Retrospective Analysis of Left Atrial Enlargement after Surgical Left Atrial Appendage Amputation or Ligation

Objectives: Atrial fibrillation (AF) is a common cause of thromboembolic stroke. The left atrial appendage (LAA) is deemed to be the main source for stroke-causing thrombi, which is why the LAA has become a recently much noticed therapeutic target to prevent AF-caused stroke. Consequently, over the last few years LAA amputation or ligation concomitant to coronary artery bypass grafting (CABG) has become an increasingly performed technique in patients with AF or with a high CHA2DS2-VASc-Score if AF after cardiac surgery occurs. However, while the impact of LAA amputation or ligation on the left atrium has not yet been well understood, it has recently come under suspicion for itself causing atrial fibrillation due to left atrial dilation. To examine the hypothesis of left atrial dilation after LAA amputation or ligation, we retrospectively assessed the left atrial width and volume before and after LAA amputation or ligation in patients undergoing off-pump CABG.

Methods: The left atrium was assessed on the day of hospitalization and the 6^th‱10^th postoperative day by transthoracic echocardiography using the four-chamber view. Patients included showed no signs of mitral or tricuspid valve insufficiency or stenosis, no pulmonary hypertension and ranged in age from 30 to 80 years. Weight difference was less than 1.5 kg and blood pressure after Riva-Rocci difference was less than 30 mm Hg between the echocardiographic examinations. Furthermore, neither switch to on-pump surgery nor use of ECLS or IAPB occurred.

Results: Neither left atrial width nor left atrial volume changed significantly after LAA amputation or ligation. Subgroup analysis did not show any condition-dependent tendencies ([Table 1]).

Table 1 Impact on LA Width and Volume

	N	Preoperative	Postoperative	p-Value
LA Width [mm]	77	39.12	39.09	0.5951
LA Volume [mL]	77	45.52	44.91	0.9395

Conclusion: Surgical amputation or ligation of the left atrial appendage concomitant to CABG has no significant short-term impact on the left atrial volume. While in the short term no morphological changes occur, molecular analysis of potential impact on cardiac peptides has not been investigated yet. Therefore, further examination, prospective studies and long-term analysis of the suspected impact after cardiac surgical procedures with and without use of the heart-lung machine will determine the role of left atrial appendage amputation or ligation in cardiac surgery.