Novel thrombosis diagnostic strategies: left lateral decubitus computed tomography before catheter ablation in patients with atrial fibrillation

doi:10.21203/rs.3.rs-1620613/v1

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Research Article

Novel thrombosis diagnostic strategies: left lateral decubitus computed tomography before catheter ablation in patients with atrial fibrillation

https://doi.org/10.21203/rs.3.rs-1620613/v1

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Background

Assessing thromboembolic risk is important for patients with atrial fibrillation. The use of new scanning techniques in clinical practice has not been sufficiently investigated. This study aimed to determine the efficacy of left lateral decubitus computed tomography for diagnosing left atrial appendage (LAA) thrombus as a screening tool before catheter ablation and to evaluate the risk factors for thrombus formation.

Methods

This retrospective cohort study included 101 patients. All patients underwent transthoracic echocardiography (TTE) and left lateral decubitus cardiac computed tomography (CT). Transesophageal echocardiography (TEE) was provided only to confirm the LAA thrombus. Patients with allergic reactions to iodide, increased creatinine levels, hyperthyroidism, pregnancy, and age < 18 years were excluded. The CHA₂-DS₂-VASc and HAS-BLED scores were calculated in each patient.

Results

All LAA thrombi detected on CT were confirmed on TEE. Higher CHA2-DS2-VASc, HAS-BLED scores, enlarged left atrium, and the anteroposterior dimension of the left atrium were significantly associated with LAA thrombus. An LAA cauliflower shape is a predictor of LAA thrombus. An increase of LAA volume by 1 cm³ increases the chances of LAA thrombus and cerebral infarct by 2%. The growth of the LAA anteroposterior size by 1 cm increases the risk of LAA thrombus by 2.9 times and of cerebral infarct by 78%. An increase in the CHA2DS2-VASc score by 1 point increases the risk of thromboembolism and cerebral infarction by 12%.

Conclusion

Cardiac CT with the patient positioned on the left side is a good screening tool to determine LAA thrombus and provides highly useful information for predicting thrombosis formation risk in LAA.

Computed tomography

left atrial appendage thrombosis

left lateral body position

Cardioembolism is one of the major causes of ischemic stroke and accounts for 15–30% of all cerebral infarctions [1, 2]. Atrial fibrillation (AF) accounts for up to 60% of cardioembolic strokes [3]. The process by which patients with AF experience a stroke is widely understood. Once the patient develops AF, the dysrhythmia causes contractile dysfunction and stasis, which further leads to thrombus formation and increased risk of thromboembolism [4]. Approximately 90% of all thrombi are localized in the left atrial appendage (LAA) [5, 6, 7, 8].

Current therapeutic strategies for AF include both pharmacological and non-pharmacological approaches [9]. Electrical cardioversion with radiofrequency pulmonary vein antral isolation is one of the effective approaches to the treatment of patients with persistent AF [10, 11]. However, the presence of blood clots in the LAA is a contraindication for electric cardioversion [12, 13]. After normalization of sinus rhythm, restoration of contractility and blood flow can lead to detachment of a blood clot in the LAA and subsequent cardioembolic stroke. Assessing the risk of stroke in patients with AF is critical. The gold standard for the detection of LAA thrombus remains transesophageal cardiography (TEE) [14, 15]. However, TEE is a semi-invasive procedure with various potential complications [16]. Computed tomography (CT) is widely used in clinical practice, and recent studies have illustrated that the use of an additional delayed acquisition with the patient in the supine and prone positions improves the diagnostic accuracy of CT in the diagnosis of LAA thrombosis [17]. However, delayed scanning increases the radiation dose, which is undesirable. Scanning in the prone position is also attractive due to its high diagnostic accuracy [18]. To date, no studies have investigated this novel method of body scanning in the left lateral position.

In this study, we analyzed the efficacy of left lateral decubitus CT for diagnosing LAA thrombus as a screening tool before catheter ablation and evaluated the risk factors for thrombus formation and thromboembolism complications.

We retrospectively analyzed the data of 101 patients diagnosed with AF who were admitted to our institution between May 2021 and January 2022. All the patients underwent transthoracic echocardiography (TTE) and left lateral decubitus cardiac CT. TEE was provided only to confirm the LAA thrombus. The exclusion criteria for CT were as follows: allergic reactions to iodide, increased creatinine levels, thyroid disease (hyperthyroidism), pregnancy, and age < 18 years. The CHA₂-DS₂-VASc and HAS-BLED scores were calculated in each patient. Our institutional ethics committee (JSC: National Scientific Cardiac Surgery Center, Local Bioethics Committee) approved this study, and it was conducted following the Declaration of Helsinki. All the patients provided written informed consent.

