Martha had undergone unsuccessful mitral valve repair. She had ring dehiscence and very poor left ventricular function. Remember transplantation was not an option because she was obese. Re-operation was risky since ventricular function was poor. We considered a percutaneous MitraClip procedure, where a clip is placed on the valve to pull the anterior and posterior leaflet together. This procedure has also been used in patients with dehiscence of an annuloplasty ring. However, we believed the procedure would be technically very complex and would probably effect no more than a moderate reduction of mitral regurgitation. What now?
The light at the end of the tunnel Here is the echo at the end of the surgical procedure. Can you tell which procedure was performed?
If you look closely you can see a cannula stuck in the apex of the left ventricle. This cannula is part of a left ventricular assist device system (LVAD). A Thoratec pump was used to pump blood out of the left ventricle and assist the left ventricle.
How does it work? The cannula in the left ventricle is connected to a continuous flow pump which passes blood to another cannula. This cannula it connected to the ascending aorta. Basically the device serves as a pump that bypasses the left ventricle.
Illustration of how the LVAD (Thoratec pump) works.
A small drive line connects the pump to a portable control unit worn outside the body, through which adjustments can be made. This is where the batteries are located.
Martha holding the LVAD controller.
What the echo shows Patients with such pumps are usually difficult to image. Their left ventricular function is not easily assessed. It also depends on how much “assist” the pump provides. A unique feature in these patients is that the aortic valve does not open. Here is the parasternal short-axis view showing that it stays closed.
This can also be appreciated on the M-mode image below. One only sees a line and not a “box” of the aortic valve, as one would expect in a normal individual.
M-mode view of the aortic root/ aortic valve. No valve motion.
The reason why the valve does not open is quite apparent. Blood leaves the ventricle not through the aortic valve but through the cannula. In fact, patients who have significant aortic regurgitation are no candidates for this procedure. Of course the surgeons also performed mitral valve repair with an annuloplasty ring, which was successful in this case. As you can see, there is no residual mitral regurgitation.
Normal mitral inflow and no mitral regurgitation after repair.
What does this mean for the patient? Martha recovered quickly. She is already out of the bed. With the pump she will be able to resume her daily activities. The battery lasts for about 14 hours so she can wander around freely. We will now wait and see whether the ventricle recovers under the LVAD assistance. If this is the case, the LVAD will be explanted. The second option we have is to bridge her for transplantation. With the LVAD and with better exercise capacity, Martha should be able to loose weight and we should then be able to put her on the transplant list. LVAD pumps are certainly a very good option for many patients with end-stage heart failure. Although the device is not entirely devoid of complications such as infection, bleeding or neurologic events, it prolongs life in these critically ill patients. How long can the LVAD stay implanted? Well, we do not know for sure because newer models such as the ones we use today have not been around for very long. But we do have patients who are under LVAD assistance for several years and still doing fine.
This case might seem exotic to some of you. We want to give you a glimpse into the future as well. We will certainly see more of these devices in the future, especially with the shortage of hearts for transplantation. We echocardiographers have to be prepared and know what to look for. The purpose of the course and our echo material is to prepare you for the real world.