Thrombosuction for Procedural Acute Thrombosis During High-Risk Carotid Angioplasty – A Case Report

ABSTRACT: Carotid endarterectomy in the presence of an occluded contralateral artery is associated with a high risk of perioperative stroke. Carotid stenting with neuroprotection devices has emerged as a safe procedure for revascularization in this circumstance. We performed high-risk carotid angioplasty in a patient with a history of recurrent transient ischemic attacks and 90% stenosis of left internal carotid artery with other occluded cerebral vessels. The final follow-up angiogram revealed thrombotic obstruction of the stent without any evidence of vasospasm, stent deformation or dissection. Direct thrombosuction was performed with the guiding sheath. Multiple suction passes yielded complete restoration of vascular patency and intracranial flows. A control angiogram performed 10 days later revealed no residual stenosis or thrombus. Thrombosuction using a guiding sheath leads to rapid revascularization in a patient with acute carotid stent thrombosis.

J INVASIVE CARDIOL 2010;22:E144–E146

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Atherosclerosis of the carotid artery is an important cause of stroke, with a reported incidence of 5–7% per year in patients with a > 70% stenosis of the carotid arteries.¹ Carotid endarterectomy is regarded as the gold-standard therapy for primary and secondary prevention of stroke. However, carotid endarterectomy in the presence of an occluded contralateral artery has been associated with a high risk of perioperative stroke (5.1–14.3%). This is mainly due to reduced collateral circulation during carotid clamping or cerebral hemorrhage secondary to the hyperperfusion syndrome.^2,3 Carotid stenting with neuroprotection devices has emerged as a safe procedure for carotid revascularization.⁴ It may be an attractive alternative to surgical carotid endarterectomy, especially when the surgical risk is too high. The major periprocedural complications during carotid stent placement include transient or permanent neurologic deficit due to distal thrombus embolization and, rarely, acute stent thrombosis. A well-established antithrombotic regimen and use of distal embolic protection device may help in overcoming these complications. We report a case of acute stent thrombosis during filter-protected carotid stent placement despite combined antiplatelet and antithrombotic therapy. We also discuss the management issues involved in such a case. Case Report. A 62-year-old male with a history of coronary artery disease and hypertension presented for the evaluation of recurrent transient ischemic attacks. Clinical examination revealed feeble pulses and unrecordable blood pressure in both the upper limbs and a bruit over the left carotid artery was noted. There was no focal neurological deficit. Echocardiography showed regional wall-motion abnormalities in the anterior and inferior wall, with a left ventricular ejection fraction of 40%. Coronary angiography showed a normal left main coronary artery, a recanalized left anterior descending artery, a totally occluded but well collateralized left circumflex coronary artery and a normal right coronary artery. Magnetic resonance imaging (MRI) of the brain showed lacunar infarcts in the fronto-parietal, occipito-parietal and pontine territories bilaterally. Magnetic resonance angiography (MRA) revealed high-grade stenosis of the left internal carotid artery (LICA) with occlusion of other cerebral vessels (right brachiocephalic, right common and internal carotid, right vertebral, left vertebral arteries) (Figure 1). Cerebral angiography confirmed the MRA findings, revealing a 90% stenosis (NASCET criteria) of LICA along with other occluded cerebral vessels.⁵ The Circle of Willis was complete and the entire cerebral circulation was dependent on the LICA. The patient was sent for high-risk LICA angioplasty in view of the increased morbidity associated with carotid endarterectomy. He was started on a combination of aspirin and clopidogrel prior to angioplasty. Heparin (5,000 IU) was administered and the left common carotid artery (LCCA) was cannulated with a 6 Fr right diagnostic catheter over a stiff 0.035" exchange wire and a 7 Fr Super Arrow Flex 90 cm sheath (Arrow International) was placed in the LCCA. The patient’s intracranial circulation was reassessed angiographically and no significant changes were noted compared to the earlier report. An EPI Filterwire EZ (Boston Scientific Corp., Natick, Massachusetts) was placed distal to the LICA lesion for embolic protection. After predilating the lesion with a 3.5 x 10 mm coronary balloon at 6 atm, a nitinol Precise 9 x 40 mm stent (Cordis Corp., Miami Lakes, Florida) was placed across the lesion and deployed. The stent was postdilated with a 6 x 20 mm Slalom balloon (Cordis) at 8 atm. The stent was successfully deployed, with no residual