Comparison Of Low-dose Adenosine Echocardiography And Dual-isotope Emission Situltanoues Myocardial Perfusion Acquisition For Myocardial Viability Assessment

Background The detection of reversible myocardial dysfunction has clinical and prognostic significance, as recent studies have suggested that dysfunctional but viable segments may recover after revascularization, which could do no good for those without viable myocardium. Technologies commonly used in clinical practice includes 18-flurodeoxy-glucose positron emission tomography(PET), dual-isotope emission simultaneous myocardial perfusion acquisition(DISA), low doses dobutamine stress echocardiography(LDDSE), magnetic resonance imaging (MRI), et al.Resently,low doses adenosine stress echocardiography (LDDSE) was reported successfully introduced as a cost-effective method with comparable diagnostic potential in detecting myocardial viability.Objective To compare the value of low-dose adenosine stress echocardiography (LDASE) and dual-isotope emission simultaneous myocardial perfusion acquisition ( technetium-99-m-tetrofosmin/ flurine 18-flurodeoxy-glucose ) single-photon emission computed tomography ( DISA-SPECT ) for myocardial viability assessment in patient with acute myocardial infarction .Methods LDASE and DISA-SPECT were pereformed in 36 patients within 2 weeks after onset of first acute MI. Furthermore, at 2-3 months after acute myocardial infarction, a follow-up echocardiography was taken. A 17-segment semi-quantitative scoring model was adopted for both techniques. Wall motion improvement at follow-up compared with baseline before adenosine infusion derived from two dimensional images was used as gold criteria for myocardial viability.Results This study has found a high rate of adverse events. However, most of them were mild and transcient, which could be relieved by ceasing the infusion within 1-5mins. Compared with baseline level, with the increment of adenosine dosage, heart rate increased mildly (P=0. 037), blood pressure decreased slightly(without statistical significance); left ventricularcontractile performance was improved, ie. left ventricularend-diastolicvolume(LVESV)decreased and left ventricular ejection fraction(LVEF) increased (P value were 0.002 and 0. 0001 respectively). The sensitivity,specificity, diagnostic accuracy, positive and nagetive predictive valuefor identification of viable myocardium were 90. 3%, 80. 8%, 85.9%, 84.8%和87.5%, respectively by LDASE and81.2%, 78.3%, 81.1%, 83.1%, 80.2%,respectively by DISA-SPECT. No difference was found between LDASE andDISA-SPECT for identifying viable myocardium in hypokinetic or akineticsegment.Conclusion Adenosine could slightly increase heart rates and reduce bloodpressure, but posed no risk on hemodynamic stability. It also significantlyincreases cardiac contractile force .Sensitivity and specificity were bothhigh by LDSAE and DISA for detecting viable myocardium in AMI patients withno difference. LDASE was sensitive and specific at 100ug/kg/min adenosineinfusion with minimal adverse effect. This dosage could be recommended forfurther study.