Ventricular Assist Devices

Some diseases of your heart can affect its function to pump blood to various body organs as in heart failure. At certain stages of your heart failure, your physician might suggest a type of treatment which can help your heart to pump blood. This is can be ventricular assist device (VAD).

Before explaining how VAD works, you can go ahead and take a look on how your heart works  and how it beats.

Heart Disease and using a VAD:

If you develop heart failure, your heart pumping function will be affected and you will start complaining of symptoms of heart failure. This includes shortness of breath, easy fatigue, cough and frothy sputum which can be sometimes tinged with blood as well as nausea and vomiting. The first line of therapy prescribed by your physician will be medical treatment to relieve your symptoms. Diuretics, ACE inhibitors and digoxin are frequently used. In some cases, heart surgery such as coronary artery bypass grafting or replacing a damaged heart valve can help to relieve symptoms and improve heart function. When medical and surgical solutions fail or no longer help, your physician can recommend a Ventricular Assist Device.

What Is a Ventricular Assist Device (VAD)?

A VAD is nothing but a pump. It is called a ventricular assist device because it can help the ventricles (pumping chambers) of the heart in pumping blood.

What are the components of a VAD device?

1. A Mechanical pump: depending on the type of VAD implanted, the actual blood pump may be inside or outside of the body
2. 2 tubes that will be attached to the heart surgically. One tube will take the blood from the heart and brings it to the mechanical pump. The other tube will take the blood from the pump and deliver it to the aorta.
3. An electrical power source for the pump
4. A device that controls and monitor the function of the pump

Types of VADs:

1. LVAD: or left ventricular assist device which supports the left ventricle of the heart. It takes blood from the left ventricle and pumps it to the aorta (main artery of the body).
2. RVAD: or right ventricular assist device which supports the right ventricle of the heart. It takes blood from the right atrium and pumps it to the pulmonary artery.
3. BiVAD: supports both the left and right ventricles of the heart.

Who can benefit from a Ventricular Assist device?

1. A patient with end stage heart failure  who is waiting for a heart transplantation but there is still no available heart for him and at the same time his own heart cannot support him till a donor heart is available. In this case a VAD will support his body and will act as a bridge to a transplant.
2. Patients who suffered from heart attack or heart surgery and their hearts are markedly damaged and cannot pump enough blood to maintain your life. If there is a hope that their hearts might recover within one or 2 weeks, a VAD can be used as a bridge to recovery.
3. Patients who are not candidates for heart transplant may be supported on a VAD for life. This is called VAD destination therapy.

A complete medical examination will be performed to make sure that VAD implantation is the best solution for the patient. Blood tests and, x-rays and ultrasounds will be done to make sure that every other organ of your body is well functioning.

Treatment with a ventricular assist device needs careful monitoring. All patients must be well supported with friends or family to ensure successful results.  Before VAD implantation, patients should identify family members who can be there and help while the patient is being supported by the device. This includes bringing patient to hospital appointments and attending education classes about how to deal with and help the patient with VAD

Surgical implantation of a VAD:

This is performed by a cardiac surgeon under complete general anesthesia and usually takes 4 - 6 hours. The general procedure is outlined below:

Anesthesia:

The anesthesiologist will insert Intravenous lines through which sleeping drugs are injected and arterial line in your hand which monitor your pressure continuously. After you are asleep, the anesthesiologist will insert a tube through your mouth into your windpipe. The breathing tube will be connected to a ventilator which will breathe for you while you are asleep. A urinary catheter (called a Foley catheter) will be inserted through your urethra into your bladder to drain urine. Once all of the necessary tubes and lines are in place, the surgery can begin.

Surgery:

1. Your  sternum (breastbone) will be opened by a sternal saw so the surgeon can access the heart.

2. your heart is then connected to the  heart and lung machine which will perform the functionof your heart and lungs during surgery. By keeping  blood away from the heart, the surgeon can easily operate on your heart.

3. The surgeon will then sew in the tubes which will connect to the blood pump of the VAD. For an LVAD, the surgeon will make a hole in the left ventricle and insert the first tube of the VAD which will bring the blood to the pump. The tube is fixed in place with sutures. The second tube of the VAD which will deliver the blood from the pump to the aorta is then sewn to the aorta. For an RVAD, tubes are sewn into the right atrium and pulmonary artery.

4. When the pump is designed to be on the inside of the body, the surgeon will make a pocket in the abdominal wall just below the heart. The pump will be placed inside this pocket and the skin is closed over it. If the pump is on the outside of the body, the tubes attached to the heart will be tunneled out of the body through incisions in the skin.

5. Next, the surgeon attaches the tubes to the VAD pump and turns on the pump. Blood begins to flow out of the heart into the VAD. Your surgeon will adjust the settings on the

pump to ensure it is appropriately supporting your heart.

6. Finally, the breastbone and chest incision are closed.

What will happen after the operation?

After surgery you will be taken to the Intensive Care Unit. You will gradually wake up. When you are fully awake and can breathe on your own, the breathing tube will be removed and you will be disconnected form the respirator.

You can have some pain at the surgical incision site. Sore throat after removal of the breathing tube can also bother you. You can have some bruises and pain at the site of the intravenous and arterial lines.

After your stay in ICU, you will be moved to the Cardiac Surgery Inpatient Unit. At this time you will:

• Be kept on a heart monitor
• Be helped out of bed into a chair for meals
• Be helped to walk 3 times a day

Deep breathing exercises and coughing are also important to speed recovery. Coughing reduces the chance of infections developing in the lungs (pneumonia). Although it may be painful at times, coughing will not disturb the incision.

Your healthcare providers will perform regular dressing changes to your wounds to help prevent infection.

Complications

These include kidney failure, stroke, bleeding, liver dysfunction, and infection, any of which could lead to death. There is also the risk of device failure, which could result in death.

Blood thinners (Anticoagulants)

Blood thinners are used to prevent clots from forming on your  VAD. However, the use of blood thinners also prevents blood from clotting elsewhere in the body. Thus, bleeding could occur with even a very small injury.

Not all VADs require blood thinners. If you leave the hospital on blood thinners, such as Coumadin or aspirin, you will be asked to have frequent blood tests to monitor your level of anticoagulation. Your doctor will review the results of each blood test and may adjust your dosage of blood thinner as needed.

Going Back to Home:

Prior to discharge, you will undergo extensive education to make sure that you can care for yourself and your VAD. Your nurses will teach you how to change dressings and care for the VAD exit site. Prior to going home, a VAD nurse will do a careful inspection for your home to make sure that you will be safe there while using your VAD.

Precautions for VAD

1. The VAD pump is inserted near your stomach, you may feel full faster. Therefore, you may need to eat more frequent smaller meals.
2. Drink plenty of fluids.
3. Avoid being active in very hot or very cold temperatures.
4. You cannot take a bath until your wound is healed, as water can get inside of the pump and damages it.
5. Do not drive or operate heavy machinery.
6. Do not play contact sports.
7. Stop smoking.
8. Abstain from drinking alcohol since it may affect your ability to respond to system alarms.
9. Do not do magnetic resonance imaging (MRI).