Abstract
OBJECTIVES
Left atrial appendage intervention is an alternative to oral anticoagulation for thromboprophylaxis in atrial fibrillation. The aim of our study was to compare the incidence of silent cerebral embolisms after surgical and percutaneous intervention and to identify the risk factors for procedure-related silent cerebral embolisms after intervention.
METHODS
This prospective observational study included consecutive atrial fibrillation patients from 2 independent cohorts (left atrial appendage excision (LAAE) cohort and left atrial appendage occlusion cohort) between September 2018 and December 2020. All patients underwent cerebral magnetic resonance imaging before and after the procedure. Silent cerebral embolism was defined as new focal hyperintense lesions detected only on postprocedural sequence.
RESULTS
Thirty-two patients from the LAAE cohort and 42 patients from the occlusion cohort were enrolled. A significantly lower incidence of silent cerebral embolism was observed in the LAAE cohort as compared with occlusion (6.3% vs 54.8%, P < 0.001). In the left atrial appendage occlusion cohort, patients who developed silent cerebral embolism after the procedure had significantly higher CHA2DS2-VASc scores [odds ratio (OR) 2.172; 95% confidence interval (CI) 1.149–4.104; P = 0.017], longer occlusion placement time (OR 1.067; 95% CI 1.018–1.118; P = 0.006) and lower peak activated clotting time level after transseptal puncture (OR 0.976; 95% CI 0.954–0.998; P = 0.035).
CONCLUSIONS
The incidence of procedure-related silent cerebral embolism was strikingly lower in patients with LAAE than in patients with occlusion. More cardiovascular comorbidities, longer occlusion placement time and lower activated clotting time level were significantly associated with the development of procedure-related silent cerebral embolism.
Keywords: Atrial fibrillation, Left atrial appendage, Silent cerebral embolism, Cerebral protection, Magnetic resonance imaging
Cerebral or other systemic thromboembolisms are the catastrophic complications of atrial fibrillation (AF).
INTRODUCTION
Cerebral or other systemic thromboembolisms are the catastrophic complications of atrial fibrillation (AF). Data have shown that ∼90% of emboli originate from the left atrial appendage (LAA) [1]. While oral anticoagulation (OAC) therapy has been the mainstay for thromboembolism prophylaxis in patients with AF, LAA intervention, either by excision (LAAE) or occlusion (LAAO), has been increasingly recognized as an alternative strategy [2, 3]. However, the intervention of the LAA still has room to be improved. Patient selection, incomplete LAA closure [4] and postoperative anticoagulation strategies are the concerns of surgical LAA interventions. On the other hand, LAAO also has its procedural considerations, such as acute complications [5], postoperative anticoagulation strategies, the long-term efficacy [6] and the device-related thrombosis.
Recent reports have demonstrated that radiofrequency catheter ablation on the left side of the heart could cause silent cerebral embolism (SCE) during the procedure [7, 8]. Peri-procedural SCE after LAAO was also reported thereafter [9]. However, these findings are only descriptive, and no further analysis on the risk factors and risk population of SCE after LAAO was mentioned. Transthoracoscopic surgical LAA intervention is another choice to effectively prevent cardiac thromboembolisms in AF patients [10]. However, the passway of surgical intervention is epicardial and non-blood-pool related. This is quite different from percutaneous LAAO. To date, no data regarding the incidence of SCE after LAAE and the comparison of the incidence of SCE between the 2 LAA interventions have been reported.
It is important to note that even a subclinical cerebral embolism has long-term negative effects on the cognitive function of the patients [11–13]. Therefore, we sought to investigate the incidence of SCE in patients receiving different LAA intervention strategies and to identify the procedure-related risk factors associated with SCE.
PATIENTS AND METHODS
Ethics statement
Ethics approval for research was obtained from the ethical committee of the First Affiliated Hospital of Nanjing Medical University, number 2014-SR-113. All enrolled patients provided written informed consent.
Study population
This prospective, observational study was performed at the First Affiliated Hospital of Nanjing Medical University between September 2018 and December 2020.
Consecutive patients who met the indications for surgical LAA intervention from the division of cardiovascular surgery were included in the LAAE cohort [14]. Indications were as follows: (i) symptomatic AF in the absence of structural heart disease refractory to class I/III antiarrhythmic drugs or catheter-based therapy; (ii) contraindications to antiplatelet treatment; and (iii) LAA excision or exclusion in conjunction with surgical ablation for AF for longitudinal thromboembolic morbidity prevention.
