Collateral function in chronic total coronary occlusions is related to regional myocardial function and duration of occlusion

Background-Collateral circulation can maintain myocardial function and viab ility in chronic total coronary occlusion (TCO). The present study evaluate s the relation of myocardial function and duration of occlusion to collater al function. Methods and Results-A total of 50 patients underwent a successful recanaliz ation of a TCO (>4 weeks' duration). Collateral function was assessed by in tracoronary Doppler and pressure recordings before the first balloon inflat ion and after PTCA had been completed. Collateral function was assessed by Doppler- (CFID) and pressure-derived collateral flow indices (CFIP), as wel l as indices of collateral (R-Coll) and peripheral resistance (R-P). Patien ts with normokinesia had lower R-Coll (4.9 +/-2.5 versus 11.8 +/-8.2 mm Hg . cm(-1) . s(-1); P=0.033) and lower R-P (3.8 +/-1.9 versus 6.1 +/-4.1 min Hg . cm(-1) . s(-1); P=0.031) than those with akinesia. Patients with akine sia and a TCO duration of less than or equal to3 months had the highest R-C oll and R-P, whereas those with akinesia and a longer TCO duration had simi lar collateral function as patients with normokinesia, After PTCA, CFID and CFIP decreased from 0.37 +/-0.20 to 0.21 +/-0.17 (P <0.001) and from 0.44 +/-0.12 to 0.36 +/-0.11 (P <0.001), respectively, With an increase in R-Col l of 139 +/- 28% (P <0.001) and R-P by 65 +/- 99% (P=0.003). This attenuati on of collateral function was less pronounced with epicardial collaterals t han with intramyocardial collaterals. Conclusions-Collateral function was better in patients with TCO and normal regional function than in those with impaired regional function. In the lat ter group, collateral function improvement was time dependent. After recana lization, the recruitable collateral function was attenuated because of an increase of R-Coll and R-P.