ABSTRACT
ObjectiveThe fractional flow reserve （FFR） computed from coronary computed tomographic （CT） angiograms makes it possible to noninvasively assess coronary artery disease， but the impact of plaque on FFR derived from computed tomography angiography （CTA） is still unknown. The study used invasive FFR as the reference standard to analyze the impact of plaque on coronary computed tomography angiography （CCTA）-based quantitative flow ratio （CT-QFR）. MethodsThe retrospective study included 108 patients with suspected coronary heart disease （CHD） who underwent both CCTA and FFR within 60 days. CCTA images were analyzed by the software. We obtained the CT-QFR of target vessels， perfomed the quantitative and qualitative analyses on target vascular plaques， including total plaque volume （TPV）， plaque burden， calcified plaque volume （CPV）， fibrous plaque volume （FPV）， lipid plaque volume （LPV）， and the presence or absence of high-risk plaque. ResultsAccording to the difference between CT-QFR and FFR at blood vessel level， 137 target vessels of 108 patients were divided into the overestimated group （difference＞0.03， n＝29）， reference group （-0.03≤difference≤0.03， n＝88） and underestimated group （difference＜-0.03， n＝20）. The underestimated group （14.81mm3） presented higher LPV than overestimated group （1.97mm3， P < 0.05）. There was a negative correlation between LPV and the difference （P＜0.05）. ConclusionsWhen CT-QFR is used to estimate hemodynamics of coronary artery stenosis， the presence of lipid plaque may underestimate the virtual FFR.
ABSTRACT
Cardiovascular disease is one of the most serious diseases endangering human life and health. In China, 2 out of every 5 people die of cardiovascular diseases. Myocardial ischemia is one of the important cardiovascular diseases. Fractional flow reserve (FFR) is used to quantify myocardial ischemia in epicardial stenoses. Index of microvascular resistance (IMR) is an invasive index for quantitative evaluation of coronary microcirculation. Traditional FFR and IMR measurements rely on guide wires to perform interventional measurements under the maximum hyperemia state,so as to assist the diagnosis of myocardial ischemia clinically. Coronary angiography-derived FFR and IMR without using invasive pressure-wire measurement, hyperemic stimulus and contraindications can assist the diagnosis and treatment of percutaneous coronary intervention by fast simultaneous calculation of FFR and IMR. In this review, the research progress of coronary angiography-derived FFR and IMR as well as other coronary physiological evaluation in recent years were summarized. It is of great clinical value to further study the combination of coronary angiography-derived FFR and IMR in functional research of coronary circulation from macro to micro.
ABSTRACT
Objective To establish a method for non-invasive calculation of fractional flow reserve (FFRCT) with the shape resistance of coronary artery stenosis as boundary condition, and to verify the accuracy of this method. Methods CT angiography images of 16 patients with coronary artery disease were reconstructed; the mathematical model of shape resistance was established by considering the minimum cross-sectional area and the length of stenosis of coronary artery stenosis, the induced pressure difference as the boundary condition was applied to calculate FFRCT (named as shape resistance method ). The values of clinical FFR were taken as the gold standard, previous diameter method and volume method were taken as control method, and accuracy of shape resistance method was investigated from the aspects of mean error rate, accuracy rate, sensitivity rate, positive prediction rate and negative prediction rate. Results The mean error rate of calculated FFRCT by the diameter method, volume method and shape resistance method were 11.76%, 10.46%, 4.82%, the accuracy rates were 85%, 65%, 90%, the sensitivity rates were 87.5%, 66.7%, 87.5%, the positive prediction rate were 75%, 25%, 87.5%, respectively, while the negative prediction rates were all 91.6%. Conclusions The established shape resistance method is better than the diameter method and volume method from the aspects of mean error rate, accuracy rate, sensitivity rate and positive prediction rate; the FFRCT based on the shape resistance method and clinical FFR have good consistency, and this work may provide a new way for the calculation and application of FFRCT.
