A pitfall of fractional flow reserve associated with the presence of collateral circulation

An 82-year-old man had a severe stenosis in the proximal left anterior descending artery (LAD) and an intermediate stenosis in the distal right coronary artery (RCA). The territory of mid to distal LAD was perfused via an angiographically well-developed collateral circulation from the distal RCA. Fractional flow reserve (FFR) in the distal RCA was 0.84. After successful coronary intervention for the proximal LAD, repeat FFR in the distal RCA was 0.96. In this case, the severity of the stenosis in the donor artery was overestimated by using FFR due to the presence of well-developed collateral circulation.     

The Impact of Downstream Coronary Stenosis on Fractional Flow Reserve Assessment of Intermediate Left Main Coronary Artery Disease: Human Validation

ObjectivesThe aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel.BackgroundAccurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel.MethodsAfter percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFR_true) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFR_app) measured in the presence of stenosis.ResultsIn 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFR_true of the LMCA was significantly lower than FFR_app (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFR_app was >0.85, FFR_true was >0.80.ConclusionsIn most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.     

Influence of Local Myocardial Damage on Index of Microcirculatory Resistance and Fractional Flow Reserve in Target and Nontarget Vascular Territories in a Porcine Microvascular Injury Model

Objectives

The aim of this study was to investigate the influence of microvascular damage in one vessel territory on invasively measured physiological parameters in the other vessel, using a porcine microvascular damage model.

Fractional flow reserve for the assessment of complex multivessel disease in a patient after hybrid coronary revascularization

We present a case of a 43‐year‐old woman with history of hybrid coronary revascularization [endoscopic atraumatic coronary artery bypass (ACAB)] of left internal mammary artery (LIMA) to the left anterior descending artery (LAD) and stent implantation in right coronary artery (RCA), who presented 6 years later with recurrent atypical angina. Coronary angiography revealed patent LIMA to LAD and RCA stent, with a new lesion in an obtuse marginal artery and significant progression of disease in the proximal/mid LAD proximal to LIMA touchdown. To further evaluate the hemodynamic significance of these new disease segments, the patient underwent fractional flow reserve (FFR) assessment of the left coronary system with subsequent stent implantation in the proximal/mid LAD. This case illustrates (1) the critical value of FFR assessment in determining the ischemia provoking lesions in this post ACAB patient with complex multivessel coronary artery disease; and (2) the accelerated progression of atherosclerosis in bypassed segments as compared to segments proximal to stents. © 2012 Wiley Periodicals, Inc.     

影响冠状动脉左前降支近段临界病变血流储备分数的相关因素分析

目的探讨可能对冠状动脉左前降支近段临界病变血流储备分数(FFR)产生影响的因素。方法纳入2017年9月至2020年1月首都医科大学附属北京安贞医院167例冠状动脉左前降支近段临界病变的患者,行左前降支FFR检查,根据FFR值分为FFR≥0.75组(105例)及FFR<0.75组(62例),比较两组患者相关临床指标的差异,探讨FFR值与病变狭窄程度之间的关系。进行logistic多因素回归分析与FFR值相关的因素。结果两组患者性别、年龄、吸烟史、合并高血压病、合并糖尿病、体重指数、左心室射血分数、最小管腔直径、直径狭窄率、空腹血糖、总胆固醇、高密度脂蛋白胆固醇以及糖化血红蛋白水平等比较,差异均无统计学意义(均P>0.05);FFR<0.75组病变长度[(20.17±7.42)mm比(16.98±6.01)mm,P=0.045]及分支血管积分[(3.36±1.38)分比(2.71±1.04)分,P=0.023]显著大于FFR≥0.75组,差异有统计学意义。Pearson相关分析显示,FFR值与直径狭窄率无相关关系(r=0.371,P=0.067)。logistic多因素回归分析显示,病变长度(OR 2.197,95%CI 1.608~3.372,P=0.017)、分支血管积分(OR 2.101,95%CI 1.079~3.035,P=0.020)与FFR<0.75相关。结论左前降支近段临界病变冠状动脉狭窄的病变长度及病变以远的分支血管积分可能对FFR值产生影响。     

Frequency of abnormal fractional flow reserve measurements among major coronary arteries

Background

Fractional flow reserve(FFR) is a validated tool for evaluating functional severity and guiding the revascularization of angiographically moderate coronary artery lesions.

