Real-Time Myocardial Contrast Stress Echocardiography Using Bolus Application

Abstract 

In myocardial contrast echocardiography (MCE), power modulation technique may quantify myocardial perfusion in real-time. However, constant infusion of the contrast agent (CA) complicates handling. This pilot study sought for the clinical feasibility of quantitative MCE by a CA bolus application during Adenosine stress echocardiography to diagnose coronary artery disease (CAD). Twenty-four consecutive patients (pts) with contemporary coronary angiography underwent rest and maximum Adenosine stress. Signal intensity could be calculated in 316/348 left ventricular (LV) segments (91%) (18-segment model). At rest, gamma-variate (alpha) as well as saturation function (beta) was not significantly different in healthy men (n = 268) as well as CAD pts (n = 48) (alpha: 0.34 s^-1 versus 0.40 s⁻¹, n.s.; beta: 0.31 s⁻¹ versus 0.35 s⁻¹, n.s.). During Adenosine infusion both values increased in healthy men (alpha: 0.34 ± 0.37 s⁻¹ versus 0.44 ± 0.45 s⁻¹, p < 0.05; beta: 0.31 ± 0.33 s⁻¹ versus 0.40 ± 0.40 s⁻¹, p < 0.01), but not in CAD (alpha: 0.40 ± 0.35 s⁻¹ versus 0.29 ± 0.29 s⁻¹, n.s.; beta: 0.35 ± 0.32 s⁻¹ versus 0.27 ± 0.30 s⁻¹, n.s.). Sensitivity of alpha/beta reserve ≤1 was 65%/67% (specificity 66%/67%) and improved to 88% in both if also wall motion analysis was considered (specificity 59%/65%). A very high negative predictive value of 96%/97% favours the method for excluding CAD. Bolus administration of CA is feasible in quantitative real-time MCE. However, additional consideration of wall motion analysis is required for reasonable sensitivity. Very high negative predictive values favour the potential of the method in excluding the diagnosis. Further need of research work may be encouraged by those findings. (E-mail: nixdorff@ecp-checkup.de)

Key Words: Myocardial contrast echocardiography, Power Doppler modulation, Myocardial perfusion, Wall motion analysis, Coronary artery disease