The Left Atrial Appendage Revised

Abstract

Nonvalvular atrial fibrillation is associated with a 4- to 5-fold strokes increase and may be responsible for 15% to 20% of all strokes in the elderly. In this scenario, the left atrial appendage thrombus would be the associated with 90% of cases. The use of anticoagulants, percutaneous devices, and the left atrial appendage surgical exclusion is still an open discussion. For left atrial appendage procedures, relevant anatomic spatial relationships have to be emphasized, besides the chance of the normal physiological functioning would be eliminated with the proceedings. There are evidences that the left atrial appendage closure during routine cardiac surgery is significantly associated with an increased risk of early postoperative atrial fibrillation. Therefore, the purpose of this review is to focus basic aspects for continuous medical education. In summary, the rationale of this text is to emphasize anatomical and pharmacological aspects involved in the simple surgical exclusion of left atrial appendage under cardiopulmonary bypass. There are several operative techniques, but to conclude this revision it will present one of them based on the discussed basic sciences.

The Effect of Minimally Invasive Thoracoscopic Left Atrial Appendage Excision on Cardiac Dynamic and Endocrine Function

“…A series of studies have demonstrated that prolonged AF results in the loss of effective atrial contraction and atrioventricular synchrony. 2 , 6 , 7 , 21 – 23) In this prospective, self-controlled study, we evaluated left atrial volume and left atrial hemodynamic performance by real-time three-dimensional echocardiography. The LA size at baseline was obviously beyond the cutoff of 35 mm for the enrolled AF patients.…”

“…Moreover, several studies have shown that the LAA is largely involved in ANP secretion and plays an important role in body fluid modulation. 7 , 11) In a clinical study, Yoshihara et al 27) demonstrated that ANP secretion was attenuated in the early postoperative period after the Maze procedure, including bilateral atrial appendectomy, and it persisted in the chronic phrase. Concurrently, this attenuated ANP directly affects body fluid balance during the early postoperative period.…”

“… 3 – 6) Specifically, the advances in widely adapted catheter ablation technologies have not converted to significant gains in success rates over recent years. 7) It is however important to note that stroke is the most dreaded complication for each AF patient. Therefore, selection of the best strategy aiming at lowering the risk of embolic events is becoming more problematic.…”

Left Atrial Appendage: Anatomy, Function, and Importance in Thrombus Formation

“…Além disso, o apêndice possui a maior concentração de grânulos de peptídeo natriurético atrial (PNA) do AE 22 (cerca de 30%). 4,23 O estímulo para secreção de PNA é a distensão dos cardiomiócitos, e, por ser mais complacente e concentrar a maior quantidade de PNA, o AAE é mais sensível às variações de volume e pressão e exerce maior controle sobre a redução da pressão arterial e aumento da frequência cardíaca, diurese e natriurese. 4,23,24 O AAE realiza contração ativa, 4 e sua velocidade de fluxo pode ser quantificada pelo Doppler pulsátil.…”

“…4,23 O estímulo para secreção de PNA é a distensão dos cardiomiócitos, e, por ser mais complacente e concentrar a maior quantidade de PNA, o AAE é mais sensível às variações de volume e pressão e exerce maior controle sobre a redução da pressão arterial e aumento da frequência cardíaca, diurese e natriurese. 4,23,24 O AAE realiza contração ativa, 4 e sua velocidade de fluxo pode ser quantificada pelo Doppler pulsátil. Na maioria dos pacientes submetidos ao ecocardiograma transesofágico (ECO-TE), esse fluxo é quadrifásico 4,25,26 (Figura 2).…”