Clinical Events After Deferral of LAD Revascularization Following Physiological Coronary Assessment

Background

Physicians are not always comfortable deferring treatment of a stenosis in the left anterior descending (LAD) artery because of the perception that there is a high risk of major adverse cardiac events (MACE). The authors describe, using the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) trial, MACE rates when LAD lesions are deferred, guided by physiological assessment using fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR).

定量冠状动脉造影和血管内超声预测左冠状动脉前降支单支病变致血流储备分数〈0．80的价值

目的本研究旨在针对左冠状动脉前降支（LAD）单支病变的不稳定型心绞痛（UA）患者,探讨定量冠状动脉造影（QCA）和血管内超声（IVUS）颅测冠状动脉血流储备分数（FFR）〈0．80的最佳临界值。方法连续人选169例LAD单支病变的患者,分别测定QCA、IVUS和FFR。使用受试者工作曲线（ROC）建立QCA和IVUS测定值预测FFR〈0．80的价值。结果99例患者（58．6％）FFR〈0．80。最小管腔面积（MLA）和斑块负荷（PB）是预测FFR〈0．80的两个独立因子。病变长度预测FFR〈0．80的价值较小。MLA和PB预测总体LAD病变的FFR〈0．80的临界值分别为3．03mm2和75．4％。MLA和PB对LAD近端（临界值分别为3．04mm2和76．5％）及远端（临界值分别为2．82mm2和80．6％）病变具有相似的诊断价值。联合MLA（2．82mm。）和PB（80．6％）对于诊断远端LAD具有更大的意义。结论当病变局限在LAD时,MLA和PB预测FFR〈0．80具有相似的诊断价值。联合MLA和PB对预测远端LAD病变的功能学意义具有更大的价值。     

Measurement of fractional flow reserve in patients with multi-vessel coronary artery disease and borderline lesions prevents unnecessary revascularisation procedures

BACKGROUND: Patients with multi-vessel coronary artery disease (CAD) are selected for percutaneous coronary interventions (PCI) or surgical revascularisation. The appropriateness of "ad hoc" PCI of borderline lesions (<70% of lumen diameter) in patients with a multi-vessel CAD has not been proven. However, delayed PCI of another lesion and gaining additional information from non-invasive tests is not a widely accepted strategy. When left anterior descending (LAD) coronary artery is one of the affected vessels, selection for surgical revascularisation is most likely. AIM: To assess long-term outcome in patients with multi-vessel CAD and borderline lesions, including LAD, in whom fractional flow reserve (FFR) in all affected vessels was measured and used for selection for PCI or conservative treatment. METHODS: The study group consisted of 16 patients with stable angina (11 males, mean age 60+/-9 years) with 34 lesions localised in the main epicardial coronary arteries [LAD / left main (LM) / right coronary artery (RCA) / intermediate branch (IB) / circumflex artery (Cx) - 15/1/5/5/8] of which at least two were borderline stenoses. Each lesion underwent FFR measurement. "Ad hoc" PCI was performed when FFR was <0.75, and conservative therapy was instituted when FFR was >0.75. RESULTS: Of 34 lesions, in 8 (23%) the FFR value was <0.75 and these lesions were treated with PCI (LAD/IB/Cx - 3/2/3). In the remaining 26 (77%) lesions, FFR was >0.75 and conservative therapy was instituted. During the mean follow-up of 15+/-6 months (range 6-28 months, median 15 months) in 8 of 9 conservatively treated patients no aggravation of anginal symptoms nor other coronary events were observed. One patient developed acute myocardial infarction due to thrombus occluding a borderline LAD lesion. Of 8 lesions treated with PCI (baseline FFR = 0.63+/-0.10 vs post-PCI FFR = 0.92+/-0.08, p=0.0002), in one case an in-stent restenosis in LAD occurred 9 months after PCI. Of a total of 26 lesions which were conservatively treated (mean FFR 0.91+/-0.05), in 2 (7.7%) the progression of CAD was noted. CONCLUSIONS: In patients with multi-vessel CAD and borderline lesions, FFR measurement identifies those, who can be treated conservatively with a good long-term outcome, and prevents unnecessary PCI.     

