Color of culprit lesion at 6 months after plain old balloon angioplasty versus stenting in patients with acute myocardial infarction

Myocardial Production of Plasminogen Activator Inhibitor-1 is Associated with Coronary Endothelial and Ventricular Dysfunction after Acute Myocardial Infarction

AIM

Although plasminogen activator inhibitor-1 (PAI-1) is abundantly expressed in infarcted myocardium, the pathogenic role of myocardial PAI-1 remains unknown. This study examined whether PAI-1 in the infarcted lesion contributes to coronary endothelial dysfunction and left ventricular (LV) dysfunction in patients with acute myocardial infarction (AMI).

METHODS

Plasma levels of PAI-1 activity and tissue-plasminogen activator (tPA) antigen were measured 2 weeks and 6 months after MI by ELISA in plasma obtained from the aortic root (AO) and anterior interventricular vein (AIV) in 28 patients with a first AMI due to occlusion of the left anterior descending coronary artery (LAD). Coronary blood flow responses in LAD to intracoronary infusion of acetylcholine (ACh) and left ventriculography were measured at the same time points: 2 weeks and 6 months after MI.

RESULTS

The trans-myocardial gradient of PAI-1 from AO to AIV, reflecting production/release of PAI-1 in the infarcted lesion, was inversely correlated with the coronary blood flow response to ACh 6 months after MI (r=-0.43, p=0.02) and with the percentage change in LV regional motion in the LAD territory from 2 weeks to 6 months after MI (r=-0.38, p=0.04). The trans-myocardial gradient of tPA level showed no significant correlations.

CONCLUSIONS

PAI-1 produced in the infarcted myocardium and released into the coronary circulation is associated with endothelial dysfunction in resistance vessels of the infarct-related coronary arteries and with progressive dysfunction of the infarcted region of the left ventricle in AMI survivors.

Vulnerable disease may induce neointimal coverage after sirolimus-eluting stent implantation

BACKGROUND

Neointimal formation can protect against thrombosis after sirolimus-eluting stent (SES) implantation; however, promoters of neointimal formation are unknown.

METHODS

Six-month follow-up angioscopy was performed in 141 consecutive patients with SES implantation. All patients received aspirin (100 mg) and ticlopidine (200 mg) daily until angioscopy. We defined 2 grades of neointimal coverage as follows: insufficient coverage including no or partial neointimal coverage of stent struts, and sufficient coverage. The possible promoters of neointimal formation that were evaluated in this study were the condition of coronary artery disease (stable angina or acute coronary syndrome); angioscopic markers, including visible thrombus and plaque color (white or yellow); serum markers, including low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting blood glucose, hemoglobin A(1c), high-sensitive C-reactive protein, and fibrinogen; blood pressure and smoking; intervention markers, including stent size and length and intravascular ultrasound measurements; and medication, including statins, anticoagulants, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, calcium antagonists, and β-blockers.

RESULTS

Univariate analysis revealed that high-sensitive C-reactive protein, plaque color, and the condition of coronary artery disease were significantly correlated with the grade of neointimal coverage. Multivariate analysis using these 3 parameters revealed that only acute coronary syndrome (vulnerable disease) significantly promoted neointimal coverage.

CONCLUSION

Vulnerable disease may promote neointimal coverage after SES implantation.

Plaque Color Analysis by the Conventional Yellow-Color Grading System and Quantitative Measurement Using LCH Color Space

BACKGROUND

Yellow plaques of higher color grades are regarded as more vulnerable. We tried to elucidate the characteristics of yellow color that are regarded as the sign of vulnerable plaques by an objective and quantitative plaque color analysis.

METHODS

The color of yellow plaques was quantitatively analyzed using LCH color space and was presented by the maximum values of lightness (Lmax), chroma (Cmax), and hue (Hmax). Effect of light intensity on these parameters was experimentally examined (five plaque models, six light intensities). Relation between conventional yellow-color grade and LCH parameters was examined (31 plaques). Color analysis with LCH color space was applied (1) to compare the culprit lesions of unstable angina (eight patients) and of stable effort angina (nine patients) and (2) to evaluate the regression of yellow plaque by 80-week statin treatment (four patients, 19 plaques).

RESULTS

Cmax and Hmax were not influenced by light intensity so far as it was within appropriate range. Cmax (13 +/- 3, 25 +/- 5, and 28 +/- 4) became higher and Hmax (178 +/- 26, 134 +/- 10, and 91 +/- 16) became lower as the grade became higher (P < 0.0001). Culprit lesions of unstable angina had higher Cmax (22.8 +/- 7.9 vs 14.8 +/- 7.5, P = 0.04) and lower Hmax (73.3 +/- 19.7 vs 168.0 +/- 71.5, P = 0.002) than stable effort angina. Statin treatment reduced Cmax (21.3 +/- 9.6 vs 14.6 +/- 3.1, P = 0.004) and increased Hmax (82.6 +/- 25.8 vs 142.3 +/- 54.1, P = 0.0005).

CONCLUSIONS

Plaque color was consistently and quantitatively measurable using LCH color space uninfluenced by light intensity of appropriate range. Vulnerable yellow color had high chroma and low hue, indicating vivid and reddish-yellow color.

Distal Protection Improved Reperfusion and Reduced Left Ventricular Dysfunction in Patients With Acute Myocardial Infarction Who Had Angioscopically Defined Ruptured Plaque

Background— Distal protection, in the Saphenous Vein Graft Angioplasty Free of Emboli (SAFER) trial, is demonstrated to prevent distal embolism in the percutaneous coronary intervention of saphenous vein graft. However, in the Enhanced Myocardial Efficacy and Recovery by Aspiration of Liberated Debris (EMERALD) trial, it was not effective in the percutaneous coronary intervention of native coronary arteries in patients with acute myocardial infarction (AMI). We hypothesized that its effectiveness would be determined by lesion characteristics. Therefore, we classified the type of culprit lesion by angioscopy and examined its influence on the effectiveness of distal protection, comparing patients with AMI treated with and without distal protection.

Methods and Results— Consecutive patients with AMI treated without distal protection (n=110) from July 2000 to July 2002 and those treated with distal protection (n=81) from July 2002 to July 2004 were included. Patients in each group were subdivided according to whether or not they had angioscopically defined ruptured plaque at culprit lesion. Among those groups, incidence of no-reflow phenomenon, ST-segment resolution, myocardial blush grade, and left ventricular ejection fraction at 6 months were compared. Aspirated samples by distal protection were semiquantitatively and histologically analyzed and compared between patients with and without ruptured plaque. No-reflow phenomenon was most frequently ( P <0.05) observed in patients with ruptured plaque treated without distal protection. ST-segment resolution (68±15% versus 40±21%, P <0.001), myocardial blush grade (2.6±0.5 versus 1.8±0.3, P <0.001), and left ventricular ejection fraction (47.2±6.7% versus 41.0±9.7%, P <0.01) were improved by distal protection among patients with ruptured plaque but not among patients without ruptured plaque. Aspirated samples >1 mm were detected more frequently (97.3% versus 78.5%, P <0.05) in patients with ruptured plaque than those without ruptured plaque. Histologically, aspirated samples contained plaque debris (95.3% versus 31.1%, P <0.05) more frequently in patients with ruptured plaque than in those without ruptured plaque.

Conclusions— Distal protection reduced microcirculation damage and left ventricular dysfunction in patients with AMI who had angioscopically defined ruptured plaque. Distal embolization of plaque debris was detected more frequently in patients with ruptured plaque. These results suggest that microcirculation damage and left ventricular dysfunction are increased mainly by distal embolization of plaque debris rather than of thrombus.