Table of Contents
Year : 2021  |  Volume : 6  |  Issue : 3  |  Page : 181-186

Association between stroke and carotid artery blood block interval in trans-carotid transcatheter aortic valve replacement: A retrospective observational study

1 Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai 200032; Department of Cardiology, Shanghai Xuhui District Central Hospital, Shanghai 200030, China
2 Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai 200032, China

Date of Submission24-Jul-2021
Date of Acceptance09-Sep-2021
Date of Web Publication30-Sep-2021

Correspondence Address:
Da-Xin Zhou
Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai 200032
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2470-7511.327241

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Objectives: Patients undergoing trans-carotid transcatheter aortic valve replacement (TC-TAVR) are more likely to suffer from a stroke because of cerebral blood hypoperfusion and blood occlusion caused by the introducer sheath compared with the trans-femoral (TF) approach. The present study aimed to compare the incidence of stroke between the TC and TF approaches and explore the causes of stroke after TAVR. Methods: We retrospectively reviewed the medical records of 414 consecutive patients with severe aortic valve stenosis who underwent TC- or TF-TAVR at our center from October 2010 to November 2019; these patients were included in this observational study. The clinical data, such as the incidence of stroke, were compared between TC- and TF-TAVR patients. The correlation between carotid artery blood block interval (CABBI) and neurological events was also analyzed. The study was approved by the Ethics Committee of Zhongshan Hospital of Fudan University (approval No. YL2014-32). Results: Patients undergoing TC-TAVR had a significantly higher incidence of stroke than those undergoing TF-TAVR (12.5% vs. 0, P < 0.001), whereas the baseline data and the incidence of other complications did not differ significantly between the patients undergoing TC- and TF-TAVR (P > 0.05). Moreover, in TC-TAVR patients, the average CABBI of stroke was significantly longer than that of nonstroke patients (61.7 ± 20.7 min vs. 25.1 ± 1.6 min, P = 0.001). The number of patients with CABBI >30 min in the stroke group was greater than that in the nonstroke group (P < 0.001). Conclusions: In the absence of the cerebral and carotid artery evaluation before TAVR, surgeons should take into consideration the time of CABBI <30 min to avoid the possibility of stroke.

Keywords: Carotid artery blood block interval; Stroke; Trans-carotid approach; Transcatheter aortic valve replacement; Trans-femoral approach

How to cite this article:
Yang LF, Pan WZ, Guan LH, Zhang XC, Zhang L, Chen SS, Zhou DX, Ge JB. Association between stroke and carotid artery blood block interval in trans-carotid transcatheter aortic valve replacement: A retrospective observational study. Cardiol Plus 2021;6:181-6

How to cite this URL:
Yang LF, Pan WZ, Guan LH, Zhang XC, Zhang L, Chen SS, Zhou DX, Ge JB. Association between stroke and carotid artery blood block interval in trans-carotid transcatheter aortic valve replacement: A retrospective observational study. Cardiol Plus [serial online] 2021 [cited 2021 Nov 27];6:181-6. Available from:

Authors Li-Fan Yang, Wen-Zhi Pan contributed equally to this work.

  Introduction Top

Aortic valve stenosis (AVS) is the most commonly acquired valvular disease in adults. Transcatheter aortic valve replacement (TAVR) was developed as an effective and standard therapy for patients with severe AVS and trans-femoral (TF) access is the most widely used approach for TAVR. However, the TF approach is not feasible for TAVR candidates who have peripheral vascular diseases and small-caliber iliofemoral vasculature.[1] Therefore, in such cases, trans-carotid (TC), trans-aortic, trans-apical, and subclavian approaches are preferred. Asians usually have petite builds with small vasculatures. Therefore, the TC approach is most often employed in Asian countries such as China. Compared with TF access, TC access does not divide the chest cavity or any muscles, thereby hastening the healing of the neck wound and reducing the duration of hospital stay.[2] TC-TAVR is also a comparatively easier technique for valve deployment according to the superficial and less calcified carotid arteries. Our results showed a high success rate of TC-TAVR, which were consistent with some other research.[3] It has also been shown that TC approach has similar outcomes compared with the TF approach regarding mortality and morbidity.[4],[5]

