静息全周期比值和定量血流分数评价冠状动脉临界病变准确性的对比研究

目的 以血流储备分数（FFR）为金标准，比较定量血流分数（QFR）与静息全周期比值（RFR）评估冠状动脉临界病变的准确性及临床应用价值。方法 回顾性纳入2020年9月至2022年1月，在北京大学第三医院因冠状动脉性心脏病行冠状动脉造影并同时接受FFR和RFR检测的142例患者142支血管病变，分析RFR、QFR与FFR的线性相关性和诊断一致率，并进行受试者工作特征（ROC）曲线分析。根据性别及靶血管进行亚组分析。结果 142例患者年龄66(58,71)岁，87例（61.3%）为男性，110支（77.5%）靶病变位于左前降支，RFR与FFR相关性r=0.814(95%CI 0.748～0.864,P<0.0001)、QFR与FFR相关性r=0.617(95%CI0.503～0.709,P<0.0001)，均存在显著线性相关关系。RFR对应FFR≤0.80的AUC0.786(95%CI0.715～0.857)，而QFR对应FFR≤0.80的AUC 0.707(95%CI0.633～0.782)，两者之间的AUC差异无统计学意义（P=0.056）。在不同性别及靶病变的亚组分析中，...     

瞬时无波形比值与血流储备分数的相关性及其影响因素

目的评价瞬时无波形比值(iFR)与血流储备分数(FFR)的相关性及影响诊断一致性的因素。方法回顾性收集北京大学第三医院2015年5月至2019年4月接受iFR和FFR检测的冠心病患者,探讨二者的相关性及影响其诊断一致性的因素。结果收集60例患者80支冠状动脉的109组FFR和iFR数据,FFR和iFR中位数分别为0.80(0.74,0.85)和0.90(0.87,0.94),二者呈线性相关(r=0.780,P<0.001)。iFR预测FFR≤0.80的受试者工作特征曲线下面积为0.870,最佳临界值为iFR≤0.90,诊断一致率为77.1%。iFR“灰区”为0.88~0.94,可使44.0%的功能学评价免予使用腺苷。体重指数是二者诊断不一致的独立影响因素,与iFR≤0.89且FFR≤0.80组相比,iFR>0.89且FFR≤0.80组的参考血管直径[(3.06±0.75)mm比(2.54±0.67)mm]、最小管腔直径[1.84(1.42,2.21)mm比1.35(1.17,1.52)mm]和最小管腔面积[2.65(1.58,3.83)mm2比1.42(1.08,1.83)mm2]均较大(均P<0.05)。结论iFR与FFR具有良好的相关性,病变局部解剖特点可能对二者的诊断一致性产生一定影响。     

定量血流分数与血流储备分数诊断错配的影响因素研究

目的 探讨定量血流分数（QFR）与血流储备分数(FFR)检查诊断错配的预测因素。方法 回顾性选取2018年6月1日至2023年2月1日就诊于阜外华中心血管病医院行FFR检查的患者进行离线QFR分析,分别以0.80为临界值将符合纳入标准的337例患者分为四组：FFR(+)QFR（+）、FFR(+)QFR（-）、FFR(-)QFR（+）、FFR(-)QFR（-）。比较四组间基线数据、实验室及影像学检查,多因素logistic回归分析探究QFR和FFR诊断错配的预测因素。结果 离线QFR和FFR功能分类的一致率为81.01%,273例病变分类一致,64例病变分类不一致。多因素logistic回归分析显示,FFR≤0.80时QFR错配预测因素为较小的直径狭窄百分比（DS%）(OR=0.837,95%CI 0.774～0.904,P<0.01)和较短的病变长度（LL）(OR=0.931,95%CI 0.893～0.971,P=0.001);FFR>0.80时QFR错配预测因素为较大的年龄（OR=1.055,95%CI 1.003～1.111,P=0.039）、较大的DS%(OR=1....     

