View clinical trials related to Fractional Flow Reserve.
Filter by:This is a randomized, non-inferiority, crossover investigation comparing the Direct Wire Pacing (DWP) versus standard method to measure Fractional Flow Reserve (FFR) in subjects with FFR indications. All subjects requiring on a clinical basis a pressure wire assessment of coronary artery stenosis(es) will be eligible to take part in the study.
The background for performing the present study is to compare the mass calculations by CT scanning and by invasive absolute blood flow measurements and thereby corroborating both methods.
Primary objective: To document change in translesional pressure gradients (TLPGs) and ratios (fractional flow reserve) using the NAVVUS RXi catheter following endovascular treatment for symptomatic lower extremity peripheral arterial disease. Secondary objectives: - Evaluation of correlation of the ABI and TBI and TLPGs at baseline and following endovascular therapy - Evaluation of the correlation between the change in WIQ, TCOMs, wound size and change in TLPGS - Evaluation of correlation between lesion severity by QVA (MLD, % diameter stenosis) and TLPGs - Evaluation of baseline MLA, MLD, plaque burden by intravascular ultrasound (optional) and TLPGs
Instantaneous wave-free ratio (iFR™) is a novel non-hyperaemic index of the functional significance of a coronary stenosis. Previous studies have shown variable levels of correlation with the established hyperaemic index FFR. In addition it has been proposed that iFR™ has superior diagnostic accuracy when compared to mean whole cardiac cycle Pd/Pa which can also be used to predict FFR. We plan to undertake a prospective clinical study in consecutive patients already undergoing FFR assessment in the cardiac catheterisation laboratory to compare the ability of iFR™ and Pd/Pa (both measured using the proprietary Volcano system) to predict FFR. We will explore the level of misclassification of flow limiting disease that results from use of iFR™ and resting Pd/Pa employed using either binary cut-off algorithms or in a hybrid decision making protocol. We plan to analyse 260 vessels over a 18 month period. Hyperaemia will be induced by intravenous adenosine (140 ug/kg/min) administered wherever possible via an antecubital vein. Intra-coronary nitrates will also be given in line with the standard care procedure for FFR measurement. Final clinical decisions following coronary physiology will be based on steady state FFR.
Fractional flow reserve (FFR) is an established invasive method for assessing the physiological significance of coronary artery stenosis. Adenosine, an important endogenous regulator of coronary blood flow during both stress and ischemia, is widely used to achieve conditions of stable hyperemia required for measurement of FFR. Studies in healthy volunteers and in patients with acute coronary syndrome (ACS) post percutaneous coronary intervention (PCI) receiving ticagrelor revealed a differential coronary blood flow velocity response during increasing doses of adenosine compared to placebo or prasugrel treated subjects, respectively. It has also been demonstrated that patients treated with ticagrelor have increased plasma adenosine levels. Therefore, it has been hypothesized that the degree of hyperemia obtained with adenosine infusion may be greater in patients on ticagrelor than that obtained in patients taking clopidogrel or prasugrel. If this proves to be true, it would lead to a lower FFR value with possible important clinical implications in ticagrelor receiving patients in need for FFR measurement. This is a prospective, single center, randomized study of parallel design. Consecutive ticagrelor naive patients who are referred for coronary angiography and have an angiographically moderate to severe de novo stenosis (>50% and <90% diameter by visual assessment) in at least one major epicardial coronary artery amenable to PCI are candidates for this study. Patients after informed consent will be randomized (hour 0) to receive immediately post FFR (with adenosine iintravenous infusion at 140 μg/Kg/min for a 3 minute period) either ticagrelor 180mg loading dose or prasugrel 60mg/clopidogrel 600mg loading dose (as clinically indicated). FFR examination will be repeated 2 hours post loading dose.