Impella CP Dislodgment, Swap, or Removal: Current Practices

Abstract

The Impella CP (ICP) catheter (Abiomed) offers hemodynamic superiority over the intra-aortic balloon pump. However, device-specific issues are occasionally encountered, especially when long-term mechanical circulatory support (MCS) is required. These include ICP dislodgment, ICP mechanical failure, and the need to remove the ICP while maintaining arterial access to either insert a new MCS device or to perform suture-based arteriotomy site closure. We offer a case in which ICP-based MCS involved ICP distal dislodgment, kinking of the ICP catheter, and removal of the device in a coagulopathic and thrombocytopenic patient. The literature regarding potential solutions to these problems is reviewed. Future ICP design is likely to reduce the frequency and complexity of such events and facilitate the management of these scenarios. This is the first report of a novel method to address ICP kinking dislodgment that did not respond to conventional repositioning maneuvers.

There is considerable increase in the use of the Impella CP catheter (ICP; Abiomed) for mechanical circulatory support (MCS) in cases of cardiogenic shock (CS) or complex percutaneous coronary intervention (PCI). We report a case of ICP dislodgment that required device repositioning and subsequent device removal in a patient with severe thrombocytopenia and coagulopathy. We discuss potential solutions to address the following management issues: (1) ICP catheter kinking dislodgment into the ascending aorta; and (2) the need to remove the ICP catheter while securing arterial access to the arteriotomy site.

Case Report

A 63-year-old male with no previous cardiac history was found unresponsive and pulseless by his neighbor, who initiated chest compressions and contacted emergency medical services (EMS). The patient’s “down time” was uncertain. EMS found him in ventricular fibrillation (VF); after cardiopulmonary resuscitation (CPR), the patient had return of spontaneous circulation. On arrival to the emergency department, echocardiography revealed severe left ventricular dysfunction and ejection fraction of 10%, with clear wall-motion abnormalities most pronounced in the left anterior descending (LAD) artery territory. The patient was taken to the cardiac catheterization laboratory, where transradial coronary angiography revealed discrete single-vessel coronary artery disease (95% stenosis of the proximal LAD), which was treated with 2.75 × 12 mm Synergy drug-eluting stent (Boston Scientific), resulting in TIMI 3 flow. While the patient was initially stable, he deteriorated hemodynamically over the next few hours and was hypotensive on high doses of norepinephrine. He failed to oxygenate on 100% oxygen and suffered from countless events of ventricular fibrillation. The patient also developed recurrent symptomatic episodes of bradycardia and acute anuric renal failure. He was taken back to the cardiac catheterization laboratory for insertion of an ICP, a temporary pacing wire, and a pulmonary artery catheter. These tasks were accomplished uneventfully, and the patient returned to the coronary care unit for observation. After a few hours, it appeared that the ICP distal tip migrated into the ascending aorta. This was confirmed by ICP hemodynamics, echocardiography, and chest x-ray. The cardiology team attempted ICP repositioning at bedside using echocardiographic and fluoroscopic guidance; however, the tip of the ICP catheter was kinked and did not allow advancement of the catheter under fluoroscopic guidance into the left ventricle. The patient was brought back to the cardiac catheterization laboratory.

Under full heparinization, the left radial artery was accessed with a 6 Fr radial sheath that was exchanged over a wire to a 70 cm × 6 Fr sheath. A 6 Fr Judkins right 4 guiding catheter was advanced over a 0.035˝ wire into the aortic arch. A 35 mm Amplatz GooseNeck snare (ev3) was advanced through the hemostatic Y-adapter and the guiding catheter to the aortic arch and captured the tip of the ICP device (the ICP pigtail) and pulled the ICP distal tip into the left subclavian artery to unfold the device (Figure 1). After unfolding the ICP tip, we could still not advance the ICP into the left ventricle. At that point, we elected to use the guiding catheter to lead the pigtail into the left ventricle – initially into the ascending aorta (Figure 2) and then into the left ventricle (Figure 3). Finally, the snare was released, the ICP maintained its position in the left ventricle (Figure 4), and full MCS was resumed.

FIGURE 1.

Attempt to unkink the Impella CP catheter by snaring its tip and pulling it toward the left subclavian artery. After unkinking, we could not advance the catheter into the left ventricle.

FIGURE 2.

The resnared Impella CP tip is dragged by the snare connected to the Judkins Right 4 (6 Fr) guiding catheter into the ascending aorta.

FIGURE 3.

The resnared Impella CP tip is dragged by the snare connected to the JR4 guiding catheter into the left ventricle.

FIGURE 4.

The Impella CP is released in the left ventricle in adequate position and good function.