Transthoracic and transesophageal echocardiography

TEE was performed using a Phillips iE33 (Philips Medical Systems, USA) device to exclude LAA thrombus. TTE was performed using a Phillips EPIQ7 (Philips Medical Systems, USA) with the assessment of left ventricular (LV) function (LV ejection fraction), valve apparatus, and LV end-systolic and -diastolic volumes.

Computed tomography

CT scanning was performed on a Siemens Somatom Definition 64 device with retrospective cardiosynchronization and reconstruction with a slice thickness of 0.6 mm and a pitch of 0.2 mm. We placed the patients in the left lateral decubitus position with intravenous contrast bolus injection employing an Ohio Tandem automatic bolus-free CT injector at 5 ml/s, followed by the introduction of 70 ml saline solution. The scan was performed with “bolus tracking” on the aortic arch at 140 units. At the start of scanning the aortic arch, the delay after contrast introduction was 10 s. The patients were fitted with an electrocardiogram synchronizer. The contrast agent dose was calculated based on the patient’s weight. Two experienced cardiologists analyzed the TEE, and two experienced radiologists performed the CT angiography data analysis. Uniform filling of the LAA was regarded as normal. A defect in LAA filling was regarded as a blood clot. The LA anteroposterior and transverse dimensions were measured, and the LAA morphological structure was assessed. The LAA morphology was classified into four categories: 1 is a chicken wing; 2 is a windsock; 3 is a cauliflower; and 4 is a cactus (Fig. 1a, 1b, 1c, 1d). The LA volume was measured on the Syngo Via workstation using the volume application along the LA’s inner contour, including the LAA manually in each slice. Figure 2 shows an image of the LA volume calculation. Figure 3 illustrates the LAA thrombus detected by CT, and Fig. 4A and 4B demonstrates the LA dimensions as measured by CT.

CHA₂-DS₂-VASc and HAS-BLED scores

Stroke and bleeding risks were assessed using the CHA2DS2-VASc and HAS-BLED scores. At least one point is given for each of the following conditions: history of hypertension, diabetes, congestive heart failure, cardiovascular disease, stroke or transient ischemic attack, or female gender.

Hypertension (uncontrolled systolic blood pressure > 160 mmHg), abnormal renal and/or liver function, previous stroke, bleeding history or predisposition, labile international normalized ratios, elderly, and concomitant drugs and/or alcohol excess are all included in the acronym HAS-BLED, and each is assigned a point.

Statistical analysis

All the data were analyzed using statistical software STATA 16.0. The presence or absence of LAA thrombus was considered an outcome. For the bivariate analysis, simple logistic regression was used. The unadjusted odds ratios were presented to show the influence of sociodemographic and medical characteristics on the outcome. If the assumptions for performing logistic regression were not met, a non-parametric Fisher’s exact test was used. The significance level was set at 0.05.

A total of 101 patients were enrolled. The patients’ mean age was 60 years, ranging from 25 to 81 years. The men represented 54.5% of the patients, and the mean body mass index was 30 kg/m². The mean CHA2DS2-VASc score was 2, ranging from 0 to 5, and the mean HAS-BLED score was 0.9, ranging from 0 to 5. The average LA volume measured by cardiac CT was 120.2 cm³. The patients’ clinical and demographic characteristics are shown in Table 1.

