Significant correlation of recruitable coronary collateral blood flow determined by coronary wedge pressure with ST-segment elevation during coronary occlusion

Objectives: Quantitative assessment of coronary collateral blood flow can be archived by measuring coronary pressure. We studied the relationships between recruitable coronary collateral blood flow and electrocardiographic changes during percutaneous coronary intervention (PCI). Methods: We measured coronary pressure during coronary occlusion with PCI in 119 patients with left anterior descending coronary artery stenosis. During balloon inflation, the electrocardiogram was continuously recorded. The ST-segment elevation in the most elevated lead was defined as MaxST and the sum of the maximal ST elevation in leads V2-V4 was defined as ΣST. Fractional collateral flow (Qc/Q ^N) was calculated as the coronary wedge pressure divided by the mean aortic pressure. Myocardial ischemia was defined as an ST-segment shift >0.1 mV in any of the V2, V3 or V4 leads. Results: A significant relationship between Qc/Q^N and MaxST was observed (r= -0.455, P<0.0001). Similarly, Qc/Q^N was significantly correlated with ΣST (r= -0.477, P< 0.0001). The receiver operating characteristic curve showed that a cut-off value of 0.27 for Qc/Q^N, with sensitivity of 71.4% and specificity of 76.2%, was an indicator of electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Qc/Q^N values during the first, second, third and fourth inflation were not significantly different. Conclusions: Qc/Q^N could be clinically useful for determining whether there is electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Repeat transient coronary occlusion during PCI did not lead to increased collateral blood flow.