Kawasaki disease (KD) is a systemic vascular inflammatory syndrome of unknown etiology, often associated with coronary artery lesion (CAL) such as coronary artery dilation and coronary artery aneurysm. The incidence of KD in China is increasing year by year, and the epidemiological survey of hospitalized children with KD in Shanghai, such as Huang Guoying, from 1998 to 2002, found that the incidence rate was 16.18/100,000 to 36.18/100,000 within 5 years of age; the incidence of cardiovascular damage was 25.4%, of which coronary artery dilatation accounted for 68%, followed by coronary artery aneurysm accounting for 10%. Thus the disease has now become a major cause of acquired heart disease in children. The clinical efficacy of high-dose intravenous immuneglobulin (IVIG) for the treatment of KD is positive, but a single dose of high-dose IVIG for KD will increase blood viscosity and increase the risk of thromboembolism. In order to evaluate the efficacy of IVIG and to explore the best treatment plan in accordance with the principle of benefit/value ratio, we conducted a retrospective analysis on the incidence of high-dose IVIG treatment and coronary artery lesions in KD in Shanghai from 1998 to 2008. Subjects and methods I. Study subjects and diagnostic criteria Referring to the Japanese epidemiological survey protocol, a uniform questionnaire was developed by the Shanghai Pediatric Cardiovascular Group to retrospectively analyze the clinical data of hospitalized KD patients in Shanghai from 1998 to 2008. A total of 1952 cases of KD patient data forms were collected, of which 1682 cases fully met the requirements, 1064 cases (63.3%) in males and 618 cases (36.7%) in females; age of onset: 2.57±2.33 years (0.1-18.8 years); among them, 2.57±2.32 years in males and 2.57±2.33 years in females; among them, 490 cases under 1 year old ( 29.1%). The diagnosis of typical KD was based on the 2002 revised criteria issued by the Japanese Ministry of Health and Welfare; incomplete Kawasaki disease was defined as those with only 4 or 3 symptoms out of 6, if coronary artery aneurysm was confirmed by echocardiography or cardiovascular angiography; or in children younger than 1 year of age, significant coronary arteritis and coronary artery wall echogenicity enhancement were found, which could also be diagnosed after excluding other diseases. Diagnostic criteria for KD combined with coronary artery lesions: (1) coronary artery endothelial echo enhancement on echocardiography; (2) coronary artery dilation: ≥2.5mm in coronary arteries <3 years old, ≥3.0mm in coronary arteries 3-9 years old, and ≥3.5mm in coronary arteries 9-14 years old; (3) coronary artery aneurysm (CAA): coronary artery dilation of different shapes with an internal diameter of 4-7mm; (4) giant coronary artery aneurysm (GCAA): coronary artery internal diameter: ≥8 mm. II. Treatment regimen The IVIG regimen for the treatment of KD was: 1. 1g/kg×1 time (228 cases); 2. 2g/kg×1 time (568 cases); 3. 0.4-0.5g/kg×5 times (201 cases); 4. 1g/kg×2 times (484 cases); 5. 2g/kg×2 times (7 cases); 6. Others (45 cases). Another 149 patients with KD were not treated with IVIG. All patients were treated with aspirin 30 to 100 mg/kg.d. According to the morbidity characteristics of KD this study distinguished the application time of IVIG as 1, within 5 days of illness; 2, 5-10 days of illness; 3, more than 10 days of illness and no application of IVIG. III. Statistical methods Statistical analysis was performed using SAS 6.12 statistical package. Count data were calculated by X2 test; measurement data were expressed as x±s and t test was used; P<0.05 was considered statistically significant difference. Results I. Correlation between the incidence of coronary lesions and different treatment regimens of IVIG Among the KD patients with IVIG, the incidence of coronary lesions (CAL) was the lowest among those who applied regimen 4 (1 g/kg×2 times) within 5-10 days of the disease course (12.06%), and the difference was statistically significant (P<0.05), as shown in Table I; while the application of regimen 1 (1 g/kg×1 time) within 5-10 days of the disease course was also a kg×1 time) was also a good regimen with a 15% incidence of coronary lesions, second only to the former. In contrast, the incidence of CAL in the regimen 1 to 4 groups with IVIG applied over 10 days of disease was higher than that in all other time periods, and even higher than that in the group without IVIG; while the highest incidence of CAL was 61.54% (P<0.05) in regimen 6 applied within 5 to 10 days of disease. DISCUSSION: Intravenous high-dose IVIG single injection therapy is widely used in the treatment