• distal coronary
  • iFR isolates a specific period in diastole, called the wave-free period, and uses the ratio of distal coronary pressure (Pd) to the pressure observed in the aorta (Pa) over this period. (wikipedia.org)
  • angiographic
  • Baseline characteristics, maximum inflation pressures, types of balloon catheters used, and routinely registered angiographic stenosis properties (severity, length, eccentricity, and calcification) were similar in both groups. (ahajournals.org)
  • Therefore, although the predictive value of these findings is low, detailed evaluation of angiographic morphology of coronary stenoses may improve patient selection and reduce complication rates of PTCA. (ahajournals.org)
  • Results Angiographic % diameter stenosis and reference diameter were 49.6±12.7 and 3.0±0.5 mm, respectively. (ahajournals.org)
  • The best cutoff value of angiographic % diameter stenosis to determine the functional significance was 49.4% in male and 53.0% in female patients. (ahajournals.org)
  • severity
  • Fractional flow reserve, a pressure derived index of stenosis severity, constitutes the best example of the current importance of physiological assessment in clinical practice. (abebooks.com)
  • ischemia
  • We tested the hypothesis that chronic myocardial ischemia (repetitive bouts of coronary stenosis, CS) may induce IPC mediated by different mechanisms. (ahajournals.org)
  • The vast majority of experimental studies in IPC have used a brief episodes of the IPC stimulus on a background of a normal heart with normal coronary arteries, ie, virgin ischemia. (ahajournals.org)
  • To test this hypothesis, we compared the effects of repetitive ischemia, induced by 6 episodes of 90-minute coronary stenosis and 12-hour reperfusion, with a more traditional protocol of IPC, ie, delayed or second-window IPC (SWIPC). (ahajournals.org)
  • The instantaneous wave-free ratio (iFR, sometimes referred to as the instant wave-free ratio or instant flow reserve) is a diagnostic tool used to assess whether a stenosis is causing a limitation of blood flow in coronary arteries with subsequent ischemia. (wikipedia.org)
  • The CLARIFY study was a physiological study in which iFR and FFR were compared to an independent third measure, hyperaemic stenosis resistance (HSR) which uses a combination of pressure and flow assessment to detect ischemia. (wikipedia.org)
  • Ischemic
  • Ischemic episodes occur when pressure distal to the stenosis falls below that needed to perfuse the subendocardium. (ahajournals.org)
  • Methods and Results- To test this, chronically instrumented conscious pigs were subjected to either repetitive coronary stenosis (RCS) or a traditional protocol of second-window ischemic preconditioning (SWIPC). (ahajournals.org)
  • Reflex constriction of significant coronary stenosis as a mechanism contributing to ischemic left ventricular dysfunction during isometric exercise. (ahajournals.org)
  • In stenoses classified as ischemic, the wave-free period provided a similar reduction in microvascular resistance as adenosine-mediated hyperaemia over the whole cardiac cycle. (wikipedia.org)
  • functionally
  • Measurement of coronary flow reserve can be used to identify functionally important luminal narrowing of the LAD artery. (ahajournals.org)
  • 13 We hypothesized that PC-MRI flow reserve measurements could be used to identify functionally important stenoses in the anterior epicardial arterial circulation. (ahajournals.org)
  • CTA offers a valuable alternative for the diagnosis of CAD but its value in the detection of functionally relevant coronary stenoses remains uncertain. (ahajournals.org)
  • luminal
  • During handgrip with intracoronary nitroglycerin, the pressure-rate product again increased 33%, but relative to resting control, capillary wedge pressure fell 4 mm Hg in association with a 32% increase in luminal area of the stenosis and a 28% reduction in flow resistance (all significantly different from the response to handgrip alone: p less than .001, .01, and .005, respectively). (ahajournals.org)
  • proximal
  • The redistribution of thallium-201 (201Tl) after coronary vasodilation was studied in 14 dogs with a proximal stenosis of the left circumflex coronary artery that did not reduce basal flow but attenuated reactive hypermia. (ahajournals.org)
  • Methods and Results -Thirty subjects (23 men, 7 women, age 36 to 77 years) underwent MRI visualization of the left main and LAD coronary arteries as well as measurement of flow in the proximal, middle, or distal LAD both at rest and after intravenous adenosine (140 μg/kg per minute). (ahajournals.org)
