913-119 Coronary Angiographic and Doppler Flow Correlates of Technetium-99m Sestamibi Myocardial Perfusion Abnormalities Following Successful Coronary Angioplasty

Abstract

Thallium-201 myocardial perfusion defects may persist in studies performed early after angiographically successful percutaneous transluminal coronary angioplasty(PTCA), The causes for and frequency of post-PTCA technetium 99m sestamibi (MIBI) perfusion abnormalities have not been elucidated in man, We examined the post-PTCA quantitative coronary angiographic and distal/proximal (d/p) intracoronary Doppler average peak flow velocity (APV) correlates of MIBI myocardial tomography in tie PTCA perfusion beds of 34 consecutive pts (M = 19, F = 15; age = 57 ± 14 yrs), The average pre-PTCA % diameter stenosis [%DS in LAD = 15, RCA = 10, LCX = 6, graft = 3] was 78 ± 15%. Same-day rest-stress MIBI tomograms were blindly scored for the presence and # of reversible myocardial defects in post-PTCA perfusion beds using a 20 segment model. Results of pts with normal (n = 24) and abnormal (n = 10) MIBI scans are compared below: Normal MIBI Abnormal MIBI p value PTCA-Scan Interval (wks) 4.9 ± 3.3 4.2 ± 4.6 NS Post-PTCA %DS (%) 24 ± 11 23 ± 13 NS Min. Luminal Diam. (mm) 2.1 ± 0.5 2.3 ± 0.6 NS d Coronary Flow Reserve 18 ± 0.6 1.6 ± 0.8 NS Post-PTCA dip APV Ratio 12 ± 0.7 06 ± 0.3 0.05 Pts with an abnormal post-PTCA dip APV ratio < 1 had significantly more reversible MIBI defects in the PTCA myocardial perfusion bed (2.5 ± 3.2 vs. 0.2 ± 0.5; p = 0.04). We conclude that MIBI myocardial perfusion defects persist in 29% of pts between 4–5 wks after successful PTCA. The relative post-stenotic flow reduction in these patients suggests a mechanism for post-PTCA reversible perfusion defects beyond abnormal coronary flow reserve and residual stenosis alone.