Wireless Insertion of Abiomed Impella 2.5

New percutaneous left ventricular assist support technology has created new hope for the patient population presenting with acute coronary syndrome (ACS) and cardiogenic shock as well as in need of high-risk percutaneous coronary intervention (HR-PCI). Earlier systems required longer preparation time, limiting some systems in emergent care. Rapid preparation systems and modifications have improved the readiness of Impella 2.5 catheter (Abiomed, Inc., Danvers, MA) for emergency use. We describe the use of a new technique of “wireless” insertion of the Impella 2.5 system in an elective HR-PCI patient. Case Report Patient is a 64-year-old male with severe ischemic cardiomyopathy with an ejection fraction of 30% and Canadian Class III angina pectoris, as well as severe left internal carotid artery (LICA) disease. Patient underwent LICA stenting successfully, with embolic protection. His coronary angiography revealed a 90% left circumflex (LCX) proximal stenosis and 90% in-stent restenosis (ISR) of the obtuse marginal (OM). The patient, in the past, had prior LCX/OM PCI at an outside institution and had repeat PCI several months prior to this admission. At that time, LCX PCI was successful; however, the OM ostial stenosis could not be crossed with a wire. Due to the complexity of PCI, prophylactic use of hemodynamic support was felt to be necessary due to a likely prolonged procedure, as well as the potential for acute closure. Rather than the standard wired technique, we chose to use the “wireless” insertion of the Impella 2.5. This technique does not require the use of diagnostic catheter placement in left ventricle to place a wire and then back loading of the Impella device. In our opinion, it is simpler and efficient. After the device is inserted through the sheath, it is advanced gently under fluoroscopy to engage the aortic valve. Rotating the catheter while pulling back slightly allowed passage into the left ventricle (LV) after two brief attempts. The inlet was positioned so that it was approximately 4cm from the aortic valve. The Impella was activated and advanced through the power setting until a flow of 2.3L/min was obtained. The PCI was then carried out with excellent support delivered by the Impella. Complete revascularization of the proximal LCX as well as the OM branch was performed without any hypotension or ischemic event. Discussion This case demonstrated the simplicity and quick insertion of the Impella device, which may be advantageous in urgent situations when time is of the essence. Data from the USpella registry was recently presented at EuroPCR.(1) Although the most common indication for Impella support remained HR-PCI, both elective and urgent, 17% of the USpella registry patients were supported for acute MI cardiogenic shock. By eliminating the use of the wire for insertion, it is possible to expedite insertion of the Impella device to better respond in an acute care situation, and ultimately provide hemodynamic support to facilitate a more complete revascularization. Kirschbaume et al (2) found that completeness of revascularization was positively related to improvement in ejection fraction at 6 months post PCI. Patients who had an incomplete or failed revascularization had no such improvement. Initiation of mechanical support prior to PCI was also found to be an independent predictor of survival.(3) The Impella 2.5 is an endovascular microaxial blood pump that provides up to 2.5 liters/min of forward cardiac flow. The pump is inserted percutaneously via the femoral artery and into the left ventricle. The pump delivers blood from the inlet area, through the cannula and to the outlet area in the ascending aorta. The standard technique for placement has normally been accomplished by placing a diagnostic catheter into the left ventricle after crossing the aortic valve. A 0.018" guidewire is advanced to the apex, and using a monorail technique, the Impella 2.5 is advanced into the left ventricle, the wire is removed, and pumping is commenced. The new “wireless” technique has been used as an alternative to the standard technique and may offer the advantage of eliminating several steps from the traditional method. The improvements to the systems (The Impella 2.5 Next Generation System) include a nitinol spine, which significantly improves robustness with respect to kinking. The use of the wireless technique should be limited to the Next Gen (product number 004672) system, since kinking of the purge system lumen in earlier versions of the catheter could result. The operator should confirm with the device manufacturer to make certain that the catheter in use is a next-generation device. The technique is simple and straightforward, but should be used only after one is fully familiar and experienced with the wired method. First, a 13 French (Fr) introducer sheath is placed in the common femoral artery. Heparin is administered to move the activated clotting time (ACT) to >250 seconds and then the dilator is removed from the 13 Fr sheath. The pigtail at the end of the Impella is straightened by hand, and advanced through the sheath and through the hemostatic valve. Small steps or “bites” are taken with the initial advance until the Impella cannula and motor assembly is advanced into the artery and is clear of the sheath. The device is tracked fluoroscopically as it is moved up into the descending aorta, maintaining the pigtail on the medial aspect of the aorta closer to the spine. When the aortic valve is reached, the pigtail is brought down against the medial cusp of the valve and continued until the catheter begins to prolapse. Pulling the catheter back slightly while turning the catheter clockwise should allow the catheter to “pop” across the valve. If the catheter fails to gain entry to the left ventricle, the catheter is pulled back, rotated 45 degrees and the process is repeated. There are several important points to be made with respect to this wireless technique. First, the catheter must be visualized at all times. Excessive force should not be applied to the device, particularly in the region of the aortic valve. The operator should also avoid excessive twisting of the device more than 360 degrees, since doing so will result in tangling of the pump cable and purge tubing. The filter set pressure reservoir should be clipped to the blue pump cable and is rotated with the red pump plug, since this will ensure that the torsional loads do not get transferred to the filter set and cause a kink. It is beneficial to review the left ventriculogram and subsequent filling of aorta to determine suitability for wireless insertion. If the attempt at wireless insertion does not yield entrance into the left ventricle, consideration should be given to reverting to the wired method of insertion. The catheter should be withdrawn, rinsed with heparinized saline, and placed into a clean basin to avoid any contact with loose fibers, which can interfere with the operation of the Impella. Patients with known or suspected aortoiliac peripheral vascular disease and torturosity are not prime candidates for the wireless method, and should be approached with the standard technique from the outset. Similarly, patients with a diseased aortic valve should be approached with standard technique. The operator should refer to the IFU of the device for specific precautions and contraindications. Conclusion Use of this wireless technique has proven to have merit in our practice. I personally have performed approximately ten wireless insertions without any complications. There is no additional cost associated with this technique. Patients who present with emergent clinical problems requiring hemodynamic support may benefit from this technique. Practitioners should be familiar with the standard insertion technique prior to using the wireless technique. Practitioners should be fully familiar with IFU instructions, precautions and contraindications. Dr. Dave can be contacted at rdintervention@yahoo.com Disclosure: Dr. Dave reports he has received an honorarium as a speaker for Abiomed, Inc. This article received double-blind peer review from members of the Cath Lab Digest editorial board. References 1. O’Neill W. USpella Registry Results Presented at: EuroPCR; May 25-28, 2010; Paris, France. 2. Kirschbaum SW, Springeling T, Boersma E, et al. Complete percutaneous revascularization for multivessel disease in patients with impaired left ventricular function: pre- and post-procedural evaluation by cardiac magnetic resonance imaging. JACC Cardiovasc Interv 2010 Apr; 3(4): 392-400. 3. Abdel-Wahab M, Saad M, Kynast J, et al. Comparison of hospital mortality with intra-aortic balloon counterpulsation insertion before versus after primary percutaneous coronary intervention for cardiogenic shock complicating acute myocardial infarction. Am J Cardiol 2010; 105(7): 967-971.

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