Utility of myocardial fractional flow reserve for prediction of restenosis following sirolimus-eluting stent implantation

Drug-eluting stents reduce restenosis due to neointimal growth suppression. Considering long-term outcomes, it is both difficult and important to predict drug-eluting stent restenosis. Thus, this study was designed to examine the utility of myocardial fractional flow reserve (FFR) as a predictor of sirolimus-eluting stent (SES) restenosis. Thirty-three patients (35 lesions) were enrolled. Upon completion of SES implantation, FFR was obtained under hyperemia. At 8 months of follow-up, coronary angiography revealed that five lesions had restenosis. Percent diameter stenosis (restenosis 68.7 ± 12.8% vs. non-restenosis 68.7 ± 12.4%, p = 0.78) and lesion length (restenosis 15.8 ± 9.4 mm vs. non-restenosis 14.4 ± 9.2 mm, p = 0.60) were similar. At post-intervention, percent diameter stenosis (restenosis 16.4 ± 6.1% vs. non-restenosis 14.0 ± 7.4%, p = 0.48) and minimum stent area (restenosis 6.01 ± 1.08 mm2 vs. non-restenosis 6.27 ± 1.85 mm2, p = 0.92) were also equivalent. However, proximal edge lumen area was smaller (restenosis 4.24 ± 1.40 mm2 vs. non-restenosis 7.73 ± 2.64 mm2, p = 0.004) and FFR was lower in the restenosis group (restenosis 0.81 ± 0.12 vs. non-restenosis 0.92 ± 0.06, p = 0.029). SES patients with restenosis had a lower FFR post stent deployment, suggesting the decreased FFR may be a useful predictor for SES restenosis.     

Use of fractional flow reserve versus stress perfusion scintigraphy after unstable angina. Effect on duration of hospitalization,cost, procedural characteristics,and clinical outcome

OBJECTIVES: The present study sought to determine the value of fractional flow reserve (FFR) compared with stress perfusion scintigraphy (SPS) in patients with recent unstable angina/non-ST-segment elevation myocardial infarction (UA/NSTEMI). BACKGROUND: Fractional flow reserve, an invasive index of stenosis severity, is a reliable surrogate for SPS in patients with normal left ventricular function. An FFR > or = 0.75 can distinguish patients after myocardial infarction (MI) with a positive SPS from those with a negative SPS. However, the use of FFR has not been investigated after UA/NSTEMI. METHODS: Seventy patients who had recent UA/NSTEMI and an intermediate single-vessel stenosis were randomized to either SPS (n = 35) or FFR (n = 35). Patients in the SPS group were discharged if the SPS revealed no ischemia, whereas those in the FFR group were discharged if the FFR was > or = 0.75. Patients with a positive SPS and those with an FFR <0.75 underwent percutaneous transluminal coronary angioplasty. The use of FFR markedly reduced the duration and cost of hospitalization compared with SPS (11 +/- 2 h vs. 49 +/- 5 h [-77%], p < 0.001; and 1,329 US dollars +/- 44 US dollars vs. 2,113 US dollars +/- 120 US dollars, respectively, p < 0.05). There were no significant differences in procedure time, radiation exposure time, or event rates during follow-up, including death, MI, or revascularization. CONCLUSIONS: These data indicate that: 1) the use of FFR in patients with recent UA/NSTEMI markedly reduces the duration and cost of hospitalization compared with SPS; and 2) these benefits are not associated with an increase in procedure time, radiation exposure time, or clinical event rates.     

Clinical significance of fractional flow reserve for evaluation of functional lesion severity in stent restenosis and native coronary arteries

OBJECTIVE: Fractional flow reserve (FFR) is a valid surrogate for hemodynamic significance in stenotic native coronary arteries, but its validity in patients with coronary stent restenosis is unknown. DESIGN: Prospective. SETTING: University hospital. PATIENTS: We studied 42 patients (mean age +/- 1 SD, 62 +/- 10 years) with stent restenosis and 57 patients (mean age, 61 +/- 12 years) with a native coronary lesion. All patients demonstrated a single coronary lesion of intermediate severity (stenosis diameter, 40 to 70%). Determination of FFR and quantitative angiography of the stenosis were performed. RESULTS: Stenosis diameter was comparable in both groups (native, 52 +/- 11%; stent, 52 +/- 9%; not significant [NS]). FFR was lower in stent restenosis (0.77 +/- 0.15 vs 0.82 +/- 0.12, p < 0.05) and more often pathologic with an FFR < 0.75 (48% vs 26%, p < 0.05) compared to native coronary stenosis. However, the area under the receiver operating characteristic curve for native stenosis was 0.82 (95% confidence interval [CI], 0.71 to 0.94) and for stent restenosis was 0.84 (95% CI, 0.71 to 0.97; NS). In patients with an FFR > 0.75, there was no adverse coronary event that was related to the stented lesion in the subsequent 6 months. CONCLUSIONS: The threshold of stenosis diameter of coronary lesions for pathologic FFR measurement (FFR < 0.75) is similar for stent restenosis and native coronary stenosis. Thus, FFR measurement seems to be applicable for decision making in patients with stent restenosis.     

