Kamon Imai

Significantly lower incidence of early definite stent thrombosis of drug-eluting stents after unrestricted use in Japan using ticlopidine compared to western countries using clopidogrel: a retrospective comparison with western mega-studies.

BACKGROUND AND OBJECTIVES The incidence of definite stent thrombosis (ST) after use of drug-eluting stents (DES), as defined by the Academic Research Consortium, is known to be lower in Japan than in western countries. However, a statistical difference in the incidence of early definite ST (EDST) associated with the unrestricted use of DES has not yet been documented. Therefore, the incidence of EDST in our Japanese institute after unrestricted use of DES was retrospectively compared with those reported in western mega-studies. METHODS AND RESULTS During the 40 months from August 2004 to November 2007 (before approval of clopidogrel in Japan), DES were implanted in 3605 lesions in 1885 patients in our institute; lesion- and patient-associated percentages of DES use were 95.2% and 94.7%, respectively. Mean stent length per lesion was 33.2 mm, emergent procedures and ST-elevation myocardial infarctions made up 33.7% and 16.4% of the procedures, respectively, intravascular ultrasonography was used 96.0% of the time, a distal protection device for acute coronary syndrome was used 68.7% of the time, and the mean maximum inflation pressure was 19.5 atm. EDST was observed in five lesions (0.139%) in four patients (0.212%). The incidence of patient-associated EDST at our center was significantly lower than in four western mega-studies (0.736%, 66 of 8970 patients; 0.634%, 149 of 23,500; 0.595%, 52 of 8402; 0.997%, 20 of 2006) (p<0.05, <0.01, <0.05, <0.01, respectively, using a chi(2)-test). CONCLUSION Due to differences in procedural approaches in Japan, the incidence of EDST after unrestricted use of DES was significantly lower than in western countries.

Retrospective comparison of clinical and angiographic outcomes after primary stenting using sirolimus-eluting and bare-metal stents in nonrandomized consecutive 568 patients with first ST-segment elevated myocardial infarctions

BACKGROUND AND PURPOSE The long-term safety and efficacy of primary stenting using drug-eluting stents (DES) in patients with ST-segment elevation myocardial infarction (STEMI) are not fully understood in Japan. Therefore, we retrospectively examined the midterm clinical and angiographic outcomes in STEMI patients after primary stenting using sirolimus-eluting stents (SES) in a clinical setting through a historical comparison with those of bare-metal stents (BMS). METHODS AND RESULTS The study design was a retrospective, nonrandomized, and single-center study. The clinical outcomes for 568 consecutive patients who presented within 12 h of their first STEMI and who were treated with BMS (n = 198; 184 STEMIs from June 2003 to August 2004 and 14 STEMIs from September 2004 to May 2007) or SES (n = 370; from August 2004 to May 2007) at our medical center in Japan were retrospectively investigated in February 2010. The incidence of post-discharge events (comprising cardiac death and nonfatal recurrent MI) after SES placement (3.9%) was not significantly different from that after BMS placement (6.7%). SES was not related to the risk of post-discharge events (mean follow-up for SES, 1327 ± 415 days; BMS, 1818 ± 681 days) (hazard ratio of 0.369 at 95% CI, 0.119-1.147, p = 0.085). The incidence of definite stent thromboses after SES placement (0.54%) was not significantly higher than that after BMS placement (0%). The incidence of binary in-stent restenosis (% diameter stenosis of more than 50% at secondary angiography) after SES placement (8.3%) was significantly lower than that after BMS placement (25.7%; p < 0.001). CONCLUSIONS From the present historical comparison of SES and BMS, we conclude that primary stenting using SES in a clinical setting has favorable clinical and angiographic outcomes in Japanese STEMI patients.

A case of myasthenia gravis with cardiac fibrosis and easily provoked sustained ventricular tachycardia

A 65-year-old male, who had been diagnosed to have myasthenia gravis (MG) 25 years previously, was admitted to our hospital with faintness. Cardiac ultrasonography showed decreased left ventricular function. Magnetic resonance imaging depicted delayed contrast enhancement in localized regions. No significant coronary artery stenosis was found, and due to the reproducible susceptibility for sustained ventricular tachycardia, he underwent cardioverter-defibrillator implantation. Although relatively uncommon, cardiac manifestations should not be overlooked in MG patients, as they may be associated with ventricular arrhythmias and cardiac dysfunction.

Efficacy of simultaneous function and perfusion imaging on Tc-tetrofosmin myocardial scintigraphy

The aim of this study was to determine whether the diagnosis for coronary artery disease (CAD) with 99mTc-tetrofosmin (Tf) myocardial scintigraphy was improved by the combination of function image and perfusion image as compared with perfusion alone. Tf myocardial scintigraphy was performed with one-day protocol (stress/rest) in 51 patients (CAD: 32, Non-CAD: 19) without previous myocardial infarction. Function image was obtained by first pass method, and perfusion image by SPECT. Number of diseased vessels was 14 in right coronary artery (RCA), 18 in left anterior descending (LAD), and 12 in left circumflex (LCX). Ischemia was diagnosed by 2 different parameters 1) perfusion image alone, 2) combination of perfusion image and regional ejection fraction (rEF). On perfusion image, accuracy was 53%, 94% and 86% in RCA, LAD, and LCX respectively. On perfusion + rEF, accuracy was 76%, 90% and 84% in RCA, LAD, and LCX respectively. Specificity in RCA was 45% on perfusion, 84% on perfusion + rEF. Sensitivity in RCA was 77% on perfusion, 54% on perfusion + rEF. LAD and LCX did not change by the addition of function image. By addition of function image, accuracy and specificity of diagnosis in area of RCA improved significantly (p < 0.01). Thus the addition of function image in Tf myocardial scintigraphy would be useful to improve the diagnosis, especially in region of RCA.