Consecutive patients who met the indications for LAAO device implantation from the division of cardiology were included in the LAAO cohort [15]. Indications were as follows: (i) patients with a contraindication for OAC; (ii) patients with an elevated bleeding risk under chronic OAC; (iii) patients unwilling or unable to take OAC; and (iv) patients in whom OAC is inefficient (‘stroke on OAC’).
The exclusion criteria were as follows: (i) age >80 years or <18 years; (ii) contraindications to magnetic resonance imaging (MRI) scan; and (iii) a modified Rankin score ≥4. All the patients were consecutively enrolled within the same period. Decisions were independently made by their outpatient doctors.
Peri-procedural anticoagulation management
In the LAAE cohort, warfarin use was bridged with low-molecular-weight heparin 48 h before the operation, and novel oral anticoagulants were discontinued from the operation day. Antiplatelet drugs were administered at the discretion of cardiac surgeons based on the cardiovascular risk factors. In the LAAO cohort, anticoagulation was not interrupted during the whole procedure and additional aspirin was administered immediately after the procedure.
Left atrial thrombi were routinely screened by transoesophageal echocardiography before the procedure.
Thoracoscopic LAAE with or without AF ablation
All patients were placed under general anaesthesia. As previously described, the procedure was performed via a transthoracoscopic approach [16]. Surgical ablation (if needed) often included epicardial pulmonary vein ablation, epicardial ganglionated plexi ablation, ligament of Marshall dissection and ablation with an AtriCure Isolator Synergy ablation clamp (AtriCure, Inc., Cincinnati, OH) and AtriCure Synergy ablation pen. After ablation, the LAA excision site was closed with an endoscopic EZ 60 stapler (Ethicon EndoSurgery, Inc., Cincinnati, OH) under the guidance of transoesophageal echocardiography.
Percutaneous endovascular LAAO with or without AF ablation
LAAO procedures were performed under conscious sedation. If AF ablation was needed, after creating a double transseptal access into the left atrium, a multielectrode mapping catheter (Pentary, Biosense Webster, Diamond Bar, CA, USA) was inserted for mapping. A 3.5-mm irrigated-tip ablation catheter (Thermocool Smarttouch, Biosense Webster, Diamond Bar, CA, USA) was advanced for ablation. Circumferential pulmonary vein isolation and substrate modification (if needed) were routinely performed.
After AF ablation, the occluders (LAmbreTM device, Lifetech Scientific Corp., Shenzhen, China; or WATCHMAN™ device, Boston Scientific, Marlborough, MA, USA) were advanced into the LAA and then anchored and released in a standard way [17].
For periprocedural anticoagulation, intravenous heparin was given immediately after transseptal puncture to achieve an activated clotting time (ACT) > 250 s (Hemochron® Signature Elite) [15]. If AF ablation was combined, the ACT level was titrated to 300–350 s [18].
The entire procedure time was defined as the time between the successful puncture of the femoral vein and the withdrawal of all sheaths and catheters from the femoral vein. The LA procedure time was defined as the time between the successful transseptal puncture and the withdrawal of all sheaths and catheters from the LA. The LAAO placement time was defined as the time between delivery system advancement to the transportation sheath and successful release of the LAA occluders.
Cerebral magnetic resonance imaging acquisition and analysis
All patients underwent cerebral MRI with a 1.5 T scanner (uMR 570, United Imaging, China) using a 12-channel head–neck coil within 24 h before the procedure and within 7 days after the procedure.
The imaging protocol consisted of the following sequences: axial T1-weighted imaging [repetition time (TR) 1800 ms, echo time (TE) 9 ms, slice thickness 4 mm, field of view (FOV) 220 × 200 mm2, matrix 320 × 256], axial T2-weighted imaging (TR 5090 ms, TE 91 ms, slice thickness 5 mm, FOV 220 × 200 mm2, matrix 320 × 320), axial T2-fluid attenuated inversion recovery sequence (TR 4480 ms, TE 69 ms, slice thickness 5 mm, FOV 220 × 200 mm2, matrix 256 × 256, inversion time 2100 ms); a high-resolution diffusion-weighted imaging with a spin-echo, echo-planar image sequence performed in the axial plane (TR 4480 ms, TE 69 ms, slice thickness 2 mm, FOV 220 × 200 mm2, matrix 192 × 192, b values 0 and 1000 s/mm2).
