Incremental doses of intracoronary adenosine for the assessment of coronary velocity reserve for clinical decision making

Achievement of maximal vasodilatation of the coronary microcirculation is a prerequisite for the measurement of coronary flow reserve (CFR). The prese nt study was designed to address the hypothesis that intracoronary adenosin e yields more complete vasodilation of the coronary microcirculation when i ncremental doses are used, resulting in higher and more accurate coronary f low reserve measurements. Four hundred and fifty-seven patients were divide d in two groups; group I (319 patients) comprised patients without angiogra phic evidence of significant coronary artery disease, while group II (138 p atients) comprised patients with intermediate coronary stenoses (between 40 % and 70% diameter stenosis). Coronary velocity reserve (CVR, a surrogate m easurement for CFR) was measured during cardiac catheterization using a Dop pler-tipped guidewire. Incremental doses of intracoronary adenosine (12 to 54 mug for the left coronary artery and 6 to 42 mug for the right coronary artery) were administered. There was a significant difference between the i nitial dose of adenosine and the subsequent incremental doses. Of a total o f 479 observations, only 192 (40%) had the maximal CVR value at the first d ose. Thirty-nine percent of the patients in group I and 27% in group II wit h an initial CVR value < 2.5 increased CVR to greater than or equal to 2.5 with incremental doses of adenosine. This study suggests that incremental d oses of adenosine should be used to achieve maximal CVR for the assessment of the functional significance of coronary lesions. (C) 2001 Wiley-Liss, In c.