负荷超声心动图与负荷单光子发射计算机断层显像评价冠脉介入术后再狭窄

As application and promotion of percutaneous coronary intervention （PCI） in clinic，restenosis after PCI receives more and more attention. It′s of great significance to find restenosis in early period and take active intervention to improve clinical symptoms and prognosis of patients. The study observed accuracy and feasibility of evaluation of restenosis after PCI with dobutamine stress echocardiography （DSE），and compared with nitroglycerin stress single photon emission computed tomography （SPECT） in order to provide an accurate and feasible method for evaluation of restenosis[1].1　Materials and Methods1.1　SubjectsA total of 39 patients with coronary heart disease admitted in our department of cardiology from Dec 2006 to May 2008 were selected，including 28 cases with stable angina pectoris and 11 cases with unstable angina pectoris. There were 24 men and 15 women with age 42～68 （52.8±2.4） years. Patients with following diseases were excluded： other kinds of cardiovascular diseases，such as mitral valve or aortic regurgitation，diabetes mellitus，severe liver or renal dysfunction，tumor etc.1.2　Apparatus and Methods1.2.1　1.2.1　Apparatus： American HPSONOS 5500 type color Doppler ultrasonic diagnostic equipment with probe frequency 2.0～4.0 MHz was applied. Infusion of dobutamine was controlled by microcomputer infusion pump. Advantax-CLV/DLX large scale digital subtraction angiography machine was used to perform coronary angiography （CAG） and it can measure diameter of coronary arteries.1.2.2　Methods： When undergoing PCI，conditions of left main，left anterior descending （LAD），its margo obtusus branch，first diagonal branch，left circumflex （LCX），and right coronary artery （RCA） were recorded and vascular lesions were counted in every patient before and after treatment. The 28 branches of vessels with lesions were performed with selective pure balloon dilatation technique and 31 branches of vessels with lesions got stenting （13 LAD,7 LCX and 11 RCA），and follow up period was 12 months. When clinically suspected of coronary restenosis or follow up to 12 months，CAG and other measurements were performed again. All patients underwent CAG，and received two-dimensional （2-DE） DSE and nitroglycerin stressSPECT within one week before CAG.DSE： Dobutamine stress was divided into five levels,5μg?kg-1?min-1,10 μg?kg-1?min-1,20μg?kg-1?min-1,30 μg?kg-1?min-1,40 μg?kg-1?min-1，each level maintained for three minutes. Echocardiograms were recorded in every level of load and stress test end of test. Routine 12-lead electrocardiogram （ECG） and blood pressure were recorded. Test termination indicators： ①angina pectoris occurred; ② systolic blood pressure <80mmHg or ≥220 mmHg; ③severe arrhythmia occurred; ④ occurrence of two or more segmental ventricular wall abnormal motion; ⑤ heart rate reached 85% HRmax; ⑥ ST segment descended ≥0.2mV on ECG; ⑦ patients can′t tolerate. Methods for analysis： According to 16-segment left ventricular analytic method recommended by American Society of Echocardiography. Motion of left ventricular wall was estimated by semiquantitative method with visual measurement： one score=motion is normal，motion extent of endocardium is normal; two scores=motion is weaken，motion extent of endocardium is low; three scores=no motion，endocardium has no inward motion or has passive motion; four scores=abnormal motion，endocardium outward bulge during systole period. Two experienced physicians for ultrasonography were responsible for observation of ventricular wall myocardial segmental motion on 2-DE and scored. Diagnostic standard： abnormal ventricular wall segmental motion significantly aggravated or new abnormal ventricular wall segmental motion or apparent angina pectoris occurred were regard as DSE positive result.Nitroglycerin stress SPECT： First,99mTc-MIBI myocardial perfusion imaging was performed in rest. All kinds of nitrates were stopped 24h before measurement， 99mTc-MIBI 20 mCi was infused through ulnar vein in rest and images were collected one hour later. After one day， patients took nitroglycerin 1mg sublingually and changes of blood pressure，heart rate and ECG were monitored，three minutes later the99mTc-MIBI 20mCi was infused through ulnar vein，one hour later，the images were collected. Two experienced physicians of department of nuclear medicine performed analysis and interpretation of images respectively; the myocardial tomographic image of left ventricular was divided into 16 segments[1]，namely anterior wall，side wall，posterior septum and inferior wall were divided into basal segment，middle segment and cardiac apex segment respectively; posterior wall and anterior septum were divided into basal segment and middle segment respectively. According to local radioactivity，myocardial intake 99mTc-MIBI was scored as： normal intake=0，decreased=one score，significant decreased=two scores，defect=three scores. Score of one segment decreased ≥one score compared with before after nitroglycerin intervention was regard as myocardium with lesion.1.3　Statistical processSPSS 11.0 statistical software was used to perform statistical analysis. Numeration data were presented as percentage and chi-square test was used for significant test. P<0.05 was regard as possessing significant difference.2　ResultsComparison of restenosis between pure balloon dilatation group and stenting group： there were nine branches occurred restenosis among 28 vessels with lesions undergoing pure balloon dilatation （32.1%），three branches occurred restenosis among 31 vessels with lesions undergoing stenting （9.7%）。