SCE were defined as new focal hyperintense lesions detected only on postprocedural diffusion-weighted imaging sequences, confirmed by a decreased apparent diffusion coefficient value to rule out a T2 shine-through effect.
MRI images were analysed by 2 junior independent neuroradiologists who were blinded to the clinical characteristics of the patients. A senior 3rd neuroradiologist who was more experienced performed the quantification and made the final decision.
Neurological examinations
Detailed neurological physical examinations were performed before and after the procedure by an experienced neurologist blinded to the MR results.
Statistical analysis
Continuous variables are described as the mean ± SD, and Student’s t-test was used for comparisons between groups. Categorical variables are expressed as frequencies and percentages, and comparisons between groups were made using the χ2 test with the Fisher’s exact test whenever necessary. To determine the independent correlates of procedure-related SCE, univariable logistic regression analysis was performed. Furthermore, the variables with P < 0.1 in the unadjusted model were selected for testing in multivariable analysis. All statistical analyses were performed using SPSS software version 26.0.
RESULTS
We finally enrolled 2 independent cohorts in this study, 1 from the division of cardiovascular surgery and the other from the division of cardiology. In total, 40 consecutive AF patients with a high risk of thromboembolism were enrolled in the LAAE cohort, and 51 patients were enrolled in the LAAO cohort. Two patients who suffered from LAA closure-device disengagement and 1 who suffered from severe pericardial tamponade in the LAAO procedure were excluded. Forty-two patients from the LAAO cohort and 32 from the LAAE cohort (Fig. 1) finished post-operation MRI. Forty patients (19 in the LAAO cohort and 21 in the LAAE cohort) who only received LAA intervention were in AF rhythm during the MRI scanning period after the procedure.
Figure 1:
Study flowchart. Consecutive 40 and 51 atrial fibrillation patients from the division of cardiovascular surgery and the division of cardiology who had received left atrial appendage intervention were included in the 2 independent cohorts.
None of the patients were symptomatic or had any new neurological deficits.
Clinical characteristics of patients in the LAAE cohort and LAAO cohort
The baseline and clinical characteristics were comparable between the 2 cohorts (Table 1). One patient in the LAAO cohort and 5 patients in the LAAE cohort did not take anticoagulants before the procedure because of gastrointestinal bleeding, haemoptysis or ocular bleeding. Thirty (71.43%) patients in the LAAO cohort and 25 (78.13%) patients in the LAAE cohort had old cerebral lesions on the preprocedural MRI scans which was consistent with their previous history of stroke. Two patients (2/74, 2.7%) in LAAO cohort had recent onset new SCE on the preprocedural MRI.
Table 1:
Baseline characteristics of the study patients
| LAAO cohort, N = 42 | LAAE cohort, N = 32 | P-Value | |
|---|---|---|---|
| Age (years) | 69.83 ± 7.26 | 67.91 ± 7.66 | 0.597 |
| Female | 22 (52.38%) | 10 (31.25%) | 0.069 |
| Paroxysmal AF | 9 (21.43%) | 10 (31.25%) | 0.338 |
| Hypertension | 26 (61.90%) | 20 (62.50%) | 0.958 |
| CHD | 13 (30.95%) | 3 (9.38%) | 0.059 |
| Diabetes | 11 (26.19%) | 5 (15.63%) | 0.274 |
| CHA2DS2-VASc score | 4.07 ± 1.81 | 3.72 ± 1.25 | 0.349 |
| HAS-BLED score | 2.36 ± 0.93 | 2.47 ± 0.67 | 0.568 |
| Oral anticoagulants | 41 (97.62%) | 27 (84.38%) | 0.101 |
| Warfarin | 5 (12.20%) | 0 (0.00%) | 0.065 |
| NOAC | 36 (87.80%) | 27 (100.00%) | 0.873 |
| Antiplatelet agents | 0 (0.00%) | 3 (9.38%) | 0.077 |
| LAD (mm) | 42.95 ± 4.41 | 42.97 ± 3.23 | 0.986 |
| LVEF (%) | 62.68 ± 3.15 | 63.50 ± 1.83 | 0.195 |
| Preprocedural cerebral lesions on MRI | 30 (71.43%) | 25 (78.13%) | 0.514 |
Values are mean ± SD or n (%).
