Atherectomy is a procedure used for removing plaque deposits from arteries. They have traditionally been more effective in peripheral than coronary applications. The success of atherectomies has been driven by the limited performance of existing treatments. Often, a blockage is alleviated above the knee, only to have the blood flow deteriorate due to further bottlenecks below the knee. Failure to resolve these vascular limitations can result in critical limb ischemia, ulceration, limb pain or eventual amputation if left untreated.
Atherectomy procedures are used to remove plaque from arteries and reestablish blood flow. Occasionally, atherectomy is referred to as ablation or plaque debulking. Coronary atherectomy devices are used when there is calcification in the arteries, and the procedure is mostly performed in grafts. Atherectomy was originally developed for the treatment of coronary arteries, later expanding to the peripheral market.
Optical coherence tomography (OCT) is an imaging modality that can create extremely high resolution, three-dimensional images of biological tissues, which has proven to be very effective for interventional purposes. While OCT has been used for a number of years in other medical fields, such as in ophthalmology, it has only recently been applied to cardiology. In 2014, only a few OCT systems were approved by the FDA for use in cardiology. However, OCT systems were being used for producing high-resolution images of arteries in a clinical setting since 2006 in Japan and Europe.
Vascular closure devices (VCDs) are used in both the peripheral and coronary markets for minimally invasive cardiovascular therapies, which has created a large market for post-procedural VCDs. The introduction of a catheter into the arterial system, to place a stent for example, is much less traumatic for the patient than a comparable surgical intervention, with only a hole created in the artery (generally the femoral) for access. This access hole will bleed profusely if unmanaged, and therefore some form of vascular closure is required.
Introducer sheaths facilitate the insertion of devices, such as guidewires and catheters, for use in interventional procedures. They are tube-shaped and are generally inserted by nurses. Introducer sheaths can also simplify the application of patches and closure devices at the end of procedures to allow hemostasis to occur. Introducer sheaths are sold in a wide range of sizes to fit patient requirements. They need to have kick resistance and an elongated shape that protects vessels from injuries. In addition, introducer sheaths need to have a transparent structure to allow visualization.
The vast majority of IVUS catheters are used immediately before, during or after an angioplasty procedure. Intravascular ultrasound (IVUS) catheters are used in conjunction with minimally invasive cardiovascular procedures. Procedures utilizing IVUS catheters must be performed in catheterization laboratories (cath labs) that have an IVUS console. These consoles are typically integrated into the cath lab infrastructure and are not portable.
Interventional catheters are used by physicians in procedures for the placement of devices such as stents and balloons. There is a large variety of catheters, and their use depends on the size, shape and curvature of the lesion. Cardiologists tend to choose catheters based on their guidewire selection. Interventional catheters must be rigid without being stiff, because the device must adapt itself to the curvature of certain arteries.
Interventional guidewires are often the first type of device to cross an arterial lesion. For this reason, the choice of guidewire is extremely important in order for a procedure to be successful. Interventional guidewires used for coronary applications can be classified into two general types: conventional and specialty guidewires.
Coronary diagnostic screenings, or angiography procedures, utilize X-ray images for the visualization of arteries and chambers of the heart. A contrast agent is inserted into the patient’s veins in order to screen and monitor blood flow during a procedure. The contrast agent travels through the patient’s body via a diagnostic catheter, whose placement at the opening of the coronary arteries is facilitated through the aid of a guidewire.
Thrombectomy is the process by which an intravascular catheter is used to remove or aspirate obstructing particles from the bloodstream. Thrombosis is a disease state that occurs when dislodged blood clots or thrombi block the normal flow of blood through a vessel, causing complications, such as myocardial infarction or stroke. Most thrombi are produced when vulnerable plaque ruptures and the fragments are released into the bloodstream. The intravascular coagulation of blood cells is primarily responsible for the development of thrombi.
A chronic total occlusion (CTO) occurs in an artery when all blood flow is blocked for more than three months, which causes the blood to flow through smaller vessels, as well as angina. If a guidewire cannot be passed through a lesion, it will not be possible to deploy a stent, a percutaneous transluminal coronary angioplasty (PTCA) balloon or any plaque-debulking device.
The first devices used in the field of interventional cardiology were percutaneous transluminal coronary angioplasty (PTCA) balloon catheters. If not for subsequent restenosis occurrences, they would still be the only device necessary for atherosclerosis treatment. Restenosis was the major problem plaguing interventional cardiology before stents were developed.
The primary uses of balloon-inflation devices are to inflate dilation balloons for stent placement as well as to inject contrast agents for use in diagnostic procedures. Balloon-inflation devices usually consist of a syringe, and sometimes a pressure gauge and a tube to connect the inflation device to the balloon catheter. Balloon-inflation devices are commonly designed to be inflated and deflated with one hand, allowing them to be operated very easily by just one person.
Transmyocardial revascularization (TMR) is a surgically performed laser-based heart treatment procedure in which transmural channels are made in the heart muscle. Many scientific experts believe that these procedures encourage new vessel formation, also known as angiogenesis. TMR therapy is approved for patients suffering from chronic or severe angina. The American Heart Association (AHA) estimates that approximately 9.8 million Americans experience angina symptoms.
Ventricular assist devices (VADs) are used for aiding a failing heart by supplementing the pumping function of the heart. VADs are often used in patients with advanced heart failure (HF). HF is a chronic disease that occurs when degeneration of the heart muscle reduces the pump power of the heart, which causes the heart to become too weak to pump blood at a level sufficient to meet the bodys demands. The condition may be caused by arterial and valve diseases or cardiomyopathy, which is disease of the heart muscle itself. Other conditions such as high blood pressure or diabetes may also lead to HF.
The human heart contains four valves: the mitral valve, tricuspid valve, aortic valve and pulmonary valve. The mitral valve is most prone to regurgitation, which is a condition where blood is funneled back into the left atrium of the heart. Mitral regurgitation (MR) can either be caused by a congenital defect or myxomatous degeneration of the valve. Individuals with MR can suffer from atrial fibrillation, heart muscle dysfunction and even sudden death caused by cardiac arrest. In the U.S., there are just over
4 million people that may have MR, with only a minority actually diagnosed. The standard of care for MR is open surgery and/or the use of annuloplasty rings.