Left Atrial Flow Stasis in Patients Undergoing Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation Using 4D-Flow Magnetic Resonance Imaging

Abstract

Atrial fibrillation (AF) is associated with systemic thrombo-embolism and stroke events, which do not appear significantly reduced following successful pulmonary vein (PV) ablation. Prior studies supported that thrombus formation is associated with left atrial (LA) flow alterations, particularly flow stasis. Recently, time-resolved three-dimensional phase-contrast (4D-flow) showed the ability to quantify LA stasis. This study aims to demonstrate that LA stasis, derived from 4D-flow, is a useful biomarker of LA recovery in patients with AF. Our hypothesis is that LA recovery will be associated with a reduction in LA stasis. We recruited 148 subjects with paroxysmal AF (40 following 3–4 months PV ablation and 108 pre-PV ablation) and 24 controls (CTL). All subjects underwent a cardiac magnetic resonance imaging (MRI) exam, inclusive of 4D-flow. LA was isolated within the 4D-flow dataset to constrain stasis maps. Control mean LA stasis was lower than in the pre-ablation cohort (30 ± 12% vs. 47 ± 18%, p < 0.001). In addition, mean LA stasis was reduced in the post-ablation cohort compared with pre-ablation (36 ± 15% vs. 47 ± 18%, p = 0.002). This study demonstrated that 4D flow-derived LA stasis mapping is clinically relevant and revealed stasis changes in the LA body pre- and post-pulmonary vein ablation.

The Minimum Number of Ablation Lines for Complete Isolation of the Pulmonary Veins during Thoracoscopic Ablation for Atrial Fibrillation

“…AF often shows no definite symptoms. However, it can result in significant complications, such as thromboembolism [ 25 ]. The treatments for converting AF to sinus rhythm include cardioversion, pharmacologic control, catheter ablation, and surgical treatment.…”

Left atrium 4D-flow segmentation with high-resolution contrast-enhanced magnetic resonance angiography

“…Furthermore, phase-contrast cardiovascular magnetic resonance (CMR) with flow-encoding in all three spatial directions (4D-flow) provides 3D blood velocity information in 3D volume throughout the cardiac cycle ( 9 – 11 ). With its power of visualization and quantification, this technique opened new horizons in understanding cardiovascular flow and has been used to assess flow patterns and parameters, including velocity, stasis, and vorticity in LA and LAA in patients with AF ( 12 – 22 ). However, the segmentation of heart chambers is challenging because of the limited resolution and contrast of the 4D-flow.…”

“…In addition, during 4D-flow acquisition after routine measurements, wash-out of the contrast agent further reduces the contrast of 4D-flow. Thus, most previous 4D-flow studies in AF patients relied upon manual segmentation on magnitude image ( 13 , 20 ) or phase-contrast magnetic resonance angiography (PC-MRA) ( 12 , 13 , 15 , 16 , 18 , 21 , 22 ), which is time-consuming, depends on the operator's knowledge and experience, and has limited reproducibility ( 20 ). An interesting approach was 4D-flow co-registration with the cine images ( 19 ).…”

Image Processing and Analysis for Preclinical and Clinical Applications

“…Among the other research papers, four of them focus on biomedical image quantification, including the early monitoring response to therapy in patients with brain lesions [17], the quantification of cancer cell mass evolution in zebrafish [18], the clinical comparison of the glomerular filtration rate calculated from different renal depths and formulae [19], and the assessment of the left atrial flow stasis in patients undergoing pulmonary vein isolation for paroxysmal atrial fibrillation [20].…”

“…In [20], the authors aimed to demonstrate that left atrial (LA) stasis, derived from 4D-flow, is a useful biomarker of LA recovery in patients with atrial fibrillation (AF). AF is associated with systemic thrombo-embolism and stroke events, which do not appear significantly reduced following successful pulmonary vein (PV) ablation.…”