Objective
Angiography remains a critical component for diagnostic imaging and therapeutic intervention in peripheral arterial disease (PAD). The goal of this study was to compare angiography to corresponding intravascular ultrasound (IVUS) imaging of the same vessels in patients with PAD.
Methods
From 2004–2008, patients undergoing angiography for PAD (n=93) were recruited in a prospective observational analysis. At the time of angiography, diseased lower extremities were interrogated via a 10-cm IVUS pullback with registration points. IVUS data were analyzed with radiofrequency techniques for vessel and lumen diameter, plaque volume, plaque composition, and cross-sectional area (VH™, Volcano Corp). Similarly, vascular surgeons (n=3) blinded to the IVUS data graded corresponding angiographic images according to vessel diameter, degree of stenosis, degree of calcification, and extent of eccentricity. Statistical analyses of matched IVUS/angiograms were performed utilizing SPSS 16.0 (Chicago, IL).
Results
The distribution of demographic and risk variables were typical for PAD: 54% male, 96% hypertension, 78% hyperlipidemia, 44% diabetic, 87% tobacco history, 65% coronary artery disease, and 10% end-stage renal disease. Symptoms precipitating the angiographic evaluation included claudication (53%), rest pain (18%), and tissue loss (29%). Angiographic and IVUS interpretation were similar for luminal diameters, but external vessel diameter was greater via IVUS (7.0 ± 0.7 vs. 5.2 ± 0.8 mm, P < 0.05). There was a significant correlation for stenosis determination (r=0.84) utilizing the two-dimensional diameter method; however, IVUS determination of vessel area stenosis was greater by 10% (95% confidence interval = 0.3–21%, P<0.05). IVUS indicated that a higher proportion of plaques were concentric. Grading of calcification was moderate/severe in 40% by angiography, but only 7% by IVUS (P < 0.05).
Conclusions
In the evaluation of peripheral arterial disease, angiography and IVUS provide similar luminal diameters and diameter-reducing stenosis measurements. Determination of overall vessel diameter, and interpretation of plaque morphology by angiography are discordant from IVUS derived data.