AF: atrial fibrillation; CHD: coronary heart disease; LAAE: left atrial appendage excision; LAAO: left atrial appendage occlusion; LAD: left atrium diameter; LVEF: left ventricular ejection fraction; MRI: magnetic resonance imaging; NOAC: novel oral anticoagulants.
Results of postprocedural MRI
LAAE is associated with a significantly lower incidence of SCE (2/32; 6.3%) than LAAO (23/42; 54.8%, P < 0.001) (Fig. 2A). Eleven out of 23 (47.8%) patients in the LAAO cohort who had new SCE suffered from multiple lesions (75 lesions in 23 affected patients), while only 2 lesions in 2 separate patients in the LAAE cohort (Figs. 2A and 3). In the subgroups of patients who received LAAE/LAAO alone, the difference in the incidence of SCE was also significant (9.5% in LAAE alone group vs 42.1% in LAAO alone group, P < 0.001) (Fig. 2B). While in patients who received combined AF ablation, the incidence of SCE was 0% in LAAE combined AF ablation group and 65.2% in LAAO combined AF ablation group (Fig. 2C). Fifty-five out of 77 lesions (71.4%) were < 5 mm in diameter, while 4 (5.2%) were larger than 10 mm (Fig. 2D). Of note, 71.4% of the lesions located in the cortex, which is cognition function related (Fig. 2E), and 50.6% (39/77) of the lesions located in the frontal lobe, where the emotion and memory function is associated (Fig. 2F). No haemorrhages were found peri-procedurally.
Figure 2:
Comparison of the totally 77 lesions detected by magnetic resonance imaging. Lesions in LAAO cohort are significantly larger both in size and number than in LAAE cohort (A and D). The difference remains significant between the subgroups of LAAO/E alone (B) and LAAE/O + Ablation (C). Of note, 47.83% (11/23) LAAO subjects suffered from multiple lesions (A), 71.43% (55/77) lesions are < 5 mm in diameter (D) and located in the cortex (E), 53.25% (41/77) lesions located in frontal lobe (F). LAAE: left atrial appendage excision; LAAO: left atrial appendage occlusion.
Figure 3:
Preprocedural and postprocedural cerebral magnetic resonance imaging. Preprocedural (A, C and E) and postprocedural (B, D and F) diffusion-weighted imaging of the example patients.
Clinical characteristics of patients with or without SCE in the LAAO cohort
The clinical and procedural parameters of the patients with or without SCE in the LAAO cohort are summarized in Table 2. Patients with high CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75, diabetes mellitus, prior stroke or transient ischemic attack (TIA), vascular disease, age 65–74, female) scores and high HAS-BLED (hypertension, abnormal renal or liver function, stroke, bleeding, labile international normalized ratio, elderly, drugs predisposing to bleeding or history of alcohol abuse) scores had a higher risk for SCE. There was no significant difference in age, gender or other cardiovascular comorbidities between the 2 subgroups. In the entire LAAO cohort, the patients with new SCE had significantly longer left atrial procedure time (128.4 ± 56.7 min vs 92.2 ± 55.2 min, P = 0.043) and LAAO placement time (56.1 ± 24.0 min vs 29.0 ± 17.3 min, P < 0.001) than those without new SCE (Table 2). Patients without new SCE tended to need a higher heparin dose (11184.2 ± 3934.2 vs 9695.7 ± 2991.4 units, P = 0.171) than those with SCE. The periprocedural average ACT (293.4 ± 56.6 vs 255.4 ± 35.3 s, P = 0.017) and peak ACT (310.6 ± 55.7 vs 272.0 ± 38.3 s, P = 0.015) were significantly longer in the patients without new SCE.
