Equipment loss and entrapment

27.1.3.1

Location of the lost stent

The location where the stent is lost determines the subsequent steps. If a stent is lost in a coronary artery it should be either retrieved or deployed/crushed. If a stent is lost in a noncritical location in the peripheral circulation (such as the lower extremity or pelvic vessels), it can often be left in place without attempting retrieval .

Occasionally, the lost stents may be difficult to visualize, especially thin strut stents in obese patients with calcified or previously stented coronary arteries. In such cases, intravascular ultrasonography may facilitate localization of the stent .

27.1.3.2

Retrieval needed/desired?

A lost stent does NOT always need to be retrieved. If the stent is lost in a noncritical location in the coronary artery, stent deployment (if wire position is maintained through the stent) or stent crushing (if wire position through the stent has been lost) can be a faster and safer approach. Similarly, if the stent is lost in a noncritical location of the peripheral circulation (such as the lower extremities), the risks of retrieval attempts often outweigh any potential benefit . Conversely, if the lost stent is located within a critical coronary artery (such as left main or major bifurcation) or peripheral artery (such as cerebral or renal arteries) location, retrieval is required.

27.1.3.3

Wire position maintained?

Maintaining wire position through the lost stent can greatly facilitate retrieval attempts (by using the small-balloon technique), and also allows for easier deployment if selected. If wire position is lost it is often impossible to rewire the lost stent, limiting retrieval options to snares or the “guidewire twirling” technique. Similarly loss of wire position does not allow deployment, making crushing the only option if retrieval is not needed or desired.

27.1.3.4

Small-balloon technique ( Fig. 27.3 )

The small-balloon technique can be used when a stent is dislodged from its delivery balloon but guidewire access is maintained through the lost stent. A small balloon is advanced through the stent, inflated distal to the stent, and then withdrawn together with the lost stent.

If the stent is not significantly deformed and the guide catheter is large, the balloon and the stent can be retrieved inside the guide catheter and removed. Often, however, the stent is too deformed to be withdrawn inside the guide catheter: in such cases the inflated balloon, lost stent, and the guide catheter are all removed together from the body ( PCI Manual Online case 10 ). It may be difficulty to advance the balloon through the stent, possibly pushing the stent more distally in the vessel. If the balloon is partially advanced through the stent, it can sometimes be inflated in the proximal-mid part of the lost stent, followed by removal of the entire system.

27.1.3.5

Snares

Snaring is an effective technique for retrieving lost or entrapped equipment. Available snares are discussed in Section 30.18.5 .

27.1.3.5.1

Stents lost in the coronary circulation ( Fig. 27.4 )

Once a loop snare is positioned around the stent to be snared, the snare wire is held still and the snare catheter advanced forward until the lasso loop secures the lost stent, followed by withdrawal of the assembly into the guide catheter.

For retrieval of stents lost in the coronary circulation the Micro-Elite snare (Vascular Solutions) (which is 0.014 in. in diameter, has loop sizes of 2, 4, or 7 mm, is 180 cm in length and does not require a delivery catheter) or the 2 mm or 4 mm En Snare (Merit Medical) are commonly utilized. An example of lost stent snaring from the coronary circulation is shown in Fig. 27.5 .

27.1.3.6

Guidewire “twirling” ( Fig. 27.6 )

In this technique, two or more 0.014 in. guidewires are advanced through or around the lost stent, and rotated several times to entangle their distal ends. The guidewires are then withdrawn often bringing the lost stent with them.

27.1.3.7

Reassess need for retrieval

If attempts to retrieve a stent lost in the coronary circulation fail, the need for retrieval may need to be reassessed, considering the risks and benefits associated with further retrieval attempts, including surgery versus deploying or crushing the stent. In most cases, deploying or crushing the stent is the fastest and safest approach.

27.1.3.8

Emergency surgery

Surgical retrieval of lost stents can be challenging and carries high risk of complications. It should, therefore, only be done under extenuating circumstances.

27.1.3.9

Stent deployment

If a stent is lost inside the coronary circulation and wire position is maintained, deployment may be the safest and fastest treatment strategy. Crossing the lost stent with a balloon can sometimes be challenging: using a small balloon can allow advancement within the lost stent, followed by increasingly larger balloons until deployment is optimized. Sometimes, attempts to advance a balloon through a lost stent may lead to more distal displacement of the stent. If a balloon cannot advance through the lost stent (usually due to stent deformation), crushing of the stent could be performed, as described below.

27.1.3.10

Stent crushing ( Fig. 27.7 )

If wire position is lost within the lost stent and retrieval is not feasible or desired, crushing the stent with another stent can be the strategy of choice, unless the stent is located in a critical location, such as the left main. A coronary guidewire is advanced around the lost stent, a balloon is used to crush the stent against the coronary artery wall, and another stent is placed, “excluding” the lost stent from the coronary circulation. It is important to avoid inadvertently passing through one or more stent struts with the second wire, especially if the lost stent has been partially deployed. This should be suspected if balloon delivery is challenging around the lost stent and rewiring should be performed, ideally using a knuckled polymer-jacketed guidewire ( Fig. 27.8 ). If balloon delivery remains challenging after rewiring, consider rewiring again or using a Glider balloon or a Wiggle guidewire.

Meticulous attention should be given to completely appose the stent struts to the vessel wall to avoid limitations of blood flow through the coronary artery, ideally using intracoronary imaging . Both stent crushing and stent deployment carry risk of restenosis, which is, however, much lower than the potential risk of aggressive stent retrieval attempts. Intentional stent crushing is also being performed during PCI of in-stent coronary chronic total occlusions with encouraging results .

27.1.3.11

Leave in peripheral artery

If the lost stent is removed from the coronary artery into the iliac or femoral vessels but cannot subsequently be removed through the sheath or the vessel wall, the lost stent could be crushed against the iliac or femoral artery wall using a peripheral stent ( Fig. 5.8 ). Distal stent embolization into a small arterial branch (such as a femoral artery branch) may be left untreated, since the distally embolized stents appear to have a benign clinical course. None of the 12 patients with distal stent embolization in three series had clinical sequela. Hence, the risk of extraction usually exceeds the risk of local complications .

27.2.1.1

Guidewire entrapment

• Jailing of the guidewire during bifurcation stenting.

• Guidewire deformation (e.g., during aggressive attempts for guidewire knuckling) ( CTO Manual Online case 24 ).

• Withdrawal of a guidewire with a loop at its tip through a proximal stent ( PCI Manual Online case 33 ) .

• Use of a buddy wire together with a filter-based embolic protection device (see Section 18.8.1.1.3). Inadvertent stenting over the buddy wire can result in entrapment of the filter, that can be very challenging or impossible to remove .

• Severe lesion calcification.

27.2.1.2

Guidewire fracture

• Aggressive pulling of an entrapped guidewire.

• Guidewire over-rotation.

• Atherectomy over a kinked guidewire.

27.2.2.1

Guidewire entrapment

• Some advocate to avoid jailing the side branch guidewire during bifurcation stenting; the risk of side branch occlusion in most cases, however, exceeds the risk of guidewire entrapment.

• Avoid aggressive guidewire manipulation, especially in small branches.

• Straighten guidewire tip before removing through a stent ( PCI Manual Online case 33 , Fig. 27.9 ).

  

27.2.2.2