Migrated coronary stent into the left internal carotid artery: a rescue technique

Abstract

Coronary stent dislodgement and migration is a rare phenomenon that can potentially result in life-threatening complications. We encountered the unusual case of a coronary artery stent that stripped from its delivery balloon and embolised into the left internal carotid artery during percutaneous coronary intervention. Such an event is a stressful experience for the interventional cardiologist but also an uncommonly encountered situation for a neurointerventionalist whose expertise may be sought to help navigate the situation. Planning the interventional approach and taking into consideration the tools available as well as potential complications is crucial to maximise the chances of best possible outcome for the patient. We were able to retrieve the stent safely and successfully, but, at the same time, we were prepared to manage any adverse events in the best way possible.

Background

Stent migration and loss is a rare complication during percutaneous coronary interventions.^{1 2} It is even rarer for the stent to enter and eventually lodge in the internal carotid artery. Foreign body removal from the internal carotid artery is a risky but necessary undertaking. A foreign body in the internal carotid artery poses a risk for further intracranial migration and/or clot formation with the risk of thromboembolic and ischaemic complications. Proper approach planning is needed to minimise procedural complications and increase the chances of successful retrieval. We here describe the case of a drug-eluting stent migration during coronary artery intervention with lodging of the stent in the left distal cervical/petrous internal carotid artery.

Case presentation

A patient in their early 50s with medical history of hypertension, coronary artery disease, obesity and prior COVID-19 infection experienced pressure-like chest pain with exertion over several days which became constant on the day of presentation. The pain started in the epigastric region and later spread to across the chest wall and ultimately to the left upper extremity. In the emergency room, laboratory tests were notable for elevated troponin to 0.93 ng/mL, white blood cell count of 10.8 10*3/uL, haemoglobin of 14.7 g/dl and haematocrit of 42%, creatinine of 0.96 mg/dL, sodium of 138 mmol/L, potassium of 4 mmol/L and glucose of 105 mg/dL. COVID-19 PCR, influenza A/B and RSV were negative. ECG showed sinus tachycardia without ischaemic changes and a heart rate of 106. Patient was hypertensive to 210 systolic and 130 diastolic. CXR showed no specific evidence of pneumonia or interstitial oedema. The patient was diagnosed with non-ST-elevation myocardial infarction in the setting of acute coronary syndrome with unstable angina and started on heparin and nitroglycerine drip. The patient also received Crestor 40 mg, Lopressor 12.5 mg two times per day, a dose of aspirin 325 mg, intravenous morphine 4 mg and intravenous Zofran 4 mg. The patient was admitted to the cardiology service. Repeat ECG showed normal sinus rhythm with heart rate in the low 90 s and no evidence of ischaemia. Second troponin value rose to 6.55 ng/mL, and blood pressure remained elevated at 178/111. The patient underwent coronary angiography which revealed multifocal coronary artery stenoses, most severe in the proximal left anterior descending coronary artery (80%), mid-left circumflex coronary artery (70%) and right posterior descending coronary artery (80%).

After a multidisciplinary team discussion, the patient was determined to be a poor surgical candidate and was scheduled to undergo percutaneous coronary intervention of the left anterior descending (LAD) and possibly left circumflex (LCx) coronary arteries under moderate sedation. Drug-eluting coronary stents were successfully placed in the LAD. Catheterisation of the LCx was difficult due to excessive vessel angulation. Initially a 2.0×30 mm Resolute Onyx drug-eluting coronary stent (Medtronic, Irvine, California, USA) was advanced which would not traverse the angulated LCx despite the use of a support catheter. During the attempt to withdraw the stent, it stripped from the delivery balloon into the ascending aorta. The patient remained asymptomatic.

The intervention was continued, and eventually the coronary lesion was rewired and overlapping drug-eluting stents were placed in the mid-LCx.

Investigations

On completion of the coronary intervention, the interventional cardiologist attempted to identify the location of the dislodged coronary stent under live fluoroscopy but was not confidently able to locate the stent. After the procedure, a CT angiogram of the head and neck was urgently obtained which showed the dislodged coronary stent in the distal left cervical/petrous internal carotid artery (ICA) (figure 1). The patient continued to remain asymptomatic and neurologically intact.

Figure 1.

Sagittal CT angiogram maximum intensity projection image shows the coronary stent lodged in the left petrous internal carotid artery.

Treatment

After the CT angiogram, the patient was directly taken to the angiography suite for cerebral angiograms and possible foreign body retrieval under general anaesthesia.

