Relationship between Whole Blood Viscosity and Lesion Severity in Coronary Artery Disease

Objective  This article investigates the relationship of fractional flow reserve (FFR) with whole blood viscosity (WBV) in patients who were diagnosed with chronic coronary syndrome and significant stenosis in the major coronary arteries and underwent the measurement of FFR. Material and Method  In the FFR measurements performed to evaluate the severity of coronary artery stenosis, 160 patients were included in the study and divided into two groups as follows: 80 with significant stenosis and 80 with nonsignificant stenosis. WBVs at low shear rate (LSR) and high shear rate (HSR) were compared between the patients in the significant and nonsignificant coronary artery stenosis groups. Results  In the group with FFR < 0.80 and significant coronary artery stenosis, WBV was significantly higher compared with the group with nonsignificant coronary artery stenosis in terms of both HSR (19.33 ± 0.84) and LSR (81.19 ± 14.20) ( p  < 0.001). In the multivariate logistic regression analysis, HSR and LSR were independent predictors of significant coronary artery stenosis (HSR: odds ratio: 1.67, 95% confidence interval: 1.17–2.64; LSR: odds ratio: 2.46, 95% confidence interval: 2.19–2.78). In the receiver operating characteristic (ROC) curve analysis, when the cutoff value of WBV at LSR was taken as 79.23, it had 58.42% sensitivity and 62.13% specificity for the prediction of significant coronary artery stenosis (area under the ROC curve: 0.628, p  < 0.001). Conclusion  WBV, an inexpensive biomarker that can be easily calculated prior to coronary angiography, was higher in patients with functionally severe coronary artery stenosis, and thus could be a useful marker in predicting the hemodynamic severity of coronary artery stenosis in patients with chronic coronary syndrome.     

Factors influencing the functional significance in intermediate coronary stenosis

Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve (FFR) in interme-diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 intermediate coronary lesions. Pressure-derived FFR of these lesions was gained at maximal hyperemia induced by intravenous adenosine infusion. An FFR < 0.80 was considered as abnormal functional significance. Anatomic parameters at the lesion sites were obtained by off-line quantitative coronary angiography analysis (QCA). The predictive value of the demographic characteristics and anatomic parameters for FFR in these intermediate lesions was assessed using multiple linear and binary logistic regression analysis. Results Overall, FFR < 0.8 was found in 70 (34%) of the total 203 intermediate coronary lesions. FFR values were positively correlated with QCA-measured minimum lumen diameters (MLD, r = 0.372, P = 0.000) and the reference vessel diameters (RVD, r = 0.217, P = 0.002) were negatively correlated with percent area stenosis (AS, r = -0.251, P = 0.000) and percent diameter stenosis (DS, r = -0.210, P = 0.000). Age, MLD and the lesion location in different coronary arteries were the independent determinants of FFR < 0.8. Conclusions MLD can predict the functional significance of intermediate coro-nary stenosis, while age and the lesion location in different coronary arteries should be taken into account as important influencing factors of FFR values.     

Usefulness of noninvasive fractional flow reserve computed from coronary computed tomographic angiograms for intermediate stenoses confirmed by quantitative coronary angiography

Coronary lesions of intermediate severity often cause ischemia, and fractional flow reserve (FFR)-guided revascularization for these coronary lesions is safe and effective. FFR derived from coronary computed tomography (FFR(CT)) is a noninvasive method for diagnosis of lesion-specific ischemia, but its performance for intermediate stenoses has not been examined to date. We examined the performance of FFR(CT) versus FFR at the time of invasive angiography in 66 vessels of 60 patients who were identified as having an intermediate stenosis, defined by quantitative coronary angiographic percent diameter stenosis 40% to 69%. Ischemia for FFR(CT) and FFR was defined as ≤0.80. Diagnostic performance of FFR(CT) was determined compared to an invasive FFR standard. Mean age of the study group was 63.5 ± 8.1 years (81% men). Thirty-one patients (47%) demonstrated ischemia with an FFR ≤0.80, with 2 of 16 (12.5%), 21 of 37 (56.8%), and 8 of 13 (61.5%) lesions of 40% to 49%, 50% to 59%, and 60% to 69% stenosis causal of ischemia, respectively. At an FFR ≤0.80 cutoff for lesion-specific ischemia, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFR(CT) were 86.4%, 90.3%, 82.9%, 82.4%, and 90.6%, respectively, with an area under the receiver operator characteristics curve of 0.95 (p <0.001) and good correlation to FFR (0.60, p <0.0001). No biases between FFR(CT) and FFR were noted by Bland-Altman analysis (0.03 ± 0.12, p = 0.054). In conclusion, FFR(CT) is a novel noninvasive method for diagnosis of lesion-specific ischemia of coronary lesions of intermediate stenosis severity.     