5-Year Outcomes According to FFR of Left Circumflex Coronary Artery After Left Main Crossover Stenting

ObjectivesThe aim of the current study was to evaluate the long-term clinical impact of fractional flow reserve (FFR) in jailed left circumflex coronary artery (LCx) after left main coronary artery (LM) simple crossover stenting.BackgroundAlthough the provisional side-branch intervention with FFR guidance has been validated for non-LM bifurcation lesions, the outcome of such a strategy in LM bifurcation disease is not well-known.MethodsPatients who underwent LM-to–left anterior descending coronary artery simple crossover stenting and who had FFR measurements in the LCx thereafter were enrolled. A low FFR was defined as ≤0.80. The clinical outcomes were assessed by the 5-year rate of target lesion failure (TLF) (a composite of cardiac death, target-vessel myocardial infarction, or target lesion revascularization).ResultsIn 83 patients, the mean FFR of the LCx after LM stenting was 0.87 ± 0.08, and 14 patients (16.9%) had a low FFR. There was no correlation between the FFR and angiographic % diameter stenosis in jailed LCx (R² = 0.039; p = 0.071) and there was no difference in the angiographic % diameter stenosis in the high and low FFR groups. At 5 years, the low FFR group had a significantly higher rate of TLF than the high FFR group (33.4% vs. 10.7%; hazard ratio: 4.09, 95% confidence interval: 1.15 to 14.52; p = 0.029). However, there was no difference in the clinical outcomes according to the angiographic % diameter stenosis. In a multivariate analysis, a low FFR was an independent predictor of the risk for a 5-year TLF (hazard ratio: 6.49; 95% confidence interval: 1.37 to 30.73; p = 0.018).ConclusionsThe patients with a high FFR in jailed LCx had better 5-year outcomes than those with a low FFR. The FFR measurement in jailed LCx can be helpful in selecting an adequate treatment strategy and may reduce unnecessary complex procedures.     

Evaluation of flow in the left anterior descending coronary artery but not in the left internal mammary artery graft predicts significant stenosis of the arterial conduit

OBJECTIVES: The purpose of this study was to evaluate which Doppler-derived flow index best predicts new distal left anterior descending coronary artery (LAD) stenosis in patients with left internal mammary artery (LIMA) graft. BACKGROUND: The LIMA flow measurement has been proposed to assess graft function, but it may be misleading in case of new distal LAD stenosis and/or competitive flow from native LAD. Distal LAD coronary flow reserve (CFR: hyperemic/baseline peak flow velocity ratio) may be more appropriate. METHODS: The LIMA and distal LAD flow was measured by transthoracic Doppler echocardiography in 96 patients undergoing diagnostic/therapeutic coronary angiography, 7 +/- 4 years after cardiac bypass surgery. The LIMA flow indexes (systolic-to-diastolic peak velocity ratio [SDPVr] >1, diastolic time velocity integral fraction [DTVIf] <0.5, and CFR <2) and LAD CFR <2 were used to predict > or =70% new LAD stenosis. RESULTS: The LAD CFR <2 predicted new LAD stenosis, found in 21 of 77 patients without competitive flow from native LAD, with significantly higher diagnostic accuracy (98%) than LIMA flow indexes (SDPVr >1 = 61%, DTVIf <0.5 = 69%, and CFR <2 = 72%). The LIMA flow indexes were abnormal in 17 of 19 patients with competitive graft flow, but only 5 had graft restriction, and none had significant LAD stenosis. In a multivariate model of new distal LAD stenosis prediction, competitive flow from native LAD reduced the predictive role of LIMA but not of LAD CFR. CONCLUSIONS: In patients without competitive flow from native LAD, LAD CFR is more accurate for the detection of LAD stenosis than LIMA CFR. In patients with competitive graft flow, abnormal LIMA flow patterns and blunted LIMA CFR do not reflect downstream LAD flow as LAD CFR does.     

