[Measuring blood flow velocity in the coronary sinus with Doppler catheters]

Measurements of the coronary sinus blood flow velocity with Doppler catheters (Medtronic Floscan; Millar DC201) were performed to assess coronary flow reserve and significance of coronary artery stenosis. In seven patients with normal coronary angiogram coronary sinus blood flow velocity (Doppler catheters) and coronary sinus blood flow volume (thermodilution) were simultaneously recorded. Coronary flow reserve was calculated as the quotient of the peak flow velocity (peak flow volume) and resting flow velocity (resting flow volume) after infusion of 0.5 mg/kg dipyridamole intravenously. The correlation coefficient was r = 0.88. Coronary sinus blood flow velocity was measured in 31 patients at resting conditions and after injection of contrast media during coronary angiography. At resting conditions blood flow velocity was 3.6 +/- 1.5 cm/s (n = 31), 3.5 +/- 1.8 cm/s (n = 9; controls), and 3.6 +/- 1.1 cm/s (n = 9; significant stenosis of the left anterior descending; not significant). After injection of contrast media flow velocity amounted to 2.2-fold resting flow in controls and to 1.5-fold resting flow in patients with stenoses of the left anterior descending artery (p less than 0.01). Measurement of coronary sinus blood flow velocity with Doppler catheters is a valuable adjunct for determination of coronary flow reserve and for assessment of stenosis severity of the left anterior descending artery. Continuous on-line monitoring of phasic flow velocity provides important information of the myocardial perfusion, e.g., during angioplasty.