Coronary collaterals preserve left ventricular (LV) function during
coronary occlusion by reducing
myocardial ischemia and may directly influence LV compliance. We aimed to re-evaluate the relationship between coronary collaterals, measured quantitatively with a pressure wire, and simultaneously recorded LV contractility from conductance
catheter data during
percutaneous coronary intervention (PCI) in humans. Twenty-five patients with normal LV function awaiting PCI were recruited. Pressure-derived collateral flow index (
CFI(p)):
CFI(p) = (P(w) - P(v))/(P(a) - P(v)) was calculated from pressure distal to coronary balloon occlusion (P(w)), central venous pressure (P(v)), and aortic pressure (P(a)).
CFI(p) was compared with the changes in simultaneously recorded LV end-diastolic pressure (ΔLVEDP), end-diastolic volume, maximum rate of rise in pressure (ΔLVdP/dt(max); systolic function), and time constant of isovolumic relaxation (ΔLV τ; diastolic function), measured by a LV cavity conductance
catheter. Measurements were recorded at baseline and following a 1-min
coronary occlusion and were duplicated after a 30-min recovery period. There was significant
LV diastolic dysfunction following
coronary occlusion (ΔLVEDP: +24.5%, P < 0.0001; and ΔLV τ: +20.0%, P < 0.0001), which inversely correlated with
CFI(p) (ΔLVEDP vs.
CFI(p): r = -0.54, P < 0.0001; ΔLV τ vs.
CFI(p): r = -0.46, P = 0.0009). Subjects with fewer collaterals had lower LVEDP at baseline (r = 0.33, P = 0.02).
CFI(p) was inversely related to the
coronary stenosis pressure gradient at rest (r = -0.31, P = 0.03). Collaterals exert a direct hemodynamic effect on the ventricle and attenuate ischemic
LV diastolic dysfunction during
coronary occlusion. Vessels with lesions of greater hemodynamic significance have better collateral supply.