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Miniature heart pump aids blood flow after surgery, cardiogenic shock
Positive outcomes and increased hemodynamic stability found with Impella Recovery Systems.
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The Impella systems, investigational systems of ventricular heart pumps currently available in Europe, may be viable alternatives to the use of common intraaortic balloon pumps and ventricular assist devices in patients undergoing percutaneous coronary intervention or other high-risk procedures.
Abiomed’s Impella 2.5 heart pump and its more powerful counterpart, the Impella 5.0, are not yet commercially available in the United States; the Impella 2.5 is pending FDA approval and could be commercially available by mid-2008.
Miniaturized pumps
“For the last 15 years, doctors have treated revascularization and have treated the electrical signal that drives the heart, but they have been unable to treat the pumping mechanism of the heart,” Michael Minogue, chairman, president and CEO of Abiomed Inc., told Cardiology Today. “Impella has the ability to pump blood by pulling the blood directly from the left ventricle and propelling it with forward flow motion through the coronaries as well as to the brain and kidneys. You are able to introduce this pump through the femoral artery so that a sternotomy is not required.”
Preliminary study results for the Impella 2.5 device suggested that it may facilitate left ventricular support. Once activated, the Impella pump, barely the size of a pencil eraser and weighing about 8 grams, works to lighten the workload on the heart and to increase systolic and diastolic BP as well.
The Impella 2.5 consists of a miniaturized electrical rotary pump delivered by a specialized catheter, which carries the pump over a guide wire through the femoral and left peripheral arteries into the left ventricle. One end contains an inflow cannula. Once navigated into position through the aortic valve, the Impella can aspirate between 2.5 L and 5.0 L per minute from the left ventricle into the ascending aorta. A pressure sensor within the device continuously monitors pressure differences between inflow and outflow.
The Impella pumps have been indicated for temporary use and are usually implanted during surgery or immediately afterward as the heart regains its strength. The Impella 2.5, however, has also been known to support hemodynamics without problems for up to five days. The Impella 5.0, although still investigational, has been observed functioning for as long as 10 days.
Emerging studies and data
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Source: Abiomed Inc. |
Study results from the Left Ventricular Assist Device Versus Intraaortic Balloon Counterpulsation for Patients with Cardiogenic Shock by MI (ISAR-SHOCK) trial suggested that the Impella 2.5 device provided better hemodynamic support than the intraaortic balloon pump in patients with acute MI and that the Impella 2.5 device is feasible for use in 90% of patients presenting with acute MI.
Some study results have suggested that patients who receive the Impella 2.5 pump tend to show improvements in hemodynamic balance, adverse events and have higher rates of recovery. According to results from the Prospective Feasibility Trial Investigating the Use of Impella Recover LP 2.5 System in Patients Undergoing High Risk PCI (PROTECT I) study, PCI procedures where Impella is used had a 95% success rate. Major adverse cardiac events at 30 days included two deaths (10%) and two MIs (10%); bleeding requiring transfusion (5%) as well as hemolysis rates (10%) were considered minimal. The researchers also found no incidences of valvular injury or aortic insufficiency.
The Impella 5.0 pump is currently in the late stages of the Impella RECOVER LP/LD 5.0 Support System: A Clinical Safety & Feasibility Study (RECOVER I), scheduled to end in April. There remains, however, a lack of outcomes data for both Impella devices. Researchers are conducting a second PROTECT trial to evaluate outcomes after implantation of the Impella device.
“There really are little prospective scientific data on these kinds of high-risk patients who receive Impella,” William O’Neill, MD, professor of medicine, Leonard M. Miller School of Medicine at the University of Miami, said in a presentation at the Transcatheter Cardiovascular Therapies 2007 meeting in Washington. “With the PROTECT II trial, we are going to be carefully collecting outcomes data for these patients so that we will know what the outcomes for the balloon pump and the Impella devices are, and this will give us a great deal of information on how this procedure is being performed in the United States right now.”
Impella 5.0 in the U.S.
Although use and sale of the Impella 2.5 and 5.0 are not yet approved in the United States, there are patients in the United States who have been implanted with the investigational Impella 5.0. At the University of Maryland Medical Center, three patients have been implanted with the device in an effort to expand a 20-patient pilot study.
“We have patients right now who have been on it beyond a seven-day term, and we are trying to bridge to transplant,” Bartley Griffith, MD, chief of the division of cardiac surgery at the University of Maryland Medical Center, Baltimore, told Cardiology Today. “It is a simple, well-functioning device, and it may be where the future of ventricular support systems is headed. It is minimally invasive, has a high level of potential effectiveness, and when you pair it up with the Impella 2.5 system, it makes quite a nice family.”
According to a press release, the first patient implanted with the Impella 5.0 at the University of Maryland presented a heart functioning at about 20% of normal function. The patient had a cardiac index of 1.7. Two days after implantation with the Impella 5.0, the researchers wrote that the patient’s cardiac index had jumped to 3.4 without the aid of medication and that the heart had demonstrated increased and sustained strength. The researchers took this as a promising sign.
“The device can be implanted directly through an open chest as part of a procedure to replace a valve or during a coronary bypass, and it can also be delivered through the groin,” Griffith said. “There is a trade-off; we can now get 5 L of flow, but it requires more surgery to get the Impella 5.0 device in there. None of those things, though, are really difficult for the average heart surgeon.” – by Eric Raible
For more information:
- For more information on the Impella system, visit www.abiomed.com/products/impella.
- O’Neill W, Civitello A, Collins M, et al. A prospective feasibility trial investigating the use of the Impella Recover LP 2.5 system in high-risk PCI patients. #130. Presented at: the Transcatheter Cardiovascular Therapeutics meeting; Oct. 10-15, 2007; Washington.
- Lam KY, Sjauw KD, Muelen J, et al. A combined surgical and percutaneous approach through the axillary artery to introduce the Impella Recover 5.0 LP for short-term circulatory support. #203. Presented at: the Transcatheter Cardiovascular Therapeutics meeting; Oct. 10-15, 2007; Washington.