定量血流分数对冠状动脉血流动力学的评估价值

目的探讨在血流储备分数(fractional flow reserve,FFR)≤0.80时定量血流分数(quantitative flow ratio,QFR)评估冠状动脉血流动力学的准确性。方法回顾性分析2017年1月12日至2018年3月7日期间在广东省人民医院因怀疑冠状动脉粥样硬化性心脏病(冠心病)而进行冠状动脉造影检查的患者的临床资料,调取出已经进行FFR检查的患者52例,分析人员在盲法下分析血管的QFR与定量冠状动脉造影(quantitative coronary angiography,QCA)的数值。采用Clopper-Pearson计算QFR与FFR的相关性;以FFR为"金标准",计算QFR与QCA的诊断准确率、敏感性、特异性、阳性预测值、阴性预测值。使用SPSS软件,绘制受试者工作特征(receiver operating characteristic,ROC)曲线并计算曲线下面积,探讨QFR在冠状动脉血流动力学方面的临床价值。结果共有52例患者(52条血管)入选了本研究,以FFR的数据为"金标准",QFR的同阴性和同阳性诊断准确率明显高于QCA,差异有统计学意义[83.3%(95%CI:72.2～92.6)vs. 61.1%(95%CI:48.1～74.1),P=0.005]。QFR的敏感性和特异性均高于QCA,差异有统计学意义(敏感性:85.7%vs. 57.1%,P0.05;特异性:87.5%vs.67.7%,P0.05)。QFR的阳性预测值、阴性预测值、阳性似然比和阴性似然比分别为81.8%、90.0%、6.86和0.16;QCA的阳性预测值、阴性预测值、阳性似然比和阴性似然比分别为54.5%、70.0%、1.77和0.63。QFR的ROC曲线下面积大于QCA(66.8 vs. 47.2),提示QFR的诊断效能比QCA更高。Clopper-Pearson计算QFR与FFR之间的相关系数是0.79(P0.01)。结论 QFR和FFR在诊断冠状动脉血流动力学之间有很好的相关性,QFR对冠状动脉狭窄的诊断准确性高于QCA,在冠状动脉血流动力学诊断方面具有临床应用价值。     

冠状动脉临界病变血管内超声检查参数与定量血流分数的相关性研究

目的探讨冠状动脉临界病变血管内超声(IVUS)检查参数与定量血流分数(QFR)的相关性。方法前瞻性连续入选2018年9月至2019年9月于同济大学附属东方医院接受QFR和IVUS检查的116例患者(117处冠状动脉临界病变)。根据QFR评估结果,将患者分为QFR≤0.80组(25处病变)和QFR>0.80组(92处病变),比较两组IVUS检查参数的差异。应用Poisson线性相关性分析以及受试者工作特征(ROC)曲线评估IVUS与QFR的相关性,应用logistic多元回归分析QFR≤0.80的预测因素。结果IVUS检查发现,QFR≤0.80组最小管腔面积(MLA)[(3.1±0.8)mm²比(3.6±1.1)mm²,P=0.040]、最小管腔直径(MLD)[(1.8±0.3)mm比(2.0±0.3)mm,P=0.012]显著小于QFR>0.80组,而斑块负荷[(73.5±5.6)%比(68.0±8.4)%,P=0.002]、面积狭窄率[(69.8±8.8)%比(63.8±9.8)%,P=0.007]、斑块偏心指数[(0.83±0.12)比(0.73±0.19),P=0.008]及回声消减斑块比例(52.0%比23.9%,P=0.003)显著高于QFR>0.80组,差异均有统计学意义。Poisson线性相关分析显示,MLA(r=0.259,P=0.005)、MLD(r=0.300,P=0.001)与QFR正相关,而斑块负荷(r=–0.357,P<0.001)以及斑块偏心指数(r=–0.247,P=0.008)与QFR负相关。logistic多因素回归分析表明斑块负荷>70%(OR 4.531,95%CI 1.443~14.222,P=0.010)和斑块偏心指数(OR 1.066,95%CI 1.014~1.121,P=0.012)为QFR≤0.80的独立预测因素。结论冠状动脉临界病变IVUS检查结果中斑块负荷>70%以及斑块偏心指数是QFR≤0.80的独立预测因子。     