  • Since patients with significant narrowing of the left main or proximal left anterior descending (LAD) coronary arteries have improved survival with coronary artery bypass grafting, 1 2 3 the reliable identification of these individuals is important. (ahajournals.org)
  • Wellens' syndrome is an electrocardiographic manifestation of critical proximal left anterior descending (LAD) coronary artery stenosis in patients with unstable angina. (wikipedia.org)
  • invasive
  • 4 5 6 Because invasive techniques are associated with some morbidity and mortality and are relatively expensive, 7 a noninvasive method of identifying and determining the functional importance of a stenosis in the left anterior epicardial arteries of humans would have substantial clinical utility. (ahajournals.org)
  • It is a non-invasive test, is generally regarded as a safe (see below) procedure and is well tolerated by patients (apart from people who suffer from claustrophobia) The majority of scans are performed using a stress/rest protocol using adenosine as the stressor which acts to induce ischaemia in the myocardium by the coronary 'steal' phenomenon. (wikipedia.org)
  • Circulation
  • However, the acceptance of FFR by cardiologists contrasts with important voids in knowledge on the basic principles of coronary physiology and of other available techniques that, as an alternative to FFR, allow a more comprehensive assessment of coronary circulation. (abebooks.com)
  • Cardiac stress tests compare the coronary circulation while the patient is at rest with the same patient's circulation during maximum physical exertion, showing any abnormal blood flow to the myocardium (heart muscle tissue). (wikipedia.org)
  • significance
  • However, little is known about the gender influence on the functional significance of coronary artery stenosis. (ahajournals.org)
  • Conclusion Compared to male patients, female patients may have higher anatomical threshold for the functional significance of coronary artery stenosis. (ahajournals.org)
  • The functional significance of the coronary collateral vessels is a matter of continuing experimental investigation although their existence has been known for over three centuries and been documented repeatedly in man and beast over the past seven decades. (wikipedia.org)
  • complications
  • How to manage complications in the treatment of a resistant coronary stenosis? (pcronline.com)
  • However, if stenoses are not flow limiting, then they can be safely left alone without stenting or surgery and this help reduce patient's exposure to unnecessary procedures and potential complications. (wikipedia.org)
  • aortic
  • In three of the four patients with stenosis of both the supravalvular aortic ring and the sinus of Valsalva, a pressure gradient was demonstrated. (ahajournals.org)
  • The degree of supravalvular aortic stenosis correlated with the serum cholesterol level but not with patient age. (ahajournals.org)
  • Fractional
  • Fractional flow reserve (FFR), coronary flow reserve (CFVR), and velocity-based indices of stenosis resistance (h-SRv) and microvascular resistance (h-MRv) at maximal hyperemia were compared. (ahajournals.org)
  • More commonly coronary pressure measurements are used as a surrogate for flow measurement and techniques include iFR and fractional flow reserve (FFR). (wikipedia.org)
  • Fractional flow reserve is defined as the pressure after (distal to) a stenosis relative to the pressure before the stenosis. (wikipedia.org)
  • lumen
  • This extremely important morphologic feature of stenoses permits transient variation in stenosis lumen diameter in response to drugs or to variation in endogenous vasomotor activity or intraluminal pressure. (ahajournals.org)
  • IVUS is of use to determine both plaque volume within the wall of the artery and/or the degree of stenosis of the artery lumen. (wikipedia.org)
  • IVUS enables accurately visualizing not only the lumen of the coronary arteries but also the atheroma (membrane/cholesterol loaded white blood cells) "hidden" within the wall. (wikipedia.org)
  • citation needed] The range of lumen stenosis locations at which myocardial infarctions occurred ranged from areas of mild dilation all the way to areas of greater than 95% stenosis. (wikipedia.org)
  • resistance
  • As a result, seemingly small changes in diameter are amplified to large changes in stenosis resistance. (ahajournals.org)
  • This was shown across a variety of stenosis severities and demonstrated that over that specific period in diastole, microcirculatory resistance was the lowest and most stable compared to the rest of the cardiac cycle. (wikipedia.org)