2.1　Dobutamine stress echocardiography（DSE）Among 39 patients，there were 11 DSE positive cases and 28 DSE negative cases，they were shown in Table 1. Therefore，sensitivity，specificity and accuracy of DSE were 75.0%,92.6% and 87.2% respectively for evaluating restenosis of coronary.2.2　SPECTAmong 39 patients，there were 19 SPECT positive cases and 20 SPECT negative patients，they were shown in Table 1. Therefore，sensitivity，specificity and accuracy of SPECT were 83.3%,66.7% and 71.8% respectively.Table 1　Compared with CAG the judgment of vascular restenosis in DSE and SPECTCompared with SPECT，there were no significant differences （P>0.05）in sensitivity （83.3% vs. 75.0%） and accuracy （71.8% vs. 87.2%） ，but there was higher specificity （66.7% vs. 92.6%） in DSE for evaluating restenosis after PCI. Main adverse reactions of DSE were nausea （n=3），dizziness （n=2） and supraventricular premature （n=1）。 All patients relieved after symptomatic treatments. No severe arrhythmias and hypertension occurred.3　DiscussionIt′s of great significance to find restenosis in early period and take active intervention to relieve clinical symptoms and prognosis. There are many methods to diagnose coronary artery restenosis： intracoronary ultrasonic imaging，coronary endoscopes are invasive measurements，their operations are complex and cost is too high for many patients. A part of patients can′t use multislice spiral CT coronary imaging because of its cost and radioactivity. Therefore，it′s very important to develop an accurate，feasible and noninvasive method for finding restenosis.Dobutamine is a synthetic drug of catecholamines，it excites β1 receptor in small dose，increases cardiac contractility and myocardial motion，ventricular wall thicken in systolic period. In large dose，dobutamine mainly excites α receptor and significantly increases myocardial oxygen consumption[2,3]. When no restenosis occurs in coronary arteries，blood supply increases correspondingly，no ischemia occurs and ventricular wall motion doesn′t weaken. When restenosis occurs，stenotic vessels limit increase of blood flow in coronary arteries，influence balance of supply and demand of oxygen in myocardium，then ischemia is induced or aggravated，leading to local myocardial contractility decrease and ventricular wall motion weaken. Segmental abnormal motion induced by dobutamine stress test can provide predictive information for ischemia similar or even better than ST segment descend induced by exercise test. Thus，changes of ventricular wall motion under dobutamine stress can be used to judge coronary restenosis. Exercise or drug stress（99mTc-MIBI SPECT）is a common used method for judgment of coronary restenosis after PCI in patients with coronary heart disease.The present study indicated that compared with SPECT，DSE possessed higher specificity （66.7% vs. 92.6%， P<0.05） for evaluating coronary restenosis after PCI，indicating that DSE was an ideal noninvasive method for diagnosing coronary restenosis. Recent meta-analysis indicated： sensitivity，specificity，positive predictive value and negative predictive value of stress echocardiography were 63%,87%,94% and 43% respectively in diagnosing coronary restenosis[4]. Sensitivity detected in present study（75.0%）was high than that of meta-analysis，it may be that restenosis rate of present study truly was higher than that of meta-analysis. Main adverse reactions of DSE were nausea，dizziness，arrhythmia and anxiety[5]. Non-cardiac symptoms such as nausea，vomiting were very significant when approaching maximum heart rate，some patients occurred blood pressure descending，but hypotension was not associated with extent of coronary stenosis and abnormal segmental ventricular wall motion. These symptoms can usually relieve rapidly after drug withdrawal or symptomatic treatment.On the whole，DSE is accurate and feasible for evaluating coronary restenosis after PCI，and it′s economic and safe.【参考文献】[1]李东野，朱　红，夏　勇，等。 DSE、SPECT检测家猪慢性冬眠心肌的对比研究[J]. 中国超声医学杂志，2004,20（5）：331-334.[2]张　静，肖践明。 多巴酚丁胺负荷超声心动图对存活心肌的评估[J]. 中国心血管病研究杂志，2004,2（10）： 821-823.[3]郑　茵，苏哲坦。 多巴酚丁胺超声心动图检验对可疑冠心病有远期预后的预测意义[J].心血管康复医学杂志，1999,8（3）：95[4]Garzon PP，Eisenberg MJ. Functional testing for the detection of restenosis after percutaneous transluminal coronary angioplasty： a meta-analysis [J]. Can J Cardiol,2001,17（1）：41-48.[5]张技革，杨浣宜，陈立军，等。 多巴酚丁胺负荷超声心动图检测心肌缺血[J]. 中国医学影像技术，2002,18（9）： 895-896.