基于冠状动脉CT血管造影的血流储备分数对不同性质冠状动脉斑块患者发生病变特异性缺血的诊断价值

目的分析基于冠状动脉CT血管造影的血流储备分数(CT-FFR)对不同性质冠状动脉斑块患者发生病变特异性缺血的诊断价值。方法连续收集2019年12月至2021年4月在陕西省人民医院心血管内二科住院并接受选择性冠状动脉造影(CAG)检查的35例疑似冠状动脉狭窄患者及2020年7月至2021年4月在四川大学华西医院住院并接受选择性CAG检查的56例疑似冠状动脉狭窄患者为研究对象。根据冠状动脉斑块性质将所有患者分为钙化斑块组(n=14)、非钙化斑块组(n=34)和混合斑块组(n=42)。比较三组人口学资料、入院时心率、入院时血压、既往史、入院时实验室检查指标、CT-FFR及血流储备分数(FFR)。以FFR≤0.80作为诊断病变特异性缺血的“金标准”,绘制ROC曲线以评价CT-FFR对不同性质冠状动脉斑块患者发生病变特异性缺血的诊断价值;采用相关系数分析FFR与CT-FFR诊断不同性质冠状动脉斑块患者发生病变特异性缺血结果的一致性,绘制Bland-Altman图以分析CTFFR与FFR诊断不同性质冠状动脉斑块患者发生病变特异性缺血结果的差异性。结果三组年龄、入院时舒张压、有糖尿病史者占比、有高血压史者占比及入院时血肌酐(Scr)比较,差异有统计学意义(P<0.05)。以CT-FFR≤0.80诊断为病变特异性缺血。在冠状动脉钙化斑块、非钙化斑块、混合斑块患者中,CT-FFR诊断病变特异性缺血的灵敏度分别为55.55%、72.22%、75.00%,特异度分别为20.00%、81.25%、55.55%,正确率分别为42.86%、76.47%、66.67%。ROC曲线分析结果显示,CT-FFR诊断冠状动脉钙化、非钙化、混合斑块患者发生病变特异性缺血的AUC分别为0.40〔95%CI(0.07,0.73),P=0.549〕、0.75〔95%CI(0.58,0.93),P=0.011〕、0.66〔95%CI(0.48,0.84),P=0.080〕。相关性分析结果显示,FFR与CT-FFR诊断冠状动脉钙化、混合斑块患者发生病变特异性缺血结果均无线性关系(冠状动脉钙化斑块患者:R^(2)<0.01,P=0.926;冠状动脉混合斑块患者:R^(2)=0.07,P=0.102),FFR与CT-FFR诊断冠状动脉非钙化斑块患者发生病变特异性缺血结果的一致性良好(R^(2)=0.19,P=0.011)。Bland-Altman图分析结果显示,CT-FFR与FFR诊断冠状动脉非钙化斑块患者发生病变特异性缺血的所有散点基本在平均差值的95%CI内,说明两种方法检测结果差异性小。结论CT-FAR对冠状动脉非钙化斑块患者发生病变特异性缺血具有一定诊断价值,对冠状动脉钙化、混合斑块患者发生病变特异性缺血的诊断价值较低。     

基于冠状动脉CT的血流储备分数在心肌缺血中的诊断应用价值:一项单中心前瞻性研究

目的探讨国产自主研发的基于冠状动脉CT的血流储备分数(CT-FFR)对心肌缺血的诊断价值。方法前瞻性入选2019年11月至2020年5月复旦大学附属中山医院完成冠状动脉CT血管造影检查的心绞痛住院患者。基于冠状动脉CT图像,利用CT-FFR软件来建模计算CT-FFR值。以冠状动脉造影术中导管测定的FFR值为诊断金标准,计算CT-FFR的诊断效能,包括敏感度、特异度、预测值、曲线下面积(AUC)等。采用Pearson相关分析和Bland-Altman图分析两者的相关性和一致性。并且针对临界病变人群和钙化病变人群进行亚组分析。结果入选患者77例。CT-FFR的诊断敏感度为91.4%,特异度为94.7%,阳性预测值为98.1%,阴性预测值为78.2%,准确性为92.2%。CT-FFR用于诊断心肌缺血的AUC为0.96(95%CI 0.91~0.99,P=0.024),最佳诊断界值为0.795。Pearson相关分析显示CT-FFR和FFR的相关性良好(r=0.767,P<0.001),Bland-Altman图显示CT-FFR与FFR具有良好的一致性。在临界病变和钙化病变亚组分析中,CT-FFR也有着类似的诊断效能。结论CT-FFR对心肌缺血疾病的诊断效能接近导管测定的FFR,是一种行之有效的无创检测心肌缺血的手段。     

