Evidence of pharmacologic preconditioning during PTCA by intravenous pretreatment with ATP-sensitive K+ channel opener nicorandil

Background It is not known whether pretreatment with nicorandil, an ATP-sensitive K+ channel (KATPchannel) opener, induces a preconditioning effect independent of increased collateral recruitment. Methods Forty-four patients with angina who underwent percutaneous transluminal coronary angioplasty (PTCA) to proximal left anterior descending artery (LAD) stenosis were randomly allocated for pretreatment with an intravenous injection of 80g/kg nicorandil 5min before initial ballooning (n=22) or saline (n=22). 99mTc tetrofosmin was injected during balloon inflation, quantitative analysis of occlusion images by SPECT was conducted, and the defect severity score (SS) was calculated. An ECG was recorded during the 2-min inflation to calculate the sum of ST elevation (ΣST). Results ΣST levels were significantly reduced in patients with nicorandil pretreatment compared with control patients (control:1.89±0.85mV nicorandil:1.24±0.57mV, p=0.0052). However, no difference was observed in defect severity (control: 79.0±32.5, nicorandil: 98.7±48.9 ns). A close correlation was observed between SS and ΣST in both groups (nicorandil group R2=0.505, control group R2=0.599). A multivariate regression model demonstrated that both defect severity (p