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.
Artificial heart devices can be temporary or permanent mechanical devices that are designed to replace the function of a biological heart. The term artificial heart should not be used for describing ventricular assist devices (VADs). VADs are pumps that assist the heart but are not designed to replace it. Instead, they are used in collaboration with a patients heart. An artificial heart is also distinct from a cardiopulmonary bypass machine (CPB), which is an external device used for providing the functions of both the heart and lungs. CPBs are only used for a few hours at a time, most commonly during heart surgery. Artificial hearts were originally intended to be a permanent replacement for the biological human heart.
Tissue valves, which are also known as bioprosthetic valves, are harvested from either human donors or animal tissue. Human tissue valves can either be obtained from donor cadavers in allograft procedures, or from ones own body in an autograft procedure. Allograft valves may be acquired from deceased family members or anonymous donors. Autograft valves may be obtained through a Ross procedure, whereby part of the pulmonary valve is grafted and harvested into the aortic position. Whether autograft or allograft, human donor valves involve complicated extraction and insertion procedures. Human tissue valves are in limited supply and typically do not function drastically better than xenograft valves.
A patent foramen ovale (PFO) is a defect in the septum between the two atrial chambers of the heart. Specifically, the defect is an incomplete closure of the atrial septum that results in the creation of a flap or a valve-like opening in the atrial septal wall. A PFO is distinct from a secundum atrial septal defect (ASD). A PFO is present in everyone before birth but seals shut in most people. In adults, PFO occurs when the atrial septum, which is responsible for recycling blood during womb development, does not properly occlude after birth. The condition is very common, affecting over 20% of the population. Individuals with PFO are more likely to suffer a stroke and there is evidence that migraines can be a symptom of the condition. Those who have a PFO as well as migraines often experience sensations during their migraine that include shimmering spots, blurred vision and blind spots. There are many cases where PFO patients do not need to undergo surgery and drug treatment and continual monitoring are the only measures that are necessary. However, open surgical and interventional procedures are common in patients who run the risk of having a sudden cardiac arrest.
Remote hemodynamic monitoring devices are implanted into the patient to monitor the blood pressure in the pulmonary artery. The device takes measurements from inside the body and transmits the data to a secure website for clinicians to review. The clinicians are then able to preemptively able to detect heart failure and treat them before symptoms arise.
OPCAB procedures are much harder to perform because the beating heart adds difficulty in performing a bypass on the posterior and lateral walls of the heart. Surgeons have found many ways to stabilize the heart to bypass the necessary arteries. Most commonly, stabilizer and positioner devices are used in surgeries to aid physicians in stabilizing and positioning the heart and arteries.
The majority of coronary artery bypass graft (CABG) procedures are performed with the heart stopped. This type of procedure is termed on-pump coronary artery bypass (ONCAB) because the procedure requires the usage of a cardiopulmonary bypass (CPB). CPB is a technique that temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the body. The CPB pump itself is often referred to as a heart-lung machine. In addition to the heart-lung machine, a complete extracorporeal bypass system is composed of various single-use products, called disposables for the purposes of this report. As disposables come into direct contact with the patients blood, they cannot be reused for safety reasons and must be disposed of and replaced following each procedure.
The left atrial appendage (LAA) is a small pouch in the wall of the left atrium. It is unknown what function the LAA performs.
In patients with normal heart rhythm, the heart contracts with each heartbeat. As the heart contracts, blood is pushed from the left atrial appendage into the left atrium and from the left atrium into the left ventricle.
Mechanical heart valves are prosthetic devices designed to replicate the function of the natural valves of the human heart. Mechanical valves are designed to outlast the patient and some have been stress-tested to last several hundred years. Although mechanical valves are long-lasting and generally only require one surgery for installation, they contribute to an increased risk of blood clot formation. As a result, mechanical valve recipients often take anti-coagulant (blood thinning) drugs such as warfarin for the rest of their lives, which makes the patient more prone to bleeding. Given their durability, mechanical valves are primarily indicated for younger patients and for mitral valve replacement due to its high-pressure gradient. The primary advantage of mechanical over tissue valves is that once a mechanical valve is implanted, they never wear down and rarely need to be replaced. Mechanical valves are made from either pyrolytic carbon or titanium that has been coated with pyrolytic carbon. Pyrolytic carbon is similar to graphite and is used for many biomedical applications. They also can have parts made from Teflon, polyester or polyethylene terephthalate.
