腺苷负荷试验心肌灌注显像在老年人冠心病中的临床应用

Clinical application of adenosine myocardial perfusion imaging for detecting coronary artery disease in the elderly

目的评价腺苷负荷试验心肌灌注显像在诊断老年人冠心病的准确性及临床应用的特点。方法63例临床疑诊冠心病或已诊断但病情不稳定需介入治疗老年患者，住院后分别行腺苷负荷试验心肌灌注显像和冠状动脉（冠动）造影检查。腺苷负荷试验心肌灌注采用单光子发射断层显像图像采集系统，腺苷以140μg·kg^-1·min^-1静脉注射，用药时间6min，注射过程中全程监测心电图、血压及患者的症状。于注射腺苷3min末，静脉注射核素显像剂^99mTc—MIBI925 MBq，1．5h后行心肌灌注断层显像，若显像异常，次日行静息心肌显像。冠脉造影按常规程序，在腺苷负荷试验心肌灌注显像前后1周内进行。结果63例中，53例冠脉造影阳性，10例阴性，而腺苷负荷试验心肌灌注显像51例阳性，7例阴性。腺苷负荷试验心肌灌注显像诊断老年人冠心病的总体敏感性为96．2%，特异性为70．0％，阳性预测值94．4％，阴性预测值77．8％，准确性为92．1％。53例冠脉造影显示，冠脉狭窄病变中，单支病变29例，二支14例，三支10例；累及左前降支（LAD）44支，左回旋支（LCX）18支，右冠脉（RCA）25支。腺苷负荷试验心肌灌注显像判断血管病变以LAD敏感性最高，达到95．5％；RCA次之，为84．0％；LCX最差，仅为55．6％；但特异性可达100％。监测过程中，32例（50．0%）患者发生胸闷、胸痛、头晕、头痛等不良反应，无严重事件发生。结论腺苷负荷心肌灌注显像诊断老年人冠心病的敏感性、特异性高，尤其对探查和定位严重的冠脉病变准确性更高；腺苷负荷试验过程中副作用小，且因检查无创，因此在老年人冠心病的临床诊断应用中具有重要的价值。

Objective To analyze the diagnostic accuracy and safety of adenosine stress 99m Tc- MIBI myocardial perfusion single photon emission computed tomography （SPECT） for assessing coronary artery disease（CAD） in the elderly. Methods 63 elderly patients （≥65 years old） without myocardial infarction were enrolled in the research. They were admitted into hospital because of suspected CAD or suffering from acute coronary syndrome. Adenosine was infused intravenously at a rate of 140 μg · kg^-1· min^-1 for 6 minutes. During the period, all patients were given electrocardiogram monitor and blood pressure detection, the uncomfortable symptoms were recorded. At the end of 3 minutes of adenosine infusion, 925MBq of 99mTc-MIBI was injected intravenously. Then adenosine stress SPECT myocardial imaging acquisition was obtained. If the results were abnormal, the rest SPECT myocardial imaging would be performed next day. All patients underwent coronary angiography （CAG） within 1 week before or after SPECT. Results In the 53 CAD patients diagnosed by CAG, there were 51 cases with positive adenosine 99mTc-MIBI myocardial perfusion SPECT. In 10 cases with normal CAG there were 7 cases with negative adenosine myocardial imaging. The results showed the sensitivity, specificity and accuracy of adenosine stress SPECT in detection of CAD in comparison with CAG were 96.2%, 70. 0%, 92.1% respectively. The results of CAG also showed that 74 coronary arteries had been affected （defined as ≥50 % coronary vessel lumen reduction）. There were 44 cases with affection in left anterior descending （LAD）, 18 cases in left circumflex （LCX） and 25 cases in right coronary artery（RCA）. Correspondingly, there were 42 patients with lowering myocardial perfusion in anterior wall territory, 10 patients in lateral wall territory and 21 patients in inferior wall territory. The sensitivity of adenosine 99mTc-MIBI myocardial perfusion SPECT for diagnosing LAD lesion was 95.5%, which was higher than for the other 2 coronary arteries, but the specificity for detecting LCX lesion was 100%. The adverse effects during the adenosine stress test were found in 50% patients, no serious events occurred. Conclusions Adenosine stress 99mTc-MIBI myocardial perfusion SPECT is a good noninvasive method with high diagnostic accuracy and safety in detection of CAD in the elderly, especially, highly accurate for detection and localization of significant CAD.