A study published in the February issue of the Journal of American College of Cardiology cites favorable results in the use of Abiomed's (Danvers, Massachusetts) Impella 2.5 system in patients undergoing high-risk percutaneous coronary intervention (PCI).

The study shows results from the Protect I trial, and concludes that the system is "safe, easy to use and provides excellent hemodynamic support during high-risk PCI."

The PROTECT I trial enrolled 20 patients undergoing high-risk PCI at seven centers between July 2006 and April 2007. Eligible patients had left ventricular ejection fraction (EF) of less than 35% and were required to undergo PCI on either an unprotected left main coronary artery or the last patent coronary conduit.

Patients with recent ST-segment elevation myocardial infarction or cardiogenic shock were excluded. The primary safety end point was the incidence of major adverse cardiac events at 30 days. The primary efficacy end point was freedom from hemodynamic compromise during PCI (defined as a decrease in mean arterial pressure below 60 mm Hg for more than 10 minutes).

The Impella 2.5 device was implanted successfully in all patients. The mean duration of circulatory support was 1.7 ± 0.6 h (range: 0.4 h to 2.5 h). Mean pump flow during PCI was 2.2 ± 0.3 l/min. At 30 days, the incidence of major adverse cardiac events was 20% (two patients had a periprocedural myocardial infarction; two patients died at days 12 and 14).

There was no evidence of aortic valve injury, cardiac perforation, or limb ischemia. Two patients (10%) developed mild, transient hemolysis without clinical sequelae. None of the patients developed hemodynamic compromise during PCI.

"The advantage to having a small heart pump is that it is minimally invasive," said a company spokesperson via e-mail to Medical Device Daily. "Other LVADs require a sternotomy, or cracking of the chest, for implantation. Impella 2.5 is implanted percutaneously via the femoral artery and up through the aorta, hooking into the left ventricle. Impella increases the blood flow and oxygen supply to the heart, while decreasing demand, essentially reducing the workload on the heart by doing 30% of the work for pumping blood, with a pump that is 100th the size of the heart."

The study shows that the Impella provides hemodynamic support by directly unloading the left ventricle and reducing oxygen demand and the work on the heart, while increasing oxygen supply.

The device was initially developed in Aachen, Germany, by Impella CardioSystems (Aachen Germany). Abiomed acquired Impella CardioSystems in the spring of 2005 for $1.8 million in cash (Medical Device Daily, April 28, 2005).

The Impella device then received 510(k) clearance from the FDA in June 2008 for partial circulatory support for periods up to six hours.

Now approved in more than 40 countries, including in Europe under the CE mark, Impella 2.5 has been used to treat more than 1,700 patients worldwide and has been the subject of more than 50 peer-reviewed publications.

The company said that it also is conducting two U.S. pivotal studies comparing the Impella 2.5 to the IABP (Protect II for high-risk percutaneous coronary intervention, or PCI; and Recover II for acute myocardial infarction, AMI or heart attack).

There are an estimated 60,000 annual high-risk PCI patients and 100,000 AMI anterior infarct patients annually in the U.S.

Other companies developing similar devices include Ventracor (Chatswood, Australia) HeartWare (Framingham, Massachusetts/Sydney Australia) and Thoratec (Pleasanton, California).

Ventracor offers the VentraAssist, a VAD that operates on a hemodynamically-suspended titanium impeller. The VentraAssist has a CE mark, and is currently enrolling patients in a U.S. pivotal trial (MDD, Sept. 19, 2007).

HeartWare developed its HeartWare Left Ventricular Assist System (LVAS) at Washington Hospital Center (WHC; Washington), which marks the start of the company's U.S. bridge-to-transplant clinical trial. Steven Boyce, MD, surgical director of the heart failure program at WHC, performed the surgery. The pump is small enough to fit in the pericardial space adjacent to the heart.

Thoratec won an approvable recommendation with conditions from the circulatory systems advisory panel of the FDA late last year for the HeartMate II, the newest generation of the company's HeartMate LVAD (MDD, Dec. 4, 2007).

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