血管内超声显像指标对冠状动脉中度狭窄病变功能意义的判断价值

目的:评估血管内超声显像(intravascularultrasound,IVUS)测定的指标对冠状动脉中度狭窄病变功能意义的判断价值。方法:46支冠状动脉造影(coronaryarteryangiography,CAG)显示中度狭窄(直径狭窄率40%～60%)的冠状动脉,压力导丝测定心肌血流储备分数(myocardialfractionalflowreserve,FFRmyo),IVUS测定面积狭窄率及最小管腔面积。以FFRmyo<0.75为界限值,采用受试者工作特征曲线(receiveroperatingcharacteristic,ROC)选择IVUS测量的每个指标的截断点。结果:46支血管病变的直径狭窄率(49±11)%,FFRmyo为(0.83±0.15),显著低于正常组(FFRmyo为0.97±0.02)。14处(30%)病变低于界限值(FFRmyo<0.75)。IVUS面积狭窄率与FFRmyo呈负相关(r=-0.68,P<0.001)。以FFRmyo<0.75为界限值,根据ROC分析,面积狭窄率≥65%为截断点,灵敏度=100%,特异性=72%。最小管腔面积与FFRmyo呈正相关(r=0.63,P<0.001),以最小管腔面积≤4mm2为截断点,灵敏度=93%,特异性=77%。结论:IVUS测定的面积狭窄率≥65%、最小管腔面积≤4mm2,能较准确地判断中度狭窄病变的功能意义。

Intravascular ultrasound criteria for the assessment of the functional significance of intermediate coronary artery stenosis

Objective:to evaluate the role of intravascular ultrasound(IVUS) in the assessment of functional significance of the intermediate lesion.Method:In 46 lesions of intermediate severity(e.g,40% to 60% diameter stenosis)we assessed 1. by pressure wire:myocardial fractional flow reserve(FFR myo,index of functional significance),and 2. by IVUS:minimal lumen cross_sectional area(MLA) and percent area stenosis at the lesion site.Receiver operating characteristic(ROC) curve analysis was performed to establish the best cut_off values of IVUS indexes(i.e.,MLA and percent area stenosis) that were most predictive of FFR myo<0.75.Result:FFR myo in 46 lesions of angiographic intermediate stenosis(49±11)% was significantly lower than it was in angiographic normal artery (0.83±0.15 vs. 0.97±0.02,P<0.01).Fourteen lesions (30%) were functionally critical(e.g, FFR myo <0.75).By regression analysis,percent area stenosis had a significant inverse correlation with FFR myo(r=-0.68, P<0.01).MLA showed a significant positive relation with FFR myo(r=0.63,P<0.01).By ROC analysis,we identified a IVUS area stonosis ≥65%(sensitivity 100%,specificity 72%),a minimal lumen cross_sectional area ≤4 mm +2(sensitivity 93%,specificity 77%) to be the best cut_off values to fit with FFR myo<0.75.Conclusion:IVUS area stenosis ≥65% and minimal lumen cross_sectional area ≤4 mm +2 reliably identified functionally critical intermediate coronary stenosis.