Abstract 3341: Human Coronary Collaterals Inversely Correlate with Indices of Ischemic Left Ventricular Diastolic Dysfunction during Coronary Balloon Occlusion.
Background: Coronary collaterals are thought to reduce myocardial ischemia during coronary artery occlusion. Coronary collaterals, defined angiographically, reduce end diastolic LV dilatation during coronary occlusion. However, counter to a role in reducing ischemia, they appear to be associated with an increase in LV end diastolic pressure. These changes may be explained if coronary collaterals act as an external LV scaffold. We aimed to re-evaluate this relationship by simultaneously measuring coronary collaterals and LV contractility quantitatively.
Methods: Ten patients with normal LV function and single vessel coronary disease awaiting PCI were recruited. Collateral flow index, derived by pressure-wire measurement (CFIp = [Pdistal (occluded) − Pvenous] / [Paorta − Pvenous]) and change in LV end-diastolic pressure (LVEDP), volume (LVEDV) and Tau, measured by an LV cavity conductance catheter, were recorded simultaneously after 1 minute coronary balloon occlusion. A mean of 5 cardiac cycles was analyzed. Measurements were repeated after a recovery period of 30 minutes.
Results: Percentage change in LVEDP and Tau inversely correlated with CFIp (ΔLVEDP vs. CFIp: y = −216.6x +63.4, r = 0.57, p=0.01; ΔTau vs. CFIp: y = −64.1x + 27.8, r = 0.47, p<0.05) (Figure⇓). There was also an inverse relationship between ΔLVEDV vs. CFIp (y = −8.4x + 1.5, r = 0.35, p = 0.15).
Conclusion: Coronary collaterals inversely correlate with LV end diastolic stiffness and dilatation after 1 minute of coronary artery occlusion. This reflects a role in reducing ischemic LV diastolic dysfunction, by providing an alternative blood supply to the LV myocardium, rather than acting as an LV scaffold.