Fractional flow reserve assessment to determine the indications for myocardial revascularisation in patients with borderline stenosis of the left main coronary artery

INTRODUCTION: Reliable assessment of clinical significance of borderline angiographic lesions found within the left main coronary artery (LM) is often impossible. Measurement of fractional flow reserve (FFR) is commonly used to verify borderline stenoses of the coronary arteries. However, the usefulness of FFR measurements has been validated only for arteries other than the LM. AIM: Evaluation of the measured FFR value in determination of the indications for myocardial revascularisation in borderline LM stenosis. METHODS: The study involved 38 patients aged 55+/-9 years (range 41-74 years) with isolated borderline LM stenosis. Each patient had the measurement of FFR performed during intravenous adenosine infusion at a dose of 140 microg/kg/min. Patients were referred for revascularisation if FFR was <0.75. RESULTS: The mean LM stenosis in quantitative coronary angiography (QCA) was 45+/-10%. FFR<0.75 was found in 18 (47%) patients, whereas 20 (53%) subjects had FFR < or =0.75. In subjects with FFR <0.75 QCA showed significantly lower minimal lumen diameters (MLD) at the site of stenosis (1.84+/-0.45 vs 2.24+/-0.49, p=0.014). Additionally, a significant correlation was found between FFR and MLD (r=0.59, p<0.001). The mean clinical follow-up was 2 years (range 1-3 years). There were two (11%) fatal events in patients with FFR < or =0.75 who underwent CABG. One (5%) patient with FFR >0.75 underwent elective CABG due to progression of LMN stenosis. Moreover, one (5%) patient experienced myocardial infarction not related to borderline stenosis of the LM. CONCLUSIONS: The measurement of FFR confirms the clinical significance of stenosis only in half of the patients with borderline isolated lesion of the left main coronary artery. Withdrawal from intervention in patients with FFR > or =0.75 is safe and is associated with favourable clinical outcomes in two-year follow-up.     

Iatrogenic fistula between the left anterior descending coronary artery and anterior interventricular vein following stenting

We describe the case of a 61-year-old male who had a critical stenosis of the left anterior descending artery (LAD). Intravascular ultrasound demonstrated that the LAD was attached to a large anterior interventricular vein (AIV). After stenting, a fistula was noted between the LAD and AIV, which was successfully sealed by deploying a covered stent. To our knowledge, this is the first case of iatrogenic arteriovenous fistula between the LAD and AIV that occurred following stenting of the LAD.     

Pressure-derived fractional flow reserve to assess serial epicardial stenoses: theoretical basis and animal validation

Background-Fractional flow reserve (FFR) is an index of stenosis severity validated for isolated stenoses. This study develops the theoretical basis and experimentally validates equations for predicting FFR of sequential stenoses separately. Methods and Results-For 2 stenoses in series, equations were derived to predict FFR (FFR(pred)) of each stenosis separately (ie, as if the other one were removed) from arterial pressure (P(a)), pressure between the 2 stenoses (P(m)), distal coronary pressure (P(d)), and coronary occlusive pressure (P(w)). In 5 dogs with 2 stenoses of varying severity in the left circumflex coronary artery, FFR(pred) was compared with FFR(app) (ratio of the pressure just distal to that just proximal to each stenoses) and to FFR(true) (ratio of the pressures distal to proximal to each stenosis but after removal of the other one) in case of fixed distal and varying proximal stenoses (n=15) and in case of fixed proximal and varying distal stenoses (n=20). The overestimation of FFR(true) by FFR(app) was larger than that of FFR(true) by FFR(pred) (0.070+/-0.007 versus 0.029+/-0.004, P<0.01 for fixed distal stenoses, and 0.114+/-0.01 versus 0.036+/-0. 004, P<0.01 for fixed proximal stenoses). This overestimation of FFR(true) by FFR(app) was larger for fixed proximal than for fixed distal stenoses. Conclusions-The interaction between 2 stenoses is such that FFR of each lesion separately cannot be calculated by the equation for isolated stenoses (P(d)/P(a) during hyperemia) applied to each separately but can be predicted by more complete equations taking into account P(a), P(m), P(d), and P(w).     

