1028-67 Coronary Flow Reserve and Stress SPECT 201TI in Intermediate Saphenous Vein Graft Lesions

Coronary flow reserve (CFR) has become a useful means for determining the physiologic significance of native coronary lesions. While CFR normalizes following coronary bypass surgery, the utility of CFR in the evaluation of saphenous vein graft (SVG) lesions has not been defined. Therefore, we examined the correlation between CFR and stress SPECT 201TI results in 13 patients with SVG lesions of intermediate severity (40– 80% stenosis). In each patient, the SVG supplied normal myocardium, and the bypassed vessel was at least half the diameter of the SVG. Coronary flow velocity was recorded at baseline and following adenosine-induced hyperemia using an 0.014′ intracoronary Doppler guidewire. Patients subsequently underwent exercise SPECT 201TI imaging and were classified by stress 2.201TI results as being normal or having a reversible defect. Twelve SVGs without stenoses supplying normal myocardium served as controls. Control SVGs had a CFR of 2.6±0.4, (range 2.0–3.6),Normographic 201TI (n=7)Reversible 201TI (n=6)p valueCFR2.8±061.5±0.40.0001Stenosis (%)61±964±13NSMLD(mm)1.5±0.31.3±0.5NSMLD=minimal luminal diameterQuantitative angiographic sperity did not distinguish patients with evidence of ischemia by stress SPECT 201TI imaging. CFR, however, was significantly reduced in patients with reversible 2 1TI defects. Using a normal CFR of ≥2.0, the sensitivity, specificity and predictive accuracy of CFR compared to stress 201TI results were 83%, 100% and 92%, respectively. Thus, Doppler guidewire measures of CFR correlate with stress SPECT 201TI results and may be useful in determining the physiologic significance of intermediate SVG lesions