When an ailing heart needs an extra boost, Froedtert & the Medical College of Wisconsin cardiac specialists turn to the latest generation of ventricular assist devices (VADs) to provide hemodynamic support.
At their most basic, VADs are mechanical pumps that either assist or take over the function of one or both of the ventricles to circulate blood. Depending on the condition of the heart and the goal of treatment, VADs can be short-term or long-term therapy.
Three Distinct Applications
“We use VADs with three defined patient populations,” said Takushi Kohmoto, MD, PhD, surgical director of cardiac transplantation and MCW faculty member. “One, patients with cardiogenic shock or heart failure, as a bridge to recovery. Two, patients awaiting a new heart, as a bridge to transplant. And three, patients who are not transplant candidates and have no other options, as destination therapy.”
When employed as a bridge to recovery, a VAD is considered short term. In addition to aiding heart attack patients, it is also used in various conditions such as following open-heart surgery, in cases of viral or peripartum cardiomyopathy.
“In these cases, the heart can recover and become strong again,” Dr. Kohmoto said. “Short term is mostly days to weeks but can be up to several months."
Matching VADs to Patients
Physicians can choose from a range of devices to assist or replace heart function. With access to all the latest options, Froedtert & MCW cardiac specialists match patients to the assist device that will most benefit them.
If a short-term device is used, patients will stay in the hospital because they have a catheter inserted into either their neck or groin. As an example, for short-term support of the right ventricle, Froedtert & MCW specialists may use a VAD that connects an external pump to a neck cannula for input and output of blood. The device is about the size of an EKG machine.
When left side support is required, physicians may specify a percutaneous catheter-based system that incorporates a miniature, axial flow pump. The catheter is advanced into the aorta, across the aortic valve and into the left ventricle. A bedside controller about the size of a laptop computer provides power and manages all functions of the VAD.
“We always watch how many liters of blood per minute flow through these VADs, and then look at parameters including blood pressure, pulmonary artery pressure, cardiac output and urine output,” Dr. Kohmoto said.
The devices allow physicians to calibrate the performance to the patient by adjusting the revolutions per minute of the pump. They can dial in as much as 100% assistance, or as little as 10-20%, at which level the heart is likely strong enough to function on its own and the patient can be weaned from the device.
Patients who receive a VAD as destination therapy have a pump surgically and permanently implanted into their chests. With an external power supply or battery pack, they can return home and be mobile.
“These are patients who are not candidates for a heart transplant due to various health conditions,” said Nunzio Gaglianello, MD, medical director of mechanical circulatory support and MCW faculty member. “Patients with long-term VADs do very well. In fact, it’s not uncommon for us to see patients with VADs live 5-10 years if not longer.”
“We have also seen that some patients with VADs as destination therapy may have cardiac recovery to a point that the VAD can be removed. While uncommon today, advancing VAD technology and medications for heart failure have shown that even patients originally intended to live with a VAD for the remainder of their life may recover to a point where the VAD can be removed.”
Quick Response, Ongoing Care
Treating VAD patients requires extensive resources in both infrastructure and expertise. The Froedtert & MCW cardiac team offers the advantage of a group of specialists, including cardiac surgeons, heart failure cardiologists, cardiac anesthesiologists and critical care teams.
VADs can be implanted in either the operating room or the catheterization lab. In addition, Froedtert Hospital has a unique hybrid suite for performing both cardiac surgery and interventional cardiology procedures, where surgeons and cardiologists frequently work together.
“Often, these patients cannot wait until the next morning,” Dr. Kohmoto said. “We have to be able to do the procedure at any time otherwise the patient may not survive through the night. Although there are many variables, once the patient is in the hybrid room or cath lab and a device is chosen, we can complete most VAD procedures in under 30 minutes.”
The Froedtert & MCW cardiac team works in tandem with community physicians and hospitals that also perform VADs, providing essential post-procedure care.
“Certain types of devices can be initiated immediately at a local hospital when needed, with the patient then transported to us for more definitive treatment,” Dr. Kohmoto said. “Many patients benefit from this approach because their care management requires extensive resources, including the ICU, the expertise of a multidisciplinary team and a high nurse-to-patient ratio.”
The medical science of VADs is an evolving area, with smaller pumps, less invasive procedures and techniques that are very different from those of just three years ago. The Froedtert & MCW health network has made a strong institutional commitment to performing and advancing VAD procedures for patients.
“We’re aggressive in staying up to speed with the newest and most effective technology to ensure we can meet the needs of patients referred to our team,” Dr. Kohmoto said.
HeartMate 3™ Left Ventricular Assist Device (LVAD). Reproduced with permission of Abbott, © 2020. All rights reserved.
