained two to six months after acute myocardial infarction on myocardial electrical stabilization in patients with an occluded infarct-related coronary artery.

To assess the changes in electrical stability markers in patients with previous myocardial infarction after very late reopening of the infarct-related artery, we studied QT dispersion, corrected-QT dispersion, and late potentials before and 1, 3, and 6 months after an attempt at late percutaneous coronary intervention (PCI) in 31 consecutive patients with single-vessel disease (infarct-related artery occlusion or subocclusion) diagnosed > or = 4 weeks after the ST-elevation myocardial infarction. Patients underwent PCI 3.9 +/- 2 months after ST-elevation myocardial infarction. PCI was successful in 24 patients (group A) and unsuccessful in 7 (group B). The 2 groups were similar in clinical and angiographic characteristics, as well as the prevalence of basal late potentials, average QT dispersion, and corrected-QT dispersion. One month after PCI, the successful reperfusion group had a significant 67% decrease in the prevalence of late potentials and average QT dispersion and corrected QT dispersion (51 +/- 9 vs 72 +/- 11 ms, p <0.00001, and 51 +/- 10 vs 76 +/- 15 ms, p <0.00001, respectively). These benefits remained stable at 3 and 6 months after PCI. Conversely, the unsuccessful group did not show any improvement in electrical stability markers after PCI failed. Thus, reperfusion obtained very late after ST-elevation myocardial infarction confers significant electrical stabilization that may contribute to a better outcome in patients with patent infarct-related arteries.