Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material,Design, and Performance

Endovascular stenting has matured into a commonly used treatment for peripheral arterial disease (PAD) due to its minimally invasive nature and associated reductions in short-term morbidity and mortality. The mechanical properties of the superelastic Nitinol alloy have played a major role in the explosion of peripheral artery stenting, with modern stents demonstrating reasonable resilience and durability. Yet in the superficial femoral and popliteal arteries, even the newest generation Nitinol stents continue to demonstrate clinical outcomes that leave significant room for improvement. Restenosis and progression of native arterial disease often lead to recurrence of symptoms and reinterventions that increase morbidity and health care expenditures. One of the main factors thought to be associated with stent failure in the femoropopliteal artery (FPA) is the unique and highly dynamic mechanical environment of the lower limb. Clinical and experimental data demonstrate that the FPA undergoes significant deformations with limb flexion. It is hypothesized that the inability of many existing stent designs to conform to these deformations likely plays a role in reconstruction failure, as repetitive movements of the leg and thigh combine with mechanical mismatch between the artery and the stent and result in mechanical damage to both the artery and the stent. In this review we will identify challenges and provide a mechanical perspective of FPA stenting, and then discuss current research directions with promise to provide a better understanding of Nitinol, specific features of stent design, and improved characterization of the biomechanical environment of the FPA to facilitate development of better stents for patients with PAD.     

Knowledge on types of treatment pressure. A cross-sectional study among mental health professionals

Treatment pressure restricts patients' voluntary and autonomous decisions. Yet interventions involving treatment pressure are widely used in mental health and psychosocial services. This cross-sectional study explored whether mental health professionals' knowledge on five types of treatment pressure (no coercion, persuasion or conviction, leverage, threat, and formal coercion) was associated with sociodemographic, professional and contextual factors. A more positive attitude towards interventions involving treatment pressure was associated with underrating the level of those interventions compared with a predefined default value. The treatment setting and professional group played a minor role in ‘leverage’ and ‘formal coercion’ types of treatment pressure, respectively.