A method for assessing the physiologic significance of coronary obstructions in man at cardiac surgery.

The functional significance of coronary narrowings of intermediate severity is often difficult to assess from preoperative coronary arteriograms. To complement the anatomic data obtained by arteriography, a method for measuring phasic coronary velocity and reactive hyperemia in man at cardiac surgery has been developed. The method uses a single-crystal Doppler probe coupled to surface coronary vessels with a small suction pad. The validity of the measurements has been documented in a series of in vitro and animal experiments. Because physiologically significant coronary narrowings invariably attenuate reactive hyperemic responses, this approach can be used to determine the functional importance of coronary obstruction before placement of coronary bypass grafts. Initial experience in 50 patients indicates that the measurements can be obtained safely and that the functional significance of coronary obstructions can be readily assessed.