Cardiac Hemodynamics of Percutaneous Left Atrial Appendage Occlusion

Background
The management of atrial fibrillation is of importance in the prevention of thromboembolic events and stroke. Given the significant role of the left atrial appendage in regulation of elevated filling pressures in the left ventricle, percutaneous left atrial appendage occlusion (LAAO) devices are emerging as an alternative to anticoagulation for stroke prevention. Nevertheless, the effect of LAAO on cardiac hemodynamics have not been well characterized.

Methods
This is a retrospective study of 70 patients who underwent LAAO with the WATCHMAN device at a single center. All patients had a baseline pre-procedural transthoracic echocardiogram (TTE) as well as a post-procedural TTE within 15 months after the procedure. Patients who did not have a pre/post procedural TTE were excluded from the study. Hemodynamic and diastolic parameters were assessed through TTE and compared between the groups.

Results
Forty-two patients (mean age 71.8 ± 9.9 years) underwent LAAO in this study with baseline and follow-up TTE. The patients were predominantly male (73.8%) and had follow-up TTE within 15 months (35.6 ± 102.2 days). Patients were found to have a statistically significant increase in right ventricular systolic pressure (RVSP) (34.8 ± 4.1 vs 40.4 ± 4.1, p=0.04), mitral E wave velocity (0.97 ± 0.06 vs 1.09 ± 0.05, p=0.01), mitral E/e’ (16.3 ± 2.9 vs. 21.4 ± 3.9, p=0.002), and left ventricular ejection fraction (53.5 ± 2.0 vs. 56.3 ± 1.9, p=0.02) on follow up TTE when compared with pre-procedural values. No significant changes in left atrial volume indices or right ventricular diameters were noted.

Conclusions
Percutaneous LAAO via the WATCHMAN device results in cardiac hemodynamic changes that can be non-invasively quantified by TTE. LAAO revealed statistically significant elevation in RVSP and diastolic parameters such as mitral E/e’, which may be due to decreased LA volumes from LAAO and subsequent increases in left-sided filling pressures. In addition, LVEF minimally improved following LAAO. The impact of these hemodynamic changes on cardiac physiology and remodeling will need to be explored in future studies.