Published in UAB Insight, Spring 2008
New Option for Patients at High Risk
Patients with multivessel coronary artery disease and severe left ventricular dysfunction are at high risk for problems with percutaneous coronary intervention (PCI) and often are poor surgical candidates because of comorbidities. Individuals who have severe three-vessel coronary artery disease and decreased heart muscle function are at higher risk of morbidity and mortality during PCI compared with low-risk, hemodynamically stable patients. Prophylactic use of the intra-aortic balloon pump (IABP) during PCI provides limited circulatory support but requires residual cardiac function and stable cardiac rhythm. It is unlikely to completely reverse shock and restore normal hemodynamics in people with circulatory hemodynamic collapse.
The Impella Recover 2.5, a percutaneous ventricular unloading catheter device developed by Abiomed, addresses these limitations. “This device allows safe and effective PCI in a subset of patients with significant heart disease who are not candidates for surgery or who refuse surgery,” says UAB interventional cardiologist Raed A. M. Aqel, MD, who has placed several of the devices as part of an investigational study. “The device increases the odds of success,” he says.
In several trials investigators have used the Impella to treat acute myocardial infarction, cardiogenic shock, and low output syndrome with favorable outcomes and few adverse events. The device is a miniature pump inserted through the femoral artery that rotates to propel blood from the left ventricle (LV) into the ascending aorta, enabling immediate and sustained LV unloading and increased overall systemic cardiac output. While the IABP delivers an output of only 0.5 L/min, the Impella device can unload at a rate up to 2.5 L/min. The flow can be increased and decreased as needed.
In a 2007 study, researchers successfully implanted 109 patients with the Impella Recover 2.5 during high-risk PCI with no intraprocedural deaths and a low adverse event rate (J Am Coll Cardiol. 2007;49:54-60). By increasing overall cardiac output, the device allows interventional cardiologists more time for complex angioplasties and causes less patient discomfort than the IABP (Am J Cardio. 2006;97[7]:990-992). Unloading the left ventricle increases aortic and intracoronary pressure, hyperemic flow velocity and coronary flow velocity, and decreases microvascular resistance (Catheter Cardiovasc Interv. 2007;70[4]:532-537).
Protect II Study
Aqel is principal investigator for a multicenter trial underway at UAB comparing the Impella Recover 2.5 with IABP. Investigators plan to enroll 650 patients at 150 sites. “Impella may provide better stable hemodynamic support during procedures than the IABP, enabling patients with compromised ventricles to avoid adverse effects of transient ischemia and intraprocedural complications such as vessel dissection and thrombus formation with subsequent severe hypotension,” he says.
UAB is enrolling patients scheduled for nonemergent PCI of at least one de novo or restenotic lesion in a native coronary vessel or bypass graft. High-risk individuals are those with ejection fractions <30% to 35% with severe three vessel coronary artery disease and/or severe graft disease and at least one intervention on one or more coronary artery or the last patent coronary conduit. Also included is intervention on unprotected left main coronary artery disease. UAB has enrolled 17 participants, the largest number of any participating center in the country.
For more information:
Dr. Raed Aqel
1.800.UAB.MIST
mist@uabmc.edu