Unstable angina and non-ST elevation acute coronary syndrome: epidemiology and current management in Japan (Japan Multicenter Investigation for Cardiovascular Disease-D (JMIC-D) Committee).

BACKGROUND: A multicenter study was conducted to assess the current medical management of unstable angina (UA) and non-ST-elevation acute coronary syndrome in Japan. METHODS AND RESULTS: This study presents the results of a nationwide questionnaire survey of 770 sites and a case report investigation performed at 20 sites. The questionnaire survey revealed that the number of acute myocardial infarction (AMI) patients treated annually was 1.56-fold greater than the number of UA patients. Non-ST-elevation AMI accounted for 17% of all patients with AMI. Analysis of case reports for 885 UA patients showed extensive use of invasive treatment. In the UA patients, the cumulative incidence of a composite endpoint (all-cause mortality, AMI, and urgent coronary revascularization) was 2% at 1 month and 9% at 6 months. Stratified analysis with respect to the composite endpoint through 6 months showed a significantly lower incidence in patients treated with a calcium-channel blocker than in patients not treated with a calcium-channel blocker. CONCLUSIONS: In Japan, fewer patients are hospitalized annually for treatment of UA than for AMI. The largest percentage of UA patients had Braunwald class III disease. Non-ST-elevation AMI is managed in Japan according to the principle of early invasive treatment, resembling the treatment for ST-elevation AMI. The outcome of treatment is better for Japanese UA patients than for Japanese AMI patients.

Myocardial contrast echocardiography assessment of acute changes in collateral perfusion of contralateral coronary artery with coronary flow reserve after coronary angioplasty.

BACKGROUND: Coronary flow velocity reserve (CFVR) is used to evaluate the severity of epicardial and intramyocardial coronary artery disease. Collateral flow to an adjacent compromised myocardial territory may influence the CFVR of a specific artery. METHODS: To assess the impact of collateral flow on CFVR, we measured CFVR and assessed perfusion area (PA) with myocardial contrast echocardiography in the right coronary arteries of 18 patients with total/subtotal occlusion of the left anterior descending coronary artery before and after angioplasty. A total of 10 patients had well-developed collaterals emerging from the right coronary artery (group I) and 8 patients did not (group II). Using a Doppler-tipped guidewire, we measured CFVR, which is defined as the ratio of papaverine-induced hyperemic average peak velocity of coronary flow to baseline. RESULTS: Before angioplasty of the left anterior descending coronary artery, CFVR was significantly reduced in group I compared with group II (2.35 +/- 0.47 vs 3.26 +/- 0.54, P < .01). Baseline average peak velocity in group I before angioplasty was significantly greater than that after angioplasty (23.7 +/- 11.6 vs 19.2 +/- 9.7 cm/s, P < .05). After angioplasty, CFVR immediately increased in group I to 3.46 +/- 0.54 ( P < .001). The increase in CFVR was well correlated with the decrement in PA after angioplasty (r = 0.883, P < .001). CONCLUSION: The CFVR of an artery that supplies extensive collaterals is limited because of an elevation in the baseline resting flow velocity. This restriction in CFVR improves proportionally with decreases in PA that occurs after angioplasty of the ipsilateral coronary artery. These data suggest that PA, in addition to coronary artery structure, influences CFVR.

Assessment of plaque vulnerability by angioscopic classification of plaque color.

BACKGROUND: The disruption of yellow plaque and subsequent thrombosis is regarded as the mechanism of acute coronary syndrome. However, there are limited reports on the assessment of plaque vulnerability. Therefore, we tested whether the angioscopically determined yellow color intensity of plaque is associated with the prevalence of thrombosis on the plaque. METHODS: The angioscopic images of 843 patients who underwent catheterization and angioscopic examination from November 1999 to July 2003 for the diagnosis of coronary artery diseases were analyzed. Suspected culprit vessel was observed by angioscopy, and the yellow color intensity (1, light yellow; 2, yellow; 3, intensive yellow) of all yellow plaques (n = 1253) detected in the nonstenotic (diameter stenosis <50%) coronary segments was determined, as well as whether there was thrombosis on the plaques. RESULTS: The number of detected yellow plaques was 345, 721, and 187 for color grade 1, 2, and 3, respectively. The prevalence of thrombosis detected by angioscopy (15%, 26%, and 52% on the plaque of color grade 1, 2, and 3, respectively, P <.0001) was significantly higher on the plaque of higher yellow color grade. CONCLUSIONS: The yellow color intensity of plaque determined by angioscopy was strongly related with the prevalence of thrombosis on the plaque. The yellow color intensity may be a marker of plaque vulnerability.