Role of Anti-Endothelial Cell Antibody in the Development of Coronary Arterial Lesions in Kawasaki Disease

BACKGROUND AND OBJECTIVES : Anti-endothelial cell antibodies (AECA) are found in the sera of many patients with Kawasaki disease (KD). In this study, the pathogenic role of AECA in the development of coronary arterial lesions of KD was investigated. SUBJECTS AND METHODS : Serum IgM-AECA concentrations were measured in 22 KD patients. Cultured human coronary artery endothelial cells (HCAEC) were incubated with either acute or convalescent phase sera, and their expressions of intercellular adhesion molecule-1 (ICAM-1) assessed. IgM fractions of the sera were purified, and their ability to induce ICAM-1 mRNA and protein expressions evaluated. To address the signal transduction pathways involved in IgM-AECA-induced ICAM-1 expression, the blocking effect of four protein kinase inhibitors, PD98059, SB203580, dimethylaminopurine (DMAP) and parthenolide were measured. RESULTS : IgM-AECA was present in 14 out of 22 (64%) acute KD sera. ICAM-1 expression of HCAEC incubated with acute KD sera (117.1+/-46.7) and AECA-positive acute KD sera (143.3+/-37.5) were significantly higher than those of the convalescent KD sera (88.9+/-14.4, p<0.05) or AECA-negative acute KD sera (71.2+/-11.8, p<0.05), respectively. IgM-AECA from KD patients significantly induced ICAM-1 protein and mRNA expression. The upregulation of ICAM-1 expression was significantly inhibited by SB203580, DMAP and parthenolide, but not by PD98059. CONCLUSION : IgM-AECA was detected in the sera of about 2/3 of acute KD patients, which activated endothelial cells by upregulation of ICAM-1 expression, possibly via p38, JNK MAPK and NF-kappaB signal transduction pathways. Thus, IgM-AECA may play a pathogenic role in the development of coronary arterial lesions in KD patients.

Correlations between Coronary Flow Reserve and the Presence of Viable Myocardium after Acute Anterior Myocardial Infarction

BACKGROUND: Coronary flow reserve (CFR) was defined as the ability to increase coronary blood flow maximally in response to demand. The presence of viable myocardium in an infarcted zone indicates the presence of an intact microvasculature. We hypothesized that coronary flow reserve, which assesses the microcirculation, might be associated with the presence of viable myocardium. METHODS: Thirty seven patients with acute anterior myocardial infarction (mean age 55+/-10, 25 males) were enrolled and abnormal 127 segments were analyzed. Dobutamine stress echocard-iography (5 to 20 g/kg/min) was performed before coronary angiography (6+/-3 days after acute myocardial infarction (AMI)). Coronary flow reserve in infarct-related artery was measured at distal site to lesion immediately after successful angioplasty (7+/-2 days after AMI, with residual stenosis less than 20%) by using intracoronary Doppler flow wire. And follow-up 2-dimentional transthoracic echocardiography was performed in 26 patients during 333+/-161 (range of 109-780) days after acute myocardial infarction. Improvement of wall motion at least one segment by one more grade in dobutamine stress echocardiography was defined as contractile reserve. Viable myocardium was defined as the improvement of wall motion in transthoracic echocardiography during follow-up periods. RESULTS: In 26 patients, viable myocardium was detected in 19 patients (73%) and their mean CFR was 1.74+/-0.42, which was significantly increased than 1.16+/-0.14 of CFR of patients without viable myocardium (p<0.001). The agreement of CFR score and presence of viable myocardium in AMI was excellent when CFR was above 1.3 (Area under the curve was 0.906 in receiver operating characteristic (ROC) curve). Sensitivity and specificity to detect viable myocardium in CFR more than 1.3 were 84% & 85% respectively. CONCLUSION: CFR was increased in patients with viable myocardium, and the cut-off value of CFR more than 1.3 was agreed excellently to detect viable myocardium.

Left Atrial Dissection after Mitral Valve Replacement Demonstrated by Transesophageal Echocardiography

Left atrial dissection is one of extremely rare complications associated with mitral valve surgery. We reported a case of left atrial dissection, which was developed after mechanical mitral valve replacement and was demonstrated by transesophargeal echocardiography. The cause of dissection was due to excessive traction of left atrial endocardial layer during surgery.

Adenosine Triphosphate Stress Echocardiography

BACKGROUND: Stress echocardiography have been emerged as an important non-invasive diagnostic tool to detect coronary artery disease. Previous studies indicated that adenosine triphosphate(ATP) is a potent coronary vasodilator as adenosine, the time of action onset and half-life is shorter than dipyridamole, the duration of adverse effect is transient and the use of aminophylline is not needed when side effects develop. The purpose of this study was to evaluate the feasibility and diagnostic accuracy of ATP stress echocardiography in patient with suspected coronary artery disease. METHOD: We investigated 20 patients(mean age 56+/-11, male 11, female 9) who underwent stress echocardiography with ATP infusion(0.15 mg/kg/min for 4 min) and quantitative coronary angiography(QCA). The digitized echocardiographic images were analyzed using wall motion score(1: normal, 2: hypokinesia, 3: akinesia, 4: dyskinesia) in 16 segments. Positivity of ATP stress echocardiography was based on the detection of transient regional wall motion abnormality. The hemodynamic changes and occurrence of adverse effects was carefully monitored. RESULTS: Forteen out of 20 patients had coronary artery disease(>50% diameter stenosis by QCA). Nine out of 14 patients had transient regional wall motion abnormality at coronary artery disease territory(sensitivity 64%). The mean wall motion score index in patients mth positive test was 1.01+0.01 at base and 1.20+0.08 during ATP infusion(p<0.05). Six out of 20 patients who had no regional wall motion abnormality had no coronary artery disease (specificity 100%) with overall diagnostic accuracy of 75%. ATP stress echocardiography showed good agreernent with QCA(kappa value 0.52). Side effect profile revealed chest pain in 6 patients(30%), facial flushing in 3 patients(15%), Wenchebach type AV block in 2 patients(10%) and significant ST-segrnent depression in 1 patients(5%). The mean heart rate, mean systolic and diastolic blood pressure, and mean rate-pressure product were not changed significantly. CONCLUSION: ATP stress echocardiography is feasible and has a diagnostic value similar to that of adenosine and dipyridamole for detecting coronary artery disease with low cost. In addition, it may have minimal side effects and insignificant clinical consequences.