Device Loss and Entrapment in Contemporary PCI
Device Loss and Entrapment in Contemporary PCI
Our case series demonstrates that device loss or entrapment is an infrequent complication of contemporary PCI. Device loss could be successfully managed percutaneously in all cases, whereas device entrapment required coronary artery bypass graft surgery in most cases.
Stents were the most commonly lost devices. The reported incidence of stent loss is <1% in most contemporary PCI series ( Table 3 ). The incidence of stent loss in our series (0.21%) is the lowest ever reported, and is likely a reflection of the improvements in stent design, adjunctive equipment, and stenting techniques. The most common cause of stent loss in our series was attempts to deliver a stent through a previously deployed stent. Similarly, Kozman et al reported that 6 of 23 stent dislodgements (26%) occurred while passing through a previously placed stent. Stenting distally to proximally may prevent such a complication, although occasionally the need for distal stenting does not arise until after a proximal stent is deployed, for example in cases of distal edge dissection. Sometimes stent deformation can occur during attempts to cross the lesion and then the stent is stripped off while attempting to withdraw it into the guide catheter. Stent delivery through a deeply engaged "mother and child" guide catheter, a Guideliner catheter, or a Proxis catheter may facilitate stent delivery and prevent stent loss. Other factors contributing to stent loss are tortuosity and calcification. Careful preparation of challenging lesions before stent delivery (with predilation, atherectomy, etc.)could also optimize stent delivery and lower the risk of stent loss.
Another important observation from ours and other series is that stent retrieval is not always necessary; in the majority of stent loss cases in our series, the stent was deployed (or crushed with another stent) either because retrieval failed (in 1 case) or as the default strategy (in 2 cases). Indeed, stent deployment in a coronary segment that is unlikely to be significantly affected by stenting may be the most time-efficient and low-risk strategy, as stent retrieval attempts can prolong the procedure, increase radiation exposure, and result in distal stent embolization or target vessel injury. 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 (Figure 1).
Our series shows that apart from stents, other devices can be lost or entrapped during PCI. These devices range from coronary guidewires to femoral arterial sheaths. Often these devices are bulkier than the stents, which may facilitate retrieval, but may also result in compromised antegrade flow and severe ischemia.
The incidence of wire entrapment is under-reported. When a guidewire fractures, the distal spring coil may unravel, creating a metal "bird's nest" that could predispose to thrombosis (Figure 4F and 4G). In cases of guidewire fracture, it is important to perform intravascular ultrasonography to confirm that no wire coil unraveling has occurred. In such cases, covering the guidewire with a stent may suffice, although successful percutaneous wire fragment removal techniques have been described.
Device loss or entrapment can be a severe complication leading to emergency surgery or death. Because it is infrequent, most operators may not have large experience on how to approach such patients. Moreover, some cardiac catheterization laboratories may not stock retrieval equipment or may have limited familiarity with its use. That is why regular review of the various retrieval techniques and equipment is important. Training in retrieval techniques is similar to training on how to extinguish a fire or how to respond to an earthquake. It is possible that one may never experience such an event, but if one does, knowing how to best respond can make the difference between recovery, emergency surgery, or death.
We commonly use snares through a guiding catheter, because the snare delivery catheters are often too short. For retrieval of intracoronary lost devices (usually stents) the MicroElite snare (which is 0.014′ in diameter, has loop size of 2-7 mm, is 180 cm in length and does not require a delivery catheter) or the 2 mm En Snare are commonly utilized. For retrieving objects in the aorta (for example, retrogradely externalized guidewires), an 18-30 mm Ensnare through a JR4 or multipurpose diagnostic or guide catheter is our snare of choice, because of the 3-loop design that facilitates object retrieval. However, it should be used with caution as the snare wires may cause vessel injury.
Our study has important limitations. It was a retrospective analysis from a single center with extensive experience in treating complex patients. The device types lost or entrapped were heterogeneous, limiting the ability to provide broad generalizations of the findings, but providing a comprehensive report of what device loss or entrapment may occur in a contemporary cardiac catheterization laboratory. The equipment used in our patients may not be available in all cardiac catheterization laboratories. Almost all patients were men, although it is unknown whether gender differences exist in device loss or retrieval.