stenosis. However, after removal of the EPI Filterwire, the final follow-up angiogram revealed mild haziness in the stented segment which progressively increased over a period of time, resulting in thrombotic obstruction of the stent (Figure 2). There was no evidence of vasospasm, stent deformation or dissection. The patient soon developed seizures and hemodynamic instability. Seizures were controlled with diazepam and phenytoin sodium. The activated clotting time (ACT) was 208 seconds and he was given urokinase (500,000 units), along with a bolus dose of abciximab (0.125 mg/kg), into the LICA. Several thrombo-aspiration runs of the Export catheter (Medtronic, Inc., Minneapolis, Minnesota) were done with no benefit. As a backup to the wall measure, direct thrombosuction was performed with the guiding sheath. The Arrow sheath was taken up to the level of the thrombus and active suction was performed (Figure 3). Multiple suction passes led to the complete restoration of vascular patency and intracranial flows (Figure 4). The patient improved hemodynamically and clinicallly. A computed tomographic scan of the head was done after the procedure to rule out any intracranial bleeding. The patient was continued on antiplatelet agents and heparin for 7 days after this procedure. A control angiogram performed 10 days later revealed no residual stenosis or thrombus. Subsequent MRI of the brain did not show any fresh focal neurological lesions. Discussion. This case highlights a rare complication of acute stent thrombosis during carotid stenting that was managed energetically by performing thrombosuction using the guiding sheath by a team of multidisciplinary physicians (interventional cardiologist, anesthesiologist and neurologist). Patients with bilateral carotid artery disease in which one artery is totally occluded have a poor prognosis with medical therapy.⁷ The incidence of stroke for asymptomatic patients on medical therapy is 38% over 6 years of follow up, while it is 69% for symptomatic patients over 2 years of follow up.3 Carotid stenting has emerged as an attractive alternative to surgical carotid endarterectomy in these cases due to the high rate of complications.^2,3 Acute or subacute stent thrombosis is a rare complication encountered in patients undergoing carotid stenting.^6,7 Among patients on an optimal antithrombotic regimen, it may be caused by dissection, vasospasm and atheroma prolapse. The reason for acute stent thrombosis in our patient remained obscure. By a systematic process of exclusion, we ruled out dissection, stent deformation, vasospasm and atheroma prolapse. Peri-interventional carotid stent thrombosis requires rapid initiation of reperfusion therapy to limit the time of brain ischemia. The underlying mechanism of stent thrombosis has to be analyzed rapidly to facilitate appropriate therapy.⁸ The most important step in the therapeutic strategy is recanalization of the occluded stent either by intra-arterial thrombolysis or mechanical thrombectomy. Thrombolytic therapy achieved complete recanalization of only 19% of the involved arteries after neuroendovascular interventional thrombotic events.^9,10 As thrombolytic agents simultaneously exert clot-dissolving and procoagulant action, combining them with antiplatelet agents (facilitated thrombolysis) improves the rate of recanalization.¹¹ However, the strategy of facilitated thrombolysis did not work in our case. Mechanical thrombectomy using the Angiojet (Medrad/Possis Medical, Minneapolis, Minnesota) device, Neuronet device and Microsnare has been reported to improve the rate and speed of recanalization of the thrombosed arteries.^12–15 In the present case, the Medtronic Export catheter was tried unsuccessfully initially, as no other thrombectomy device was available. The guiding sheath was used subsequently for thrombosuction as the last resort. This was used as a bailout procedure in the present case, and no similar reports were found in the literature. The strategy of facilitated thrombolysis along with thrombosuction led to rapid revascularization and prevented neurological damage in a patient whose cerebral circulation was totally dependent on the LICA. Conclusion. The bailout strategy of thrombosuction using the guiding sheath led to rapid revascularization in a patient with acute carotid stent thrombosis. References

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From the ^*Department of Cardiology, Artemis Health Institute, Gurgaon, India; ^§Department of Cardiology, Command Hospital, Kolkata, Índia; and the ^£Department of Cardiology, Command Hospital, Bangalore, India. The authors report no conflicts of interest regarding the content herein. Manuscript submitted December 23, 2009 and accepted January 7, 2010. Address for correspondence: Davinder S. Chadha, MD, DM, Department of Cardiology, Command Hospital, Bangalore, Karnataka 560017 India. E-mail: agiamu@gmail.com