It is also correlated with volumetric flow and resting distal average peak velocity. The CTFC technique is a simple and inexpensive technique for calculation of coronary flow reserve, and is highly correlated ( r =0.88, P =0.0001) with coronary flow reserve measurements obtained using the Doppler guidewire. Pacing at a faster heart rate (20 beats/min) reduced the CTFC by 5 frames. Injections during diastole reduce the CTFC by 6 frames. It is therefore important to standardize use of nitrates in studies that involve CTFC measurement, or to at least confirm that nitrate use is well balanced across arms of the trial. Administration of nitrates, which cause enlargement of the artery and the volume to be filled with dye significantly, increases the CTFC by approximately 6 frames. Alterations in catheter size do not affect CTFC measurements.
#Timi iii flow trial#
Varying the force of dye injection may change the frame count by up to 2 frames, which is a relatively small and insignificant difference from a clinical trial perspective. Differences between observers are less than 0.75 frames and the correlation between observers is 0.97-0.99. Highly reproducible results are obtained with very low interobserver and intraobserver variability. For example, in the use of images acquired at 15 frames/s, frame counts are multiplied by a factor of 2 to derive the CTFC.
Centers that use image acquisition at speeds other than the most widely used frame rate in the US of 30 frames/s need to adjust CTFC assessments accordingly. The number of frames from the first frame to the last frame when dye enters the standardized distal landmark is counted. The standardized distal landmarks are taken as the first branch of the posterolateral artery for the right coronary artery, most distal branch of the obtuse marginal branch for the circumflex, and the distal bifurcation for the LAD (also known as the 'whale's tail' branch of the LAD). The first frame taken for measurements is the frame in which dye touches both borders of the coronary artery and moves forward with at least 70% opacification of the vessel lumen. The frame count number after adjustment for vessel length is given the term 'corrected TIMI frame count'. A correction factor is required to compensate for the longer length of the left anterior descending artery (LAD) compared with the circumflex and right coronary arteries (the number of frames required for dye to traverse the LAD is divided by 1.7). TIMI 2 flow (partial reperfusion) is delayed or sluggish antegrade flow with complete filling of the distal territory.In the CTFC method, the number of frames required for dye to reach a standardized distal landmark is counted.TIMI 1 flow (penetration without perfusion) is faint antegrade coronary flow beyond the occlusion, with incomplete filling of the distal coronary bed.TIMI 0 flow (no perfusion) refers to the absence of any antegrade flow beyond a coronary occlusion.'TIMI Grade Flow' is a scoring system from 0-3 referring to levels of coronary blood flow assessed during percutaneous coronary angioplasty: TIMI risk can be calculated on the TIMI website under "Clinical Calculators." 'TIMI risk' estimates mortality following acute coronary syndromes. % risk at 14 days of: all-cause mortality, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization. ST changes of at least 0.5mm on admission EKG At least 2 angina episodes within the last 24hrs Or female first-degree relative or mother less than 65). (CAD in male first-degree relative, or father less than 55, Such as: Hypertension -> 140/90 or on antihypertensives, Known Coronary Artery Disease (CAD) (coronary stenosis >= 50%) Aspirin use in the last 7 days (patient experiences chest pain despite ASA use in past 7days) TIMI Score Calculation (1 point for each): It is used to categorize a patient's risk of death and ischemic events and provides a basis for therapeutic decision making. The TIMI Risk Score is used in patients with U nstable Angina / Non-ST Elevation Myocardial Infarction. It has conducted numerous practice-changing clinical trials in patients with cardiovascular disease or risk factors for cardiovascular disease TIMI stands for ' Thrombolysis In Myocardial Infarction' and is the name of an Academic Research Organization (ARO) which was founded by Dr.
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