Diagnostic Value of Transluminal Attenuation Gradient for the Presence of Ischemia as Defined by Fractional Flow Reserve and Quantitative Positron Emission Tomography

Objectives

The aim of this study was to investigate the incremental diagnostic value of transluminal attenuation gradient (TAG), TAG with corrected contrast opacification (TAG-CCO), and transluminal diameter gradient (TDG) over coronary computed tomography angiography (CTA)–derived diameter stenosis alone for the identification of ischemia as defined by both the invasive reference standard fractional flow reserve (FFR) and the noninvasive reference standard quantitative positron emission tomography (PET).

Ten‐year clinical outcomes in patients with intermediate coronary stenosis according to the combined culprit lesion

BackgroundWe assessed the long‐term clinical outcomes of an intermediate lesion (IL) according to the presence of a combined culprit lesion (CCL).HypothesisLong‐term clinical outcomes of IL may be affected by the presence of a CCL.MethodsAngiographic findings (n = 1096) and medical chart were reviewed. Patients with IL were divided into two groups: IL without CCL group (n = 383, 64.5%) and IL with CCL group (n = 211, 35.5%).ResultsThe major adverse cardiovascular events (MACE) in the IL with CCL group were significantly higher than those in the IL without CCL group (death: 12.3% vs. 7.0%, myocardial infarction: 3.3%vs. 0.5%, stroke: 6.6% vs. 2.6%, and revascularization [RVSC]: 25.1% vs. 7.6%) during a mean follow up period of 118.4 ± 5.5 months. IL related RVSC rate in the IL with CCL group was higher than that in the IL without CCL group (5.7% vs. 2.1%, p = 0.020). RVSC rate related to IL in total subjects was lower than that related to stented lesion (3.4% vs. 6.4%). The important predictors of total MACE in total subjects were the presence of CCL, IL percent diameter stenosis, hypertension, history of percutaneous coronary intervention, blood glucose and ejection fraction. The predictors of IL related RVSC were IL percent diameter stenosis and IL located in the right coronary artery.Conclusion10‐year clinical outcomes of an IL (especially IL without CCL) were better than those of stented lesions. This study suggests that the IL can be safely followed up in sites that do not have ability to assess functional study.     

北京社区自然人群冠状动脉钙化的多排螺旋CT初步研究

目的利用64排螺旋CT(64multi-detector computed tomography,64-MDCT)初步评价北京社区人群的冠状动脉钙化(coronary artery calcium,CAC)情况。方法对北京地区社区人群进行抽样研究,利用64-MDCT(GE,LightSpeed VCT)对1480例研究对象进行冠状动脉钙化扫描,应用Agatston积分法分别计算其冠状动脉钙化积分(coronary artery calcium score,CACS),观察CAC分布特征,以性别及年龄分组比较组间的CAC差别。结果总样本CAC阳性率为29.9%;男性组的CAC阳性率为37.6%,明显高于女性组的23.1%(P0.01)。同一性别各年龄组的CACS均呈正偏态分布,CAC阳性率和CACS均随年龄增加而显著增高(P0.01);40～、50～岁组的CAC阳性率以及40～、50～、60～岁组的CACS存在性别间的显著性差异。1480例研究对象有206例(13.9%)为单支钙化,237例(16.0%)为多支钙化;总样本共5920支冠状动脉中以前降支(26.8%)及右冠状动脉(13.5%)钙化阳性率为高(P0.01)。结论 64-MDCT能够方便、快速地量化检测社区人群的CAC的发病情况,评价人群中的CAC分布特征及规律,从而初步判定人群中的冠状动脉粥样硬化病变的流行病学特征。     

