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Fractional Flow Reserve, Myocardial* ; Myocardial Infarction*

Angiography ; Fractional Flow Reserve, Myocardial ; physiology ; Humans ; Tomography, Optical Coherence

OBJECTIVEThe objective was to delineate the current knowledge of fractional flow reserve (FFR) in terms of definition, features, clinical applications, and pitfalls of measurement of FFR.

DATA SOURCESWe searched database for primary studies published in English. The database of National Library of Medicine (NLM), MEDLINE, and PubMed up to July 2014 was used to conduct a search using the keyword term "FFR".

STUDY SELECTIONThe articles about the definition, features, clinical application, and pitfalls of measurement of FFR were identified, retrieved, and reviewed.

RESULTSCoronary pressure-derived FFR rapidly assesses the hemodynamic significance of individual coronary artery lesions and can readily be performed in the catheterization laboratory. The use of FFR has been shown to effectively guide coronary revascularization procedures leading to improved patient outcomes.

CONCLUSIONSFFR is a valuable tool to determine the functional significance of coronary stenosis. It combines physiological and anatomical information, and can be followed immediately by percutaneous coronary intervention (PCI) if necessary. The technique of FFR measurement can be performed easily, rapidly, and safely in the catheterization laboratory. By systematic use of FFR in dubious stenosis and multi-vessel disease, PCI can be made an even more effective and better treatment than it is currently. The current clinical evidence for FFR should encourage cardiologists to use this tool in the catheterization laboratory.

BACKGROUND AND OBJECTIVES: The purposes of this study are 1) to investigate the relationship between resting baseline Pd/Pa, determined by the ratio of the pressures proximal (Pa) and distal (Pd) to the target lesion before, inducing hyperemia and fractional flow reserve (FFR) and 2) to identify a resting baseline Pd/Pa range that might reliably preclude the need for hyperemic induction. SUBJECTS AND METHODS: A total of 622 pressure wire data sets obtained from intermediate stenotic lesions were analyzed. RESULTS: There was a good linear relationship between resting baseline Pd/Pa and FFR (r=0.746, p<0.001). Receiver-operating characteristic curves of the resting baseline Pd/Pa with FFR < or =0.80 as the reference variable showed an area under the curve of 0.89 (95% confidence intervals 0.863-0.914, p<0.001) with a diagnostic accuracy of 82.3% when the resting baseline Pd/Pa was < or =0.92. These results showed that certain cutoff values can reliably predict FFR, whether positive or negative. The resting baseline Pd/Pa >0.95 (n=257, 41.3%) had a negative predictive value (NPV) of 98.1% and a sensitivity of 97.3%. the resting baseline Pd/Pa < or =0.88 (n=65, 10.5%) had a positive predictive value (PPV) of 96.2% and a specificity of 99.8%. These were consistent regardless of coronary vessel, lesion location, lesion length, or degree of stenosis. CONCLUSION: In intermediate lesions, the resting baseline Pd/Pa was linearly related to FFR. A certain range of the resting baseline Pd/Pa values had an excellent NPV with high sensitivity or excellent PPV with high specificity for determining the lesion significance.
Coronary Vessels ; Fractional Flow Reserve, Myocardial ; Glycosaminoglycans ; Hyperemia ; Sensitivity and Specificity

Fractional Flow Reserve, Myocardial ; physiology ; Humans ; Mesenteric Ischemia ; physiopathology

Coronary atherosclerotic heart disease is a heart disease caused by coronary artery stenosis or obstruction, resulting in myocardial ischemia, hypoxia or necrosis. Its examination methods include electrocardiogram, hematological examination, coronary CT, coronary angiography and intravascular imaging technology, etc. In recent years, blood Fractional Flow Reserve(FFR) has been widely used to measure the degree of coronary artery stenosis in the treatment of coronary heart disease. Based on the related literature at home and abroad, elaborated the FFR measurements of coronary artery stenosis degree background significance, basic principle and implementation method, on the basis of inductive expounds the FFR examination of clinical research and the advantages and disadvantages, at the same time a preliminary prospect on the development of technology of FFR iFR-the future instantaneous waveform ratio and the functional SYNTAX score has a broad space for development.
Coronary Artery Disease ; Fractional Flow Reserve, Myocardial ; Humans

BACKGROUND AND OBJECTIVES: Lesions of vascular bifurcation and their treatment outcomes have been evaluated by anatomical and physiological methods, such as intravascular ultrasound and fractional flow reserve (FFR). However, local changes in flow dynamics in lesions of bifurcation have not been well evaluated. This study aimed at evaluating changes in the local flow patterns of bifurcation lesions. MATERIALS AND METHODS: Eight (n=8) representative simulation-models were constructed: 1 normal bifurcation, 5 main-branch (MB) stenting models with various side-branch (SB) stenoses (ostial or non-ostial 75% diameter stenosis with 1- or 2-cm lesion lengths, ostial 75% diameter stenosis caused by carina shift), and 2 post-kissing models (no or 50% SB residual stenosis). Pressure, velocity, and wall shear stress (WSS) profiles around the bifurcation sites were investigated using computational fluid dynamics. RESULTS: Post-stenting models revealed significant pressure drop in the SB (FFR<0.75), excluding the carina shift model (FFR=0.89). In the post-kissing models, there was no significant pressure drop. All post-stenting models revealed eccentric low velocity flow patterns and areas of low WSS, primarily in the lateral wall on distal MB. Post-kissing angioplasty improved pressure drop in the SB but resulted in alteration of flow distribution in the MB. In the carina shift model, kissing ballooning resulted in deteriorated local flow conditions due to increased area of low velocity and WSS. CONCLUSION: This study suggests that the most commonly used bifurcation intervention strategy may cause local flow disturbances, which may partially explain high restenosis and event rates in patients with bifurcation lesions.
Angioplasty ; Blood Flow Velocity ; Constriction, Pathologic ; Fractional Flow Reserve, Myocardial ; Humans ; Hydrodynamics ; Shear Strength ; Stents