The role of fractional flow reserve to guide stent implantation

In routine clinical practice, a sizeable proportion of patients with suspected coronary artery disease (CAD) undergo coronary angiography without prior non-invasive functional evaluation. In this situation, the decision wheter to perform revascularization is taken solely on the basis of angiographic parameters, which are often limited in assessing the lesions that are functionally significant and ultimately responsible for patients' symptoms. Fractional flow reserve (FFR) is a validated method for assessing hemodynamic significance of coronary stenoses based on the use of pressure wires and assessment of hyperemic pressure gradients across coronary lesions. FFR can guide clinical decision making in several anatomical settings: e.g. intermediate stenosis, left main stenoses, multivessel disease, bifurcation lesions. Treatment strategies guided by FFR have been shown to be equally safe and more efficacious than angiography-guided PCI. FFR is readily available in the catheterization laboratory, and can be easily measured during coronary angiography. FFR represents a unique tool for interventional cardiologists to combine anatomical and functional information, allowing the selection of optimal revascularization strategy in patients with CAD.     

Relation of fractional flow reserve after drug-eluting stent implantation to one-year outcomes

Patients still present with drug-eluting stent (DES) failure despite an angiographically successful implantation. The aim of the present study was to investigate the relation between the fractional flow reserve (FFR) measured after DES implantation and the clinical outcomes at 1 year. A total of 80 patients (mean age 62 years, 74% men, 99 DESs) underwent coronary pressure measurement at maximum hyperemia after successful DES implantation. The composite of major adverse cardiac events (MACE), including death, myocardial infarction, and ischemia-driven target vessel revascularization was evaluated at 1 year. The patients were divided into 2 groups (low-FFR group, FFR ≤0.90 and high-FFR group, FFR >0.90) according to the median FFR. The mean poststent percent diameter stenosis was 11 ± 5% in the low-FFR group and 12 ± 3% in the high-FFR group (p = 0.31). Left anterior descending coronary artery lesions were more frequent in the low-FFR group than in the high-FFR group (82% vs 55%, p = 0.02). The mean stent length was greater in the low-FFR group than in the high-FFR group (38 ± 18 vs 28 ± 13 mm, p = 0.01). Six cases (7.5%) of MACE occurred during the 1-year follow-up. The rate of MACE was 12.5% in the low-FFR group and 2.5% in the high-FFR group (p <0.01). Receiver operating characteristic curves revealed 0.90 as the best cutoff of FFR after DES implantation for the prediction of 1-year MACE. In conclusion, a poststent FFR of ≤0.90 correlated with a greater adverse event rate at 1 year.     

Myocardial fractional flow reserve

Revascularization of coronary artery lesions should be based on objective evidence of ischemia, as recommended by the guidelines of the European Society of Cardiology. However, even in the case of stable coronary artery disease and elective percutaneous coronary intervention (PCI), pre-procedural noninvasive stress test results are available in a minority of patients only. It is common practice for physicians to make decisions on revascularization in the catheterization laboratory after a cursory review of the angiogram, despite the well-recognized inaccuracy of such an approach. Myocardial fractional flow reserve (FFR) measured by a coronary pressure wire is a specific index of the functional significance of a coronary lesion, with superior diagnostic accuracy for the detection of ischemia than any noninvasive stress test. FFR trials on patients with single and multivessel disease, such as the DEFER and FAME studies, have demonstrated that the clinical benefit of PCI with respect to patient outcome is greatest when revascularization is limited to lesions inducing ischemia, whereas lesions not inducing ischemia should be treated medically.     

Utility of the fractional flow reserve in the evaluation of angiographically moderate in-stent restenosis.