Discussion
Our case series demonstrates that device loss or entrapment is an infrequent complication of contemporary PCI. Device loss could be successfully managed percutaneously in all cases, whereas device entrapment required coronary artery bypass graft surgery in most cases.
Stents were the most commonly lost devices. The reported incidence of stent loss is <1% in most contemporary PCI series ( Table 3 ). The incidence of stent loss in our series (0.21%) is the lowest ever reported, and is likely a reflection of the improvements in stent design, adjunctive equipment, and stenting techniques. The most common cause of stent loss in our series was attempts to deliver a stent through a previously deployed stent. Similarly, Kozman et al reported that 6 of 23 stent dislodgements (26%) occurred while passing through a previously placed stent. Stenting distally to proximally may prevent such a complication, although occasionally the need for distal stenting does not arise until after a proximal stent is deployed, for example in cases of distal edge dissection. Sometimes stent deformation can occur during attempts to cross the lesion and then the stent is stripped off while attempting to withdraw it into the guide catheter. Stent delivery through a deeply engaged "mother and child" guide catheter, a Guideliner catheter, or a Proxis catheter may facilitate stent delivery and prevent stent loss. Other factors contributing to stent loss are tortuosity and calcification. Careful preparation of challenging lesions before stent delivery (with predilation, atherectomy, etc.)could also optimize stent delivery and lower the risk of stent loss.
Another important observation from ours and other series is that stent retrieval is not always necessary; in the majority of stent loss cases in our series, the stent was deployed (or crushed with another stent) either because retrieval failed (in 1 case) or as the default strategy (in 2 cases). Indeed, stent deployment in a coronary segment that is unlikely to be significantly affected by stenting may be the most time-efficient and low-risk strategy, as stent retrieval attempts can prolong the procedure, increase radiation exposure, and result in distal stent embolization or target vessel injury. 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 (Figure 1).
Our series shows that apart from stents, other devices can be lost or entrapped during PCI. These devices range from coronary guidewires to femoral arterial sheaths. Often these devices are bulkier than the stents, which may facilitate retrieval, but may also result in compromised antegrade flow and severe ischemia.
The incidence of wire entrapment is under-reported. When a guidewire fractures, the distal spring coil may unravel, creating a metal "bird's nest" that could predispose to thrombosis (Figure 4F and 4G). In cases of guidewire fracture, it is important to perform intravascular ultrasonography to confirm that no wire coil unraveling has occurred. In such cases, covering the guidewire with a stent may suffice, although successful percutaneous wire fragment removal techniques have been described.
Device loss or entrapment can be a severe complication leading to emergency surgery or death. Because it is infrequent, most operators may not have large experience on how to approach such patients. Moreover, some cardiac catheterization laboratories may not stock retrieval equipment or may have limited familiarity with its use. That is why regular review of the various retrieval techniques and equipment is important. Training in retrieval techniques is similar to training on how to extinguish a fire or how to respond to an earthquake. It is possible that one may never experience such an event, but if one does, knowing how to best respond can make the difference between recovery, emergency surgery, or death.
We commonly use snares through a guiding catheter, because the snare delivery catheters are often too short. For retrieval of intracoronary lost devices (usually stents) the MicroElite snare (which is 0.014′ in diameter, has loop size of 2-7 mm, is 180 cm in length and does not require a delivery catheter) or the 2 mm En Snare are commonly utilized. For retrieving objects in the aorta (for example, retrogradely externalized guidewires), an 18-30 mm Ensnare through a JR4 or multipurpose diagnostic or guide catheter is our snare of choice, because of the 3-loop design that facilitates object retrieval. However, it should be used with caution as the snare wires may cause vessel injury.
Study Limitations
Our study has important limitations. It was a retrospective analysis from a single center with extensive experience in treating complex patients. The device types lost or entrapped were heterogeneous, limiting the ability to provide broad generalizations of the findings, but providing a comprehensive report of what device loss or entrapment may occur in a contemporary cardiac catheterization laboratory. The equipment used in our patients may not be available in all cardiac catheterization laboratories. Almost all patients were men, although it is unknown whether gender differences exist in device loss or retrieval.
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