Several types of LVAD devices have been developed, but most of them pull blood through a tube inserted into the left ventricle, then pump the blood through another tube into the aorta. The LVAD assembly itself is placed beneath the heart, in the upper part of the abdomen. An electrical lead (a small cable) from the LVAD penetrates the skin. The lead attaches the LVAD to an external control unit and to the batteries that power the pump. While working, LVADs make hissing/pumping sounds.
Modern LVADs are entirely portable. They allow patients to be at home and to engage in many normal activities.
LVADS are used in three clinical situations:
- In some patients with heart failure, insertion of an LVAD device can allow a damaged left ventricle to "rest" and to repair itself. Examples in which the underlying cardiac problem can often improve include heart failure after cardiac surgical procedures, or with major acute heart attacks, or with acute myocarditis.
- LVADs can be used as a "bridge to transplant" in people with severe chronic heart failure. That is, it can help ease the work of the heart in people who are waiting for heart transplantation.
- LVADs can be used as "destination therapy" in people with severe end-stage heart failure who are not candidates for transplantation (because of other factors such as age, kidney disease, or lung disease), and who have an extremely poor prognosis without mechanical support. In these patients, the LVAD is the treatment; there is little reasonable expectation that the LVAD can ever be removed.
The safety of LVADs has been greatly improved over the years, and the companies that design them have worked very hard to shrink their size to make them suitable for small adults. (Previously, the size of LVADs greatly limited their usefulness.) But there are still many problems associated with LVADs. These include:
- LVADs require meticulous daily maintenance, and careful monitoring to make sure they are always attached to a good power source. So the patient - or family members - must be able to cope with the chronic demands that will be placed upon them.
- Serious bloodstream infections still occur in up to 25% of patients with LVADs, and these infections are often fatal.
- Significant bleeding problems occur in a substantial minority of patients.
- The risk of stroke (from blood clots) is between 10& and 15% per year.
Whether to use an LVAD as "destination therapy" is a particularly difficult decision, because in that case, there is little hope of ever being able to remove the device. In the largest clinical trial conducted to date using LVADs as a destination therapy, only 46% of LVAD recipients were both alive and stroke-free at two years.
The decision to use the LVAD as a temporary device (for potentially reversible heart disease, or as a bridge to transplant), while still difficult, is not quite as daunting.
Even with the problems that remain with LVADS, these devices offer a realistic hope to many patients with end-stage heart failure who would have had no hope just a decade ago. Several companies are still working diligently to improve LVADs technology, to make these devices safer and more convenient to use.
Rose, EA, Gelijns, AC, Moskowitz, AJ, et al. Long-term use of a left ventricular assist device for end-stage heart failure. N Engl J Med 2001; 345:1435.
Bruckner, BA, Stetson, SJ, Perez-Verdia, A, et al. Regression of fibrosis and hypertrophy in failing myocardium following mechanical circulatory support. J Heart Lung Transplant 2001; 20:457.