Speckle tracking echocardiography allows for the detection of subclinical myocardial dysfunction resulting from perfusion abnormalities confirmed by SPECT-based CFR measurement

Abstract

Abstract Background Speckle tracking echocardiography (STE) is helpful for the detection of subclinical systolic function abnormalities. Coronary flow reserve (CFR) measured by dynamic 99mTc-MIBI SPECT-CZT gamma camera allows the diagnosis of myocardial perfusion defects in patients with suspected coronary artery disease (CAD). Purpose The aim of our study is to assess the diagnostic value of STE and SPECT-based CFR in patients with suspected coronary artery disease (CAD). Methods 85 patients (pts) (37.6% females, mean age 65.4 ± 8.5 years) with suspected CAD underwent 2D and 3D STE, as well as myocardial perfusion study with novel solid-state CZT nuclear camera (dipyridamole stress protocol). We calculated global longitudinal left ventricular strain (GLS), as well as LS of individual coronary artery territories (LAD LS, Cx LS and RCA LS). Total CFR and CFR in three coronary territories were also measured. The presence of CAD (coronary artery stenosis > 70%) was assessed by coronary angiography. Results Significant CAD was confirmed in 50 patients. Mean total CFR (1.71 ± 0.61 vs 2.1 ± 0.52, p = 0.002), as well as CFR in LAD territories (1.54 ± 0.68 vs 1.91 ± 0.56, p = 0.02), RCA territories (1.58 ± 0.82 vs 1.95 ± 0.68, p = 0.048) and Cx territories (1.58 ± 0.78 vs 2.08 ±0.76, p = 0.01) were lower in pts with CAD. In the ROC curve analysis of total CFR for the diagnosis of CAD the AUC was found to be 0.7 (p = 0.001). Mean absolute 2D GLS in pts with total CFR < 2.0 was significantly lower than in pts with CFR >= 2.0 (-14.5 ± 4.3 vs -16.9 ± 3.4, p = 0.005). Similar differences were observed in all three coronary territories (p ≤ 0.05). The same results were not observed in case of 3D GLS . Modest but significant correlations were detected between total CFR and 2D GLS values (r = -0.38; p < 0.001), LAD CFR and 2D LAD LS (r = -0.33; p = 0.002), LCx CFR and 2 D LCx LS (r = -0.39; p < 0.001), total CFR and EF (r = 0.36; p < 0.001). GLS at rest had good diagnostic value for detecting total CFR < 2 (AUC= 0.7; p = 0.004). The criterion with the highest diagnostic accuracy was GLS > (- 18.5) – its sensitivity was 84%, specificity 42%, positive predictive value 0.7, negative predictive value 0.7 and overall accuracy 66%. Conclusions CFR assessed by SPECT provides acceptable diagnostic accuracy for the detection of significant CAD. STE allows for identification of patients with subclinical dysfunction resulting from perfusion abnormalities confirmed by SPECT-based CFR measurement.