Coronary flow velocity analysis showed significantly lower diastolic flow in the proximal right coronary artery compared to the left main stem (35.1 vs. 56.4 cm/s, P<0.002).
Observational (n=20)
Does the distal-originating suction wave explain the differences in flow-velocity waveforms between the left main stem and right coronary artery in subjects with unobstructed coronary arteries?
The difference in flow-velocity waveforms between the left and right coronary arteries is primarily due to a smaller distal-originating suction wave in the RCA, reflecting differences in ventricular elastance and pressure.
Absolute Event Rate: 56.4% vs 35.1%
p-value: p=<0.002
Despite having almost identical origins and similar perfusion pressures, the flow-velocity waveforms in the left and right coronary arteries are strikingly different. We hypothesized that pressure differences originating from the distal (microcirculatory) bed would account for the differences in the flow-velocity waveform. We used wave intensity analysis to separate and quantify proximal- and distal-originating pressures to study the differences in velocity waveforms. In 20 subjects with unobstructed coronary arteries, sensor-tipped intra-arterial wires were used to measure simultaneous pressure and Doppler velocity in the proximal left main stem (LMS) and proximal right coronary artery (RCA). Proximal- and distal-originating waves were separated using wave intensity analysis, and differences in waves were examined in relation to structural and anatomic differences between the two arteries. Diastolic flow velocity was lower in the RCA than in the LMS (35.1 +/- 21.4 vs. 56.4 +/- 32.5 cm/s, P < 0.002), and, consequently, the diastolic-to-systolic ratio of peak flow velocity in the RCA was significantly less than in the LMS (1.00 +/- 0.32 vs. 1.79 +/- 0.48, P < 0.001). This was due to a lower distal-originating suction wave (8.2 +/- 6.6 x 10(3) vs. 16.0 +/- 12.2 x 10(3) W.m(-2).s(-1), P < 0.01). The suction wave in the LMS correlated positively with left ventricular pressure (r = 0.6, P < 0.01) and in the RCA with estimated right ventricular systolic pressure (r = 0.7, P = 0.05) but not with the respective diameter in these arteries. In contrast to the LMS, where coronary flow velocity was predominantly diastolic, in the proximal RCA coronary flow velocity was similar in systole and diastole. This difference was due to a smaller distal-originating suction wave in the RCA, which can be explained by differences in elastance and pressure generated between right and left ventricles.
Hadjiloizou et al. (Fri,) conducted a observational in Unobstructed coronary arteries (n=20). Left main stem (LMS) flow velocity measurement vs. Right coronary artery (RCA) flow velocity measurement was evaluated on Diastolic flow velocity (cm/s) (p=<0.002). Coronary flow velocity analysis showed significantly lower diastolic flow in the proximal right coronary artery compared to the left main stem (35.1 vs. 56.4 cm/s, P<0.002).