Guidewire complications

Overview
The use of coronary guidewires can be associated with perforation of the epicardial coronary artery, entrapment of the wire in the vessel, wire fracture and detachment or embolization of the wire tip. This chapter discusses the management of these complications

Definition and Incidence
Coronary perforations are uncommon (< 1%) complications of percutaneous coronary intervention (PCI) and are associated with significant morbidity and mortality rates. Coronary perforations are infrequent in patients undergoing balloon angioplasty (0.1%) compared with patients undergoing atheroablative therapy (1.3%; P< 0.001)  Perforation due to coronary guidewires may present late after the procedure.

Risk Factors
The use of hydrophilic wires and wires in which the court extends to the tip are wire characteristics associated with perforation. Lesions with the highest risk of perforation include chronic total occlusions.

Diagnosis
Perforation is an angiographic diagnosis. It appears as a small extraluminal extravasation of blush in the distribution of the target vessel. Care should be taken to routinely visualize the distal extent of the vessel following PCI to exclude the presence of a wire perforation. Emergency echocardiography should be performed to rule out the presence of a pericardial effusion or pericardial tamponade.

Prognosis
The prognosis following coronary perforation depends on the extent of extravastion into the pericardium.

Classification
The following classification scheme has been developed based on angiographic appearance of the perforation:
 * Type I perforations including an extraluminal crater without extravasation
 * Type II perforations containing pericardial or myocardial blushing
 * Type III perforations having a ≥ 1 mm diameter with contrast streaming; and cavity spilling.

Coronary Artery Perforation
Shown below is perforation of the right coronary artery during PCI: 


 * Class I perforations were associated with no deaths and cardiac tamponade in 8% of patients.
 * Class II perforations were associated with no deaths and cardiac tamponade in 13% of cases
 * Class III perforations were associated with death in 19% and cardiac tamponade in 63% of patients.

Management of Vessel Perforation
Initial management strategies include:
 * 1) Prolonged balloon inflation: For this reason it is often wise for a cardiac catheterization laboratory to have perfusion balloons in a range of sizes available.
 * 2) Reversal of anticoagulation: This would included administration of protamine to reverse heparin and administration of platelets if abciximab has been administered.
 * 3) In refractory cases, polytetrafluoroethylene covered stents (stent grafts) can be used to seal the perforation.
 * 4) The administration of platelets can be considered to reverse the effects of antiplatelet agents.
 * 5) The administration of protamine can be considered to reverse the effects of unfractionated heparin. Protamine will also partially reverse the antithrombotic effect of enoxaparin if this antithrombin was used.
 * 6) Other techniques include coil embolization, the injection of clotted blood, the use of gel foam and the injection of thrombin at the site of the perforation.

Approximately one third of cases of PCI-associated coronary artery perforation require emergent cardiac surgery.

Pseudolesions
A pseudolesion is a stenosis that appears in an artery after the coronary gidewire is placed in the artery.

Risk Factors for Pseudolesions
Pseudolesions appear in tortuous sections of vessels that have been straightened out by the guidewire. Tortuous right coronary arteries and left internal mammary arteries are at risk for pseudolesion formation.

Differential Diagnosis of Pseudolesions
A pseudolesion must be distinguished from a dissection or coronary spasm.

Diagnosis of Pseudolesions
A pseudolesion will usually disappear if the wire is withdrawn to the distal edge of the lesion and the vessel is allowed to assume its normal shape. Sometimes replacement of a stiff wire with a more flexible floppy wire eliminates that pseudolesion. In addition, either a microcatheter or a balloon catheter can be placed distal to the lesion and this will sometimes eliminate the pseudolesion. If the balloon kinks at the site of vessel tortuosity, then it can be hard to reintroduce the wire. A pseudolesion should completely disappear after the wire is withdrawn from the coronary artery.

Treatment of Pseudolesions
Pseudolesions should not be stented or dilated!

Complications of Pseudolesions
In some cases pseudolesions may cause hemodynamic compromise and ischemia. Inadvertent stenting of pseudolesions by overzealous interventional cardiologists.

Guidewire Entrapment
Guidewire entrapment is more likely to occur in the following scenarios:


 * In the presence of calcified vessels (for example the RCA)
 * Repeated use of the same wire for multiple interventions
 * Repeated attempts at crossing the same lesion multiple times with the same wire
 * Two wires may become entrapped when the "buddy wire" technique is used
 * Crossing fresh stent struts

Management of Guidewire Entrapment

 * One technique is to advance a small profle balloon or a small caliber catheter (transit catheter) to the “attachement” site and pull back gently. Care must be taken not to cause perforation when advancing the small profile balloon.
 * When a second or "buddy wire" gets trapped between a stent and the vessel wall gentle traction can be used to free the wire from the stent. The coating of the tip may “deglove” and be left behind. This technique may result in wire tip embolization.
 * The entangled wire can be “pushed and pasted” against the vessel wall with another stent.
 * Surgery may be required retrieve the entrapped guidewire.

Guidewire Fracture and Embolization
Risk factors for guidewire entrapment and fracture include the presence of a calcified lesion, the performance of bifurcation stenting and prolonged procedures in which the guidewire is manipulated extensively.

Care should be taken to remove the guidewire from the body very slowly so as to not result in distal embolization of the wire tip. If resistance is felt as the wire is being pulled back, further investigation should be made as to whether the wire is entrapped in a stent strut or other structure.

Management of Guidewire Tip Embolization

 * If the embolized tip is small and cannot be retrieved, a stent can be used to “push and paste” it to the vessel wall.
 * For large or long pieces of embolized tip that cannot be retrieved or in the setting of thrombosis, surgery may be required.

Snaring the Embolized Wire Fragment
There are several devices that can be used to snare the fragment.
 * The Amplatz Gooseneck Microsnare manufactured by eV3 Incorporated, Plymouth Minnesota: This device is made up of three loops measuring 2, 4, and 7 mm. The device the device is contained in advanced via a 2.3 French microcatheter and the loop used to lasso the guidewire extends from this.  Once the guidewire is ensnared, the loop is withdrawn from the body and this closes the loop ensnaring the guidewire.
 * The EnSnare Triple Loop Device: In this device, there are three loops each oriented at hundred 120° from the other.
 * The X Pro Micro Elite Snare: This device also has loops of 2, 4 and 7 mm.
 * The Alligator Retrieval Device made by Chestnut Medical Technologies Incorporated of Menlo Park California: This device is made up of jaws that are attached to the tip of a wire. The 4 jaws of this device close when a 0.021 inch micro catheter is advanced.

Prognosis
In the largest published series of eight patients, there were no complications among the five patients in whom the guidewire could be snared and removed. In the other three patients, the guidewire was retained inside of a chronic total occlusion.