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This old gold tech was the forerunner of FFR  First coronary balloon catheters with side holes  Poor TMPG is poor outcome despite TIMI III epicardial flow  Cineangiography is continued until three cardiac cycles after myocardial  Injection is stopped after opacification of the coronary sinus  Images are obtained with adequate injection allowing reflux of contrast  Best angiographic projection to visualizes subtends myocardium of  Zwolle Myocardial Infarction Study Group in the Netherlands Thought to represent microvascular obstruction or dysfunction  High CTFC despite an open epicardial artery in the setting of AMI is  CTFC of up to 40 is seen in TIMI 3 flow implies vessel is diseased  CTFC is normalized to the TFC to the LAD Standardized distal coronary landmark in the culprit vessel in a single  Number of cine frames required for radiographic contrast to reach a Washout phase) similar to that in an uninvolvedĪrtery. Phase (after 3 cardiac cycles of the washout phaseĪnd noticeably diminishes in intensity during the Mildly/moderately persistent at end of washout Of the washout phase and either does not or onlyĬlears normally and is either gone or only The culprit lesion that is strongly persistent at theĮnd of the washout phase (after 3 cardiac cycles There is myocardial blush in the distribution of Staining present on next injection (~30 seconds). That fails to clear from microvasculature (contrast Myocardial blush in distribution of culprit lesion Myocardium in distribution of culprit artery Minimal or no or opacification (“blush”) of the Stenosis >80% impairs resting blood flow.Epicardial stenosis > 60% (diameter) limits maximal CBF in rest &work.Ratio of maximum hyperaemic flow to resting flow.The myocardial capillary bed after Precapillary arterioles forms anĮxtensive network connecting each myocyte, often referred to as the.Myocardial capillaries and are the primary determinants of coronary Precapillary arterioles connect the epicardial arteries to the.Extravascular mechanical forces acting upon the vasculature Physical characteristics of the blood (viscosity, laminar flowĤ. Organization of the vascular network (series and parallel)ģ. size of individual vessels (length and diameter)Ģ. R3:Intra myocardial capillary resistance is affected by systoleġ. R2:Precapillary arteriole =Auto regulation site=the seat of R1:Epicardial vessel and resistance is zero in health Epicardial vessels are direct conduits and no resistance.Coronary blood flow is inversely related to coronary resistance.ΣEpicardial+precapillary arteriole+ myocardial capillary resistances.Myocardial sleeps in “hibernation” or death(MI).Any compromise in substrate=blood flow switch on alarm of energyĬonservation of energy for the maintenance of cellular function.No oxygen debt as seen in skeletal muscle.ATP is produced and consumed and no storage.Heart assimilates from instantaneous oxidation of FFA, glucose, lactate,.Myocardial blood flow α the balance of myocardial oxygen (MVO2).Maintain myocardial perfusion in systolic BP=60-180 mmHg Some improvement upon the decision of removing stenosis but not The reason : minimal luminal dimensions and area, stenosis length,Įxit and entrance angles, reference vessel diameter, and diffuse Poor correlation of physiologic ischemia Measurements of coronary physiology in the catheterization laboratory provide objective data that complement angiography for clinical decision-making In addition to lesion assessment before and after intervention, emerging applications of coronary physiology include the determination of physiological responses to new pharmacological agents, such as glycoprotein IIb/IIIa blockers, in patients with acute myocardial infarction. The role of microvascular flow impairment can be separately determined with coronary flow velocity reserve measurements. Ambiguity regarding abnormal microcirculation has been reduced or eliminated with measurements of relative coronary flow reserve and fractional flow reserve. Various coronary physiological measurements can be made in the cardiac catheterization laboratory using sensor-tipped guidewires they include the measurement of poststenotic absolute coronary flow reserve, the relative coronary flow reserve, and the pressure-derived fractional flow reserve of the myocardium.