Ryo Yoshioka

Nicorandil prevents microvascular dysfunction resulting from PCI in patients with stable angina pectoris: a randomised study

AIMS Nicorandil, an ATP sensitive potassium channel opener, may reduce the incidence of microvascular dysfunction after percutaneous coronary intervention (PCI) by dilating coronary resistance vessels. The aim of the study was evaluation of the impact of the administration of intravenous nicorandil on measuring the index of microcirculatory resistance (IMR) in PCI to patients with stable angina pectoris (SAP). METHODS AND RESULTS Intravascular ultrasound (IVUS), fractional flow reserve (FFR), IMR and blood examination (CK-MB), cardiac troponin I (cTnI) immediately post-PCI (and 24 hours later) were performed in 62 consecutive patients with SAP undergoing PCI. FFR and IMR were measured simultaneously with a single coronary pressure wire. IMR was defined as Pd/coronary flow (or Pd* mean transit time) at peak hyperaemia. Patients were randomised to the control (n=29), or nicorandil group (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. All volumetric IVUS parameters and FFR were similar between the two groups both pre- and post-PCI. However, IMR immediately post-PCI and cTnI 24 hours post-PCI were significantly higher in the control group compared to the nicorandil group (IMR: 25.4±12.1 vs. 17.9±9.1 units, and cTnI: 0.21±0.13 vs. 0.12±0.08 ng/mL, for control vs. nicorandil). The incidence for cTnI elevation more than fivefold the normal range (>0.20 ng/mL) was significantly larger in the control group than in the 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 cTnI elevation than the nicorandil group (r=0.55 vs. 0.42, p<0.001 for control vs. nicorandil). CONCLUSIONS In patients undergoing successful coronary stenting for stable angina, administration of nicorandil is associated with reduced microvascular dysfunction induced by PCI.

TCTAP C-024 Spontaneous Coronary Artery Dissection (SCAD)

### Patient initials or identifier number SI ### Relevant clinical history and physical exam A 40-year-old woman with chronic gastritis, no prior cardiac history and no tobacco abuse admitted to our hospital. For over three days, she had frequent episodes of chest oppression on effort, and brief

TCT-451 Impact of Stent Recoil and Fracture in RCA Ostium Restenosis Following Stainless Steel or Cobalt Chromium Drug-Eluting Stent Implantation: A Serial Angiographic and IVUS Study

Background: PCI procedure of RCA ostium stenosis is still a challenging issue due to high stent restenosis rate, possibly due to mechanical stress. However, mechanisms of restenosis following cobalt-chromium everolimus-eluting stent (EES) or stainless steel biolimus-eluting stent (BES) implantation have not been well clarified. Methods: Sixty-fourRCAostium restenosis cases after 2ndgenerationDES (40EESand 24 BES) were retrospectively analyzed. Serial (post initial stent and follow-up as revascularization) angiographic and IVUS evaluation were performed. In quantitative angiographic analysis (QCA), incidence of stent fracture (defined as complete separation of the stent segments and/or the absence of a stent strut on magnified fluoroscopic image), and partial (only one of the inner or outer struts was separated) and complete (both the inner and outer struts were disconnected) fracture type were evaluated. In IVUS, serial changes ofminimum lumen and stent area (SA), and degree of stent recoil atminimum lumen area, defined as (follow-up SA baseline SA / baseline SA*100), were also measured. Results: Average follow-up phase was 14 10-months. Angiographic and IVUS morphometric parameters were similar in both groups at baseline. Significant lumen narrowingwas observed from baseline to follow-up in both groups (10.2 4.6 to 2.5 2.0, 10.7 5.4 to 2.4 2.3 mm2 in minimum lumen area, EES vs. BES, p<0.01 from baseline to follow-up for all). Stent fracturewasmore frequently observed inBES than EES (85 vs. 8%, p<0.01). In addition, complete fracturewas highly observed inBES (29%) compared to EES (2%, p<0.05). In contrast, significant stent recoil was observed in EES only (11.8 5.7 to 9.0 5.4 mm2, p<0.01 from baseline to follow-up for EES, 11.6 4.8 to 11.3 3.4 mm2, p1⁄4ns for BES, and degree of stent recoil was significantly larger in EES than BES (23.8 vs. 2.6%, p<0.05). Additionally, there was only 1 BES and no EES case that both stent fracture and significant recoil, resulting in stent restenosis, was observed. Conclusions: Stent fracture appears to be the major cause of RCA ostium restenosis after stainless steel BES, whereas stent recoil seem to be associated with restenosis after cobalt-chromium EES.