Impella CP to Impella 5.5 Uninterrupted Upgrade Using a Double Device Technique

Introduction

Although there are different types of mechanical circulatory devices available to enable hemodynamic support in patients with cardiogenic shock, the peripherally inserted percutaneous left ventricular assist device, Impella (Abiomed Inc., Danvers, Massachusetts, USA), is the only transaortic valvular device that provides circulatory support and directly unloads the left ventricle.1 Currently, two peripherally inserted trans-valvular microaxial pumps are available: the Impella CP and Impella 5.5.

The Impella CP can be placed rapidly in the catheterization laboratory in patients with refractory cardiogenic shock to correct hemodynamic disarrangement. However, there is a subset of patients that may need a higher level of support and will require an upgrade to the surgically implanted Impella 5.5 device. Traditionally, during the exchange, the Impella CP is turned off and retrieved out of the ventricle, and then the Impella 5.5 is inserted into position and started. This process takes time and can create hemodynamic instability due to the interruption of mechanical support. Ultimately, some patients require increasing doses of inotropic drugs and even additional support, such as veno-arterial extracorporeal membrane oxygenation (V-A ECMO).

We present a novel technique to be used in patients with minimal left ventricular reserve. For the first time, we detail how to exchange an Impella CP with an Impella 5.5 with uninterrupted support and no hemodynamic disarrangement.

Technique

The patient on Impella CP support is placed under general anesthesia and in the supine position on the operating table. An arterial line is placed opposite of the future Impella 5.5 insertion site. If not previously done, a central venous line and pulmonary artery catheter is placed. Transesophageal echocardiography is performed to evaluate the Impella CP position, ventricular function, and baseline mitral regurgitation.

An infraclavicular incision is performed, and the axillary artery is exposed. Activated clotting time is checked and must be greater than 200 seconds; heparin is given to achieve this goal. The conduit graft is sutured to the axillary artery and externalized followed by insertion of the J wire and pigtail catheter. This is done in a retrograde fashion from the graft, through the axillary artery, innominate and aorta, crossing the aortic valve, and into the left ventricle. The wire is switched to a.018 wire (Figure 1), and the Impella 5.5 is advanced under fluoroscopic guidance as previously described.2

F1Figure 1.:

Fluoroscopic imaging: the Impella CP is in place and the J wire coming from the axillary artery approach is within the left ventricular apex.

The double device technique enables continued support with the Impella CP as the aortic valve is crossed with the Impella 5.5 (Figure 2). After the Impella 5.5 is confirmed in the proper position and while both devices are in place, the wire is removed and the support is transferred from the Impella CP to the newly inserted one. Next, the Impella CP is paused, pulled out of the ventricle, and positioned at the descending aorta (Figure 3).

F2Figure 2.:

(A) The Impella CP is at the top, and the Impella 5.5 is at the bottom of the image. Both devices are with the inflow portion close to the left ventricular apex, whereas the patient is still supported with the Impella CP. (B) Echocardiogram long axis aortic view showing both Impellas within the left ventricle.

F3Figure 3.:

Fluoroscopic imaging: the Impella 5.5 is located with inflow in the left ventricle, while the Impella CP is pulled out of the left ventricle and is now parked in the descending thoracic aorta.

The procedure is finished by trimming the conduit, peeling the introductory sheath, and securing the Impella 5.5 device. Simultaneously, open removal of the Impella CP is done with the repair of the common femoral artery. At the end, both incisions are closed, and Doppler signals are obtained on the dorsalis pedis, posterior tibial, and ipsilateral radial artery.

Comment

The indication for switching from the Impella CP to the Impella 5.5 varies and includes patients who require prolonged support for which the exchange allows patient mobilization and avoids deconditioning.3 It is also indicated in patients with severe hemolysis to avoid pigment deposition and kidney failure. Finally, patients with a minimal ventricular reserve that require more flow to achieve adequate organ perfusion may need an exchange.4

Our institutional experience and others4 have identified that the traditional exchange process can significantly affect hemodynamics. To mitigate the hemodynamic disarrangement that can occur during Impella exchange, peripheral V-A ECMO may need to be deployed in patients with minimal left ventricular reserve function. Uninterrupted Impella support during the exchange avoids the need for high inotropic support and the use of V-A ECMO, which is expensive and increases the risk of complications.5

We conceived and applied a novel exchange technique that avoids hemodynamic disarrangement. Uninterrupted flow is provided by transitioning support from one device to the other, thus excluding the need for additional supportive measures. We found that crossing the aortic valve is easier when the Impella CP is in place.

Another consideration is the fact that the Impella CP has a pigtail at the tip, whereas the Impella 5.5 lacks one. In our opinion, this structural issue avoids entrapment during the exchange.

We propose the application of the double device exchange technique for Impella upgrading in those patients with cardiogenic shock despite full support with the Impella CP. Higher support through an Impella 5.5 is recommended. This easy and fast technique provides uninterrupted mechanical circulatory support with no hemodynamic disarrangement.

Acknowledgment

The authors thank Drs. Michelle Gehring and Jessica Moody for editorial support.

References 1. Meyns B, Dens J, Sergeant P, Herijgers P, Daenen W, Flameng W: Initial experiences with the Impella device in patients with cardiogenic shock - Impella support for cardiogenic shock. Thorac Cardiovasc Surg. 51: 312–317, 2003. 2. Salas De Armas IA, Patel MK, Patel JA, et al. Insertion of Impella 5.5 via the axillary artery graft under fluoroscopic guidance. Oper Tech Thorac Cardiovasc Surg. 2021. doi: 10.1053/j.optechstcvs.2021.05.002. 3. Esposito ML, Jablonski J, Kras A, Krasney S, Kapur NK: Maximum level of mobility with axillary deployment of the Impella 5.0 is associated with improved survival. Int J Artif Organs. 41: 236–239, 2018. 4. Bertoldi LF, Delmas C, Hunziker P, Pappalardo F: Escalation and de-escalation of mechanical circulatory support in cardiogenic shock. Eur Heart J Suppl. 23(suppl A): A35–A40, 2021. 5. Nakasato GR, Murakami BM, Batistão Gonçalves MA, Lopes JL, Lopes CT: Predictors of complications related to venoarterial extracorporeal membrane oxygenation in adults: a multicenter retrospective cohort study. Heart Lung. 49: 60–65, 2020.

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