Nitrate-enhanced gated technetium 99m sestamibi SPECT for evaluating regional wall motion at baseline and during low-dose dobutamine infusion in patients with chronic coronary artery disease and left ventricular dysfunction:Comparison with two-dimensional echocardiography

Background. The value of gated single photon emission computed tomography ( SPECT) in the assessment of wall motion (WM) in patients with severe perfus ion defects and in the evaluation of low-dose dobutamine (LDD)-induced chan ges is not yet established. In patients with chronic coronary artery diseas e who have left ventricular (LV) dysfunction, the results of nitrate-enhanc ed technetium 99m sestamibi (sestamibi) gated SPECT for the evaluation of r esting and LDD WM were compared with those of baseline and LDD echocardiogr aphy (LDDE). Methods and Results, Thirty-seven patients underwent echocardiography and n itrate-enhanced sestamibi gated SPECT within 1 week at rest and during LDD infusion. WM was scored from 1 (normal) to 4 (dyskinetic) by using a 16-seg ment model. Segments with sestamibi uptake less than 30% were considered un suitable for WM analysis (36 of 592 segments), Echocardiography was technic ally unreliable in 10 of 592 segments. The precise agreement between echoca rdiography and gated SPECT for baseline regional WM was 68.4% (kappa = 0.54 ), without significant differences for the involved coronary artery territo ry. The agreement for +/- 1 WM scoring was 96.5 % (kappa = 0.94). Contracti le reserve during LDD was detected by means of echocardiography in 36% and by means of sestamibi gated SPECT in 33% of baseline asynergic segments, Ag reement for detection of WM improvement in response to LDD was 74% (kappa = 0.41), The overall and +/- 1 WM score agreement for LDD WM was 67.5% (kapp a = 0.50) and 94.7% (kappa = 0.91), respectively, A significant correlation between echocardiography and gated SPECT was observed for both baseline (p = 0.78) and LDD (p = 0.74) WM score index. Conclusions. In patients with coronary artery disease who have LV dysfuncti on, nitrate-enhanced sestamibi gated SPECT allows a reliable WM evaluation, both at rest and during LDD infusion, in almost all segments and provides results in agreement with LDDE.