B. Haluska*, S Wahi, P Garrahy, R Lim, T H Marwick.

Princess Alexandra Hospital, University of Queensland, Brisbane, Qld.

Assessment of vessel patency in myocardial infarction may influence interventional management but standard markers (chest pain, ST segments) have limited accuracy.  Myocardial contrast echo (MCE) may be used to assess regional perfusion by gray scale images are inaccurate due to regional variations in baseline brightness Harmonic power Doppler HPD) and digitally subtracted color coded gray scale (SCC) imaging may overcome this problem and have been used during hyperemic stress.  However, they require good image quality and their feasibility as a clinical tool in acute coronary syndromes is undefined.

Methods.  44 pts (age 65±13, 36 men) with acute myocardial infarction were studied with MCE immediately prior to coronary angiography.  MCE was performed with a harmonic transducer (1.8MHz) and standard equipment using end-systolic triggering at 1:4, 1:6, 1:8 and 1:10 after Optison infusion (MBI-Mallinkrodt).  Perfusion images were obtained in gray scale and HPD at baseline and during infusion in each view. Images underwent digital processing and 16 segts were scored by expert observers as 0 (absent), 1 (incomplete) or 2 (complete).  Ability to identify total or subtotal stenosis was evaluated by comparison with angiography (*p<0.05).

Results:  Ongoing ST elevation was present in 42 pts but 50%  had resolution of angina. Complete or subtotal occlusions were reduced in 39 pts; all had abnormal wall motion, 35 were identified by HPD and 34 by SCC (90 vs 87%, p=NS).  Patent vessels were present in 5 pts, of whom 3 had abnormal wall motion, all had abnormal HPD and 2 were abnormal by SCC.

Conclusion: Overall sensitivity of HPD and SCC are comparable, but this obscures unacceptably low sensitivity of HPD in apical 2 and long axis views.  Despite the technical difficulties of SCC this appears more accurate in acute coronary syndromes than HPD.

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