定量冠状动脉造影参数与心肌血流储备分数的相关性分析

目的 探讨定量冠状动脉造影（QCA）参数与心肌血流储备分数（FFR）的相关性.方法 共纳入231例患者325处临界病变,根据FFR值分为两组,FFR＞0.80组（n=177）及FFR≤0.80组（n=148）.结果 两组患者冠状动脉直径狭窄[（58.7±13.4）％比（68.2±11.6）％,P＜0.001]、面积狭窄[（80.9±11.7）％比（88.4±8.0）％,P＜0.001]差异有统计学意义,上述指标与FFR值呈负相关（相关系数分别为r=-0.352,P＜0.001,r=-0.347,P＜0.001）.最小管腔直径两组差异有统计学意义[（1.18 ±0.46）mm比（0.83 ±0.39）mm,P＜0.001],与FFR值呈正相关（r=0.374,P＜0.001）.ROC曲线分析提示,冠状动脉最小管腔直径ROC曲线下面积为0.721,最小管腔面积≥1.05 mm时,预测病变无功能学意义（FFR ＞0.80）的敏感度为62.7％,特异度为73.6％.结论 QCA中冠状动脉直径狭窄百分比、面积狭窄百分比、最小管腔直径与FFR值存在相关性,但预测病变是否为心肌缺血相关靶病变的敏感度和特异度不高,仍应尽量推广功能性心肌缺血指标FFR的使用.     

Computed Tomography-Derived Fractional Flow Reserve in the Detection of Lesion-Specific Ischemia: An Integrated Analysis of 3 Pivotal Trials

Invasive fractional flow reserve (FFR) is the gold standard for the determination of physiologic stenosis severity and the need for revascularization. FFR computed from standard acquired coronary computed tomographic angiography datasets (FFR_CT) is an emerging technology which allows calculation of FFR using resting image data from coronary computed tomographic angiography (CCTA). However, the diagnostic accuracy of FFR_CT in the evaluation of lesion-specific myocardial ischemia remains to be confirmed, especially in patients with intermediate coronary stenosis. We performed an integrated analysis of data from 3 prospective, international, and multicenter trials, which assessed the diagnostic performance of FFR_CT using invasive FFR as a reference standard. Three studies evaluating 609 patients and 1050 vessels were included. The total calculated sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FFR_CT were 82.8%, 77.7%, 60.8%, 91.6%, and 79.2%, respectively, for the per-vessel analysis, and 89.4%, 70.5%, 69.7%, 89.7%, and 78.7%, respectively, for the per-patient analysis. Compared with CCTA alone, FFR_CT demonstrated significantly improved accuracy (P < 0.001) in detecting lesion-specific ischemia. In patients with intermediate coronary stenosis, FFR_CT remained both highly sensitive and specific with respect to the diagnosis of ischemia. In conclusion, FFR_CT appears to be a reliable noninvasive alternative to invasive FFR, as it demonstrates high accuracy in the determination of anatomy and lesion-specific ischemia, which justifies the performance of additional randomized controlled trials to evaluate both the clinical benefits and the cost-effectiveness of FFR_CT-guided coronary revascularization.     