Furthermore, neurological safety before and during TC-TAVR includes the assessment for cerebral blood occlusion. Most researchers have indicated the necessity of preoperative evaluation of the cerebrovascular anatomy; it has been found that patients with ≥50% stenosis or presence of a plaque are at a high risk for embolization.[6],[7] Cerebral protection is beneficial for reducing cerebral lesions on magnetic resonance imaging (MRI) in patients undergoing TAVR. The insertion of large sheaths for aortic valves through the TC approach and the increase in the time of hypoperfusion through the circle of Willis could potentially increase the risk of stroke.[1] However, most patients developing multiple new lesions distributed in the two hemispheres through the TC approach had no postoperative neurological or cognitive dysfunction.[8] Several studies[9],[10],[11],[12] suggest that the carotid artery blood block interval (CABBI) is associated with neurological symptoms during carotid artery intervention. However, the incidence of stroke following TC- or TF-TAVR and the relationship of CABBI and neurological events remain unclear. Therefore, this study aimed to investigate the relationship between CABBI and neurological events in a patient cohort undergoing TAVR.

  Materials and Methods Top

Study population

This was a retrospective observational study that analyzed the data of 414 consecutive patients with severe AVS who underwent TC-or TF-TAVR in Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, from October 2010 to November 2019. The study cohort flow diagram is shown in [Figure 1]. The inclusion criteria were as follows: (i) valve oval area <1 cm2 or mean pressure gradient ≥40 mmHg; (ii) feasible anatomical structure for TAVR; (iii) refusal surgical valve implantation or high risk for surgical valve replacement; and (iv) symptomatic AVS with New York Heart Association class ≥II. Patients who had any infection and outflow obstructive cardiomyopathy were excluded. A baseline evaluation involving transthoracic echocardiography with multiple-slice computed tomography angiography (MSCT) was performed to evaluate the anatomy of the aortic root and the diameter, calcification, and patency of the femoral and carotid arterials to determine the approach of TAVR and valve size. For each patient, the TF approach was initially considered and the TC approach was a secondary choice if the diameter of the femoral artery was <5.6 mm (the TAVR device in China needing an 18 Fr or larger introducer sheath) or if there was severe calcification or tortuosity.
Figure 1: The study cohort flow diagram.
CABBI: Carotid artery blood block interval, TC-TAVR: Trans-carotid transcatheter aortic valve replacement, TF-TAVR: Trans-femoral transcatheter aortic valve replacement

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The procedures were performed using fluoroscopy and were conducted at our center in a hybrid room. General anesthesia and transesophageal ultrasound were performed during the procedure. For TF-TAVR, the femoral artery was punctured and closed using the Vascular Perclose ProGlide™ device (Abbott Inc., Chicago, IL, USA). During the operation, the introducer sheath was inserted prior to crossing of the aortic valve. For TC-TAVR, the proximal left common carotid artery (CCA) was exposed before the procedure and sutured by a surgeon after the procedure by a surgeon. However, before the carotid artery was sutured, carotid angiography was performed in patients with carotid stenosis. During TC-TAVR, the CABBI was defined as the interval between the introducer sheath advancing to the carotid arteries to the withdrawal of the introducer sheath, which was inserted after the crossing of the aortic valve and the placement of an extra-stiff wire in the left ventricle. A double antiplatelet medication was administered for 6 months after TAVR to prevent thrombosis. Self-expanding valves were used in all patients. The valves used for TC- or TF-TAVR in this study included Venus-A valve (Venus Medical, Hangzhou, China), Medtronic CoreValve (Medtronic, Minneapolis, MN, USA), and VitaFlow (Microport, Shanghai, China).

