Abstract 15117: The Catheter Uncertainty Principle: Does the Presence of a Catheter Alter Hemodynamics?

Abstract

Introduction: Catheters are an essential component of measuring invasive hemodynamic quantities. However, by the very nature of a catheter's presence, it acts to disturb the normal flow field, potentially altering measured pressures and derived quantities, such as FFR. Computational fluid dynamic simulations are performed to explore how vessel lumenal area and catheter size effect pressures. Methods: Patient-specific anatomical reconstructions are coupled with HARVEY, a massively parallel lattice-Boltzmann fluid solver, to calculate 3D blood flow around simulated catheters. We explore the effects of catheter size in vessels ranging from 5 mm in diameter, a right ventricle to pulmonary artery shunt (RVPAS) in a patient with HLHS, and smaller, in coronary arteries. Pressures sampled at the location corresponding to the distal end of the catheter are compared and FFR is calculated for the coronary models. Results: Figure 1A illustrates the calculated pressure waveforms for simulated catheter sizes in a RVPAS. In this case, the catheter does not significantly alter the pressure field unless unrealistically large catheters, such as a 13 Fr, are used. For adult coronary arteries (Figure 1B), reasonable catheter sizes result in appreciable decreases in sampled pressures and, consequently, in calculated FFR (Figure 1C). Conclusion: The presence of a sufficiently large catheter (>50% of the vessel lumenal area) causes a noticeable decrease in the pressures at the tip of the catheter. While unlikely to occur in larger vessels, this can occur during left heart catheterizations of diseased coronary arteries. This causes an artificial decrease in FFR, which can potentially alter clinical decision making. While catheters are the gold standard for pressure measurements, an improved understanding of the inherent sensitivity of their measurements to unobstructed vessel lumenal area is important for interpreting the results of catheter-based diagnostic procedures.