AIMS: The evaluation of in-stent restenosis (ISR) is usually based on angiographic quantification. This evaluation is sometimes difficult and it has not an accurate clinical correlation. Fractional flow reserve (FFR) measured by intracoronary pressure wire has demonstrated its value in determining the functional repercussion of coronary stenosis. The aim of this study was to evaluate the relation between quantitative angiography-FFR in borderline in-stent restenotic lesions and the accuracy of FFR in deciding the treatment of ISR. METHODS AND RESULTS: Quantitative angiographic values of 65 lesions in 62 patients with angiographically moderate ISR are compared with the FFR value obtained by pressure wire. An FFR value<0.75 was considered significant. Patients with non-revascularized ISR (FFR > or = 0.75) were clinically followed during a year. An FFR value > or = 0.75 was obtained in 41 lesions (63%), 21 of them with stenosis > or = 50%. The co-efficient of correlation between parameters of quantitative angiography and FFR value was <0.5. No events related to the non-treated lesions were observed. CONCLUSIONS: A poor correlation between angiographic quantification and FFR of moderate ISR was found. Conservative management of moderate 40-70% in-stent restenotic lesions with FFR value > or = 0.75 is safe avoiding unnecessary revascularizations based solely on the angiography.     

Prediction of in-stent restenosis by measurement of fractional flow reserve and the influence of diabetes mellitus

OBJECTIVES: This study tried to predict in-stent restenosis by the measurement of fractional flow reserve and to evaluate the effect of diabetes mellitus control on the relationship between in-stent restenosis and fractional flow reserve. METHODS: Fractional flow reserve was measured in 62 patients (mean age 61 +/- 9 years, 32 with angina pectoris and 30 with myocardial infarction) after stent implantation. The patients were divided into three groups according to the value of HbA1c and fasting blood sugar (FBS): Group P (HbA1c > or = 6.5% or FBS > or = 126 mg/dl, n = 15), Group G (6.5% > HbA1c > or = 5.8% or 126 > FBS > or = 100 mg/dl, n = 12), and Group N (HbA1c < 5.8% and FBS < 100 mg/dl, n = 35). The relationship between fractional flow reserve at the end point of stent implantation and target lesion revascularization (TLR) was evaluated. RESULTS: In all patients, fractional flow reserve was 0.89 +/- 0.17 and percentage diameter stenosis was 17.6 +/- 11.6% after stent implantation. The TLR rate was 21%. Fractional flow reserve was significantly lower in patients with TLR (0.85 +/- 0.08 vs 0.91 +/- 0.06, p < 0.01). Fractional flow reserve was significantly lower in patients with TLR in Groups N and G (Group N: 0.85 +/- 0.04 vs 0.91 +/- 0.06, p < 0.05, Group G: 0.77 +/- 0.06 vs 0.91 +/- 0.05, p < 0.01). Fractional flow reserve showed no significant difference between patients with TLR and without TLR in Group P (0.85 +/- 0.10 vs 0.87 +/- 0.08, p = NS). In patients with optimal results (fractional flow reserve > or = 0.90), TLR rate was 60% in Group P, 0% in Group G and 0% in Group N. CONCLUSIONS: Fractional flow reserve after stent implantation is useful for the prediction of TLR in patients without diabetes mellitus. However, diabetic control in patients with diabetes mellitus might be attributable to TLR rather than fractional flow reserve.     

无创血流储备分数的研究进展

传统的冠状动脉造影不能准确反映冠心病患者冠状动脉病变程度,血流储备分数(FFR)是诊断冠状动脉缺血病变的“金标准”,但需要使用压力导丝和血管扩张剂,会增加有创操作风险、手术时间和诊疗费用,限制了其在临床实践中的应用。近年来出现的无创FFR技术无需压力导丝和血管扩张剂,基于流体力学原理,利用冠状动脉CT或冠状动脉造影图像即可测定FFR,避免了有创FFR的不足,在临床研究中也表现出了良好的诊断价值,本文对无创FFR技术进行综述。     

Normalisation of abnormal coronary fractional flow reserve associated with myocardial bridging using an intracoronary stent

Although intracoronary stenting procedures have been advocated for the successful treatment of myocardial ischaemia associated with myocardial bridging, the physiological rationale for this approach remains unexplored. The case of a 70 year old man with symptoms of cardiac ischaemia associated with a left anterior descending coronary artery bridge is described, where use of an intracoronary stent abolished the angiographic abnormalities and also restituted pronounced abnormalities of coronary fractional flow reserve.


Keywords: angioplasty; myocardial bridge; coronary flow reserve; stent     

Normalization of coronary fractional flow reserve with successful intracoronary stent placement to a myocardial bridge

Although myocardial bridge is asymptomatic in most patients, it can lead to myocardial ischemia, myocardial infarction, cardiac arrhythmias, and sudden death. We successfully treated a myocardial bridge, which caused a severe stenosis in left anterior descending (LAD) artery together with myocardial ischemia and disturbance in intracoronary hemodynamics, with stent implantation.