In Vivo Validation of Patient‐Specific Pressure Gradient Calculations for Iliac Artery Stenosis Severity Assessment

Abstract

BackgroundCurrently, the decision to treat iliac artery stenoses is mainly based on visual inspection of digital subtraction angiographies. Intra‐arterial pressure measurements can provide clinicians with accurate hemodynamic information. However, pressure measurements are rarely performed because of their invasiveness and the time required. Therefore, the aim of the study was to test the feasibility of a computational model that can predict translesional pressure gradients across iliac artery stenoses on the basis of imaging data only.Methods and ResultsPatients (N=21) with symptomatic peripheral arterial disease and a peak systolic velocity ratio between 2.5 and 5.0 were included in the study. Patients underwent per‐procedural 3‐dimensional rotational angiography and hyperemic intra‐arterial translesional pressure measurements. Vascular anatomical features were reconstructed from the 3‐dimensional rotational angiography data into an axisymmetrical 2‐dimensional computational mesh, and flow was estimated on the basis of the stenosis geometry. Computational fluid dynamics were performed to predict the pressure gradient and were compared with the measured pressure gradients. A good agreement by overlapping error bars of the predicted and measured pressure gradients was found in 21 of 25 lesions. Stratification of the stenosis on the basis of the predicted pressure gradient into hemodynamic not significant (<10 mm Hg) and hemodynamic significant (≥10 mm Hg) resulted in sensitivity, specificity, and overall predictive values of 95%, 60%, and 88%, respectively.ConclusionsThe feasibility of the patient‐specific computational model to predict the hyperemic translesional pressure gradient over iliac artery stenosis was successfully tested. Presented results suggest that, with further optimization and corroboration, the model can become a valuable aid to the diagnosis of equivocal iliac artery stenosis.Clinical Trial Registration URL: http://www.trialregister.nl. Unique identifier: NTR5085.

A comparative study of geometry-based methods and intra-arterial pressure measurements to assess the hemodynamic significance of equivocal iliac artery stenoses

“…The cohort analyzed in this study was a subset of patients from the DETECT-PAD trial (Dutch trial registry: NTR5085). 8 The DETECT-PAD trial included patients of at least 18-years-old with symptomatic PAD due to single or multiple stenoses of the common and/or external iliac artery with a duplex ultrasound (DUS) based peak systolic velocity ratio between 2.5 and 5.5 and/or a visual lumen diameter reduction between 50% and 75% as estimated on Bmode images. Patients with aneurysmatic disease, iliac occlusions or dissections were excluded.…”

“…Rather this was a comparative study, which aims to show how well visual inspection and QVA analysis correlate with the actual intra-arterial pressure gradient in identifying a hemodynamic significant iliac artery stenosis. For a more extensive description of the imaging protocols and pressure measurements, we refer to Huberts et al 9 and Heinen et al, 8 respectively.…”

Novel diagnostic and imaging techniques in endovascular iliac artery procedures

“…Recently, a patient-specific two-dimensional (2D) computational fluid model for equivocal iliac artery stenoses was assessed [7]. This model was based on 3D rotational angiographic image information and validated with intra-arterial pressure measurements under hyperemic conditions (DETECT-PAD trial; http://www.trialregister.nl; identifier: NTR5085, registered on 9 March 2015).…”

“…This model was based on 3D rotational angiographic image information and validated with intra-arterial pressure measurements under hyperemic conditions (DETECT-PAD trial; http://www.trialregister.nl; identifier: NTR5085, registered on 9 March 2015). This model enables a prediction of whether the mean arterial pressure gradient across an equivocal stenosis is hemodynamically significant (≥10 mm Hg) or not significant (<10 mm Hg), with sensitivity of 95%, specificity of 60%, and overall predictive value of 88% [7].…”

“…Overtreatment of hemodynamically nonsignificant stenosis can potentially lead to higher costs and unnecessary complications, whereas treatment of these lesions is unlikely to improve clinical symptoms [6]. In these circumstances, enhancement of standard imaging with functional assessment by calculating the pressure gradient across an equivocal iliac artery stenosis and predictive modeling [7][8][9][10][11] could play a major role in a targeted treatment strategy for the individual patient.…”