SAFETY AND OPTIMAL DOSE OF INTRACORONARY ADENOSINE 5'-TRIPHOSPHATE FOR THE MEASUREMENT OF CORONARY FLOW RESERVE

Background Adenosine 5'-triphosphate (ATP) has been demonstrated to ha ve similar vasodilator potency and fewer hemodynamic or electrocardiog raphic derangements compared with papaverine in the measurement of cor onary flow reserve. However, there is little data about its optimal do se and the effect on myocardial lactate metabolism. Methods Under cont inuous monitoring of the left anterior descending coronary flow veloci ty with a Doppler guide wire, we investigated the changes of hemodynam ics, electrocardiogram, and myocardial lactate metabolism before and a fter the administration of 50 mu g ATP and 10 mg papaverine into the l eft coronary artery in 18 patients with normal coronary arteries. To d etermine the optimal dose of ATP for the coronary flow reserve in the left coronary artery, we measured coronary flow velocity with five inc remental doses of intracoronary ATP (0.5, 5, 15, 30, and 50 mu g) and 10 mg of papaverine in another seven patients.Results In contrast to p apaverine, ATP did not produce any significant changes in hemodynamics or the electrocardiogram. The increase in the coronary flow velocity of the two agents was similar. Although all patients showed lactate pr oduction after the administration of papaverine, only three patients s howed lactate production after ATP (p < 0.001). The coronary flow rese rve derived from greater than or equal to 15 mu g of ATP was similar t o that derived From papaverine. There was a significant correlation be tween the coronary flow reserve obtained with greater than or equal to 5 mu g of ATP and that obtained with papaverine. Conclusions These re sults suggest that maximal coronary vasodilation in the left coronary artery can be safely obtained with doses greater than or equal to 15 m u g of intracoronary ATP in patients with normal coronary arteries.