Novel Method for Exchange of Impella Circulatory Assist Catheter: The "Trojan Horse" Technique

Abstract: Patients with an indwelling Impella may require escalation of hemodynamic support or exchange to another circulatory assistance platform. As such, preservation of vascular access is preferable in cases where anticoagulation cannot be discontinued or to facilitate exchange to an alternative catheter or closure device. Challenges exist in avoiding bleeding and loss of wire access in these situations. We describe a single-access “Trojan Horse” technique that minimizes bleeding while maintaining arterial access for rapid exchange of this percutaneous ventricular assist device. 

J INVASIVE CARDIOL 2017;29(7):250-252. Epub 2017 May 15.

Key words: ventricular assist devices, new technique, Impella, percutaneous 

Currently, the Impella (Abiomed) percutaneous ventricular assist catheter and repositioning sheath do not offer the ability to easily perform catheter exchange while maintaining wire position. An option is to withdraw the catheter to the common femoral artery and attempt to advance an 0.018˝ guidewire through the outflow cage (Figure 1), but this technique is limited due to substantial bleeding through the outflow cage, especially if balloon occlusion of the ipsilateral iliac artery has not been performed.¹ This technique threatens complete loss of access if the catheter were to be inadvertently pulled out of the arteriotomy while the wire is being advanced through the Impella catheter. Another option is dividing the Impella catheter and advancing a 14 Fr sheath with a 10 Fr sheath telescoped within.² While avoiding bleeding from the catheter and maintaining access, this technique is limited by the loss of wire position and the time involved with multiple sheath exchanges. We describe a rapid “Trojan Horse” technique of exchanging an Impella catheter for a 17 Fr veno-arterial extracorporeal membrane oxygenation (VA-ECMO) catheter with minimal blood loss while continuously maintaining arterial access.

Case Presentation

A 55-year-old woman presented in cardiogenic shock with myocardial infarction several days after symptom onset. An Impella CP catheter was placed for hemodynamic support. Over the course of several hours, the patient became anuric with advancing lactic acidosis. She was found to have right ventricular dysfunction with papillary muscle rupture and postinfarction ventricular septal rupture (Figures 2A, 2B). Operative repair was not immediately available. She was referred for placement of VA-ECMO. 

Procedure description. After adjusting the Impella CP to the P-2 setting, the catheter was withdrawn to the descending aorta. With manual pressure held on the arteriotomy, the repositioning sheath was withdrawn from the arteriotomy, keeping the catheter in the descending aorta. The catheter was disconnected from the console and punctured with a Cook needle (Cook Medical) at the 35 cm mark on the greater curvature with the hash marks, opposite from the dashed lines (Figure 3A). This location was selected because this portion of the catheter has a hollow lumen that is used for the standard fluid infusion when the motor is in operation, while the lesser curvature contains the electrical components necessary to operate the catheter and does not have a hollow lumen.

Next, a standard wire introducer was placed in the puncture site to facilitate advancement of a 0.018˝ guidewire with a radiopaque tip (Hi-Torque Steelcore; Abbott Vascular) (Figure 3B). The wire was advanced into the catheter until it abutted the outflow cage with a radiopaque tip to the proximal end of the catheter (Figure 3C). After removing the wire introducer, the Impella catheter was used to deliver the wire into the descending aorta by advancing the catheter to the aortic valve. When the radiopaque wire tip was visualized, the guidewire was unsheathed by withdrawing it and then advancing forward (Figure 4; Video 1). The wire was at this point outside of the Impella catheter, running parallel to it and out of the arteriotomy site. The catheter was then withdrawn and removed from the body while pressure was held on the arteriotomy, leaving behind the 0.018˝ guidewire. A standard 5 Fr long sheath was then advanced over the 0.018˝ wire used to exchange for an Amplatz Superstiff 0.035˝ guidewire (Boston Scientific). Soft tissue and arterial dilation was performed using a 16 Fr Coons dilator (Cook Medical) followed by 17 Fr arterial cannula placement. After placement of the venous cannula, VA-ECMO was initiated without incident and the patient returned to the intensive care unit while surgical planning continued. This “Trojan Horse” technique is outlined in Table 1.

Later, the patient underwent aneurysm resection of the inferior wall of the left ventricle and repair of the ventricular septal rupture with bovine pericardial patch and mitral valve replacement with 27 mm St. Jude tissue valve (St. Jude Medical). Her postoperative course was complicated by renal failure, bilateral ventilator associated pneumonia, and Clostridia difficile infection. On postoperative day 10, the patient expired after her hemodynamic status deteriorated with refractory shock; dehiscence of the repair was identified by transesophageal echocardiography and right heart catheterization.

Discussion

Transporting a hidden asset behind enemy lines is a form of subterfuge utilized since ancient times. This modern adaptation of a Trojan Horse allows preservation of arterial access and wire position with minimal manipulation by transporting and unsheathing a guidewire hidden within the central lumen of the Impella. This technique is valuable in cases where anticoagulation cannot be discontinued and to facilitate exchange to an alternate catheter or a closure device. The Trojan Horse technique simplifies the exchange, eliminates the need for a contralateral access for hemostatic balloon occlusion, and minimizes the risk of loss of complete vascular access, as occurs when a wire is advanced through the Impella outflow (Figure 1). Puncturing at the 35 cm mark serves as a midway point, minimizing the risk of losing access and allowing enough distance to advance both the wire and the catheter back into the aorta (Figures 2A and 2C). 

Conclusion

Rapid exchange of circulatory support devices is critical in patients presenting with cardiogenic shock, as highlighted by this case where the patient ultimately succumbed to mechanical complications and infection. The Trojan Horse technique is a valuable addition to the armamentarium of methods available to rapidly treat patients in shock. 

References

1.    Mathur M, Hira RS, Smith BM, Lombardi WL, McCabe JM. Fully percutaneous technique for transaxillary implantation of the Impella CP. JACC Cardiovasc Interv. 2016;9:1196-1198. 

2.    Kim MS, Clegg S, Messenger JC. Removal of Impella 2.5 while maintaining vascular access: a solution to a vascular quandary. Catheter Cardiovasc Interv. 2014;83:223-225. 

From the ¹Division of Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; and ²Baptist Hospital, Louisville, Kentucky.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Pinto reports personal fees from Medtronic, The Medicines Company, and Medicure. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted March 21, 2017 and accepted March 29, 2017.

Address for correspondence: Duane S. Pinto, MD, MPH, Division of Cardiology, Interventional Section, Beth Israel Deaconess Medical Center, 185 Pilgrim Road, Boston, MA 02115. Email: dpinto@bidmc.harvard.edu