Intravenous bolus administration of nicorandil improves myocardial perfusion in patients with acute ischemic heart failure

Objectives Intravenous administration of nitrate is commonly used for management of acute ischemic heart failure (AIHF). However, it is not well known that intravenous bolus administration of nicorandil is useful for management of AIHF. The purpose of this study is to evaluate the effects of nicorandil bolus administration on myocardial perfusion in cases of AIHF.

Methods Patients who admitted to coronary care unit with AIHF (n=19) were included in this study. Changes in myocardial perfusion were examined by nicorandil-stress myocardial perfusion imaging (MPI) and two days later rest MPI. In the nicorandil-stress imaging, Tc-99m-sestamibi 600MBq was injected just after 0.2mg/kg nicorandil injection over five minutes and SPECT data were acquired 30minutes later. In the rest MPI, SPECT data were acquired 30minutes later from injection. Rest MPI was performed over two days later from stress MPI. H/M ratio and TDS (evaluated with 17 segments 5-grade assessment) were compared between rest and stress images. Moreover, regional summed defect score (RSDS) (with and without coronary significant stenosis) was compared assessed by coronary angiography.

Results H/M ratio was 1.81±0.51 in the stress images and 1.63±0.44 in the rest images (p<0.01). TDS in the stress images (15±8) was significantly lower than in the rest images (19 ±8) (p<0.001). In the myocardial segments with and without coronary stenosis, RSDS was significantly improved in the nicorandil stress images (RSDS with stenosis: 13 ±7 in the stress image vs. 16±8 in the rest image; RSDS without stenosis: 2 ±3 in the stress image vs. 3±4 in the rest image) (p<0.001).

Conclusions Intravenous bolus injection of nicorandil improves myocardial perfusion not only in the myocardial segments with coronary stenosis, but also in the myocardial segments without coronary stenosis. These results indicate that nicorandil might improve the myocardial microcirculation without regard for coronary stenosis