of KD, but since a single dose of high-dose IVIG therapy will abruptly increase blood viscosity, thus increasing the risk of thromboembolism [2], and IVIG is expensive with limited drug availability, and China is still a developing country, it is particularly important to evaluate the appropriate dose of IVIG in the treatment of KD. the main pathological changes are systemic medium and small arteritis, and the most serious hazard is coronary artery damage (CAL), the incidence of CAL is about 25%, which is the most important factor affecting the prognosis of KD. Therefore, it is helpful to evaluate the appropriate dose of IVIG from the perspective of the study of different IVIG and CAL incidence in KD patients for the treatment and prognosis of KD. It is currently believed that the mechanism of IVIG for the treatment of KD: 1) closes the IgFc receptors on the surface of monocytes, platelets, and vascular endothelial cells in the blood, thus blocking the immune reaction between IgFc segments and IgFc receptors; 2) reduces the secretion of lymphokines by activated T cells; 3) reduces antibodies against endothelial cells by inhibiting antibody production; 4) inhibits the PDGF-PDGF receptor pathway activation, thus preventing and controlling vascular damage. Since IVIG has the above mechanism of action, its treatment of KD can rapidly reduce fever, eliminate acute phase symptoms, and reduce the incidence of CAL. In the 1980s, the dose of IVIG was 0.4-0.5g/kg x 5 doses, and Newbugger et al. used a 2g/kg x 1 dose regimen in 1991 to demonstrate better efficacy than split dosing and lower incidence of CAL. The incidence of CAL was higher in those who applied IVIG 2g/kg. In 1999, Li Yongbai et al. reported that there was no statistically significant difference between the effect of IVIG 1g/kg×1 time and 2g/kg×1 time in the treatment of KD, and this study has actively explored for the development of the best treatment plan for KD in accordance with China's national conditions. 2006, Qin Lijun et al. reported that the treatment of 242 KD patients with IVIG found that both 1g/kg×1 time and 2g/kg×1 time could In 2007, Du Zhongdong et al. confirmed that a single dose of 2 g/kg IVIG could more effectively reduce the incidence of CAL; while Sakata concluded that a single dose of 1 g/kg IVIG was more effective in treating KD. Due to differences in study sample sizes, the appropriate dose of IVIG for KD is still controversial in China, so there is an urgent need for multicenter, randomized controlled clinical studies with larger samples to further validate the appropriate dose of IVIG. In this study, we pooled the data of children with KD hospitalized in 50 secondary and higher hospitals providing pediatric medical services in Shanghai from 1998 to 2008, and found that the incidence of coronary artery lesions was the lowest 12.06% (P<0.05) in those who applied regimen 4 (1g/kg×2 times) during the 5-10 days of KD disease course, and the difference was statistically significant; for the incidence of various different doses of IVIG In the comparison of CAL, IVIG at 1g/kg×1 time within 5-10 days of disease duration is still a good choice, and its CAL incidence is only 15%; it is very suitable in the current situation of shortage of medical resources in China. In this study, we found that the incidence of CAL was highest in the IVIG group applied after the duration of KD more than 10 days in most treatment regimens, which may be due to the following reasons: 1. Most of these KD children are incomplete KD or KD with delayed diagnosis, and such KD patients often have high-risk factors for concomitant CAL, in line with Harada's high-risk score, so even with the treatment of IVIG applied, their KD The incidence of concomitant CAL is still the highest; 2. At more than 10 days of KD disease, all types of inflammatory factors and vascular damage factors have been released in large amounts in children, and medium and small vascular lesions have occurred, leading to a high incidence of CAL. This study also found that in scenario 6, i.e., irregular IVIG use its CAL incidence was the highest in all groups, reaching 61.54%; this suggests that irregular application of IVIG is quite a dangerous practice for the prognosis of KD. CONCLUSION: The present 10-year epidemiological survey of hospitalized KD in Shanghai showed that a dose of IVIG 1 g/kg × 2 times during the 5-10 days of KD disease helped to minimize the incidence of CAL in KD patients. Considering the vast size of China and the large urban-rural differences, combining a multicenter, large sample survey in northern and mainland China would help to obtain more precise conclusions.