右冠状动脉狭窄程度对左冠状动脉狭窄患者左室射血分数的影响

目的研究右冠状动脉不同程度狭窄对左冠状动脉狭窄患者左室射血分数（LVEF）的影响。方法根据左冠状动脉病变部位不同,将1 000例左冠状动脉狭窄患者分为左前降支（LAD）狭窄,左回旋支（LCX）狭窄,左主干（LM）狭窄,左前降支+左回旋支（LAD+LCX）狭窄4个系列。每个系列再根据右冠状动脉（RCA）病变程度不同分为RCA正常组（直径狭窄<50%）、RCA非闭塞组（99%>直径狭窄≥50%）和RCA闭塞组（直径狭窄≥99%）,比较分析3组间LVEF的差异。结果在LAD,LCX,LM,LAD+LCX狭窄时,与RCA正常组LVEF相比,RCA非闭塞组LVEF分别下降0.9%,0.3%,3.4%和2.8%;RCA闭塞组LVEF分别下降10.9%,3.7%,6.5%和5.2%。LAD狭窄时,RCA非闭塞组和RCA闭塞组之间LVEF有统计学差异（P<0.01）。结论右冠状动脉病变可在左冠状动脉狭窄的基础上使左室射血分数进一步下降;当左冠状动脉狭窄为闭塞性病变时,影响更为明显。     

Fractional flow reserve [FFR] guided stenting of left main coronary artery in acute coronary syndrome: A single centre experience

The present study assesses the clinical outcomes after left main coronary stenting, using clinical evaluation, angiography, and Fractional Flow Reserve (FFR). A prospective observational study was conducted on 72 patients undergoing left main coronary artery (LMCA) stenting, transthoracic echocardiography, coronary angiography, and percutaneous coronary intervention were done and FFR was recorded. At the end of 6 months, follow up check angiography, FFR study were performed. The stent was placed from LMCA to left anterior descending artery (LAD) artery among 45.83% of patients and 9.72% had from LMCA to Left circumflex artery. The mortality rate was 8.33%. The fractional flow reserve was 0.81 on an average ranging from 0.58 to 0.90. Relatively low incidence of major cardiac event was noted among patients with single vessel disease and ostial LMCA disease.     

右冠状动脉病变对左冠状动脉狭窄患者左心室功能的影响

目的　探讨右冠状动脉病变对左冠状动脉狭窄患者左心室功能的影响及其机制。方法　对比分析左冠状动脉狭窄患者在合并与不合并右冠状动脉病变时的左心室射血分数。结果　与相应部位单纯左冠状动脉狭窄患者相比 ,合并右冠状动脉病变患者左心室射血分数均呈不同程度地下降 ,其中在左前降支、左前降支 +左回旋支狭窄基础上合并右冠状动脉病变时左心室射血分数下降有统计学意义 (P <0 .0 5或 0 .0 1) ,左主干合并右冠状动脉狭窄患者下降幅度最大 ,但无统计学意义。结论　右冠状动脉病变可在单纯左冠状动脉狭窄的基础上使左心室收缩功能进一步恶化 ;当左冠状动脉狭窄部位为左前降支、左主干或左前降支 +左回旋支时 ,对左心室收缩功能影响更为严重     