Coronary calcification is associated with elevated serum lipoprotein (a) levels in asymptomatic men over the age of 45 years: A cross-sectional study of the Korean national health checkup data

Lipoprotein a (Lp (a)) and coronary artery calcification (CAC) are markers of coronary artery and cardiovascular diseases. However, the association between Lp (a) and CAC in asymptomatic individuals remains unclear. In this study, we aimed to determine the influence of Lp (a) on CAC in asymptomatic individuals.We included 2019 asymptomatic Korean adults who underwent testing for a coronary artery calcium score (CACS) and Lp (a) at the Gangnam Severance Hospital Health Checkup Center in Korea from January 2017 to August 2019. Participants were divided into 2 groups: CACS = 0 and CACS > 0. Factors affecting the CACS were analyzed by sex. Because age is a major risk factor for atherosclerosis, ≥45 years in men and ≥55 years in women, we further divided participants into 4 subgroups (≥45 and <45 in men, ≥55 and <55 in women). Factors affecting the CACS in the 4 groups were analyzed.There was a positive correlation between the CACS and traditional cardiovascular risk factors. Lp (a) positively correlated with the CACS in men (P < .01) and remained significant after multivariable logistic regression (P < .01). The same result was observed in men aged ≥45 years (P < .01).Lp (a) is an independently associated factor of CAC and a marker of coronary atherosclerosis in asymptomatic men aged ≥45 years. In asymptomatic men aged ≥45 years, Lp (a) should be measured, and intensive Lp (a)-lowering treatment should be considered.     

Intravascular ultrasound criteria for the assessment of the functional significance of intermediate coronary artery stenoses and comparison with fractional flow reserve

The functional significance of coronary artery stenoses of intermediate severity is important in determining strategy in patient care. Intravascular ultrasound (IVUS) is often used to evaluate coronary stenosis severity. However, at present, few data are available about the role IVUS in the assessment of functional significance of intermediate lesions. Myocardial fractional flow reserve (FFR) <0.75 is a reliable index of a functionally severe coronary stenosis. In 53 lesions we assessed (1) by pressure wire: FFR (index of functional significance), and (2) by IVUS: minimal lumen cross-sectional area (MLA, square millimeters), minimal lumen diameter (MLD, millimeters), lesion length (millimeters), and percent area stenosis at the lesion site. By regression analysis, percent area stenosis and lesion length had a significant inverse correlation with FFR (r = -0.58, p <0.001, r = -0.41, p <0.004, respectively). MLD and MLA showed a significant positive relation with FFR (r = 0.51, p <0.001, r = 0.41, p <0.004, respectively). By using a receiver operating characteristic (ROC) curve, we identified a percent area stenosis > 70% (sensitivity 100%, specificity 68%), a MLD < or = 1.8 mm (sensitivity 100%, specificity 66%), a MLA < or =4.0 mm2 (sensitivity 92%, specificity 56%), and a lesion length of >10 mm (sensitivity 41%, specificity 80%) to be the best cut-off values to fit with a FFR <0.75. The combined evaluation of both percent area stenosis and MLD made the IVUS examination more specific (sensitivity 100%, specificity 76%). In 53 intermediate coronary lesions found by angiography, IVUS area stenosis >70%, MLD < or =1.8 mm, MLA < or =4.0 mm2, and lesion length > 10 mm reliably identified functionally critical intermediate coronary stenoses.     

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。     

Value of fractional flow reserve in making decisions about bypass surgery for equivocal left main coronary artery disease

OBJECTIVE—To investigate the value of coronary pressure derived fractional flow reserve (FFR) measurements in supporting decisions about medical or surgical treatment in patients with angiographically equivocal left main coronary artery stenosis.
DESIGN—A two centre prospective single cohort follow up study.
INTERVENTIONS—FFR of the left main coronary artery was determined in 54 consecutive patients with angiographically equivocal left main coronary artery disease. If FFR was 0.75, medical treatment was chosen; if FFR was < 0.75, surgical treatment was chosen.
MAIN OUTCOME MEASURES—Freedom from death, myocardial infarction, or any coronary revascularisation procedure.
RESULTS—In 24 patients (44%), FFR was 0.75 and medical treatment was chosen (medical group). In the remaining 30 patients (56%), FFR was < 0.75 and bypass surgery was performed (surgical group). Mean (SD) follow up was 29 (15) months (range 12-65 months). Survival among patients at three years of follow up was 100% in the medical group and 97% in the surgical group. Event-free survival was 76% in the medical group and 83% in the surgical group.
CONCLUSIONS—FFR supports decision making in equivocal left main coronary artery disease. If FFR is below 0.75, the decision for bypass surgery is supported. If FFR is above 0.75, a conservative approach is justified.


