Effect of body mass index on the efficacy, side effect profile, and plasma concentration of fixed-dose regadenoson for myocardial perfusion imaging.

Background: There are limited data on the effect of body mass index (BMI) on the actions of fixed-dose regadenoson. The purpose of this study was to determine the effect of BMI on the efficacy, side effects, and plasma concentration of regadenoson for Myocardial Perfusion Imaging (MPI). Methods and Results: The study included 2,015 subjects from the ADVANCE MPI trials. Initial adenosine MPI was followed by randomization to regadenoson (400-μg bolus injection) or adenosine (6-minute infusion) MPI. Subjects were classified according to BMI into six categories from underweight (<20 kg/m) to extremely obese (≥40 kg/m). PK modeling was used to predict the effect of BMI on plasma regadenoson concentration (PRC). Adenosine-regadenoson agreement rates for the presence and extent of reversibility were similar across BMI categories ( P > .05). The incidence of side effects was also similar across BMIs ( P ≥ .06). Subjects were less likely to feel very or extremely uncomfortable after regadenoson vs adenosine in all groups with BMI ≥ 25 kg/m, but this trend was not statistically significant in subjects with BMI 20-24 kg/m ( P > .05). PRC was inversely related to BMI with 19% higher PRC in the underweight and 36% lower PRC in the extremely obese compared with a normal weight subject. Conclusions: BMI does not alter the efficacy of regadenoson MPI despite lower PRC in high BMI subjects, or its side effect profile despite higher PRC in low BMI subjects. Regadenoson is better tolerated than adenosine but this benefit seems to lose statistical significance in subjects with BMI < 25 kg/m. [ABSTRACT FROM AUTHOR]