Table 1

Patients’ demographic and medical characteristics (n = 101)
	Total (n = 101)	Women (n = 47, 47%)	Men (n = 54, 53%)
Age, years	60 \(\pm\)11	62\(\pm\)9	58\(\pm\)11
BMI, kg/m²	30\(\pm\)6	31\(\pm\)6	29\(\pm\)6
CHA₂DS₂-VASc score	2\(\pm\)1	2\(\pm\)1	1\(\pm\)1
HAS-BLED score	0.9\(\pm\)0.8	0.8\(\pm\)0.8	0.9\(\pm\)1
Coagulogram indicators
PT, s	13.8\(\pm\)5.5	13.6\(\pm\)4.6	14\(\pm\)6.3
INR, s	1.2\(\pm\)0.52	1.9\(\pm\)0.4	1.2\(\pm\)0.6
Fibrinogen, g/L	3.2\(\pm\)0.7	3.31\(\pm\)0.6	3.12\(\pm\)0.7
APTT, s	39\(\pm\)9	39.3 \(\pm\)10	38.7\(\pm\)7.9
Echocardiography indicators
ESD, cm	3.5\(\pm\)0.6	3.2\(\pm\)0.5	3.7\(\pm\)0.6
EDD, cm	4.5\(\pm\)0.7	4.2\(\pm\)0.6	4.8\(\pm\)0.6
ESV, mL	44.2\(\pm\)21	37.6\(\pm\)14.5	50\(\pm\)24
EDV, mL	100.4\(\pm\)37	87.8\(\pm\)28	111.3\(\pm\)40
SV, mL	54.5\(\pm\)15	50 \(\pm\)13.6	58.5 \(\pm\)15
LVEF, %	56.4\(\pm\)8.2	57.8\(\pm\)6.5	55.2\(\pm\)9.3
LVESVI, mL/m	23.2\(\pm\)11	20.7\(\pm\)7.5	25.3\(\pm\)13
LVEDVI, mL/m	52.4\(\pm\)18.8	48.2\(\pm\)13.9	56.1\(\pm\)21.7
CT of the heart
LA volume, cm³	120.2\(\pm\)33.9	118\(\pm\)34.6	122.1\(\pm\)33.4
LA shape
Cauliflower	29 (29%)	13 (28%)	16 (30%)
Chicken wing	18 (17%)	14 (30%)	4 (7%)
Windsock	29 (29%)	10 (21%)	19 (35%)
Cactus	25 (25%)	10 (21%)	15 (28%)
Anteroposterior size of the left atrium, cm	4.49\(\pm\)0.87	4.5\(\pm\)0.89	4.49\(\pm\)0.85
Transverse dimension of the left atrium, cm	7.2\(\pm\)0.95	7.1\(\pm\)0.92	7.54\(\pm\)0.9
Values are presented as mean ± SD or as n (%).
Abbreviations: APTT, activated partial thromboplastin time; BMI, body mass index; CT, computed tomography; EDD, end-diastolic dimension; EDV, end-diastolic volume; ESD, end-systolic dimension; ESV, end-systolic volume; LVESVI, left ventricular end-systolic volume index; LVEDVI, left ventricular end-diastolic volume index; SV, stroke volume; LVEF, left ventricular ejection fraction; index INR, international normalized ratio; LA, left atrium; PT, prothrombin time; TTE, transthoracic echocardiography

Higher CHA2-DS2-VASc and HAS-BLED scores and an enlarged LA and LA anteroposterior dimension were significantly associated with LAA thrombus (P < 0.05). An LAA cauliflower shape was also a predictor of LAA thrombus (P < 0.001). Multivariate logistic regression showed that an increase in the CHA2DS2-VASc score by 1 point increased the risk of LAA thrombus by five times (P < 0.001) (Table 2); an increase in the HAS-BLED score by 1 point increased the risk of blood clot formation by two times (P = 0.044); and an increase in LAA volume by 1 cm³ increased the risk of LAA thrombus by 2% (P = 0.019). An increase in the LAA anteroposterior size by 1 cm raised the risk of LAA thrombus by 2.9 times (P = 0.020) (Table 2).

