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Sequential (201)Tl imaging and dobutamine echocardiography to enhance accuracy of predicting improved left
Jeroen J Bax1, Jamshid Maddahi, Don Poldermans
1Department of Cardiology, University Hospital Leiden, Leiden, The Netherlands. jbax@knoware.nl
Unlabelled:
201Tl imaging and dobutamine echocardiography (DE) can both identify viable myocardium. Prediction of functional outcome after revascularization remains suboptimal with either technique because of the relatively low specificity of (201)Tl and low sensitivity of DE. This study was undertaken to develop an optimal testing strategy for prediction of post-revascularization functional outcome.
Methods:
Seventy-three patients (mean [+/-SD] left ventricular ejection fraction [LVEF], 32% +/- 8%) underwent DE and resting (201)Tl SPECT (4-h delayed imaging) before surgical revascularization. Dysfunctional segments with (201)Tl activity > or = 50% or with contractile reserve were considered viable. LVEF was assessed before and 3-6 mo after revascularization.
Results:
Analysis of receiver operator characteristic curves showed that the optimum criteria to predict improvement (> or = 5%) in LVEF after revascularization were > or = 6 viable dysfunctional segments (using a 16-segment model) on (201)Tl and > or = 4 segments on DE. Sensitivity and specificity were 84% and 63% for (201)Tl (P < 0.05 vs. DE) and 63% and 85% for DE (P < 0.05 vs. (201)Tl). Changing the (201)Tl criteria to improve specificity to 78% (> or = 8 segments) yielded a low sensitivity of 44%, and changing the DE criteria to improve sensitivity to 84% (> or = 2 segments) lowered specificity to 56%. Two sequential testing strategies were explored to achieve optimal sensitivity and specificity. In strategy 1, 33 (45%) of 73 patients with an intermediate likelihood of viability by (201)Tl (5-8 viable segments) underwent DE. In strategy 2, 31 (42%) of 73 patients with an intermediate likelihood of viability by DE (2-4 viable segments) underwent (201)Tl. For strategy 1, sensitivity did not change significantly (69%), whereas specificity was improved significantly (93%, P < 0.01 vs. (201)Tl). For strategy 2, sensitivity improved significantly (78%, P < 0.05 vs. DE) and specificity remained unchanged (80%).
Conclusion:
Sequential testing by (201)Tl SPECT and DE in a subgroup of patients with an intermediate likelihood of viability by either test significantly enhanced prediction of post-revascularization improvement of LVEF.