A day after repositioning the ICP and resuming MCS, the patient’s hemodynamics improved dramatically, and his left ventricular ejection fraction normalized. He remained in acute oliguric renal failure and developed profound anemia, thrombocytopenia, and coagulopathy. The patient was typed and crossed for replacement blood products and received a transfusion of packed cells, platelets, and fresh-frozen plasma. We elected to remove the ICP in the cardiac catheterization laboratory. After withdrawing the ICP catheter into the abdominal aorta, protamine was given to reverse anticoagulation. In view of the design of the ICP repositioning sheath, we used the previously described Trojan-Horse method,¹ followed by a double Proglide (Abbott) closure of the arteriotomy site. In view of the thrombocytopenia and coagulopathy, we elected to use adjunctive contralateral wiring from the left femoral artery and imaging of the arteriotomy site after closure (Figure 5).

FIGURE 5.

Contralateral injection of the arteriotomy site (AS) closure with digital subtraction using 1 mL of contrast.

Discussion

This case report describes the following management issues occurring in a single patient requiring prolonged MCS with ICP: (1) distal dislodgment; (2) kinking of the distal tip of the ICP; and (3) need for ICP catheter removal while maintaining arterial access to allow suture-based arteriotomy site closure or to use the arterial access for alternative or similar MCS device.

It appears that these ICP-related issues are not exceedingly rare, especially when prolonged MCS is required; however, neither the literature nor the industry can provide accurate estimates of the incidence. As in most cases, there was no apparent cause for catheter displacement; however, ICP dislodgment during CPR,² cardioversion, defibrillation, patient movement, and even with no activity at all has been described. Similarly, device failure,³ hemolysis, thrombocytopenia, bleeding around the access site, and vascular complications during sustained mechanical circulatory support are not negligible, even with the lower-flow smaller sheath size of the ICP 2.5.⁴

Preparing for prolonged MCS.

The Abiomed package insert suggests that for prolonged MCS, the peel-away 14 Fr sheath (13 or 25 cm length) should be removed and a graded reposition sheath (9 Fr × 2 cm tapered tip with 15 Fr × 6 cm trunk) not equipped with side-port should be advanced. The current sheath design does not allow reinsertion of a wire into the arteriotomy site during device removal. Preclosure with 1–2 Proglides can be done; however, concern about suture sterility emerges and hence this strategy is not recommended by the manufacturer and does not allow convenient repeat access to the arteriotomy site.

Abiomed redesigned a more refined graded repositioning sheath (with a 9 Fr × 2 cm tapered tip and a 15 Fr × 10 cm trunk) that is currently under limited release (Figure 6). This new sheath design harbors a wire side-port compatible with 0.035˝ wires. This design simplifies ICP removal while maintaining arterial access to allow reinsertion of a large-bore sheath (≥14 Fr) or late suture-based arteriotomy closure.

FIGURE 6.

The futuristic Impella CP reposition sheath with side-port (SP) allowing 0.035˝ wire access.

There are at least two potential solutions to mitigate this problem when subjecting patients to prolonged MCS:

1. Use of a 14 Fr non-ICP sheath, such as the 14 Fr × 13 cm Cook sheath (Cook Medical) instead of the ICP peel-off sheath or the sliding tapered-tip ICP sheath. Ideally, the shortest possible sheath should be used unless there is extreme vessel calcification or tortuosity. Using a conventional sheath will allow closure of the arteriotomy site post procedure while applying external manual pressure on the arteriotomy site. The advantage of the 14 Fr commercial sheath is that the ICP catheter can be removed or replaced entirely through the sheath in case of mechanical failure or device dislodgment. The disadvantage is that the larger external distal diameter and longer sheath is more likely to be occlusive to the downstream arterial circulation.

2. Use of an arteriotomy site 0.018˝ parallel wire. After imaging the arteriotomy site, two wires are advanced via 5–6 Fr femoral sheath into the iliofemoral system toward the aorta. The ICP stiff, J-tip, 0.035˝ wire (or any other 0.035˝ stiff wire) and a 45 cm, 0.018˝ wire can be obtained from either a micropuncture kit or a radial sheath kit. The ICP peel-away sheath is advanced only over the 0.035˝ wire, while the 0.018˝ buddy-wire external tip is covered by the dilator of a 5 Fr micropuncture kit and is secured by a capped rotated stopcock (Figure 7) that is secured to the skin by a suture. In case the ICP needs to be removed or exchanged, it is simply removed with its ICP sheath while applying manual pressure, while the 0.018˝ buddy wire allows the advancement of a 6 Fr radial or femoral sheath under manual pressure exchange of the 0.018˝ wire to a 0.035˝ wire, which will allow insertion of a 14 Fr sheath or arteriotomy-site closure with 1–2 Proglides.

FIGURE 7.

The dilator of the Merit micropuncture kit harbors the 0.018˝ buddy wire to allow late closure of the arteriotomy site.

Removal of the ICP without the above advance preparations.

