Diagnostic Concordance and Clinical Outcomes in Patients Undergoing Fractional Flow Reserve and Stress Echocardiography for the Assessment of Coronary Stenosis of Intermediate Severity

Background The ischemic consequences of coronary artery stenosis can be assessed by invasive fractional flow reserve (FFR) or by noninvasive imaging. We sought to determine (1) the concordance between wall thickening assessment during clinically indicated stress echocardiography (SE) and FFR measurements and (2) the factors associated with hard events in these patients. Methods Two hundred twenty-three consecutive patients who underwent SE and invasive FFR measurements in close succession were analyzed retrospectively for diagnostic concordance and clinical outcomes. Results At the vessel level, the sensitivity, specificity, positive predictive value, and negative predictive value of SE for identifying significant disease as assessed by FFR was 68%, 75%, 43%, and 89%, respectively. The greatest discordance was seen in patients with wall thickening abnormalities (WTAs) and negative FFR. During a follow-up of 3.6 ± 2.2 years, there were 23 cardiovascular (CV) events (death and nonfatal myocardial infarction). The number of wall segments with inducible WTAs emerged as the strongest factor associated with CV events (hazard ratio, 1.18 [1.05-1.34]; P  = .008). FFR was not associated with outcome. There was a significant increase in event rate in patients with WTA/negative FFR versus no WTA/negative FFR ( P  = .01), but no significant difference versus WTA/positive FFR ( P  = .85). Conclusions In a patient population with significant CV risk factors, a normal SE had a high negative predictive value for excluding abnormal FFR. WTAs were associated with outcomes regardless of FFR value, suggesting that this is a superior marker of ischemia to FFR.