冠状动脉CT血流储备分数在冠状动脉临界狭窄患者心肌缺血诊断中的应用

目的 评价冠状动脉无创血流储备分数（FFR-CT）对冠状动脉临界狭窄病变（冠状动脉狭窄50%～70%）心肌缺血的诊断效能,为FFR-CT在心肌缺血诊断中的临床应用提供参考。方法 67例冠状动脉临界狭窄病变患者,均行冠状动脉CT血管造影（CTA）及冠状动脉造影检查。患者均行冠状动脉血流储备分数（FFR）检查,根据FFR值评估心肌缺血情况。根据冠状动脉CTA影像数据算出FFR-CT值。采用Pearson相关分析FFR值和FFR-CT值之间的相关性。采用ROC评估FFR-CT对冠状动脉临界狭窄病变患者心肌缺血诊断的效能。结果 67例患者中FFR值≤0.8的有35例,FFR-CT值≤0.8的有26例。FFR值与FFR-CT值呈正相关（r=0.666 8,P<0.01）。共评估血管83支,FFR-CT用于心肌缺血诊断的ROC下面积为0.938(95%CI 0.890～0.985,P<0.01),诊断界值为0.8时,其对心肌缺血诊断的灵敏度87.5%、特异度95.24%、阳性预测值85.29%、阴性预测值79.63%。结论 FFR-CT值对冠状动脉临界狭窄病变患者心肌缺血具有较高的诊断...     

利用血管内超声结果验证定量血流分数对冠状动脉造影临界病变诊断价值的研究

目的:参考血管内超声(IVUS)测量结果,分析定量血流分数(QFR)在评估冠状动脉(冠脉)造影临界病变中的诊断价值。方法:连续筛选南京医科大学第一附属医院2014年1月至2015年1月行冠脉造影的患者,纳入造影诊断冠脉临界病变(靶病变血管狭窄程度40%～70%)、并行IVUS检查的患者57例,共62处病变。使用QFR测量系统对入选的冠脉病变进行分析,参照IVUS测量的最小管腔面积(IVUS-MLA)及面积狭窄率(IVUS-AS)结果,分析冠脉造影临界病变中QFR对血管显著狭窄病变的诊断价值。结果:57例患者的平均靶病变IVUS-MLA为(3.93±1.15)mm~2,IVUS-AS为63.5%±11.8%,IVUS诊断的血管显著狭窄靶病变38例(61.3%);靶病变平均QFR为0.87±0.14。QFR与IVUS-MLA(R=0.477)呈中等程度正相关,与IVUS-AS(R=-0.604)呈较强负相关(P均0.001)。相比QFR0.8的冠脉造影临界病变,QFR≤0.8的病变IVUSMLA更小[(3.04±0.52)mm~2 vs.(4.15±1.16) mm~2,P0.001],IVUS-AS更高(76.03%±5.65%vs. 60.19%±10.79%,P0.001)。分别以IVUS-MLA4 mm~2、IVUS-AS70%诊断血管显著狭窄病变时,QFR的ROC曲线下面积分别为0.822(95%CI:0.717～0.926,P0.001)和0.746(95%CI:0.617～0.876,P=0.001),以QFR≤0.8作为诊断界值,诊断一致性Kappa值分别为0.246(95%CI:0.085～0.407,P=0.007)和0.469(95%CI:0.246～0.692,P0.001),敏感度分别为32.4%和47.8%,特异度分别为96.0%和94.9%,阳性预测值分别为92.3%和84.6%,阴性预测值分别为49.0%和75.5%。结论:QFR对冠脉造影临界病变中管腔面积显著狭窄的病变具有良好的诊断价值。     

