第一節 研究材料
We studied children who were seen during the acute phase of KD and followed up at Kaohsiung Veterans General Hospital. All children met the criteria for KD previously defined [11]. These KD children with a history of documented CAA are recruited. Exclusion criteria included that children diagnosed as having KD within 12 months of the study, infectious diseases, chronic inflammatory disease, malignancy, and clinical evidence of heart failure. We comprised 11 KD children with CAA referred to as the study group ( 8 males and 3 females) with a mean age of 12.90 ± 2.50 years (age range, 9.25 to 16.67 years), 6.25 to 15.75 years after acute KD (mean 10.77 ± 3.01 years), which had occurred at 0.67 to 6.33 years of age (mean 2.13 ± 1.53 years)(Table 1). Five patients had mild coronary aneurysms, four had moderate aneurysms and two had giant aneurysms during the acute stage. Four patients still had persistent CAA at the time of the present study. We also studied 11 healthy age- and gender-matched children referred to as the normal control group with a mean age of 12.97 ± 2.45 years (age range, 9.33 to 16.67 years)(Table 1). These healthy children were previously discharged from our clinic with a diagnosis of a functional heart murmur and their healthy siblings. This study was approved by the ethics committee of Kaohsiung Veterans General Hospital. Informed consent for the research protocol was obtained from their parents of all subjects and themselves.
第二節 研究設計與進行方法
Study protocol
From the medical records, the following patient data were retrieved: interval from disease onset to time of study, coronary complications, cardiac symptoms, and medications at the time of study. Coronary aneurysms were documented by serial two-dimensional echocardiography. The participants were categorized into two groups for comparisons. Study group comprised KD patients with a history of CAA, and control group comprised healthy age- and gender-matched subjects. The study group received oral simvastatin 10 mg single dose per day at bedtime for three months.
Lipid profiles (LDL-C, HDL-C, TG, TC), hs-CRP, IMT, ASI, baPWV, ABI and FMD were performed during each visit at baseline and every month until finishing three months therapy. The baseline cardiovascular disorder in study group will be revealed after compare with the control group by these evaluating parameters. The primary efficacy outcome of simvastatin is the change from the baseline value in lipid profiles, hs-CRP, IMT, ASI, baPWV, ABI and FMD. The principal safety was monitored every month by muscle-related enzyme (CPK) and liver enzyme (AST and ALT) measurements and relevant clinical complaints, especially muscle cramps.
Discontinuation criteria included persistent increase of >3-fold the upper limit of normal level in ALT or AST, or >10-fold increase the upper limit of normal level for CK or 5- to 10-fold increases in CK with symptoms.
All subjects participate the study will come for a special visit after an overnight fast.
Assessments of endothelial function, arterial stiffness and blood withdrawal were then performed sequentially, as described subsequently. The assessments of IMT, ASI, baPWV, ABI and FMD were performed as published previously. In summary, all measurements were performed during the morning in a fasting state. All children will
be refrained from alcohol & caffeine-containing beverages and against performing heavy exercise on the day before the examination. All subjects were studied with the supine position in a temperature-controlled room (25 ℃). All measurements were performed by the same observer, unaware of clinical details and the stage of the experiment.
Measurement of IMT and ASI
For IMT, the right carotid artery was similarly imaged using the 7 ~ 15 MHz linear array transducer (Vivid 7; GE Medical Systems, USA) at about 1 cm proximal to the carotid bifurcation. The IMT of the common carotid artery far wall was measured using the electronic calipers of the ultrasound machine as described previously [12].
The average of three measurements was used for subsequent analyses.
The carotid artery stiffness was assessed by calculating the stiffness index as reported previously [4,13]. Briefly, a 7~15 MHz linear array transducer was used to image the right carotid artery at about 1 cm proximal to the carotid bifurcation. The systolic and diastolic diameters were measured between the intima of the near and far walls. The onset of the electrocardiogram R-wave is used to identify end diastole, and the peak of the T-wave reproducibly identifies end systole. Three measurements each of systolic and diastolic diameters were averaged for the calculation of stiffness index according to the formula:
ln (SBP/DBP)/(dD/D),
where ln denotes natural logarithm, SBP systolic blood pressure, DBP diastolic blood pressure, dD the difference between systolic and diastolic diameters, and D the diastolic diameter.
Measurement of FMD
After a 10 to 15 min rest, the brachial artery in the right antecubital fossa was visualized using a 7 ~15 MHz transducer. After an optimal longitudinal image of the
brachial artery wall was obtained, two baseline vessel diameters were measured.
Reactive hyperemia was induced by inflating the blood pressure cuff to 200 mm Hg or at least 50 mm Hg above systolic pressure on the forearm distal to the location of transducer for 5 minutes, and then deflating the cuff. End-diastolic images, concurrent with the onset of the QRS complex on electrocardiogram, were acquired at baseline and 1 minute after cuff deflation. Baseline vessel diameter was calculated as the average of two measurements. The percentage change from the baseline diameter to the value during reactive hyperaemia was calculated to determine flow-mediated dilatation (% FMD) [14].
Measurement of baPWV and ABI
We measured the baPWV and ABI by a previously described noninvasive volume plethysmographic technique (form PWV/ABI, Colin Co., Komaki, Japan) [15,16].
Briefly, the occlusion and monitoring cuffs were wrapped around the brachia and ankles, electrocardiogram electrodes were placed on both wrists, and a microphone was placed on the left edge of the sternum. Pulse wave contours in the four extremities were then simultaneously recorded, and baPWV was determined from the pulse transit time and the distance between the brachial and ankle regions. ABI, which is calculated by dividing ankle SBP by brachial SBP, was evaluated simultaneously.
第三節 統計方法
Analyses were performed using SPSS 11.00 for Windows software. The baseline characteristics of the normal control versus the KD study group were compared by using Student t test for continuous data. Mean values before and after statin therapy in KD group was compared by using the paired sample t test. The mean values after three months treatment versus the normal control was compared by using Student t test. A p value <0.05 was considered statistically significant.