Comparison of Collateral Vascular Responses in the Donor and Recipient Coronary Artery During Transient Coronary Occlusion Assessed by Intracoronary Blood Flow Velocity Analysis in Patients

Objectives. This study was designed to evaluate the hemodynamic variables of the collateral circulation during acute coronary occlusion. Background. There is limited information on the physiology of the collateral circulation in coronary artery disease. Methods. Angiography of the contralateral donor artery was performed before and during balloon coronary occlusion in 57 patients with one-vessel disease. Recruitable collateral flow was assessed during coronary occlusion by blood flow analysis of the contralateral donor artery (n = 19) or the ipsilateral recipient artery (n = 15), or both (n = 23), using Doppler catheter or guide wire. Ischemi was evaluated by the ST segment shift (≥0.1 mV) on 12-lead electrocardiogram at 1 min of coronary occlusion. Results. The presence (n = 39), compared with the absence (n = 18), of recruitable collateral vessels was associated with an increase of blood flow velocity in the donor artery (20 ± 19% vs. 4.8 ± 5.9% [mean ± SD], p = 0.003) and the recipient artery (velocity integral 7.2 ± 5.5 vs. 2.8 ± 2.2 cm, p = 0.02) related to reduced relative collateral vascular resistance (9.2 ± 10 vs. 20 ± 11, p = 0.003). Collateral flow in the donor artery yielded similar predictive value for recruitability of collateral vessels as collateral flow determined in the recipient artery or the coronary wedge/aortic pressure ratio (areas under the receiver operating characteristics curves 0.76 ± 0.07, 0.78 ± 0.08, 0.77 ± 0.07, respectively, p = NS). Collateral flow in the recipient artery was better predictor for ischemi than collateral flow in the donor artery or angiographic grading of collateral vessels (areas 0.90 ± 0.05, 0.64 ± 0.10, 0.73 ± 0.07, respectively, p < 0.05). Conclusions. Coronary blood flow velocity analysis of the donor and recipient coronary arteries can characterize the dynamics of the collateral circulation during acute coronary occlusion. The protective effect of recruitable collateral vessels relates to an increase of flow in the donor and recipient coronary arteries due to reduced collateral vascular resistance. This study underscores the importance of physiologic variables for the evaluation of the function of recruitable collateral vessels.