Keywords: coronary artery disease; left main coronary artery; fractional flow reserve; coronary artery bypass     

CT Angiographic and Plaque Predictors of Functionally Significant Coronary Disease and Outcome Using Machine Learning

ObjectivesThe goal of this study was to investigate the association of stenosis and plaque features with myocardial ischemia and their prognostic implications.BackgroundVarious anatomic, functional, and morphological attributes of coronary artery disease (CAD) have been independently explored to define ischemia and prognosis.MethodsA total of 1,013 vessels with fractional flow reserve (FFR) measurement and available coronary computed tomography angiography were analyzed. Stenosis and plaque features of the target lesion and vessel were evaluated by an independent core laboratory. Relevant features associated with low FFR (≤0.80) were identified by using machine learning, and their predictability of 5-year risk of vessel-oriented composite outcome, including cardiac death, target vessel myocardial infarction, or target vessel revascularization, were evaluated.ResultsThe mean percent diameter stenosis and invasive FFR were 48.5 ± 17.4% and 0.81 ± 0.14, respectively. Machine learning interrogation identified 6 clusters for low FFR, and the most relevant feature from each cluster was minimum lumen area, percent atheroma volume, fibrofatty and necrotic core volume, plaque volume, proximal left anterior descending coronary artery lesion, and remodeling index (in order of importance). These 6 features showed predictability for low FFR (area under the receiver-operating characteristic curve: 0.797). The risk of 5-year vessel-oriented composite outcome increased with every increment of the number of 6 relevant features, and it had incremental prognostic value over percent diameter stenosis and FFR (area under the receiver-operating characteristic curve: 0.706 vs. 0.611; p = 0.031).ConclusionsSix functionally relevant features, including minimum lumen area, percent atheroma volume, fibrofatty and necrotic core volume, plaque volume, proximal left anterior descending coronary artery lesion, and remodeling index, help define the presence of myocardial ischemia and provide better prognostication in patients with CAD. (CCTA-FFR Registry for Risk Prediction; NCT04037163)     

Presence of Anomalous Coronary Seen on Angiogram Is Not Associated with Increased Risk of Significant Coronary Artery Disease

It is unclear if anomalous coronary arteries are at higher risk for atherosclerosis. The link between anomalous coronary artery and early coronary artery disease has been suggested. The aim of this study is to determine whether the coronary artery anomaly predisposes to development of significant coronary disease. Using retrospective chart review, patients with documented anomalous coronary arteries recognized during coronary angiography between years 2000 to 2007 were analyzed. Prevalence of significant atherosclerotic coronary artery disease (defined as more than 50% luminal narrowing) was compared between normal and anomalous coronaries. A total of 147 patients with anomalous coronary arteries were found. Right coronary artery was the most common anomalous artery 128 of 148 (86.5%) in our dataset. There was no difference in the occurrence of atherosclerosis between anomalous and nonanomalous coronaries. Significant atherosclerosis was present in 59 of the 148 anomalous coronary arteries (37.8%), and 112 of the 293 nonanomalous coronary arteries (38.2%, p = 0.9). On the basis of our study, there is no evidence that anomalous coronary arteries predispose to significant coronary artery disease in comparison to normal coronary arteries.     

