Abstract 1682: Nicorandil Prevents Microvascular Dysfunction and Myocardial Damage Resulting from Percutaneous Coronary Intervention
Background: Studies suggest that the status of the coronary microvasculature in patients with stable angina pectoris is important in determining long-term outcome. Nicorandil, an ATP sensitive potassium-channel opener, may reduce the incidence of microvascular dysfunction after percutaneous coronary intervention (PCI) by dilating coronary resistance vessels. We examined a novel coronary pressure wire-derived Index of Microcirculatory Resistance (IMR) for evaluating the microvasculature in patients with stable angina pectoris undergoing PCI.
Methods: Intravascular ultrasound (IVUS), fractional flow reserve (FFR), index of microcirculatory resistance (IMR) and blood examination (CK, CK-MB, cardiac troponin (cTn) immediately post PCI and 24hours later) were performed in 62 consecutive patients with stable angina pectoris undergoing PCI. FFR and IMR were measured simultaneously with a single coronary pressure wire. FFR was defined as distal coronary pressure (Pd)/proximal coronary pressure and IMR was defined as Pd/coronary flow (or Pd * mean transit time) at peak hyperemia. Patients were randomized to control (n=29) or nicorandil groups (n=33). In the nicorandil group, nicorandil was intravenously administered as a 6-mg bolus injection just before PCI and as a constant infusion at 6-mg/hour for 24-hours thereafter.
Results: All volumetric IVUS parameters and FFR were similar between the 2 groups both pre and post PCI. However, IMR immediately post PCI and cTn 24-hours post PCI were significantly higher in the control group compared to the nicorandil group (IMR: 34.9±12.1 vs 25.8±9.1 units, and cTn: 0.21±0.13 vs 0.12±0.08 ng/mL, for control vs. Nicorandil, p<0.05 for both). The incidence for cTn elevation more than 5-fold of normal range (>0.20 ng/mL) was significantly larger in control group than nicorandil group (41% vs. 12%, p<0.01). Additionally, the control group showed a closer correlation between plaque volume reduction during stenting as assessed by volumetric IVUS and cTn elevation than the nicorandil group (r=0.55 vs. 0.42, p<0.001 for control vs. nicorandil).
Conclusions: Administration of nicorandil during PCI of patients with stable angina pectoris reduces microvascular dysfunction and myocardial damage.