BACKGROUND AND OBJECTIVES: Lesions of vascular bifurcation and their treatment outcomes have been evaluated by anatomical and physiological methods, such as intravascular ultrasound and fractional flow reserve (FFR). However, local changes in flow dynamics in lesions of bifurcation have not been well evaluated. This study aimed at evaluating changes in the local flow patterns of bifurcation lesions. MATERIALS AND METHODS: Eight (n=8) representative simulation-models were constructed: 1 normal bifurcation, 5 main-branch (MB) stenting models with various side-branch (SB) stenoses (ostial or non-ostial 75% diameter stenosis with 1- or 2-cm lesion lengths, ostial 75% diameter stenosis caused by carina shift), and 2 post-kissing models (no or 50% SB residual stenosis). Pressure, velocity, and wall shear stress (WSS) profiles around the bifurcation sites were investigated using computational fluid dynamics. RESULTS: Post-stenting models revealed significant pressure drop in the SB (FFR<0.75), excluding the carina shift model (FFR=0.89). In the post-kissing models, there was no significant pressure drop. All post-stenting models revealed eccentric low velocity flow patterns and areas of low WSS, primarily in the lateral wall on distal MB. Post-kissing angioplasty improved pressure drop in the SB but resulted in alteration of flow distribution in the MB. In the carina shift model, kissing ballooning resulted in deteriorated local flow conditions due to increased area of low velocity and WSS. CONCLUSION: This study suggests that the most commonly used bifurcation intervention strategy may cause local flow disturbances, which may partially explain high restenosis and event rates in patients with bifurcation lesions.
Angioplasty ; Blood Flow Velocity ; Constriction, Pathologic ; Fractional Flow Reserve, Myocardial ; Humans ; Hydrodynamics ; Shear Strength ; Stents

OBJECTIVETo evaluate the long-term clinical outcomes of fractional flow reserve (FFR)-guided versus intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) for intermediate coronary lesions.

METHODSA total of 226 patients with 293 intermediate coronary artery lesions (stenosis of 40%-70%) confirmed by coronary angiography were randomized into 3 groups to undergo PCI for a minimal lumen cross sectional area (MLA)<4 mm(2) (IVUS group, 98 lesions) or for a FFR<0.80 (FFR group, 101 lesions), or to receive standard medical treatment (medication group, 94 lesions). The primary outcome was major adverse cardiac events including death, myocardial infarction, and ischemia-driven target vessel revascularization at 1 year after the index procedure.

RESULTSThe baseline percent diameter stenosis and lesion length were similar between the 3 groups, but more patients in IVUS group than in FFR group received PCI (P<0.001). No significant difference was found in the incidence of major adverse cardiac events between the 3 groups (P=0.182).

CONCLUSIONBoth FFR- and IVUS-guided PCI strategy for intermediate coronary artery disease are associated with favorable outcomes, but IVUS-guided PCI based on the single index of MLA can increase the rate of revascularization therapy.

BACKGROUND: Intravascular ultrasound (IVUS) is one of the golden standards for the assessment of optimal angioplasty. Pressure-derived myocardial fractional flow reserve (FFRmyo) is a lesion-specific functional index of epicardial conduit and may be particularly useful for the assessment of optimal coronary angioplasty. The purpose of this study was to assess IVUS parameters and FFRmyo after successful angioplasty on coronary angiogram and compare them between balloon and stent group. METHODS: The study population consisted of 28 patients who underwent revascularization (14 cases of balloon angioplasty only, 14 cases of angioplasty with stent) from Jan. 1999 to Aug. 2000 at Inha University Hospital. After successful angioplasty on coronary angiogram, we measured minimal luminal diameter (MLD), minimal luminal area (MLA), lesion area stenosis (l-AST) and reference area stenosis (r-AST) with IVUS imaging. And we calculated FFRmyo from the ratio of mean coronary pressure distal to the stenosis (Pd) to the aortic mean pressure (Pa) during maximum coronary hyperemia (Pd/Pa). RESULTS: There was significant difference of MLD (2.2+/-0.4 vs 2.6+/-0.3), MLA (4.4+/-1.1 vs 6.4+/-1.7), r-AST (43.7+/-9.2 vs 29.8+/-9.4) and FFRmyo (0.89+/-0.07 vs 0.93+/-0.03) between balloon and stent group. All IVUS parameters (MLD, MLA, r-AST) are well correlated with FFRmyo after angioplasty (r=0.52, p<0.05, r=0.48, p<0.05 and r=-0.72, p<0.05 respectively). By multiple regression analysis, r-AST showed the best correlation with FFRmyo among IVUS parameters. CONCLUSION: Coronary angioplasty with stent showed more favorable MLD, MLA, r-AST and FFRmyo than balloon angioplasty. FFRmyo may be seemed to be alternative to IVUS for estimating the result of coronary angioplasty.
Angioplasty* ; Angioplasty, Balloon ; Constriction, Pathologic ; Fractional Flow Reserve, Myocardial ; Humans ; Hyperemia ; Phenobarbital ; Stents ; Ultrasonography*