The literature describes three major principal methodologies to remove an ICP catheter while maintaining arterial access (detailed in Table 1). Briefly, the first is the “Trojan-Horse” method. The second method is various iterations of cutting the ICP catheter at the 100 cm mark, removal of the repositional sheath, and using the severed ICP catheter to advance a longer sheath 9 Fr telescoped within a shorter 11 Fr⁵ or 12 Fr⁶ sheath, or a 10 Fr sheath telescoped within a 14 Fr sheath,⁷ or a distally severed ICP 14 Fr peel-away sheath.⁸ The third method is pulling the ICP back, exposing the device blood outlet area, and advancing a 0.018˝, 190 cm wire from the outlet orifice into the inlet orifice and up into the aorta to maintain access while removing the ICP catheter. A fourth potential solution is snaring the tip of the ICP catheter tip from the contralateral femoral, withdrawing the ICP catheter, and externalizing the snare and snare catheter as a rail to maintain femoral arteriotomy patency.

Table 1.

Methods to remove the Impella CP (ICP) catheter while maintaining arterial access after a graded repositional sheath has been advanced.

The “Trojan-Horse” method

Turn ICP off and retract ICP to the 35 cm mark; withdraw repositional sheath and apply manual pressure on the arteriotomy site

Puncture ICP catheter on the 35 cm mark with a 21 G needle (on greater curvature opposite to the dashed line) and advance 0.018″ wire forward as far as it would go and remove 21 G needle

Advance the ICP catheter harboring the 0.018″ wire to the aortic arch

Pull the 0.018″ wire from within the ICP catheter and advance the exposed wire

Remove the ICP catheter while maintaining the 0.018″ wire across the arteriotomy

Advance a 6 Fr dilator over the 0.018″ wire and exchange the 0.018″ wire to a stiff 0.035″ wire to support the insertion of a 14 Fr sheath or close the arteriotomy site using 1–2 Proglides

Drawback: advancing semisterile ICP shaft into the arteriotomy site

Cutting ICP device at 100 cm mark and advancing a “telescoped sheath in sheath” over the ICP catheter

Turn ICP off and retract to the 80 cm marker; cut the ICP at 100 cm mark

Insert a 9 Fr sheath and dilator within a shorter 12 Fr or 11 Fr sheath (without dilator) and remove the dilator

Remove the ICP repositional sheath while applying manual pressure on the arteriotomy site

Advance the 9 Fr/12 Fr telescoped sheath over the ICP shaft

Remove the 9 Fr inner sheath and introduce 0.035″ stiff wire via the 12 Fr sheath into the thoracic aorta; remove the 12 Fr sheath and the ICP while maintaining wire position and arteriotomy site pressure

Insert a new 14 Fr sheath or close the arteriotomy site with 1–2 Proglides

Drawback: advancing a sheath over semisterile ICP shaft

Advancing a 0.018″ wire through the ICP

Turn ICP off and pull distal segment to the common femoral artery

Remove the repositional sheath and apply manual pressure on the arteriotomy site

Retract ICP until outflow outlet is exposed and advance 0.018″ 190 cm wire through the outlet to the thoracic aorta

Remove the ICP and advance 5 Fr dilator over the 0.018″ wire and exchange wire to 0.035″ stiff wire

Remove the dilator and advance a 14 Fr sheath over the stiff 0.035″ wire or close the arteriotomy site with 1–2 Proglides

Drawback: relatively short wiring track

Snaring the ICP catheter pigtail from the contralateral groin

Access contralateral femoral artery with 6 Fr sheath and advance 35 mm Amplatz Goose Neck snare kit through the sheath to the aortic bifurcation

Retract the ICP to the aortic bifurcation and snare the tip of the ICP pigtail; withdraw the ICP, reposition the sheath and subsequently the IPC while flossing the arteriotomy site

After externalizing the snare, advance the snare catheter over the snare; insert a 0.035″ wire stiff wire via the externalized snare catheter and externalize it to through contralateral sheath

Withdraw the snare catheter, insert a 14 Fr short sheath over the stiff 0.035″ wire, or close the arteriotomy with 1–2 Proglides

Drawbacks: (1) additional arterial access needed; (2) risk of shearing the ICP or losing grip; (3) cost of snare

Contralateral or ipsilateral wiring of the arteriotomy site prior to arteriotomy-site closure is optional to allow “dry seal” in the former (by using an occlusive balloon inflation) and to enable adequate imaging and treatment of arteriotomy-site complications.

Repositioning of the dislodged ICP catheter.

Unkinking or repositioning an ICP catheter is described here for the first time in the medical literature using a snare within a guiding catheter from the left radial approach. Previous reports of ICP kinking⁸ dislodgment were treated with ICP removal and insertion of a new Impella⁸ or another MCS.⁶ Since the cost of a second ICP is prohibitive and because removal of an ICP via the ICP tapered tip repositioning sheath is not without issues, the interventionist should make every effort to unfold or unkink and reposition the ICP device, assuming that MCR support is still needed and device functionality can be restored.

Conclusion

Dislodgment and need to remove an ICP while maintaining arterial access are events than can occur during prolonged MCS using the ICP. While the latter is being addressed by redesigned ICP repositioning sheaths, it is beneficial to acquire the knowledge and skills to mitigate or address these events.