Pressure- and 3D-Derived Coronary Flow Reserve with Hydrostatic Pressure Correction: Comparison with Intracoronary Doppler Measurements

Abstract

Purpose: To develop a method of coronary flow reserve (CFR) calculation derived from three-dimensional (3D) coronary angiographic parameters and intracoronary pressure data during fractional flow reserve (FFR) measurement. Methods: Altogether 19 coronary arteries of 16 native and 3 stented vessels were reconstructed in 3D. The measured distal intracoronary pressures were corrected to the hydrostatic pressure based on the height differences between the levels of the vessel orifice and the sensor position. Classical fluid dynamic equations were applied to calculate the flow during the resting state and vasodilatation based on morphological data and intracoronary pressure values. 3D-derived coronary flow reserve (CFRp-3D) was defined as the ratio between the calculated hyperemic and the resting flow and was compared to the CFR values simultaneously measured by the Doppler sensor (CFRDoppler). Results: Haemodynamic calculations using the distal coronary pressures corrected for hydrostatic pressures showed a strong correlation between the individual CFRp-3D values and the CFRDoppler measurements (r = 0.89, p < 0.0001). Hydrostatic pressure correction increased the specificity of the method from 46.1% to 92.3% for predicting an abnormal CFRDoppler < 2. Conclusions: CFRp-3D calculation with hydrostatic pressure correction during FFR measurement facilitates a comprehensive hemodynamic assessment, supporting the complex evaluation of macro-and microvascular coronary artery disease.

Angiography-based Coronary Microvascular Assessment with and without Intracoronary Pressure Measurements ─ a Systematic Review

“…The other two articles utilized a combined approach involving the integration of invasive pressure data with angiographic data acquisition (hereinafter referred to as angiography-and pressure-based methods) and were validated against invasive Doppler-based reference methods 21,22 (Table 3).…”

“…In contrast with IMR, which does not provide information on the vasodilatory capacity of the microcirculation, RRR reliably re ects the ability of the coronary microcirculation to adjust its resistance in response to adenosine and provides prognostic value in both acute myocardial infarction and nonobstructive coronary artery disease [45][46][47] . CFR p−3D was proposed by Tar et al to calculate CFR using invasive intracoronary pressure data and 3D anatomic reconstructions of the target vessel from angiography 22 . Measuring CFR p−3D facilitates the subsequent calculation of the RRR by incorporating distal coronary pressure through the aforementioned formula.…”

“…Tar et al used a similar pressure-based approach to calculate the resistive reserve ratio (RRR p−3D ) by combining classical uid hemodynamic equations with 3D anatomical parameters and invasive intracoronary pressure data from FFR measurements 22 . In their study, distal coronary pressure was corrected for hydrostatic pressure variations that occur due to the level difference between the catheter tip and pressure wire sensor.…”

Pressure Never Lies, but It Should Be Interpreted Thoughtfully: The Role of Hydrostatic Pressure in Coronary Physiology

“…To overcome the problem of uncertain assumption, individual intracoronary pressure can be adopted for calculation following routine invasive FFR measurement. Tar et al developed a method of calculating CFR and the resistive reserve ratio (RRR) using 3D coronary angiographic parameters and intracoronary pressure [ 11 ]. Here, microvascular resistance was calculated using coronary flow from invasive intracoronary pressure gradients measured during routine FFR investigations.…”

“…RRRp-3D demonstrated a good correlation with Doppler-derived RRR, with good limits of agreement with the Doppler-based method. These findings underscore the importance of accounting for hydrostatic pressure to avoid inaccuracies in calculating the driving pressure gradient [ 11 ].…”