MD Conference Express TCT 2011 - (Page 8)
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vasodilatation. The investigators found that resistance that was measured at rest during the wave-free period was similar in both stability (p=0.96) and magnitude (p=0.70) to values that were achieved under adenosine hyperemia. The second part of the study evaluated whether the assessment of the significance of a coronary stenosis was numerically similar using iFR and FFR in 157 patients. iFR is defined as an instantaneous pressure ratio across a stenosis during the wave-free period, when resistance is constant and minimized in the cardiac cycle. The FFR was measured following administration of intravenous adenosine to achieve maximal hyperemia. Measurement of iFR during the wave-free period provided a measure of stenosis severity that was similar to the FFR measurement (r=0.90, regression coefficient y=1.022x + 0.03; Figure 1). The small difference between iFR and FFR was not explained by the magnitude of hyperemia (Figure 2). Figure 1. Close relationship between iFR and FFR.
Left Coronary Artery 1.0 r=0.90 Regression coefficiet y=1.022x + 0.03 Right Coronary Artery
sensitivity of 85%, and specificity of 91%. After adjustment for the inherent variability in FFR, diagnostic accuracy was 95%, positive predictive value was 97%, negative predictive value was 93%, sensitivity was 93%, and specificity was 97% (Figure 3). Figure 3. Assessment of Diagnostic Efficiency of iFR After Adjustment for Inherent Variability in FFR.
Left Coronary Artery 1.0 False (+) Right Coronary Artery
0.8
FFF
0.6 False (-) 0.4
0.2 iFR positive 0 iFR negative
Diagnostic accuracy (+) predictive value (-) predictive value Sensitivity Specificity 88% 91% 85% 85% 91%
Adjusting for Variability in FFR 95% 97% 93% 93% 97%
Reproduced with permission from J. Davies, MD, PhD.
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0.6
0.4
0.2
0
The ADVISE study identified a wave-free period in the cardiac cycle when resistance is naturally stabilized and minimal, obviating the need for administration of adenosine. iFR that is measured during this wave-free period gives a measure of stenosis severity that is similar to that provided by FFR. The clinical implications of these results include removal of barriers to adoption of physiological assessment, increased applicability, improved work flow in the catheter laboratory, and improved patient experience.
0.4 FFR 0.6 0.8 1.0
iFR
0
0.2
Reproduced with permission from J. Davies, MD, PhD.
Figure 2. Magnitude of Hyperemia.
1.0 0.8 0.6 0.4 r2=0.000
Point-of-Care Genetic Testing Facilitates Rapid Personalization of Antiplatelet Therapy
Previous studies suggest that CYP2C19 loss-of-function alleles affect clopidogrel metabolism and are associated with major adverse cardiac events (MACE) and stent thrombosis. CYP2C19*2 accounts for 95% of CYP2C19 loss-of-function alleles and occurs in up to 25% of Caucasian populations and 40% of Asian populations.
∆ FFR-iFR
0.2 0 -0.2 -0.4 -0.6 -0.8 -1.0 0 2.5 ∆ Abs Hyperaemic - wave-free resistance (mm Hg s/m) 5
Reproduced with permission from J. Davies, MD, PhD.
Assessment of the diagnostic efficiency of iFR demonstrated a diagnostic accuracy of 88%, positive predictive value of 91%, negative predictive value of 85%,
Currently, most genetic testing is done in central laboratories, with a turnaround time of 2 to 7 days. This delay has prevented the prospective evaluation of genetic testing in percutaneous coronary intervention (PCI) studies. The University of Ottawa Heart Institute, in collaboration with Spartan Biosciences, created the first
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December 2011
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Table of Contents for the Digital Edition of MD Conference Express TCT 2011
MD Conference Express TCT 2011
Contents
TAVI Improves QoL in Patients Suitable for Transfemoral TAVI: PARTNER Cohort A
Results from the PARTNER Trial (Cohort A): Transfemoral TAVI Economically Attractive but Transapical TAVI More Costly
PARTNER Cohort B: TAVI Superior to Standard Therapy at Two Years
Transapical TAVI Inferior to SAVR in Operable Elderly Patients
Primary Results from ADVISE: Validation of a Vasodilator Independent Measure of Coronary FFR
Point-of-Care Genetic Testing Facilitates Rapid Personalization of Antiplatelet Therapy
Bioabsorbable Polymer Stent Noninferior to Permanent Polymer Stent
BRIDGE Study Demonstrates Feasibility and Safety of Cangrelor
MD Conference Express TCT 2011
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