- Left atrial appendage closure (LAAC) is an alternative approach to anticoagulation therapy to prevent ischemic cerebrovascular accidents (CVA) associated with atrial fibrillation (AF)
- Analysis of postoperative mortality and CVA rates supports concomitant prophylactic surgical LAAC
- Concomitant surgical LAAC confers reduced CVA risk particularly for those with preoperative AF
Ischemic cerebrovascular accident (CVA), a stroke due to obstructed blood flow, is a complication of Atrial fibrillation (AF) and is responsible for a significant proportion of morbidity and mortality in the general population over 65 years of age. The pathophysiology begins with arrhythmia, which impedes the flow of blood through the heart, leading to the formation of thromboembolisms. The specific anatomical source of the embolism is often the left atrial appendage (LAA). Thromboembolisms forming in the LAA during arrhythmia may then eventually travel to the brain causing ischemic CVA.
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The standard treatment for patients with AF is oral anticoagulant therapy. However, some patients are then at risk for equally devastating hemorrhagic CVA. Left atrial appendage closure (LAAC) is an alternative therapy that removes both a source of AF-related blood clots and the risk of hemorrhagic CVA. There is now growing interest among the surgical community in LAAC performed as a prophylactic surgical procedure concomitant with other cardiac surgical procedures.
Reported in the Journal of Thoracic and Cardiovascular Surgery, Massachusetts General Hospital investigators including Thor M. Sundt, MD, chief of Cardiac Surgery, and Duke Cameron, MD, cardiac surgeon, conducted a meta-analysis of outcomes for 3897 patients from seven studies who underwent open cardiac surgical procedures, 1963 of who underwent concomitant LAAC and 1934 who did not. The study evaluated the 30-day and in-hospital risk of mortality and CVA outcomes for both groups. The studies included three randomized-controlled trial (RCT) studies, three propensity-matched studies and one case-matching study.
Because cross-study heterogeneity could be a confounding factor, heterogeneity was evaluated three ways:
- I2 score calculation; an I2 score < 50% indicates insignificant study heterogeneity
- Per-study effect; evaluated by pool recalculation after omitting studies one-by-one
- Patients were stratified by preoperative AF dominance or valve surgery dominance
The results showed odds ratios (OR) for both 30-day and in-hospital mortality and CVA of less than one, indicating the benefits of concomitant surgical LAAC. I2 scores of between-study heterogeneity were equal to 0%, further strengthening this evidence. Evaluation of per-study contribution to the pooled data indicated that one study provided the strongest evidence for reduced risk of both 30-day and in-hospital CVA and mortality. Finally, when the patients were stratified into those with preoperative AF dominance versus those undergoing a non-valve surgery (as the primary surgery), the analysis showed that concomitant LAAC was associated with reduced CVA risk for both groups, but particularly for those with preoperative AF.
Due to the lack of long-term outcome data or data on postoperative therapies in this meta-analysis (e.g. anticoagulant therapy), long-term mortality and CVA outcomes with and without various therapies could not be assessed. Finally, there was limited information on preoperative AF status (e.g. persistent or recurrent AF), which may be a confounding factor. This meta-analysis provides clear evidence of improved short-term mortality and CVA rates in patients with preoperative AF and those undergoing valve surgery.
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