Long-term reproducibility of coronary flow velocity measurements in patients with coronary artery disease.
N ew developments in transducer technology and signal analysis have increased the applicability of intracoronary Doppler ultrasonography for the measurement of coronary blood flow velocity. Intracoronary Doppler guide wires are used to estimate the severity of intermediate lesions,’ to define the functional results of coronary interventions,2 and to study coronary flow changes after pharmacological treatment.3 A prerequisite for these clinical and research applications is the validation of the long-term reproducibility of flow velocity measurements. This study assesses the long-term changes of baseline and hyperemic flow velocity and coronary Bow reserve in 31 patients with coronary artery disease. . . . Thirty-one patients with stable angina and single-vessel disease (age 58 -+ 9 years, 23 men and 8 women) undergoing percutaneous revascularization participated in this study. None of the patients had anemia, hyperthyroidism, or diabetes mellitus. Systemic hypertension was present in 6 of 31 patients (19%). All vasoactive medication, with the exception of short-acting nitrates, was interrupted 48 hours before the study. A 0.018-inch or 0.014-inch diameter Doppler guide wire (FloWire, Cardiometrics, Mountain View, California) was advanced into the mid-segment of an artery that was without diameter reductions greater than 30%, was not originating collaterals for the occluded vessel, and was without wall contraction abnormalities in its territory of distribution. The left anterior descending coronary artery was studied in 6 patients, the left circumflex in 13 patients, and the right coronary artery in 12 patients. Sevento 9Fr guiding catheters were used for the left coronary artery, and 7Fr diagnostic catheters for the right coronary artery. Flow velocity was recorded (FloMap, Cardiometrics, Mountain View, California) at the peak effect of an intracoronary bolus of 12 (left coronary artery) or 8 mg (right coronary artery) of papaverine, after withdrawal of the guiding catheter if signs of obstruction to i3ow were present. Five minutes after the injection of papaverine, allowing the restoration of basal conditions, a new flow velocity and a cineangiogram were recorded (Figure 1). During measurement of hyperemic and baseline velocity, heart rate and aortic blood pressure were simultaneously recorded and measured. After a follow-up period of 4 to 7 months (mean 5.8 months), hyperemic and baseline coronary flow velocity were recorded in the same position and by using the same material and protocol. The Doppler system that was used automatically calculates on-line a temporal average (mean of two beats) of the peak velocity, detected after spectral analysis of the Doppler signaL Manual retracing and calculation with an off-line system was required for 16% of the measurements because of partial or complete failure of the detection algorithm. Coronary flow reserve was calculated as the ratio between mean (time-averaged peak) hyperemic velocity and baseline velocity. The vessel diameter at the site of the Doppler sample volume was measured off-line using a tine-film system (CAAS 2, Pie Medical Data, Maastricht, The Netherlands) based on the computer-assisted application of an automatic edgedetection algorithm. The angiographic catheter was used