Left atrial functional assessment a prime clue in solving the puzzle of stable angina symptoms in suspected coronary artery disease patients

Abstract

Abstract Background Assessing clinically for significant coronary artery disease (CAD) in stable angina patients presents a formidable task. Routinely performed echocardiography is limited in diagnosing CAD with provision for the regional wall motion abnormality (RWMA) for left ventricle (LV) systolic dysfunction and altered mitral inflow velocities for LV diastolic dysfunction. However, the advent of two-dimensional (2D) speckle-tracking technique has established the era of strain imaging, opening new possibilities in echocardiography. It is now possible to have a detailed functional assessment of left atrium (LA). We utilised speckle tracking imaging to obtain strain parameters for LA function. Combining these strain parameters with the doppler myocardial velocities and mitral inflow velocities, may prove useful mode of imaging to diagnose significant CAD in stable angina patients. Purpose To study the parameters of left atrial functions utilising echocardiographic strain imaging and evaluate their correlation with the syntax score-II in patients with symptoms of stable angina. Methods 103 patients with symptoms of stable angina undergoing coronary angiography for suspected coronary artery disease(CAD), were considered for LA function assessment and compared with their syntax-II score. Results The LA reservoir function parameters, peak atrial longitudinal strain (PALS) and peak global systolic strain rate (LAsSR), decreased with increasing syntax-II score (p values 0.011 and 0.001 respectively) and the parameter of LA conduit function, peak global early diastolic strain rate (LAeSR) increased (p value <0.001). The LA filling pressures reflected by E/e`, also increased with more severe syntax-II score (p value <0.001). We, further, configured cut off values of < 23.56 for PALS, < 1.15 for LAsSR, > -1.09 for LAeSR, and E/e` ratio > 10.39 as predictors of significant CAD, with good sensitivity and specificity. Therefore, stable angina patients who had significant CAD on coronary angiogram represented by severe syntax score-II, had higher LA filling pressures and deranged LA function with transition from more of reservoir chamber to merely a conduit. Conclusion Our study shows a significant association between LA strain parameters (PALS, LAsSR, and LAeSR) and LA filling pressures (E/e`), with the presence of significant CAD in these patients. The stable angina patients with more severe CAD as quantified by their severe syntax score-II, have an impaired LA reservoir and LA functions more as a conduit, with elevated filling pressures. This study establishes a significant association between LA deformation strain variables and severity of CAD and hence LA strain imaging can be a useful tool to diagnose significant CAD in stable angina patients.