Resonetics laser micromachining capabilities help in the fabrication of several types of cardiovascular devices.
Embolic Protection Devices
Embolic protection devices are used in vascular intervention procedures to capture dislodged emboli. These embolic events may occur during a stenting procedure such as saphenous vein graft (SVG) or carotid artery stent procedure, as well as other vascular interventions such as a heart valve replacement. Polymer-based embolic protection filters, fabricated as 2-D filter screens or 3-D “socks,” contain thousands of laser-drilled perfusion holes, which are large enough to permit blood flow through the filter but small enough to capture emboli that, if left unattended, could cause an embolic stroke or pulmonary embolism.
Balloon Aspiration Devices
Balloon aspiration devices, placed proximal to the lesion, mechanically remove the emboli. These devices may momentarily stop blood flow to aspirate the emboli. There are no micro-pores here, but like in many interventional devices, laser stripping or ablation is used to remove a polymer layer of a guide catheter to improve flexibility, especially useful for passage through tortuous vasculature.
Bioresorbable stent or scaffold
Drug-eluting stents, constructed of polymer-coated metal stents, are a significant advancement for the treatment of vascular disease. However, the possibility of late in-stent restenosis and the question of long-term durability and stent fracture opens up opportunities for bioresorbable scaffolds, which are made entirely of bioresorbable polymers (such as polylactides, polyglycolides, and others). Lasers are used to cut the intricate stent pattern fashioned from tubes or flat sheets made of bioresorbable materials.
The resorption characteristics of these scaffolds are dictated by the polymer's properties. As such, conventional laser processes (for fabrication of metal stents) cannot be used due to adverse thermal effects on these polymer properties. UV lasers operating at wavelengths below 300 nm are the preferred lasers for this application.
Newer generation ultrafast lasers are also finding utility in this field on the basis of minimal thermal input to the material (the pulse length is too short to allow heat to start to diffuse into the material) and the potentially greater throughput resulting in a lower product cost.
Another new development in cardiovascular therapies is transcatheter aortic valve intervention (TAVI) or other minimally invasive valve replacements or repairs such as to the mitral valve. This alternative to major open heart surgery offers the potential for shorter recovery times and lower healthcare costs.
An adjunct to this technique is the use of embolic protection filters to reduce the risk of stroke from emboli being produced during placement of the valve. Laser micro-hole drilling of polymer films for embolic protection filters is a long-standing laser application; UV excimer laser micromachining is the manufacturing method of choice.