Severe Aortic Stenosis and Proximal Left Anterior Descending Artery Stenosis: A Positron Emission Tomography/Computed Tomography Assessment Before and After Transcatheter Aortic Valve Implantation

We report the case of an 82-year-old patient with symptomatic severe aortic stenosis and calcified proximal left anterior descending (LAD) artery stenosis who underwent a transfemoral transcatheter aortic valve implantation (TAVI) without complex percutaneous coronary intervention. Before TAVI, a positron emission tomography/computed tomography assessment confirmed a reduced global coronary flow reserve (CFR), more pronounced on the LAD territory. One month post-TAVI, a second positron emission tomography/computed tomography scan showed a normalization of the global CFR and more than a doubling in the LAD territory. This case illustrates that mechanisms other than vessel stenosis may play an important role in CFR in the setting of aortic stenosis.     

Significance of exercise-induced ST changes in leads aVR,V5, and V1. Discrimination of patients with single- or multivessel coronary artery disease

BACKGROUND: It is known that exercise-induced ST-segment elevation in lead V1 (V1-E) detects left anterior descending (LAD) stenosis. It was also postulated that ST elevation in aVR and simultaneous ST depression in V5 (aVR-E + V5-D) is a marker of ischemia due to significant stenosis of the LAD in patients with single-vessel disease. HYPOTHESIS: This study was undertaken to investigate the significance of the concomitant appearance of both electrocardiographic (ECG) ischemic markers, and of each of them alone during exercise, to detect either LAD stenosis as single-vessel coronary artery disease (CAD), or multivessel CAD involving LAD stenosis. METHODS: A total of 196 consecutive patients (152 men and 44 women, mean age 54 +/- 7 years) with at least one of these ECG markers, who underwent treadmill exercise testing with the Bruce protocol and coronary arteriography, were studied. RESULTS: Patients were divided into three groups. In Group A (83 patients with V1-E + aVR-E & V5-D), 93% of patients with single-vessel disease had significant LAD stenosis (p<0.001), whereas 75% of patients with double-vessel disease had significant stenoses of the LAD and the left circumflex (LCx) coronary arteries (p<0.01). In Group B (97 patients with aVR-E & V5-D but without V1-E), 43% of patients with single-vessel disease had significant LAD stenosis (p<0.08), whereas 85% of patients with double-vessel disease had significant stenoses of the LAD and the right coronary artery (RCA) (p<0.01). In Group C (16 patients with only V1-E), 60% of patients with single-vessel disease had significant LAD stenosis (p<0.05), whereas 75% of patients with double-vessel disease had significant LAD and LCx stenoses (p<0.05). CONCLUSIONS: The concomitant appearance of exercise-induced ST elevation in lead V1, ST elevation in lead aVR, and ST depression in lead V5, as well as the isolated appearance of ST elevation in lead V1 detect significant LAD stenosis as single-vessel disease, or significant stenoses of LAD and LCx arteries in patients with double-vessel disease, whereas the appearance of ST elevation in aVR & ST depression in V5 but without ST elevation in V1 correlates strongly with significant LAD and RCA stenoses and usually indicates double-vessel disease.     

Catheter-induced dissection of the left main coronary artery,the nemesis of an invasive cardiologist A case report and review of the literature

An elderly gentleman had a dissection of the left main coronary artery (LMCA) during coronary angiography. There were critical lesions in the left anterior descending (LAD) and left circumflex arteries. Both the LMCA and the LAD lesions were successfully stented in the same sitting. Thereafter the patient remained symptom free and the six-month follow-up angiogram revealed good angioplasty results in both lesions. We report this case for two reasons - first, acute dissection of the LMCA is a rare but devastating complication of selective coronary angiography and the situation becomes graver if the branch vessels have critical stenosis; that this could be managed percutaneously needs to be highlighted, and second, the case offers an opportunity to review literature pertinent to this awesome occurrence in the catheterization laboratory.