Association Between Left Atrial Appendage Morphology and Function and the Risk of Ischaemic Stroke in Patients with Atrial Fibrillation.

AF is the most common cardiac arrhythmia and has been identified as an independent risk factor for stroke. The European Society of Cardiology guidelines recommend a thromboembolic event risk assessment based on the CHA2DS2-VASc score. However, stroke also occurs in some patients with a low CHA2DS2-VASc score. Therefore, it is necessary to find new factors to improve thromboembolic risk stratification in AF patients. Over 90% of embolic strokes are caused by thrombi originating from the left atrial appendage (LAA). Thus, certain anatomical or functional parameters of the LAA could potentially be used to predict cardioembolic stroke. Studies have suggested that some of these factors, such as LAA morphology, number of LAA lobes, LAA dimensions, LAA volume, distance from the LAA ostium to the first bend of LAA, LAA orifice diameter, extent of LAA trabeculations, LAA takeoff, LAA flow velocity and LAA strain rate, are independently associated with a higher risk of stroke in a population of patients with AF and improve the performance of the CHA2DS2-VASc score. However, the results are conflicting and, so far, no new parameter has been added to the CHA2DS2-VASc score.

Association of Left Atrial Sphericity with Risk of Stroke in Patients with Atrial Fibrillation. Sub-Analysis of the ASSAM Study.

PURPOSE: The study was designed to evaluate the value of left atrial (LA) sphericity (LASP) in the identification of patients with atrial fibrillation (AF) who had prior ischemic stroke. The secondary aim was to investigate the possibility of improving stroke risk assessment based on six geometrical variables of LA. METHODS: This prospective observational study involved 157 patients: 74 in the stroke group and 83 in the control. All patients had cardiac computed tomography (CT) performed to analyze LA volume and dimensions. LASP and the discriminant function of six geometrical measurements were calculated. RESULTS: Multivariate logistic regression analysis showed a significant association of stroke with and gender, diabetes, CHA2DS2-VASc score, LA anteroposterior diameter, and LA sphericity. Patients with prior stroke had lower LASP than those without (66.6 ± 10.3% vs. 70.5 ± 7%; p = 0.0062). The most accurate identification of patients with a history of ischemic stroke was achieved by using a function of six geometrical measurements, the sphericity and volume coefficient. The C-statistic was higher for the above discriminant function (0.7273) than for LASP (0.3974). The addition of the discriminant function to the CHA2DS2-VASc score increased the performance of the risk score alone. CONCLUSION: LASP is associated with prior stroke in AF patients. The proposed new formula for identification of AF patients who are at risk of stroke, based on geometrical measurements of LA, is superior to the basic LASP in identification of AF patients with a history of stroke.

Assessment of the left atrial appendage morphology in patients after ischemic stroke - The ASSAM study.

BACKGROUND: The ASSAM study was designed to evaluate the association between left atrial appendage (LAA) morphology and stroke risk in patients with atrial fibrillation (AF). METHODS: The study included 85 randomly chosen AF patients with acute ischemic stroke matched with 84 AF without stroke. All patients had left atrial (LA) computed tomography performed to analyze LAA anatomy. RESULTS: Patients in the stroke group had a larger LAA volume (10.22 [7.83-13.62] vs. 9.33 cm3 [7.33-11.47], p = 0.046], greater distance from LAA ostium to the first LAA bend (9.25 ± 3.85 vs. 7.23 ± 2.95 mm, p = 0.0002), and more frequently had round LAA ostium shape (11.8 vs. 1.2%, p = 0.005). According to a multivariable model, significant predictors of ischemic stroke were distance from LAA ostium to the first LAA bend (OR 1.202 [1.065-1.356], p = 0.003), LAA ostium round shape of (OR 16.813 [1.857-152.231], p = 0.012), LAA ostium surface area (OR 0.612 [0.457-0.819], p = 0.009), and cactus LAA morphology (OR 2.739 [1.176-6.380], p = 0.016). After adjusting for CHA2DS2-VASc score, only the distance from LAA ostium to the first LAA bend remained a significant risk factor for stroke (OR 1.154 [1.014-1.314], p = 0.03). CONCLUSIONS: The distance from LAA ostium to the first bend of the LAA was independently associated with stroke risk in patients with AF. Whether this parameter may help improve identification of patients at risk of ischemic stroke, needs to be confirmed in larger studies.

Iatrogenic Arteriovenous Fistula and Atrial Septal Defect Following Cryoballoon Ablation for Atrial Fibrillation - Two Correctable Causes of Right Heart Failure.

BACKGROUND Catheter ablation for atrial fibrillation is an important therapeutic intervention. One of the most frequent complications of this procedure is vascular issues including arteriovenous fistula. Iatrogenic atrial septal defect (IASD) has been reported as a complication of transseptal puncture; however, no data are available demonstrating any coexistent of arteriovenous fistula with IASD. CASE REPORT A 61-year-old female patient was admitted to our center for catheter ablation for persistent atrial fibrillation. Her past medical history was significant for cryoballoon ablation for atrial fibrillation in 2015, which was subsequently complicated by hematoma and arteriovenous fistula at puncture site. After general surgery consultation, the patient was qualified for conservative treatment. To exclude left atrial thrombus before redo procedure, transesophageal echocardiography was performed which visualized the presence of 9-mm atrial septal defect with left-to-right shunting, detecting right-to-left shunting using Valsalva maneuver. No significant valvular abnormalities were identified. The next day, pulmonary vein isolation for atrial fibrillation was performed. One month later, a control transthoracic echocardiogram (TTE) revealed hemodynamic significant left-to-right shunting with Qp/Qs 2.0 and high probability of pulmonary hypertension. Vascular surgery for arteriovenous fistula was successfully performed in October 2018. Subsequent TTE, performed a month later, confirmed no left-to-right shunting and no signs of pulmonary hypertension or diminishment of the right atrium. CONCLUSIONS Vascular access during catheter ablation for atrial fibrillation may result in arteriovenous fistula. This condition might affect right atrium pressure leading to increased diameter of previous puncture site at the interatrial septum, causing IASD with significant shunting. In this group of patients, arteriovenous fistula should be treated as soon as possible.