The relationship between IS/AAR and transmural coronary collateral blood flow measured at 30 min into the ischemic period. In the four groups analyzed, there was a significant (P < 0.04 to 0.0003) inverse relationship between these two parameters, as shown by linear regression analysis. In the RPCT group there was a marked parallel shift downward ( Panel B) compared with the control group (Panel A), which clearly indicates that at any given collateral blood flow one would predict a smaller IS/AAR in the RPCT group. Similar results were obtained with bradykinin as with the RPCT group [Data not shown]. Interestingly, pretreatment with 14,15-EEZE (Panel C) or MS-PPOH (Panel D), the 2 EET blockers, shifted these two lines nearly back to that of the control group.