Abstract 1844: Coronary Microcirculation Suction Wave is Reduced in Left Ventricular Hypertrophy: A Novel Assessment Using Wave Intensity Analysis
Background: Coronary blood flow peaks in diastole when aortic pressure has fallen. Current models fail to completely explain this phenomenon. We present a new approach - using wave intensity analysis - to explain this phenomenon in normal subjects, and to evaluate the effects of left ventricular hypertrophy(LVH) on the coronary microcirculation.
Method: Simultaneous pressure and Doppler velocity were measured using intracoronary wires in the left main stem, left anterior descending, and circumflex arteries of 20 subjects (mean age 54 ± 10years, 13 female) following a normal coronary arteriogram. Coronary wave speed was calculated using a new method we have recently developed and wave intensity analysis then applied.
Results: A consistent pattern of six predominating waves was identified. 94% of wave energy, accelerating coronary blood forward, came from two waves: first a pushing-wave from left ventricular ejection and later a suction-wave from relief of microcirculatory compression. This suction-wave (18.2 ± 13.7 x103 W.m−2s−1, 30%) was larger than the pushing-wave (14.3 ± 17.6 x103 W.m−2s−1, 22.3%, p=0.001) and was associated with a substantially larger incremental increase in coronary flow velocity (0.51 versus 0.14 m/s, p<0.001). In LVH, the suction-wave was decreased (33.1 v 26.9%, p=0.01) and inversely correlated with septal wall thickness (r=−0.52, p<0.02).
Conclusion: Six waves predominantly drive human coronary blood flow. Coronary flow peaks in diastole because of the dominance of a suction-wave generated by microcirculatory decompression. This is significantly reduced in LVH.