Table 2

Association between sociodemographic and medical characteristics with LAA thrombus (n = 101)
	No LAA thrombus (n = 92, 91%)	LAA thrombus (n = 9, 9%)	OR (95% CI)*	p-value
Age, years (mean sd)	60\(\pm\)11	65\(\pm\)8	1.06 (0.98; 1.15)	0.148
BMI, kg/m²	30.2\(\pm\)5.9	30.04\(\pm\)4.2	0.99 (0.88; 1.12)	0.927
CHA₂DS₂-VASc score	1.36\(\pm\)1.12	3.67 \(\pm\)0.87	5.05 (2.09; 12.2)	< 0.001
HAS-BLED score	0.8\(\pm\)0.9	1.4\(\pm\)0.7	2.06 (1.02; 4.18)	0.044
Coagulogram indicators
PT, s	13.5\(\pm\)5.5	16.3\(\pm\)5.2	1.06 (0.97; 1.15)	0.199
INR, s	1.19\(\pm\)0.52	1.39\(\pm\)0.47	1.65 (0.66; 4.12)	0.287
Fibrinogen, g/L	3.23\(\pm\)0.7	3.05\(\pm\)0.9	0.69 (0.26; 1.88)	0.476
APTT, s	38.9\(\pm\)9.1	39.4\(\pm\)8.6	1.01 (0.93; 1.08)	0.870
Echocardiography indicators
ESD, cm	3.47\(\pm\)0.62	3.56\(\pm\)0.65	1.25 (0.42; 3.69)	0.690
EDD, cm	4.49\(\pm\)0.67	4.69\(\pm\)0.57	1.56 (0.56; 4.31)	0.393
ESV, mL	44.6\(\pm\)21.7	40.7\(\pm\)12.3	0.98 (0.95; 1.03)	0.594
EDV, mL	99.7\(\pm\)37.1	106.7\(\pm\)34.03	1.01 (0.99; 1.02)	0.589
SV, mL	54.1\(\pm\) 13.8	58.7\(\pm\)24.5	1.02(0.98; 1.07)	0.379
LVEF, %	56.5\(\pm\)8.2	55.6\(\pm\)8.9	0.99 (0.91; 1.07)	0.746
LVESVI, mL/m	23.3\(\pm\)11.5	21.3\(\pm\)4.3	0.98 (0.91; 1.06)	0.589
LVEDVI, mL/m	52.1\(\pm\)19.4	55.5\(\pm\)11.4	1.01 (0.98; 1.04)	0.613
CT of the heart
LA volume, cm³	117.6\(\pm\)33.3	147.3\(\pm\)28.6	1.02 (1.01; 1.04)	0.019
LA shape
Cactus	25 (27%)	0		0.068**
Cauliflower**	21 (23%)	8 (89%)		< 0.001**
Chicken wing	18 (20%)	0		0.157**
Windsock	28 (30%)	1 (11%)		0.207**
Anteroposterior size of the left atrium, cm	4.43\(\pm\)0.82	5.52\(\pm\)1.09	2.94 (1.18; 7.28)	0.020
Transverse dimension of the left atrium, cm	7.31\(\pm\)0.97	7.5\(\pm\)0.72	1.25 (0.59; 2.63)	0.565
*Unadjusted rates
** Fisher’s exact test
Values are presented as mean ± SD or as n (%).
Abbreviations: APTT, activated partial thromboplastin time; BMI, body mass index; CT, computed tomography; EDD, end-diastolic dimension; EDV, end-diastolic volume; ESD, end-systolic dimension; ESV, end-systolic volume; LVESVI, left ventricular end-systolic volume index; LVEDVI, left ventricular end-diastolic volume index; SV, stroke volume; LVEF, left ventricular ejection fraction; index INR, international normalized ratio; LA, left atrium; OR, odds ratio; PT, prothrombin time; TTE, transthoracic echocardiography

A history of hypertension was found in 76% of the participants, and a history of atherosclerosis was found in 58% of the patients. Diabetes mellitus was found in 11 patients, and the number of patients with low LV fraction was 14 (14%). Seven patients had a history of cerebrovascular accident before being admitted to the hospital. The patients’ comorbidities are illustrated in Table 3. Diabetes mellitus was significantly associated with the presence of LAA thrombus (P = 0.003) (Table 4).

Table 3

Patients’ comorbidities (n = 101)
	Total (n = 101)	Female (n = 47, 47%)	Male (n = 54, 53%)
Arterial hypertension
Yes	77 (76%)	39 (83%)	38 (70%)
No	24 (24%)	8 (17%)	16 (30%)
Coronary atherosclerosis
Yes	59 (58%)	26 (55%)	33 (61%)
No	42 (42%)	21 (45%)	21 (39%)
Diabetes
Yes	11 (11%)	7 (15%)	4 (7%)
No	90 (89%)	40 (85%)	50 (93%)
Heart failure
LVEF ≤ 39%	3 (3%)	0	4 (5.6%)
40 ≤ LVEF ≤ 49%	11 (11%)	5 (10.6%)	6 (11%)
LVEF ≥ 50%	87 (86%)	42 (89.4%)	45 (83.4%)
Assessment of heart valves
Normal	76 (75%)	33 (70%)	43 (79.6%)
Mitral valve	25 (25%)	14 (30%)	11 (20.4%)
Fibrillation form
Paroxysmal	37 (37%)	17 (36%)	20 (37%)
Persistent	50 (49%)	23 (49%)	27 (50%)
Long-term persistent	12 (12%)	5 (11%)	7 (13%)
Constant	2 (2%)	2 (4%)	0
Abbreviations: LVEF, left ventricular ejection fraction