纤维蛋白原与冠状动脉临界病变血流储备分数的相关性

目的探讨血浆纤维蛋白原水平与冠状动脉临界病变血流储备分数(FFR)的相关性及其临床意义。方法入选经冠状动脉造影检查为冠状动脉临界病变(冠状动脉狭窄程度为50%~70%)并行FFR检查的患者,根据冠状动脉FFR测得值分为FFR≥0.8组(23例)和FFR0.8组(14例)。入选患者均于入院后检测纤维蛋白原、总胆固醇、甘油三酯、尿酸、肌酐、血糖等指标。采用相关分析和ROC曲线分析纤维蛋白原与FFR的相关性。结果应用偏相关分析控制可能影响纤维蛋白原及冠状动脉血管病变的因素包括年龄、性别、血脂、血糖水平等,结果显示FFR0.8组患者血浆纤维蛋白原水平明显高于FFR≥0.8组(3.50±0.72 g/L比2.68±0.63 g/L,P0.05),纤维蛋白原水平与FFR值呈负相关(r=-0.477,P0.01);ROC曲线分析显示,最适宜的截断点为2.692 g/L,应用FFR值=0.8作为判断冠状动脉临界病变有无缺血的敏感度为92.9%,特异度为65.2%。结论血浆纤维蛋白原可用于检测冠状动脉临界病变心肌有无缺血,与冠状动脉临界病变心肌缺血程度相关,可作为预测冠状动脉临界病变心肌有无功能性缺血及支架植入的影响因素。     

El cociente de flujo cuantitativo en pacientes con estenosis aórtica grave y lesiones coronarias intermedias

Introduction and objectivesQuantitative flow ratio (QFR) is a novel noninvasive method for evaluating coronary physiology. However, data on the QFR in patients with aortic stenosis (AS) and coronary artery disease are scarce. Thus, we compared the diagnostic performance of the QFR with that of the resting distal to aortic coronary pressure (Pd/Pa) ratio, fractional flow reserve (FFR), and instantaneous wave-free ratio (iFR), as well as angiographic indices.MethodsA total of 221 AS patients with 416 vessels undergoing FFR/iFR measurements were enrolled in the study.ResultsThe mean percent diameter stenosis (%DS) was 58.6% ± 13.4% and the mean Pd/Pa ratio, FFR, iFR, and QFR were 0.95 ± 0.03, 0.85 ± 0.07, 0.90 ± 0.04, and 0.84 ± 0.07, respectively. A FFR ≤ 0.80 was noted in 26.0% of interrogated vessels, as well as an iFR ≤ 0.89 in 33.2% and QFR ≤ 0.80 in 31.7%. The QFR had better agreement with FFR (intraclass correlation coefficient [ICC], 0.96; 95% confidence interval [95%CI], 0.95-0.96) than with the iFR (ICC, 0.79; 95%CI, 0.75-0.82) and Pd/Pa ratio (ICC, 0.52; 95%CI, 0.44-0.58). In addition, the QFR showed better diagnostic accuracy (98.6% vs 94.2%; P < .001) and discriminant function (area under the curve = 0.996 vs 0.988; P < .001) when the iFR was used as the reference instead of FFR.ConclusionsIn patients with AS, the QFR has good agreement with both FFR and iFR. However, the agreement appears to be even better when the iFR is used as the reference, presumably due to the complex nature of the coronary physiology in the assessment of coronary artery disease in patients with severe AS.     

定量血流分数评价左心室舒张功能不全患者心肌缺血的价值

目的 探讨定量血流分数(quantitative flow ratio,QFR)在诊断左心室舒张功能不全患者心肌缺血的价值.方法 纳入2017年1月至2018年12月间广东省人民医院心脏超声诊断为左心室舒张功能不全但收缩功能正常,同时行冠状动脉造影及血流储备分数(fractional flow reserve,FFR)...     