Table 2:
Comparison of patients with and without new silent cerebral embolism in left atrial appendage occlusion cohort
| New SCE, N = 23 | No SCE, N = 19 | P-Value | |
|---|---|---|---|
| Age (years) | 69.96 ± 6.31 | 67.47 ± 8.23 | 0.275 |
| Female | 13 (56.52%) | 9 (47.37%) | 0.554 |
| Hypertension | 15 (65.22%) | 11 (57.89%) | 0.627 |
| CHD | 8 (34.78%) | 5 (26.32%) | 0.555 |
| Diabetes | 7 (30.43%) | 4 (21.05%) | 0.737 |
| CHA2DS2-VASc | 4.74 ± 1.42 | 3.26 ± 1.94 | 0.007* |
| HAS-BLED | 2.65 ± 0.78 | 2.00 ± 1.00 | 0.022* |
| Oral anticoagulants | 23 (100.00%) | 18 (94.74%) | 0.452 |
| LAD (mm) | 42.70 ± 5.36 | 43.26 ± 3.00 | 0.668 |
| LVEF (%) | 63.10 ± 2.16 | 62.18 ± 4.05 | 0.354 |
| Heparin dose (IUs) | 9695.65 ± 2991.42 | 11184.21 ± 3934.22 | 0.171 |
| Baseline ACT (s) | 134.61 ± 28.26 | 151.32 ± 35.48 | 0.097 |
| Average ACT (s) | 255.39 ± 35.31 | 293.37 ± 56.57 | 0.017* |
| Peak ACT (s) | 271.96 ± 38.27 | 310.63 ± 55.66 | 0.015* |
| Entire procedure time (min) | 154.04 ± 64.79 | 123.21 ± 64.02 | 0.131 |
| LA procedure time (min) | 128.43 ± 56.71 | 92.21 ± 55.17 | 0.043* |
| LAAO placement time (min) | 56.13 ± 23.98 | 29.00 ± 17.33 | <0.001* |
| Times of deployment | 1.70 ± 0.97 | 1.26 ± 0.45 | 0.067 |
| Times of retrieve | 0.70 ± 0.97 | 0.26 ± 0.45 | 0.067 |
| Times of occluder exchange | 2 (8.70%) | 2 (10.53%) | 1.000 |
| LAAO only | 8 (34.78%) | 11 (57.89%) | 0.134 |
| WATCHMAN device | 15 (65.22%) | 10 (52.63%) | 0.408 |
Values are mean ± SD or n (%). *P < 0.05.
ACT: activated clotting time; CHD: coronary heart disease; LA: left atrial; LAAO: left atrial appendage occlusion; LAD: left atrium diameter; LVEF: left ventricular ejection fraction; SCE: silent cerebral embolism.
The SCE incidence (65.2% vs 42.1%, P = 0.134) tended to increase in patients who underwent LAAO plus AF ablation when compared with those who underwent LAAO only, but the differences were not statistically significant (Table 3).
Table 3:
Univariable and multivariable logistic regression analysis for SCE during left atrial appendage occlusion procedure
| Characteristics | Univariate analysis |
Multivariable analysis |
||||
|---|---|---|---|---|---|---|
| OR | 95% CI | P-Value | OR | 95% CI | P-Value | |
| Age (years) | 1.051 | (0.962–1.149) | 0.271 | |||
| Female | 1.444 | (0.426–4.897) | 0.555 | |||
| Hypertension | 1.364 | (0.390–4.766) | 0.627 | |||
| CHD | 1.493 | (0.393–5.668) | 0.556 | |||
| Diabetes | 1.641 | (0.398–6.761) | 0.493 | |||
| CHA2DS2-VASc score | 1.743 | (1.115–2.724) | 0.015* | 2.172 | (1.149–4.104) | 0.017* |
| HAS-BLED score | 2.345 | (1.082–5.082) | 0.031* | |||
| NOAC | 2.800 | (0.453–17.318) | 0.268 | |||
| LAD (mm) | 0.970 | (0.843–1.117) | 0.675 | |||
| LVEF (%) | 1.104 | (0.894–1.362) | 0.358 | |||
| Heparin dose (IUs) | 1.000 | (1.000–1.000) | 0.173 | |||
| Baseline ACT (s) | 0.983 | (0.963–1.004) | 0.105 | |||
| Average ACT (s) | 0.982 | (0.966–0.997) | 0.021* | |||
| Peak ACT (s) | 0.982 | (0.967–0.997) | 0.019* | 0.976 | (0.954–0.998) | 0.035* |
| Entire procedure time (min) | 1.008 | (0.998–1.018) | 0.133 | |||
| LA procedure time (min) | 1.012 | (1.000–1.025) | 0.052 | |||
| LAAO placement time (min) | 1.065 | (1.022–1.109) | 0.003* | 1.067 | (1.018–1.118) | 0.006* |
| Times of deployment | 2.319 | (0.848–6.344) | 0.101 | |||
| Times of retrieve | 2.319 | (0.848–6.344) | 0.101 | |||
| Times of occluder exchange | 0.810 | (0.103–6.362) | 0.841 | |||
| LAAO only | 2.578 | (0.768–9.010) | 0.138 | |||
| WATCHMAN device | 0.410 | (0.171–2.056) | 0.593 | |||
ACT: activated clotting time; CHD: coronary heart disease; CI: confidence interval; LA: left atrial; LAAO: left atrial appendage occlusion; LAD: left atrium diameter; LVEF: left ventricular ejection fraction; NOAC: novel oral anticoagulants; OR: odds ratio.
