Left atrial contractile function following a successful modified Maze procedure at surgery and the risk for subsequent thromboembolic stroke.

OBJECTIVES: The aim of this study was to evaluate whether certain post-Maze left atrial (LA) contractile profiles may pose a risk for ischemic stroke.
BACKGROUND: The mechanical contraction of the left atrium may be modified after the Maze procedure. Whether this imposes a risk for stroke, even in the presence of sinus rhythm and after removal of the LA appendage, is not known.
METHODS: Clinical, surgery-related, and echocardiographic data from 150 patients who underwent radiofrequency and cryoablation Maze procedures without the use of atrial incisions between 2004 and 2009 and were in sustained sinus rhythm were collected and analyzed. The occurrence of stroke was evaluated by reviewing clinical records. All stroke events were adjudicated by a neurologist.
RESULTS: At a mean follow-up time of 24.5 months, 15 patients (10%) had experienced ischemic strokes. Forty-seven patients (31%) had no evidence of LA mechanical contraction at 3 months after surgery (baseline assessment) and on follow-up echocardiography. Multivariate analysis showed that a lack of LA mechanical contraction at baseline was associated with a 5-fold increase in the risk for stroke (p = 0.02) during follow-up. Larger atria imposed a significant risk as well; LA volume index ≥33 ml/m(2) was associated with a 3-fold risk increase (p = 0.03). These effects were maintained regardless of the lack of mechanical valve implantation and anticoagulation treatment.
CONCLUSIONS: Absence of LA contraction and LA volume index ≥33 ml/m(2) result in a significant increase in the risk for thromboembolic stroke after the Maze procedure for patients in sinus rhythm.