Comparison of quantitative flow ratio with instantaneous wave-free ratio and resting full-cycle ratio during daily routine in the catheterization laboratory

Background

Quantitative flow ratio (QFR) is a novel, software-based method to evaluate the physiology of coronary lesions. The aim of this study was to compare QFR with the established invasive measurements of coronary blood flow using instantaneous wave-free ratio (iFR) or resting full-cycle ratio (RFR) in daily cathlab routine.

Methods

102 patients with stable coronary artery disease and a coronary stenosis of 40%−90% were simultaneously assessed with QFR and iFR or RFR. QFR-computation was performed by two certified experts using the appropriate software (QAngio XA 3D 3.2).

Results

QFR showed a significant correlation (r = 0.75, p < 0.001) to iFR and RFR. The area under the receiver curve for all measurements was 0.93 (95% confidence interval, 0.87–0.98) for QFR compared to iFR or RFR. QFR based assessment required less time with a median of 501 s (IQR 421–659 s) compared to iFR or RFR which required a median of 734 s to obtain the result (IQR 512–967 s; p < 0.001). The median use of contrast medium was similar with 21 mL (IQR 16–30 mL) for the QFR-based and 22 mL (IQR 15–35 mL) for the iFR- or RFR-based diagnostic. QFR diagnostic required less radiation. The median dose area product for QFR was 307cGycm² (IQR 151–429 cGycm²) compared to 599 cGycm² (IQR 345–1082 cGycm²) for iFR or RFR, p < 0.001.

Conclusion

QFR measurements of coronary artery blood flow correlate with iFR or RFR measurements and are associated with shorter procedure times and reduced radiation dose.     

Discordance between fractional flow reserve and instantaneous wave-free ratio in patients with severe aortic stenosis: A retrospective cohort study

BackgroundDiscordance between fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) occurs in approximately 20 % of cases. However, no studies have reported the discordance in patients with severe aortic stenosis (AS). We aimed to evaluate the diagnostic discordance between FFR and iFR in patients with severe AS.MethodsWe examined 140 consecutive patients with severe AS (164 intermediate coronary artery stenosis vessels). FFR and iFR were calculated in four quadrants based on threshold FFR and iFR values of ≤0.8 and ≤0.89, respectively (Group 1: iFR >0.89, FFR >0.80; Group 2: iFR ≤0.89, FFR >0.80; Group 3: iFR >0.89, FFR ≤0.80; and Group 4: iFR ≤0.89, FFR ≤0.80). Concordant groups were Groups 1 and 4, and discordant groups were Groups 2 and 3. Positive and negative discordant groups were Groups 3 and 2, respectively.ResultsThe median (Q1, Q3) FFR and iFR were 0.84 (0.76, 0.88) and 0.85 (0.76, 0.91), respectively. Discordance was observed in 48 vessels (29.3 %). In the discordant group, negative discordance (Group 2: iFR ≤0.89 and FFR >0.80) was predominant (45 cases, 93.6 %). Multivariate analysis showed that the left anterior descending artery [odds ratio (OR), 3.88; 95 % confidence interval (CI): 1.54–9.79, p = 0.004] and peak velocity ≥5.0 m/s (OR, 3.21; 95%CI: 1.36–7.57, p = 0.008) were independently associated with negative discordance (FFR >0.8 and iFR ≤0.89).ConclusionsIn patients with severe AS, discordance between FFR and iFR was predominantly negative and observed in 29.3 % of vessels. The left anterior descending artery and peak velocity ≥5.0 m/s were independently associated with negative discordance.     

QFR Versus FFR Derived From Computed Tomography for Functional Assessment of Coronary Artery Stenosis

