Background: Collateral circulation can maintain myocardial function and viability in chronic total coronary occlusion (TCO). The present study evaluates the relation of myocardial function and duration of occlusion to collateral function.
Methods and results: A total of 50 patients underwent a successful recanalization of a TCO (>4 weeks' duration). Collateral function was assessed by intracoronary Doppler and pressure recordings before the first balloon inflation and after PTCA had been completed. Collateral function was assessed by Doppler- (CFI(D)) and pressure-derived collateral flow indices (CFI(P)), as well as indices of collateral (R(Coll)) and peripheral resistance (R(P)). Patients 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 mm Hg. cm(-1). s(-1); P=0.031) than those with akinesia. Patients with akinesia and a TCO duration of </=3 months had the highest R(Coll) and R(P), whereas those with akinesia and a longer TCO duration had similar collateral function as patients with normokinesia. After PTCA, CFI(D) and CFI(P) 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(Coll) of 139+/-128% (P<0.001) and R(P) by 65+/-99% (P=0.003). This attenuation of collateral function was less pronounced with epicardial collaterals than 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 latter group, collateral function improvement was time dependent. After recanalization, the recruitable collateral function was attenuated because of an increase of R(Coll) and R(P).