Data collection

Data were collected from December 2019 to February 2020 using the inpatient electronic medical record system. Baseline characteristics including age, sex, previous medical history, aortic valve calcification (AVC) score, and echocardiographic data were collected before the procedure. The AVC image was obtained using MSCT angiography; the AVC score was calculated using the Agatston method.[13] Previously, the European Society of Cardiology recommended cutoff values for the AVC Agatston Score to assess the likelihood of severe aortic stenosis according to AVC load.[14],[15] Perioperative outcomes (duration of hospital stay and D-dimer) and complications were recorded postoperatively. Stroke was diagnosed based on clinical symptoms, physical signs, and cerebral computed tomography results. Stroke was defined as quoted in the valve academic research consortium-2 consensus document,[16] as an acute episode of focal or global neurological dysfunction caused by the brain, spinal cord, or retinal vascular injury as a result of hemorrhage or infarction. The present study mainly discusses ischemic stroke. Neurological dysfunction after stroke is defined as a change in the level of consciousness, hemiplegia, hemiparesis, numbness, or sensory loss affecting one side of the body, dysphasia or aphasia, hemianopia, amaurosis fugax, or other neurological signs or symptoms consistent with stroke. The diagnosis of stroke was carried out by a neurologist or a neurosurgical specialist in our study.[9],[10]

Ethics statement

The study was approved by the Ethics Committee of Zhongshan Hospital of Fudan University (Approval No. YL2014-32) and conducted in compliance with the 1964 Declaration of Helsinki, as revised in 2013. This study is reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement guidelines. All participants provided informed consent.

Statistical analysis

Continuous variables and categorical variables were presented as mean values ± standard deviation and number (percentages), respectively. Continuous variables were compared by independent-samples t-test. Categorical variables were compared using the Chi-square test or Fisher's exact test (when the sample size was <40). All P values were based on two-sided tests and were considered statistically significant at P < 0.05. Statistical analyses were performed using the SPSS version 13.0 software package (SPSS Inc., Chicago, IL, USA). The sample size was estimated by software PASS 11 (NCSS, LLC. Kaysville, UT, USA).

  Results Top

Characteristics of the study patients

A total of 414 patients with severe AVS (332 men and 82 women) were enrolled in this study. Of all the patients, 48 underwent TC-TAVR and 366 underwent TF-TAVR. The procedure success rates of the TC and TF groups were 100% and 97%, respectively. Two patients underwent emergency surgery due to valve dislodgement, and one patient died from complications with ventricular fibrillation in the TF group. The baseline data were not significantly different between the TC-TAVR and TF-TAVR groups (P > 0.05). The demographic and perioperative data are shown in [Table 1].
Table 1: Baseline characteristics and operative data

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Comparisons of procedure outcomes before discharge between trans-carotid- and trans-femoral transcatheter aortic valve replacement groups

Except for stroke (P < 0.01), there were no differences in the duration of hospital stay, D-dimer level, incidence of death, and complications between the two groups during the duration of their hospital stay [P > 0.05; [Table 2].
Table 2: Perioperative outcomes before discharge

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Association between strokes and carotid artery blood block interval

In the TC-TAVR group, six patients (12.5%) experienced cerebral blood hypoperfusion. The rate of neurological events between the TC and TF approach was significantly different (12.5% and 0, P < 0.001). Four of these patients (8.3%) experienced weakness of the right arm but recovered within 7 days. Cerebral CT revealed ischemic softening lesions. The average time of CABBI was 48.8 ± 6.3 min. Two other patients, whose CABBI time was 90 and 85 min, respectively, recovered within one month. Cerebral CT revealed multiple infarctions. The average CABBI time of the six stroke patients was significantly longer than that of nonstroke patients (61.7 ± 20.7 min vs. 25.1 ± 1.6 min, P = 0.001). The percentages of CABBI >30 min in the stroke and nonstroke groups were 100% and 9.5%, respectively (P < 0.001). The percentages of CABBI <30 min in the stroke and nonstroke groups were 0 and 90.5%, respectively (P = 0.000). There were no other significant differences in the baseline characteristics between stroke and nonstroke patients [Table 3].
Table 3: The baseline and perioperative data between stroke and nonstroke in trans-carotid group

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  Discussion Top

Our study is the first to reveal the relationship between stroke and CABBI during TC-TAVR. The primary findings of our study are as follows: (1) in absence of carotid or cerebrovascular evaluation, the TC-TAVR approach has a higher rate of stroke compared to TF-TAVR and (2) higher incidence of stroke during the TC-TAVR approach may be related to a longer CABBI.

In China, TAVR devices require an 18 Fr or larger introducer sheath; therefore, the TC approach was chosen if the size of the femoral artery was <5.6 mm. The TF approach is not feasible in approximately 15% of the patients. Conversely, up to 30,000 patients may undergo non-TF-TAVR each year in the European Union and Northern American territories.[4] Asians usually have a more petite build than Europeans and Americans. Therefore, the TC-TAVR is a popular surgical approach for the Chinese patient population.