ObjectivesThe aim of this study was to compare diagnostic performance between quantitative flow ratio (QFR) derived from coronary angiography and fractional flow reserve derived from computed tomography (FFR_CT) using fractional flow reserve (FFR) as the reference standard.BackgroundQFR and FFR_CT are recently developed, less invasive techniques for functional assessment of coronary artery disease.MethodsQFR, FFR_CT, and FFR were measured in 152 patients (233 vessels) with stable coronary artery disease.ResultsQFR was highly correlated with FFR (r = 0.78; p < 0.001), whereas FFR_CT was moderately correlated with FFR (r = 0.63; p < 0.001). Both QFR and FFR_CT showed moderately good agreement with FFR, presenting small values of mean difference but large values of root mean squared deviation (FFR-QFR, 0.02 ± 0.09; FFR-FFR_CT, 0.03 ± 0.11). The sensitivity, specificity, positive predictive value, and negative predictive value of QFR ≤0.80 for predicting FFR ≤0.80 were 90%, 82%, 81%, and 90%, respectively. Those of FFR_CT ≤0.80 for predicting FFR ≤0.80 were 82%, 70%, 70%, and 82%, respectively. The diagnostic accuracy of QFR ≤0.80 for predicting FFR ≤0.80 was 85% (95% confidence interval [CI]: 81% to 89%), whereas that of FFR_CT ≤0.80 for predicting FFR ≤0.80 was 76% (95% CI: 70% to 80%).ConclusionsQFR and FFR_CT showed significant correlation with FFR. Mismatches between QFR and FFR and between FFR_CT and FFR were frequent.     

Diagnostic performance and limitation of quantitative flow ratio for functional assessment of intermediate coronary stenosis

BackgroundThis study aimed to simultaneously investigate diagnostic performance and limitation of quantitative flow reserve (QFR) for assessing functionally significant coronary stenosis, focusing on factors affecting diagnostic accuracy of QFR.MethodsThis study evaluated 1) QFR diagnostic accuracy compared with fractional flow reserve (FFR) in patients with stable coronary artery disease (Cohort-A, n = 95) and 2) QFR reproducibility for non-culprit lesions (NCLs) assessment between acute and staged (14±5 days later) procedures in patients with ST-segment elevation myocardial infarction (STEMI) (Cohort-B, n = 65). All coronary angiography image acquisition was performed before the introduction of QFR system into our institution.ResultsCohort-A showed good correlation (r = 0.80, p<0.0001) between QFR and FFR; diagnostic accuracy of QFR for FFR ≤0.80 was 85.2% (sensitivity 80.4%, specificity 91.0%, positive predictive value 91.1%, negative predictive value 80.0%). There were 14 lesions showing discordance between QFR and FFR, which was primarily attributable to inadequate lesion visualization due to vessel overlap/tortuosity and/or insufficient intra-coronary contrast-media injection. In Cohort-B, there was also excellent correlation between acute and staged QFR; classification agreement of acute and staged QFR was 92.3%. Five lesions showed discordance between acute and staged QFR, 4 were due to limited image acquisition and/or high coronary flow velocity at acute phase of STEMI and 1 was borderline ischemia.ConclusionsQFR-derived physiological assessment of intermediate coronary stenosis is feasible, even in the acute setting of STEMI. Adjusting some technical factors may further improve the diagnostic performance of QFR.     

Physiologic Characteristics and Clinical Outcomes of Patients With Discordance Between FFR and iFR

ObjectivesThis study evaluated the physiologic characteristics of discordant lesions between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) and the prognosis at 5 years.BackgroundFFR or iFR have been standard methods for assessing the functional significance of coronary artery stenosis. However, limited data exist about the physiologic characteristics of discordant lesions and the prognostic implications resulting from these lesions.MethodsA total of 840 vessels from 596 patients were classified according to iFR and FFR; high iFR–high FFR (n = 580), low iFR–high FFR (n = 40), high iFR–low FFR (n = 69), and low iFR–low FFR (n = 128) groups, which were compared with a control group (n = 23). The differences in coronary circulatory indices including the coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and resistance reserve ratio (RRR) (resting distal arterial pressure × mean transit time / hyperemic distal arterial pressure × hyperemic mean transit time), which reflect the vasodilatory capacity of coronary microcirculation, were compared. Patient-oriented composite outcomes (POCO) at 5 years including all-cause death, any myocardial infarction, and any revascularization were compared among patients with deferred lesions.ResultsIn the low iFR–high FFR group, CFR, RRR, and IMR measurements were similar to the low iFR–low FFR group: CFR 2.71 versus 2.43 (p = 0.144), RRR 3.36 versus 3.68 (p = 0.241), and IMR 18.51 versus 17.38 (p = 0.476). In the high iFR–low FFR group, the CFR, RRR, and IMR measurements were similar to the control group: CFR 2.95 versus 3.29 (p = 0.160), RRR 4.28 versus 4.00 (p = 0.414), and IMR 17.44 versus 17.06 (p = 0.818). Among the 4 groups, classified by iFR and FFR, CFR and RRR were all significantly different, except for IMR. However, there were no significant differences in the rates of POCO, regardless of discordance between the iFR and FFR. Only the low iFR–low FFR group had a higher POCO rate compared with the high iFR–high FFR group (adjusted hazard ratio: 2.46; 95% confidence interval: 1.17 to 5.16; p = 0.018).ConclusionsDifferences in coronary circulatory function were found, especially in the vasodilatory capacity between the low iFR–high FFR and high iFR–low FFR groups. FFR–iFR discordance was not related to an increased risk of POCO among patients with deferred lesions at 5 years. (Clinical, Physiological and Prognostic Implication of Microvascular Status; NCT02186093; Physiologic Assessment of Microvascular Function in Heart Transplant Patients; NCT02798731)     

