Renin-angiotensin system inhibition is associated with reduced risk of left atrial appendage thrombosis formation in patients with atrial fibrillation.

BACKGROUND

Inhibition of the renin-angiotensin axis can reduce the likelihood of atrial fibrillation (AF). However, the effects of angiotensin-converting-enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) on thrombogenicity in AF remain incompletely elucidated. Thisretrospective case-control study was conducted to evaluate whether the use of ACEI or ARB could reduce the incidence of left atrial appendage thrombus (LAAT) and spontaneous echocardiographic contrast (SEC) in patients with AF.

METHODS

A total of 199 AF patients who received both transesophageal echocardiogram (TEE) and transthoracic echocardiogram (TTE) successively on the same day from 2012 to 2016 were enrolled. Left atrial dimension, maximal left atrial volume (LAVmax), left ventricular end-diastolic dimension, left ventricular ejection fraction, and the ratio of the early transmitral flow velocity and the early mitral annular velocity (E/e') were determined. Longitudinal LA strain was evaluated using two-dimensional speckle tracking imaging at each LA segment. Peak systolic strain was calculated by averaging total segments. LAAT, LAA emptying flow velocity (LAAeV) and SEC were evaluated by TEE. Risk factors for LAAT and usage of ACEIs or ARBs were recorded.

RESULTS

The incidence of LAAT was 27.6%. Among the patients with renin-angiotensin system (RAS) inhibitors, 20.5% were demonstrated to have LAAT, compared with 33.3% in the nonuser group (p = 0.044). LA peak systolic strain and LAAeV were significantly increased in patients with RAS inhibitors compared to the nonuser group (p = 0.002, p = 0.047, respectively). Patients with LAAT had higher CHA2DS2-VASc scores and evident SEC compared with those without LAAT (p = 0.000, p = 0.000, respectively). Usage of ACEIs/ARBs and antiplatelet drugs were frequent in patients with LAAT than in those without LAAT (p = 0.044, p = 0.000, respectively). Even after controlling for LAAT-related risk factors (age, body mass index, AF type, hypertension, diabetes mellitus, prior stroke or transient ischemic attack, drinking history and usage of antiplatelet drugs and LAVmax), use of RAS inhibitors remained significantly associated with a lower risk of LAAT (OR = 0.222; 95% CI 0.084-0.585, p = 0.002).

CONCLUSIONS

This study shows that RAS inhibitors may be effective in reducing the risk of LAAT in patients with AF through atrial reverse remodeling.