Table 4

Association between comorbid conditions and LAA thrombus (n = 101)
	No LAA thrombus (n = 92, 91%)	LAA thrombus (n = 9, 9%)	OR (95% CI)*	p-value
Arterial hypertension
No	22 (24%)	2 (22%)	ref
Yes	70 (76%)	7 (78%)	1.1 (0.21; 5.69)	0.909
Coronary atherosclerosis
No	38 (41%)	4 (44%)	ref
Yes	54 (59%)	5 (56%)	0.88 (0.22; 3.49)	0.856
Diabetes
No	85 (92%)	5 (56%)	ref
Yes	7 (8%)	4 (44%)	9.71 (2.12; 44.6)	0.003
Heart failure
LVEF ≤ 39%	2 (2%)	1 (11%)
40 ≤ LVEF ≤ 49%	11 (12%)	0
LVEF ≥ 50%	79 (86%)	8 (89%)
Assessment of heart valves
Normal	71 (77%)	5 (56%)	ref
Mitral valve	21 (23%)	4 (44%)	2.7 (0.67; 10.9)	0.164
Fibrillation form
Paroxysmal	35 (38%)	2 (22%)
Persistent	46 (50%)	4 (45%)
Long-term persistent	10 (11%)	2 (22%)
Constant	1 (1%)	1 (11%)
*Unadjusted rates
** Fisher’s exact test
Values are presented as mean ± SD or as n (%).
Abbreviations: APTT, activated partial thromboplastin time; CT, computed tomography; EDD, end-diastolic dimension; EDV, end-diastolic volume; ESD, end-systolic dimension; ESV, end-systolic volume; LVESVI, left ventricular end-systolic volume index; LVEDVI, left ventricular end-diastolic volume index; LVEF, left ventricular ejection fraction; index INR, international normalized ratio; LA, left atrium; OR, odds ratio; PT, prothrombin time; TTE, transthoracic echocardiography

An increase in the CHA2DS2-VASc score by 1 point raised the risk of thromboembolism and cerebral infarct by 12%. An increase in LAA volume by 1 cm³ and in the LA anteroposterior dimension increased the risk of acute cerebral infarct by 2% and 78%, respectively (Table 5). The association between comorbid conditions and an acute cerebrovascular accident is shown in Table 6.