Coronary artery bypass graft (CABG) procedures involve bypassing a weakened or damaged artery with another vessel to bypass the blocked and diseased portion of the coronary artery and maintain blood flow. The vessels most often used are the saphenous vein in the leg, the radial artery in the arm or the mammary artery from the chest wall. Vessel harvesting may be performed with an open incision or endoscopically. Endoscopy allows for a small, minimally invasive incision to be made rather than the much larger incision required for open harvesting. Endoscopic vessel harvesting (EVH) devices have become the standard of care for vessel harvesting during CABG procedures performed in the United States. The vessels obtained using EVH devices provide excellent conduit quality and hemostasis results. Furthermore, EVH procedures reduce patient discomfort and scarring as well as recovery time for the patient. This acts to improve patient outcomes and increase overall satisfaction.
Counterpulsation therapy is used during surgery to provide temporary assistance to the heart. Counterpulsation refers to the inflation and deflation of an intra-aortic balloon synchronized with the heartbeat. The therapy increases the hearts output and the supply of oxygen-rich blood to the hearts coronary arteries while reducing the heart muscles workload and its oxygen demand. Counterpulsation is performed using intra-aortic balloon pump (IABP) devices.
Atrial septal defect (ASD) and ventricular septal defect (VSD) are both conditions that involve incorrect blood flow within the heart. ASD is an opening in the muscular tissue that separates the sides of the hearts two upper chambers. Due to blood reflux, the heart is made to work more strenuously and below its optimal level. The condition is more common in females than males and tends to get worse with time. If left untreated, ASD can cause hypertension, heart arrhythmia and even a stroke. As with patent foramen ovale (PFO), ASD can be treated with open-heart surgery, but the operation is highly invasive. ASDs are found in approximately 1 in 1,500 live births and can lead to death if not treated in some cases.
The ECMO market includes disposable products and capital equipment. ECMO products have been in the market for a long time but have only recently started gaining traction. ECMO has experienced a reinvigoration due to positive reports and the stagnation of heart-lung machines in the market. The market is expected to grow as more surgeons view the technique as a better alternative to heart-lung machines.
Anastomosis assist devices (AADs) are used for joining two blood vessels, usually to restore continuity after resection, or to bypass an unresectable disease process. Coronary artery bypass graft (CABG) involves the construction of an alternative path to bypass a narrowed or occluded diseased coronary artery and restore blood flow from the aorta to an area beyond the occlusion. This is accomplished by using harvested veins or arteries as bypass grafts. This harvested vessel is usually the saphenous vein in the leg, the radial artery in the arm or the mammary artery from the chest wall. One end of the harvested vessel is then generally attached to the aorta (proximal anastomosis) and the opposite end is attached to the target coronary vessel on the heart (distal anastomosis). If the mammary artery is used as the bypass graft, it is dissected from the chest wall, leaving the blood inflow end in place, while the opposite dissected end is attached to the target vessel. This provides uninterrupted blood flow and eliminates the need for proximal anastomosis to the aorta. Regardless of the type of vessel used, once in place, these grafts provide sufficient blood flow to bypass the narrowed or occluded portion of the coronary artery.
Annuloplasty is used for restoring an optimal orifice area and shape, providing support and preventing further annular dilatation. Through disease or age, the tissue that supports the heart valves opening, the annulus, can weaken and lose its shape. To repair this condition, a device called an annuloplasty ring or band is sewn around the base of the heart valve to reshape it and give it support. An annuloplasty band or ring is made of durable plastic, metal or fabric and may be flexible or rigid. These rings and bands are designed to hold the natural shape, motion and flexibility of the annulus. An annuloplasty repair procedure usually involves open heart surgery requiring a median sternotomy, but may also be performed minimally invasively via keyhole surgical techniques or percutaneously.