This article appeared in the Spring 2009 issue of Cardiovascular Update.
World’s smallest assist device in trial at BWH
Cardiologists at Brigham and Women’s Hospital (BWH) are currently participating in the Protect II trial of Abiomed’s Impella 2.5, the world’s smallest ventricular assist device (VAD), for use in high-risk angioplasty.
In June 2008, the catheter-based heart pump device received FDA clearance for use as partial circulatory support for periods up to six hours, and it is currently used to support heart function during a stent procedure in very weak patients. Brigham and Women’s Hospital was the only site in New England to participate in Protect I, the original feasibility study to determine Impella 2.5’s impact on the outcomes among high risk patients.
This new, multi-center, randomized trial, which compares Impella 2.5 to the Intra Aortic Balloon Pump (IABP) in high-risk patients who require percutaneous coronary intervention, will determine if there is a clinical benefit to using the Impella device instead of the balloon pump.
“There are some patients who have severe problems with heart function or with blockages in the arteries and it is too risky to undergo open heart surgery, but they need to have treatment to improve blood flow,” says interventional cardiologist Laura Mauri, MD. “Impella is a way for patients to do coronary stenting and avoid the need for surgery.”
Significant advantages of this new device
Using a support device to aid these patients adds another level of safety because they are less prone to deterioration. “This is cardiac output that is compatible with life and the closest option available to a surgical ventricular device,” says interventional cardiologist Piotr Sobieszczyk, MD, of the Impella device. “It can be used in patients with or at high risk for heart failure.”
Its small size and ease of implementation present tremendous advantages to high risk patients, such as those with severe coronary heart disease. With blood flow of up to 2.5 liters per minute, it also provides impressive support and is easily tolerated by patients. “The Impella has a large application among patients undergoing high-risk coronary procedures,” says Dr. Sobieszczyk. “Its design enables it to be placed as quickly as the balloon, while providing more support than the balloon device.” The Impella sits in the left ventricle, and, while blood is still ejected by the patient’s heart, it is augmented through the pump.
Percutaneous devices also can be used in patients who have recently suffered myocardial infarction to support recovery of a “stunned” heart muscle. The use of Impella in these cases has been under investigation in Europe in the ISARSHOCK trial with what Dr. Sobieszczyk says are “promising results” and demonstrates more potential for the device. Dr. Mauri notes that BWH will be participating in similar randomized trials in the near future.
Improved surgically implanted VADs
Cardiac specialists at BWH also offer surgically implanted VADs that offer intermediate- to long-term support. According to Gregory S. Couper, MD, Surgical Director of the Circulatory Assist Program, emphasis is now on rotary blood pump assist devices like the HeartMate II, which received FDA approval as a bridge to transplantation in Spring 2008. The Carl J. and Ruth Shapiro Cardiovascular Center at BWH is currently a site for trials of the HeartMate II as destination therapy.
The HeartMate II is smaller, more portable, and provides continuous blood flow compared with the earlier generation HeartMate XVE, which was used by surgeons at BWH as a bridge to transplantation and as destination therapy. According to Michael M. Givertz, MD, Medical Director of the Heart Transplant and Circulatory Assist Program, the newer device is quieter, provides faster post-op recovery, and is more durable (expected to last up to five years).
Short-term devices provide “bridge to decision”
There has also been a substantial increase in the use of shortterm devices, both in the Catheterization Lab and in the operating room. “These devices allow us to buy time to ascertain whether the patient will be a transplant candidate or will recover,” says Dr. Couper.
- CardiacAssist Tandem Heart – a PVAD which can be used both in the catheterization lab or surgically implanted as a short-term solution to myocardial infarction or myocarditis and allows the patient either time to recover or transition to a long-term device;
Ongoing Cardiovascular Center trials
The Cardiovascular Center also is involved in trials assessing:
- SyncCardia Temporary Total Artificial Heart – a single device that replaces both ventricles and received FDA approval as a bridge to transplantation. A new driver provides patients with biventricular fully implantable support.
“Companies are focusing on smaller devices with better durability and fewer complications and when these devices work well, it’s amazing. We’re taking a patient who is dying and restoring normal heart functions,” says Dr. Givertz.
Dr. Givertz notes that, in particular, the left ventricular assist devices (LVADs) are being used with cardiac patients as a “bridge” to decision, “bridge” to transplantation and destination therapy. “LVADs enable many of these patients to live long enough to be transplant-eligible,” says Dr. Givertz.
Improved quality-of-life with VADs
VADs also provide patients with the ability to go home, which, as Dr. Givertz notes, vastly improves their quality of life. BWH facilitates this transition by enlisting a team of professionals — surgeons, physicians, nurse practitioners, nutritionists, social workers, clergy, palliative care specialists — to ensure that the home, the community, the patient’s caregivers, and the patient are equipped and prepared to be home. “It’s quite an amazing team of people that takes care of a patient,” notes Dr. Givertz.
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