*P < 0.05.
Risk factors for SCE during the LAAO procedure
We performed univariate and multivariate analyses to identify the risk factors for procedure-related SCE in the LAAO cohort (Table 3). In the univariate analysis, the significant risk factors for SCE were CHA2DS2-VASc score (P = 0.015), HAS-BLED score (P = 0.031), periprocedural average ACT (P = 0.021), peak ACT (P = 0.019), LA procedure time (P = 0.052) and LAAO placement time (P = 0.003). Furthermore, the multivariate analysis revealed that CHA2DS2-VASc score [odds ratio (OR) 2.172; 95% confidence interval (CI) 1.149–4.104; P = 0.017], peak ACT (OR 0.976; 95% CI 0.954–0.998; P = 0.035) and LAAO placement time (OR 1.067; 95% CI 1.018–1.118; P = 0.006) were independent predictors of SCE.
DISCUSSION
This prospective pilot study was the 1st to report the incidence of procedure-related SCE after LAAE. We found that patients who underwent LAAE (6.3%) had a strikingly lower incidence of new SCE than those who underwent LAAO (54.8%). Furthermore, we identified several risk factors associated with LAAO procedure-related SCE, including higher CHA2DS2-VASc score, lower peak ACT level and longer LAAO placement time.
Patients enrolled in our study had a 2.7% incidence of pre-operation SCE which might be related to AF itself and was comparable with previous studies [19].
Risk factors contributing to SCE development
As described in previous studies on catheter ablation, possible reasons for the development of SCE during catheter-based procedures are char formation or ablated tissue on the catheter tip, thrombus formation along the catheters and sheaths, plaque shift and activation of the coagulation cascade and introduction of gaseous material during sheath exchanges [20]. LAAO is also a catheter-based procedure, but with a larger, long sheath and a metallic foreign occluder. Although LAAO-related SCE has been described [9], its aetiology, high-risk population and procedure-related risk factors have not been analysed in detail. As a promising alternative strategy for stroke prevention, patients who undergo transcatheter LAAO has a surprisingly high incidence of SCE according to our observations. The possible risk factors might be categorized into 2 aspects: (i) Population-related factors. In patients with more cardiovascular comorbidities, the LA endothelial function might be more impaired and the thrombogenic state might be promoted. (ii) Procedure-related factors. A prolonged LAAO procedure leads to more chances of SCE development. During the procedure, frequent catheter exchange as well as occluder replacement or retrieval would be more likely to activate the coagulation cascade or dislodge pre-existing LA microthrombi. At the same time, ACT level could also have a conceivable impact on the incidence of SCE. Further studies should be conducted to determine the most appropriate ACT level for LAAO procedures or the role of cerebral embolic protection in high-risk patients.
Possible explanations for the lower SCE incidence in the LAAE cohort
Despite of the comparable baseline characteristics between the 2 cohorts, the rate of SCE in our surgical group was significantly lower. Furthermore, unlike the LAAO cohort who received full anticoagulation during the entire peri-procedure period, oral anticoagulants were discontinued peri-procedurally in all the surgical patients. This paradoxical result can only be explained by the fact that, in surgical prevention, it is epicardial and non-blood-pool passway. This indirectly proved that percutaneous interventional procedures using sheaths, catheters, guiding wires and occluders are highly pro-thrombotic and need intensified periprocedural anticoagulation management. The extremely lower SCE incidence in surgical LAAE might provide further insight into the patient selection when choosing LAA interventions.
Of note, the development of SCE during surgical intervention is not close to none. This might be caused by the non-notifiable pre-existed clots harboured the inside LAA. Therefore, preprocedural anticoagulation should still be emphasized.