Table 5

Association between sociodemographic and medical characteristics with acute cerebrovascular accident (CVA) (n = 101)
	Without CVA (n = 94, 93%)	With CVA (n = 7, 7%)	OR (95% CI)*	p-value
Age, years (mean sd)	60\(\pm\)11	59\(\pm\)6	0.99 (0.93; 1.07)	0.88
BMI, kg/m²	30 \(\pm\)5.8	31.5\(\pm\)5.3	1.04 (0.92; 1.19)	0.522
CHA₂DS₂-VASc score	1.37\(\pm\)1.22	2.86\(\pm\)1.46	1.12 (1.18; 3.81)	0.012
HAS-BLED score	0.86\(\pm\)0.89	0.86\(\pm\)0.69	0.99 (0.41; 2.41)	0.989
Coagulogram indicators
PT, s	13.6\(\pm\)5.58	15.9\(\pm\)4.7	1.04 (0.95; 1.15)	0.349
INR, s	1.19\(\pm\)0.52	1.39\(\pm\)0.44	1.59 (0.59; 4.31)	0.363
Fibrinogen, g/L	3.23\(\pm\)0.67	2.6\(\pm\)0.85	0.23 (0.06; 0.84)	0.026
APTT, s	38.4\(\pm\)8.6	47.1\(\pm\)11.6	1.08 (1.01; 1.15)	0.024
Echocardiography indicators
ESD, cm	3.47\(\pm\) 0.63	3.53\(\pm\)0.53	1.15 (0.34; 3.93)	0.82
EDD, cm	4.51\(\pm\)0.68	4.57\(\pm\)0.48	1.16 (0.36; 3.7)	0.80
ESV, mL	44.2\(\pm\)21.3	44.6\(\pm\)17.5	1.0 (0.97; 1.04)	0.964
EDV, mL	100.6\(\pm\)37.3	97.3\(\pm\)30.3	0.99 (0.97; 1.02)	0.818
SV, mL	54.6\(\pm\)14.9	52.7\(\pm\)16.5	0.99 (0.94; 1.05)	0.742
LVEF, %	56.6\(\pm\)8.3	54.3\(\pm\)7.3	0.97 (0.89; 1.05)	0.479
LVESVI, mL/m	23.2\(\pm\)11.2	23.2\(\pm\)8.6	1.0 (0.93; 1.07)	0.992
LVEDVI, mL/m	52.5\(\pm\)19.1	50.9\(\pm\)14.8	0.99 (0.95; 1.04)	0.819
CT of the heart
LA volume, cm³	118.3\(\pm\)34	146.1\(\pm\)18.8	1.02 (1.01; 1.04)	0.046
LA shape
Cauliflower	25 (27%)	4 (57%)		0.102**
Chicken wing	18 (19%)	0		0.241**
Windsock	27 (29%)	2 (29%)		0.679**
Cactus	24 (25%)	1 (14%)		0.445**
Anteroposterior size of the left atrium, cm	4.45\(\pm\)0.8	5.16\(\pm\)0.9	1.78 (1.03; 7.49)	0.044
Transverse dimension of the left atrium, cm	7.29\(\pm\)0.96	7.84\(\pm\)0.71	2.0 (0.79; 5.01)	0.138
*Unadjusted rates
Values are presented as mean ± SD or as n (%).
Abbreviations: APTT, activated partial thromboplastin time; CT, computed tomography; EDD, end-diastolic dimension; EDV, end-diastolic volume; ESD, end-systolic dimension; ESV, end-systolic volume; LVESVI, left ventricular end-systolic volume index; LVEDVI, left ventricular end-diastolic volume index; SV, stroke volume; LVEF, left ventricular ejection fraction; index INR, international normalized ratio; LA, left atrium; OR, odds ratio; PT, prothrombin time; TTE, transthoracic echocardiography

Table 6

Association between comorbid conditions and acute cerebrovascular accident (CVA) (n = 101)
	Without CVA (n = 94, 93%)	With CVA (n = 7, 7%)	OR (95% CI)*	p-value
Arterial hypertension
No	23 (24%)	1 (14%)	ref
Yes	71 (76%)	6 (86%)	1.94 (0.22; 16.9)	0.548
Coronary atherosclerosis
No	39 (41%)	3 (43%)	ref
Yes	55 (59%)	4 (57%)	0.95 (0.2; 4.46)	0.944
Diabetes
No	83 (88%)	7 (100%)
Yes	11 (12%)	0
Heart failure
LVEF ≤ 39%	3 (3%)	0
40 ≤ LVEF ≤ 49%	10 (11%)	1 (14%)
LVEF ≥ 50%	81 (86%)	6 (86%)
Assessment of heart valves
Normal	72 (77%)	4 (57%)	ref
Mitral valve	22 (23%)	3 (43%)	2.45 (0.51; 11.8)	0.263
Fibrillation form
Paroxysmal	36 (38%)	1 (14%)
Persistent	47 (50%)	3 (43%)
Long-term persistent	10 (11%)	2 (29%)
Constant	1 (1%)	1 (14%)
*Unadjusted rates
Abbreviations: LVEF, left ventricular ejection fraction; OR, odds ratio

In this study, we found that scanning the patient in the left lateral decubitus position to be more physiological because the LAA assumes a vertical position and contrast filling improves.

All the LAA thrombi detected on CT were confirmed on TEE. When scanning in the supine position, the LAA lies on a horizontal plane, and in some cases, a repeated LAA acquisition is required, which leads to an increased radiation dose. One case report of cryoballoon ablation used the left lateral decubitus position in AF in which the LA was compressed by the vertebra; the left lateral cardiac СT demonstrated that the heart can shift forward, and in the left lateral decubitus posture, compression of the LA can be eased [19].

Although used in most guidelines for risk stratification [20, 21, 22], we found that the CHA2DS2-VASc stroke score was significantly associated with the presence of LAA thrombus and correlated with cerebrovascular accidents.