Diagnostic accuracy of instantaneous wave free‐ratio in clinical practice

Aims

To evaluate the correlation between iFR and FFR in real‐world clinical practice.

Methods and Results

Retrospective, single‐centre study of 229 consecutive pressure‐wire studies (n_p = 158). Real‐time iFR and FFR measurements were performed for angiographically borderline stenoses. Functionally significant stenoses were defined as iFR <0.86 or FFR ≤0.80. An iFR between 0.86 and 0.93 was considered within the grey zone (Hybrid approach). Median iFR and FFR (IQR) were 0.92 (0.87‐0.95) and 0.83 (0.76‐0.89), respectively. Pearson's correlation coefficient was 0.75 (P < 0.001). Bland‐Altman plot showed a mean difference between iFR and FFR that remained consistent throughout the range of values. The optimal iFR cutoff was 0.91—sensitivity 80%, specificity 82% with ROC area under curve of 89%. Using the Hybrid iFR‐FFR strategy, we demonstrated high accuracy of iFR results—sensitivity 95%, specificity 96%, PPV 95%, and NPV 96%. In addition, this method would have avoided adenosine in 56% of patients. Mean follow‐up period was 17.2 (±3.4) months. All‐cause mortality was 3.2% (n_p = 5) and repeat intervention was required in six lesions (2.6%).

Conclusions

This study demonstrates that iFR is a valuable adjunct to FFR using the Hybrid iFR‐FFR strategy in a real‐world population. The use of adenosine may be avoided in about half the cases.

     

Comparison of Quantitative Flow Ratio and Invasive Physiology Indices in a Diverse Population at a Tertiary United States Hospital

BackgroundQuantitative flow ratio (QFR) is a technology to evaluate the coronary stenosis significance on 3-dimensional quantitative coronary angiography. The aim of this study is to evaluate and compare the QFR versus fractional flow reserve (FFR) and/or instantaneous free-wave ratio (iFR) in a US population with a fair African American population representation.Methods and resultsThis was a retrospective, observational and single-center study that enrolled 100 patients who underwent coronary angiography. The diagnostic performance of QFR in terms of sensitivity was 0.80 (95%CI 0.64–0.97) and specificity was 0.95 (95% CI 0.90–1.00), the positive predictive value (PPV) was 0.83 (0.68–0.98), while the negative predictive value (NPV) was 0.94 (0.88–0.99). The overall accuracy was 0.91 and area under the curve (AUC) was 0.92 (95% CI 0.87–0.97).The R-squared was 0.54 and the Bland-Altman plot showed a bias of 0.0016 (SD 0.063) and limits of agreement (LOA): Upper LOA 0.13 and Lower LOA −0.12. In African Americans (n = 33), accuracy, AUC, sensitivity, specificity (94%; 0.90 [0.80–1.00]; 0.90 [0.71–1.00]; 0.96 [0.87–1.00], respectively) were better than those for the overall population.ConclusionsIn a US-based representative population, vessel QFR accuracy and agreement with FFR as reference is high. Diagnostic performance of QFR in African Americans is also excellent.