Left Atrial Size: An Underappreciated Perioperative Cardiac Risk Factor

Abstract

LEFT ATRIAL (LA) VOLUME MEASUREMENT has been shown to have a role in the prognosis of long-term cardiovascular mortality in the community setting as well as in the prediction of adverse perioperative events. Different clinical methods have been described for LA size measurement, including magnetic resonance imaging (MRI), computerized tomography (CT), and echocardiography. In recent literature, the LA size has been shown to positively predict the risk of several pathologies (Table 1), including the recurrence of atrial fibrillation (AF), cerebrovascular accidents (CVA), myocardial infarction (MI), and overall mortality. As a result, assessment of LA size recently has received significant clinical attention as a prognostic marker as well as a tool for following response to therapy. In this regard, the value of LA size as a prognostic marker also can be extrapolated to the perioperative assessment of diastolic function. Since the Doppler-derived variables for assessment of diastolic function are extremely load-dependent, LA size provides an alternative marker of the chronicity and significance of elevated left ventricular end-diastolic pressure (LVEDP). Commonly termed as the “HbA1c” for assessment of diastolic dysfunction, the role of LA size in the recognition of long-standing diastolic dysfunction is well recognized. The presence of perioperative diastolic dysfunction has been shown to be an independent predictor of outcome in cardiac and noncardiac surgery. Therefore, knowledge of the LA size possibly can be used for perioperative risk stratification and has the potential to impact intraoperative decision-making. In this article, the authors review the physiologic importance of LA size and its impact on the assessment of diastolic dysfunction, the evidence for its use as a perioperative marker