Blood flow analysis with computational fluid dynamics in the left atrium after left atrial plication: a prospective study

OBJECTIVE

This study aimed to evaluate blood flow stagnation in an enlarged left atrium (LA) and prove that left atrial plication (LAP) could alleviate the stagnation.

METHODS

Five patients with chronic atrial fibrillation who underwent mitral valve surgery followed by LAP for an enlarged LA with a ≥ 60-mm diameter were included. We performed computational fluid dynamics (CFD) analysis using preoperative and postoperative computed tomography and four-dimensional flow magnetic resonance imaging. Additionally, computer graphics were used to create virtual left atrial appendage resection (LAAR) images. We performed CFD analysis to assess blood flow stagnation in the LA for three groups: preoperative, LAAR, and LAP.

RESULTS

When the average and constant stagnation volumes were both set to 100 preoperatively, the average stagnation volumes of the LAAR and LAP groups were 67.42 ± 18.64 and 35.88 ± 8.20, respectively. The constant stagnation volumes of these groups reduced to 45.01 ± 7.43 and 21.14 ± 7.70, respectively. The LAP group also had significantly lower average and constant stagnation volumes than those in the LAAR group (p = 0.006 and p = 0.033, respectively).

CONCLUSIONS

Blood flow stagnation was noted in the LAA and enlarged LA. CFD analysis revealed that LAP for the enlarged LA improved blood flow stagnation more than the virtual LAAR alone.

CLINICAL TRIAL REGISTRY NUMBER

UMIN000049923.

Efficacy of left atrial plication for atrial functional mitral regurgitation

OBJECTIVE

Atrial functional mitral regurgitation (AFMR) is caused by atrial fibrillation and left atrial enlargement. Our study aimed to evaluate the efficacy of left atrial plication (LAP) for AFMR.

METHODS

Of 1164 mitral valve surgery patients at our hospital from January 2000 to May 2019, 22 patients underwent surgery for AFMR. Our retrospective analysis divided the patients with AFMR into two groups according to whether LAP was performed (LAP + group, n = 9; LAP - group, n = 13). Mitral valve angle (MV angle) (horizontal inclination of mitral valve) was measured by pre- and post-operative computed tomography scan. Individuals with type II mitral regurgitation, left ventricular ejection fraction of < 55%, males with left ventricular endo-diastolic dimension of > 60 mm and females with > 55 mm, aortic valve disease, mitral valve calcification, hypertrophic obstructive cardiomyopathy, and both "redo" and emergency cases were excluded.

RESULT

Mitral valve replacement was performed in 6 patients and mitral ring annuloplasty in 16 cases. No recurrence of mitral regurgitation or structural valve deterioration occurred during the follow-up period. There were no hospital deaths; 3 deaths occurred during the follow-up period. Compared to the LAP - group, the LAP + group demonstrated a significantly greater decrease of MV angle (16.6 ± 8.1° vs. 1.2 ± 6.9°, p < 0.01) and left atrial dimension (18.4 ± 7.0 mm vs. 6.9 ± 14.6 mm, p = 0.02).

CONCLUSIONS

Surgical results of AFMR were satisfactory. LAP may be appropriate for correcting the angle of a mitral valve tilted horizontally. More cases need to be considered in the future.