Mechanism of increasing systolic coronary flow velocity in patients with aortic regurgitation.

Background And Aim Of The Study: The mechanism of increasing systolic coronary flow velocity of the epicardial coronary artery in patients with aortic regurgitation (AR) has not been well investigated. Thus, an evaluation was made of the flow velocity pattern of the epicardial coronary artery in these patients.

Methods: In 12 patients with AR, epicardial coronary flow velocity was monitored using Doppler guidewire, and diameter changes of the epicardial coronary artery using intravascular ultrasound (IVUS).

Results: The systolic coronary vascular resistance in AR patients was significantly less than that in controls (1.8 +/- 0.9 versus 3.3 +/- 0.7 mmHg/ml/min; p <0.01). Likewise, area and diameter changes of the epicardial coronary artery during the cardiac cycle in AR patients were significantly less than those in controls (102 +/- 1% versus 106 +/- 4%; p <0.01; and 102 +/- 1% versus 106 +/- 4%; p = 0.03).

Conclusion: In patients with AR, the increase in systolic coronary flow velocity of the epicardial coronary artery during the systolic phase was considered to result from a major coronary perfusion of blood into the intramyocardial vessels (which showed a decreased resistance), rather than it being stored in the epicardial coronary artery.