First, a right internal carotid artery angiogram was obtained which showed blood flow to the contralateral left anterior cerebral artery territory via a patent anterior communicating artery but no flow to the left middle cerebral artery territory. Next, a left common carotid artery angiogram was obtained which showed unchanged position of the migrated coronary stent, lodged within the left internal carotid artery at the level of the skull base (figure 2A,B). Given the collateral status and the location of the migrated stent, it was decided to proceed with foreign body retrieval.

Figure 2.

Intraprocedural frontal fluoroscopy image confirms the position of the coronary stent at the level of the skull base (arrow in A), and left common carotid artery injection shows flow beyond the coronary stent in an intact vessel (arrow in B).

The interventional setup consisted of a 0.087-inch Walrus balloon guide catheter (95 cm length, Q’Apel Medical, Fremont, California, USA), a 0.058-inch Catalyst 5 distal access catheter (115 cm length, Stryker Neurovascular, Fremont, California, USA) and a 10 mm Amplatz Goose neck Snare (120 cm length, eV3, Minneapolis, Michigan, USA). The balloon guide catheter was chosen to achieve proximal flow control in the event of a complication such as a vessel rupture during the attempt to remove the stent. The Catalyst 5 catheter offers good support when distally navigating a device. It is also important to note that the Snare is available in a length of 120 cm and the Catalyst 5 is one of the few intermediate catheters that is available in a 115 cm length to accommodates the Snare catheter. Using this catheter combination, we were able to permit the Snare to sufficiently extend beyond the tip of the intermediate catheter and engage the stent.

The balloon guide catheter was placed in the left proximal ICA, and the Catalyst 5 catheter was advanced into the mid-portion of the left cervical ICA. The Snare was then advanced within the Catalyst 5 catheter, and it successfully captured the proximal portion of the coronary stent (figure 3A). Subsequently, the Snare was withdrawn into the Catalyst 5 catheter, and both were removed together (figure 3B demonstrates the Snare that captured the coronary stent).

Figure 3.

Frontal view fluoroscopy image shows successful capture of the coronary stent using the Snare catheter (arrow in A) and the captured stent within the snare after removal (B).

Outcome and follow-up

Follow-up frontal and lateral view angiograms via balloon guide catheter contrast injection showed a patent and intact left ICA with only mild vasospasm at the site of the retrieved stent. Follow-up intracranial angiograms showed normal flow in the left anterior circulation and no evidence of thromboembolic complication. After the procedure, the patient was successfully extubated and awoke without any neurological deficits. The patient was discharged 24 hours later.

Discussion

Coronary stent migration and loss during percutaneous coronary intervention is an uncommon phenomenon.^{1 2} Incidences range between 0.3% and 8.3%^1–4 and have decreased over the years with the development of balloon-mounted stents. Mechanisms of stent loss include dislodgement from the delivery balloon during loading of the stent–balloon assembly into the guide catheter, dislodgement during stent implantation or dislodgement during catheter pullback^4–6 which occurred in our case. Stent dislodgement is more commonly seen during interventions in very tortuous and severely calcified coronary vessels.^4–6 If encountered, stents most commonly dislodge into the coronary arteries,^{7 8} the ascending aorta⁹ or peripherally the lower extremity vasculature.^{10 11} Embolisation of a coronary stent into the head and neck vasculature is an exceptionally uncommon event. Unfortunately, this scenario may be associated with significant neurological complications in the setting of thromboembolic events, vessel injury and/or occlusion. Therefore, a neurointerventionalist may perceive such a situation as stressful given its rare nature and the potentially devastating consequences.

In our case, we highlight the importance of proper case evaluation and review of the procedural steps to be familiar with the vascular anatomy and to maximise the chances of best possible outcome for the patient. Procedural planning includes evaluation of cerebral blood flow from the contralateral circulation in the unfortunate event of a complication that may have required vessel sacrifice. Additionally, compatibility of all catheters and devices must be verified prior to their usage during the procedure. In this case, it was crucial to select a supportive and short intermediate catheter to accommodate the 120 cm length of the Snare catheter.

Being prepared for the ‘worst case scenario’ may make all the difference in the event of a vessel dissection or tear with active contrast extravasation. Use of a balloon guide catheter allows for inflation of the balloon and proximal flow control. Knowing the patient’s vascular anatomy and presence of collateral flow from the contralateral anterior circulation and/or the posterior circulation can help to quickly decide between vessel sacrifice (deconstructive approach) and preservation (reconstructive approach) in the event of a complication.

Learning points.

• Evaluation of intracranial collateral blood flow is crucial to know if vessel sacrifice may be a safe option.

• Assurance of interventional tool compatibility (ie, catheter lengths) ahead of the procedure is important for a successful procedure without unnecessary delays/difficulty.

• Awareness of and planning on what to do in the event of a complication (ie, vessel injury, extravasation) can save the patient’s life.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).