Carotid Artery Stenting Following Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis: A Case Report

Abstract

Objective: During the perioperative period of carotid artery stenting (CAS), severe aortic stenosis (AS) is associated with a risk of serious complications, such as cardiac arrest. There is no consensus regarding the order of treatment for patients with severe AS concomitant with proximal carotid artery stenosis. We herein report a case in which CAS following transcatheter aortic valve implantation for severe AS was safely performed in an older high-risk patient.

Case Presentation: An 84-year-old woman presented with severe aortic stenosis that required treatment. Magnetic resonance angiography revealed severe left proximal internal carotid stenosis. Cerebral blood flow measurements revealed a normal cerebral perfusion. An uneventful transcatheter aortic valve implantation for severe aortic stenosis was followed by carotid stenting at a 2-month interval.

Conclusion: Staged treatment may be a safe and effective strategy in high-risk patients with concomitant severe AS and carotid stenosis. In cases with a normal cerebral blood flow, CAS following transcatheter aortic valve implantation can be a reasonable option, especially in older patients with multiple comorbidities.

Introduction

During the perioperative period of carotid artery stenting (CAS), severe aortic stenosis (AS) is associated with a risk of serious complications, such as bradycardia, hypotension, and cardiac arrest.¹⁾ AS induced by degeneration of the aortic valve increases with age. Age-related AS accounts for >80% of patients with severe AS requiring surgery.²⁾ We encountered older patients with severe AS concomitant with carotid stenosis. There is no consensus regarding the order of treatment for patients with severe AS concomitant with carotid stenosis. Transcatheter aortic valve implantation (TAVI) has recently emerged as a treatment option for patients with severe AS, particularly older or high-risk patients. Few reports have described simultaneous or staged CAS after TAVI.

We herein report an older high-risk patient with severe aortic stenosis concomitant with severe carotid artery stenosis. After a careful evaluation of cerebral perfusion and individualized treatment planning, CAS was successfully performed following TAVI.

Patient consent was obtained for the publication of this study.

Case Presentation

The patient was an 84-year-old woman with a history of arrhythmias. Echocardiography showed severe AS with an aortic valve area (AVA) of 0.88 cm²: the AVA index was 0.54 cm²/m²; the Vmax was 4.39 m/s; and the peak pressure gradient was 77 mmHg. Therefore, the patient required treatment for severe AS. Preoperatively, magnetic resonance angiography (MRA) revealed a severe ICS on the left side (Fig. 1A). The medical history included atrial fibrillation, hypertension, and liver cirrhosis. The patient had no history of neurological symptoms. Laboratory data revealed thrombocytopenia secondary to liver cirrhosis. Black-blood magnetic resonance imaging revealed a high-intensity left carotid plaque on the T1 sequence and a low-intensity plaque on the T2 sequence, which was diagnosed as a lipid-rich plaque (Fig. 1B). Computed tomography angiography (CTA) showed 80% stenosis of the proximal left internal carotid artery with semicircular calcification according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria (Fig. 1C). Cerebral blood flow measurements using single-photon emission computed tomography (SPECT) demonstrated normal cerebral perfusion in both cerebral hemispheres. The treatment of asymptomatic but severe carotid stenosis with vulnerable plaques should be considered. Considering the patient’s medical condition and advanced age, CAS could be indicated if the severe AS improved with treatment. We decided to perform TAVI first, followed by CAS. TAVI for severe AS was performed uneventfully using a bovine pericardial bioprosthesis (Fig. 2A and 2B). Two months after TAVI, echocardiography showed improvement in AS with a Vmax of 2.38 m/s, and a peak pressure gradient of 23 mmHg. CAS was performed at our hospital after a 2-month interval. The patient received 30 mg edoxaban and 75 mg clopidogrel before CAS. A 5 Fr guiding sheath was introduced into the left common carotid artery using the right transfemoral approach. CAS was performed with a distal protection device (Filter-Wire EZ; Boston Scientific, Natick, MA, USA). The left ICS was dilated with a balloon dilatation catheter (AVIATOR PLUS; diameter, 5.0 mm; length, 30 mm; Cordis, Miami Lakes, FL, USA) under 6 atmospheres of pressure for 30 seconds, and a PRECISE PRO RX of 9 mm in diameter and 30 mm in length (Cordis) was deployed between the proximal internal carotid artery and distal common carotid artery, covering the entire stenotic lesion (Fig. 3A–3C). Post-balloon dilatation was not performed. Transient hypotension due to carotid sinus reflex was treated with intravenous dopamine for 2 days after CAS. There were no neurological events after CAS, and there were no ischemic lesions on the postoperative MRI. The postoperative course was uneventful. Follow-up 3D CTA performed 6 months after CAS demonstrated good patency of the lesion without restenosis.

