[Coronary flow velocity reserve and collateral resistance after recanalization of chronic total coronary occlusions and periprocedural CK and cTNI elevation]

Abstract

After recanalization and stenting of chronic total coronary occlusions (TCO), a reduced coronary flow velocity reserve (CFVR) and rise in collateral resistance (R(Coll)) is frequently observed. Coronary microembolization may account for these observations. In 86 patients (age 64+/-10 years; 77 men, 9 women) with TCO (duration >4 weeks), PTCA was performed with successful stent implantation in all lesions. Before PTCA, viable myocardium was detected by stress echocardiography or nuclear imaging techniques. By simultaneously measuring coronary Doppler flow velocity and pressure before and after PTCA, CFVR and R(Coll) were calculated. Over a period of 24 hours after intervention, creatine kinase (CK; upper limit of normal [ULN] for women 1.17 micromol/L/s, for men 1.33 micromol/L/s) and cardiac troponin I (cTNI; threshold 0.1 ng/mL) were studied. CFVR was <2 in 48% of all patients. A rise in R(Coll) was observed in 83% of all patients. The incidence of CK and/or cTNI elevation was only observed in 10% of all patients. These patients with CK and/or cTNI elevation did not show a significant difference of CFVR and rise in R(Coll) as compared with patients without CK and cTNI elevation. CFVR or rise in R(Coll) did not correlate with CK elevation. Coronary microembolization is not a likely cause of reduced CFVR and increased R(Coll) after PTCA of TCO. Other factors such as microvascular dysfunction and autoregulatory changes in collateral function may account for these observations.