Accuracy of intravascular microcatheter pressure measurements: an experimental study

Intravascular pressure measurements are considered useful for the monitorin g and assessment of endovascular treatment effects,in intracranial vascular malformations. Experimental data on the accuracy of these measurements are limited. A flow phantom with defined intraluminal pressures and pulsatilit y flow waveforms was used in this study. Microcatheters commercially availa ble for neuroendovascular procedures (length 140-155 cm), with different ou ter (0.5-0.83 mm) and inner (0.3-0.53 mm) diameters, were introduced into t he phantom in the direction of flow. Tn a static experiment, pressure value s from 0 to 75 mmHg were applied, and in the dynamic part of the experiment mean pressure values from 25 to 65 mmHg, with a pulsatile amplitude from 7 0 to 170 mmHg were employed. In the static experiment, there was a linear r elationship between the pressure values obtained through the microcatheters and the local transducer of the flow phantom. The pulsatile experiments sh owed increased damping of the pressure waveforms with decreasing inner diam eter of the microcatheters. However, the mean pressure values remained accu rate. This experimental study has shown that mean pressure values can be ac curately measured through microcatheters from 0.3-0.5 mm inner diameter and more than 140 cm in length. In vivo pressure measurements during intervent ional procedures are therefore reproducible and can be used for monitoring of embolization effects in patients.