[Can adenosine triphosphate induce maximal hyperemic response in patients with impaired coronary microcirculation?: comparison of hyperemic response to adenosine triphosphate administered by intravenous and by intracoronary injection using Doppler guide wire].

OBJECTIVES

This study compared the hyperemic responses to adenosine triphosphate (ATP) administered by intravenous and by intracoronary injection in patients with impaired coronary microcirculation.

METHODS

The hyperemic responses to intravenous and intracoronary administration of ATP in 107 patients (mean age 63 +/- 10 years, 77 males, 30 females) with impaired coronary circulation [including myocardial infarction (n = 68), cardiomyopath (n = 20) and diabetes mellitus (n = 11)] were compared by measurement of coronary flow reserve (CFR) using the Doppler guide wire. Patients with chest pain syndrome were used as the normal controls. The coronary blood flow velocity was measured at rest and during peak hyperemic responses to intravenous infusion (150 micrograms/kg/min) and intracoronary infusion of ATP (50 micrograms in the left coronary artery, 25 micrograms in the right coronary artery). The CFR was calculated as the ratio of averaged peak velocity during hyperemia to baseline averaged peak velocity.

RESULTS

The CFR after intravenous administration of ATP (CFRi.v.) was well correlated with CFR by intracoronary administration of ATP(CFRic) (r = 0.77, p < 0.001). However, the CFRi.v. was also inversely correlated with the ratio of CFRic to CFRiv (CFRic/i.v.) (r = -0.36, p < 0.001). There were no relationships between the changes of hemodynamic parameters(blood pressure and heart rate) induced by ATP and CFRic/i.v. A lower CFRi.v. of less than 2.0 provided significantly greater CFRic/i.v. than that of CFRiv greater than 2.0.

CONCLUSIONS

The maximal hyperemic response of coronary artery was not always induced by conventional intravenous administration of ATP, especially in patients with lower CFR than 2.0. High dose of intravenous ATP and/or intracoronary ATP should be administered in patients with lower CFR to attain maximum hyperemia in the impaired coronary circulation.