Coronary Physiology in the Cardiac Catheterization Laboratory

Figures

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  Figure 1. Effect of coronary stenosis on coronary flow reserve. Reprinted with permission from Gould 2009, adapted from Gould et al. 1974 [9]. Experimental model of coronary blood flow at rest and the maximal achievable flow. In the presence of a stenosis resting flow is not limited until a coronary stenosis reaches 85% luminal obstruction. However, maximal achievable flow is limited at stenoses as low as 30–40%. The ratio of the maximal achievable coronary blood flow to the resting blood flow is the coronary flow reserve (CFR).

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  Figure 2. Coronary Artery Translesional Pressure Measurement in the First Angioplasty (1978). Reprinted and adapted from EuroIntervention Vol 13/number 1, Meier, B, “His master’s art, Andreas Grüntzig’s approach to performing and teaching coronary angioplasty”, Pages 15–27, Copyright (2017), with permission from Europa Digital & Publishing [20]. Hemodynamic assessment of coronary stenosis during the first coronary angioplasty by Dr. Andreas Gruentzig in 1978. The pressure tracing on top labeled AoP is the aortic pressure. The bottom tracing CoP is the coronary pressure at the distal tip of the pressure-monitoring lumen of the balloon dilatation catheter. Distal to the stenosis there is a significant drop in the coronary pressure that is improved after balloon inflation and dilatation of the stenosis. This was the initial report of the “translesional pressure gradient” in a human coronary artery.

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  Figure 3. Non-invasive assessment of ischemia compared with FFR. Reprinted with permission from Pijls et al. [22]. In 45 patients with chest pain and moderate (~50%) coronary artery stenosis, exercise stress testing, thallium scintigraphy, and stress echocardiography with dobutamine were performed. These results were compared with FFR measurements. The dashed line indicates the pre-specified FFR threshold for ischemia of 0.75 and each circle represents patients who were found to have ischemia or no ischemia by stress testing. Nearly every patient with ischemia by stress testing was found to have a coronary stenosis with an ischemic FFR value. After revascularization non-invasive tests were repeated and there was no longer evidence of ischemia.

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  Figure 4. Fractional flow reserve (FFR) values and angiographic severity of lesions in the FAME trial. Reprinted with permission from Jeremias et al., 2017 [14] (which was adapted from Tonino et al 2010) [26]. Angiographic findings of the FFR-guided revascularization arm in the FAME trial [25]. Scatterplot of FFR values shows significant heterogeneity in the physiological significance of angiographic stenoses. Stenoses of 50–70% angiographic severity were found to have an ischemic FFR (0.8, red bar) in 35% of cases. In angiographic stenoses of 71–90%, FFR was in the ischemic zone in 80% of cases. In 91–99% angiographic stenoses FFR was ischemic in 96% of cases.