ABSTRACT
Introducción: El estudio hemodinámico de una estenosis coronaria de severidad intermedia mediante la prueba de fracción de flujo de reserva (FFR) coronaria es fundamental en términos de eventos cardiovasculares principales a corto y largo plazo. Actualmente, no se ha publicado en este contexto la aplicación intracoronaria de levosimendán. Objetivos: Determinar los efectos hemodinámicos de la administración intracoronaria de levosimendán como vasodilatador en la prueba FFR, comparado contra adenosina intracoronaria. Material y métodos: Se estudiaron mediante FFR 48 lesiones intermedias en las coronarias epicárdicas principales. Resultados: De las 48 lesiones valoradas con FFR en relación con la aplicación de adenosina versus levosimendán intracoronarios, el porcentaje de estenosis coronaria fue del 55.83 (± 11.64), FFR adenosina intracoronaria 0.8633 (± 0.1130) y FFR levosimendán intracoronario 0.8652 (± 0.1090); coeficiente de correlación 0.9859 y correlación cuadrática 0.9720. Demostrando que la inducción de vasodilatación es semejante, incluyendo casos positivos para revascularización con relación FFR < 0.80. Conclusiones: El levosimendán intracoronario en la prueba FFR presentó semejanza en la valoración de las estenosis coronarias intermedias, comparado con adenosina intracoronaria. El levosimendán representa una alternativa favorable en la inducción de hiperemia coronaria, para normar decisiones de revascularización mediante asistencia fisiológica.
Aims: The hemodynamic study of a coronary stenosis of intermediate severity, by testing fraction flow reserve (FFR) is essential in terms of major cardiovascular events in the short and long term. Currently not published in this context the intracoronary application of levosimendan. Objectives: To determine the hemodynamic effects of intracoronary administration of levosimendan, a vasodilator in the FFR test, compared with intracoronary adenosine. Material and methods: Were evaluated by FFR, 48 intermediate lesions in major epicardial coronary arteries. Results: Of the 48 lesions with FFR assessed, the application of adenosine versus intracoronary levosimendan, the percentage of coronary stenosis was 55.83 (± 11.64), intracoronary adenosine FFR 0.8633 (± 0.1130) and 0.8652 FFR intracoronary levosimendan (± 0.1090) correlation coefficient of 0.9859 and 0.9720 quadratic correlation. Demonstrating that induction of vasodilatation is similar, including revascularization positive cases compared FFR < 0.80. Conclusions: Intracoronary levosimendan in the FFR test showed similarity in the assessment of intermediate coronary stenosis compared with intracoronary adenosine. Levosimendan is an excellent alternative in the induction of coronary hyperemia decisions to regulate physiological revascularization with assistance.
ABSTRACT
BACKGROUND AND OBJECTIVE: Precise assessment of lesion severity is fundamental for the clinical decision making in the patients with coronary artery disease. Coronary angiography has limitation to projection imaging techniques. Intravascular ultrasound (IVUS) has been known to be a gold standard of morphological severity of coronary stenosis. Fractional flow reserve (FFR) is known to be a lesion specific functional index of epicardial stenosis that can be derived from intracoronary pressure assessed during maximal vasodilation. The objective of this study was to investigate the validity of fractional flow reserve for stenosis severity in comparison with IVUS. METHODS: The study population consisted of 24 patients with angina pectoris (M:F=19:5, age: 58+/-12 yrs). The IVUS and intracoronary pressure wire performed at 26 lesions after diagnostic coronary angiography. We measured angiographical diameter stenosis (DST), minimal luminal diameter (MLD), minimal luminal area (MLA) and reference area stenosis (r-AST). FFR was defined by the ratio of distal mean coronary pressure (Pd) to aortic mean pressure (Pa). RESULTS: FFR showed significant correlation with both r-AST (r=-0.93, p<0.00001) than DST (r=-0.79, p<0.0001). When the lesions with MLD less than 1.1 mm were excluded, considering the limitation of IVUS for the thickness of its catheter, FFR showed excellent correlation with r-AST with higher correlation coefficient (r=-0.96, p<0.00001). FFR showed significant correlation with MLA (r=0.87, p=0.0001) or MLD (r=0.83, p=0.0005). CONCLUSION: FFR with excellent correlation with r-AST measured by IVUS seems to be a useful lesion specific functional index for the assessment of coronary stenosis in angina patients.