In our study, the incidence of stroke for TC-TAVR was 12.5%, which was higher than that reported in other studies (1.6%−2.5%).[4],[5],[6],[7] This may be attributed to the lack of preoperative evaluation procedures for the carotid arteries before TAVR. Cerebral magnetic resonance angiography and carotid Doppler ultrasonography are usually performed to examine the cerebral and carotid vessels before TAVR.[4],[5],[6],[7] If the functional integrity of the circle of Willis is limited, intraoperative use of a femoro-carotid external shunt is required.[7] The balloon occlusion test has been proven to predict the outcome of vessel occlusion and can be used to examine the risk of stroke. In a study by Tanaka et al.,[9] a clinical balloon occlusion test was performed for 15 min in 11 patients. A decrease in cerebral blood flow of >20% was observed in nine patients, and two of them showed a decrease of >40%. However, there were no ischemic symptoms with the hypotensive balloon occlusion test. To study longer times for carotid artery occlusion, studies by Marshall et al.[10] and Sugawara et al.[12] enrolled 25 and 40 patients, respectively, wherein the carotid artery test occlusion was performed for 30 min. Marshall et al. found that five patients (20%) experienced arm weakness and 12 patients had a drop in cerebral blood flow to below 30 mL/100 g/min. Similarly, Sugawara et al. observed neurologic symptoms in four patients (10%), and 10 patients experienced moderate to severe hypoperfusion without neurological symptoms. The CCA can partially maintain ipsilateral cerebral blood flow, and the distal CCA remains intact during TC-TAVR.[2] Clinically silent cerebral infarctions are common after TAVR, and the proportion of new cerebral lesions on MRI is 68%, while the rate of apparent stroke is only 4%.[17],[18] Our study demonstrated that the most important reason for stroke is attributed to CABBI in TC-TAVR during surgery. Cerebral blood hypoperfusion of 30 min is the key distinction between stroke and nonstroke during surgeries. Without preoperative evaluation of cerebral and carotid arteries before TAVR, surgeons should consider the time of CABBI and ensure that the CABBI is under 30 min to avoid the possibility of stroke.


Our study has two limitations. First, before TAVR, all patients underwent a basic examination, excluding carotid Doppler ultrasonography or cerebral magnetic resonance angiography. We could not analyze the influence of cerebral and cervical vascularity on stroke during TC-TAVR. Kochar et al.[19] also reported the lack of interaction between carotid disease and stroke. The CCA partially maintained the ipsilateral cerebral blood flow and the distal CCA remains intact during TC-TAVR; the CCA is never completely occluded.[20] Thus, it was not necessary to perform cerebral magnetic resonance angiography or oximetry monitoring and screening for carotid disease before TAVR as it may limit the benefit of TAVR. Second, even though our study was a comparatively a large sample-sized single-center study in China, its sample size was too small for estimating the incidence analysis of stroke.

  Conclusion Top

Surgeons should consider the time of CABBI <30 min to avoid the possibility of stroke if the preoperative evaluation of the cerebral and carotid arteries before TAVR is lacking.

Institutional review board statement

The study was approved by the Ethics Committee of Zhongshan Hospital of Fudan University (Approval No. YL2014-32).

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms from the patients. In the forms, the patients have provided consent for their images and other clinical information to be published. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity.

Financial support and sponsorship

The study was supported by Shanghai Science and Technology Commission “Science and Technology Innovation Action Plan” Biomedical Science and Technology Support Project Guide (Nos. 16441908100 and 16441901502) and National Key RandD Program of China (No. 2020YFC2008100). The funding sources had no role in the design of this study and did not have any role during its execution, analyses, data interpretation, or decision to submit the manuscript.

Conflicts of interest

Jun-Bo Ge is an Editorial Board member of Cardiology Plus. He was blinded from reviewing or making decisions on the manuscript. The article was subject to the journal's standard procedures, with peer review handled independently of these Editorial Board members and their research groups.

  References Top

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  [Figure 1]

  [Table 1], [Table 2], [Table 3]


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