Question

Compare contrast the four different types of heart pumps in terms of driver, flow, indication, advantages and disadvantages.

Answer 1

1)JARVIK

Held in the hand, the Jarvik 2000 Heart System is a pump is about the size of a C battery. Within its titanium shell sits a direct-current motor and a single moving part: a small, spinning titanium impeller that pumps blood from the heart at up to 7 liters per minute. It can be implanted through an incision in the breastbone (sternotomy) or through a less invasive incision along the rib cage (thoracotomy). The Jarvik 2000 augments the weakened heart's blood output to help restore a normal blood flow throughout the body.

Patients with this device can be discharged from the hospital while they wait for a suitable donor heart. This device is currently undergoing trails for bridge to transplant.

Advantages

There are many significant advantages of the Jarvik 2000 compared to larger VADs. The Jarvik 2000 is small enough to fit inside the left ventricle which is not the case with larger VADs. Larger VADs also require creation of a “pump pocket” which creates a site for discomfort and possible infection. The Jarvik 2000 does not require a pump pocket because of its small size. With only one moving part, it is also totally silent.

• Simplicity
• Manual Controls
• Small Size
• Silent Operation
• Portability

2)

THE HEARTWARE HVAD PUMP

The HeartWare HVAD Pump is surgically implanted in your chest, in a sac around your heart known as the pericardial space. The small size of the pump allows it to be implanted using a smaller incision than required with older VAD technologies.

The HVAD Pump is connected directly to your heart at the bottom of the left ventricle, where it draws oxygen-rich blood through the pump and pushes it into your aorta. Once blood reaches the aorta, it can flow to the rest of the body.

Despite the compact size of the HVAD Pump, it can pump enough blood every minute to decrease heart failure symptoms. Your doctor will program the HVAD Pump so it delivers the right amount of flow for your body’s needs.

The driveline is connected to the pump. The cable that connects the pump to the controller is fed through a small incision in your abdomen.

LIVING WITH THE HVAD SYSTEM

Living with the HVAD System includes managing the equipment that runs the pump.

The controller is a mini computer that monitors the pump. It provides text messages and audible alarms to help you manage the system. The controller runs on two batteries or one battery combined with electricity from a wall or car outlet. Two fully charged batteries can run the controller for 8 to 12 hours. The HVAD System comes with several batteries, a battery charger, and multiple power adapters.

Together, the controller and batteries weigh less than 3.5 pounds (1.6 kg). Carrying packs come in several styles. Each one is designed for easy, hands-free use.

3)

LVAD THERAPY

A left ventricular assist device, or LVAD, is a mechanical device designed to help circulate blood throughout the body when the heart is too weak to pump blood on its own. An LVAD is not an artificial heart, nor is it a heart replacement. An LVAD attaches to the heart and assists—or takes over—the pumping function of your left ventricle, which is the main pumping chamber of the heart.

HOW AN LVAD WORKS

A surgeon places an LVAD inside your body, just below your diaphragm in your abdomen or next to your heart, and attaches it to your left ventricle and aorta (the main artery that carries oxygenated blood from the left ventricle to the entire body). An external, wearable system that includes a small controller and two batteries is attached by an external driveline. The wearable system is either worn under or on top of clothing.

The HeartMate II™ LVAD is indicated for use as a "bridge to transplantation" for patients waiting for a transplant heart and for "destination therapy." Destination Therapy may be an option for people who are ineligible for a heart transplant. The HeartMate II LVAD was the first LVAD device approved by the FDA for Destination Therapy, sometimes called permanent support.

PATIENT-CENTRIC FEATURES

The HeartMate II LVAD is designed for patient comfort and convenience. With its wearable design and several carrying options, the HeartMate II LVAD supports your patients’ lifestyles.

Other features and benefits:

• Provides mean blood flow of up to 10 L/min—equal to that of a healthy heart
• Low-dose anticoagulation regimen
• Safe for air travel*

SAFETY BY DESIGN

The HeartMate II LVAD comes with a lightweight, pocket-sized controller that interfaces with the implanted pump. Its features are designed for safety:

• Backup battery provides at least 15 minutes of full power in an emergency situation
• Prioritized visual alarms provide clear, actionable instructions
• On-screen instructions eliminate the need for guesswork
• Driveline diagnostic checks verify that driveline wires are intact and functional

4) CentriMag left ventricular assist system

The CentriMag left ventricular assist system can be used for perioperative or postcardiotomy circulatory support of the failing heart. The device resides at the patient's bedside, and the cannulae are usually inserted through a midline sternotomy, with the inflow cannula in the left ventricle or right superior pulmonary vein and the outflow cannula in the aorta. In a patient whose chest has been closed and who has a delayed need for temporary mechanical support, a less invasive method of left ventricular assist device cannula insertion is preferred. In these cases, the CentriMag cannulae can be inserted through a right minithoracotomy with the inflow cannula in the right superior pulmonary vein and the outflow cannula in the aorta, with no heparinization. Herein, we describe this approach in a patient who experienced postcardiotomy cardiogenic shock after aortocoronary bypass surgery. This technique may facilitate ambulation and recovery in selected patients.

CentriMag LVAS is quite practical for postcardiotomy circulatory support. Because this system does not require the use of specific cannulae, various cannulation techniques may be used. When weaning of the patient from CPB fails, existing cannulae may be used by simply changing the connections. In our patient, the cannulae were inserted through a right minithoracotomy in order to avoid reopening the sternum. If necessary, the subclavian artery could have been used for outflow return. Because of the CentriMag's versatility of cannulation and the ample flow-rate range (up to 10 L/min), the system may be used in patients of widely varying body sizes. The magnetically levitated impeller eliminates friction and heat within the pump housing, minimizing blood trauma and thrombogenicity.In turn, the reduced thrombogenicity minimizes the amount of anticoagulant therapy that is needed to prevent thrombosis.

Although the CentriMag is designed for short-term use (up to 14 days), we have found that it may be safely used for longer periods. The lack of friction within the pump's drive system eliminates component wear.5 External cannulae in any pump system limit patient mobility and increase infection rates. Nevertheless, the new, less invasive technique described here, which avoids aortic clamping and the need for large doses of heparin, may facilitate pump insertion and, in selected patients, may hasten recovery and increase mobility.