Left ventricular longitudinal strain impairment at rest correlates with reduction of SPECT-derived coronary flow reserve in patients with suspected coronary artery disease

Abstract

Background Speckle tracking echocardiography (STE) may be useful for the detection of subclinical systolic function abnormalities. Dynamic acquisition of myocardial blood flow using 99mTc-MIBI SPECT-CZT gamma camera allows the calculation of coronary flow reserve (CFR). Purpose The aim of our study is to assess the relationship between left ventricular longitudinal strain (LS) and CFR in patients with suspected coronary artery disease (CAD). Methods 55 patients (pts) (43.6% females, mean age 64.6±8.4 years) with suspected CAD underwent transthoracic echocardiography with assessment global and local LS by STE. We calculated mean global left ventricular LS (GLS), as well as LS of individual coronary artery territories (LAD LS, LCx LS and RCA LS). All pts underwent myocardial perfusion study with novel solid-state CZT nuclear camera (dipyridamole stress protocol). We measured CFR of the left ventricle and individual coronary territories. Results Mean absolute GLS in pts with total CFR <2 was significantly lower than in pts with CFR >2 (median value −13.9 vs −18.3; p<0.001). Similar differences were observed in all three coronary territories (p≤0.01). Modest but significant correlations were detected between total CFR and GLS values (r=−0.56; p<0.001), LAD CFR and LAD LS (r=−0.54; p<0.001), RCA CFR and RCA LS (r=−0.36; p=0.007), LCx CFR and LCx LS (r=−0.53; p<0.001). GLS at rest had good diagnostic value for detecting total CFR <2 (AUC=0.767; p<0.001). The criterion with the highest diagnostic accuracy was GLS > (−15.8) – its sensitivity was 68%, specificity 77.7%, and overall accuracy 73%. Conclusions Indices of left ventricular longitudinal function obtained by speckle tracking echocardiography correlate with SPECT-derived CFR in patients with suspected CAD. FUNDunding Acknowledgement Type of funding sources: None.