Subselective measurement of coronary blood flow velocity using a steerable Doppler catheter.

The accuracy of coronary arteriography to predict obstruction to coronary blood flow has recently been questioned. Assessment of coronary hemodynamic variables and vasodilator reserve may provide more reliable information regarding the significance of coronary stenosis. To provide a clinically safe and reliable method of measuring coronary blood flow velocity and coronary flow reserve, a 3F steerable Doppler catheter capable of subselective placement in the coronary circulation was developed and validated in an animal model. Coronary blood flow velocity measured with the catheter correlated with simultaneous measurements by a previously validated external cuff type Doppler probe (r = 0.97), coronary sinus flow collections (r = 0.78) and femoral artery flow collections (r = 0.96). The extravascular Doppler cuff measurements of rest flow velocity and vasodilator reserve were not significantly different with or without the catheter in the artery, indicating that the Doppler catheter caused no obstruction to blood flow. The Doppler catheter has recorded stable and reproducible signals without complications in 28 patients, including 62 separate arterial cannulations. Thus: 1) the 3F Doppler coronary catheter is nonobstructing, steerable and safe; 2) there is an excellent correlation of blood flow velocity with volume collections; and 3) the catheter provides a reliable method of determining coronary blood flow velocity and coronary vasodilator reserve.