Distribution of coronary atherosclerosis in patients with coronary artery disease

The distribution of coronary atherosclerosis has not been fully clarified. We measured coronary artery calcium score (CACS) in 624 consecutive patients for the right coronary artery (RCA), left main trunk (LMT), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCx), then calculated total CACS. Coronary artery calcium score was measured using the Agatston method. We divided these patients into four groups: CACS 1–100 (Group A, n = 267), CACS 101–400 (Group B, n = 160), CACS 401–1000 (Group C, n = 110), and CACS >1000 (Group D, n = 87). In Group A, B, and C, the CACS in LAD was significantly higher than in the other three arteries (P < 0.0001). In Group D, the CACS was not significantly different between LAD and RCA (P = 0.6930). In Groups A, B, and C, coronary artery calcium (CAC) was more frequently found in LAD compared with other arteries (P < 0.0001). However, in Group D the prevalence of CAC was not significantly different among the three arteries (P = 0.4435). Coronary artery calcium was found more frequently in LAD than in the other coronary arteries in patients with mild to high CAC, but not in those with very high CAC.     

Clinical Application of Fractional Flow Reserve–Guided Percutaneous Coronary Intervention for Stable Coronary Artery Disease

Revascularization in stable ischemic heart disease (SIHD) is indicated in patients on optimal medical therapy with angina and/or demonstrable ischemia and a significant stenosis in one or more epicardial coronary arteries. Angiography alone, however, cannot accurately determine the hemodynamic significance of coronary lesions, particularly those of intermediate stenosis severity. A lesion may appear significant on coronary angiogram but may not have functional significance. Percutaneous coronary intervention (PCI) of functionally insignificant coronary artery lesions may have serious consequences; therefore, judicious decision-making in the cardiac catheterization laboratory is indicated. For this reason, it is becoming increasingly important to show that a stenosis is capable to induce myocardial ischemia prior to intervention. Fractional flow reserve (FFR) has emerged as a useful tool for this purpose. In this review, we will briefly discuss the principle of FFR, current evidence and rationale supporting its use, and comparison with other modalities.     

Functional assessment of sequential coronary artery fistula and coronary artery stenosis with fractional flow reserve and stress adenosine myocardial perfusion imaging

Coronary artery fistula is an abnormal connection between one coronary artery to another coronary artery or cardiac chambers. The coronary artery fistula may cause significant shunting of blood and cause “pseudo-stenosis” or “steal phenomenon”. This will also accentuate pre-existing mild-moderate de novo coronary lesions with resultant greater pressure gradient difference across the lesions. Thus, fractional flow reserve can be a useful tool to guide intervention decision on the coronary artery fistula. There are very few published reports regarding the use of FFR to assess coronary artery fistula. In fact, there is no outcome data regarding the deferment of coronary artery fistula intervention when the FFR is not physiologically significant. This case highlighted the use of FFR to evaluate the functional significance of coronary fistula in the setting of ischemia evaluation and it was proven to be safe to defer intervention with good 3 year clinical outcome. Stress adenosine myocardial perfusion imaging correlated with the FFR result.     

Effect of nonobstructive coronary stenosis on coronary microvascular dysfunction and long‐term outcomes in patients with INOCA

BackgroundIschemic pain with no‐obstructive coronary artery (INOCA) is clinically significant and defined by nonobstructive coronary stenosis <50%. Coronary microvascular dysfunction (CMD) is a relevant cause associated with adverse outcomes.ObjectivesInvestigated the effect of no‐stenosis (0% stenosis) and non‐obstructive (0% < stenosis < 50%) on the prognostic impact of CMD in INOCA.MethodA retrospective study assessed the coronary microvascular function in 151 INOCA patients who underwent invasive angiography by the coronary angiography‐derived index of microcirculation‐resistance (caIMR). CZT‐SPECT was performed to evaluate myocardial perfusion imaging (MPI) abnormalities. Chi‐square test/Fisher exact test, Student t‐test, Kaplan–Meier curve, and Uni‐multivariable Cox proportional models were used for analysis. Clinical outcomes were major adverse cardiovascular events (MACE) during a median follow‐up of 35 months.ResultNo‐stenosis was present in 71 (47%) INOCA patients, and 80 (53%) were with nonobstructive. CMD (caIMR ≥ 25) was more prevalent in patients with no‐stenosis than nonobstructive (76.1% vs. 48.8%, p = .001), along with abnormal MPI (39.4% vs. 22.5%, p = .024). The MACE rates were not different between no‐stenosis and nonobstructive stenosis. CMD showed an increased risk of MACE for all INOCA. No‐stenosis with CMD had the worst prognosis. Cox regression analysis identified CMD and abnormal MPI as predictors of MACE in all INOCA and patients with no‐stenosis. However, no‐stenosis and nonobstructive stenosis were not predictors of MACE in INOCA.ConclusionCMD was more frequently present in INOCA with no‐stenosis. However, there was no difference in long‐term clinical outcomes between no‐stenosis and nonobstructive stenosis. CMD could independently predict poor outcomes in INOCA, particularly in patients with no‐stenosis.     

