Left ventricular dyssynchrony in coronary artery disease: Assessment of gated SPECT and 256-MSCT coronary angiogram

Objectives We validate a new index that quantifies left ventricular (LV) dyssynchrony using gated myocardial perfusion SPECT (GMPS) and investigate the utility of diagnosing multi-vessel coronary artery disease (CAD), referenced the results of 256-multislice CT coronary angiogram (CTCA) as standards.

Methods In 42 patients (26 male, 16 female; age range, 25-83 y; mean age, 66.3±11.9 y) with suspected or known CAD, retrospective ECG gated CTCA and stress/redistribution 201-thallium GMPS were performed. On the basis of the AHA 17 segment model, LV wall thickness (mm) on CTCA and %uptake on redistribution images of GMPS for each segment were measured at end-systole and end-diastole. The correlation with wall thickness and %uptake was analyzed by Pearson’s product-moment coefficient. The coefficient of variance (CV) of %uptake for each patient was used as an estimate of LV dyssynchrony. The difference in CV was analyzed by Mann-Whitney U-test.

Results CTCA detected 24 patients with insignificant/single-vessel CAD and 18 with multi-vessel CAD. Significant correlation was obtained between wall thickness and %uptake at end-systole and end-diastole (r=0.22, p<0.0001; r=0.21, p<0.0001). The CV was significantly greater for multi-vessel [15.6±5.9 (mean±SD), 15.6±4.4] than for insignificant/single-vessel CAD (9.9±3.0, 9.5±2.6) at end-systole and end-diastole (p=0.0006, p<0.0001). Use of CV of 11.5 at end-diastole differentiated patients with multi-vessel CAD from those with insignificant/single-vessel CAD with a sensitivity of 83% and with a specificity of 83%.

Conclusions The CV of myocardial uptake on GMPS was an index of reflecting LV dyssynchrony because regional uptake corresponded to the alterative wall thickness during cardiac cycle. The CV at end-diastole was the most boundary index between patients with multi- and single-vessel CAD