Influence on collateral flow of recanalising chronic total coronary occlusions: a case-control study

Objective-To assess the effect of recanalisation on collateral flow in a ca se-control study in patients with and without chronic total coronary occlus ions. Design In 54 patients undergoing percutaneous transluminal coronary angiopl asty (PTCA) (mean (SD) age 61 (6) years), coronary collateral flow was meas ured by intracoronary pressure or Doppler guide wires at the end of repeate d balloon occlusions. Coronary collateral flow index (collateral flow relat ive to normal antegrade flow) during the first two balloon inflations in 27 patients with a chronic total occlusion (occlusion group) was compared wit h that of 27 patients matched for age, sex, and collateral flow index at th e first occlusion and with a coronary artery diameter stenosis less than or equal to 80% (stenosis group). Results Following revascularisation, collateral flow index decreased in 17 of the patients in the occlusion group (63%) and in eight of the patients i n the stenosis group (30%) (p = 0.03 between groups). The overall change of collateral flow index between the first and the second balloon occlusion w as -0.04 (0.01) in the occlusion group (p = 0.07 for paired comparison; fro m 0.29 (0.17) to 0.25 (0.14)), and +0.02 (0.06) in the stenosis group (p = 0.06 for paired comparison; from 0.27 (0.13) to 0.30 (0.15)). The trend to collateral enhancement in the stenosis group differed significantly from th e occlusion group (p = 0.01). Conclusions-While repeated coronary balloon occlusions induce collateral re cruitment in the majority of patients with moderate stenoses, recanalisatio n of chronic total coronary occlusions is more often associated with collat eral flow reduction. A later decrease in collateral flow by involution of c ollateral channels cannot be excluded by this study but has not been report ed so far.