CT FFR for Ischemia-Specific CAD With a New Computational Fluid Dynamics Algorithm: A Chinese Multicenter Study

ObjectivesThe aim of this study was to validate the feasibility of a novel structural and computational fluid dynamics–based fractional flow reserve (FFR) algorithm for coronary computed tomography angiography (CTA), using alternative boundary conditions to detect lesion-specific ischemia.BackgroundA new model of computed tomographic (CT) FFR relying on boundary conditions derived from structural deformation of the coronary lumen and aorta with transluminal attenuation gradient and assumptions regarding microvascular resistance has been developed, but its accuracy has not yet been validated.MethodsA total of 338 consecutive patients with 422 vessels from 9 Chinese medical centers undergoing CTA and invasive FFR were retrospectively analyzed. CT FFR values were obtained on a novel on-site computational fluid dynamics–based CT FFR (uCT-FFR [version 1.5, United-Imaging Healthcare, Shanghai, China]). Performance characteristics of uCT-FFR and CTA in detecting lesion-specific ischemia in all lesions, intermediate lesions (luminal stenosis 30% to 70%), and “gray zone” lesions (FFR 0.75 to 0.80) were calculated with invasive FFR as the reference standard. The effect of coronary calcification on uCT-FFR measurements was also assessed.ResultsPer vessel sensitivities, specificities, and accuracies of 0.89, 0.91, and 0.91 with uCT-FFR, 0.92, 0.34, and 0.55 with CTA, and 0.94, 0.37, and 0.58 with invasive coronary angiography, respectively, were found. There was higher specificity, accuracy, and AUC for uCT-FFR compared with CTA and qualitative invasive coronary angiography in all lesions, including intermediate lesions (p < 0.001 for all). No significant difference in diagnostic accuracy was observed in the “gray zone” range versus the other 2 lesion groups (FFR ≤0.75 and >0.80; p = 0.397) and in patients with “gray zone” versus FFR ≤0.75 (p = 0.633) and versus FFR >0.80 (p = 0.364), respectively. No significant difference in the diagnostic performance of uCT-FFR was found between patients with calcium scores ≥400 and <400 (p = 0.393).ConclusionsThis novel computational fluid dynamics–based CT FFR approach demonstrates good performance in detecting lesion-specific ischemia. Additionally, it outperforms CTA and qualitative invasive coronary angiography, most notably in intermediate lesions, and may potentially have diagnostic power in gray zone and highly calcified lesions.     

Use of Coronary Physiology in the Catheterization Laboratory to Guide Treatment in Patients With Coronary Artery Disease

Fractional flow reserve (FFR) is an invasive pressure–derived index of epicardial stenosis severity used in the catheterization laboratory to assess the hemodynamic significance of coronary lesions when non-invasive functional assessment has either not been performed or is inconclusive. The rationale for the use of FFR is that coronary angiography cannot accurately predict the hemodynamic significance of lesions with diameter stenosis <90% and that there is a large body of literature supporting the use of FFR for directing coronary revascularization. Specifically, in patients with stable angina and low-risk acute coronary syndromes, revascularization with either percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery should be deferred for epicardial coronary stenoses with an FFR > 0.80. Use of FFR to direct coronary revascularization should continue to increase as it has been demonstrated to improve outcomes and reduce cost.