Oral anticoagulation is generally successful in reducing these embolic dangers, and it is commonly advised for patients with AF who are at high risk. On the other hand, anticoagulation treatment is strongly associated with an increased risk of bleeding. The HAS-BLED score is widely used in clinical guidelines for predicting bleeding risk [23]. We found that the HAS-BLED score was significantly associated with LAA thrombus. LV ejection fraction was not significantly associated with the presence of LAA thrombus. This result is most likely due to the fact that the proportion of patients with heart failure was low; in most of the patients, the ejection fraction was high. LA volume is an independent risk factor for various cardiovascular events, associated with coronary sclerosis and an increased risk of ischemic stroke and myocardial infarction [24, 25]. An increase in the LA volume is frequently associated with an AF relapse after radiofrequency ablation [26]. An enlarged LA and an increased LA anteroposterior dimension as measured by CT were strongly associated with LAA thrombus. Diabetes mellitus and AF are thought to have comparable thrombosis mechanistic routes [27]. In our research, diabetes mellitus was significantly associated with the presence of LAA thrombus. LAA morphology can be quantified using echocardiography, CT, or cardiac magnetic resonance imaging [28]. Four types of LAA morphology were obtained using CT: (1) chicken wing, (2) windsock, (3) cauliflower, and (4) cactus. A recent meta-analysis found that non-chicken wing morphology was mainly associated with LAA thrombosis and thromboembolic events [29]. In our study, LAA cauliflower morphology was strongly associated with the presence of LAA thrombus and a higher incidence of thromboembolic complications.

Our study has several limitations. First, it was a single-center study, and to our knowledge, no previous investigations had described LA filling with contrast in the left lateral position. Furthermore, although the present analysis included 101 patients, there are still limitations in the patient sample due to their relatively young age. Second, in our center, measurements of the linear dimensions and volumes of the LV were performed only on TTE. Given that the echocardiograms were gathered from hospital records in the research location, they were not interpreted systematically; nonetheless, these data reflect actual clinical practice. Finally, CT with the evaluation of the LA anteroposterior dimension was obtained by measuring on the left lateral decubitus plane, which could need correction, although LA volume does not alter despite a change in body position.

Our findings showed that cardiac CT with the patient positioned on the left side is a useful screening tool to determine LAA thrombus. Moreover, it can be used to determine the various risk factors of LAA thrombus formation and cerebrovascular events.

atrial fibrillation

APTT

activated partial thromboplastin time

BMI

body mass index

computed tomography

EDD

end-diastolic dimension

ESD

end-systolic dimension

EDV

end-diastolic volume

ESV

end-systolic volume

INR

international normalized ratio

left atrium

LAA

left atrium appendage

Left ventricular

LVEDVI

left ventricular end-diastolic volume index

stroke volume

LVEF

left ventricular ejection fraction

LVESVI

left ventricular end-systolic volume index

odds ratio

prothrombin time

TEE

transesophageal cardiography

TTE

transthoracic echocardiography

Ethics approval and consent to participate

Our institutional ethics committee approved this study and it was conducted following the Declaration of Helsinki. All patients included provided written informed consent.

Consent to publish

Not applicable

Availability of data and materials

The data underlying this article will be shared on reasonable request to the corresponding author.

Conflicts of interest statement

The authors declare that they have no conflicts of interest.

Funding

This study did not receive any funding

Acknowledgements

I would like to thank Dr. Marat Aripov for his invaluable assistance and insights leading to the writing of this paper.

Author Contributions

Tairkhan Dautov: Conceptualization, Methodology

Bauyrzhan Kaliyev: Data curation, Writing- Original draft preparation Lyazzat Bastarbekova, Zhanar Moldakahnova: Visualization Investigation. Raushan Rakhimzhanova: Supervision Azhar Kabdullina: Validation

Almas Bimakhan, Umida Ismailova :Writing- Reviewing and Editing.

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No competing interests reported.

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Novel thrombosis diagnostic strategies: left lateral decubitus computed tomography before catheter ablation in patients with atrial fibrillation

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Abstract

Background

Methods

Results

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Background

Methods

Transthoracic and transesophageal echocardiography

Computed tomography

CHA₂-DS₂-VASc and HAS-BLED scores

Statistical analysis

Results

Discussion

Conclusions

Abbreviations

Declarations

References

Additional Declarations

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