The potential impact of SCE on neurocognitive function and clinical implication
Although SCE detected by MRI might be gradually resolved by the follow-up MRI [21], the neurocognitive effects might be long-lasting [22, 23] because cerebral necrosis persists even after radiological resolution. Considering that postprocedural SCE is a sign of brain damage, its long-term impact on cognition disorders should not be overlooked.
Given the significantly lower incidence of periprocedural SCE in patients undergoing LAAE, mini-invasive thoracoscopic epicardial LAAE might deserve consideration for high-risk patients, especially for those patients with pre-existing cognition dysfunction. Since a high level of ACT during the LAAO procedure can dramatically decrease the incidence of SCE, LAAE may also be an alternative option for patients with a high risk of bleeding.
Limitations
This study also has several limitations. First, the patients were from 2 independent cohorts, which might have caused selection bias, and further randomized controlled studies are necessary to verify the current observations. Second, the overall sample size was relatively small. A small sample size will limit further detailed analysis of the risk factors for SCE. Finally, the impact of SCE on cognitive function should be evaluated during a long-term follow-up based on the present results.
CONCLUSION
This study showed a strikingly lower incidence of procedure-related SCE in patients with transthoracoscopic surgical LAAE than in patients with transcatheter LAAO. More cardiovascular comorbidities, a longer LAAO placement time and a lower ACT level after transseptal puncture appear to contribute significantly to the development of SCE in patients with LAAO. The disparity between surgical LAAE and transcatheter LAAO in terms of the risk of procedure-related SCE might be an important consideration when we intend to select right patients for right procedure.
ACKNOWLEDGEMENTS
The authors would like to thank Drs Yongfeng Jia and Shujing Ren for their contribution to MRI data analysis and Dr Pipin Kojodjojo from Cardiac Department, National University Heart Centre, Singapore, for language polishing. All coauthors provided final approval of the version to be published and agree to be accountable for all aspects of the work presented.
Glossary
ABBREVIATIONS
- ACT
Activated clotting time
- AF
Atrial fibrillation
- CI
Confidence interval
- FOV
Field of view
- LAA
Left atrial appendage
- LAAE
Left atrial appendage excision
- LAAO
Left atrial appendage occlusion
- MRI
Magnetic resonance imaging
- OAC
Oral anticoagulation
- OR
Odds ratio
- SCE
Silent cerebral embolism
- TE
Echo time
- TR
Repetition time
Contributor Information
Zidun Wang, Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Kexin Wang, Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Shanshan Lu, Division of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Lian Zhang, Division of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Mingfang Li, Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Weizhu Ju, Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Buqing Ni, Division of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Weidong Gu, Division of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Yongfeng Shao, Division of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Minglong Chen, Division of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Funding
None.
Conflict of interest: The authors have no conflicts of interest to declare.
DATA AVAILABILITY
The data underlying this article will be shared on reasonable request to the corresponding author.
Author contributions
Zidun Wang: Resources; Writing—original draft. Kexin Wang: Data curation; Formal analysis; Writing—original draft; Writing—review & editing. Shanshan Lu: Data curation. Lian Zhang: Data curation. Mingfang Li: Methodology; Writing—review & editing. Weizhu Ju: Data curation; Methodology; Writing—review & editing. Buqing Ni: Data curation; Resources. Weidong Gu: Data curation; Resources. Yongfeng Shao: Data curation; Resources. Minglong Chen: Investigation; Methodology.
Reviewer information
European Journal of Cardio-Thoracic Surgery thanks Terezia B. Andrasi and the other anonymous reviewer(s) for their contribution to the peer review process of this article.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data underlying this article will be shared on reasonable request to the corresponding author.
Author contributions
Zidun Wang: Resources; Writing—original draft. Kexin Wang: Data curation; Formal analysis; Writing—original draft; Writing—review & editing. Shanshan Lu: Data curation. Lian Zhang: Data curation. Mingfang Li: Methodology; Writing—review & editing. Weizhu Ju: Data curation; Methodology; Writing—review & editing. Buqing Ni: Data curation; Resources. Weidong Gu: Data curation; Resources. Yongfeng Shao: Data curation; Resources. Minglong Chen: Investigation; Methodology.
Reviewer information
European Journal of Cardio-Thoracic Surgery thanks Terezia B. Andrasi and the other anonymous reviewer(s) for their contribution to the peer review process of this article.