A ventricular assist device (VAD) is an electromechanical device for assisting cardiac circulation, which is used either to partially or to completely replace the function of a failing heart. The function of VADs is different from that of artificial cardiac pacemakers; some are for short-term use, typically for patients recovering from myocardial infarction (heart attack) and for patients recovering from cardiac surgery; some are for long-term use (months to years to perpetuity), typically for patients suffering from advanced congestive heart failure.
VADs are distinct from artificial hearts, which are designed to assume cardiac function, and generally require the removal of the patient’s heart. Moreover, VADs are designed to assist either the right ventricle (RVAD) or the left ventricle (LVAD), or to assist both ventricles (BiVAD). The type of ventricular assistance device applied depends upon the type of underlying heart disease, and upon the pulmonary arterial-resistance, which determines the workload of the right ventricle.
The left-ventricle assistance device (LVAD) is the most common device applied to a defective heart (as it is sufficient in most cases -the right side of the heart is then often already able to make use of the heavily increased blood flow-), but when the pulmonary arterial-resistance is high, then an (additional) right-ventricle assistance device (RVAD) might be necessary to resolve the problem of cardiac circulation. If both a LVAD and a RVAD is needed a BiVAD is normally used, rather than a separate LVAD and an RVAD.
Normally, the long-term VAD is used as a bridge to transplantation (BTT)—keeping the patient alive, and in reasonably good condition, and able to await the heart transplant outside of the hospital. Other “bridges” include bridge to candidacy, bridge to decision, and bridge to recovery. In some instances VAD’s are also used as destination therapy (DT). In this instance, the patient shall not undergo heart transplantation and the VAD is what the patient will use for the remainder of his life.
Bleeding is the most common postoperative early complication after implantation or explantation of LVADs, necessitating reoperation in up to 60% of recipients. The implications of massive blood transfusions are great and include infection, pulmonary insufficiency, increased costs, right heart failure, allosensitization, and viral transmission, some of which can prove fatal or preclude transplantation.When bleeding occurs, it impacts the one year Kaplan-Meier mortality. In addition to complexity of the patient population and the complexity of these procedures contributing to bleeding, the devices themselves may contribute to the severe coagulopathy that can ensue when these devices are implanted.
Because the devices generally result in blood flowing over a non-biologic surface, predisposing the blood to clotting, there is need for anticoagulation measures. One device, the Heart Mate XVE, is designed with a biologic surface derived from fibrin and does not require long term anticoagulation (except aspirin); unfortunately, this biologic surface may also predispose the patient to infection through selective reduction of certain types of leukocytes.
- 1. https://www.medscape.com/viewarticle/703484
- 2. https://en.wikipedia.org/wiki/Ventricular_assist_device
- 3. https://www.ahajournals.org/doi/full/10.1161/circheartfailure.114.001391
- 4. https://www.TheindiaGK.com/
By – Assistant Professor – Mr. Akbar Nawaz
Department of Nursing
Uttaranchal College of Education
Uttaranchal (P.G.) College Of Bio-Medical Sciences & Hospital