Fig. 1 MRA shows proximal left internal carotid artery with 80% stenosis (A). Black-blood magnetic resonance imaging showing a high-intensity lipid-rich plaque in the T1 sequence (B). CT shows semicircular calcification of the proximal internal carotid artery (C).

Fig. 2 A bovine pericardial bioprosthesis was deployed at the aortic valve (A). The bovine pericardial bioprosthesis placed in the correct position (B).

Fig. 3 Left internal carotid angiography shows an irregular short segment with 80% stenosis at the proximal internal carotid artery (A). A balloon of 5 mm in diameter and 30 mm in length was inflated at the stenotic segment using a distal protection device (Filter-Wire EZ) (B). Left internal carotid angiography showing submaximal dilation of the proximal internal carotid artery, with the stent covering the entire lesion (C). Filter-Wire EZ, Boston Scientific, Natick, MA, USA

Discussion

Carotid endarterectomy and CAS are the standard surgical treatments for carotid stenosis. Randomized control trials, such as SAPPHIRE, CREST, and ACT-1, have demonstrated that CAS is non-inferior to carotid endarterectomy (CEA), and that CAS is increasing.^3–5) However, it is generally contraindicated for patients with severe AS because of the risk of serious complications such as cardiac arrest during the perioperative period.¹⁾ AS increases with age, as degeneration of the aortic valve induces AS. Age-related AS accounts for more than 80% of patients with severe AS requiring surgery.²⁾ In the general population, severe AS accounts for <1% of cases in patients <70 years of age, but approximately 7% in those >80 years of age.⁶⁾ We have more older patients with severe AS concomitant with internal carotid stenosis. It has been reported that 69 of 761 patients (9%) with symptomatic severe AS who underwent TAVI had ≥70% severe stenosis of the internal carotid artery.⁷⁾ Few reports have described CAS following TAVI for severe AS.⁸⁾

The risk of CAS in patients with severe AS is high. Previous reports have documented hemodynamic collapse during CAS in patients with untreated AS, which resulted in serious complications. In patients with severe AS, perioperative bradycardia and hypotension after CAS induce a sudden drop in blood pressure and shock or cardiac arrest.⁹⁾ A previous study reported that 1 of 5 cases in which CAS was performed before TAVI required emergency balloon aortic valvuloplasty due to hemodynamic collapse.¹⁰⁾ If possible, CAS should be performed after treatment for severe AS.

In recent years, TAVI has become a feasible treatment option for severe AS, particularly in older patients with multiple comorbidities. However, TAVI can induce hypotension and a complete atrioventricular block during the periprocedural period. As hypotension and complete atrioventricular block after TAVI are risk factors for cerebral ischemia, special care must be taken, and it should be promptly managed to stabilize cerebral perfusion with strict perioperative blood pressure management.^11–13) In this case, we asked the cardiologist to avoid hypotension as much as possible during TAVI. Previous studies reported that the frequency of perioperative stroke is approximately 14% in surgical aortic valve replacement (SAVR) or TAVI for severe AS.¹⁴⁾ On the other hand, other studies reported that ICS is an independent risk factor for perioperative stroke in SAVR¹⁵⁾ but that it is not associated with stroke in TAVI.¹⁶⁾ TAVI is considered safer for perioperative neurological complications, and we were able to perform CAS after TAVI without any complications.

SPECT with acetazolamide challenge is useful for predicting peri-TAVI strokes. In patients with normal cerebral perfusion and cerebrovascular reactivity, TAVI can be performed with a low risk of cerebral ischemia. There is no consensus regarding the interval between TAVI and CAS. Simultaneous TAVI and CAS may increase procedural risk. Considering the possibility of hypotension and complete atrioventricular block following TAVI, CAS should be performed after hemodynamic stability is achieved.

In the present case, we selected a staged approach based on the careful evaluation of cerebral perfusion confirmed by SPECT and the characteristics of the carotid plaque confirmed by black-blood MRI. As the patient had normal cerebral perfusion with normal cerebrovascular reactivity and a stable carotid plaque, TAVI could be safely performed, and CAS could be delayed until hemodynamic stability post-TAVI. These cautious and individualized approaches have led to successful outcomes without perioperative complications. Our case suggests that staged interventions may be safer in patients with normal cerebral perfusion than simultaneous TAVI and CAS.

Conclusion

CAS is generally contraindicated in patients with severe AS because of the risk of perioperative cardiovascular instability. In cases of normal cerebral perfusion, CAS following TAVI after a certain interval to achieve hemodynamic stability may be safe and effective. This case emphasizes the importance of individualized treatment planning based on a careful evaluation of cerebral perfusion and carotid plaque characteristics.

Disclosure Statement

All authors have no conflict of interest.

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